JP6328992B2 - Hot melt adhesive composition - Google Patents

Description

  The present invention relates to an adhesive composition suitable for a hot melt adhesive.

  Hot-melt adhesives have the property of solidifying and bonding by hot-melt bonding and then cooling (hot-melt adhesiveness). They are safe and solvent-free, and can be instantly bonded and fast bonded. Therefore, it is used in a wide range of fields such as paper processing, woodworking, sanitary materials, and electronics.

  In recent years, hot melt adhesives are required to have a lower temperature when heated and melted. Applying hot melt adhesive to an adherend at a high temperature and bonding it may limit the type of adherend that can be used due to the heat resistance problem of the adherend, or adversely affect productivity. This is not preferable. Specifically, it is preferable that bonding can be performed under a moderate temperature condition of about 100 to about 130 ° C.

  In addition, when a hot melt adhesive is formed into a film shape and used as a heat-sensitive adhesive film, it has an appropriate tackiness that can be temporarily fixed at room temperature (about 5 to about 35 ° C.). In some cases, it may be required to re-peel and re-attach easily for accuracy. Therefore, there is a strong demand for a hot-melt adhesive that has appropriate tackiness that can be re-peeled at room temperature and can be firmly bonded by performing a mild heat treatment after bonding.

In order to solve the above problems, studies have been made to apply an acrylic block copolymer to a hot-melt adhesive or a pressure-sensitive adhesive. For example, Patent Document 1 discusses a hot melt adhesive containing an acrylic block copolymer and an ethylene-unsaturated ester copolymer. Moreover, in patent document 2, the adhesive containing an acrylic block copolymer is examined. Moreover, as a resin composition having adhesiveness to olefin, for example, Patent Document 3 discusses a composition containing an acrylic block copolymer and an olefin polymer.
However, it has been difficult to produce a hot-melt adhesive having both proper tackiness and re-peelability at room temperature and hot-melt adhesiveness.

JP 2009-256497 A JP 2010-84068 A JP 2005-54065 A Japanese Patent Laid-Open No. 06-93060 Japanese National Patent Publication No. 05-507737 JP-A-11-335432

Macromolecular Chemistry and Physics, 2000, 201, p. 1108 to 1114

  Accordingly, an object of the present invention is to provide a hot melt adhesive composition having an appropriate tackiness that can be re-peeled at room temperature, and capable of being firmly bonded by performing a mild heat treatment after bonding, and the hot It is to provide a heat-sensitive adhesive film using a melt adhesive composition.

According to the invention, the object is
[1] (i) at least one olefin monomer selected from ethylene, propylene, and α-olefin having 4 or more carbon atoms, vinyl ester, methacrylic ester, acrylic ester, methacrylic acid and salts thereof, and An olefin copolymer (I) which is a copolymer with at least one polar monomer selected from acrylic acid and a salt thereof; and
(Ii) an acrylic block copolymer (II) having at least one polymer block (A) composed of methacrylic ester units and at least one polymer block (B) composed of acrylate units;
A hot-melt adhesive composition containing an olefin copolymer (I): acrylic block copolymer (II) in a mass ratio of 80:20 to 51:49 Melt adhesive composition,
[2] The hot melt adhesive composition according to the above [1], wherein the content of the polymer block (A) in the acrylic block copolymer (II) is 5 to 50% by mass,
[3] The acrylic block copolymer (II) is a diblock copolymer represented by the formula: (A)-(B), represented by the formula: (A)-(B)-(B ′). And a triblock copolymer represented by the formula: (A)-(B)-(A) [wherein (A) is the polymer block (A), (B ) Represents a polymer block (B), (B ′) represents a polymer block comprising an acrylate unit having a structure different from that of the polymer block (B), and − represents a bond of each polymer block. ] The hot melt adhesive composition according to the above [1] or [2], which is at least one acrylic block copolymer selected from
[4] The hot melt adhesive composition according to any one of [1] to [3], wherein the acrylic block copolymer (II) has a weight average molecular weight of 20,000 to 76,000,
[5] The acrylate unit constituting the polymer block (B)
Formula ^{_{CH 2 = CH-COOR 1 (}} 1)
(In formula (1), R ¹ represents an organic group having 1 to 5 carbon atoms)
An acrylic ester (b-1) represented by:
Formula ^{_{CH 2 = CH-COOR 2 (}} 2)
(In the formula (2), R ² represents an organic group having 6 to 12 carbon atoms)
The hot melt adhesive composition according to any one of the above [1] to [4], which is a unit consisting of at least one selected from acrylic acid ester (b-2) represented by:
[6] The mass ratio [(b-1) / (b-2)] of units consisting of the acrylic acid esters (b-1) and (b-2) constituting the polymer block (B) is 70/30. The hot melt adhesive composition according to [5], which is ˜0 / 100,
[7] The mass ratio of the olefin copolymer (I): acrylic block copolymer (II) is 64:36 to 51:49, according to any one of [1] to [6] above. Hot melt adhesive composition,
[8] The hot melt adhesive composition according to any one of the above [1] to [7], further comprising a tackifying resin,
[9] The hot melt adhesive composition according to the above [8], wherein the tackifying resin is at least one tackifying resin selected from rosin resins, aromatic petroleum resins, and terpene resins.
[10] A heat-sensitive adhesive film comprising the hot melt adhesive composition according to any one of [1] to [9],
[11] A laminate including an adhesive layer made of the hot melt adhesive composition according to any one of [1] to [9],
Is achieved by providing

  The hot melt adhesive composition of the present invention has appropriate tackiness that can be re-peeled at room temperature, and can be firmly bonded by performing a mild heat treatment after bonding. Moreover, the heat-sensitive adhesive film comprising this hot melt adhesive composition can be temporarily bonded at room temperature, and the subsequent main bonding can also be performed by a mild heat treatment. Therefore, it can be used suitably for adhesion of materials that are vulnerable to heat.

  Hereinafter, the present invention will be described in detail. In the present specification, “(meth) acrylic acid ester” is a general term for “methacrylic acid ester” and “acrylic acid ester”, and “(meth) acrylic” means “methacrylic” and “acrylic”. It is a generic name.

[Olefin copolymer (I)]
The olefin copolymer (I) used in the present invention comprises at least one olefin monomer selected from ethylene, propylene, and an α-olefin having 4 or more carbon atoms, vinyl ester, methacrylate ester, acrylate ester, It is a copolymer with methacrylic acid and a salt thereof, and at least one polar monomer selected from acrylic acid and a salt thereof.

  Examples of the α-olefin having 4 or more carbon atoms that serve as the olefin monomer include 1-butene, 1-hexene, 1-octene, and the like. Among the olefin monomers, ethylene, propylene, and 1-butene are preferable, and ethylene is more preferable.

  Examples of the vinyl ester serving as the polar monomer include vinyl acetate and vinyl propionate. As said methacrylic acid ester, the compound similar to the methacrylic acid ester used as the structural unit of the polymer block (A) which acrylic copolymer (II) mentioned later has is mentioned, for example. As said acrylate ester, the compound similar to the acrylate ester used as the structural unit of the polymer block (B) which acrylic copolymer (II) mentioned later has, for example is mentioned. Examples of salts of methacrylic acid include: salts of methacrylic acid and alkali metals such as sodium and potassium; salts of methacrylic acid and alkaline earth metals such as magnesium and calcium; methacrylic acid obtained from ammonium and amine, etc. Acid ammonium salt etc. are mentioned. Examples of the salt of acrylic acid include a salt of acrylic acid and an alkali metal such as sodium and potassium; a salt of acrylic acid and an alkaline earth metal such as magnesium and calcium; an acrylic obtained from acrylic acid and ammonium, an amine and the like. Acid ammonium salt etc. are mentioned. Among these polar monomers, vinyl esters and methacrylic acid esters are preferable, and methacrylic acid esters are more preferable.

  The olefin copolymer (I) is obtained by copolymerizing at least one of the above-mentioned olefin monomers and at least one of the above polar monomers. Among these olefin copolymers (I), ethylene-vinyl ester copolymers and ethylene-methacrylic acid ester copolymers are preferable, and ethylene-vinyl acetate copolymers and ethylene-methyl methacrylate copolymers are preferred. More preferred is an ethylene-methyl methacrylate copolymer.

  The content of the polar monomer unit contained in the olefin copolymer (I) is preferably 15 to 45% by mass, and more preferably 20 to 40% by mass. When the content of the polar monomer unit is less than the lower limit value, the adhesiveness tends to be lowered. When the content is larger than the upper limit value, the crystallinity may be lowered and the set time may be increased. .

  The melt flow rate (MFR) of the olefin copolymer (I) can be appropriately set according to the application of the hot melt adhesive, etc., but the MFR under the conditions of 190 ° C. and a load of 21.18 N is 1 to 5000 g / 10 min. It is preferably 10 to 2500 g / 10 minutes, and more preferably 10 to 1000 g / 10 minutes. When the MFR of the olefin copolymer (I) is within the above range, the viscosity is appropriate, and the workability during the production or use of the hot melt adhesive composition of the present invention tends to be improved. The MFR of the olefin copolymer is a value measured according to ISO-1133.

[Acrylic block copolymer (II)]
The acrylic block copolymer (II) used in the present invention comprises at least one polymer block (A) composed of methacrylic ester units and at least one polymer block (B) composed of acrylate units. Have

  Examples of the methacrylic acid ester that is a structural unit of the polymer block (A) include, for example, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylic acid. sec-butyl, tert-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, isobornyl methacrylate, methacrylic acid Methacrylic acid ester having no functional group such as phenyl and benzyl methacrylate; methoxyethyl methacrylate, ethoxyethyl methacrylate, diethylaminoethyl methacrylate, methacrylate Le 2-hydroxyethyl methacrylate, 2-aminoethyl methacrylate, glycidyl methacrylate, and methacrylic acid esters having a functional group such as tetrahydrofurfuryl methacrylate.

  Among these, from the viewpoint of improving the heat resistance and durability of the obtained hot melt adhesive composition, a methacrylic acid ester having no functional group is preferable, methyl methacrylate, ethyl methacrylate, tert-butyl methacrylate, More preferred are cyclohexyl methacrylate, isobornyl methacrylate, and phenyl methacrylate, the phase separation between the polymer block (A) and the polymer block (B) becomes clearer, and the cohesive strength of the hot melt adhesive composition is increased. To methyl methacrylate is more preferable. The polymer block (A) may be composed of one of these methacrylic acid esters or may be composed of two or more. The acrylic block copolymer (II) preferably has two or more polymer blocks (A) from the viewpoint of enhancing durability. In that case, these polymer blocks (A) may be the same or different.

  The weight average molecular weight (Mw) of the polymer block (A) is not particularly limited, but is preferably in the range of 1,000 to 50,000, and more preferably in the range of 4,000 to 20,000. When the weight average molecular weight (Mw) of the polymer block (A) is smaller than this range, the resulting acrylic block copolymer (II) may have insufficient cohesive strength. In addition, when the weight average molecular weight (Mw) of the polymer block (A) is larger than this range, the resulting acrylic block copolymer (II) has a high melt viscosity and produces a hot melt adhesive composition. In some cases, the productivity is poor. In addition, the weight average molecular weight (Mw) in this specification is the weight average molecular weight of standard polystyrene conversion calculated | required by the gel permeation chromatography (GPC) measurement. The proportion of the methacrylic acid ester unit contained in the polymer block (A) is preferably 60% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more in the polymer block (A).

  The glass transition temperature (Tg) of the polymer block (A) is preferably 80 to 140 ° C, more preferably 90 to 130 ° C, and further preferably 100 to 120 ° C. When the glass transition temperature is in this range, the polymer block (A) acts as a physical pseudo-crosslinking point at the normal use temperature of the adhesive, and the cohesive force of the hot melt adhesive is expressed. Excellent adhesive properties, adhesive durability, and heat resistance. The glass transition temperature is an extrapolation start temperature of a curve obtained by DSC measurement.

The acrylic ester which is a constituent unit of the polymer block (B) has a general formula CH ₂ = CH-COOR ¹ (1) (in the formula (1), R ¹ represents an organic group having 1 to 5 carbon atoms). An acrylate ester (hereinafter referred to as an acrylate ester (b-1)), a general formula CH ₂ ═CH—COOR ² (2) (in the formula (2), R ² is an organic compound having 6 to 12 carbon atoms) Acrylic acid ester (hereinafter referred to as acrylic acid ester (b-2)) represented by a group and an acrylic acid ester other than these.

Examples of the organic group having 1 to 5 carbon atoms represented by R ¹ include an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, and an amyl group (pentyl group); a methoxyethyl group, Examples thereof include an alkyl group having a functional group such as ethoxyethyl group, hydroxyethyl group and aminoethyl group and having a total carbon number of 1 to 5; glycidyl group, tetrahydrofurfuryl group and the like. Examples of the acrylic ester (b-1) include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, and acrylic. Acrylic acid ester having no functional group such as tert-butyl acid, amyl acrylate, isoamyl acrylate; methoxyethyl acrylate, ethoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-aminoethyl acrylate, acrylic acid Examples thereof include acrylic acid esters having a functional group such as glycidyl and tetrahydrofurfuryl acrylate.

Examples of the organic group having 6 to 12 carbon atoms represented by R ² include an alkyl group having 6 to 12 carbon atoms such as a hexyl group, an ethylhexyl group, an octyl group, a decyl group, an isobornyl group, a lauryl group, and a cyclohexyl group; And an alkyl group having a functional group such as an aromatic ring group having 6 to 12 carbon atoms such as a benzyl group, a diethylaminoester group, and a phenoxyethyl group, and having a total carbon number of 6 to 12. Examples of the acrylic ester (b-2) include n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, decyl acrylate, isobornyl acrylate, lauryl acrylate, and acrylic. Examples include acrylic acid esters having no functional group such as cyclohexyl acid, phenyl acrylate, and benzyl acrylate; acrylic acid esters having a functional group such as diethylaminoethyl acrylate and phenoxyethyl acrylate.

  Examples of the acrylic ester other than the acrylic ester (b-1) and the acrylic ester (b-2) include octadecyl acrylate.

  Among the acrylic ester (b-1), from the viewpoint of reducing the initial tack of the adhesive comprising the obtained hot melt adhesive composition, an acrylic ester having no functional group is preferable, and methyl acrylate, acrylic acid Ethyl and n-butyl acrylate are more preferable.

  Among acrylic ester (b-2), the point which improves the adhesive force after heat processing of the hot-melt-adhesive composition obtained, and the phase separation of a polymer block (A) and a polymer block (B) are clearer Therefore, an acrylic acid ester having no functional group is preferable from the viewpoint of expressing a high cohesive force when a hot melt adhesive composition is obtained, and 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate is preferable. Is more preferable. Moreover, 2-ethylhexyl acrylate is more preferable from the viewpoint that the obtained hot melt adhesive composition has appropriate tackiness at room temperature and exhibits stable durability in a wide temperature range.

  The above acrylic esters may be used alone or in combination of two or more. Moreover, 60 mass% or more in a polymer block (B) is preferable, as for the ratio of the acrylic ester unit contained in a polymer block (B), 80 mass% or more is more preferable, and 90 mass% or more is further more preferable.

  The acrylic acid ester unit constituting the polymer block (B) is from the acrylic acid ester (b-1) and the acrylic acid ester (b-2) in terms of expressing appropriate tackiness that can be removed again at room temperature. It is preferably at least one selected.

When the acrylate unit constituting the polymer block (B) is a unit composed of at least one selected from the acrylate ester (b-1) and the acrylate ester (b-2), the mass ratio [ (B-1) :( b-2)] is preferably 70:30 to 0: 100, more preferably 60:40 to 0: 100, and 60:40 to 10:90. Is more preferable, and it is still more preferable that it is 55: 45-30: 70. Within the above range, the compatibility between the acrylic block copolymer (II) and the olefin copolymer (I) increases, and stable hot melt adhesiveness can be expressed. In addition, the mass ratio of acrylic ester (b-1) and acrylic ester (b-2) can be determined by ¹ H-NMR measurement.

Examples of combinations of the acrylate ester (b-1) and the acrylate ester (b-2) used in the polymer block (B) include, for example, methyl acrylate / 2-ethylhexyl acrylate, methyl acrylate / acrylic acid n -Butyl / 2-ethylhexyl acrylate, ethyl acrylate / 2-ethylhexyl acrylate, n-butyl acrylate / 2-ethylhexyl acrylate, and the like. At this time, as the acrylic ester (b-1) and acrylic ester (b-2) to be used, the difference in solubility parameter between the acrylic ester (b-1) and the acrylic ester (b-2) is 0.3. More preferably, it is -2.5 (MPa) ^1/2 . Such solubility parameters are described in “POLYMER HANDBOOK Forth Edition”, pages 675-714 (Wiley Interscience, 1999) and “Polymer Engineering and Science”, 1974, pp. 14-15. It can be calculated by the method described. Further, when the acrylic block copolymer (II) contains two or more polymer blocks (B), the combination of the acrylate units constituting the polymer blocks (B) is the same. It may or may not be.

  When the polymer block (B) is a copolymer containing both an acrylate ester (b-1) unit and an acrylate ester (b-2) unit, the acrylate ester (b-1) and It may be composed of a random copolymer of acrylic ester (b-2), may be composed of a block copolymer, or may be composed of a gradient copolymer. When the acrylic block copolymer (II) contains two or more polymer blocks (B), the structures of the polymer blocks (B) may be the same or different. Further, the proportion of the total units of the acrylate esters (b-1) and (b-2) contained in the polymer block (B) is preferably 60% by mass or more, and 80% by mass in the polymer block (B). The above is more preferable, and 90% by mass or more is more preferable.

  The glass transition temperature (Tg) of the polymer block (B) is preferably -100 to 30 ° C, more preferably -80 to 10 ° C, further preferably -70 to 0 ° C, Most preferably, it is −60 to −10 ° C. When the glass transition temperature is in this range, when used as a hot melt adhesive, it can have tackiness at room temperature.

  The polymer block (A) and the polymer block (B) may contain components of each other as long as the effects of the present invention are not impaired. Moreover, you may contain another monomer as needed. Examples of such other monomers include vinyl monomers having a carboxyl group such as (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, and fumaric acid; (meth) acrylamide, (meth) acrylonitrile, Vinyl monomers having functional groups such as vinyl acetate, vinyl chloride, vinylidene chloride; aromatic vinyl monomers such as styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene; butadiene, isoprene, etc. Conjugated diene monomers; olefin monomers such as ethylene, propylene, isobutene and octene; and lactone monomers such as ε-caprolactone and valerolactone. When these monomers are used, the amount is preferably 40% by mass or less, more preferably 20% by mass or less, and still more preferably 10% by mass or less, based on the total mass of the monomers used for each polymer block. Used in.

  The acrylic block copolymer (II) used in the present invention may have other polymer blocks as necessary in addition to the polymer block (A) and the polymer block (B). . Examples of such other polymer blocks include styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, acrylonitrile, methacrylonitrile, ethylene, propylene, isobutene, butadiene, isoprene, octene, vinyl acetate, anhydrous Examples thereof include a polymer block or copolymer block composed of maleic acid, vinyl chloride, vinylidene chloride and the like; a polymer block composed of polyethylene terephthalate, polylactic acid, polyurethane, polydimethylsiloxane, and the like. The polymer block also includes a hydrogenated polymer block containing a conjugated diene compound such as butadiene or isoprene.

The acrylic block copolymer (II) has a structure different from that of the polymer block (A): “(A)”; the polymer block (B): “(B)”; When the polymer block (B) is “(B ′)”, the general formula:
[(A)-(B)] n
[(A)-(B)] n-A
(B)-[(A)-(B)] n
[(A)-(B)] n- (B ′)
[(A)-(B)] n-Z
[(B)-(A)] n-Z
(In the formula, n is an integer of 1 to 30, Z is a coupling site (a coupling site after a coupling agent reacts with a polymer terminal to form a chemical bond,-represents a bond of each polymer block) In addition, when a plurality of A and B are included in the formula, they may be polymer blocks having the same structure or may be polymer blocks having different structures. It is preferable that it is represented. Here, the “different structure” means the monomer unit constituting the polymer block, the molecular weight, the molecular weight distribution, the stereoregularity, and the ratio of each monomer unit and the form of copolymerization (random , Gradient, block) means a different structure. The value of n is preferably 1 to 15, more preferably 1 to 8, and further preferably 1 to 4. Among the above structures, [(A)-(B)] n, [(A)-(B)] n- (A), (B)-[(A)-(B)] n, [(A )-(B)] A linear block copolymer represented by n- (B ′) is preferred, and a diblock copolymer represented by (A)-(B), a formula: (A) — When the triblock copolymer represented by (B)-(B ′) and the triblock copolymer represented by the formula: (A)-(B)-(A) are used as a hot melt adhesive It is more preferable from the viewpoint of excellent adhesion durability.

  The total weight average molecular weight (Mw) of the acrylic block copolymer (II) used in the present invention is preferably 10,000 to 300,000. Among them, from the viewpoint of productivity when the hot melt adhesive composition of the present invention is formed into a film by heating and melting, such as a hot melt coating method, a T-die method, an inflation method, a calender molding method, a lamination method, The Mw is more preferably 10,000 to 150,000. Furthermore, when the hot melt adhesive composition of the present invention is used as a heat-sensitive adhesive film, the Mw is 20,000 from the viewpoint that it can be firmly bonded under a milder temperature condition. -76,000 is more preferable, and 50,000-75,000 is particularly preferable.

  The ratio (Mw / Mn) of the total weight average molecular weight (Mw) and number average molecular weight (Mn) of the acrylic block copolymer (II) used in the present invention is 1.0 to 1.5. preferable. When it is set as a hot-melt-adhesive composition, it is more preferable that it is 1.0-1.4 from the point which is excellent in adhesive durability, and it is further more preferable that it is 1.0-1.3.

  The content of the polymer block (A) in the acrylic block copolymer (II) used in the present invention is preferably 5 to 50% by mass, and when used as a hot-melt adhesive composition, From the viewpoint of achieving both tackiness and hot melt adhesiveness, the content of the polymer block (A) is preferably 10 to 50% by mass, more preferably 15 to 45% by mass, and 15 to 40% by mass. % Is more preferable, and 15 to 30% by mass is particularly preferable.

  Moreover, it is preferable that content of the polymer block (B) in the said acrylic block copolymer (II) used for this invention is 95-50 mass%, and 90-50 mass% from the same viewpoint as the above. It is more preferable that it is 85-55 mass%, it is still more preferable that it is 85-60 mass%, and it is especially preferable that it is 85-70 mass%.

  The method for producing the acrylic block copolymer (II) used in the present invention is not particularly limited as long as a polymer satisfying the conditions of the present invention is obtained, and a method according to a known method is adopted. be able to. In general, as a method of obtaining a block copolymer having a narrow molecular weight distribution, a method of living polymerizing monomers as constituent units is used. Examples of such living polymerization methods include a method of living polymerization using an organic rare earth metal complex as a polymerization initiator (see Patent Document 4), and an alkali metal or alkaline earth metal salt using an organic alkali metal compound as a polymerization initiator. A method of living anion polymerization in the presence of a mineral salt such as (see Patent Document 5), a method of living anion polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound (see Patent Document 6), An atom transfer radical polymerization method (ATRP) (see Non-Patent Document 1) and the like can be mentioned.

  Among the above production methods, the method of living anion polymerization using an organoalkali metal compound as a polymerization initiator in the presence of an organoaluminum compound makes the resulting block copolymer highly transparent, has little residual monomer and has an odor. When the composition is used as a hot melt adhesive composition, the generation of bubbles after bonding can be suppressed, which is preferable. The molecular structure of the methacrylic acid ester polymer block is also highly syndiotactic, which is preferable from the viewpoint of improving the heat resistance of the hot melt adhesive composition.

As the organoaluminum compound, for example, the following general formula (3)
AlR ³ R ⁴ R ⁵ (3)
Wherein R ³ , R ⁴ and R ⁵ are each independently an alkyl group which may have a substituent, an cycloalkyl group which may have a substituent, or an aryl which may have a substituent. A group, an aralkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent or an N, N-disubstituted amino group, or R ³ is any of the groups described above, and R ⁴ and R ⁵ together form an aryleneoxy group which may have a substituent.)
The organoaluminum compound represented by these is mentioned.

  As the organoaluminum compound represented by the general formula (3), isobutylbis (2,6-ditert-butyl-4-methylphenoxy) aluminum is used from the viewpoint of high living property of polymerization and easy handling. And isobutylbis (2,6-ditert-butylphenoxy) aluminum, isobutyl [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum and the like are preferable.

  Examples of the organic alkali metal compound include alkyllithium and alkyldilithium such as n-butyllithium, sec-butyllithium, isobutyllithium, tert-butyllithium, n-pentyllithium, and tetramethylenedilithium; phenyllithium, p -Aryllithium and aryldilithium such as tolyllithium and lithium naphthalene; aralkyllithium and aralkyldilithium such as dilithium produced by the reaction of benzyllithium, diphenylmethyllithium, diisopropenylbenzene and butyllithium; lithium such as lithium dimethylamide Amides; lithium alkoxides such as methoxylithium and ethoxylithium are listed. These may be used alone or in combination of two or more. Among these, alkyl lithium is preferable because of high polymerization initiation efficiency, among which tert-butyl lithium and sec-butyl lithium are more preferable, and sec-butyl lithium is more preferable.

  The living anionic polymerization is usually performed in the presence of a solvent inert to the polymerization reaction. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, and xylene; halogenated hydrocarbons such as chloroform, methylene chloride, and carbon tetrachloride; ethers such as tetrahydrofuran and diethyl ether.

  The acrylic block copolymer (II) has, for example, a desired polymer block (polymer block (A), polymer block (B), etc.) at a desired living polymer terminal obtained by polymerizing monomers. After repeating the process of forming a desired number of times, it can be produced by stopping the polymerization reaction. Specifically, for example, in the presence of an organoaluminum compound, a first step of polymerizing a monomer that forms the first polymer block with a polymerization initiator composed of an organic alkali metal compound, the second polymer block The polymer obtained through a plurality of polymerization steps including a second step of polymerizing the monomer to be formed and, if necessary, a third step of polymerizing the monomer to form the third polymer block. Acrylic block copolymer (II) can be produced by reacting the active terminal with alcohol or the like to stop the polymerization reaction. According to the above method, a binary block (diblock) copolymer comprising a polymer block (A) -polymer block (B); a polymer block (A) -polymer block (B) -heavy Polymer block (A), ternary block (triblock) copolymer comprising polymer block (A) -polymer block (B) -polymer block (B '); polymer block (A) -polymer A quaternary block copolymer comprising block (B) -polymer block (A) -polymer block (B) can be produced.

  As polymerization temperature, when forming a polymer block (A), 0-100 degreeC is preferable, and when forming a polymer block (B), -50-50 degreeC is preferable. When the polymerization temperature is lower than the above range, the progress of the reaction is slow, and it takes a long time to complete the reaction. On the other hand, when the polymerization temperature is higher than the above range, the deactivation of the living polymer ends increases, the molecular weight distribution becomes wide, and the desired block copolymer cannot be obtained. The polymer block (A) and the polymer block (B) can be polymerized in the range of 1 second to 20 hours, respectively.

[Hot melt adhesive composition]
In the hot melt adhesive composition of the present invention, the mass ratio of the olefin copolymer (I) and the acrylic block copolymer (II) is in the range of 80:20 to 51:49. With such a mass ratio, the olefinic copolymer (I) and the acrylic block copolymer (II) are included, so that it has moderate adhesiveness that can be re-removed at room temperature, and relaxes after bonding. It can be set as the hot-melt-adhesive composition which can be firmly adhere | attached by performing heat processing.

  The mass ratio of olefin copolymer (I): acrylic block copolymer (II) is from 64:36 to 51 because excellent properties are obtained in both removability at normal temperature and hot melt adhesion. : 49 is preferable, and the range of 61:39 to 54:46 is more preferable.

  The hot melt adhesive composition of the present invention is a polymer, tackifier resin, softener, wax, plasticizer, heat stabilizer, light stabilizer, antistatic agent, as long as the effects of the present invention are not impaired. Additives such as flame retardants, foaming agents, coloring agents, dyeing agents, refractive index adjusting agents, fillers, and curing agents may be included. These other polymers and additives may be included in one kind or in two or more kinds.

  Examples of the other polymer include acrylic resins excluding acrylic block copolymer (II) in the present specification such as polymethyl methacrylate and (meth) acrylic ester copolymer; polyethylene, polypropylene, polybutene -1, olefinic resins such as poly-4-methylpentene-1, polynorbornene, etc., selected from vinyl ester, methacrylic acid ester, acrylic acid ester, methacrylic acid, methacrylic acid and salts thereof, and acrylic acid and salts thereof Olefin resin in which at least one polar monomer is not copolymerized; polystyrene, styrene-maleic anhydride copolymer, high impact polystyrene, styrene-methyl methacrylate copolymer, AS resin, ABS resin, AES resin, AAS Resin, ACS resin, M Styrenic resins such as S resins; Polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polylactic acid; Polyamides such as nylon 6, nylon 66, and polyamide elastomer; Polycarbonate; Polyvinyl chloride; Polyvinylidene chloride; Polyvinyl alcohol; Polyacetal; Polyvinylidene fluoride; Polyurethane; Modified polyphenylene ether; Polyphenylene sulfide; Silicone rubber modified resin; Acrylic rubber; Silicone rubber; Styrenic thermoplastic elastomer such as SEPS, SEBS, SIS; IR, EPR, Examples thereof include olefinic rubbers such as EPDM. Among these, acrylic resin, AS resin, polylactic acid, and polyvinylidene fluoride are preferable from the viewpoint of compatibility with the acrylic block copolymer (II) contained in the hot melt adhesive composition, and acrylic resin. Is more preferable.

  When the hot-melt adhesive composition of the present invention contains a tackifying resin, it is preferable because adjustment of tack, adhesive force and holding force is facilitated. Examples of the tackifying resin include natural resins such as rosin resins and terpene resins; petroleum resins, hydrogenated (hereinafter sometimes referred to as “hydrogenated”) petroleum resins, styrene resins, and coumarone-indene resins. And synthetic resins such as phenol resins and xylene resins. Moreover, when it contains tackifying resin, as content, from a viewpoint of adhesive force and durability, with respect to a total of 100 mass parts of olefin type copolymer (I) and acrylic type block copolymer (II). It is preferably 1 to 500 parts by mass, more preferably 5 to 400 parts by mass, further preferably 10 to 300 parts by mass, particularly preferably 20 to 200 parts by mass, and 30 to 150 parts by mass. Most preferably, it is part by mass.

  Examples of the rosin resin include rosins such as gum rosin, tall oil rosin and wood rosin; modified rosins such as hydrogenated rosin, disproportionated rosin and polymerized rosin; rosin, glycerin ester of modified rosin, pentaerythritol ester, etc. Examples include rosin esters. Specific examples of the rosins include Pine Crystal KE-100, Pine Crystal KE-311, Pine Crystal KE-359, Pine Crystal KE-604, and Pine Crystal D-6250 (all manufactured by Arakawa Chemical Industries, Ltd.). It is done.

Examples of the terpene resin include terpene resins mainly composed of α-pinene, β-pinene, dipentene, etc., aromatic modified terpene resins, hydrogenated terpene resins, terpene phenol resins, and the like. Specific examples of the terpene resin include Tamorol 901 (Arakawa Chemical Industries, Ltd.). Examples such as the (hydrogenated) petroleum resin, for example, (hydrogenated) aliphatic (C ₅ series) petroleum resin, (hydrogenated) aromatic (C ₉ series) petroleum resin, (hydrogenated) copolymeric (C ₅ / C ₉ series) petroleum resin, (hydrogenated) dicyclopentadiene series petroleum resin, alicyclic saturated hydrocarbon resin and the like. Examples of the styrene resin include poly α-methylstyrene, α-methylstyrene / styrene copolymer, styrene monomer / aliphatic monomer copolymer, and styrene monomer / α-methyl. Examples thereof include styrene / aliphatic monomer copolymers, styrene monomer copolymers, and styrene monomer / aromatic monomer copolymers. Specific examples of the styrenic resin include FTR6000 series and FTR7000 series (manufactured by Mitsui Chemicals, Inc.).

  Among the above tackifying resins, rosin resins, terpene resins, and aromatic petroleum resins are preferable in terms of excellent compatibility. Among them, rosin resins and aromatic petroleum resins are preferable from the viewpoint of improving adhesiveness, In the case of a rosin resin, disproportionated or hydrogenated rosins purified by an operation such as distillation, recrystallization, or extraction are more preferable from the viewpoint of suppressing light deterioration, coloring, and generation of bubbles due to impurities. These may be used alone or in combination of two or more. Moreover, about the softening point of the said tackifying resin, the thing of 50-150 degreeC is preferable from the point which expresses high adhesive force.

  Examples of the plasticizer include phthalates such as dibutyl phthalate, di-n-octyl phthalate, bis-2-ethylhexyl phthalate, di-n-decyl phthalate, diisodecyl phthalate, bis-2-ethylhexyl sebacate, di Fatty acid esters such as sebacic acid esters such as n-butyl sebacate, azelaic acid esters such as bis-2-ethylhexyl azelate, adipic acid esters such as bis-2-ethylhexyl adipate and di-n-octyl adipate; Paraffins such as chlorinated paraffins; Glycols such as polypropylene glycol; Epoxy polymer plasticizers such as epoxidized soybean oil and epoxidized linseed oil; Phosphate esters such as trioctyl phosphate and triphenyl phosphate Phosphites such as triphenyl phosphite; acrylic oligomers such as n-butyl poly (meth) acrylate and 2-ethylhexyl poly (meth) acrylate; liquid polybutene; liquid polyisobutylene; liquid polyisoprene; process Oil; naphthenic oil and the like may be mentioned, and these may be used alone or in combination of two or more.

  Examples of the filler include inorganic fibers such as glass fibers and carbon fibers and organic fibers; inorganic fillers such as calcium carbonate, talc, carbon black, titanium oxide, silica, clay, barium sulfate, and magnesium carbonate. When inorganic fibers and organic fibers are contained, durability is imparted to the obtained hot melt adhesive composition. When the inorganic filler is contained, heat resistance and weather resistance are imparted to the obtained hot melt adhesive composition.

  When the hot melt adhesive composition of the present invention is used together with a curing agent, it can be suitably used as a UV curable hot melt adhesive. Examples of the curing agent include photocuring agents such as UV curing agents, thermosetting agents, and the like, and examples include benzoins, benzoin ethers, benzophenones, anthraquinones, benzyls, acetophenones, and diacetyls. . Specifically, benzoin, α-methylol benzoin, α-t-butyl benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin-n-propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, α-methylol benzoin methyl ether, α -Methoxybenzoin methyl ether, benzoin phenyl ether, benzophenone, 9,10-anthraquinone, 2-ethyl-9,10-anthraquinone, benzyl, 2,2-dimethoxy-1,2-diphenylethane-1-one (2,2 -Dimethoxy-2-phenylacetophenone), diacetyl and the like. A hardening | curing agent may be used individually by 1 type, and may be used in combination of 2 or more type. In order to enhance the effect of these curing agents, monomers such as (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamide, (meth) acrylamide derivative, vinyl ester, vinyl ether, styrene derivative; An oligomer containing a monomer as a constituent component may be further added. In addition to these monomers, a cross-linking agent composed of a bifunctional or higher functional monomer or oligomer may be added.

  The production method of the hot melt adhesive composition of the present invention is not particularly limited. For example, each component is used in a known mixing or kneading apparatus such as a kneader ruder, an extruder, a mixing roll, a Banbury mixer, and the like. It can be produced by mixing at a temperature in the range of ° C. Moreover, after dissolving each component in an organic solvent and mixing, you may manufacture by distilling off this organic solvent. The obtained composition can be heated and melted and used as a hot melt adhesive. In addition, after dissolving and mixing each component of the hot melt adhesive in an organic solvent, the adhesive is produced by distilling off the organic solvent. After application, the organic solvent is distilled off and heat-sensitive adhesion is performed, so that it can be used as a hot melt adhesive. When the hot melt adhesive composition of the present invention is used by heating and melting, the melt viscosity is preferably low from the viewpoint of processability and handleability. For example, in the case of performing hot melt processing, it is 190 ° C. The melt viscosity before and after is preferably 100,000 mPa · s or less, more preferably 30,000 mPa · s or less, and even more preferably 1,000 mPa · s or less.

  The hot melt adhesive composition of the present invention thus obtained can be subjected to heat-sensitive adhesive processing or hot melt coating processing by a mild heat treatment. Preferably, these processes can be performed at a temperature of 130 ° C. or lower.

[Thermal adhesive film and laminate]
The hot melt adhesive composition of the present invention is suitable for adhesive products in the form of a heat-sensitive adhesive film comprising the hot melt adhesive composition or a laminate comprising an adhesive layer comprising the hot melt adhesive composition. Used for.

  In order to form the above heat-sensitive adhesive film or adhesive layer, when the hot melt adhesive composition of the present invention is used by heating and melting, for example, hot melt coating method, T-die method, inflation method, calendar molding method, lamination It can be formed into a sheet-like or film-like shape using a method or the like.

  The laminate is obtained by laminating a layer (adhesive layer) made of the hot melt adhesive composition of the present invention and various substrates such as paper, cellophane, plastic material, glass, cloth, wood and metal. It is done. Examples of the plastic material include polyethylene terephthalate, triacetyl cellulose, polyvinyl alcohol, cycloolefin resin, styrene-methyl methacrylate copolymer, polypropylene, polyethylene, polyvinyl chloride, ethylene-vinyl acetate copolymer, polycarbonate, polymethacrylic acid. Examples include, but are not limited to, a base layer made of a polymer such as methyl acid, polyethylene, or polypropylene, or a mixture of two or more of these polymers. The polymer may be a copolymer obtained by copolymerizing various monomers.

  As a structure of the said laminated body, it consists of 2 layer structure of the adhesive bond layer which consists of a hot-melt-adhesive composition of this invention, and a base material layer, for example, 2 base-material layers, and the hot-melt-adhesive composition of this invention A three-layer structure (base material layer / adhesive layer / base material layer), two different adhesive layers (a) consisting of the base material layer and the hot melt adhesive composition of the present invention, and adhesion 4 layer constitution (base material layer / adhesive layer (a) / adhesive layer (b) / base material layer) of the agent layer (b) and the base material layer, the base material layer and the hot melt adhesive composition of the present invention Four-layer configuration of an adhesive layer (a) made of a product, an adhesive layer (c) made of another material, and a base material layer (base material layer / adhesive layer (a) / adhesive layer (c) / group Material layer), 3 layers of base material layer and 2 layers of adhesive layer comprising the hot melt adhesive composition of the present invention (base material layer / adhesive layer / base material layer / adhesive layer / base material) Layer) It is, but not limited thereto.

  Although it does not restrict | limit especially as thickness ratio of the said laminated body, It is preferable that it is the range of base material layer / adhesive layer = 1 / 1000-1000 / 1 from the adhesiveness of an adhesive product obtained, durability, and handleability. The range of 1/200 to 200/1 is more preferable.

  When manufacturing the laminate, after forming the adhesive layer and the base material layer, they may be bonded together by a lamination method or the like, or the adhesive layer may be directly formed on the base material layer. The layer structure may be formed at one time by coextrusion of the adhesive layer and the base material layer.

  In the laminated body of this invention, in order to improve the adhesive force of a base material layer and an adhesive bond layer, you may give surface treatments, such as a corona discharge process and a plasma discharge process, to the surface of a base material layer previously. Moreover, you may form an anchor layer in the surface of at least one of the said adhesive bond layer and a base material layer using resin etc. which have adhesiveness.

  Examples of the resin used for the anchor layer include ethylene-vinyl acetate copolymers, ionomers, block copolymers (for example, styrene triblock copolymers such as SIS and SBS, diblock copolymers, etc.), ethylene -Acrylic acid copolymer, ethylene-methacrylic acid copolymer, etc. are mentioned. The anchor layer may be a single layer or two or more layers.

  When forming the anchor layer, the method is not particularly limited. For example, a method of forming the anchor layer by applying a solution containing the resin to the base material layer, a composition containing the resin to be the anchor layer, and the like. And a method of forming an anchor layer on the surface of the base material layer by T-die or the like after heating and melting.

When forming the anchor layer, the anchor layer and the adhesive layer may be integrally laminated on the surface of the base material layer by co-extrusion of the resin to be the anchor layer and the hot melt adhesive composition of the present invention, You may laminate | stack the resin used as an anchor layer, and a hot-melt-adhesive composition one by one on the base material layer surface. Furthermore, when the base material layer is a plastic material, the plastic material to be the base material layer, the resin to be the anchor layer, and the hot melt adhesive composition may be coextruded at the same time.
In addition, in the pressure-sensitive adhesive tape or film for surface protection or masking, the hot melt adhesive composition of the present invention is applied to the anchor layer between the base material and the pressure-sensitive adhesive in order to increase the adhesion between the base material and the pressure-sensitive adhesive. Can also be used. In that case, the layer structure may be formed at a time by co-extrusion of the base material layer, the anchor layer, and the pressure-sensitive adhesive layer.

  The adhesive comprising the hot melt adhesive composition of the present invention can be used for various applications. The heat-sensitive adhesive film comprising the hot melt adhesive composition can be used alone for various applications as an adhesive or an adhesive layer, and a laminate comprising an adhesive layer comprising the hot melt adhesive composition is also available. It can be applied to various uses. For example, for surface protection, masking, shoes, binding, packaging / packaging, office, labeling, decoration / display, bookbinding, bonding, dicing tape, sealing, anticorrosion / waterproof, medical・ Adhesives for hygiene, glass scattering prevention, electrical insulation, electronic equipment holding and fixing, semiconductor manufacturing, optical display films, adhesive optical films, electromagnetic wave shields, or sealing materials for electrical and electronic parts And adhesive tapes and films. Specific examples are given below.

  Adhesives for surface protection, adhesive tapes or films can be used for various materials such as metal, plastic, rubber, and wood. Specifically, at the time of paint processing, metal plastic processing and deep drawing processing, automotive parts, optical Can be used for surface protection of members. Examples of the automobile member include a painted outer plate, a wheel, a mirror, a window, a light, and a light cover. Examples of the optical member include various image display devices such as a liquid crystal display, an organic EL display, a plasma display, and a field emission display; a polarizing film, a polarizing plate, a retardation plate, a light guide plate, a diffusion plate, an optical disc constituting film such as a DVD;・ Precise fine coated face plate for optical applications.

  Masking adhesives, tapes, films, etc. include: masking when manufacturing printed circuit boards and flexible printed circuit boards; masking when plating and soldering on electronic equipment; manufacturing of vehicles such as automobiles, vehicles and buildings These include masking when painting, printing, and civil engineering work.

  Examples of the adhesive for shoes include an adhesive used for adhesion between a shoe main body (upper) and a shoe sole (sole), a heel, an insole, a decoration portion, and the like, and adhesion between an outer sole and a midsole.

  Examples of binding applications include binding of wire harnesses, electric wires, cables, fibers, pipes, coils, windings, steel materials, ducts, plastic bags, foods, vegetables, and grooms. Packaging applications include heavy goods packaging, export packaging, cardboard box sealing, can seals, and the like. Office applications include general office work, sealing, book repair, drafting, and memos. Examples of label usage include price, product display, tag, POP, sticker, stripe, name plate, decoration, and advertisement.

  The labels include paper, processed paper (paper subjected to aluminum deposition, aluminum lamination, varnishing, resin processing, etc.), paper such as synthetic paper; cellophane, plastic material, cloth, wood and metal. The label which uses a film etc. as a base material is mentioned. Examples of the base material include high-quality paper, art paper, cast paper, thermal paper, foil paper; polyethylene terephthalate film, polyvinyl chloride film, OPP film, polylactic acid film, synthetic paper, synthetic paper thermal, and laminate film. Can be mentioned.

  Examples of the adherend of the label include plastic products such as plastic bottles and foamed plastic cases; paper and cardboard products such as cardboard boxes; glass products such as glass bottles; metal products; and other inorganic material products such as ceramics. It is done.

  Examples of decoration / display applications include danger display stickers, line tapes, wiring markings, phosphorescent tapes, and reflective sheets.

  Examples of adhesive optical film applications include polarizing films, polarizing plates, retardation films, viewing angle widening films, brightness enhancement films, antireflection films, antiglare films, color filters, light guide plates, diffusion films, prism sheets, electromagnetic wave shielding films , Near-infrared absorbing films, functional composite optical films, ITO bonding films, impact resistance-improving films, optical films having an adhesive layer formed on at least a part or all of one or both surfaces thereof Can be mentioned. Such an adhesive optical film includes a film in which an adhesive layer made of the hot melt adhesive composition of the present invention is formed on a protective film used for protecting the surface of the optical film. The adhesive optical film is suitably used for various image display devices such as liquid crystal display devices, PDPs, organic EL display devices, electronic paper, game machines, and mobile terminals.

  Examples of electrical insulation applications include protective coating or insulation of coils, interlayer insulation such as motors and transformers, and the like. Electronic device holding and fixing applications include carrier tape, packaging, CRT fixing, splicing, rib reinforcement, and the like. Examples of semiconductor manufacturing include protection of silicone wafers. Examples of bonding applications include various bonding fields, automobiles, trains, electrical equipment, printing plate fixing, construction, nameplate fixing, general household use, rough surfaces, uneven surfaces, and adhesion to curved surfaces. Sealing applications include heat insulation, vibration proofing, waterproofing, moisture proofing, soundproofing or dustproof sealing. Examples of anticorrosion / waterproofing include gas, water pipe corrosion prevention, large-diameter pipe corrosion prevention, and civil engineering building corrosion prevention.

  For medical and hygiene applications, analgesic / anti-inflammatory agents (plasters, patches), cold patches, antipruritic patches, keratin softeners, and other transdermal absorption medicines; Various tape applications such as hemostatic bond, tape for human excrement disposal equipment (artificial anal fixation tape), suture tape, antibacterial tape, fixation taping, self-adhesive bandage, oral mucosa adhesive tape, sports tape, hair removal tape Cosmetic applications such as face packs, moisturizing sheets, and exfoliating packs; bonding applications of sanitary materials such as diapers and pet sheets; cooling sheets, thermal warmers, dustproofing, waterproofing, and pest capturing.

  Examples of electronic / electrical component sealing materials include liquid crystal monitors and solar cells.

Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the following examples.
In the examples and comparative examples, the following were used as the olefin copolymer (I).
(I-1) Trade name “Evaflex EV150” (manufactured by Mitsui DuPont Polychemical Co.): ethylene-vinyl acetate copolymer (EVA), vinyl acetate content 33%. MFR 30g / 10min (190 ° C, load 21.18N)
(I-2) Trade name “Acrylift WK402” (manufactured by Sumitomo Chemical Co., Ltd.): ethylene-methyl methacrylate copolymer (EMMA), methyl methacrylate content 25%, MFR 20 g / 10 min (190 ° C., load 21.18 N) )

  The acrylic block copolymer (II) used in Examples and Comparative Examples was synthesized by the method of the following synthesis example.

<< Synthesis Example 1 >> [Synthesis of Acrylic Block Copolymer (II-1)]
(1) After attaching a three-way cock to a 2 L three-necked flask and replacing the interior with nitrogen, 870 g of toluene and 40 g of 1,2-dimethoxyethane were added while stirring at room temperature, followed by isobutylbis (2,6- 60 g of a toluene solution containing 40 mmol of di-t-butyl-4-methylphenoxy) aluminum was added, and 2.9 g of a cyclohexane solution of sec-butyllithium containing 5.0 mmol of sec-butyllithium was further added.
(2) Subsequently, 22 g of methyl methacrylate was added thereto. The reaction solution was initially colored yellow, but became colorless after stirring for 60 minutes at room temperature.
(3) Subsequently, the internal temperature of the polymerization solution was cooled to −30 ° C., 290 g of n-butyl acrylate was added dropwise over 2 hours, and the mixture was stirred at −30 ° C. for 5 minutes after the completion of the addition.
(4) After adding 4 g of methanol to stop the polymerization reaction, the resulting reaction solution was poured into 15 kg of methanol to precipitate a liquid precipitate. Thereafter, the liquid precipitate was collected and dried to obtain 311 g of an acrylic block copolymer (II-1).

<< Synthesis Example 2 >> [Synthesis of Acrylic Block Copolymer (II-2)]
(1) After attaching a three-way cock to a 2 L three-necked flask and replacing the interior with nitrogen, 870 g of toluene and 40 g of 1,2-dimethoxyethane were added while stirring at room temperature, followed by isobutylbis (2,6- 60 g of a toluene solution containing 40 mmol of di-t-butyl-4-methylphenoxy) aluminum was added, and 2.9 g of a cyclohexane solution of sec-butyllithium containing 5.0 mmol of sec-butyllithium was further added.
(2) Subsequently, 36 g of methyl methacrylate was added thereto. The reaction solution was initially colored yellow, but became colorless after stirring for 60 minutes at room temperature.
(3) Subsequently, the internal temperature of the polymerization solution was cooled to −30 ° C., 240 g of n-butyl acrylate was added dropwise over 2 hours, and the mixture was stirred at −30 ° C. for 5 minutes after the completion of the addition.
(4) Further, 36 g of methyl methacrylate was added thereto, and the mixture was stirred overnight at room temperature.
(5) After adding 4 g of methanol to stop the polymerization reaction, the obtained reaction solution was poured into 15 kg of methanol to deposit a precipitate. Then, 311 g of acrylic block copolymer (II-2) was obtained by collecting the precipitate and drying it.

<< Synthesis Example 3 >> [Synthesis of Acrylic Block Copolymer (II-3)]
(1) After attaching a three-way cock to a 2 L three-necked flask and replacing the interior with nitrogen, 870 g of toluene and 40 g of 1,2-dimethoxyethane were added while stirring at room temperature, followed by isobutylbis (2,6- 60 g of a toluene solution containing 40 mmol of di-t-butyl-4-methylphenoxy) aluminum was added, and 2.9 g of a cyclohexane solution of sec-butyllithium containing 5.0 mmol of sec-butyllithium was further added.
(2) Subsequently, 28 g of methyl methacrylate was added thereto. The reaction solution was initially colored yellow, but became colorless after stirring for 60 minutes at room temperature.
(3) Subsequently, the internal temperature of the polymerization solution was cooled to −30 ° C., 260 g of 2-ethylhexyl acrylate was added dropwise over 2 hours, and the mixture was stirred at −30 ° C. for 5 minutes after the completion of the addition.
(4) Furthermore, 28 g of methyl methacrylate was added thereto and stirred overnight at room temperature.
(5) After adding 4 g of methanol to stop the polymerization reaction, the obtained reaction solution was poured into 15 kg of methanol to deposit a precipitate. Thereafter, the precipitate was collected and dried to obtain 315 g of an acrylic block copolymer (II-3).

<< Synthesis Example 4 >> [Synthesis of Acrylic Block Copolymer (II-4)]
(1) After attaching a three-way cock to a 2 L three-necked flask and replacing the interior with nitrogen, 870 g of toluene and 40 g of 1,2-dimethoxyethane were added while stirring at room temperature, followed by isobutylbis (2,6- 60 g of a toluene solution containing 40 mmol of di-t-butyl-4-methylphenoxy) aluminum was added, and 2.9 g of a cyclohexane solution of sec-butyllithium containing 5.0 mmol of sec-butyllithium was further added.
(2) Subsequently, 32 g of methyl methacrylate was added thereto. The reaction solution was initially colored yellow, but became colorless after stirring for 60 minutes at room temperature.
(3) Subsequently, the internal temperature of the polymerization solution was cooled to −30 ° C., and a mixture of 125 g of n-butyl acrylate and 125 g of 2-ethylhexyl acrylate was added dropwise over 2 hours. Stir for minutes.
(4) Further, 32 g of methyl methacrylate was added thereto, and the mixture was stirred overnight at room temperature.
(5) After adding 4 g of methanol to stop the polymerization reaction, the obtained reaction solution was poured into 15 kg of methanol to deposit a precipitate. Thereafter, the precipitate was collected and dried to obtain 313 g of an acrylic block copolymer (II-4).

  Structure of acrylic block copolymers (II-1) to (II-4) obtained in Synthesis Examples 1 to 4, content of each polymer block, number average molecular weight (Mn), weight average molecular weight (Mw) The molecular weight distribution (Mw / Mn) is shown in Table 1. The molecular weights of the acrylic block copolymers (II-1) to (II-4) and the content of each polymer block were measured by the following methods.

(1) Measurement of number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) in an acrylic block copolymer In terms of standard polystyrene conversion by gel permeation chromatography (hereinafter abbreviated as GPC). Calculated as molecular weight.
・ Equipment: GPC equipment “HLC-8020” manufactured by Tosoh Corporation
・ Separation column: “TSKgel GMHXL”, “G4000HXL” and “G5000HXL” manufactured by Tosoh Corporation are connected in series. ・ Eluent: Tetrahydrofuran ・ Eluent flow rate: 1.0 ml / min ・ Column temperature: 40 ° C.
・ Detection method: Differential refractive index (RI)

(2) Measurement of content of each polymer block in acrylic block copolymer In the ¹ H-NMR spectrum of the acrylic block copolymer, signals near 3.6 ppm and 4.0 ppm are respectively methyl methacrylate. Ester group of unit (—O—CH ₃ ) and ester group of acrylate unit (—O—CH ₂ —CH ₂ —CH ₂ —CH ₃ derived from n-butyl acrylate unit or 2-ethylhexyl acrylate unit) -O-CH ₂ —CH (—CH ₂ —CH ₃ ) —CH ₂ —CH ₂ —CH ₂ —CH ₃ derived from the above, and the content of each polymer block was determined by the ratio of the integral values. The mass ratio of the acrylate units contained in the polymer block (B) in Synthesis Example 4 was also determined in the same manner.
・ Apparatus: JEOL nuclear magnetic resonance apparatus “JNM-ECX400”
・ Solvent: Deuterated chloroform

In the examples and comparative examples, the following were used as the tackifier resin and the wax.
Tackifying resin: trade name “FTR-6100”, manufactured by Mitsui Chemicals, aromatic petroleum resin, softening point 95 ° C.
Wax: trade name “Sazol Wax H1,” manufactured by Sazol, synthetic wax.

<< Examples 1-9, Comparative Examples 1-2 >>
The olefin copolymer (I), the acrylic block copolymer (II) obtained in Synthesis Examples 1 to 4, the tackifier resin, and the wax are melt-mixed at a blending composition ratio shown in Table 2 (temperature 180). And a hot melt adhesive was obtained.
Next, using a hot melt coating machine manufactured by Suntool, the obtained hot melt adhesive was hot melt coated (temperature 180 ° C.) on a release treatment film (Purex A43 manufactured by Teijin DuPont Films). The release treatment film was peeled off to obtain a heat-sensitive adhesive film (thickness 50 μm). About the obtained heat-sensitive adhesive film, various physical properties were evaluated by the following methods. The results are shown in Table 2.

[Evaluation method of room temperature adhesiveness]
(1) A heat-sensitive adhesive film prepared by the above method and two polyethylene terephthalate (PET) films (Toyobo's ester film E5000, thickness 100 μm) are arranged in the order of PET film / heat-sensitive adhesive film / PET film. A laminate was prepared by bonding at 23 ° C. using a rubber roller.
(2) The laminate obtained in (1) is cut into a shape having a width of 25 mm, left at 23 ° C. and 50% RH for 1 hour, and then peeled off using a tensile tester (Instron model 5566). An adhesion strength test (based on JIS K6854-3, peeling speed of 10 mm / min) was performed.
(3) The determination of the result is “X” for an adhesive strength of less than 0.01 kN / m, “Δ” for an adhesive strength of 0.01 kN / m or more and less than 0.05 kN / m, 0.05 kN / m. Those having an adhesive strength of m or more and less than 0.1 kN / m were designated as “◯”, and those having an adhesive strength of 0.1 kN / m or more were designated as “◎”.

[Method for evaluating heat-sensitive adhesiveness]
(1) A heat-sensitive adhesive film prepared by the above method and two polyethylene terephthalate (PET) films (Toyobo's ester film E5000, thickness 100 μm) are arranged in the order of PET film / heat-sensitive adhesive film / PET film. Laminate at 23 ° C using a rubber roller, then heat laminate using a thermal laminator (VAII-700 type) manufactured by Taisei Laminator Co., Ltd. under the conditions of a laminating roll temperature of 120 ° C and a laminating speed of 1 m / min. A laminate was prepared.
(2) The laminate obtained in (1) is cut into a shape having a width of 25 mm, left at 23 ° C. and 50% RH for 1 hour, and then peeled off using a tensile tester (Instron model 5566). An adhesion strength test (based on JIS K6854-3, peeling speed of 10 mm / min) was performed.
(3) Judgment of the result is “X” for an adhesive strength of less than 0.1 kN / m, “Δ” for an adhesive strength of 0.1 kN / m or more and less than 0.5 kN / m, 0.5 kN / m Those having an adhesive strength of m or more and less than 1 kN / m were designated as “◯” and those having an adhesive strength of 1 kN / m or more as “「 ”.

[Method for evaluating adhesion durability]
(1) A heat-sensitive adhesive film prepared by the above method and two polyethylene terephthalate (PET) films (Toyobo's ester film E5000, thickness 100 μm) are arranged in the order of PET film / heat-sensitive adhesive film / PET film. Laminate at 23 ° C using a rubber roller, then heat laminate using a thermal laminator (VAII-700 type) manufactured by Taisei Laminator Co., Ltd. under the conditions of a laminating roll temperature of 120 ° C and a laminating speed of 1 m / min. A laminate was prepared.
(2) The laminate obtained in (1) was stored under the conditions of 80 ° C., 85% RH and 1000 hours, and then allowed to stand at 23 ° C. × 50% RH for 24 hours to obtain a tensile tester (5566 manufactured by Instron). T-type peel adhesion strength test (based on JIS K6854-3, peel speed of 10 mm / min) was performed using a mold.
(3) Judgment of the result is “X” for an adhesive strength of less than 0.1 kN / m, “Δ” for an adhesive strength of 0.1 kN / m or more and less than 0.5 kN / m, 0.5 kN / m Those having an adhesive strength of m or more and less than 1 kN / m were designated as “◯” and those having an adhesive strength of 1 kN / m or more as “「 ”.

  From the results of Table 2, in Examples 1 to 9, the hot melt adhesive composition of the present invention has moderate tackiness at 23 ° C. and adheres firmly only by heat laminating under a mild condition of 120 ° C. It can be seen that the adhesive durability is also excellent. On the other hand, as shown in Comparative Example 1, when the content of the acrylic block copolymer used in the present invention was less than the range of the present invention, the tackiness was insufficient at 23 ° C. Further, as shown in Comparative Example 2, when the content of the acrylic block copolymer used in the present invention is larger than the range of the present invention, the heat-sensitive adhesiveness and the adhesion durability are insufficient.

  The hot melt adhesive composition of the present invention has appropriate tackiness that can be re-peeled at room temperature, and can be firmly bonded by performing a mild heat treatment after bonding. Moreover, the heat-sensitive adhesive film comprising this hot melt adhesive composition can be temporarily bonded at room temperature, and the subsequent main bonding can also be performed by a mild heat treatment. Therefore, it can be used suitably for adhesion of materials that are vulnerable to heat.

Claims (9)

(I) at least one olefinic monomer selected from ethylene, propylene, and an α-olefin having 4 or more carbon atoms, vinyl ester, methacrylic acid ester, acrylic acid ester, methacrylic acid and salts thereof, and acrylic acid and An olefin copolymer (I) which is a copolymer with at least one polar monomer selected from the salts; and
(Ii) an acrylic block copolymer (II) having at least one polymer block (A) composed of methacrylic ester units and at least one polymer block (B) composed of acrylate units;
A hot-melt adhesive composition containing an olefin copolymer (I): acrylic block copolymer (II) in a mass ratio of 80:20 to 51:49 A melt adhesive composition ,
Acrylic acid ester units constituting the polymer block (B)
Formula _{^{CH 2 = CH-COOR 1 (}} 1)
(In formula (1), R ¹ represents an organic group having 1 to 5 carbon atoms)
An acrylic ester (b-1) represented by:
Formula _{^{CH 2 = CH-COOR 2 (}} 2)
(In the formula (2), R ² represents an organic group having 6 to 12 carbon atoms)
It is a unit consisting of at least one selected from the acrylate ester (b-2) represented by formula (b-2) and the acrylate esters (b-1) and (b-2) constituting the polymer block (B). A hot melt adhesive composition having a unit mass ratio [(b-1) :( b-2)] of 70:30 to 0: 100 .   The hot melt adhesive composition according to claim 1, wherein the content of the polymer block (A) in the acrylic block copolymer (II) is 5 to 50 mass%.   The acrylic block copolymer (II) is a diblock copolymer represented by the formula: (A)-(B), a triblock represented by the formula: (A)-(B)-(B ′). A block copolymer, and a triblock copolymer represented by the formula: (A)-(B)-(A) [wherein (A) represents a polymer block (A) and (B) represents a heavy polymer) The combined blocks (B) and (B ′) represent polymer blocks composed of acrylate units having a structure different from that of the polymer block (B), and − represents a bond of each polymer block. The hot-melt adhesive composition according to claim 1 or 2, which is at least one acrylic block copolymer selected from the group consisting of:   The hot melt adhesive composition according to any one of claims 1 to 3, wherein the acrylic block copolymer (II) has a weight average molecular weight of 20,000 to 76,000. The hot melt adhesive according to any one of claims 1 to 4 , wherein the mass ratio of the olefin copolymer (I): acrylic block copolymer (II) is 64:36 to 51:49. Composition. Furthermore, the hot-melt-adhesive composition of any one of Claims 1-5 containing tackifying resin. The hot-melt adhesive composition according to claim 6 , wherein the tackifying resin is at least one tackifying resin selected from rosin resins, aromatic petroleum resins, and terpene resins. The heat-sensitive adhesive film which consists of a hot-melt-adhesive composition of any one of Claims 1-7 . The laminated body containing the adhesive bond layer which consists of a hot-melt-adhesive composition of any one of Claims 1-7 .