JP2006342329A - Hot-melt adhesive for slightly adhesive substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot-melt adhesive exhibiting good adhesive strength for a slightly adhesive substrate such as a polyolefinic resin molded product even within a wide range of a low temperature (-20°C) to a high temperature (80°C). <P>SOLUTION: The hot-melt adhesive for the slightly adhesive substrate is composed of an olefin (co)polymer (A) containing propylene as an essential monomer and having 0.1-1,000 g/10 min MFR (melt flow rate) at 230°C according to the method of JIS K7210 and a pressure-sensitive adhesion imparting resin (B). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hot melt adhesive. More specifically, the present invention relates to a hot melt adhesive particularly suitable for bonding difficult-to-adhere resin molded products such as polyolefin.

Conventionally, as hot-melt adhesives used for adhesion of difficult-to-adhere substrates such as polyolefin resin molded products, from the group consisting of ethylene-based copolymers, styrene-based block copolymers, and olefin-based (co) polymers One or more selected base polymers and tackifying resins, those containing crystalline polar group-containing compounds (for example, Patent Document 1), amorphous poly α-olefins, tackifying resins and polypropylene waxes as essential components (For example, patent document 2) etc. are known.
Japanese Patent Laid-Open No. 10-168417 JP 2004-284575 A

However, when used on difficult-to-adhere substrates such as polyolefin resin molded products, the above has poor adhesive strength at low temperatures (−20 ° C.), so low temperatures (−20 ° C.) to high temperatures (80 ° C.) There was a problem that good adhesive strength could not be secured.
An object of this invention is to provide the hot-melt-adhesive which has the adhesive force excellent from the low temperature to the high temperature with respect to hard-to-bond base materials, such as a polyolefin-type resin molded product.

The inventors of the present invention have reached the present invention as a result of intensive studies to achieve the above object.
That is, the present invention comprises an olefin (co) polymer (A) having a melt flow rate at 230 ° C. of 0.1 to 1,000 g / 10 min and having propylene as an essential monomer, and a tackifier resin (B). A hot-melt adhesive for difficult-to-adhere substrates; and an adhesive bonded with the adhesive.

The hot melt adhesive of the present invention has the following effects as compared with conventional ones.
Adhesive strength to difficult-to-adhere substrates such as polyolefin resin molded products is extremely good, and good adhesive strength can be secured from low temperature (−20 ° C.) to high temperature (80 ° C.).
Furthermore, the heat-resistant creep resistance is superior to the conventional one, and the melt viscosity is low and the processability is good.

  An olefin (co) polymer having a melt flow rate (hereinafter abbreviated as MFR) at 230 ° C. according to JIS K7210 method of the present invention of 0.1 to 1,000 g / 10 min and propylene as an essential monomer ( As A), a polyolefin obtained by copolymerization of a propylene polymer or a mixture of propylene and one or more olefins having 2 to 30 carbon atoms [polymerization method], and a high molecular weight polyolefin (polypropylene or propylene and carbon) A low molecular weight polyolefin [thermal degradation method] obtained by thermal degradation of a polyolefin obtained by copolymerizing one or a mixture of two or more olefins having a number of 2 to 30 can be used.

The olefin having 2 to 30 carbon atoms to be copolymerized with propylene is ethylene, an α-olefin having 4 to 30 carbon atoms (preferably 4 to 12, more preferably 4 to 10), and 4 to 30 carbon atoms (preferably Examples of the diene include 4 to 18, more preferably 4 to 8).
Examples of the α-olefin include 1-butene, 4-methyl-1-pentene, 1-pentene, 1-octene, 1-decene and 1-dodecene, and the diene includes butadiene, isoprene, cyclopentadiene and 1 , 11-dodecadiene and the like.
Among these, an olefin having 2 to 12 carbon atoms (ethylene, α-olefin having 4 to 12 carbon atoms, butadiene, isoprene, etc.) is more preferable, and an olefin having 2 to 10 carbon atoms (ethylene, carbon number 4) is more preferable. 10 α-olefin and butadiene), particularly preferably ethylene and butene.

The MFR at 230 ° C. according to the JIS K7210 method of (A) is usually 0.01 to 1,000, preferably 0.1 to 900. When the MFR is less than 0.01, the coating property is lowered, and when it exceeds 1,000, the heat resistance is lowered.

The number average molecular weight (Mn) by gel permeation chromatography (GPC) method using polystyrene of (A) as a standard is preferably 40,000 to 1,000,000, more preferably 45,000 to 500. , Particularly preferably 50,000 to 300,000. Adhesiveness and heat resistance become favorable by setting it as this range.
Preferred as (A) of the present invention is a polypropylene having a number average molecular weight of 40,000 to 1,000,000, and propylene and one or two kinds of olefins having 2 to 30 carbon atoms. It is polyolefin (A2) obtained by the copolymerization method of the above mixture.

  The density (JIS K7112) of (A) is preferably 0.85 to 0.92, more preferably 0.86 to 0.91, and particularly preferably 0.86 to 0.90. Adhesiveness and heat resistance become favorable by setting it as this range.

  Although it does not specifically limit as a commercial item of (A), Nippon Polypro's Wintec series (for example, Wintech WFX4T), Sumitomo Chemical Co., Ltd.'s tough selenium series (for example, tough selenium X1107), etc. can be used. .

  Examples of the tackifier resin (B) constituting the hot melt adhesive composition of the present invention include rosin / rosin derivative resins (for example, polymerized rosin and rosin ester), terpene resins [for example, α-pinene, β-pinene, limonene, etc. (Co) polymer], coumarone-indene resin, petroleum resin [e.g. (co) polymer such as C5 fraction, C9 fraction, C5 / C9 fraction, dicyclopentadiene], phenolic resin (e.g. Phenol xylene formaldehyde resin, etc.) and one or more resins selected from hydrogenated products of these resins. Of these, hydrogenated terpene resins and hydrogenated petroleum resins are preferred from the viewpoint of thermal stability, odor, and hue, and more preferred are C9 fraction and C5 / C9 fraction (both ) Hydrogenated polymerized petroleum resin.

Mn by GPC of the tackifier resin (B) is preferably 200 to 3,000, more preferably 300 to 1,000.
The ring-and-ball softening point (JIS K6863) is preferably 50 to 150 ° C, more preferably 60 to 140 ° C.
Although it does not specifically limit as a commercial item of (B), Arakawa Chemical Co., Ltd. "Arcon series" (for example, Alcon P-125), Eastman Chemical Japan Co., Ltd. "Rigalite series" (for example, Rigalite R1125), Yashara Chemical Co., Ltd. “Clearon series” (for example, Clearon P-125) manufactured by the company can be used.

The content of (A) with respect to the total weight of (A) and (B) in the hot melt adhesive of the present invention is usually 3 to 40%, preferably 5 to 35% by weight, more preferably 10 to 30% by weight. %, Particularly preferably 15 to 25% by weight. When the content of (A) is 3 to 40% by weight, the heat resistance and adhesiveness are optimized.
The content of (B) is usually 25 to 65% by weight, preferably 30 to 60% by weight, more preferably 35 to 55% by weight, particularly preferably 40 to 50% by weight. Adhesiveness becomes optimal by setting it as 25 to 65 weight%.

  Further, for the purpose of improving the balance of cohesive strength, adhesiveness and workability of the hot melt adhesive of the present invention, a hydrogenated styrene-diene copolymer having a styrene unit content of 10 to 20% by weight ( C) can be contained.

  The content of the hydrogenated product (C) is preferably 5 to 60% by weight, more preferably 7 to 55% by weight, most preferably based on the total weight of (A) and (B) in the hot melt adhesive. 10 to 50% by weight. By adjusting the content of (C) to 5 to 60% by weight, the balance of cohesive strength, adhesiveness and workability of the adhesive is improved.

Examples of the diene which is an essential constituent monomer in the hydrogenated product (C) of the styrene-diene copolymer include dienes having 4 to 18 carbon atoms such as butadiene, isoprene, pentadiene, hexadiene, cyclopentadiene and cyclohexadiene. It is done.
Of these, those having 4 to 8 carbon atoms are preferred from the viewpoint of cohesion, butadiene, isoprene and cyclopentadiene are more preferred, and butadiene and isoprene are particularly preferred.

  The content of styrene units in (C) is preferably 10 to 20% by weight, more preferably 11 to 18% by weight, and particularly preferably 12 to 16% by weight. When the content of the styrene unit is 10% by weight or more, the cohesive force of the obtained hot melt adhesive is improved, and when it is 20% by weight or less, the adhesiveness with the olefin is improved.

The hydrogenated styrene-diene copolymer (C) is obtained by hydrogenating a styrene-diene copolymer, but it is not necessary to be fully hydrogenated, even if it is only partially hydrogenated. Good.
As (C), some or all of the diene blocks of the block copolymer of styrene and butadiene, the block copolymer of styrene and isoprene, and the block copolymer of styrene and (isoprene-butadiene) are hydrogenated. It has been done. Of these, preferred are those in which part or all of the diene block of the block copolymer of styrene and isoprene is hydrogenated.
The hydrogenation rate of the diene block part is preferably 50% or more, more preferably 70% or more, and particularly preferably 90% or more. By setting the hydrogenation rate within the above range, olefin adhesion is improved.

Examples of the block copolymer include diblock, triblock, and multiblock. Among these, a triblock is preferable from the viewpoint of cohesion.
Moreover, (C) includes linear polymers and radial polymers, but is not particularly limited.

  The melt index (MI) according to ASTM D1238-G method (200 ° C., 5,000 g) of (C) is usually 0.1 to 300, preferably 0.3 to 100, particularly preferably 0.5 to 50. . By setting the melt index of (C) within the above range, a hot melt adhesive having a better balance between cohesive force and adhesion processability (melt viscosity) can be obtained.

Mn of (C) is preferably 10,000 to 500,000, more preferably 20,000 to 300,000, and particularly preferably 30,000 to 200,000. By setting Mn within the above range, a hot melt adhesive that is superior in performance such as cohesive strength and workability can be obtained.

  Examples of commercially available products of (C) include “Septon series” (for example, Septon 2002) manufactured by Kuraray Co., Ltd., “Clayton series” (for example, Clayton G1657) manufactured by Clayton Polymer, and “Tuftec series” (for example, Toughtech H1062) manufactured by Asahi Kasei Chemicals. Etc. can be used.

  Further, for the purpose of improving the heat resistance of the hot melt adhesive of the present invention, a (co) polymer (D) having an aromatic ring-containing monomer as an essential constituent monomer can be contained.

  The content of the (co) polymer (D) is preferably 1 to 20% by weight, more preferably 2 to 15% by weight, particularly preferably based on the total weight of (A) and (B) in the hot melt adhesive. Is 3 to 10% by weight. Heat resistance improves by making the content of (D) 1 to 20% by weight.

  Examples of the aromatic ring-containing monomer (d1) that is an essential constituent monomer constituting the (co) polymer (D) include, for example, styrene, α-methylstyrene, and a styrene derivative [for example, an alkyl group having 1 to 4 carbon atoms or Further alkyl styrene (vinyl toluene, ethyl styrene, t-butyl styrene, etc.), halogenated styrene (eg, chlorostyrene, bromostyrene, fluorostyrene, etc.), amino group-containing styrene (eg, N, N-diethylamino styrene, etc.), Nitrile group-containing styrene (such as cyanostyrene) and polyfunctional aromatic vinyl monomer (such as divinylbenzene)]. Among these, styrene, α-methylstyrene and vinyltoluene are preferable from the viewpoint of heat resistance, and more preferable are styrene and α-methylstyrene.

Preferred as other monomers copolymerized with (d1) are nitrile group-containing vinyl monomers ((meth) acrylonitrile, etc.), hydroxyl group-containing vinyl monomers [2-hydroxyethyl (meth) acrylate, polyoxy (degree of polymerization of 2 to 10). ) Alkylene (2 to 4 carbon atoms) mono (meth) acrylate, etc.], aliphatic unsaturated hydrocarbon (1-butene, 4-methyl-1-pentene, 1-pentene, 2-pentene, 1-octene, 1-octene, Decene, 1-dodecene, butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,4-hexadiene, 4,5-diethyl-1,3-octadiene and 3-butyl-1,3-octadiene), (anhydrous) unsaturated carbo Acid and its alkyl (1-12 carbon atoms) ester [(meth) acrylic acid, (iso) crotonic acid, cinnamic acid, (anhydrous) maleic acid, fumaric acid, (anhydrous) itaconic acid, maleic acid monomethyl ester, maleic acid Acid monobutyl ester and fumarate monooleyl ester], alkyl, cycloalkyl or aminoalkyl (meth) acrylate having an alkyl group of 1 to 24 carbon atoms [methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) ) Acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, myristyl (meth) acrylate, stearyl (meth) acrylate, oleyl (meth) acrylate, dimethylaminoethyl (meth) Acrylate, diethylaminoethyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclohexyl (meth) acrylate, etc.], unsaturated dicarboxylic acid dialkyl (carbon number 1-20) ester (diethyl maleate, dibutyl fumarate, etc.), and more Preferred are (meth) acrylonitrile, butadiene, (meth) acrylic acid and alkyl (meth) acrylate (having 12 to 18 carbon atoms).
Among the constituent monomers of (D), the weight proportion of (d1) is usually 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more based on the total weight of (D). is there.

  Specific examples of (D) include one or more resins selected from styrene resins having a Mn of 300 to 30,000 [for example, (co) polymers such as styrene, α-methylstyrene, vinyltoluene, etc.]. Is mentioned. Of these, preferred are (co) polymers of styrene and α-methylstyrene.

  Commercially available products include “Legit S-94” (styrene polymer, Mn = 4,000) manufactured by Sanyo Chemical Industries, Ltd., and “Endex 155” (α-methylstyrene copolymer, Mn = 6) manufactured by Eastman Chemical Japan. , 000) etc. can be used.

Further, for the purpose of improving the coatability of the hot melt adhesive of the present invention, Mn is 1,000 to 30,000, and an olefin (co) polymer (E) obtained by a thermal degradation method is contained. Can do.

  The content of (E) in the hot melt adhesive of the present invention is based on the total weight of (A) and (B) in the hot melt adhesive, preferably 3 to 45% by weight based on the hot melt adhesive, Preferably it is 5 to 40 weight%. By setting the content of (E) to 3 to 45%, the coatability is optimized.

  The density (JIS K7112) of (E) is preferably 0.86 to 0.92, more preferably 0.87 to 0.91, and particularly preferably 0.88 to 0.90. By setting it in this range, the cohesive force and adhesive force are improved.

  Mn of (E) is preferably 1,000 to 30,000, more preferably 1,500 to 25,000, and particularly preferably 2,000 to 20,000. By setting it in this range, the cohesive force and the coating property are improved.

  As a commercial product of (E), Sanyo Chemical Industries Co., Ltd. viscor series (for example, biscol 660P) etc. can be used.

Moreover, the hot melt adhesive of this invention can contain a plasticizer (F) and other additions (G) as needed.
Examples of the plasticizer (F) include paraffinic, naphthenic or aromatic process oils; liquid resins such as liquid polybutene, liquid polybutadiene, and liquid polyisoprene (Mn = 300 to 6000); hydrogenated products of these liquid resins Low molecular weight polyisobutylene; and mixtures of two or more thereof. Of these, paraffinic process oil, naphthenic process oil, and combinations thereof are preferable from the viewpoint of obtaining a composition having excellent thermal stability. The content ratio of the plasticizer in the hot melt adhesive of the present invention is usually 30% by weight or less, preferably 0.1 to 30% by weight, more preferably 1 to 20% by weight, based on the total weight of the hot melt adhesive. %.

  The other additive (G) that can be contained in the hot melt adhesive of the present invention includes an antioxidant {hindered phenol compound [for example, pentaerythryl-tetrakis [3- (3,5-di-t -Butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, etc.], phosphorus compounds [for example, tris (2,4-di-t- Butylphenyl) phosphite, etc.], sulfur compounds [eg pentaerythryl-tetrakis (3-laurylthiopropionate), dilauryl-3,3′-thiodipropionate, etc.]}; ultraviolet absorber {benzotriazole Compounds such as 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole, 2 (5-methyl-2-hydroxyphenyl) benzotriazole etc.] etc .; light stabilizer {hindered amine compounds [eg (bis-2,2,6,6-tetramethyl-4-piperidyl) sebacate etc.] etc.}; Adsorbents (alumina, silica gel, molecular sieve, etc.); organic or inorganic fillers; pigments; dyes;

  The amount of these additives is usually 5% by weight or less, preferably 3% by weight or less for the antioxidant, ultraviolet absorber and light stabilizer with respect to the weight of the hot melt adhesive. The amount is usually 40% by weight or less, preferably 15% by weight or less, and the pigment, dye and fragrance are usually 2% or less, preferably 1% or less.

Although it does not specifically limit as a manufacturing method of the hot-melt-adhesive of this invention, For example, (C), (D), (E), (F) (i) Each component (A) and (B), and as needed. ), (G) a method of heat-melt mixing; (ii) a method of adding the organic solvent (toluene, xylene, etc.) to the above-mentioned components and dissolving them by heating, mixing them uniformly, and then distilling off the solvent. . The method (i) is preferred.
Moreover, a heating melt kneader can be used as the mixing device. There are no particular restrictions on the shape of the heated melt kneader, but for example, a mixer having a highly compressible screw or ribbon stirrer, a kneader, a single or multi-screw extruder, a mixer, etc. Can be used.
The mixing temperature is usually 80 to 200 ° C., and it is preferably performed in an inert gas atmosphere such as nitrogen gas in order to prevent resin deterioration.

  The melt viscosity at 180 ° C. (JIS K7117) of the hot melt adhesive of the present invention thus obtained is preferably 1 to 100 Pa · s, more preferably 2 to 80 Pa · s, and particularly preferably 3 to 60 Pa. · S, most preferably 5 to 50 Pa · s. When the melt viscosity is 1 to 100 Pa · s, the workability is further improved.

  The viscosity change rate at 180 ° C. after heating for 48 hours at 180 ° C. of the hot melt adhesive of the present invention is preferably ± 30% or less, more preferably ± 20% or less, particularly preferably ± 15% or less, most preferably Preferably, it is ± 10% or less. When the viscosity change rate is ± 30 or less, the coating stability is further improved.

<Viscosity change rate evaluation method>
After putting 10 g of hot melt adhesive in a test tube and leaving it in an air atmosphere at 180 ° C. for 48 hours, the melt viscosity at 180 ° C. is measured, and the rate of change in viscosity with respect to the initial value is compared.

Viscosity change rate after heating for 48 hours at 180 ° C. (%) = [(180 ° C. melt viscosity after 48 hours 180 ° C.) − (Initial 180 ° C. melt viscosity)] × 100 / (initial 180 ° C. melt viscosity)

  The ring-and-ball softening point (JIS K6863) of the hot melt adhesive of the present invention is preferably 110 to 165 ° C, more preferably 120 to 155 ° C, particularly preferably 125 to 150 ° C, and most preferably 130 to 145 ° C. It is. When the softening point is 110 to 165 ° C., the heat resistance is further improved.

The adhesive body of the present invention is obtained by adhering difficult-to-adhere substrates to each other or another adherend using the hot melt adhesive.
Examples of the difficult-to-adhere substrate include PET, nylon and the like in addition to polyolefins such as polypropylene and polyethylene.
The hot melt adhesive of the present invention is used for paper, metal, wood, and other resins (for example, ABS resin, acrylic resin, polycarbonate, polyvinyl chloride, polyurethane, polyester, polystyrene, etc.) in addition to the difficult-to-adhere substrate. can do.
The hot melt adhesive of the present invention is suitable as a hot melt adhesive for adhering difficult-to-adhere resin molded products to each other or the above-mentioned other adherends because of its excellent adhesion to difficult-to-adhere resin molded products. Examples of adhesion include polyolefin resin molded products, polyolefin-based nonwoven fabrics, polyolefin films, or adhesion between these and other adherends.

Examples of the method for applying the hot melt adhesive of the present invention to an adherend include, but are not limited to, methods such as spiral coating, bead coating, roll coating, and coating coating. .
The melting temperature when applied to the adherend is usually 100 to 200 ° C., preferably 120 to 180 ° C., and the melt viscosity at the coating temperature is usually 1 to 100 Pa · s, preferably 2 to 50 Pa · s. is there.

EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. In the following, “parts” and the numerical values in Table 1 indicate parts by weight.

<Examples 1-5 and Comparative Examples 1-3>
The mixture blended according to the formulation shown in Table 1 is put into a stirrable stainless steel pressure reaction vessel, the inside of the vessel is purged with nitrogen, and then the temperature is raised to 160 ° C. by sealing, and melt mixing is performed with stirring for 4 hours. Thus, a hot melt adhesive of the present invention and a comparative hot melt adhesive were obtained.

<Explanation of symbols>
A-1: Polymerization method polypropylene resin “Tough Selenium X1107” (Mn 55,000, density 0.86) (manufactured by Sumitomo Chemical Co., Ltd.)
A-2: Polymerization-type polypropylene resin “Wintech WFX4” (Mn 55,000, density 0.90) (manufactured by Nippon Polypro Co., Ltd.)
B-1: Hydrogenated terpene resin “Clearon P-125” (softening point 125 ° C.) (manufactured by Yasuhara Chemical Co., Ltd.)
B-2: Hydrogenated terpene resin “Clearon P-85” (softening point 85 ° C.) (manufactured by Yasuhara Chemical Co., Ltd.)
C-1: Hydrogenated styrene-isoprene block copolymer “Septon 2002” (styrene content 30%) (manufactured by Kuraray Co., Ltd.)
D-1: Styrenic resin “Legit S-94” (softening point 95 ° C.) (manufactured by Sanyo Chemical Industries, Ltd.)
E-1: Thermal degradation method polypropylene resin “Biscol 660P” (Mn 3,000) (manufactured by Sanyo Chemical Industries, Ltd.)
G-1: Hindered phenol antioxidant “Irganox 1010” (manufactured by Ciba Specialty Chemicals)
G-2: Phosphorous antioxidant “ADK STAB 2112” (manufactured by Asahi Denka Kogyo Co., Ltd.)
H-1: Ethylene copolymer “Smitate KC-10” (manufactured by Sumitomo Chemical Co., Ltd.)
H-2: Propylene-based copolymer “REXTAC RT-2535” (manufactured by Huntsman)

<Performance evaluation>
Examples 1 to 5 and Comparative Examples 1 to 3 The adhesive strength obtained at a predetermined temperature, the heat-resistant creep property, and the workability of the obtained adhesives were evaluated as follows.
・ Substrate (dimensions): Polypropylene plate (width 25 mm x length 100 mm x thickness 3 mm)
Cotton (25mm width x 100mm length x 1mm thickness)
・ Sample creation method:
For evaluation of peel adhesion strength: A hot melt adhesive melted at 180 ° C. was applied to a polypropylene plate in a 3 mmφ bead shape (line shape) with a width of 25 mm, and a cotton cloth was bonded thereto.
For evaluation of heat-resistant creep property: A hot melt adhesive melted at 180 ° C. was applied to a cotton cloth in a 3 mmφ bead shape with a width of 25 mm, and the cotton cloth was bonded.

<Peel adhesion strength evaluation method>
One day after sample preparation, measurement was performed using an autograph manufactured by Shimadzu Corporation with a thermostatic bath. The sample was temperature-controlled at each measurement temperature (−20 ° C., 23 ° C., 80 ° C.) for 15 minutes, the 180 ° peel strength was measured at a tensile speed of 200 mm / min, and the peak strength was defined as the peel adhesive strength at each temperature. .

<Heat-resistant creep resistance evaluation method>
One day after the preparation of the sample, measurement was performed using a creep tester manufactured by Tester Sangyo Co., Ltd.
The sample was attached in the peeling direction, a 200 g load was applied vertically, the temperature of the sample was raised from 40 ° C. to 0.4 ° C./min, and the temperature at which the sample dropped was defined as the heat-resistant creep temperature.
One day after sample preparation, the sample was mounted in a circulating thermostat in the peeling direction, a load of 200 g was applied vertically, the sample temperature was maintained at a predetermined temperature, and the maximum temperature without deviation after 24 hours was defined as the heat resistant creep temperature. did. The predetermined temperature was confirmed by increasing it from 80 ° C by 5 ° C. However, in the test at 80 ° C., the deviation or dropped was set to 80 ° C. or less.

<Processability evaluation method>
The hot melt adhesive was evaluated from the flowability and stringing when discharged at 180 ° C. with a hand gun K-1 manufactured by Suntool.
○: Good flowability, almost no stringing △: Good flowability, with stringing ×: Poor flowability

Table 2 shows the evaluation results of the hot melt adhesives obtained in Examples 1 to 5 and Comparative Examples 1 to 3.
As is apparent from the results in Table 2, it can be seen that the hot melt adhesive of the present invention has a remarkably excellent balance of peel adhesive strength, heat resistant creep property and workability as compared with the comparative example.

The hot melt adhesive of the present invention can secure a good adhesive force from a low temperature (−20 ° C.) to a high temperature (80 ° C.) with respect to a difficult-to-bond substrate such as a polyolefin resin molded product, For a good balance between workability and workability. It is particularly suitable for a hot melt adhesive for polyolefin resin molded products.

Claims (9)

It consists of an olefin (co) polymer (A) having propylene as an essential monomer at a melt flow rate at 230 ° C. of 0.1 to 1,000 g / 10 min according to JIS K7210 method, and a tackifying resin (B). Hot melt adhesive for difficult-to-adhere substrates. The hot melt adhesive according to claim 1, wherein the melt viscosity at 180 ° C is 1 to 100 Pa · s, and the rate of change in melt viscosity at 180 ° C after heating at 180 ° C for 48 hours is ± 30% or less. The hot-melt adhesive according to claim 1 or 2, wherein a ring-and-ball softening point (JIS K6863) is 110 to 165 ° C. Further, the styrene-diene copolymer hydride (C) having a styrene unit content of 10 to 20% by weight is contained in an amount of 10 to 50% by weight based on the total weight of (A) + (B). The hot melt adhesive according to any one of claims 1 to 3. The hydrogenated product (C) comprises a hydrogenated product of a styrene-butadiene block copolymer, a hydrogenated product of a styrene-isoprene block copolymer, and a hydrogenated product of a styrene-butadiene-isoprene block copolymer. The hot melt adhesive according to claim 4, which is at least one selected from the group. The olefin (co) polymer (A) is an olefin (co) polymer (A2) having a number average molecular weight of 40,000 to 1,000,000 obtained by a polymerization method. Hot melt adhesive. Furthermore, the (co) polymer (D) containing an aromatic ring-containing monomer as an essential constituent monomer is contained in an amount of 1 to 20% by weight based on the total weight of (A) + (B). The hot melt adhesive according to any one of the above. The adhesive body formed by adhere | attaching difficult-to-adhere base materials or hard-to-adhere base materials, and another to-be-adhered body with the hot-melt-adhesive in any one of Claims 1-7. The adhesive body according to claim 8, wherein the hardly adhesive base material is a polyolefin resin.