JPH09165565A - Adhesive composition - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To provide a hot melt adhesive having excellent solvent resistance and oil resistance, and also excellent in other properties such as adhesiveness (adhesiveness), holding power, low temperature characteristics and flexibility. To provide an adhesive composition that can be effectively used as a hot-melt pressure-sensitive adhesive. SOLUTION: In forming an adhesive composition by adding a tackifying resin and optionally a wax or a softening agent or a wax to a base polymer, one or more hydrogenated butadiene polymer blocks A are used as a base polymer, A block copolymer having one or more aromatic vinyl compound polymer block B and one or more polymer block C substantially having an olefin polymer structure, wherein the vinyl bond content of block A is 20% or less. A block copolymer having a glass transition temperature of block C of −20 ° C. or lower and a heat of crystal fusion of 8 cal / g or lower and a content of block A of 3 to 50% by weight is used.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an adhesive composition. More particularly, the present invention relates to hot melt adhesives and adhesive compositions that can be effectively used as hot melt pressure sensitive adhesives. The adhesive composition of the present invention is excellent in various properties such as solvent resistance, processing stability, adhesiveness, creep resistance and low temperature flexibility, and by utilizing these properties, packaging, bookbinding, plywood production. , Woodworking, shoemaking, bonding of textile products,
It can be effectively used for a wide range of applications such as production of various adhesive products such as various adhesive tapes and labels.

[0002]

2. Description of the Related Art Conventionally, solvent-based adhesives which have been used for various purposes have been widely used. However, the use of solvents causes air pollution, danger of fire, deterioration of working environment and hygiene. There are problems such as. Therefore, in recent years, a solventless adhesive has been widely used as an alternative to the solvent adhesive. Representative examples of the solventless adhesive include an aqueous adhesive in the form of an aqueous solution or an aqueous dispersion and a hot melt adhesive used by heating and melting,
Among them, the hot melt adhesive does not require water, does not require a drying time or a drying device, and can complete the bonding in a short time after the application of the adhesive, which saves energy, workability, and productivity. It is widely used because of its superiority.

As a kind of adhesive, a pressure-sensitive adhesive is known, which is made to adhere (adhere) by utilizing its adhesiveness, and is also called an adhesive. Adhesive products provided with such a pressure-sensitive adhesive layer on a substrate such as paper, cloth, plastic tape, film, sheet, etc. are widely used in various applications as adhesive tapes, adhesive films, adhesive sheets, etc. ing. Then, in the production of pressure-sensitive adhesive products such as pressure-sensitive adhesive tapes and pressure-sensitive adhesive sheets having a pressure-sensitive adhesive layer, a solution of the pressure-sensitive adhesive in a solvent is applied to the substrate, and then the solvent is removed to remove the pressure-sensitive adhesive. A method of forming a layer on a substrate has been generally used, but in this case as well, there are problems such as air pollution associated with the use of a solvent, a risk of fire, and deterioration of working environment and hygiene. So safety,
The need for solvent-free pressure-sensitive adhesives has been recognized from the viewpoint of workability and energy saving, and it is a hot-melt type adhesive that can be heated and melted and applied to a substrate without using a solvent. Pressure sensitive adhesives are being developed.

Both hot-melt adhesives and hot-melt pressure-sensitive adhesives use a thermoplastic polymer that melts (hot-melts) when heated as a base polymer. Is ethylene / vinyl acetate copolymer, ethylene / α-
Block copolymers composed of vinyl aromatic monomer polymer blocks and conjugated diene polymer blocks such as olefin copolymers, polyamides, polyesters, styrene-butadiene-styrene block copolymers and styrene-isoprene-styrene block copolymers. Is used as the base polymer of the hot melt type pressure-sensitive adhesive, and is a block copolymer composed of an ethylene / vinyl acetate copolymer, a polymer block composed of a vinyl aromatic monomer and a conjugated diene polymer block. , Acrylic acid ester-based polymers, polyamide, polyethylene and the like are used.

Among the above-mentioned base polymers, ethylene / vinyl acetate copolymer has good adhesiveness to various base materials such as toughness, paper, wood, plastics and metals,
Hot-melt adhesives and hot-melt pressure-sensitive adhesives from the viewpoints of good compatibility with other components (tackifiers, waxes, softeners, etc.) and excellent heat fluidity and thermal stability. Widely used as a base polymer in drugs. However, since the ethylene / vinyl acetate copolymer has insufficient flexibility at low temperatures, it is possible to use an ethylene / vinyl acetate copolymer as the base polymer for hot-melt adhesives and to bond objects or hot-melt adhesives. There is a problem that various adhesive products using the pressure sensitive adhesive are not suitable for use at low temperatures.

In addition, since polyamide and polyester have lower compatibility with other components such as a tackifier than ethylene / vinyl acetate copolymer, the degree of freedom of blending is low,
Moreover, it is inferior to the ethylene / vinyl acetate copolymer in terms of handleability and adhesion to various substrates.

On the other hand, a non-hydrogenated block copolymer composed of a vinyl aromatic monomer polymer block and a conjugated diene polymer block (unhydrogenated block copolymer) is compared in adhesiveness and tackiness at room temperature. From the good thing,
Widely used as a base polymer for hot-melt adhesives and hot-melt pressure-sensitive adhesives, such unhydrogenated block copolymers have poor solvent resistance and oil resistance, and are Since it has a derived unsaturated bond in the molecule, its heat deterioration resistance and weather resistance are remarkably inferior. Further, a hydrogenated block copolymer of a polymer block of a vinyl aromatic monomer and a conjugated diene polymer block is also used as a base polymer of a hot melt adhesive and a hot melt type pressure-sensitive adhesive,
Although such a hydrogenated block copolymer is improved in weather resistance and heat deterioration resistance, it is still inferior in solvent resistance and oil resistance, and is restricted in use.

[0008]

The object of the present invention is to provide various hot-melt type adhesive compositions (hot-melt adhesives and hot-melt adhesives) which have excellent solvent resistance and oil resistance, and have good flexibility at low temperatures. Hot-melt adhesives and hot-melts that have good compatibility with various components used in hot-melt pressure-sensitive adhesives, etc., have a high degree of freedom in compounding, and exhibit excellent adhesive strength, adhesive strength, and holding power. An object is to provide an adhesive composition suitable as a pressure-sensitive adhesive (adhesive) of a mold.

[0009]

As a result of repeated studies by the present inventors in order to achieve the above object, as a result, a specific hydrogenated butadiene polymer block and a specific olefin polymer are formed together with a polymer block composed of an aromatic vinyl compound. The block copolymer having a polymer block has a solvent resistance higher than that of a hydrogenated or non-hydrogenated block copolymer composed of a conventional polymer block of a vinyl aromatic monomer and a conjugated diene polymer block. Excellent in oil resistance and oil resistance, and also extremely good in compatibility with tackifying resins and other components used in hot melt adhesives and hot melt pressure-sensitive adhesives, and Specific hydrogenated butadiene polymer blocks and specific olefin polymer blocks along with polymer blocks composed of aromatic vinyl compounds. The composition obtained by blending a block copolymer having a base polymer with a tackifying resin has good flexibility at low temperatures, and is extremely useful as a hot-melt adhesive or a hot-melt pressure-sensitive adhesive. The inventors have found that they are suitable and completed the present invention.

That is, the present invention is a block copolymer.
An adhesive composition containing (a) and a tackifying resin (b), wherein (i) the block copolymer (a) contains at least one polymer block A composed of a hydrogenated butadiene polymer, and an aroma. At least one polymer block B composed of a vinyl group compound and at least one polymer block C composed of a polymer having a substantially olefin polymer structure different from the polymer block A; (Ii) the polymer block A in the block copolymer (a) is obtained by hydrogenating a butadiene polymer block having a vinyl bond content of 20% or less; (iii) in the block copolymer (a) The glass transition temperature of the polymer block C is −20 ° C. or lower and the heat of crystal fusion is 8 cal / g or lower; and (iv) in the block copolymer (a), the polymer block before hydrogenation treatment is used. Content of 3 to 50% by weight based on the total weight of the block copolymer (a) before hydrogenation treatment.
The adhesive composition is characterized by:

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. First, the adhesive composition of the present invention is an adhesive composition used for performing adhesion using so-called adhesive force (adhesive force in a narrow sense not including adhesion), and sticking (adhesion using adhesive force). ) Is included in the pressure-sensitive adhesive composition (pressure-sensitive adhesive composition). Therefore, in the present specification, the term “adhesive” or “adhesive composition” simply means an adhesive (adhesive composition) in a broad sense including a pressure-sensitive adhesive (pressure-sensitive adhesive composition). To do.

When the term "hot melt adhesive (hot melt adhesive composition)" is used in the present specification, the adhesive (adhesive composition) is melted by heating and the adhesive (adhesive composition) is melted. ) Is applied to an adherend to solidify the adhesive (adhesive composition) at a low temperature, and the adhesive (adhesive composition) is used for adhesion. Further, in the present specification, when the terms "pressure-sensitive adhesive (pressure-sensitive adhesive composition)" and "adhesive (adhesive composition)" are used, the adhesive force of the adhesive is used for adhesion (adhesion). Means an adhesive (adhesive composition) used in. And, in particular, the “hot-melt pressure-sensitive adhesive (adhesive composition)” and the “hot-melt pressure-sensitive adhesive (pressure-sensitive adhesive composition)” in the present specification mean
When manufacturing an adhesive product such as an adhesive tape or an adhesive sheet by applying an adhesive (adhesive composition) to a substrate such as paper, cloth or plastic film, the adhesive is applied to the substrate in a state of being heated and melted. And an adhesive (adhesive composition) capable of forming a layer of a pressure-sensitive adhesive (pressure-sensitive adhesive composition; pressure-sensitive adhesive) on a substrate.

The adhesive composition of the present invention contains the specific block copolymer (a) as a base polymer, and the tackifying resin (b) as an essential component together with the base polymer. In the adhesive composition of the present invention, the block copolymer (a), (i) the block copolymer (a) is a polymer block A composed of a hydrogenated butadiene polymer (hereinafter simply referred to as “block A”). 1), at least one polymer block B composed of an aromatic vinyl compound (hereinafter simply referred to as “block B”), and a substantially olefin polymer structure different from the block A. It has at least one polymer block C composed of a polymer (hereinafter simply referred to as “block C”); (ii) the block A in the block copolymer (a) is
In the state before hydrogenation, the vinyl bond content is 20% or less; (iii) the block C in the block copolymer (a) has a glass transition temperature of -20 ° C or less and a heat of crystal fusion of 8c.
and (iv) in the block copolymer (a), the content of the block A before the hydrogenation treatment is based on the total weight of the block copolymer (a) before the hydrogenation treatment. It is 3 to 50% by weight;

The polymerization mode of butadiene is 4 of butadiene.
1,4-bonds in which all of the carbon atoms are incorporated into the main chain of the polymer and only two carbon atoms of butadiene are incorporated into the main chain of the polymer and the remaining two carbon atoms are side chains or Although there is a 1,2-bond (3,4-bond) (that is, a vinyl bond) that becomes a branched chain, in the adhesive composition of the present invention, the block A constituting the block copolymer (a) is a hydrogen atom thereof. 1,2-bond (3,4-bond) in the state before addition
Of the vinyl bond, that is, the vinyl bond content is 20% or less [Requirement (ii) above]. If the amount of vinyl bonds in the block A before hydrogenation (hereinafter sometimes referred to as “unhydrogenated block A”) exceeds 20%, the crystallinity of the block copolymer (a) decreases, and Polymer
The holding power of the adhesive composition containing (a) becomes low, resulting in poor adhesiveness (adhesiveness). In order to obtain an adhesive composition having excellent adhesiveness (tackiness), a block copolymer is used.
The vinyl bond amount in block A constituting (a) is 15
% Or less is preferable.

In the block A, the hydrogenation rate (hereinafter referred to as "hydrogenation rate") is preferably 70% or more, and more preferably 80% or more. When the hydrogenation rate of the block A is less than 70%, the block copolymer
The crystallinity of (a) is lowered, the holding power of the adhesive composition containing the block copolymer (a) is lowered, and the adhesiveness (tackiness) is apt to be lowered. It tends to be inferior in heat aging resistance and weather resistance.

Further, the block B constituting the block copolymer (a) is a block made of a polymer obtained by polymerizing an aromatic vinyl compound, and as the aromatic vinyl compound constituting the block B, For example, styrene, o-
Styrene, p-styrene, pt-butylstyrene,
1,3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene and the like can be mentioned. Even if the block B is composed of one kind of aromatic vinyl compound, or two or more kinds of aromatic vinyl compounds. It may be composed of Block B
Is preferably a polymer block of styrene.

Further, the block C constituting the block copolymer (a) is a polymer block different from the block A, and it is necessary that the block C substantially has an olefin polymer structure. Here, "the block C substantially has an olefin polymer structure" means that the block C is formed of a polymer of isobutylene, propylene, ethylene or other α-olefin monomer, and / Or isoprene, 2,3-dimethyl-1,3-
It means that it is substantially formed from a polymer obtained by hydrogenating a polymer of a conjugated diene such as butadiene, 1,3-pentadiene, 1,3-hexadiene, and butadiene. In this state, the polymer may have substantially the same structure as the polymer obtained by polymerizing the α-olefins. For example, the hydrogenated isoprene polymer block has substantially the same structure as the propylene / ethylene copolymer block, and therefore the hydrogenated isoprene polymer block is referred to as "substantially" in the present invention. Corresponds to a type of polymer block having an olefin polymer structure.

Incidentally, the hydrogenated butadiene polymer block also has substantially the same structure as the polyethylene block, and falls within the category of "polymer block having substantially olefin polymer structure". Can be included,
In the block copolymer (a) used in the adhesive composition of the present invention, it is necessary that the block C is composed of a polymer block different from the block A because of its structure. The vinyl bond content is 20%
The following blocks of butadiene polymer are not included.

Block C uses one or more monomers selected from the above-mentioned α-olefins and conjugated dienes unless they are hydrogenated butadiene polymer blocks having a vinyl bond content of 20% or less. When a conjugated diene is used, it may be hydrogenated to form an olefin polymer structure. When the block C is formed of two or more kinds of the above-mentioned monomers, the polymerization form thereof may be random, block or tapered, but is preferably random. Further, although not limited, the block C is, for example, an ethylene / propylene alternating copolymer, an ethylene / propylene random copolymer,
It can be formed from blocks such as ethylene / isobutylene random copolymer, hydrogenated isoprene polymer, hydrogenated isoprene / butadiene copolymer,
Among them, the hydrogenated isoprene polymer or the hydrogenated isoprene-butadiene copolymer is preferable from the viewpoint of the adhesive strength of the adhesive composition.

When the block C is formed by using a conjugated diene, the vinyl bond amount (that is, 1,2-bond amount and 3,4-bond amount) is 50% or less before hydrogenation. Is preferred. When the vinyl bond content in the block C exceeds 50%, the low temperature properties of the adhesive composition containing such a block copolymer are likely to be poor. When the block C is formed by using a conjugated diene, its hydrogenation rate is preferably 70% or more, more preferably 80% or more. When the hydrogenation rate is less than 70%, the adhesive composition tends to have poor heat aging resistance and weather resistance. Also,
As long as the block C does not impair properties such as heat aging resistance of the adhesive composition, a small amount (usually less than 30% by weight) of a structural portion other than the olefin polymer structure (for example, hydrogenated conjugated diene) is used as necessary. A non-structural portion, a structural portion derived from another monomer other than the hydrogenated structural portion of the olefin monomer and the conjugated diene monomer).

Further, in the present invention, the glass transition temperature of the block C constituting the block copolymer (a) is −20.
It is necessary that the temperature is not higher than 0 ° C and the heat of fusion of crystal is not higher than 8 cal / g [Requirement (iii) above]. When the glass transition temperature of the block C is higher than -20 ° C, the rubber elasticity of the block copolymer (a) is lowered, and the flexibility of the adhesive composition at low temperature becomes poor, and the crystal of the block C is also formed. When the heat of fusion exceeds 8 cal / g, the block copolymer (a)
The flexibility and low temperature properties of the adhesive at room temperature deteriorate, and the adhesive composition becomes brittle at low temperature. From the viewpoint of flexibility and low-temperature characteristics of the adhesive composition, the glass transition temperature of the block C is -30 ° C or lower, and the heat of crystal fusion is 5 or less.
It is more preferably cal / g or less. Here, the glass transition temperature of the block C referred to in the present invention means the value of the glass transition temperature of the block C portion measured by DSC (scanning differential calorimetry) for the block copolymer after hydrogenation, The details are as described in the Examples section below. Further, the heat of fusion of crystal of block C in the present invention means DS for the block copolymer after hydrogenation.
The heat of crystal fusion of the block C portion measured by C, the details of which are as described in the section of Examples below.

In the adhesive composition of the present invention, in the block copolymer (a), in the state before hydrogenation, the block A before hydrogenation (hereinafter referred to as "unhydrogenated block A") is used.
Content) of the block copolymer before hydrogenation
It must be 3 to 50% by weight, based on the total weight of (a) [Requirement (iv) above]. The content of the unhydrogenated block A is preferably 5 to 40% by weight. The content of unhydrogenated block A in the block copolymer (a) is 3
If it is less than wt%, the adhesive composition will have insufficient holding power, and if the content of the unhydrogenated block A in the block copolymer (a) exceeds 50 wt%, the adhesive composition will have poor adhesive strength (tack). Power) is insufficient and it does not fully function.

In the adhesive composition of the present invention, the content of the block B before hydrogenation in the block copolymer (a) is based on the total weight of the block copolymer (a) before hydrogenation. 5 to 20% by weight, and the content of block C before hydrogenation is 92 to 30% by weight, based on the total weight of the block copolymer (a) before hydrogenation, The total content of block B before addition and block C before hydrogenation is preferably 50 to 97% by weight.

The molecular weights of block A, block B and block C in the block copolymer (a) and the molecular weight of the block copolymer (a) are not particularly limited,
In the state before hydrogenation, the block A has a number average molecular weight of 2,500 to 200,000, preferably 3,000.
To 50,000, and the block B has a number average molecular weight of 1,000 to 100,000, preferably 3,000 to
20,000 and the number average molecular weight of block C is 3
30,000 to 300,000, preferably 50,000
~ 200,000 and block copolymer (a)
Has a number average molecular weight of 10,000 to 1,000,000,
It is preferably 20,000 to 300,000 in terms of processability of the adhesive composition.

The block copolymer (a) has at least one block A and at least one block B.
As long as it has one and at least one block C, the number of bonds of the block A, the block B and the block C in the block copolymer (a) and the bonding form are not particularly limited, and the blocks A, B and The blocks C may be linearly bonded or may be branched (radially) bonded. In addition, the bonding order of the blocks in the block copolymer (a) is not particularly limited. The block copolymer (a) is, for example, but not limited to, the following formulas;

[0026]

Embedded image A-B-C A-C-B B-A-C A-B-C-A A-B-C-B B-A-C-A B-A-C-B A-B -C-B-A A-C-B-C-A (wherein A represents block A, B represents block B, and C represents block C) and many other block copolymers represented by Block copolymers are included.

Among them, the block copolymer (a) is
A block copolymer having a structure in which block B is interposed between block A and block C (for example, the above formula,
From the viewpoint of the adhesive strength of the adhesive composition, the block copolymer represented by the formula (1) is preferable, and the block copolymer represented by the above formula is particularly preferable.

The block copolymer (a) has a carboxyl group, an acid anhydride group, a hydroxyl group, an epoxy group at the molecular end and / or the molecular chain, as long as the above-mentioned object of the present invention is not impaired. You may have functional groups, such as a group, an amino group, and a halogen atom.

The method for producing the block copolymer (a) is not particularly limited, and examples include anion polymerization, cationic polymerization, Ziegler-catalyzed polymerization, single-site polymerization, radical polymerization, and the like. A method of producing a block copolymer of C and subjecting it to a hydrogenation treatment by an appropriate method can be mentioned.

More specifically, the block copolymer (a) can be produced, for example, as follows, although not limited thereto. (1) (i) An alkyllithium compound having an alkyl group having 1 to 10 carbon atoms (preferably ethyllithium, n-
Propyllithium, sec-butyllithium, t-butyllithium, etc.) is used as a polymerization initiator to sequentially polymerize butadiene, an aromatic vinyl compound, and a monomer constituting the block C to obtain a block A and a block B before hydrogenation. Or block C using a dilithium compound (eg hexamethylenedilithium, naphthalenedilithium, oligostyryldilithium, dilithiostyrylbenzene, etc.) as a polymerization initiator. The monomers that make up
After the aromatic vinyl compound and butadiene are sequentially polymerized to produce a block copolymer having block C, block B and block A, (2) the block copolymer obtained in (1) above is converted into a hydrogenation catalyst ( For example, hydrogenation by a known method in which hydrogen is reacted in the presence of a noble metal catalyst such as platinum or palladium, Raney nickel, an organonickel compound, an organocobalt compound, or a complex catalyst of these compounds with another organometallic compound) The block copolymer (a) can be obtained by treating and recovering the hydrogenated block copolymer obtained thereby.

In the above-mentioned method for producing the block copolymer (a), the polymerization reaction of (1) is preferably carried out by adding a polymerization initiator of 0.1 part by weight to 100 parts by weight of all monomers.
Used in an amount of 01 to 0.3 parts by weight, an organic solvent inert to the polymerization initiator (eg, butane, pentane, n-hexane, isopentane, heptane, aliphatic hydrocarbons such as octane, cyclopentane, methyl Cyclopentane,
Alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, or aromatic hydrocarbon solvents such as benzene, toluene and xylene) are used at a temperature of -20 to 80 ° C for 1 to 50 hours. The hydrogenation reaction (2) is carried out under a hydrogen pressure of atmospheric pressure to 200 kg / cm ² at a reaction temperature of room temperature to 250 ° C. for 0.1 to 100 hours. The block copolymer (a) obtained by the hydrogenation reaction may be dried by heating or vacuum drying after solidifying the block copolymer (a) from the liquid by adding methanol or the like to the reaction liquid. The solution can be recovered by pouring the solution into boiling water to remove the solvent by azeotropic distillation, followed by heat drying or vacuum drying.

The adhesive composition of the present invention contains the tackifying resin (b) together with the base polymer comprising the block copolymer (a) described above. This tackifying resin (b) is
Mainly used to impart hot tack property to adhesive compositions (hot melt adhesives and hot melt type pressure sensitive adhesives) and at the same time lower the melt viscosity to improve workability such as coating work. In the adhesive composition of the present invention, as the tackifying resin (b), any of the tackifying resin (b) used in the conventional hot melt adhesive or hot melt pressure-sensitive adhesive is used. Can be used.

Examples of the tackifying resin (b) usable in the adhesive composition of the present invention include coumarone-indene resin,
Phenol resin, p-tertiary-butylphenol acetylene resin, phenol formaldehyde resin, terpene phenol resin, polyterpene resin, xylene formaldehyde resin, synthetic polyterpene resin, aromatic hydrocarbon resin, aliphatic hydrocarbon resin, mono Olefin and diolefin oligomer resin, hydrogenated terpene resin, hydrogenated aromatic hydrocarbon resin, hydrogenated aliphatic hydrocarbon resin, alicyclic saturated hydrocarbon resin, polybutene, polyhydric alcohol ester of rosin, water Examples thereof include hydrogenated rosin, hydrogenated wood rosin, esters of hydrogenated rosin with monoalcohol or polyhydric alcohol, and turpentine tackifier resins. These tackifier resins may be used alone or in combination of two or more. You may use together. Among them, in the present invention, as the tackifying resin (b), hydrogenated terpene resin, hydrogenated aromatic hydrocarbon resin, hydrogenated aliphatic hydrocarbon resin, alicyclic saturated hydrocarbon resin are preferably used. .

In the adhesive composition of the present invention, the tackifying resin
(b) with respect to 100 parts by weight of the block copolymer (a),
It is preferably used in a proportion of 10 to 2000 parts by weight, more preferably 40 to 500 parts by weight. When the use ratio of the tackifying resin (b) is less than 10 parts by weight described above, the adhesive strength (adhesive strength) of the adhesive composition
Of less than 2000 parts by weight,
The flexibility and the holding power at low temperatures are lowered, which is not preferable in any case.

Block copolymer (a) and tackifying resin
The adhesive composition comprising the two members (b) has excellent adhesive strength and can be used as a hot melt adhesive as it is. Further, this adhesive composition usually has an adhesive force at room temperature and can be used as a hot-melt type pressure-sensitive adhesive. However, when it is used as a hot melt adhesive (hot melt adhesive composition), the block copolymer (a) and the tackifying resin are used.
It is preferable to add wax to (b). By adding a wax to the adhesive composition comprising the block copolymer (a) and the tackifying resin (b), the adhesiveness of the adhesive composition at room temperature is reduced or eliminated to handle it as a hot melt adhesive. The adhesive composition (hot melt adhesive) open time (bonding possible time), softening point, hardness, hot tack property. The physical properties such as blocking property can be adjusted to appropriate ones, and the adhesive composition can be provided with performance suitable as a hot melt adhesive.

The wax used in hot melt adhesives has a melting point of 40 to 160 ° C.
Is preferably used, and examples of such a wax include paraffin wax, microcrystalline wax, Fischer-Trop wax, polyethylene wax, modified wax, and α-olefin wax, which have a melting point of 40 to 160 ° C. You can list the following. The wax may be used alone or in combination of two or more. Among the above waxes, paraffin wax is preferably used in the adhesive composition (hot melt adhesive) of the present invention.

The amount of wax used is the block copolymer.
(a) It is preferably 0 to 500 parts by weight, and more preferably 0 to 300 parts by weight, relative to 100 parts by weight. An adhesive composition (hot melt adhesive) obtained when the amount of wax used is more than 500 parts by weight as described above.
The adhesive strength of.

On the other hand, when it is used as a hot-melt pressure-sensitive adhesive, the tackiness of the adhesive composition (pressure-sensitive adhesive) is further increased, and the handling property as a pressure-sensitive adhesive is improved. For this purpose, a softening agent (plasticizer) conventionally used in pressure-sensitive adhesives may be further added.
In that case, the kind of the softening agent is not particularly limited, and any of the softening agents (plasticizers) conventionally used for pressure-sensitive adhesives can be used. For example, di- (2-ethylhexyl) phthalate is typical. Phthalic acid derivative, mineral oil softener,
Vegetable oil-based softeners, lanolin, liquid polybutene, liquid polyacrylates and the like can be used, and these softeners may be used alone or in combination of two or more kinds. Among them, in the adhesive composition of the present invention, a mineral oil-based softening agent is preferably used as the softening agent. The amount of the softening agent used is preferably 0 to 1000 parts by weight, and 0 to 3 parts by weight with respect to 100 parts by weight of the block copolymer (a).
More preferably, it is 00 parts by weight. If the amount of the softening agent used is more than 1000 parts by weight, the bleeding becomes severe and the quality of the pressure-sensitive adhesive deteriorates.

The pressure-sensitive adhesive composition and the pressure-sensitive adhesive product such as a pressure-sensitive adhesive tape or pressure-sensitive adhesive film produced using the pressure-sensitive adhesive composition are used by temporarily adhering them to an object and peeled off neatly after use. The pressure-sensitive adhesive composition therefore has a wide variety of usage modes and applications, including those required to be adhered to an object semipermanently without being peeled off. (Adhesives) and adhesive properties required for adhesive products (adhesive strength), tackiness, holding power, etc. have various physical properties, and values such as adhesive strength (adhesive power), tackiness, holding power are large. It is widely known that it is not always as good as it is. Therefore, in preparing the pressure-sensitive adhesive composition of the present invention,
Depending on the application and usage of the pressure-sensitive adhesive composition, the content, type, blending ratio and other components of the above block copolymer (a) and tackifying resin (b) may or may not be blended. It is necessary to appropriately select the type, the type, the blending amount, and the like, and adjust the properties such as the adhesive force (adhesive force), the tackiness, and the holding force to be suitable for each application or usage mode.

In the adhesive composition of the present invention, in addition to the above components, compounding agents such as antioxidants and ultraviolet absorbers for improving heat resistance and weather resistance are preferably used. Further, if necessary, the adhesive composition of the present invention may contain a filler such as calcium carbonate and titanium oxide, and a fibrous material such as glass fiber and organic fiber.
Further, the adhesive composition of the present invention is an unhydrogenated styrene / butadiene-based block copolymer, a hydrogenated styrene / block-based block copolymer, if necessary, as long as the above-mentioned characteristics of the present invention are not lost. , Other polymers such as ethylene / vinyl acetate copolymer may be contained.

The method for preparing the adhesive composition of the present invention is not particularly limited, and the above-mentioned block copolymer (a) and tackifying resin are used.
Any method can be adopted as long as it can uniformly mix (b) and other components used as necessary, and examples thereof include a high-speed stirrer, a kneader, a melting pot, an internal mixer, a single-screw extruder and a twin-screw extrusion. It can be prepared by melt-mixing or melt-kneading using an extruder such as a machine. The adhesive composition of the present invention obtained by mixing the above-mentioned components can be put in an appropriate form depending on its use, usage, etc., for example, block-like, granular, flake-like, pellet-like. It can be used in the form of a stick, a film, a sheet, or the like for their respective adhesive applications and the production of various adhesive products.

Further, the application of the adhesive composition of the present invention is not particularly limited, and it can be used for adhesion and application of various materials like conventional hot melt adhesives and hot melt type pressure sensitive adhesives. For example, it can be used for adhesion of plastic films and sheets of polyethylene, polypropylene, polyester, etc., paper, wood, textile products, metal foil, leather, etc. More specifically, the adhesive composition of the present invention is used in packaging such as bag making, box / cardboard sealing, label pickup, aluminum foil can manufacturing, bookbinding, plywood manufacturing, woodworking, and the like. Manufacturing of shoes; Fabrication of textile products such as sewing, carpet backing, and non-woven binders; Production of various hygiene products such as paper diapers; Adhesive tapes for packaging; Electrical insulating tapes and films; Adhesive tapes and adhesives for surface protection of various articles It can be used as a sheet; various adhesive films and adhesive sheets used in the semiconductor wafer manufacturing process; binding and fixing of pipes and the like; sealing material; adhesive for labels and the like.

When the adhesive composition of the present invention is a hot-melt adhesive, the hot-melt adhesive is heated and melted using an applicator for hot-melt adhesive as in the prior art. The adhesive can be applied to the body and adhered by solidifying the adhesive in a state where the adherends are adhered (compressed) to each other. When the adhesive composition of the present invention is a hot-melt pressure-sensitive adhesive (adhesive), the hot-melt pressure-sensitive adhesive is heated and melted in the form of paper, cloth, plastic film or sheet, A pressure-sensitive adhesive (adhesive) layer may be formed by applying it to one or both sides of a substrate such as a metal foil to produce an adhesive film, an adhesive sheet, or other adhesive products. it can. The adhesive of the present invention is used both in the case where the adhesive composition of the present invention is a hot-melt adhesive and in the case of a hot-melt pressure-sensitive adhesive composition (hot-melt adhesive). The composition can usually be easily melted by heating to a temperature of about 120-200 ° C,
Moreover, since its melt viscosity does not change significantly even if the temperature changes to some extent, it is possible to smoothly carry out the bonding work and the manufacturing work of an adhesive product such as an adhesive film with good processing stability.

[0044]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In the following examples, the number average molecular weight of the block copolymer before hydrogenation in the block copolymer (a) used for the preparation of the adhesive composition, the number average molecular weight of the butadiene polymer block (block A) before hydrogenation Molecular weight, number average molecular weight of styrene polymer block (block B), number average molecular weight of isoprene polymer block before hydrogenation or butadiene / isoprene copolymer block (block C) before hydrogenation, block copolymer (a ), Content of block A before hydrogenation, content of block B, amount of vinyl bond in block A before hydrogenation, block A
The hydrogenation rate of block C, the glass transition temperature of block C, and the heat of crystal fusion of block C were determined as follows.

Block copolymer, block A, block
Number average molecular weight of B and block C : With respect to the block copolymer before hydrogenation, the number average molecular weight of the entire block copolymer was determined as a molecular weight in terms of polystyrene by GPC analysis. The number average molecular weights of block A, block B and block C were calculated from the number average molecular weight of the entire block copolymer and the charged amounts of the monomer for block A, the monomer for block B and the monomer for block C. .

The block copolymer before hydrogenation in the block copolymer
The content of lock A and block B: in the production of the block copolymer, charged amount of the monomer (butadiene) of block A (W _A), charged amount of the monomer (styrene) for the block B (W _B) And the charged amount (W _C ) of the monomer for block C (isoprene or isoprene and butadiene), the following mathematical formula;

[0047]

## EQU1 ## Content of block A (% by weight) = {W _A / (W _A
+ W _B + W _C )} × 100 Block B content (% by weight) = {W _B / (W _A + W _B +
W _C )} × 100 [wherein, W _A = total charged amount of monomer for block A (weight) W _B = total charged amount of monomer for block B (weight) W _C = total amount of monomer for block C Charged amount (weight)]
The content of block A and block B before hydrogenation in the block copolymer before hydrogenation treatment was determined by.

Vinyl binding in block A before hydrogenation
Total amount : The block copolymer before hydrogenation treatment obtained by polymerization was subjected to NMR analysis to determine the amount of vinyl bonds in block A before hydrogenation.

Hydrogenation rate of block A and block C : The hydrogenation rate of each of block A and block C was determined by subjecting the block copolymer after hydrogenation treatment to NMR analysis.

Glass transition temperature of block C : DSC (scanning differential thermal measurement) of the block copolymer after hydrogenation treatment
Then, the top peak value of the differential curve of the endothermic peak was obtained and used as the glass transition temperature of block C.

Heat of crystal fusion of block C : The block copolymer after hydrogenation was subjected to DSC (scanning differential calorimetry) to determine the endothermic peak curve corresponding to block C per unit weight of the block copolymer (a). Area was determined and used as the heat of crystal fusion of block C.

Reference Example 1 [Production of Hydrogenated Pentablock Copolymer] (1) 3500 ml of cyclohexane was placed in a pressure resistant reactor (internal volume of 5 liters) and purged with dry nitrogen, and then n-butyllithium 0.8g, then butadiene 45g, temperature 50 ℃, pressure 1kg / cm
It was polymerized for 2 hours under the conditions of ^2. (2) Next, 75 g of styrene was charged in the reactor and polymerized for 3 hours under the conditions of a temperature of 50 ° C. and a pressure of 1 kg / cm ² , and then 360 g of isoprene was charged in the reactor at a temperature of 50 ° C. Polymerization was carried out for 5 hours under a pressure of 1 kg / cm ² . (3) Further, 75 g of styrene was charged again in the reactor and polymerized for 2 hours under the conditions of a temperature of 50 ° C. and a pressure of 1 kg / cm ² , and then 45 g of butadiene was charged to a temperature of 50 ° C.
Polymerize for 2 hours under conditions of ℃ and pressure of 1 kg / cm ² ,
Production of pentablock copolymer consisting of block A-block B-block C-block B-block A (i.e. butadiene polymer block-styrene polymer block-isoprene polymer block-styrene polymer block-butadiene polymer block) did. Regarding the obtained pentablock copolymer, the number average molecular weight of the block copolymer, the number average molecular weights of block A, block B and block C, the content of block A before hydrogenation in the block copolymer, The content and the vinyl bond amount in the block A before hydrogenation were determined by the above-mentioned method and were as shown in Table 1 below. (4) 500 g of the pentablock copolymer obtained in (3) above was placed in a pressure-resistant container having a capacity of 5 liters, and 10 parts by weight of a hydrogenation catalyst (Raney nickel) was added to 100 parts by weight of the pentablock copolymer. And hydrogen pressure 50kg /
Hydrogenation reaction was carried out for 10 hours under conditions of cm ² and temperature of 100 ° C. to produce a hydrogenated pentablock copolymer. The hydrogenation ratios of block A and block C, and the glass transition temperature and heat of crystal fusion of block C in the obtained hydrogenated pentablock copolymer were determined by the above-mentioned methods and are as shown in Table 1 below. It was

Reference Example 2 [Production of Hydrogenated Pentablock Copolymer] In the second polymerization step of Reference Example 1 (2), instead of using isoprene, butadiene and isoprene
Polymerization was performed in the same manner as in (1) to (3) of Reference Example 1 except that a mixture having a weight ratio of 0/30 was used, and Table 1 below.
Number average molecular weight, content of block A before hydrogenation, content of block B and block A before hydrogenation shown in
Block A-Block B-Block C-Block B-Block A (i.e., butadiene polymer block-styrene polymer block-butadiene / isoprene copolymer block-styrene polymer block-butadiene polymer block) having vinyl bond content in After the production of the pentablock copolymer consisting of the above), the obtained pentablock copolymer was subjected to hydrogenation treatment in the same manner as in (4) of Reference Example 1, and the hydrogenation rate shown in Table 1 below. , And block C (butadiene / isoprene polymer block)
A hydrogenated pentablock copolymer having a glass transition temperature and a heat of fusion of crystal was prepared.

[0054]

[Table 1]

Example 1 (1) A tackifying resin was added to 100 parts by weight of the hydrogenated pentablock copolymer obtained in Reference Example 1 above.
(Alicyclic hydrocarbon resin: "Alcon P100" manufactured by Arakawa Chemical Co., Ltd.) 100 parts by weight, wax (paraffin wax: Paraffin wax 15 manufactured by Nippon Wax Co., Ltd.)
5 ") 50 parts by weight and an antioxidant (hindered / phenolic:" Irganox 101 "manufactured by Ciba Geigy)
0 ") 1 part by weight was added and melt-mixed at a temperature of 170 ° C using a kneader to produce a hot-melt adhesive composition. (2) Prepare two sheets of the hot melt adhesive composition obtained in (1) above, which are heated to 160 ° C. to be melted and applied on one surface of an aluminum plate having a thickness of 0.5 mm to a thickness of 50 μm. Then, two aluminum plates are laminated with the adhesive coated surfaces facing each other, and a heat sealer ("SG600" manufactured by Shiga Packing Machine Co., Ltd.
R ”) was adhered under the conditions of a temperature of 180 ° C. and a pressing time of 1.2 seconds to produce a laminated plate. (3) The adhesive strength of the laminate obtained in (2) above was determined according to JIS Z0237. That is, the T-type peel test was performed at an ambient temperature of 25 ° C. at a peel rate of 300 mm /
The adhesive strength was determined under the condition of minutes. The results are shown in Table 2 below. (4) A plate-shaped test piece of length × width × thickness = 10 mm × 60 mm × 2 mm was prepared using the hot melt adhesive obtained in (1) above, and the test piece was placed in a -15 ° C. freezer. After leaving it overnight, take it out, bend it by hand immediately after taking it out, and mark it as unmarked as ○, cracked as ×,
When the low temperature characteristics were evaluated, it was as shown in Table 2 below. (5) Using the hot melt adhesive composition obtained in (1) above, length x width x thickness = 10 mm x 10 mm x 1 m
A plate-shaped test piece of m was prepared, and this test piece was immersed in JIS No. 3 oil at room temperature for 10 days, then taken out, and the weight of the test piece before and after immersion in oil was measured. When the degree of swelling (%) was calculated and the oil resistance was evaluated, the results are shown in Table 2 below.

[0056]

Swelling degree (%) = {(ED) / D} × 100 [wherein, D = weight of test piece before immersion in oil (mg) E = test piece after immersion in oil] Weight (mg)]

Example 2 (1) The hydrogenated pentablock copolymer obtained in Reference Example 2 was used in place of the hydrogenated pentablock copolymer obtained in Reference Example 1. After producing a hot melt adhesive composition in the same manner as in (1) of Example 1, a laminated board was produced in the same manner as in (2) of Example 1, and the adhesive strength was measured as in Example 1 ( When measured in the same manner as 3), the results are shown in Table 2 below. (2) Using the hot melt adhesive composition obtained in (1) above, a test piece was produced in the same manner as in (4) and (5) of Example 1 to obtain its low temperature characteristics and oil resistance. When examined in the same manner as in (4) and (5) of Example 1,
The results are shown in Table 2 below.

Comparative Example 1 (1) Instead of the hydrogenated pentablock copolymer obtained in Reference Example 1, hydrogenated styrene polymer block-isoprene polymer block-styrene polymer block was added. The hot-melt adhesive composition was produced in the same manner as in (1) of Example 1 except that the triblock copolymer (“Septon 2002” manufactured by Kuraray Co., Ltd.) was used. A laminated board was produced in the same manner as in 2), and the adhesive strength thereof was measured in the same manner as in (3) of Example 1, and the results are shown in Table 2 below. (2) Using the hot melt adhesive composition obtained in (1) above, a test piece was produced in the same manner as in (4) and (5) of Example 1 to determine its low temperature specification and oil resistance. When examined in the same manner as in (4) and (5) of Example 1,
The results are shown in Table 2 below.

Comparative Example 2 (1) Instead of the hydrogenated pentablock copolymer obtained in Reference Example 1, a commercially available ethylene / vinyl acetate copolymer [“EVA25” manufactured by Mitsui DuPont Chemical Co., Ltd.] was used.
0 "] was used, a hot melt adhesive composition was produced in the same manner as in (1) of Example 1, and then Example 1 was used.
A laminate was produced in the same manner as in (2) above, and its adhesive strength was measured in the same manner as in (3) of Example 1 and was as shown in Table 2 below. (2) Using the hot melt adhesive composition obtained in (1) above, a test piece was produced in the same manner as in (4) and (5) of Example 1 to determine its low temperature specification and oil resistance. When examined in the same manner as in (4) and (5) of Example 1,
The results are shown in Table 2 below.

[0060]

[Table 2]

From the results of Table 2 above, the above (i) to
Example 1 and Example 2 obtained by using the block copolymers of Reference Example 1 and Reference Example 2 satisfying the requirement of (iv)
The hot-melt adhesive composition of Comparative Example 1 is excellent in comparison with the hot-melt adhesive composition of Comparative Example 1 based on a block copolymer composed of a hydrogenated styrene polymer block-isoprene polymer block-styrene polymer block. It can be seen that it has adhesiveness. Further, it can be seen that the hot melt adhesive compositions of Examples 1 and 2 are excellent in low-temperature characteristics and extremely excellent in oil resistance, and have a low degree of swelling even when immersed in oil for a long period of time.

[0062]

The adhesive composition of the present invention is excellent in solvent resistance and oil resistance, and is also excellent in other characteristics such as adhesiveness, tackiness, holding power, low temperature characteristics and flexibility. Utilizing these characteristics, it can be effectively used in a wide range of applications such as packaging, bookbinding, plywood manufacturing, woodworking, shoes manufacturing, adhesion of textile products, various adhesive tapes, various adhesive products such as labels, etc. be able to.

Further, since the adhesive composition of the present invention can be used as a hot-melt type adhesive or a pressure-sensitive adhesive without using a solvent, it causes air pollution, fire hazard, working environment and hygiene. It does not cause problems such as surface deterioration and does not require the use of water unlike water-based adhesives, so it does not require drying time or a drying device, and adheres adherends in a short time after application of adhesive. Can be completed or the production of adhesive products can be completed, and it is also excellent in terms of energy saving, workability, and productivity.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikio Masuda 36 Higashiwada, Kamisu Town, Kashima-gun, Ibaraki Prefecture Kuraray Co., Ltd. (72) Hideo Takamatsu 2-3-10 Nihonbashi, Chuo-ku, Tokyo Kuraray Co., Ltd. Within

Claims (1)

[Claims] 1. An adhesive composition containing a block copolymer (a) and a tackifying resin (b), wherein (i) the block copolymer (a) comprises a hydrogenated butadiene polymer. A polymer comprising at least one united block A, at least one polymer block B comprising an aromatic vinyl compound, and a polymer having a substantially olefin polymer structure different from the polymer block A. (Ii) The polymer block A in the block copolymer (a) is obtained by hydrogenating a butadiene polymer block having a vinyl bond content of 20% or less; (iii) ) The glass transition temperature of the polymer block C in the block copolymer (a) is −20 ° C. or lower and the heat of crystal fusion is 8 cal / g or lower; and (iv) the block copolymer (a) , The content of the polymer block A before hydrogenation process, based on the total weight of the hydrogenation process prior to the block copolymer (a) 3 to 50 wt%
An adhesive composition comprising: