WO2018230210A1

WO2018230210A1 - Hot melt adhesive

Info

Publication number: WO2018230210A1
Application number: PCT/JP2018/018194
Authority: WO
Inventors: 麻希佐見津; 周平有田
Original assignee: 株式会社Moresco
Priority date: 2017-06-12
Filing date: 2018-05-10
Publication date: 2018-12-20
Also published as: CN110741058A; JP6854889B2; JPWO2018230210A1

Abstract

One aspect of the present invention is a hot melt adhesive containing a thermoplastic polymer, a tackifier, and a softening agent, wherein: the thermoplastic polymer contains a copolymer comprising a first block which comprises a conjugated diene-based compound and a second block which comprises a vinyl aromatic hydrocarbon and/or a hydrogenated product of the copolymer; the copolymer is such that the content of the second block is less than 30 mass% and the content of a diblock structure of the first block and the second block is 10 mass% or more; the content of the copolymer and the hydrogenated product thereof is 55 mass% or more relative to the overall quantity of the thermoplastic polymer; and the content of the softening agent is 15-30 parts by mass relative to 100 parts by mass of the hot melt adhesive.

Description

Hot melt adhesive

The present invention relates to a hot melt adhesive.

A hot melt adhesive is applied to an adherend that is an object to be bonded in a melted state by heating, and the adherends are held in contact with each other via the melted hot melt adhesive. Thus, the adherends are bonded to each other. Such hot melt adhesives include, for example, packaging fields such as cardboard and small boxes, sanitary material fields such as paper diapers and sanitary products, bookbinding fields, plywood fields, woodworking fields, automobile fields, home appliance fields, and housing fields, etc. It is used in various fields.

Also, as described above, the hot melt adhesive is used in a melted state by heating, so that no solvent is required. For this reason, the hot melt adhesive is preferably used in the sanitary material field, for example, as an adhesive having high safety to the human body. Specifically, hot-melt adhesives are widely used for fixing and assembling components of disposable sanitary materials such as disposable diapers and sanitary products.

When using a hot melt adhesive in such a sanitary material field, there are many opportunities to come into contact with moisture such as body fluids because of its use. It is known that some hot melt adhesives have poor adhesive properties when contacted with moisture, that is, poorly wet adhesive properties. In such a hot melt adhesive, in a field where there are many opportunities for contact with moisture, adhesion between the constituent materials is not maintained when the product is used, and the product itself may collapse. Specifically, hydrophilic sanitary materials, such as a paper diaper, use hydrophilic porous substrates, such as a ground pulp used as an absorber of a tissue and a paper diaper. When such a hydrophilic porous substrate is fixed with a hot melt adhesive, when the hydrophilic porous substrate is wet with a body fluid such as urine and becomes wet, the adhesive strength by the hot melt adhesive is increased. There is a risk of significant reduction. Thus, when the adhesive strength decreases, the hydrophilic porous base material used as the absorbent becomes insufficiently fixed, and the absorbent body is displaced from the original position with the movement of the legs and hips. There arises a problem that it cannot be properly absorbed. For these reasons, hot melt adhesives are required to maintain adhesiveness in a wet state so that excellent adhesive strength can be maintained even for a hydrophilic porous substrate in a wet state. Yes.

Examples of the adhesive intended to improve the adhesiveness in such a wet state include the adhesives described in Patent Documents 1 to 4.

Patent Document 1 discloses a group consisting of a styrene-isoprene-styrene block copolymer, a styrene-butadiene-styrene block copolymer, and a styrene-butadiene / butylene-styrene having a styrene component content of 15 to 35% by mass. 100 parts by weight of a thermoplastic block copolymer containing at least one selected from the group consisting of 0.05 to 10 parts by weight of a liquid rubber having a carboxyl group and / or a carboxylic acid anhydride group in the molecule, and a tackifier A hot melt adhesive composition containing is described. According to Patent Document 1, it is disclosed that it is possible to express excellent adhesive strength to a wet hydrophilic porous substrate even at a relatively low temperature, and that it is excellent in thermal stability. .

In Patent Document 2, a hot block containing a thermoplastic block copolymer, which is a copolymer of a vinyl aromatic hydrocarbon and a conjugated diene compound, and a wax modified with a carboxylic acid and / or a carboxylic anhydride. A melt adhesive is described. According to Patent Document 2, it is disclosed that wet adhesion is improved, and more preferably, at least one selected from low-temperature adhesion, viscosity, adhesion, odor, and economy is improved.

Patent Document 3 discloses a hot for disposable products containing a propylene homopolymer having a melting point of 100 ° C. or less obtained by polymerizing propylene using a metallocene catalyst, and a wax modified with carboxylic acid and / or carboxylic anhydride. A melt adhesive is described. According to Patent Document 3, it is disclosed that it is suitable for high-speed coating and is excellent in adhesiveness in a wet state and low-temperature coating.

Patent Document 4 discloses a block copolymer of a vinyl aromatic hydrocarbon and a conjugated diene compound and a thermoplastic block copolymer containing at least one of hydrogenated products thereof, and unsaturated carboxylic acids or anhydrides thereof. A hot melt adhesive containing an acid-modified petroleum resin that has been acid-modified by a product is described. According to Patent Document 4, it is disclosed that wet adhesion is improved with respect to the constituent members without causing deterioration of thermal stability or generation of odor.

As described above, the hot melt adhesive is required to improve the adhesiveness in a wet state. In order to improve the adhesiveness in the wet state, even when a certain time or more has elapsed with the hot melt adhesive in a wet state being loaded, the occurrence of deformation of the hot melt adhesive may be suppressed. Desired. That is, it is also required to suppress the occurrence of the creep phenomenon in a wet state. The adhesiveness in the wet state can also be improved by suppressing the occurrence of the creep phenomenon in the wet state. For this reason, the hot melt adhesive is required to sufficiently suppress the occurrence of a creep phenomenon in a wet state and to have excellent adhesiveness in a wet state.

JP2015-28118A JP 2007-169531 A JP 2013-64054 A Japanese Patent Laying-Open No. 2015-91917

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a hot melt adhesive that can sufficiently suppress the occurrence of a creep phenomenon in a wet state and is excellent in adhesiveness in a wet state. .

One aspect of the present invention is a hot melt adhesive containing a thermoplastic polymer, a tackifier, and a softening agent, wherein the thermoplastic polymer includes a first block composed of a conjugated diene compound and a vinyl aromatic. A copolymer comprising a second block comprising a hydrocarbon, and at least one of a hydride of the copolymer, wherein the copolymer has a content of the second block of less than 30% by mass, A copolymer in which the content of the diblock body of the first block and the second block is 10% by mass or more, wherein the content of the copolymer and the hydride of the copolymer is the thermoplasticity. A hot melt adhesive characterized in that it is 55% by mass or more based on the total amount of the polymer, and the content of the softener is 15 to 30 parts by mass with respect to 100 parts by mass of the hot melt adhesive. Ah .

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description.

In the bonding method using a hot melt adhesive, first, a hot melt adhesive melted by heating is applied to an adherend using a coating machine or the like. By holding the other adherend in contact with the applied hot melt adhesive, the adherends can be adhered to each other.

In the field of sanitary materials such as disposable diapers, it is required to improve the texture. For this reason, it has been studied to increase the flexibility of paper diapers and the like and improve the texture by making the constituent materials thin. However, as the constituent material becomes thinner, its heat resistance tends to decrease. When a hot-melt adhesive melted by heating is applied to a constituent material having low heat resistance, the constituent material may be damaged, for example, melted or deformed. And the damage by the heat | fever of this constituent material had the tendency for it to generate | occur | produce easily when the temperature of the hot-melt-adhesive to apply | coat is high, or when the quantity of the hot-melt-adhesive to apply | coat is large. Therefore, in order to be able to use such a low heat-resistant constituent material, in the sanitary material field, low temperature application and small amount application of a hot melt adhesive is required. In addition, due to the improved performance of the coating equipment and the like, it has become possible to realize low temperature application and small amount application of a hot melt adhesive.

For these reasons, there is a demand for hot melt adhesives that can be suitably bonded even when applied at low temperatures and in small amounts. That is, even if the amount of hot melt adhesive applied is reduced by reducing the nozzle diameter of the coating machine, etc. and the temperature at which the hot melt adhesive is melted is lowered, There is a need for hot melt adhesives that can ensure good adhesion. Patent Documents 1 to 4 disclose that the adhesiveness in a wet state can be improved as described above. From this, it is conceivable to use the adhesives described in Patent Documents 1 to 4.

However, according to the study by the present inventors, when the adhesives described in Patent Documents 1 to 4 are used as hot melt adhesives, even if the adhesiveness in a wet state can be improved, In the case of application in a small amount, the adhesiveness in the wet state may not be sufficiently improved. Specifically, when the adhesives described in Patent Documents 1 to 4 are adhered by low temperature application and small amount application, when a sanitary material such as a paper diaper is used for a long time, the hydrophilic porous substrate is fixed. The hot melt adhesive that has been stored becomes wet. When a certain time or more has elapsed with a load applied to the hot melt adhesive in such a wet state, the hot melt adhesive is deformed. That is, the creep phenomenon may occur in a wet state. In such a case, the hydrophilic porous substrate fixed with the hot melt adhesive moves from the original position.

Therefore, the hot melt adhesive is required to improve the adhesiveness in the wet state, and in order to realize this, it is required to sufficiently suppress the occurrence of the creep phenomenon in the wet state.

As a result of various studies, the inventor of the present invention can sufficiently suppress the occurrence of a creep phenomenon in a wet state and provide a hot melt adhesive excellent in adhesiveness in a wet state. I found it to be achieved.

The present inventor, when using hot melt adhesive in low temperature application and small amount application, even if it can improve the adhesion in the wet state, the reason why the creep phenomenon in the wet state cannot be sufficiently suppressed I guessed as follows.

First, when a hot melt adhesive is used for low temperature application and small amount application, the amount of heat of the hot melt adhesive at the time of coating decreases, and the hot melt adhesive is less likely to soak into the hydrophilic porous substrate that is the adherend. It is considered to be. Thereby, even if the adherends are bonded to each other with the hot melt adhesive, it is considered that the adherend and the hot melt adhesive are in contact only in the vicinity of the surface of the adherend. For this reason, it is considered that the hot melt adhesive is likely to be deformed when a certain time or more elapses in a wet state with a load applied to the hot melt adhesive. That is, it is considered that an interfacial fracture that peels off at the interface between the hot melt adhesive and the adherend tends to occur due to the creep phenomenon.

Therefore, the present inventor has paid attention to increasing the affinity of the hot melt adhesive with the hydrophilic porous substrate so that the hot melt adhesive can easily penetrate into the hydrophilic porous substrate. It was investigated. As a result, the following hot melt adhesives have been conceived.

Hereinafter, embodiments according to the present invention will be described, but the present invention is not limited thereto.

The hot melt adhesive according to an embodiment of the present invention includes a thermoplastic polymer, a tackifier, and a softener. The thermoplastic polymer includes at least one of a copolymer composed of a first block composed of a conjugated diene compound and a second block composed of a vinyl aromatic hydrocarbon, and a hydride of the copolymer. Further, in this copolymer, the content of the second block is less than 30% by mass, and the content of the diblock body of the first block and the second block is 10% by mass or more. It is a polymer. Furthermore, content of the said copolymer and the hydride of the said copolymer is 55 mass% or more with respect to the said thermoplastic polymer whole quantity. In addition, the content of the softening agent is 15 to 30 parts by mass with respect to 100 parts by mass of the hot melt adhesive.

This hot melt adhesive contains, as the thermoplastic polymer, at least one of the copolymer and a hydride of the copolymer in a total of 55% by mass or more, and further, a softener is added to the hot melt adhesive. By including 15 to 30 parts by mass with respect to 100 parts by mass of the agent, the occurrence of creep phenomenon in a wet state can be suppressed.

This is thought to be due to the following.

First, the second block is a block composed of vinyl aromatic hydrocarbons, so-called hard segments, forms aggregates with other hard segments, and in the copolymer, the bonding points between the molecular chains are determined. It is thought to form. Since the copolymer has a relatively small content of such second blocks, it is considered that the number of bonding points between molecular chains is relatively small. The first block is a block made of a conjugated diene compound and is called a so-called soft segment. By having such a first block, the hot melt adhesive containing the copolymer is considered to be a highly flexible adhesive. Further, the copolymer includes a diblock body of the first block and the second block. And this diblock body will have the 2nd block which can become a junction of molecular chains in one edge part, and does not work as a crosslinking agent. The copolymer contains a certain amount or more of a diblock body that does not act as such a crosslinking agent. Thus, by adjusting the content of each of the second block and the diblock body in the copolymer, the hot melt adhesive containing the copolymer is a hydrophilic porous material that is an adherend. It is considered that it easily penetrates into the inside of the base material. The hydride of the copolymer is considered to work in the same manner as the copolymer. Since such a copolymer and its hydride are contained in a certain amount or more, the hot melt adhesive is considered to be flexible and easily penetrate into the adherend. Further, since a predetermined amount of the softening agent is contained, it is considered that the hot melt adhesive can be suitably applied even in a small amount. Therefore, the hot melt adhesive can be suitably applied to a hydrophilic porous substrate as an adherend, easily penetrates into the inside, and has flexibility, so that the occurrence of a creep phenomenon in a wet state is preferable. It can be suppressed.

First, as described above, the thermoplastic polymer used in the present embodiment includes either one of the copolymer and a hydride of the copolymer, and the total of them includes the total amount of the thermoplastic polymer. If it is 55 mass% or more, it will not specifically limit. Moreover, the content rate of the said hydride of the said copolymer and the said copolymer is 55 mass% or more with respect to the said thermoplastic polymer whole quantity, and it is preferable that it is 75 mass% or more. Further, the thermoplastic polymer may consist of only the copolymer and a hydride of the copolymer, that is, the content of the copolymer and the hydride of the copolymer is 100% by mass. It may be. When the amount of the copolymer is too small, there is a tendency that the effects of including the copolymer, such as easy penetration into the hydrophilic porous substrate that is the adherend, cannot be exhibited sufficiently.

Further, the copolymer is a copolymer composed of a first block made of a conjugated diene compound and a second block made of a vinyl aromatic hydrocarbon.

The first block is a block made of a conjugated diene compound, that is, a block derived from a conjugated diene compound. Specific examples of the first block include a polymer obtained by polymerizing a conjugated diene compound (a polymer of a conjugated diene compound). The conjugated diene compound is not particularly limited as long as it is a diolefin compound having at least a pair of conjugated double bonds. Specific examples of the conjugated diene compound include butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3. -Hexadiene and the like. Of these, butadiene and isoprene are preferred as the conjugated diene compound. Moreover, as said conjugated diene type compound, the said exemplary compound may be used independently, and may be used in combination of 2 or more type.

The second block is a block made of vinyl aromatic hydrocarbon, that is, a block derived from vinyl aromatic hydrocarbon. Specific examples of the second block include a polymer obtained by polymerizing vinyl aromatic hydrocarbon (polymer of the vinyl aromatic hydrocarbon). The vinyl aromatic hydrocarbon is not particularly limited as long as it is an aromatic hydrocarbon having a vinyl group. Specific examples of the vinyl aromatic hydrocarbon include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, and vinyl. Anthracene etc. are mentioned. Of these, styrene is preferred as the vinyl aromatic hydrocarbon. Moreover, as said vinyl-type aromatic hydrocarbon, the compound of the said illustration may be used independently, and may be used in combination of 2 or more type.

In the copolymer, the content of the second block is less than 30% by mass with respect to the copolymer, preferably 5 to 25% by mass, and preferably 15 to 25% by mass. Is more preferable. When the content of the second block is a relatively small content within the above range, a highly flexible adhesive can be obtained while suitably functioning as a bonding point between molecular chains.

The diblock body content of the first block and the second block is 10% by mass or more, preferably 30 to 90% by mass, and preferably 50 to 80% by mass with respect to the copolymer. % Is more preferable. Further, the copolymer may consist of only the diblock body, that is, the content of the diblock body of the first block and the second block is 100 with respect to the copolymer. It may be mass%. When there are too few said diblock bodies, a triblock body etc. will increase and there exists a tendency for the softness | flexibility of the adhesive agent obtained to fall. When the content of the diblock body is within the above range, a highly flexible adhesive can be obtained while suitably functioning as a bonding point between molecular chains.

Specific examples of the copolymer and the hydride of the copolymer include, for example, a styrene-butadiene block copolymer, a styrene-isoprene block copolymer, a hydrogenated styrene-butadiene block copolymer, and a hydrogenated styrene. -Isoprene block copolymers and the like. These copolymers may contain a triblock body as long as the content of the diblock body is within the above range. Examples of the triblock body include a styrene-butadiene-styrene block copolymer (SBS) in the case of a styrene-butadiene block copolymer. In the case of a styrene-isoprene block copolymer, for example, styrene-isoprene-styrene block copolymer (SIS) and the like can be mentioned. In the case of a hydrogenated styrene-butadiene block copolymer, for example, styrene-ethylene-butylene-styrene block copolymer (SEBS) and the like can be mentioned. Further, in the case of a hydrogenated styrene-isoprene block copolymer, for example, styrene-ethylene-propylene-styrene block copolymer (SEPS) and the like can be mentioned.

Further, the thermoplastic polymer only needs to contain 55% by mass or more of the copolymer and a hydride of the copolymer, and a thermoplastic polymer other than the copolymer and the hydride of the copolymer (others). A thermoplastic polymer). The other thermoplastic polymer is not particularly limited as long as it is a thermoplastic polymer used as a component constituting a hot melt adhesive. Moreover, as this thermoplastic polymer, the thermoplastic polymer etc. which are used as a base polymer which is a main component of a hot-melt-adhesive are mentioned. Specific examples of the thermoplastic polymer include elastomeric, olefinic, ethylene vinyl acetate copolymer (EVA) based, polyester based, polyamide based, and polyacrylic thermoplastic polymers. Among these, in the present embodiment, the elastomer-based thermoplastic polymer and the olefin-based thermoplastic polymer are preferable, and the elastomer-based thermoplastic polymer is more preferable.

The elastomer-based thermoplastic polymer includes the copolymer and the hydride of the copolymer. The elastomer-based thermoplastic polymer here is other than the copolymer and the hydride of the copolymer. Elastomer-based thermoplastic polymers, for example, elastomer-based thermoplastic polymers including blocks other than the first block and the second block.

The olefin-based thermoplastic polymer is not particularly limited as long as it is used as an olefin-based thermoplastic polymer in a hot melt adhesive. Examples of the olefin-based thermoplastic polymer include polyolefin compounds that are solid at room temperature and polymerized with a Ziegler-Natta catalyst or a single-site catalyst. Specific examples of the olefin-based thermoplastic polymer include polyethylene, polypropylene, poly-1-butene, polyisobutylene, random copolymer or block in any ratio of propylene and at least one of ethylene and 1-butene. Copolymer, ethylene-propylene-diene terpolymer in any ratio of ethylene, propylene and diene component, random copolymer or block copolymer of ethylene or propylene and vinyl compound, random polypropylene, block polypropylene , Homopolypropylene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-octene copolymer, propylene / ethylene copolymer, propylene / ethylene / α -Butene copolymers, -Butene homopolymer, 1-butene / ethylene copolymer, 1-butene / propylene copolymer, propylene / 1-butene copolymer, ethylene / vinyl acetate copolymer, ethylene / methacrylic acid copolymer, ethylene -A methyl methacrylate copolymer etc. are mentioned. As the olefin-based thermoplastic polymer, for example, among the compounds exemplified above, an olefin-based polymer polymerized using an olefin (alkene) such as an α-olefin as a monomer is preferable. Specific examples of the olefin polymer include poly α-olefin polymers. More specifically, the poly α-olefin polymer is preferably an amorphous poly α-olefin polymer (APAO) or a homopolymer of propylene (propylene homopolymer). More specifically, the propylene homopolymer is preferably a propylene homopolymer obtained by polymerizing propylene using a metallocene catalyst.

The EVA-based thermoplastic polymer is not particularly limited as long as it is used as an EVA-based thermoplastic polymer in a hot melt adhesive, and examples thereof include a copolymer synthesized from ethylene and vinyl acetate. It is done.

The polyester-based thermoplastic polymer is not particularly limited as long as it is used as a polyester-based thermoplastic polymer in the hot melt adhesive. Examples of the polyester-based thermoplastic polymer include polyester polymerized using dimer acid as a monomer.

The polyamide-based thermoplastic polymer is not particularly limited as long as it is used as a polyamide-based thermoplastic polymer in the hot melt adhesive, and examples thereof include polyamide.

The polyacrylic thermoplastic polymer is not particularly limited as long as it is used as a polyacrylic thermoplastic polymer in a hot melt adhesive, and examples thereof include polyacrylic acid esters and polymethacrylic acid esters. Can be mentioned.

As the other thermoplastic polymer, the above-exemplified thermoplastic polymers may be used alone or in combination of two or more.

The weight average molecular weight of the thermoplastic polymer such as the copolymer varies depending on the kind of the thermoplastic polymer and is not particularly limited. For example, it is preferably 10,000 to 500,000, and is 50,000 to 300,000. It is more preferable. If the molecular weight of the thermoplastic polymer is too small, the cohesive force tends to decrease, and the stability over time tends to decrease. On the other hand, when the molecular weight of the thermoplastic polymer is too large, the melt viscosity increases and the coatability tends to decrease. In addition, the weight average molecular weight here should just be the weight average molecular weight measured by the general measuring method, for example, the weight average molecular weight measured using gel permeation chromatography (GPC) etc. are mentioned.

The tackifier used in the present embodiment is not particularly limited as long as it is a tackifier generally used for hot melt adhesives. Examples of tackifiers include rosin resins, terpene resins, and petroleum resins.

Examples of the rosin resin include natural rosin such as gum rosin, tall rosin and wood rosin, disproportionated rosin, polymerized rosin, glycerin ester and pentaerythritol ester of these rosins. Further, the rosin resin may be one in which each of the rosin resins is not hydrogenated, or hydrogenated, that is, a hydrogenated product (hydride) of the rosin resin. Also good.

Examples of the terpene resin include terpene resins, hydrocarbon-modified terpene resins, aromatic-modified terpene resins, and phenol-modified terpene resins. The terpene resin may be one in which each of the terpenes is not hydrogenated, or one obtained by hydrogenation, that is, a hydrogenated product (hydride) of the terpene resin. . The terpene resin is preferably an aromatic modified terpene resin hydride, an aromatic modified terpene resin, or a terpene resin hydride, and more preferably an aromatic modified terpene resin hydride.

Examples of the petroleum resins include aliphatic petroleum resins, alicyclic petroleum resins, aromatic petroleum resins, and hydrogenated products (hydrides) thereof. Further, as the petroleum resin hydride, an aliphatic petroleum resin hydride, an alicyclic petroleum resin hydride, and an aromatic petroleum resin hydride are preferable. Examples of the alicyclic petroleum resin hydride include hydrogenated C9 petroleum resin and hydrogenated dicyclopentadiene petroleum resin.

The tackifier preferably includes an acid-modified tackifier modified with at least one of carboxylic acid and carboxylic anhydride. The acid-modified tackifier is not particularly limited as long as it is obtained by modifying a tackifier generally used as a tackifier in a hot melt adhesive with at least one of carboxylic acid and carboxylic anhydride. As the acid-modified tackifier, for example, at least one of carboxylic acid and carboxylic acid anhydride is obtained by grafting to a tackifier, or when a tackifier is synthesized by polymerization, Examples include tackifiers obtained by copolymerizing at least one of carboxylic acid and carboxylic acid anhydride.

The tackifier before modification is not particularly limited as long as it is a tackifier generally used for hot melt adhesives, and examples thereof include the tackifiers described above.

The carboxylic acid used for the acid modification is not particularly limited. Examples of the carboxylic acid used for the acid modification include maleic acid, fumaric acid, succinic acid, phthalic acid, glutaric acid, itaconic acid, acrylic acid, and methacrylic acid.

The carboxylic acid anhydride used for the acid modification is not particularly limited. Examples of the carboxylic acid anhydride used for the acid modification include maleic anhydride (maleic anhydride), succinic anhydride, phthalic anhydride, and glutaric anhydride.

As the carboxylic acid, maleic acid, fumaric acid, and acrylic acid are preferable, and maleic acid is more preferable. The carboxylic acid anhydride is preferably maleic anhydride. Moreover, as what is used for the said acid modification, maleic anhydride which is a carboxylic acid anhydride is preferable.

As the carboxylic acid and the carboxylic acid anhydride, the above carboxylic acids and carboxylic acid anhydrides may be used alone or in combination of two or more.

Moreover, as the tackifier, the tackifiers and acid-modified tackifiers exemplified above may be used alone, or two or more kinds may be used in combination.

The softener used in the present embodiment is not particularly limited as long as it is a softener generally used for hot melt adhesives. Examples of the softener include oils such as mineral oils, synthetic oils, vegetable oils, and fatty acid esters.

Specific examples of the mineral oil include process oil and liquid paraffin. The process oil is an oil generally used as a plasticizer such as rubber or thermoplastic elastomer, and is produced in so-called petroleum refining. The process oil is generally a mixture containing an aromatic ring, a naphthene ring, and a paraffin chain, and is roughly classified into a paraffinic process oil, a naphthenic process oil, and an aromatic process oil. Process oils are those in which the number of carbon atoms in the paraffin chain occupies 50% or more of the total number of carbons, paraffin type, in which the naphthene ring carbon number occupies 30% or more, naphthenic type, and in which the aromatic carbon number occupies 30% or more. Differentiated from aromatic. Examples of the paraffinic process oil include paraffinic compounds having 4 to 155 carbon atoms, preferably paraffinic compounds having 4 to 50 carbon atoms. Specific examples of the paraffinic process oil include butane, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosan, heneicosane, docosane, tricosane. , Tetracosane, pentadecosan, hexacosane, heptacosane, octacosane, nonacosan, triacontane, hentriacontan, dotriacontan, pentatriacontane, hexacontane, and hempacontan, etc. n-paraffin, isobutane, isopentane, neopentane, isohexane, isopentane , Neohexane, 2,3-dimethylbutane, various methylhexane, 3-ethylpentane, various dimethylpentane, 2,2,3- Limethylbutane, 3-methylheptane, various dimethylhexanes, various trimethylpentanes, isononane, 2-methylnonane, isodecane, isoundecane, isododecane, isotridecane, isotetradecane, isopentadecane, isooctadecane, isonanodecane, isoeicosane, and 4-ethyl-5- Examples thereof include isoparaffins such as methyloctane and derivatives of these saturated hydrocarbons. These selected paraffinic compounds can be used in a mixture and are liquid at room temperature.

Specific examples of synthetic oils include phosphate esters, chlorinated paraffins, ethylene-α-olefin oligomers, polybutenes, low molecular weight polybutadienes, polyisoprenes, and hydrogenated products thereof that are liquid at room temperature. .

Specific examples of vegetable oils include olive oil, carnauba wax, rice germ oil, corn oil, sasanqua oil, camellia oil, castor oil, jojoba seed oil, and eucalyptus leaf oil.

Specific examples of the fatty acid esters include isopropyl myristate, octyldodecyl ristylate, glycerin triisooctanoate, diisopropyl adipate, diethyl sebacate, cetyl ethylhexanoate, cetyl palmitate, ethylhexyl palmitate, isopropyl palmitate, Examples include medium chain fatty acid triglycerides, ethylene glycol salicylate, and glycol distearate.

The softener preferably contains an acid-modified softener modified with at least one of carboxylic acid and carboxylic anhydride. The acid-modified softener is not particularly limited as long as it is obtained by modifying a softener generally used as a softener in a hot melt adhesive with at least one of carboxylic acid and carboxylic anhydride. Examples of the acid-modified softening agent include oil having a succinic acid skeleton in the molecule.

The softener before modification is not particularly limited as long as it is a softener generally used for hot melt adhesives, and examples thereof include the softeners described above.

Further, as the softener, the above-exemplified softener and acid-modified softener may be used alone or in combination of two or more.

In the hot melt adhesive, the contents of the thermoplastic polymer, the tackifier, and the softener are not particularly limited as long as they do not hinder the desired properties of the present invention. As said each content, the following ranges are mentioned, for example.

The content of the thermoplastic polymer is preferably 10 to 50 parts by weight, more preferably 15 to 30 parts by weight, and more preferably 15 to 25 parts by weight with respect to 100 parts by weight of the hot melt adhesive. More preferably it is. When the content of the thermoplastic polymer is too small, the cohesive force tends to be insufficient. Moreover, when there is too much content of the said thermoplastic polymer, there exists a tendency for melt viscosity to rise and for coating property to fall. In addition, this content is content with respect to the hot-melt-adhesive whole quantity.

The content of the tackifier is preferably 40 to 80 parts by mass, more preferably 50 to 70 parts by mass, and 55 to 65 parts by mass with respect to 100 parts by mass of the hot melt adhesive. More preferably it is. When there is too little content of the said tackifier, there exists a tendency for adhesive force to fall and for adhesive strength to fall. Moreover, when there is too much content of the said tackifier, a softness | flexibility and flexibility will be lost, there exists a tendency for stress dispersibility to fall and for holding power to fall. In addition, this content is content with respect to the hot-melt-adhesive whole quantity.

In addition, the content of the softening agent is preferably 15 to 30 parts by mass, more preferably 15 to 27 parts by mass, and more preferably 18 to 27 parts by mass with respect to 100 parts by mass of the hot melt adhesive. It is more preferable that When the content of the softening agent is too small, the creep strength when wet tends to decrease. Moreover, when there is too much content of the said softener, there exists a tendency for cohesion force and adhesive force to fall and for holding power to fall. In addition, this content is content with respect to the hot-melt-adhesive whole quantity.

For these reasons, it is preferable that the content of the thermoplastic polymer in the hot melt adhesive is 10 to 50% by mass with respect to the total amount of the hot melt adhesive. The content of the tackifier is preferably 40 to 80% by mass with respect to the total amount of the hot melt adhesive. Further, the content of the softening agent is preferably 15 to 30% by mass with respect to the total mass.

The hot melt adhesive according to the present embodiment may contain a material other than the thermoplastic polymer, the tackifier, and the softener, as long as the desired properties of the present invention are not impaired. . Specifically, addition of antioxidants, heat stabilizers, light stabilizers, UV absorbers, fillers, surfactants, coupling agents, colorants, antistatic agents, flame retardants, waxes, plasticizers, etc. An agent may be contained.

Also, examples of the antioxidant include phenolic antioxidants and organic sulfur antioxidants. Examples of phenolic antioxidants include 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2 -Tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxy Phenyl) propionate] methane and the like. Examples of organic sulfur-based antioxidants include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, and pentaerythris. Lithyltetrakis (3-lauryl thiopropionate) and the like can be mentioned. As these antioxidants, the above-exemplified antioxidants may be used alone or in combination of two or more.

The wax is not particularly limited as long as it is a wax contained in the hot melt adhesive. Examples of the wax include synthetic wax, petroleum wax, and natural wax. Examples of synthetic waxes include polyolefin waxes such as Fischer-Tropsch wax, polyethylene wax, and polypropylene wax. Examples of petroleum waxes include paraffin wax, microcrystalline wax, and petratam. Examples of natural waxes include montan wax, wood wax, carbana wax, beeswax, and castor wax. These waxes may be used alone or in combination of two or more.

The method for producing the hot melt adhesive according to the present embodiment is not particularly limited as long as it is a production method capable of producing the hot melt adhesive having the above configuration. Examples of a method for producing a hot melt adhesive include a method in which components constituting the hot melt adhesive are heated and melted and stirred and kneaded. By doing so, a hot melt adhesive having a high dispersibility of components constituting the hot melt adhesive can be obtained. Moreover, as an apparatus which implement | achieves this method, the stirring kneader, roll, Banbury mixer, kneader, extruder, etc. which were equipped with the heating apparatus are mentioned, for example.

The bonding method using the hot melt adhesive is not particularly limited as long as it can be used as the bonding method using the hot melt adhesive. As an adhesion method using a hot melt adhesive, for example, a hot melt adhesive is melted by heating. And the hot-melt-adhesive of the molten state is apply | coated to the to-be-adhered body which is a bonding target object. By leaving the other adherend in contact with the applied hot melt adhesive, the hot melt adhesive is cooled and solidified. This solidified hot melt adhesive bonds adherends to each other.

The method for applying the hot melt adhesive is not particularly limited as long as the hot melt adhesive can be suitably applied to the adherend. This coating method is roughly classified into, for example, a contact coating method and a non-contact coating method. The contact coating method refers to a coating method in which a hot melt adhesive is applied in a state where an apparatus used for coating such as a coating machine is in contact with an adherend. In addition, the non-contact coating method refers to a coating method in which a coating machine or the like is applied without being in contact with an adherend when a hot melt adhesive is applied. Examples of the contact coating method include slot coating (such as a slot coat gun manufactured by Nordson Corporation) and roll coater coating. In addition, as non-contact coating methods, for example, spiral coating that can be applied in a spiral shape (such as a spiral spray nozzle manufactured by Suntool Co., Ltd.), spray coating that can be applied in a corrugated shape (such as OMEGA COAT manufactured by ITW Dynatech Co., Ltd.) , Spray coating that can be applied in the form of a surface (curtain spray head manufactured by Suntool Co., Ltd.), dot coating that can be applied in the form of dots, etc. The hot melt adhesive according to this embodiment is suitable for spiral coating. Spiral coating is a method in which an adhesive is spirally contacted with air by intermittent or continuous coating.

This specification discloses various modes of technology as described above, and the main technologies are summarized below.

According to such a configuration, it is possible to provide a hot melt adhesive that can sufficiently suppress the occurrence of a creep phenomenon in a wet state and has excellent adhesiveness in a wet state. Therefore, this hot melt adhesive is excellent in adhesiveness in a wet state.

In the hot melt adhesive, the vinyl aromatic hydrocarbon is preferably styrene, and the conjugated diene compound is preferably at least one of butadiene and isoprene.

According to such a configuration, a hot melt adhesive that can further suppress the occurrence of a creep phenomenon in a wet state can be obtained.

In the hot melt adhesive, the tackifier preferably includes an acid-modified tackifier modified by at least one of carboxylic acid and carboxylic anhydride.

According to such a configuration, it is possible to sufficiently suppress the occurrence of the creep phenomenon in the wet state, and further, it is possible to obtain a hot melt adhesive having a further increased adhesive strength in the wet state.

In the hot melt adhesive, it is preferable that the softener includes an acid-modified softener modified with at least one of carboxylic acid and carboxylic anhydride.

According to the present invention, it is possible to provide a hot melt adhesive that can sufficiently suppress the occurrence of a creep phenomenon in a wet state and has excellent adhesion in a wet state.

Hereinafter, the present invention will be described more specifically with reference to examples, but the scope of the present invention is not limited thereto.

First, each component used in preparing the hot melt adhesive in this example will be described.

[Thermoplastic polymer]
Thermoplastic polymer 1: Styrene-isoprene-styrene block copolymer (SIS) (Quantac 3433 manufactured by Nippon Zeon Co., Ltd., styrene (second block) content: 16 mass%, diblock body content: 60 mass%)
Thermoplastic polymer 2: Styrene-isoprene-styrene block copolymer (SIS) (Global Changen 5517, Lee Chang-Ei Chemical Co., Ltd., styrene (second block) content: 15% by mass, diblock body content: 38% by mass)
Thermoplastic polymer 3: Styrene-butadiene-styrene block copolymer (SBS) (branched SBS, TR2830 manufactured by JSR Corporation, content of styrene (second block): 20% by mass, content of diblock body: 27 mass%)
Thermoplastic polymer 4: Styrene-butadiene-styrene block copolymer (SBS) (linear SBS, styrene (second block) content: 16 mass%, diblock body content: 16 mass%)
Thermoplastic polymer 5: Styrene-butadiene-styrene block copolymer (SBS) (Tahprene 315P manufactured by Asahi Kasei Corporation, content of styrene (second block): 20% by mass, content of diblock: 0% by mass)
Thermoplastic polymer 6: Styrene-butadiene-styrene block copolymer (SBS) (ASAPRENE T-438 manufactured by Asahi Kasei Corporation, content of styrene (second block): 35% by mass, content of diblock: 65% by mass )
Thermoplastic polymer 7: Styrene-butadiene-styrene block copolymer (SBS) (Asaprene T-436 manufactured by Asahi Kasei Corporation, content of styrene (second block): 30% by mass, content of diblock: 50% by mass )
Thermoplastic polymer 8: Styrene-butadiene-styrene block copolymer (SBS) (Asaprene T-420 manufactured by Asahi Kasei Corporation, content of styrene (second block): 30% by mass, content of diblock: 10% by mass )
Thermoplastic polymer 9: styrene-butadiene-styrene block copolymer (SBS) (Asaprene T-413 manufactured by Asahi Kasei Corporation, content of styrene (second block): 30% by mass, content of diblock: 75% by mass )
Thermoplastic polymer 10: styrene-butadiene-styrene block copolymer (SBS) (D-1118 made by Kraton, content of styrene (second block): 30% by mass, content of diblock body: 65% by mass)

Here, the content of styrene corresponds to the content of the second block made of a vinyl aromatic hydrocarbon in the case of the thermoplastic polymer. The content of the diblock body corresponds to the content of the diblock body of the first block made of a conjugated diene compound and the second block made of a vinyl aromatic hydrocarbon.

[Tackifier]
Tackifier: alicyclic petroleum resin hydride (hydrogenated C9 petroleum resin) (ALCON M-100 manufactured by Arakawa Chemical Industries, Ltd.)
Acid-modified tackifier: A maleic acid-modified tackifier resin produced as follows: In a reaction vessel made of stainless steel (SUS), an aromatic-modified terpene resin hydride that is a tackifier (manufactured by Yasuhara Chemical Co., Ltd.) 750 g) (Clearon K4100: softening point 100 ° C.) was added and melted at 170 ° C. Thereafter, the inside of the reaction kettle was placed in a nitrogen atmosphere, and 22.5 g of maleic anhydride, 5 g of dicumyl peroxide, and 22.5 g of butyl methacrylate were added dropwise to the melt in the reaction kettle over 1 hour. After completion of the dropwise addition, the mixture was stirred at 170 ° C. for 30 minutes, and then the reaction vessel was depressurized to remove unreacted substances and low molecular weight compounds in which dicumyl peroxide was decomposed for 1 hour. By doing so, a pale yellow solid was obtained. This solid is an aromatic-modified terpene resin hydride modified with maleic anhydride and an acid-modified tackifier (maleic acid-modified tackifier resin). The obtained acid-modified tackifier had a melt viscosity of 3500 mPa · s at 140 ° C. and a weight average molecular weight of 1260.

[Softener]
Oil: Oil (Diana Fresia S32 manufactured by Idemitsu Kosan Co., Ltd.)
Acid-modified oil: Maleic acid-modified oil (oil having a succinic acid skeleton in the molecule) (AS-1532 manufactured by Seiko PMC Co., Ltd.)

[Additive]
Wax: (Sarawax SX-105 manufactured by Evonik)
Antioxidant: Primary antioxidant (Irganox 1010 manufactured by BASF)

[Method for producing hot melt adhesive]
The above components were kneaded according to the following procedure so as to obtain the blending amounts (composition: parts by mass) shown in Table 1 below to prepare a hot melt adhesive. A tackifier, a softener, and an additive were put into a stirring kneader, and the mixture was sufficiently melted by stirring while being heated to 150 to 190 ° C. The thermoplastic polymer was charged into the melt and kneaded while being heated to 150 to 190 ° C., so that the thermoplastic polymer was sufficiently melted and uniformly dispersed in the melt. . Thereafter, an acid-modified tackifier was added into the melt and stirred and kneaded. At that time, kneading was performed as much as possible until the uniformity of the hot melt adhesive was increased. By doing so, a hot melt adhesive was produced.

[Evaluation]
(Coating property: melt viscosity)
The melt viscosity at 140 ° C. of the hot melt adhesive before curing was measured as follows. Specifically, based on the measurement method described in JIS K 6682, the viscosity of the melt of the hot melt adhesive melted at 140 ° C. was measured with a Brookfield viscometer (spindle No. 27 rotor). . This viscosity is the melt viscosity at 140 ° C. of the hot melt adhesive before curing.

Also, the melt viscosity at 160 ° C. of the hot melt adhesive before curing was measured by the same method.

(Low speed peel strength when wet)
After the manufactured hot melt adhesive is melted by heating to 150 ° C., the melted hot melt adhesive becomes 6 gsm (g / m ² ) on one side of the tissue by spiral spray. It was applied as follows. One second after application, a tissue was placed on the tissue to which the hot melt adhesive was applied so that the hot melt adhesive was in contact with the tissue. Thereafter, the tissue and the tissue were pressed at 23 ° C. and a pressure of 50 gf / cm ² for 0.01 seconds. The laminate was cut into 25 mm in the direction perpendicular to the base material (CD) to make a strip-shaped test piece. The test piece was immersed in tap water at 50 ° C. for 5 to 6 seconds, then taken out of the water and wiped off to obtain a wet test specimen. Three test specimens were prepared for each hot melt adhesive. Then, a T-type peel test based on JIS K6845 was performed on this test body. Specifically, the strength (N / 25 mm) when this specimen was peeled at a tensile speed of 10 mm / min was measured. This peel test was performed at 23 ° C. and 65% RH.

Also, as a result of this peel test, if the tissue is totally torn, it is evaluated as “◎”, and if the tissue is partially torn, it is evaluated as “○”, and the tissue is not torn. Was evaluated as “×”. In addition, when a tissue is torn, it corresponds to the material destruction which destroys a test piece, and shows that it is excellent in adhesiveness. In this case, the occurrence of the creep phenomenon in the wet state can be sufficiently suppressed, and the adhesiveness in the wet state is excellent. Moreover, when the tissue was not torn, it corresponds to interface fracture in which the test piece peels without being broken from the interface with the adhesive layer, indicating that the adhesiveness is poor.

(Shear strength when wet)
After the manufactured hot melt adhesive was melted by heating to 150 ° C., the melted hot melt adhesive was applied to 4 gsm (g / m ² ) on one surface of the foamed urethane sheet by a coater. It applied so that it might become. One second after application, a non-woven fabric was placed on the foamed urethane sheet coated with the hot melt adhesive so that the hot melt adhesive was in contact. Thereafter, the urethane foam sheet and the nonwoven fabric were pressed at 23 ° C. and a pressure of 50 gf / cm ² for 0.01 seconds. The laminate was cut into 25 mm in the direction perpendicular to the base material (CD) to make a strip-shaped test piece. The test piece was immersed in tap water at 40 ° C. for 5 to 6 seconds, then taken out of the water and wiped off to obtain a wet test specimen. Three test specimens were prepared for each hot melt adhesive. Then, a T-type peel test based on JIS K6845 was performed on this test body. Specifically, the strength (N / 25 mm) when this specimen was peeled at a tensile speed of 100 mm / min was measured. This peel test was performed at 23 ° C. and 65% RH.

As a result of this peel test, when the foamed urethane sheet was torn as a whole, it was evaluated as “◎”, and when the foamed urethane sheet was partially torn, it was evaluated as “◯”, and the urethane foam sheet was evaluated. When the sheet was not torn, it was evaluated as “x”. In addition, when a foaming urethane sheet is torn, it corresponds to the material destruction by which a test piece is destroyed, and shows that it is excellent in adhesiveness. In this case, the occurrence of the creep phenomenon in the wet state can be sufficiently suppressed, and the adhesiveness in the wet state is excellent. Moreover, when a urethane foam sheet was not torn, it corresponds to the interface fracture which peels without a test piece being destroyed from the interface with an adhesive bond layer, and shows that it is inferior to adhesiveness.

Each evaluation result is shown in Table 1 together with the blending amount of the hot melt adhesive. In Table 1, the ratio of the copolymer in the thermoplastic polymer represents the total ratio (mass%) of the thermoplastic polymers 1 to 4 with respect to the total amount of the thermoplastic polymer. Moreover, content of the softener with respect to 100 mass parts of hot-melt-adhesives shows the mass part of softener with respect to 100 mass parts of hot-melt-adhesives.

As can be seen from Table 1, the first block made of a conjugated diene compound and the second block made of a vinyl aromatic hydrocarbon, the content of the second block being less than 30% by mass, A thermoplastic polymer containing 55% by mass or more of a copolymer having a diblock body content of 1 block and the second block of 10% by mass or more is further included, and a softener is added to 100 parts by mass of the hot melt adhesive. On the other hand, in the case of the hot melt adhesive containing 15 to 30 parts by mass (Examples 1 to 9), both the low-speed peel strength when wet and the shear strength when wet are high. When measuring the shear strength, it was not the interface failure but the material failure.

On the other hand, when the thermoplastic polymer contains other than the above copolymer (Comparative Examples 3, 4, and 7), compared with Examples 1 to 9, the wet shear strength and the wet slow peel strength When measuring the low-speed peel strength when wet and when measuring the shear strength when wet, it was not a material failure but an interface failure. Further, even when the copolymer is contained, when the content of the copolymer in the thermoplastic polymer is less than 55% by mass (Comparative Examples 1, 2, and 5), it is compared with Examples 1 to 9. The wet shear strength and the low wet peel strength were low, and when measuring the wet shear strength, it was not a material failure but an interface failure.

From these facts, a thermoplastic polymer containing 55% by mass or more of a copolymer in which the content of styrene constituting the second block is less than 30% by mass and the diblock body is 10% by mass or more. By using it, it was found that the occurrence of the creep phenomenon in the wet state can be sufficiently suppressed and the adhesiveness in the wet state is excellent.

When the content of the softening agent relative to 100 parts by mass of the hot-melt adhesive is less than 15 parts by mass (Comparative Example 6), both the shear strength when wet and the low-speed peel strength when wet are low. When measuring the low-speed peel strength when wet and when measuring the shear strength when wet, it was not material failure but interface failure. Further, when the content of the softening agent with respect to 100 parts by mass of the hot melt adhesive exceeds 30 parts by mass (Comparative Example 8), compared with Examples 1 to 9, the wet shear strength is low and the wet low-speed peel strength is However, when measuring the shear strength when wet, it was not material failure but interface failure.

From these facts, a thermoplastic polymer containing 55% by mass or more of a copolymer in which the content of styrene constituting the second block is less than 30% by mass and the diblock body is 10% by mass or more. Furthermore, it was found that by containing 15 to 30% by mass of a softening agent, the occurrence of creep phenomenon in a wet state can be sufficiently suppressed, and the adhesiveness in a wet state is excellent.

From the above, the first block made of a conjugated diene compound and the second block made of vinyl aromatic hydrocarbon, the content of the second block being less than 30% by mass, the first block And a thermoplastic polymer containing 55% by mass or more of a copolymer having a diblock body content of 10% by mass or more with the second block, and further a softener with respect to 100 parts by mass of the hot melt adhesive It has been found that a hot melt adhesive containing 15 to 30 parts by mass can sufficiently suppress the occurrence of creep phenomenon in a wet state and is excellent in adhesiveness in a wet state.

This application is based on Japanese Patent Application No. 2017-114990 filed on June 12, 2017, the contents of which are included in the present application.

In order to express the present invention, the present invention has been described above and properly through the embodiments. However, those skilled in the art can easily change and / or improve the above-described embodiments. Should be recognized. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

According to the present invention, there is provided a hot melt adhesive that can sufficiently suppress the occurrence of a creep phenomenon in a wet state and has excellent adhesiveness in a wet state.

Claims

A hot melt adhesive comprising a thermoplastic polymer, a tackifier, and a softener,
The thermoplastic polymer includes at least one of a copolymer comprising a first block comprising a conjugated diene compound and a second block comprising a vinyl aromatic hydrocarbon, and a hydride of the copolymer.
The copolymer is a copolymer in which the content of the second block is less than 30% by mass and the content of the diblock body of the first block and the second block is 10% by mass or more. Yes,
The copolymer and the hydride content of the copolymer are 55% by mass or more based on the total amount of the thermoplastic polymer,
The hot-melt adhesive is characterized in that the content of the softening agent is 15 to 30 parts by mass with respect to 100 parts by mass of the hot-melt adhesive.
The vinyl aromatic hydrocarbon is styrene,
The hot melt adhesive according to claim 1, wherein the conjugated diene compound is at least one of butadiene and isoprene.
The hot-melt adhesive according to claim 1 or 2, wherein the tackifier includes an acid-modified tackifier modified with at least one of carboxylic acid and carboxylic anhydride.
The hot melt adhesive according to any one of claims 1 to 3, wherein the softener includes an acid-modified softener modified with at least one of carboxylic acid and carboxylic anhydride.