Melting bag, and massive body, hot-melt sheet and hot-melt laminate using the same

Abstract

To provide a melting bag for a hot melt adhesive, a hot melt sheet using the same, and a hot melt laminate which are more excellent in workability at the time of packing such as crushing resistance and deformation easiness than before, and further excellent in compatibility with contents at the time of use.SOLUTION: The melting bag is formed of a resinous composition containing at least a styrene-based elastomer (A) and having a melt viscosity of 30, 000mPa. s or less at 160 °C.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to melt bags, blocks, hot melt sheets, and hot melt laminates that are suitable for use in packaging hot melt adhesives. [Background technology]

[0002] Hot melt adhesives are melted and bonded to objects, and then cooled down to immediately demonstrate their adhesive properties, so the advantage of not requiring a curing period has been rediscovered, and their use in packaging and industrial applications is expanding. In addition, with the recent social change that emphasizes reducing the burden on the environment, the advantage of not requiring solvents or drying processes during use has also been rediscovered, and their use is continuing to expand.

[0003] As the range of applications for hot melt expands, improvements in workability are required. In the summer, lumps of hot melt tend to stick together (blocking), forming huge lumps when removed from packaged cardboard boxes, etc., significantly reducing workability. In particular, hot melt adhesives that remain adhesive at room temperature are packed, transported, and stored wrapped in release paper or film, which is then peeled off and discarded when the hot melt is used. However, the disposal of these release materials has also come to be seen as an environmental burden.

[0004] To address this issue, a so-called melt bag was developed, in which the hot melt is packaged in a hard material and melted while still wrapped when in use (Patent Document 1). This avoids the environmental burden of discarding release material and eliminates the need to peel off the release material every time a block of hot melt is melted, dramatically improving work efficiency.

[0005] In recent years, measures to prevent blocking have been taken, such as increasing the strength of the melting bag (Patent Document 2) or embossing the shape (Patent Document 3). However, these methods have a significant discrepancy with the properties of the hot melt contained therein, resulting in insufficient compatibility between the melting bag and the hot melt in the melting furnace, and the mixed molten material supplied to the coating head not being in the designed ratio. Furthermore, because the strength of the melting bag is too high, when a mass of hot melt adhesive wrapped in the melting bag is packaged in a cardboard box or the like, the mass is unable to change shape, resulting in a package with a low density and a lower filling capacity than desired. However, if the strength of the melting bag is made too weak to impart deformability, the mass breaks during packaging, exposing the hot melt adhesive to the surface, resulting in the problem of blocking between the masses.

[0006] An example of a hot melt adhesive that exhibits adhesiveness at room temperature is a hot melt adhesive used for labels attached to PET bottles. To recycle PET bottles, the bottles must be immersed in a heated alkaline aqueous solution to separate the labels from the bottles. Therefore, alkaline dispersibility is required for hot melt adhesives for PET bottle labels. Since contamination is undesirable in food and beverage applications, sufficient compatibility between the melting bag and the alkaline dispersible hot melt is required. The inventors' investigations revealed that conventional melting bags had issues with compatibility with alkaline dispersible hot melts. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-002581 [Patent Document 2] International Publication No. 2014 / 194087 [Patent Document 3] Japanese Patent Application Publication No. 2019-065164 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, an object of the present invention is to provide a melting bag that is superior to conventional bags in terms of workability during packaging, such as shatter resistance and ease of deformation, and that also has excellent compatibility with the contents during use, and that is suitable for use in packaging hot melt adhesives, as well as a mass, hot melt sheet, and hot melt laminate that use the same. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems and have completed the present invention. That is, an embodiment of the present invention is a melt bag containing at least a styrene-based elastomer (A) and having a melt viscosity at 160°C of 30,000 mPa·s or less.

[0010] Another embodiment of the present invention is the melt bag, wherein the content of the styrene elastomer (A) is 70% by mass or less in 100% by mass of the resin composition forming the melt bag.

[0011] Another embodiment of the present invention is the melt bag described above, which contains at least a styrene-ethylene-butylene-styrene block copolymer as the styrene-based elastomer (A).

[0012] Another embodiment of the present invention is the melt bag described above, wherein the styrene elastomer (A) has a weight average molecular weight of 300,000 or less.

[0013] Another embodiment of the present invention is the melt bag, which is for packaging hot melt adhesives.

[0014] Another embodiment of the present invention is a mass in which a hot melt adhesive is packaged in a melt bag, the melt bag being the above-mentioned melt bag.

[0015] Another embodiment of the present invention is the above-mentioned mass, wherein the difference between the softening point of the hot melt adhesive and the softening point of the melting bag is within 50°C.

[0016] Another embodiment of the present invention is a hot melt sheet, which is a sheet-shaped product of the above-mentioned mass.

[0017] Another embodiment of the present invention is the hot melt sheet, wherein the ball tack at a thickness of 25 μm is 4 or more.

[0018] Another embodiment of the present invention is a hot melt laminate in which the hot melt sheet and an adherend are arranged in this order. [Effects of the Invention]

[0019] The present invention as described above makes it possible to provide a melting bag suitable for use in packaging hot melt adhesives, which has superior workability during packaging, such as shatter resistance and ease of deformation, and which also has excellent compatibility with the contents during use, as well as a mass, hot melt sheet, and hot melt laminate using the same. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic cross-sectional view partially showing a mass of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, a melt bag and a hot melt adhesive bag that are preferably used for packaging the hot melt adhesive of the present invention will be described. The meltsheet and hot melt laminate will now be described in more detail, but without limitation. The melting bag containing the hot melt adhesive is called a mass. Note that the term "hot melt adhesive" includes hot melt pressure sensitive adhesives. In this specification, a numerical range specified using "to" includes the numerical values ​​before and after "to" as the lower and upper limit values. In this specification, hot melt adhesives may be abbreviated as "hot melt." Unless otherwise noted, the various components appearing in this specification may be used independently either alone or in combination of two or more. Furthermore, "parts" and "%" represent "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0022] <Melting bag> The melting bag of the present invention is preferably used for packaging hot melt adhesives, but is not limited to this, as long as it can contribute technically to products other than hot melt adhesives. The melting bag can be produced by heating and melting a material (resin composition) containing at least the styrene-based elastomer (A), and forming (producing) a film using a known method.

[0023] The melt viscosity (mPa·s) of the melting bag at 160°C is 30,000 or less, preferably 25,000 or less, and more preferably 20,000 or less. Preferably, it is 1,000 or more, more preferably 2,000 or more, and even more preferably 3,000 or more. Although the influence of the film thickness must also be taken into consideration, by having the melt viscosity within the above range, it is easy to achieve both crush resistance and compatibility. In this specification, the melt bag and the resin composition differ in whether or not they are film-formed, but are otherwise identical, so the preferred properties of the melt bag can be interpreted as the properties of the resin composition.

[0024] The softening point of the melting bag is preferably 50° C. or higher, more preferably 60° C. or higher, even more preferably 70° C. or higher, particularly preferably 80° C. or higher, and most preferably 95° C. or higher. Also, it is preferably 150° C. or lower, more preferably 130° C. or lower, even more preferably 110° C. or lower, and particularly preferably 100° C. or lower. When the softening point is within the above range, shatter resistance and blocking resistance are easily exhibited. The softening point is measured in accordance with JIS K-2207 (petroleum asphalt) 6.4 softening point test method (ring and ball method).

[0025] The thickness of the melting bag is preferably 25 to 500 μm, more preferably 50 to 500 μm, even more preferably 50 to 300 μm, and particularly preferably 50 to 200 μm. When the thickness is within the above range, it is easy to achieve both crush resistance and ease of deformation.

[0026] The amount of volatile organic compounds (VOCs) contained in the melting bag is preferably 3% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and preferably substantially zero. By keeping the amount of VOCs within this range, the melting bag is easily suitable for applications where hygiene is important, such as the food and medical industries.

[0027] ≪Resin composition≫ In the present invention, the resin composition refers to a material for forming a melt bag, and contains at least a styrene-based elastomer (A). It is preferable that the resin composition further contains a process oil (B) and a tackifier (C). The inclusion of the process oil (B) provides excellent compatibility and ease of deformation, and the inclusion of the tackifier (C) provides excellent resistance to crushing, which is preferable.

[0028] <Styrene-based elastomer (A)> Styrenic elastomer (A) is a type of thermoplastic elastomer. Thermoplastic elastomers are elastic materials that have properties similar to vulcanized rubber at room temperature, and at high temperatures, they are polymeric materials that can be molded using existing molding machines, just like ordinary thermoplastic resins. Thermoplastic elastomers have properties that are intermediate between rubber and plastic, as they contain both elastic rubber components (soft segments: soft phase) in the molecule and molecular restraint components (hard segments: hard phase) that prevent plastic deformation. Styrene elastomers generally have a polystyrene block and a rubber mid-block, with the polystyrene portion forming physical cross-links (domains) and becoming cross-linking points, and the middle rubber block giving the product rubber elasticity. The middle soft segment includes polybutadiene (B), polyisoprene (I) and polyolefin elastomers (ethylene-propylene (EP), ethylene-butylene (EB), butylene-butadiene (BB)), and the hard Depending on the arrangement of the segments with polystyrene (S), they are divided into linear and branched types.

[0029] Examples of styrene-based elastomers include styrene-butadiene-styrene block copolymer (hereinafter sometimes abbreviated as SBS), styrene-ethylene-butylene-styrene block copolymer (including hydrogenated SBS, hereinafter sometimes abbreviated as SEBS), styrene-ethylene-propylene-styrene block copolymer (hereinafter sometimes abbreviated as SEPS), styrene-isoprene-styrene block copolymer (hereinafter sometimes abbreviated as SIS), styrene-butylene-butadiene-styrene block copolymer (hereinafter sometimes abbreviated as SBBS), etc. Among these, from the viewpoint of crush resistance, it is preferable to contain styrene-ethylene-butylene-styrene block copolymer or styrene-butylene-butadiene-styrene block copolymer, and it is even more preferable to contain styrene-ethylene-butylene-styrene block copolymer.

[0030] The styrene content of the styrene elastomer (A) is preferably 10 to 50% by mass, more preferably 15 to 45% by mass, and even more preferably 20 to 40% by mass. A styrene content within this range makes it easier to balance the strength required to exhibit crush resistance with the flexibility required to exhibit ease of deformation. The styrene content is the content (% by mass) of styrene in 100% by mass of the styrene elastomer.

[0031] The weight average molecular weight (Mw) of the styrene elastomer (A) is preferably 10,000 to 300,000, more preferably 50,000 to 200,000, further preferably 80,000 to 150,000, and particularly preferably 100,000 to 150,000. By setting the molecular weight within the above range, it is easy to achieve both high crush resistance and ease of deformation. The weight average molecular weight is a value calculated as polystyrene measured by gel permeation chromatography (GPC).

[0032] The content of the styrene elastomer (A) is preferably 1 to 70 mass%, more preferably 3 to 60 mass%, still more preferably 5 to 50 mass%, and particularly preferably 10 to 45 mass%, based on 100 mass% of the resin composition. By including the styrene elastomer (A) in the above range, it is easy to achieve both crush resistance and ease of deformation.

[0033] <Process oil (B)> Process oil (B) is generally used as a plasticizer for rubber, thermoplastic elastomers, etc. It is a process oil produced in petroleum refineries, etc., and is broadly classified into paraffinic process oil, aromatic process oil, and naphthenic process oil. Process oil is a mixture of paraffin chains, aromatic rings, and naphthenic rings, and is classified as paraffinic process oil when paraffin chain carbons out of the total carbons are 50% by mass or more, aromatic process oil when aromatic carbons out of the total carbons are 30% by mass or more, and naphthenic process oil when naphthenic ring carbons out of the total carbons are 30% by mass or more.

[0034] The content of the process oil (B) is preferably 5 to 90 mass %, more preferably 10 to 80 mass %, still more preferably 15 to 70 mass %, and particularly preferably 20 to 60 mass %, based on 100 mass % of the resin composition. By including the process oil (B) in the above range, excellent deformability is achieved.

[0035] <Tackifier (C)> The tackifier (C) is a polymer with a relatively low molecular weight, ranging from several hundred to several thousand. It exhibits liquid or solid properties at room temperature, and adding the tackifier imparts fluidity and tackiness, improving adhesive strength. In the present invention, there are no particular limitations on the type of tackifier, as long as it is solid at room temperature. If it is solid at room temperature, it will have excellent shatter resistance while also fulfilling its primary function of enhancing adhesive strength when used as a hot melt.

[0036] Tackifiers (C) are broadly classified into natural resin-based and synthetic resin-based. Natural resin-based compounds include rosin-based resins and terpene-based resins, while synthetic resin-based compounds include petroleum-based resins, phenol-based resins, and xylene-based resins. Either tackifier can be used alone or in combination depending on the application.

[0037] The tackifier (C) preferably contains at least one of a fully hydrogenated petroleum resin and a partially hydrogenated petroleum resin. By containing at least one of a fully hydrogenated petroleum resin and a partially hydrogenated petroleum resin, the resin has excellent resistance to crushing. Since fully hydrogenated petroleum resins and partially hydrogenated petroleum resins do not have aromatic rings that increase intermolecular affinity, they are thought to be less prone to blocking. At first glance, using a tackifier (C) in a melting bag may be perceived as being contrary to the role of the melting bag, but its use is preferred from the viewpoint of compatibility with the hot melt adhesive contained therein.

[0038] The content of the tackifier (C) is preferably from 0 to 50 mass %, more preferably from 0 to 45 mass %, and even more preferably from 5 to 40 mass %, relative to 100 mass % of the resin composition. By including the tackifier (C) in the above range, it is easy to achieve both crush resistance and ease of deformation while adjusting the amount of the process oil (B). From the viewpoint of compatibility, the content of the tackifier (C) or the process oil (B) or the total of these is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 45% by mass or more, based on 100% by mass of the resin composition.

[0039] To the extent that the problems of the present invention can be solved, waxes such as polyethylene wax, polypropylene wax, Fischer-Tropsch wax, paraffin wax, and microcrystalline wax, α-methylstyrene resin, and other thermoplastic elastomers can be used as components contained in the resin composition that forms the melt bag. Other examples of thermoplastic elastomers include olefin-based, urethane-based, polyester-based, polyamide-based, and 1,2-butadiene-based elastomers. If necessary, antioxidants, antiaging agents, etc. may be added to prevent thermal deterioration and thermal decomposition.

[0040] [Production of resin composition] The resin composition can be prepared by compounding and mixing the above-mentioned materials while heating them in a known manner. Diluting the product with an organic solvent increases workability, but limits the range of applications, so it is preferable to avoid using organic solvents whenever possible.

[0041] <Lump> The lump is a hot melt adhesive packaged in a melting bag. The weight is preferably 10 g to 5000 g. A weight within the above range is preferable because it is easy to handle and has excellent workability in terms of the number of times it can be filled. The thickness of the melting bag can be adjusted appropriately depending on the weight. After forming (manufacturing) the melting bag, a mass can be obtained by filling it with hot melt adhesive so as to minimize air getting in. From the viewpoint of energy efficiency, this process is preferably cooled immediately after film formation or carried out underwater.

[0042] (hot melt adhesive) For example, when a hot melt adhesive is intended for adhesive applications, it is preferable that the resin system contains a styrene-based elastomer, since this facilitates the development of various adhesive properties. As the styrene-based elastomer, the same materials as those used in the resin composition for manufacturing the melt bag described above can be used. In terms of compatibility in a melting furnace, it is more preferable to use the same type of material as the resin composition. Specifically, it is preferable to contain a styrene-based elastomer (A), a process oil (B), and a tackifier (C). The types of the styrene elastomer (A), the process oil (B) and the tackifier (C) can be appropriately selected depending on the application of the hot melt.

[0043] Hot melt adhesives for PET bottle labels require releasability with an alkaline aqueous solution, so the tackifier (C) preferably has a high acid value of 100 mgKOH / g or more. The upper limit of the acid value is preferably 400 mgKOH / g. The acid value of the hot melt adhesive is preferably 15 to 100 mgKOH / g. The content of the tackifier having an acid value is preferably 0.1 to 70 mass%, more preferably 1 to 60 mass%, even more preferably 15 to 55 mass%, and particularly preferably 25 to 50 mass%, based on 100 mass% of the hot melt adhesive. The higher the acid value, the lower the content can be. Furthermore, for environmentally friendly products, a tackifier with a high biomass content of 80% or more is preferred.

[0044] The softening point of the hot melt adhesive is preferably 40° C. to 110° C., more preferably 50° C. to 100° C., and even more preferably 60° C. to 90° C. Hot melt adhesives with softening points within the above range exhibit tackiness at room temperature, and therefore have excellent compatibility with melting bags while enjoying the advantages of being formed into a mass, and also tend to exhibit cohesive strength when used as a hot melt.

[0045] The difference between the softening point of the hot melt adhesive and the softening point of the melting bag is preferably within 70° C., more preferably within 50° C., even more preferably within 30° C., and particularly preferably within 20° C. When the difference is within the above range, excellent compatibility between the two is achieved.

[0046] <Hot melt sheet> The hot melt sheet is a sheet-shaped product of a lump, which can be produced by melting the lump in a melting furnace and forming it into a sheet by any coating method.

[0047] The coating method is not particularly limited, but known methods can be used. Examples include the open wheel method, the closed gun method, and the direct coating method. When emphasis is placed on removability depending on the application, the open wheel method and the direct coating method are preferred. The thickness of the hot melt sheet varies depending on the application, but is generally between 10 μm and 100 It is used at a thickness of 0 μm.

[0048] The ball tack of the hot melt sheet is not particularly limited, but for label applications such as food packaging, the ball tack at a thickness of 25 μm is preferably 4 or more. A ball tack of 4 or more is preferable because sufficient adhesive strength can be obtained. The method for measuring the ball tack is described in detail in the Examples section.

[0049] <Hot melt laminate> A hot melt laminate is a laminate in which a hot melt sheet and an adherend are arranged in this order. There are no particular limitations on the manufacturing method, but it can be obtained by (a) a method in which a hot melt is applied to the release-treated surface of a release-treated film to prepare a hot melt sheet with a release film, and then an adherend is laminated on the surface of the hot melt layer, (b) a method in which a hot melt is directly applied to the adherend, and then the release-treated surface of the release-treated film is laminated on the surface of the hot melt layer, or (c) a method in which the release film is peeled off from the laminate obtained by (a) or (b), and then an adherend is laminated on the surface of the hot melt layer.

[0050] (adherent) The adherend is not particularly limited, but plastic, nonwoven fabric, and paper can be suitably used. Examples of plastics include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), acrylic resins such as polymethyl methacrylate (PMMA), and other plastic materials such as polycarbonate, triacetyl cellulose, polysulfone, polyarylate, and polycycloolefin. Examples of nonwoven fabrics include nonwoven fabrics made of hydrophilic fibers such as cotton and rayon, and nonwoven fabrics made of synthetic resin fibers that have been subjected to a hydrophilic treatment. Examples of paper include Yupo paper, coated paper, wood-free paper, and cardboard. The adherends can be used alone or in combination of two or more.

[0051] There are no particular limitations on the uses of the hot melt laminate, but examples include food labels, hygiene products such as diapers and sanitary products, and bonding materials used in personal computers, cameras, and medical equipment. [Example]

[0052] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these. In the examples, unless otherwise specified, "parts" means "parts by mass," "%" means "% by mass," and "RH" means relative humidity. The blending amounts in the tables are in parts by mass. Blank spaces in the tables indicate that no ingredients were blended.

[0053] [Weight average molecular weight] The weight average molecular weight (Mw) was measured using a GPC "LC-GPC system" manufactured by Shimadzu Corporation. The weight average molecular weight (Mw) can be determined by conversion using polystyrene of known molecular weight as a standard substance. Device name: Shimadzu Corporation, LC-GPC system "Prominence" Columns: Four GMHXL columns manufactured by Tosoh Corporation and one HXL-H column manufactured by Tosoh Corporation were connected together. Mobile phase solvent: tetrahydrofuran Flow rate: 1.0ml / min Column temperature: 40℃

[0054] Melt Flow Rate (MFR) MFR complies with JIS.K7210 and uses the Melt Indexer L244 (Takara Kogyo Co., Ltd.). The sample was filled into a cylinder with an inner diameter of 9.55 mm and a length of 162 mm (manufactured by Co., Ltd.), and after melting at 190°C, a load was applied evenly using a plunger weighing 2160 g and having a diameter of 9.48 mm, and the amount of resin extruded per unit time (g / 10 min) was calculated from the amount of resin extruded per unit time (g / 10 min) from an orifice with a diameter of 2.1 mm located in the center of the cylinder.

[0055] The abbreviations used in Tables 1 to 4 are as follows: [Styrene-based elastomer (A)] G1642: Kraton G1642 (Kraton Polymers, SEBS, styrene) Content: 21% by mass, weight average molecular weight: 124,000) G1650: Kraton G1650 (Kraton Polymers, SEBS, styrene) Content: 30% by mass, weight average molecular weight: 96,000) A1536: Kraton A1536 (Kraton Polymers, SEBS, styrene) Content: 42% by mass, weight average molecular weight: 135,000) G1726: Kraton G1726 (Kraton Polymers, SEBS, styrene content: 30% by mass, weight average molecular weight: 46,000) D1161: Kraton D1161 (Kraton Polymers, SIS, styrene content: 15% by mass, weight-average molecular weight: 180,000)

[0056] [Process oil (B)] PW-90: Diana Process PW-90 (Idemitsu Kosan, paraffin-based process oil)

[0057] [Tackifier (C)] P-100: Alcon P-100 (manufactured by Arakawa Chemical Co., Ltd., hydrogenated petroleum resin, softening point: 100°C) Haritack F (Harima Chemicals, hydrogenated rosin, acid value: 170 mg KOH / g, softening point: 80°C)

[0058] [wax] Sasol H1 (manufactured by Sasol Chemical Industries, Fischer-Tropsch wax, softening point: 112°C) Sasol C80 (manufactured by Sasol Chemical Industries, Fischer-Tropsch wax, softening point: 88°C)

[0059] [Other thermoplastic elastomers] LDPE: Low-density polyethylene (melting peak temperature 107°C, density 0.919 g / cm 3 , MFR4g / 10min) EVA: Ethylene-vinyl acetate copolymer (vinyl acetate content 28% by mass, MFR 6g / 10min)

[0060] Example 1 <Production of Resin Composition P-1> 30 parts of Sasol H1 wax and 20 parts of PW-90 as process oil (B) were placed in a stainless steel beaker equipped with a stirrer and heated to melt. Heating was performed carefully so that the contents would reach 130-150°C. After melting, the mixture was stirred to form a homogeneous molten liquid. While maintaining the temperature at 130-150°C and continuing to stir, 10 parts of G1642 as a styrene-based elastomer (A) were added to the melt. After the addition was complete, the mixture was heated and stirred at 130-150°C until the G1642 was completely melted. Next, 40 parts of P-100 as a tackifier (C) were added to form a homogeneous molten mixture, which was then cooled to prepare resin composition P-1. After adjusting the temperature of resin composition P-1 to 160°C, a B-type viscometer (manufactured by Toki Sangyo Co., Ltd., "RB80L") and a viscometer were used. Measurement was performed at an appropriate rotation speed using rotor No. 3. The melt viscosity of resin composition P-1 at 160°C was 500 mPa·s.

[0061] <Production of Hot Melt Adhesive Q-1> Five parts of Sasol C80 wax and 40 parts of PW-90 process oil (B) were placed in a stainless steel beaker equipped with a stirrer and heated to melt. Heating was performed carefully to keep the contents at 130-150°C. After melting, the mixture was stirred to form a homogeneous molten liquid. While maintaining the temperature at 130-150°C and continuing to stir, 25 parts of G1726 (styrene elastomer (A)) were added to the molten mixture. After the addition was complete, the mixture was heated and stirred at 130-150°C until the G1726 was completely melted. Next, 30 parts of Haritack F (tackifier (C)) were added to form a homogeneous molten mixture, which was then cooled to produce hot melt adhesive Q-1. <Production of melt bag and lump 1> Next, resin composition P-1 was placed in a melt bag molding machine and set to form a melt bag with a film thickness of 200 μm at a temperature of 100° C. 500 g of hot melt adhesive Q-1 was extruded toward the melt film while heating, and the film was molded by enveloping it in water. After cooling in the water, aggregate 1 was obtained.

[0062] <Hot melt sheet manufacturing> The obtained lump 1 was melted for 1 hour in a melting furnace heated to 160°C and coated onto the release agent layer of a heavy release film so that the thickness of the sheet after formation was 25 µm to form a hot melt sheet. Next, the release agent layer of a light release film was laminated to this hot melt layer to obtain a hot melt sheet.

[0063] (Examples 2 to 20, Comparative Example 1) Hot melt adhesives (Q-2 to Q-6) were produced in the same manner as in Example 1, except that the compositions and blending amounts (parts by mass) were changed to those shown in Table 1. Resin compositions (P-2 to P-20, P'-1) were produced in the same manner as in Example 1, except that the compositions and blending amounts (parts by mass) were changed to those shown in Tables 2 to 4, and their melt viscosities at 160°C were measured. Subsequently, in the same manner as in Example 1, the hot melt was filled into a melting bag to obtain lumps and hot melt sheets of Examples 2 to 20 and Comparative Example 1. In Tables 1 to 4, melt viscosity at 160°C is abbreviated as 160°C viscosity, hot melt as HM, styrene elastomer as elastomer, process oil as oil, tackifier as TF, and wax as WAX.

[0064] [Table 1]

[0065] [Table 2]

[0066] [Table 3]

[0067] [Table 4]

[0068] <Ball tuck> The resulting hot melt sheet was prepared to a size of 25 mm wide and 250 mm long. The light-release film was peeled off from the hot melt sheet and it was fixed to an inclined plate at an angle of 30 degrees. The heavy-release film was peeled off to expose the adhesive side. A PET film for the runway was attached to the top, and a steel ball (1 / 32 to 32 / 32 inches) was rolled across the sample, which had a runway of 10 cm and an adhesive surface of 10 cm. The diameter number of the ball that stopped near the center of the adhesive surface was recorded.

[0069] <Ease of deformation> The ease of deformation (deformability) of the resulting mass was evaluated using a rubber hardness tester Type A (a durometer hardness tester manufactured by Shimadzu Corporation) according to the following criteria. [Evaluation criteria] ◎: Measurement scale is 20 points or less, excellent. 〇: Measurement scale is between 20 points and 30 points, good. △: Measurement scale is between 30 points and 40 points, no practical problems. ×: The measurement scale is over 40 points, which is problematic for practical use.

[0070] <Crush resistance> A release film was laid on a small piece of cardboard, molten hot melt adhesive was poured onto it, and the adhesive was allowed to cool and harden naturally, producing a flat-surfaced block of hot melt adhesive. A melting bag (10 cm square, 200 μm thick) was then layered on top of the resulting block of hot melt adhesive, and another melting bag (10 cm square, 200 μm thick) and block of hot melt adhesive were layered on top of that, in that order, to produce a block of hot melt adhesive / melting bag / / melting bag / block of hot melt laminate. A 10 kg weight was placed on this laminate, and it was stored at 40°C for 24 hours. After air cooling, the melting bags were manually peeled apart to evaluate shatter resistance. The evaluation criteria are as follows: [Evaluation criteria] ◎: No peeling noise or peeling strength, excellent. Good: Slight peeling noise, peel strength, good. △: Blocking occurred, but the melted bag did not break when peeled off, and there was no problem in practical use. ×: Blocking occurred and the melted bag broke when peeled off, which is problematic in practical use.

[0071] <compatibility> A white melting bag was prepared by blending 1% by mass of titanium oxide with respect to the total mass of the melting bag, and this was used to prepare a white mass. When preparing a hot melt sheet from the obtained white mass, the compatibility of the white melting bag and the hot melt adhesive in the melting furnace was evaluated based on the whiteness unevenness of the hot melt sheet. The evaluation criteria are as follows: [Evaluation criteria] ◎: No color unevenness, excellent. 〇: Good, with some color unevenness in some areas. △: Although color unevenness was observed overall, there was no remaining melted part in the melting bag, and there was no problem in practical use. ×: Color unevenness is observed overall, and melted bags remain, which is problematic for practical use.

[0072] The results in Tables 2 to 4 show that the lumps of Examples 1 to 20 have excellent workability during packaging and transportation, such as crush resistance and ease of deformation, and the melting bags have excellent compatibility with the contents when used. On the other hand, the lumps of Comparative Example 1 did not satisfy all of the above properties. [Explanation of symbols]

[0073] 1 melting bag 2. Hot melt adhesive

Claims

1. Contains at least a styrene-based elastomer (A), A melt bag having a melt viscosity of 30,000 mPa·s or less at 160°C.

2. The melt bag according to claim 1 , wherein the content of the styrene-based elastomer (A) is 70% by mass or less in 100% by mass of a resin composition forming the melt bag.

3. 3. The melt bag according to claim 1, wherein the styrene-based elastomer (A) contains at least a styrene-ethylene-butylene-styrene block copolymer.

4. 3. The melt bag according to claim 1, wherein the styrene-based elastomer (A) has a weight average molecular weight of 300,000 or less.

5. 3. The melt bag according to claim 1 or 2, which is for packaging hot melt adhesives.

6. A mass of hot melt adhesive packed in a melt bag, the melt bag being the melt bag according to claim 1 or 2.

7. 7. The mass according to claim 6, wherein the difference between the softening point of the hot melt adhesive and the softening point of the melting bag is within 50°C.

8. A hot melt sheet, which is a sheet-shaped product of the mass according to claim 6.

9. 9. The hot melt sheet according to claim 8, which has a ball tack of 4 or more at a thickness of 25 μm.

10. A hot melt laminate comprising the hot melt sheet according to claim 8 and an adherend arranged in this order.

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