Hot-melt adhesive

Abstract

To provide a hot-melt adhesive for vinyl chloride interior substrates, excelling in ease of disassembly, retention strength, coating performance, low-temperature laminability, and plasticizer resistance.SOLUTION: The present invention provides a hot-melt adhesive for vinyl chloride substrates in houses, comprising a polypropylene / polyethylene copolymer resin (A) polymerized with a metallocene catalyst and a tackifier (B), wherein the main component of the monomers constituting the copolymer resin (A) is propylene, and the softening point of the copolymer resin (A) is 85-115°C.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a hot melt adhesive for vinyl chloride substrates. [Background technology]

[0002] Conventionally, as adhesives used in adhesive products having an adhesive layer on at least a portion of the surface of a base layer, such as adhesive sheets, adhesive films, and adhesive tapes, solvent-type adhesives made of a base polymer, such as a rubber-based adhesive or an acrylic-based adhesive, have been widely used.

[0003] On the other hand, particularly in recent years, there has been a growing trend to eliminate solvents from the standpoints of complying with environmental regulations, disaster prevention, preventing adverse effects on the human body, etc., and hot melt pressure-sensitive adhesives have been proposed. Among these, olefin resin-based hot melt pressure-sensitive adhesives have attracted attention in terms of heat resistance and durability. Prior Art Document 1 discloses a hot melt pressure-sensitive adhesive composition containing an amorphous polyolefin containing 20% ​​by mass or more of a propylene component and a specific amount of a tackifier resin.

[0004] Applications of hot melt pressure-sensitive adhesives include interior pressure-sensitive adhesive sheets such as wallpaper and flooring materials. For such interior pressure-sensitive adhesive sheets, vinyl chloride substrates are often used because of their low cost and high durability. Since vinyl chloride substrates contain a large amount of plasticizer and are prone to deformation at high temperatures, hot melt pressure-sensitive adhesives for vinyl chloride substrates are required to have plasticizer resistance and low temperature sealing properties. Prior Art Document 2 discloses a hot melt pressure-sensitive adhesive composition having excellent adhesion to PVC substrates.

[0005] When the hot melt pressure-sensitive adhesive compositions described in Prior Documents 1 and 2 are used for vinyl chloride substrates, there is still room for improvement in low temperature heat sealability, holding power, coatability, plasticizer resistance, reheat peelability, etc. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-109360 [Patent Document 2] Japanese Patent Application Publication No. 8-3526 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a hot melt adhesive for vinyl chloride substrates that has excellent low-temperature heat sealability, holding power, coatability, plasticizer resistance and reheat peelability. [Means for solving the problem]

[0008] The present invention has the following aspects. [1] A hot melt adhesive for polyvinyl chloride substrates, comprising a polypropylene / polyethylene copolymer resin (A) polymerized with a metallocene catalyst and a tackifier (B), in which the main component of the monomer constituting the copolymer resin (A) is propylene, and the softening point of the copolymer resin (A) is 85 to 115°C. [2] The hot melt adhesive according to [1], wherein the copolymer resin (A) is present in an amount of 30 to 90 mass% and the tackifier (B) is present in an amount of 100 mass% in total of the copolymer resin (A) and the tackifier (B). [3] The hot melt adhesive according to [1] or [2], wherein the tackifier (B) contains a hydrogenated petroleum resin. [4] The hot melt adhesive according to any one of [1] to [3], further comprising an antioxidant (C), the content of the antioxidant (C) being more than 0 parts by mass and not more than 10 parts by mass per 100 parts by mass of the total of the copolymer resin (A) and the tackifier (B). [5] The hot melt adhesive according to any one of [1] to [4], further comprising a flame retardant (D), the content of the flame retardant (D) being more than 0 parts by mass and not more than 30 parts by mass per 100 parts by mass of the combined total of the copolymer resin (A) and the tackifier (B). Effect of the Invention

[0009] INDUSTRIAL APPLICABILITY The present invention makes it possible to provide a hot melt adhesive for vinyl chloride substrates that has excellent low-temperature heat sealability, holding power, coatability, plasticizer resistance and reheat peelability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In this specification, any numerical range specified using "to" is intended to include the numerical values ​​before and after "to" as the lower and upper limit values ​​of the range. In this specification, the polypropylene / polyethylene copolymer resin (A) polymerized with a metallocene catalyst may be abbreviated as "polypropylene / polyethylene copolymer resin (A)" or "copolymer resin (A)".

[0011] In this specification, the softening point of the copolymer resin (A) is a value measured in accordance with JIS K6863:1994 "Testing method for softening point of hot melt adhesives".

[0012] As described in the "Effects of the Invention" section, the hot melt adhesive of the present invention is excellent in all of the following performances: low-temperature heat sealability, holding power, coatability, plasticizer resistance, and reheat peelability. General hot melt adhesive products have been on the market for a long time, and although there are some that satisfy each individual performance, it is difficult to satisfy all of these performances at the same time. For example, if a soft composition is used to provide heat sealability at low temperatures, the holding power evaluated in a high-temperature environment such as 50°C will decrease. Conversely, if holding power is prioritized, low-temperature heat sealability will deteriorate. In addition, low-temperature heat sealability and reheat peelability are similar but different performances, and those that have low-temperature heat sealability do not necessarily have reheat peelability. Low-temperature heat sealability refers to the performance of having adhesive strength even at a low heat seal temperature such as 80 to 120°C, and reheat peelability refers to the performance (easy dismantling) of being able to peel the substrate from the adherend even when heated to a general temperature (approximately 120 to 180°C) that melts the hot melt adhesive and allowed to cool for 60 seconds. For example, if a soft composition is used with priority given to low-temperature heat sealability, there are cases where the film re-adheres after cooling during reheat peeling and cannot be peeled off, making it difficult to achieve both.

[0013] However, as a result of extensive research, the inventors have discovered the surprising effect of being able to satisfy all of the above-mentioned performance requirements by using a polypropylene / polyethylene copolymer resin (A) polymerized with a metallocene catalyst and having a specific structure and a specific softening point, and a tackifier (B).

[0014] <Hot melt adhesive> The hot melt adhesive of the present invention contains a polypropylene / polyethylene copolymer resin (A) and a tackifier (B). It is preferable that the hot melt adhesive further contains an antioxidant (C) and a flame retardant (D). The viscosity of the hot melt adhesive is not particularly limited, but it is preferable that the viscosity at 160° C. is 500 to 15,000 mPa·s. When the viscosity is in this range, the coating property becomes good. A viscosity of 1,000 to 10,000 mPa·s is more preferable.

[0015] <Polypropylene / polyethylene copolymer resin (A)> The polypropylene / polyethylene copolymer resin (A) contained in the hot melt adhesive of the present invention is a copolymer resin of polypropylene and polyethylene polymerized with a metallocene catalyst, the main component of the monomer constituting the copolymer resin (A) is propylene, and the softening point is 85° C. to 115° C. By having a softening point of 85 to 115° C., both low-temperature heat sealability and holding power can be achieved. A softening point of 85 to 100° C. is more preferable. It is known that resins polymerized with metallocene catalysts have a much narrower molecular weight distribution than resins polymerized with other catalysts. A narrow molecular weight distribution means that the molecular weight is uniform, and such resins have a low possibility of producing low molecular weight substances that cause a decrease in cohesive strength, resulting in good retention. Copolymer resin (A) is composed of polypropylene and polyethylene, which gives it optimal flexibility and softening point, allowing it to achieve both low-temperature heat sealability and holding power. When the amount of polypropylene constituting the copolymer resin (A) is greater than the amount of polyethylene, the density becomes low and the crystallinity decreases, so that the solidification time becomes long and reheat peeling becomes good.

[0016] The viscosity of the polypropylene / polyethylene copolymer resin (A) is not particularly limited, but is preferably 1500 to 10000 mPa·s at 170° C. When the viscosity is in this range, both coatability and holding power can be achieved. A viscosity of 2000 to 7000 mPa·s is more preferable.

[0017] The density of the polypropylene / polyethylene copolymer resin (A) is not particularly limited, but is preferably 0.85 to 0.90 g / cm. 2 A density in this range makes it possible to achieve both reheat peeling and retention. 2 is more preferred.

[0018] The copolymer resin (A) is preferably contained in an amount of 30 to 90 mass% out of a total of 100 mass% of the copolymer resin (A) and the tackifier (B). By containing the copolymer resin (A) in an amount of 30 to 90 mass%, both coatability and holding power can be achieved. A content of 40 to 80 mass% is more preferable.

[0019] Specific examples of polypropylene / polyethylene copolymer resins (A) in which the main component of the monomer constituting the copolymer resin is propylene include Ricosene PP1502 (metallocene catalyst polymerization, softening point 86°C), Ricosene PP1602 (metallocene catalyst polymerization, softening point 88°C), Ricosene PP2502 (metallocene catalyst polymerization, softening point 103°C), Ricosene PP2602 (metallocene catalyst polymerization, softening point 98°C), Ricosene PP3602 (metallocene catalyst polymerization, softening point 111°C), and the like, all of which are manufactured by Clariant. These can be used alone or in combination.

[0020] <Tackifier (B)> Examples of the tackifier (B) contained in the hot melt adhesive of the present invention include phenolic resins, modified phenolic resins, terpene resins, terpene phenolic resins, xylene phenolic resins, xylene resins, cyclopentadiene-phenolic resins, aliphatic and aromatic petroleum resins, phenol-modified petroleum resins, rosin esters, polymerized rosins, hydrogenated rosin esters and polymerized rosins, low molecular weight polystyrene resins, terpene resins, styrene resins, hydrogenated aliphatic and aromatic petroleum resins, etc., which can be used alone or in combination. Hydrogenated petroleum resins are preferred from the viewpoint of compatibility with the copolymer resin (A). The softening point of the tackifier (B) is not particularly limited, but is preferably 70 to 150° C. When the softening point is in this range, both coatability and holding power can be achieved. 75 to 140° C. is more preferable.

[0021] The tackifier (B) is preferably contained in an amount of 10 to 70% by mass out of a total of 100% by mass of the copolymer resin (A) and the tackifier (B). By containing the tackifier (B) in an amount of 10 to 70% by mass, both low-temperature heat sealing and holding power can be achieved. A content of 20 to 60% by mass is more preferable.

[0022] <Antioxidants (C)> The antioxidant (C) includes a radical scavenger and a peroxide decomposer. The radical scavengers include phenolic compounds, and the peroxide decomposers include phosphorus compounds.

[0023] Examples of phenolic compounds include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearin-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), 3,9-bis[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane, benzo[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane, and benzo[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane. azeopropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, C7-C9 side chain alkyl ester, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, and tocopherol.

[0024] Examples of phosphorus compounds include triphenyl phosphite, diphenyl isodecyl phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenyl ditridecyl) phosphite, cyclic neopentane tetrayl bis(octadecyl phosphite), tris(nonylphenyl) phosphite, tris(mononylphenyl) phosphite, tris(dinonylphenyl) phosphite, diisodecyl pentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-tert-butyl- 4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, tris(2,4-di-tert-butylphenyl)phosphite, cyclic neopentanetetraylbis(2,4-di-tert-butylphenyl)phosphite, cyclic neopentanetetraylbis(2,6-di-tert-butyl-4-methylphenyl)phosphite, and 2,2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite.

[0025] The antioxidants (C) can be used alone or in combination.

[0026] The content of the antioxidant (C) is preferably more than 0 parts by mass and not more than 10 parts by mass per 100 parts by mass of the total of the copolymer resin (A) and the tackifier (B). By being in this range, both coatability and stability can be achieved. More preferably, it is more than 0 parts by mass and not more than 5 parts by mass.

[0027] <Flame retardant (D)> Examples of the flame retardant include ammonium polyphosphate, triphenylphosphine oxide, aluminum triethylphosphinate, zinc diethyl diethylphosphinate, melamine cyanurate, melamine phosphate, melamine polyphosphate, melamine pyrophosphate, melamine ammonium polyphosphate, melamine ammonium pyrophosphate, melamine borate, triphenyl phosphate, resorcinol bis-(diphenyl phosphate), bisphenol A-bis-(diphenyl phosphate), resorcinal-bis-(2,6-dixylyl phosphate), aluminum hydroxide, aluminum hydroxide, magnesium dihydroxide, zinc oxide, molybdenum trioxide, antimony oxide, aluminum trihydroxide, zinc borate, calcium silicate, magnesium silicate, calcium sulfate, magnesium carbonate, dihydroxaphosphaphenanthrene, dihydroxaphosphaphenanthrene-hydroquinone, potassium diphenylsulfonesulfonate, polymethylphenylsiloxane, potassium butylperfluorosulfonate, and mixtures thereof. The content of the flame retardant (D) is preferably more than 0 parts by mass and not more than 30 parts by mass per 100 parts by mass of the total of the copolymer resin (A) and the tackifier (B). By being in this range, both coatability and stability can be achieved. The content of 0.5 to 20 parts by mass is more preferable.

[0028] The hot melt adhesive of the present invention may contain various resins other than the copolymer resin (A) and the tackifier (B), oils, softeners, dyes, pigments, ultraviolet absorbers, weather stabilizers, plasticizers, fillers, antistatic agents, and the like as optional components within a range in which the problem can be solved.

[0029] The method for producing the hot melt adhesive of the present invention is not particularly limited, and for example, the adhesive can be produced by putting the copolymer resin (A) and the tackifier (B) into a stainless steel beaker heated to 160° C. and melting and stirring the mixture while heating. The order of adding each component, the heating method, etc. are not particularly limited.

[0030] The hot melt adhesive of the present invention is for use with vinyl chloride substrates and is used by heating and melting. The adhesive coating method is not particularly limited, and examples thereof include a gravure coater, a roll coater, a die coater, and a slit coater. The coating thickness is preferably 10 to 100 μm from the viewpoints of coatability and adhesive strength.

[0031] The vinyl chloride base material is not particularly limited. Although the vinyl chloride base material usually contains a plasticizer, the type of plasticizer contained in the vinyl chloride base material is not particularly limited.

[0032] The plasticizers contained in the polyvinyl chloride base material include diethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, di-n-octyl phthalate, diisononyl phthalate, diisodecyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diethyl isophthalate, dibutyl isophthalate, diheptyl isophthalate, di-2-ethylhexyl isophthalate, di-n-octyl isophthalate, diisononyl isophthalate, diisodecyl isophthalate, ditridecyl isophthalate, butyl benzyl isophthalate, diethyl terephthalate, dibutyl terephthalate, diheptyl terephthalate, di-2-ethylhexyl terephthalate, di-n-octyl terephthalate phthalate ester plasticizers such as octyl, diisononyl terephthalate, diisodecyl terephthalate, ditridecyl terephthalate, and butyl benzyl terephthalate; trimellitate ester plasticizers such as tri-2-ethylhexyl trimellitate, trioctyl trimellitate, and triisodecyl trimellitate; pyromellitate ester plasticizers such as tetra-2-ethylhexyl pyromellitate; citric acid derivative plasticizers such as acetyl tributyl citrate; maleate ester plasticizers such as di-n-butyl maleate and di-2-ethylhexyl maleate; benzoate ester plasticizers; adipate ester plasticizers (e.g., di-2-ethylhexyl adipate, dioctyl adipate, diisononyl adipate, and diisodecyl adipate), and azelaic acid ester plasticizers (e.g., di-2-ethylhexyl azelaate). aliphatic dibasic acid ester plasticizers such as sebacic acid ester plasticizers (e.g., di-2-ethylhexyl sebacate); polyester plasticizers mainly containing low molecular weight polyesters synthesized from dibasic acids (e.g., sebacic acid, adipic acid, azelaic acid, and phthalic acid) and dihydric alcohols (e.g., glycols); phosphate ester plasticizers such as triethyl phosphate, tricresyl phosphate, triphenyl phosphate, tri-2-ethylhexyl phosphate, and trixylenyl phosphate; epoxy plasticizers such as epoxidized soybean oil, epoxidized linseed oil, epoxidized butyl stearate, and epoxidized linseed oil fatty acid butyl; and polyether ester plasticizers.

[0033] Vinyl chloride base materials are often used for the interior decoration of houses, such as wallpaper and flooring materials, and the hot melt adhesive of the present invention has excellent plasticizer resistance and low-temperature sealing properties, making it suitable for use as an adhesive sheet for interior decoration using a vinyl chloride base material. EXAMPLES

[0034] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0035] <Measurement of Softening Point of Copolymer Resin (A)> Measurement was performed in accordance with JIS K6863:1994 "Test method for softening point of hot melt adhesives."

[0036] <Measurement of viscosity of copolymer resin> The viscosity of the copolymer resin (A) at 170°C was measured according to JIS K 6862 (Method A). 300 g of the copolymer (A) melted in advance at 180°C in a heating bath was placed in a test vessel, and when the temperature reached 170°C while thoroughly stirring with a rod thermometer in the air, the viscosity was measured using a B-type viscometer (Tokimec Viscometer Model: BM, manufactured by Tokimec Sangyo Co., Ltd.). An appropriate rotor was used depending on the sample. In addition, since it is not possible to measure the viscosity of copolymer resins that are difficult to stir with a rod thermometer, the viscosity of copolymer resins that are difficult to stir with a rod thermometer was determined to be 20,000 mPa s or more, which is the upper limit of the viscosity that can be stirred with a rod thermometer.

[0037] The raw materials and mixtures used in the examples and comparative examples are as follows.

[0038] [Copolymer resin (A)] PP1602: Metallocene-catalyzed polypropylene / polyethylene copolymer resin (Clariant, product name: Ricothene PP1602, softening point: 88°C, viscosity at 170°C: 6000mPa·s) PP2602: Metallocene-catalyzed polypropylene / polyethylene copolymer resin (Clariant, product name: Ricothene PP2602, softening point: 98°C, viscosity at 170°C: 6300mPa·s) PP3602: Metallocene-catalyzed polypropylene / polyethylene copolymer resin (Clariant, product name: Ricothene PP3602, softening point: 111°C, viscosity at 170°C: 9300mPa·s)

[0039] [Other copolymer resins] RT2330: Ziegler-Natta catalyst polymerized polypropylene / polyethylene copolymer resin (manufactured by Rextack, product name: RT2330, softening point: 141°C, viscosity at 170°C: 5500mPa·s) RT2730: Ziegler-Natta catalyst polymerized polypropylene / polybutene-1 copolymer resin (manufactured by Rextack, product name: RT2730, softening point: 90°C, viscosity at 170°C: 5000mPa·s) PP6502: Metallocene-catalyzed polypropylene resin (Clariant, product name: Ricosene PP6502, softening point: 148°C, viscosity at 170°C: 1700mPa·s) TZ421: Metallocene-catalyzed polyethylene / polyhexene copolymer resin (manufactured by Tosoh, product name: Nipolon TZ421, softening point: 145°C, viscosity at 170°C: 20,000 mPa·s or higher) 6202: Metallocene-catalyzed polypropylene / polyethylene copolymer resin (manufactured by ExxonMobil, product name: Vistamax 6202, ethylene content 12% by mass, softening point: 130°C, viscosity at 170°C: 20,000 mPa·s or more)

[0040] [Tackifier (B)] F-75: Modified rosin resin (Harima Chemicals, product name: Haritac F-75, softening point 75°C) P-100: Hydrogenated petroleum resin (manufactured by Arakawa Chemical Industries, product name: Alcon P-100, softening point 100°C) P-140: Hydrogenated petroleum resin (manufactured by Arakawa Chemical Industries, product name: Alcon P-140, softening point 140°C)

[0041] [Antioxidants (C)] 1010: Phenolic antioxidant (manufactured by BASF Japan, product name: Irganox 1010) PEP-36: Phosphorus-based antioxidant (manufactured by ADEKA, product name: ADEKA STAB PEP-36)

[0042] [Flame retardant (D)] FP-600: Phosphate ester flame retardant (manufactured by Adeka, product name: Adeka STAB FP-600)

[0043] [oil] PW-90: Paraffin-based process oil (Idemitsu Kosan, product name: Diana Process PW-90)

[0044] [Example 1] Production of hot melt adhesive In a stainless steel beaker equipped with a stirrer, 60 parts by mass of PP1602 as a polypropylene / polyethylene copolymer resin (A) and 40 parts by mass of F-75 as a tackifier (B) were placed and heated and stirred. Heating was performed carefully so that the contents did not exceed 190°C. The mixture was stirred at 160°C for at least 1 hour to form a molten homogeneous mixture, which was then cooled to produce a hot melt adhesive.

[0045] [Example 1] Preparation of adhesive sheet The obtained hot melt adhesive was applied to a 2.0 mm thick polyvinyl chloride sheet at a coating speed of 5 m / min using a roll coater heated to 160°C to form an adhesive layer with a thickness of 50 μm. Next, a 38 μm thick release sheet (made of PET) was attached to this adhesive layer to obtain an adhesive sheet with a configuration of "polyvinyl chloride sheet / adhesive layer / release sheet".

[0046] [Examples 2 to 16, Comparative Examples 1 to 6] According to the compositions in Table 1, and in the same manner as in Example 1, hot melt adhesives and adhesive sheets of Examples 2 to 16 and Comparative Examples 1 to 6 were obtained.

[0047] The adhesive sheets thus obtained were used to evaluate coatability, low-temperature heat sealability, plasticizer resistance, holding power, and reheat peelability by the methods described below.

[0048] <Coatability> The viscosity at 160°C was measured according to JIS K 6862 (Method A). 300 g of hot melt adhesive, which had been melted in advance in a heating bath at 170°C, was placed in a test container and thoroughly stirred in the air with a rod thermometer until the temperature reached 160°C. The viscosity was measured using a B-type viscometer (Tokimec Viscometer Model: BM, manufactured by Toki Sangyo Co., Ltd.) to evaluate the coatability. An appropriate rotor was used depending on the sample. ○: "Viscosity is 1000 to 10000 mPa·s. Good." △: "Viscosity is 500 mPa·s or more but less than 1000 mPa·s, or more than 10,000 mPa·s but less than 15,000 mPa·s. Practical level." ×: "Viscosity is less than 500 mPa·s or more than 15,000 mPa·s. Not practical."

[0049] <Low temperature heat sealability> An adhesive sheet measuring 25 mm in width and 100 mm in length was prepared. The polyvinyl chloride side of the adhesive sheet was heat sealed to a stainless steel (SUS) plate at 120°C and 0.1 MPa for 10 seconds. After 24 hours, the sheet was pulled at a speed of 300 mm / min in a 90° direction using a tensile tester in a 23°C environment to measure the adhesive strength. ○: "Adhesive strength is 2N / 25mm or more. Good." △: "Adhesive strength is 1N / 25mm or more and less than 2N / 25mm. Practical level." ×: "Adhesive strength is less than 1N / 25mm. Not practical."

[0050] <Plasticizer resistance> An adhesive sheet measuring 25 mm in width and 100 mm in length was prepared. The polyvinyl chloride side of the adhesive sheet was heat sealed to a SUS plate at 140°C and 0.1 MPa for 10 seconds. After leaving it to stand in a 40°C environment for 240 hours, the adhesive sheet was removed and left to stand at 23°C for 2 hours, and then pulled in a 90° direction at a speed of 300 mm / min using a tensile tester in a 23°C environment to measure the adhesive strength. ○: "Adhesive strength is 2N / 25mm or more. Good." △: "Adhesive strength is 1N / 25mm or more and less than 2N / 25mm. Practical level." ×: "Adhesive strength is less than 1N / 25mm. Not practical."

[0051] <Holding power> An adhesive sheet measuring 25 mm in width and 100 mm in length was prepared. The polyvinyl chloride side of the adhesive sheet was heat sealed to a SUS plate at 140°C and 0.1 MPa for 10 seconds (adhesive area 25mm x 20mm). After leaving it to stand for 24 hours, it was hung in a 50°C environment and a load of 200g was applied in the shear direction to the end of the polyvinyl chloride base material. The time until the test piece fell (retention time) was measured to evaluate the retention force. ○: "The test piece did not fall off even after 8 hours. Good." △: "Retention time is between 4 and 8 hours. Practical level." ×: "Retention time is less than 4 hours. Not practical."

[0052] <Reheat peeling> An adhesive sheet measuring 25 mm in width and 100 mm in length was prepared. The polyvinyl chloride side of the adhesive sheet was heat sealed to a stainless steel plate at 140°C and 0.1 MPa for 10 seconds. After 24 hours, the polyvinyl chloride side was heat sealed again at 160°C and 0.1 MPa for 10 seconds. After leaving it for 60 seconds, it was pulled in a 90 degree direction at a speed of 300 mm / min using a tensile tester in a 23°C environment to measure the adhesive strength. ○: "Adhesive strength is less than 1N / 25mm. Good." △: "Adhesive strength is 1N / 25mm or more and less than 2N / 25mm. Practical level." ×: "Adhesive strength is 2N / 25mm or more. Not practical."

[0053] [Table 1]

Claims

1. The present invention comprises a polypropylene / polyethylene copolymer resin (A) polymerized with a metallocene catalyst and a tackifier (B), The main component of the monomer constituting the copolymer resin (A) is propylene, The softening point of the copolymer resin (A) is 85 to 115°C. Hot melt adhesive for polyvinyl chloride substrates.

2. The hot melt adhesive according to claim 1, wherein the copolymer resin (A) is 30 to 90 mass% and the tackifier (B) is 10 to 70 mass% in a total of 100 mass% of the copolymer resin (A) and the tackifier (B).

3. 2. The hot melt adhesive of claim 1, wherein the tackifier (B) contains a hydrogenated petroleum resin.

4. Further comprising an antioxidant (C), The content of the antioxidant (C) is more than 0 parts by mass and not more than 10 parts by mass per 100 parts by mass of the total of the copolymer resin (A) and the tackifier (B). The hot melt adhesive of claim 1.

5. Further comprising a flame retardant (D), The content of the flame retardant (D) is more than 0 parts by mass and not more than 30 parts by mass per 100 parts by mass of the total of the copolymer resin (A) and the tackifier (B). The hot melt adhesive according to any one of claims 1 to 4.

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