Melting bag, and lump shaped body, hot melt sheet, and hot melt laminate using the same

Abstract

To provide a melting bag for a hot melt adhesive, which is superior in workability during packaging such as crushing resistance, and deformation easiness more than before, and which is also superior in compatibility with a content during use, and a hot melt sheet and a hot melt laminate using the same.SOLUTION: A melt bag is formed from a resin composition containing at least a styrene-based elastomer (A) and having a melt viscosity of 30,000 mPa 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, and the adhesive function is immediately apparent, so the advantage of not needing a curing period has been rediscovered, and their use in packaging and industrial applications is expanding. In response to recent social changes that emphasize reducing the burden on the environment, the advantage of not needing a solvent or drying process during use has also been rediscovered, and their use is continuing to expand.

[0003] As the range of application of hot melt expands, there is a demand for improved workability. In the summer, hot melt blocks stick together (blocking), and when removing them from the cardboard boxes in which they are packed, they form huge blocks, which significantly reduces workability. In particular, hot melt adhesives that are adhesive at room temperature are packed, transported, and stored wrapped in release paper or film, which is peeled off and discarded when the hot melt is to be used. However, the disposal of these release materials has also come to be seen as an environmental burden.

[0004] Therefore, a specification called a melting bag was developed in which hot melt is packaged in a hard material and the hot melt is melted while still packaged when it is used (Patent Document 1). This avoids the environmental burden of disposing of the release material, and also eliminates the work of peeling off the release material every time a lump of hot melt is melted, dramatically improving work efficiency.

[0005] In recent years, measures have been taken to prevent blocking, such as increasing the strength of the melting bag (Patent Document 2) or embossing the shape (Patent Document 3). However, these methods have a large deviation from the characteristics of the hot melt, which is the content, resulting in insufficient compatibility between the melting bag and the hot melt in the melting furnace, and the problem that the mixed melt supplied to the coating head does not reach the designed ratio. In addition, since the strength of the melting bag is too high, when packing the mass wrapped with the hot melt adhesive in the melting bag in cardboard or the like, the mass cannot change its shape, resulting in a problem of a low-density package that does not reach the desired filling amount. However, if the strength of the melting bag is extremely weakened to impart deformability, there is a problem that it is crushed during packing and the hot melt adhesive comes out to the surface, causing the masses to block each other.

[0006] As an example of a hot melt that exhibits adhesiveness at room temperature, a hot melt used for a label attached to a PET bottle can be mentioned. Since it is necessary to immerse the heated PET bottle in an alkaline aqueous solution to separate the PET bottle and the label in order to recycle the PET bottle, the hot melt for PET bottle labels is required to have alkali dispersibility. In food and beverage applications, since foreign matter contamination is disliked, sufficient compatibility between the melting bag and the hot melt having alkali dispersibility is necessary. As a result of the study by the present inventors, there were problems with the compatibility of conventional melting bags with hot melts having alkali dispersibility.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] Therefore, the present invention provides a melt bag that is superior in workability during packaging, such as crush resistance and ease of deformation, compared to the prior art, and is also superior in compatibility with the contents during use, and is suitably used for packaging hot melt adhesives, a bulk body using the same, a hot melt sheet, and a hot melt laminate.

Means for Solving the Problems

[0009] As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, an embodiment of the present invention is a melt bag containing at least a styrenic elastomer (A) and having a melt viscosity at 160 °C of 30,000 mPa·s or less.

[0010] Further, an embodiment of the present invention is the above melt bag in which the content rate of the styrenic elastomer (A) is 70 mass% or less in 100 mass% of the resin composition forming the melt bag.

[0011] Further, an embodiment of the present invention is the above melt bag containing at least a styrene-ethylene / butylene-styrene block copolymer as the styrenic elastomer (A).

[0012] Further, an embodiment of the present invention is the above melt bag in which the weight average molecular weight of the styrenic elastomer (A) is 300,000 or less.

[0013] Further, an embodiment of the present invention is the above melt bag for packaging a hot melt adhesive.

[0014] Further, an embodiment of the present invention is a bulk body in which a hot melt adhesive is packaged in a melt bag, and the melt bag is the above melt bag.

[0015] Further, an embodiment of the present invention is the above bulk body in which the difference between the softening point of the hot melt adhesive and the softening point of the melt bag is within 50 °C.

[0016] Also, an embodiment of the present invention is a hot melt sheet which is a sheet-shaped molded product of the above-mentioned massive body.

[0017] Also, an embodiment of the present invention is the above-mentioned hot melt sheet having a ball tack of 4 or more at a thickness of 25 μm.

[0018] Also, an embodiment of the present invention is a hot melt laminate in which the above-mentioned hot melt sheet and an adherend are arranged in this order.

Advantages of the Invention

[0019] According to the present invention described above, a melt bag that is preferably used for packaging a hot melt adhesive, which is superior in workability during packaging such as crush resistance and ease of deformation compared to the prior art, and further superior in compatibility with the contents during use, a massive body using the same, a hot melt sheet, and a hot melt laminate can be provided.

Brief Description of the Drawings

[0020]

Figure 1

Modes for Carrying Out the Invention

[0021] Hereinafter, a melt bag, a hot melt sheet, and a hot melt laminate that are preferably used for packaging the hot melt adhesive of the present invention will be described in more detail, but the present invention is not limited thereto. A melt bag packaging a hot melt adhesive is made into a massive body. Note that the hot melt adhesive includes a hot melt pressure-sensitive adhesive. In this specification, a numerical range specified using "~" shall include the numerical values described before and after "~" as the range of the lower limit value and the upper limit value. In this specification, the hot melt adhesive may be abbreviated as "hot melt". In addition, each of the various components appearing in this specification may be used alone or in combination of two or more, unless otherwise noted. In addition, unless otherwise specified, "parts" and "%" represent "parts by mass" and "mass %", respectively.

[0022] ≪Melting Bag≫ The melting bag of the present invention is preferably used for packaging hot melt adhesives. However, this is not the case if it can technically contribute to articles other than hot melt adhesives. The melting bag can be formed (manufactured) by heating and melting a material (resin composition) containing at least a styrenic elastomer (A) by a known method.

[0023] The melt viscosity (mPa·s) of the melting bag at 160 °C is 30,000 or less. It is preferably 25,000 or less, more preferably 20,000 or less. Also , 1,000 or more is preferable, 2,000 or more is more preferable, and 3,000 or more is even more preferably preferred. Although the influence of the film thickness must be considered, when the melt viscosity is within the above range, it is easy to achieve both crush resistance and compatibility. In addition, since the melting bag and the resin composition differ in the presence or absence of film formation but are otherwise the same in this specification, the preferable properties of the melting bag can be read 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, 150 °C or lower is preferable, 130 °C or lower is more preferable, 110 °C or lower is even more preferable, and 100 °C or lower is particularly preferable. When the softening point is within the above range, crush resistance and antiblocking properties are likely to be exhibited. The measurement of the softening point is carried out in accordance with JIS K-2207 (Petroleum Asphalt) 6.4 Softening Point Test Method (Ring and Ball Method).

[0025] The film thickness of the melt bag is preferably 25 to 500 μm, more preferably 50 to 500 μm, still more preferably 50 to 300 μm, and particularly preferably 50 to 200 μm. By the film thickness being 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 melt bag is preferably 3% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, and preferably substantially free. By the amount of VOCs being within the above range, it is easy to be suitable for applications that emphasize hygiene, 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 styrenic elastomer (A). It is preferably further contained with a process oil (B) and a tackifier (C). It is preferable to contain the process oil (B) because it is excellent in compatibility and ease of deformation, and to contain the tackifier (C) because it is excellent in crush resistance.

[0028] <Styrenic Elastomer (A)> The styrenic elastomer (A) is a kind of thermoplastic elastomer. A thermoplastic elastomer refers to a material that has properties similar to those of vulcanized rubber at normal temperature and is an elastic material, and at high temperature, like ordinary thermoplastic resins, it is a polymer material that can use existing molding machines as they are. Thermoplastic elastomers have properties intermediate between rubber and plastic because they have both a rubber component (soft segment: soft phase) with elasticity and a molecular constraint component (hard segment: hard phase) for preventing plastic deformation in the molecule. Styrene-based elastomers generally have polystyrene blocks and rubber intermediate blocks. The polystyrene part forms physical cross-links (domains) to serve as cross-linking points, and the intermediate rubber blocks impart rubber elasticity to the product. The intermediate soft segments include polybutadiene (B), polyisoprene (I), and polyolefin elastomers (ethylene-propylene (EP), ethylene-butylene (EB), butylene-butadiene (BB)). Depending on the arrangement pattern with the polystyrene (S) of the hard segment, they are divided into linear (linear type) and branched (radial type).

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

[0030] The styrene-based elastomer (A) preferably has a styrene content of 10 to 50% by mass, more preferably 15 to 45% by mass, and still more preferably 20 to 40% by mass. When the styrene content is within this range, it is easier to balance the strength for expressing crush resistance and the flexibility for expressing ease of deformation. The styrene content refers to the content (% by mass) of styrene in 100% by mass of the styrene-based elastomer.

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

[0032] The content of the styrenic elastomer (A) is preferably from 1 to 70% by mass, more preferably from 3 to 60% by mass, still more preferably from 5 to 50% by mass, and particularly preferably from 10 to 45% by mass in 100% by mass of the resin composition. By containing the styrenic elastomer (A) within 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 rubbers, thermoplastic elastomers, etc. It is a process oil produced in so-called petroleum refining, etc., and is roughly classified into paraffinic process oil, aromatic process oil, and naphthenic process oil. Pro Process oil is a mixture of paraffin chains, aromatic rings, and naphthenic rings. Those with paraffin chain carbon of 50% by mass or more in total carbon are classified as paraffinic process oil, those with aromatic carbon of 30% by mass or more in total carbon are classified as aromatic process oil, and those with naphthenic ring carbon of 30% by mass or more in total carbon are classified as naphthenic process oil.

[0034] The content of process oil (B) is preferably from 5 to 90% by mass, more preferably from 10 to 80% by mass, still more preferably from 15 to 70% by mass, and particularly preferably from 20 to 60% by mass in 100% by mass of the resin composition. By containing process oil (B) within the above range, it has excellent ease of deformation.

[0035] <Tackifier (C)> The tackifier (C) is a polymer with a relatively low molecular weight of several hundred to several thousand. It exhibits liquid or solid characteristics at normal temperature. By adding the tackifier, fluidity and tack are imparted, and the adhesive strength is improved. In the present invention, it is not particularly limited as long as it is a solid at normal temperature. If it is a solid at normal temperature, it has excellent crush resistance and serves to enhance the adhesive strength, which is its original function, when used as a hot melt.

[0036] The tackifier (C) is roughly classified into natural resin-based and synthetic resin-based types. Examples of natural resin-based types include rosin-based resins and terpene-based resins, and examples of synthetic resin-based types include petroleum-based resins, phenol-based resins, and xylene-based resins. Any tackifier can be used alone or in combination according to the application.

[0037] The tackifier (C) preferably contains at least one of fully hydrogenated petroleum resins and partially hydrogenated petroleum resins. By containing at least one of fully hydrogenated petroleum resins and partially hydrogenated petroleum resins, excellent crush resistance can be achieved. Since fully hydrogenated petroleum resins and partially hydrogenated petroleum resins do not have aromatic rings that enhance intermolecular affinity, they tend to be less likely to block. At first glance, using the tackifier (C) itself in a melt bag seems to be an act contrary to the role of the melt bag, but it is preferably used from the perspective of compatibility with the encapsulated hot melt adhesive.

[0038] The content of the tackifier (C) is preferably 0 to 50% by mass, more preferably 0 to 45% by mass, and even more preferably 5 to 40% by mass in 100% by mass of the resin composition. By containing the tackifier (C) within the above range, it is easy to balance crush resistance and ease of deformation while adjusting the amount of the process oil (B). From the perspective of compatibility, the content of the tackifier (C), or the aforementioned 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 in 100% by mass of the resin composition.

[0039] Within the scope where the problems of the present invention can be solved, as components contained in the resin composition for forming the melting bag, waxes such as polyethylene wax, polypropylene wax, Fischer-Tropsch wax, paraffin wax, microcrystalline wax, α-methylstyrene resin, and other thermoplastic elastomers can be used. Examples of other thermoplastic elastomers include olefin-based, urethane-based, polyester-based, polyamide-based, 1,2-butadiene-based, and the like. Also, if necessary, antioxidants, anti-aging agents, etc. for preventing thermal degradation and thermal decomposition can be added.

[0040] [Manufacture of Resin Composition] The resin composition can be compounded and mixed in a known manner while heating the above-described materials. Although workability increases when diluted with an organic solvent or the like, it is preferable not to use an organic solvent as much as possible because it imposes restrictions on application development.

[0041] [Block] The block is obtained by packaging a hot melt adhesive with a melting bag. As the weight, 10 g to 5000 g is preferable. If it is within the above range, it is easy to handle and is preferable because of excellent workability in the number of filling operations. The film thickness of the melting bag can be appropriately adjusted according to the weight. After forming (manufacturing) the melting bag, the block can be obtained by filling the hot melt adhesive so that air does not enter as much as possible. This step is preferably carried out immediately after film formation by cooling or in water from the viewpoint of energy efficiency.

[0042] [Hot Melt Adhesive] For example, when the hot melt adhesive is for adhesive applications, it is preferable to contain a styrene-based elastomer as the resin-based material because various adhesive performances are likely to be exhibited. As the styrene-based elastomer, the same materials as those used in the resin composition for manufacturing the melting 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-based elastomer (A), the process oil (B) and the tackifier (C) can be appropriately selected depending on the application of the hot melt.

[0043] In the case of a hot melt for PET bottle labels, since releasability by an alkaline aqueous solution is required, 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% in 100 mass% of the hot melt adhesive, more preferably 1 to 60 mass%, further preferably 15 to 55 mass%, and particularly preferably 25 to 50 mass%. The higher the acid value, the lower the content can be. In addition, for environmentally friendly products, a tackifier with a high biomass degree 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. A hot melt adhesive having a softening point within the above range exhibits tackiness at room temperature, and therefore has excellent compatibility with melting bags while enjoying the advantages of being made into a mass, and also easily exhibits cohesive force when used as a hot melt.

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

[0046] <Hot melt sheet> The hot melt sheet is a sheet-shaped molded article in a lump form. It can be manufactured 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, and known methods are used. There are an open wheel method, a close gun method, a direct coat method, etc. When emphasizing re-peelability according to the application, the open wheel method and the direct coat method are preferred. The film thickness of the hot melt sheet varies depending on the application, but it is generally used with a thickness of 10 μm to 100 0 μm.

[0048] The ball tack of the hot melt sheet is not particularly limited, but in label applications such as food packaging, etc., it is preferably 4 or more at a thickness of 25 μm. It is preferable because sufficient adhesive strength can be obtained by setting it to 4 or more. The measurement method of the ball tack is described in detail in the column of the examples.

[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. Its manufacturing method is not particularly limited, but (a) applying a hot melt to the peeled surface of a peeled film to produce a hot melt sheet with a peeled film, and laminating an adherend on the surface of the hot melt layer, (i) directly applying a hot melt to the adherend, and laminating the peeled surface of the peeled film on the surface of the hot melt layer, (u) peeling the peeled film from the laminate obtained in (a) or (i) and further laminating an adherend on the surface of the hot melt layer, etc. can be obtained.

[0050] (Adherend) The adherend is not particularly limited, but plastics, non-woven fabrics, and paper can be preferably used. Examples of plastics include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, triacetyl cellulose, other plastic materials such as polysulfone, polyarylate, and polycycloolefin. Examples of non-woven fabrics include non-woven fabrics made of hydrophilic fibers such as cotton and rayon, and non-woven fabrics obtained by subjecting synthetic resin fibers to a hydrophilic treatment. Examples of paper include Yupo paper, coated paper, fine paper, cardboard, and the like. Note that the adherend can be used alone or in combination of two or more.

[0051] The uses of the hot melt laminate are not particularly limited, and examples include food labels, sanitary materials such as diapers and sanitary products, and bonding materials used for personal computers, cameras, and medical devices.

Examples

[0052] Next, examples will be shown for more detailed explanation, but the present invention is not limited thereto. In the examples, unless otherwise specified, "parts" means "parts by mass", "%" means "% by mass", and "RH" means relative humidity. Also, the compounding amounts in the table are in parts by mass. Note that the blanks in the table indicate that no compounding is performed.

[0053] [Weight average molecular weight] The measurement of the weight average molecular weight (Mw) was carried out using a GPC "LC-GPC system" manufactured by Shimadzu Corporation. The determination of the weight average molecular weight (Mw) can be performed by conversion using polystyrene with a known molecular weight as a standard substance. Apparatus name: LC-GPC system "Prominence" manufactured by Shimadzu Corporation Column: Four GMHXL columns manufactured by Tosoh Corporation and one HXL-H column manufactured by Tosoh Corporation were connected. Mobile phase solvent: Tetrahydrofuran Flow rate: 1.0 ml / min Column temperature: 40 °C

[0054] [Melt flow rate (MFR)] MFR is compliant with JIS.K7210 and uses the Melt Indexer L244 (Takara Kogyo Co., Ltd.) The sample was filled into a cylinder of 9.55 mm in inner diameter and 162 mm in length (manufactured by Co., Ltd.) and melted at 190°C. After that, a load was applied evenly using a plunger weighing 2,160 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) through 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 (Arakawa Chemical Co., Ltd., hydrogenated petroleum resin, softening point: 100°C) · Haritack F (manufactured by Harima Kasei Co., Ltd., hydrogenated rosin-based, acid value: 170 mgKOH / 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 , MFR 4 g / 10 min) · EVA: Ethylene-vinyl acetate copolymer (vinyl acetate content 28% by mass, MFR 6 g / 10 min)

[0060] (Example 1) <Production of resin composition P-1>[ Into a stainless steel beaker equipped with a stirrer, 30 parts of wax: Sasol H1 and 20 parts of PW-90 as process oil (B) were charged and heated to melt. Heating was carried out while paying attention to the content reaching 130 - 150 °C. After melting, stirring was performed to obtain a uniform melt, and then while maintaining the temperature at 130 - 150 °C and continuing stirring, 10 parts of G1642 as styrene-based elastomer (A) was added to this melt. After the addition was completed, heating and stirring were carried out at a temperature of 130 - 150 °C to completely melt G1642. Then, 40 parts of tackifier (C): P-100 was added to form a molten homogeneous mixture, which was cooled to prepare resin composition P-1. After adjusting the resin composition P-1 to 160 °C, it was measured at an appropriate rotational speed using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd., "RB80L") and 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>[ Into a stainless steel beaker equipped with a stirrer, 5 parts of wax: Sasol C80 and 40 parts of PW-90 as process oil (B) were charged and heated to melt. Heating was carried out while paying attention to the content reaching 130 - 150 °C. After melting, stirring was performed to obtain a uniform melt, and then while maintaining the temperature at 130 - 150 °C and continuing stirring, 25 parts of G1726 as styrene-based elastomer (A) was added to this melt. After the addition was completed, heating and stirring were carried out at a temperature of 130 - 150 °C to completely melt G1726. Then, 30 parts of Haritack F as tackifier (C) was added to form a molten homogeneous mixture, which was cooled to produce hot melt adhesive Q-1. <Manufacture of molten bag and mass 1> Next, resin composition P-1 was charged into a molten bag molding machine and set to form a molten bag with a film thickness of 200 μm under the condition of a temperature of 100 °C. While heating hot melt adhesive Q-1, 500 g was extruded toward the molten film, and it was molded so as to be wrapped in water and then cooled in water as it was to obtain mass 1.

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

[0063] (Examples 2 - 20, Comparative Example 1) Except for changing to the compositions and blending amounts (parts by mass) described in Table 1, hot melt adhesives (Q-2 - 6) were manufactured in the same manner as in Example 1. Except for changing to the compositions and blending amounts (parts by mass) described in Tables 2 - 4, resin compositions (P-2 - 20, P'-1) were manufactured in the same manner as in Example 1, and the melt viscosities at 160 °C were measured. Subsequently, masses and hot melt sheets of Examples 2 - 20 and Comparative Example 1 in which hot melt was filled into a molten bag in the same manner as in Example 1 were obtained. In Tables 1 to 4, the melt viscosity at 160°C was abbreviated as the 160°C viscosity, hot melt as HM, styrene-based 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 tack> The obtained hot melt sheet was prepared in a size of 25 mm in width and 250 mm in length. The release film was peeled off from the hot melt sheet and fixed to an inclined plate with an inclination angle of 30 degrees, and the heavy release film was peeled off to place the adhesive surface upward. A PET film for the runway was attached to the upper part, and a steel ball (1 / 32 to 32 / 32 inches) was rolled on a sample with a 10 cm runway and a 10 cm adhesive surface, and the number of the diameter of the ball that stopped near the center of the adhesive surface was recorded.

[0069] <Ease of deformation> The ease of deformation (ease of deformation) of the obtained mass was evaluated using a rubber hardness tester type A (Shimadzu Corporation's durometer hardness tester). The evaluation criteria are as follows. [Evaluation criteria] ◎: The measured scale is 20 points or less, excellent. 〇: The measured scale exceeds 20 points to 30 points or less, good. △: The measured scale exceeds 30 points to 40 points or less, no problem in practical use. ×: The measurement scale exceeds 40 points, which is a problem in practical use.

[0070] <Burst resistance> A release film was laid on a small cardboard box, and molten hot melt adhesive was poured onto it. After natural cooling and solidification, a block-shaped hot melt adhesive with a flat surface was produced. A molten bag (10 cm square, film thickness 200 μm) was laminated on the obtained block-shaped hot melt adhesive, and further, a molten bag (10 cm square, film thickness 200 μm) and the block-shaped hot melt adhesive were laminated in this order to produce a laminate of block-shaped hot melt adhesive / molten bag / / molten bag / block-shaped hot melt. A 10 kg weight was placed on this laminate, stored at 40 °C for 24 hours, air-cooled, and then the molten bags were peeled off by hand to evaluate the burst resistance. The evaluation criteria are as follows. [Evaluation criteria] ◎: No peeling sound or peeling strength, excellent. 〇: Some peeling sound and peeling strength, good. △: Blocking occurs, but the molten bag does not break even when peeled, and there is no problem in practical use. ×: Blocking occurs, and the molten bag breaks when peeled, which is a problem in practical use.

[0071] <Compatibility> A white molten bag containing 1% by mass of titanium oxide based on the total mass of the molten bag was produced, and a white block was produced using this. The compatibility between the white molten bag and the hot melt adhesive in the melting furnace when producing a hot melt sheet from the obtained white block was evaluated by the white unevenness of the hot melt sheet. The evaluation criteria are as follows. [Evaluation criteria] ◎: No color unevenness, excellent. 〇: Color unevenness is partially visible, good. △: Color unevenness is generally visible, but there is no remaining molten part of the molten bag, and there is no problem in practical use. ×: Color unevenness is generally visible, and the molten bag also remains, which is a problem in practical use.

[0072] From the results in Tables 2 to 4, the agglomerates of Examples 1 to 20 were excellent in workability during packing and transportation, such as crush resistance and ease of deformation. Furthermore, the melt bags were excellent in compatibility with the contents during use. On the other hand, the agglomerates of Comparative Example 1 could not satisfy all of the above characteristics.

Explanation of Signs

[0073] 1 Melt bag 2 Hot melt adhesive

Claims

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

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

3. The melt bag according to Claim 1 or 2, containing at least a styrene-ethylene / butylene-styrene block copolymer as the styrenic elastomer (A).

4. The melt bag according to Claim 1 or 2, wherein the weight average molecular weight of the styrenic elastomer (A) is 300,000 or less.

5. The melt bag according to Claim 1 or 2, which is for packaging a hot melt adhesive.

6. A mass in which a hot melt adhesive is packaged in a melt bag, and the melt bag is the melt bag according to Claim 1 or 2.

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 melt bag is within 50°C.

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

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

10. A hot melt laminate in which the hot melt sheet according to Claim 8 and an adherend are arranged in this order.

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