JPH06228522A - Hot-melt pressure-sensitive adhesive composition - Google Patents

Abstract

PURPOSE:To obtain a composition having a low melt viscosity and being excellent in the balance among initial tack, adhesiveness and holding power by adding a specified hydrocarbon resin to a specified block copolymer composition. CONSTITUTION:The composition is prepared by adding a hydrocarbon resin obtained by cationically polymerizing a monomer mixture comprising a 4-8C aliphatic monoolefin, a 4-5C aliphatic diolefin and an 8-10C aromatic monoolefin in the presence of a Friedel-Crafts catalyst to a block copolymer composition comprising a block copolymer of formula I, a block copolymer of formula II and a block copolymer of formula III. In the formulas, n is 3 or 4; A is a block of a polymer of an aromatic vinyl monomer, B is a block of a polymer of a conjugated diene monomer; X is a residue of a trifunctional or tetrafunctional coupling agent; and Y is a residue of a bifunctional or tetrafunctional coupling agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive composition for double-sided hot-melt tape.

[0002]

2. Description of the Related Art In recent years, solvent removal has progressed in the adhesive tape industry, and hot-melt adhesives based on styrene-isoprene block copolymer rubber (hereinafter referred to as SIS) have been developed mainly for packing tapes. Has been done. However, in the field of double-sided tape applications, which generally require a higher cohesive force than packaging applications, the use of an aliphatic hydrocarbon resin as a tackifier in conventional SIS makes it impossible to coat in the heat melting process. Showing high viscosity was a major obstacle.

[0003]

An object of the present invention is to provide a pressure-sensitive adhesive composition for a hot-melt double-sided tape which has a low melt viscosity and a high cohesive strength. Therefore, as a result of studies to achieve such an object, the present inventors have found that it is effective to use a specific aromatic hydrocarbon resin, and have completed the present invention.

[0004]

According to the present invention, the block copolymer (I) represented by the general formula (AB) _n X and the general formula (AB) ₂ Y are thus represented. Containing a block copolymer (II) and a block copolymer (III) represented by the general formula (AB) (wherein n = 3 or 4, A is an aromatic vinyl monomer). The polymer block of the body, B
Represents a polymer block of a conjugated diene monomer, X represents a residue of a trifunctional or tetrafunctional coupling agent, and Y represents a residue of a difunctional or tetrafunctional coupling agent. )
The weight of (I), (II) and (III) is (I) /
(II) = 5/95 to 95/5 and ((I) + (I
I)) / (III) = 45/55 to 95/5 The block copolymer composition (1) satisfying the relationship has 4 carbon atoms.
5 to 60% by weight of the aliphatic monoolefin (a) having 8 to 8%, 20 to 70% by weight of the aliphatic diolefin (b) having 4 or 5 carbon atoms and 8 to 10% of the aromatic monoolefin having 8 to 10 carbon atoms Adhesive for hot-melt double-sided tape, which comprises a hydrocarbon resin (2) obtained by cationically polymerizing a monomer mixture containing 5 to 40% by weight of olefin (c) in the presence of Friedel-Crafts catalyst. An agent composition is provided.

The block copolymer (I) of the block copolymer composition (1) used in the present invention has the general formula (AB).
A block copolymer represented by _n X, comprising a polymer block A of an aromatic vinyl monomer and a polymer block B of a conjugated diene monomer having a polymerization active terminal (A
It is a branched block copolymer having a structure in which the -B) type block copolymer is coupled with a trifunctional or tetrafunctional coupling agent.

The proportion of the polymer block A of the aromatic vinyl monomer in the block copolymer (I) is 5 to 50% by weight,
It is preferably 10 to 45% by weight. If this proportion is less than 5% by weight, the holding power will decrease, and if this proportion exceeds 50% by weight, the initial adhesive strength will decrease, which is not preferable.

The aromatic vinyl monomer for synthesizing the block copolymer (I) is not particularly limited,
Specific examples thereof include styrene, α-methylstyrene,
Examples thereof include vinyltoluene and vinylnaphthalene, with styrene being preferred.

The conjugated diene monomer for the synthesis of the block copolymer (I) is not particularly limited, and specific examples thereof include 1,3-butadiene, isoprene, 2,
3-dimethyl-1,3-butadiene, piperylene, 2,
4-hexadiene and the like can be mentioned, among which 1,3-butadiene and isoprene are preferable.

The polystyrene reduced weight average molecular weight of the block copolymer (I) is 50,000 to 500,000,
It is preferably 100,000 to 400,000. If the molecular weight is less than the lower limit, the holding power will be insufficient, and if it exceeds the upper limit, workability will be unsatisfactory.

The trifunctional or tetrafunctional coupling agent used in the synthesis of the block copolymer (I) is not particularly limited, but examples thereof include tin coupling agents such as methyltrichlorotin and tetrachlorotin; phenyl; Alkoxysilane coupling agents such as trimethoxysilane, phenyltriethoxysilane, tetramethoxysilane, tetraethoxysilane; silicon halide coupling agents such as silicon tetrachloride and tetrabromosilicon; chloroform, trichloroethane, trichloropropane, Examples thereof include halogenated alkanes such as tribromopropane. Above all, it is preferable to use an alkoxysilane-based coupling agent because it is possible to obtain a pressure-sensitive adhesive composition for a hot-melt double-sided tape which has an excellent balance of initial adhesive strength, holding power and processability.

The block copolymer (II) of the block copolymer composition (1) used in the present invention has the general formula (A-
B) A block copolymer represented by ₂ Y, comprising a polymer block A of an aromatic vinyl monomer and a polymer block B of a conjugated diene monomer having a polymerization active terminal (A- It is a block copolymer having a structure in which the B) type block copolymer is coupled with a bifunctional or tetrafunctional coupling agent.

The ratio of the polymer block A of the aromatic vinyl monomer in the block copolymer (II) is 5 to 50.
%, Preferably 10 to 45% by weight. If this proportion is less than 5% by weight, the holding power will decrease, and if this proportion exceeds 50% by weight, the initial adhesive strength will decrease.

The aromatic vinyl monomer and the conjugated diene-based monomer used in the block copolymer (II) are the same as those used in the synthesis of the block copolymer (I). be able to.

The polystyrene reduced weight average molecular weight of the block copolymer (II) is 50,000 to 500,000.
0, preferably 100,000 to 400,000. If the molecular weight is less than the lower limit, the holding power will be insufficient, and if it exceeds the upper limit, workability will be unsatisfactory.

Examples of the bifunctional to tetrafunctional coupling agent used in the synthesis of the block copolymer (II) include dichlorotin, monomethyldichlorotin, dimethyldichlorotin, monoethyldichlorotin, diethyldichlorotin and methyltrichloro. Tin, monobutyldichlorotin,
Tin-based coupling agents such as dibutyldibromotin, monohexyldichlorotin, tetrachlorotin;
Dichlorosilane, monomethyldichlorosilane, dimethyldichlorosilane, monoethyldichlorosilane, diethyldichlorosilane, monobutyldichlorosilane, dibutyldichlorosilane, monohexyldichlorosilane, dihexyldichlorosilane, dibromosilane, monomethyldibromosilane, dimethyldibromosilane, Silicon tetrachloride,
Silicon halide coupling agents such as tetrabromosilicon; alkoxysilanes such as diphenyldimethoxysilane, diphenyldiethoxysilane tetramethoxysilane; divinylaromatic compounds such as divinylbenzene and divinylnaphthalene; dichloroethane, dibromoethane,
Halogenated alkanes such as methylene chloride, dibromomethane, dichloropropane, dibromopropane, chloroform, trichloroethane, trichloropropane, tribromopropane; halogenated aromatic compounds such as dibromobenzene; benzoic acid ester, CO, 2-chloropropene, 1 -Other coupling agents such as chloro-1,3-butadiene; Among these, dibromobenzene and the like are preferable.

The block copolymer (III) of the block copolymer composition (1) used in the present invention has the general formula (A-
The block copolymer represented by B) is obtained by block-copolymerizing an aromatic vinyl monomer and a conjugated diene monomer.

The ratio of the polymer block C of the aromatic vinyl monomer in the block copolymer (III) is 5 to 50.
%, Preferably 10 to 45% by weight. If this proportion is less than 5% by weight, the holding power will decrease, and if this proportion exceeds 50% by weight, the initial adhesive strength will decrease.

The aromatic vinyl monomer and the conjugated diene-based monomer used in the block copolymer (III) include
The same monomers as those used for the synthesis of the block copolymer (I) are used.

The polystyrene reduced weight average molecular weight of the block copolymer (III) is 10,000 to 300,000.
It is 0, preferably 20,000 to 250,000. If the molecular weight is less than the lower limit, the retention will be insufficient,
Further, if it exceeds the upper limit, the workability becomes unsatisfactory.

The block copolymer composition (1) used in the present invention is composed of the block copolymer (I),
Between the weights of (II) and (III), (I) / (I
I) = 5/95 to 95/5, preferably (I) / (I
I) = 40/60 to 90/10, and ((I) + (I
I)) / (III) = 45/55 to 95/5, preferably ((I) + (II)) / (III) = 50/50 to
It is necessary for the relationship of 90/10 to be established. If it deviates from this range, the balance between the initial adhesive force and the holding force obtained will be unsatisfactory.

In the range not impairing the effects of the present invention, 5% by weight or less of the block copolymer composition (1) is a block copolymer other than the block copolymers (I) to (III), natural rubber, It can be replaced with other polymers such as butadiene rubber, isoprene rubber.

The block copolymer composition (1) used in the present invention is prepared by separately synthesizing the block copolymers (I), (II) and (III), and then synthesizing them by an arbitrary method. It may be obtained by mixing in a weight ratio, or a (AB) type in which a polymer block of a conjugated diene monomer having a polymerization active terminal is directly bonded to a polymer block of an aromatic vinyl monomer. When the block copolymer (1) is coupled, the type and amount of the coupling agent are controlled, and if necessary, a known coupling accelerator is used in combination, so that the block copolymer (I) to (III It is also possible to obtain a block copolymer mixture consisting of any two components of the above) and appropriately mixing these. Furthermore, according to the latter method, the block copolymer composition of the present invention can be obtained at one time.

The block copolymers (I) to (I) for obtaining the block copolymer composition (1) used in the present invention.
The mixing method of II) is not particularly limited, and a method of heating and mixing each component with a Brabender or a kneader can be exemplified.

Block copolymer (I) used in the present invention
The method of synthesizing is not particularly limited, but it can be prepared, for example, according to the following processes (a) to (d) described in JP-A-3-26747. That is, (a) First, an aromatic vinyl monomer is polymerized with a monolithium initiator in a solvent containing a polar compound. As the monolithium initiator, known ones capable of initiating polymerization of an aromatic vinyl monomer and a conjugated diene monomer can be used, and methyllithium, n-propyllithium, n-butyllithium, sec-butyllithium. And the like are shown as typical examples thereof, but n-butyllithium is particularly preferable. The amount of the monolithium initiator used can be calculated by a method well known to those skilled in the art according to the molecular weight of the desired polymer.

The polymerization solvent is not particularly limited as long as it is inert to the monolithium initiator.
An open chain hydrocarbon solvent, a cyclic hydrocarbon solvent or a mixed solvent thereof is used. As the open chain hydrocarbon solvent, n-butane, isobutane, or a mixture thereof; 1-butene, isobutylene, trans-2-butene, cis-2-
Butene or a mixture thereof, 1-pentene, trans-2-pentene, cis-2-pentene or a mixture thereof; n-pentane, isopentane, sec-pentane or a mixture thereof; 1-pentene, trans-2-pentene Examples include open chain alkanes and alkenes having 4 to 5 carbon atoms such as cis-2-pentene and mixtures thereof. Specific examples of the cyclic hydrocarbon solvent include aromatic compounds such as benzene, toluene and xylene; and alicyclic hydrocarbons such as cyclohexane. From the viewpoint of controlling the polymerization temperature and controlling the molecular weight distribution of the polymer block of the aromatic vinyl monomer, the open-chain hydrocarbon solvent having 4 to 5 carbon atoms and the cyclic hydrocarbon solvent are in a weight ratio of 5:95 to 50. It is preferable to use it as a mixed solvent in the range of: 50, preferably in the range of 10:90 to 40:60.

Further, it is not essential to use a polar compound, but by using it, the polymerization initiation rate is adjusted, the vinyl content of the polymer of the conjugated diene monomer is adjusted,
The molecular weight distribution of the polymer block of the aromatic vinyl monomer can be adjusted. As the polar compound, among known polar compounds used as a vinyl content modifier or randomizer in the copolymerization of a conjugated diene-based monomer or an aromatic vinyl monomer with a monolithium initiator, a relative dielectric Aromatic or aliphatic ethers or tertiary amines with a ratio of 2.5 to 5.0 can be used. Specific examples of such polar compounds include aromatic ethers such as diphenyl ether and anisole; aliphatic ethers such as diethyl ether and dibutyl ether;
Tertiary monoamines such as erymethylamine, triethylamine, and tripropylamine are mentioned.
One kind or two or more kinds are used. A preferable amount of the polar compound used in order to make the molecular weight distribution of the polymer block of the aromatic vinyl monomer to be a predetermined value and to make the characteristics of the pressure-sensitive adhesive composition containing the obtained block copolymer excellent. Is in the range of 0.1 to 100 mol, and more preferably 0.5 to 20 mol, per mol of the monolithium initiator.

The method for polymerizing the aromatic vinyl monomer is not particularly limited, and batch polymerization in which the total amount of the aromatic vinyl monomer and the total amount of the initiator are charged into a batch polymerization system and reacted, and these are continuously polymerized Continuous polymerization in which reaction is performed while being supplied to the system,
Any of commonly used methods, such as a method in which polymerization is carried out to a predetermined conversion rate using a part of the monomer and the initiator and then the remaining monomer and the initiator are added to continue the polymerization, You may use. The polymerization is usually 0 ° C to 90 ° C, preferably 2 ° C.
It is carried out in the range of 0 ° C to 70 ° C. When it is difficult to control the reaction temperature, it is preferable to control the temperature by reflux cooling using a reaction vessel equipped with a reflux condenser.

(B) Next, a conjugated diene monomer is added to the polymerization system in which the polymer block A of the aromatic vinyl monomer having a polymerization active terminal is present to carry out polymerization. The conjugated diene-based monomer is preferably added continuously in order to control the reaction heat, but an addition method other than this may be adopted. Thus, an (AB) type block copolymer in which the polymer block B of the conjugated diene-based monomer having a polymerization active terminal is directly bonded to the polymer block A of the aromatic vinyl monomer is produced.

(C) After the completion of the polymerization reaction of the conjugated diene-based monomer, a coupling agent is added to the polymerization system to bond the (AB) type block copolymer having an active terminal, The desired general formula (AB) ₃ X (wherein A is a polymer block of an aromatic vinyl monomer, B is a polymer block of a conjugated diene monomer, and X is a trifunctional or Four
A block copolymer represented by (representing the residue of the functional coupling agent) is obtained. At this time, a known coupling accelerator may be added.

(D) After completion of the coupling reaction, if necessary, water, alcohol, acid or the like is added to deactivate the polymerization active species, and if necessary, an antioxidant is added, and then a known polymer separation method is used. The polymer is separated by (for example, steam stripping), and the desired three-branched block copolymer or a mixture of this and a linear diblock copolymer is obtained through a drying step.

The block copolymer (I
I) is synthesized in the same manner as the block copolymer (I) except that the coupling agent used in the above step (C) is changed.

The block copolymer (II used in the present invention
In (I), the polymer block B of the conjugated diene monomer having a polymerization active terminal is an aromatic vinyl monomer in the same manner as in the synthesis processes (a) to (d) of the block copolymer (I). After obtaining the linear (AB) type block copolymer directly bonded to the polymer block A, the polymerization active species is deactivated as in the above process (D), and an antioxidant is added if necessary. And then separated without performing a coupling reaction,
It can be obtained through a drying process.

Block copolymer (I) used in the present invention
The optimum amount of the trifunctional or tetrafunctional coupling agent used is 1/3 mol based on 1 mol of the monolithium initiator used for the polymerization in order to obtain only a high yield. If the amount used is more than 1/3 mol, the second component co-produces, but if the amount is further increased, a linear block having a structure of (A-B-X) having a residue of the coupling agent at the terminal. A large amount of the copolymer (however, A, B, and X are the same as above) becomes rigid. The linear block copolymer having a structure of (A-B-X) having a coupling agent residue at the terminal easily hydrolyzes in the block copolymer production process, is difficult to steam solidify, and gels. In the present invention, the amount of the trifunctional or tetrafunctional coupling agent used is preferably 0.375 mol or less with respect to 1 mol of the monolithium initiator because some problems such as easiness occur.

When the method for temporarily obtaining the block copolymer composition (1) used in the present invention as described above is adopted, it can be obtained depending on the type and amount of the coupling agent and the coupling accelerator. Since the composition of the block copolymer mixture is different, it is recommended to conduct a preliminary experiment to determine the kind and the optimum amount of use, but normally, the amount of the coupling agent is 0.1% with respect to 1 mol of the monolithium initiator. From the range of 15 to 0.375 mol, the amount of the coupling accelerator is preferably selected from the range of 2 to 12 mol per mol of the coupling agent.

The hydrocarbon resin (2) used in the present invention is
Aliphatic monoolefin (a) 5 having 4 to 8 carbon atoms
˜60% by weight, 20 to 70% by weight of aliphatic diolefin (b) having 4 or 5 carbon atoms and 8 to 10 carbon atoms
5 to 40% by weight of aromatic monoolefin (c) having
It is obtained by cationically polymerizing a monomer mixture containing C in the presence of a Friedel-Crafts catalyst.

Aliphatic mono-olefins (a) having 4 to 8 carbon atoms include linear mono-olefins and alicyclic mono-olefins, and specific examples thereof include isobutylene, butene-1, cis. -Butene-2, trans-butene-2, pentene-1, cis-pentene-
2, trans-pentene-2,2-methyl-butene-
Examples are 1,2-methyl-butene-2, diisobutylene, cyclopentene, cyclohexene, and cyclopentene is particularly preferred. A pressure-sensitive adhesive composition using a hydrocarbon resin obtained by cationically polymerizing such an aliphatic monoolefin as a tackifier has an initial compatibility due to an improved compatibility with the block copolymer rubber composition (1). The adhesive strength is improved. However, if the ratio exceeds 60% by weight, the yield of the hydrocarbon resin obtained by cationic polymerization is lowered, and a large amount of liquid low molecular weight polymer is by-produced, and the softening point of the hydrocarbon resin is remarkably lowered. It is not preferable.

Examples of the aliphatic diolefin (b) having 4 or 5 carbon atoms include 1,3-butadiene, isoprene, 1,3-pentadiene and cyclopentadiene, and 1,3-pentadiene is especially preferred. Used. When the proportion of the aliphatic diolefin used exceeds 70% by weight, a high-molecular polymer which adversely affects the compatibility with the block copolymer rubber composition (1) is likely to be produced, and the proportion is 20% by weight. If it is less than the above range, a large amount of liquid low molecular weight polymer is by-produced during the cationic polymerization reaction, and the softening point of the resulting hydrocarbon resin is significantly lowered, which is not preferable.

Examples of the aromatic monoolefin (c) having 8 to 10 carbon atoms include styrene, α-methylstyrene, vinyltoluene, isopropenyltoluene, etc. Among them, those having 10 or less carbon atoms are preferable. Awarded. If the usage ratio of such aromatic monoolefin exceeds 40% by weight, the initial adhesive strength is lowered, which is not preferable.
Further, if this ratio is less than 5% by weight, the compatibility with the block copolymer composition (1) decreases, and the melt viscosity in the heat melting process increases, which is not preferable.

Further, other polymerizable components such as dicyclopentadiene, methylcyclopentadiene, indene and methylindene may be contained within a range that does not substantially impair the effects of the present invention.

The hydrocarbon resin (2) used in the present invention can be obtained by cationically polymerizing such a monomer mixture in the presence of a Friedel-Crafts catalyst according to a conventional method. Examples of the catalyst used include Lewis acids, and examples thereof include aluminum halides such as aluminum chloride and aluminum bromide, boron halides, and tin halides. Of these, aluminum halides, especially aluminum chloride, are used. A liquid (aluminum chloride / hydrochloric acid / alkyl-substituted aromatic hydrocarbon) complex can also be used.

As the polymerization solvent, any of aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons and halogenated hydrocarbons can be effectively used, and among them, aromatic hydrocarbons are preferable. This solvent is usually 20 to 1000 parts by weight, preferably 50 to 500 parts by weight, per 100 parts by weight of the monomer.
Used in parts by weight. The polymerization temperature is not particularly limited, but is usually 0 to 120 ° C., preferably 20 to 100.
It is carried out at a temperature of ° C. The pressure of the reaction system is not particularly limited, but is usually atmospheric pressure or higher. The reaction time is not particularly limited, but can usually be changed within the range of several seconds to 12 hours. After the completion of the polymerization, the desired hydrocarbon resin is obtained by treating it according to a conventional method and drying it.

The compounding ratio of the block copolymer rubber composition (1) and the hydrocarbon resin (2) may be varied depending on the required performance of the pressure-sensitive adhesive composition for heat-meltable double-sided tape. 30 to 250 parts by weight, preferably 40 parts by weight of the hydrocarbon resin (2) per 100 parts by weight of the combined rubber composition (1).
˜150 parts by weight are blended.

In the pressure-sensitive adhesive composition for a heat-melting double-sided tape of the present invention, other elastomers or other tackifier resins can be used in combination within a range that does not substantially impair the effects of the present invention. Further, a process oil, a softening agent such as polybutene, an antioxidant, a filler and the like can be added.

The pressure-sensitive adhesive composition for a double-sided hot-melt adhesive tape of the present invention is produced by any method. For example, each compounding component can be put into a blade mixer equipped with a blade having an appropriate shape for kneading and kneaded by heating, and continuously mixed using an extruder type kneader equipped with a uniaxial or biaxial screw. It can also be manufactured. In addition, each compounding component can be stirred and mixed in the presence of a solvent such as toluene to form a pressure-sensitive adhesive solution, and further, a hydrocarbon resin previously emulsified with rubber latex can be stirred and mixed to form a pressure-sensitive adhesive emulsion. . These are adhesive compositions for hot-melt double-sided tape, which are usually applied to a desired substrate using an applicator to produce various adhesive tapes or adhesive label products.

[0045]

EXAMPLES The present invention will be described in more detail with reference to the following examples. In addition, parts and% in the examples, comparative examples and reference examples are based on weight unless otherwise specified. Also,
In this Example, the molecular weight of the polymer is a polystyrene-equivalent weight average molecular weight determined by high performance liquid chromatography using tetrahydrofuran as a carrier.
Furthermore, the composition of the copolymer was determined from the peak area of each copolymer obtained by high performance liquid chromatography.

<Adhesive Properties> An adhesive solution having a non-volatile content of 50% of the block copolymer composition was prepared, and this solution was added to
An adhesive tape was prepared by coating a 5 μm thick polyester film so that the adhesive thickness was 25 μm, and the obtained adhesive tape had an initial adhesive strength, adhesive strength, holding power, and Shear Ad.
Hession Failure Temperature
e (hereinafter referred to as SAFT), the viscosity of the blend was measured. (1) The initial adhesive strength is in accordance with ASTM D-2979,
Using a probe polished with AA No. 400 polishing paper, contact pressure 100 g / cm ² , contact time 1 second, movement time 1 cm
The probe tack was measured at 23 ° C. and 10 ° C. under conditions of 1 / ± 0.2 g / second and a weight of 19.6 ± 0.2 g (unit:
N / cm ² ). (2) According to JIS Z-0237, the adhesive strength was 10 mm in width and 100 mm in length on a stainless steel plate polished with polyethylene film and No. 280 water-resistant abrasive paper.
Adhesive adhesive tape was attached, and it was 200m at 23 ℃.
It was peeled off in the direction of 180 degrees at a speed of m / min and measured (unit: g / cm). (3) In accordance with JIS Z-0237, the holding power is such that an adhesive tape is attached to a stainless steel plate treated in the same manner as described above so that an area of 25 mm × 10 mm is in contact, and a load of 1 kg is applied at 50 ° C. to obtain an adhesive tape. The time required for falling off the stainless steel plate was measured (unit: min). (4) For SAFT, an adhesive tape was attached to a stainless steel plate treated in the same manner as described above so that the area of 25 mm × 10 mm was in contact, and a load of 1 kg was applied to it from 40 ° C. to 0.5.
The temperature was raised at a rate of ° C / min, and the temperature at which the adhesive tape fell off the stainless steel plate was measured (unit: ° C). (5) The compounded viscosity is a pressure-sensitive adhesive composition produced by kneading the block copolymer composition and the hydrocarbon resin at 180 ° C. using a Dartan universal mixing stirrer 5DMV-r type (manufactured by Sanei Seisakusho). Thermocell type viscometer DV-III type (manufactured by Brookfield Engineering Laboratory)
Was used to measure at 180 ° C. (unit: centipoise).

Reference Example 1 Synthesis of Block Copolymer (1) In a 3 liter autoclave under a dry nitrogen atmosphere, 5.7 mmol of n-butyllithium was used as a polymerization initiator in 1500 g of cyclohexane solvent, and 6
Polymerization was carried out by sequentially adding 95 g of styrene and 405 g of isoprene at 0 ° C. for 5 hours, and then performing a coupling reaction using tetramethoxysilane as a coupling agent, as shown in Table 1 (AB) _3. An -X type block copolymer (block copolymer (I)) was produced. (2) In a 3 liter autoclave under a dry nitrogen atmosphere, 5.7 mmol of n-butyllithium was used as a polymerization initiator in 1500 g of a cyclohexane solvent, and 6
Polymerization was performed by sequentially adding 95 g of styrene and 405 g of isoprene at 0 ° C. for 5 hours, and then performing a coupling reaction using dibromobenzene as a coupling agent, and shown in Table 1 (AB) _2. An -X type block copolymer (block copolymer (II)) was produced. (3) In a dry nitrogen atmosphere, in a 3 liter autoclave, using 5.7 mmol of n-butyllithium as a polymerization initiator in 1500 g of cyclohexane solvent,
Polymerization was carried out by sequentially adding 95 g of styrene and 405 g of isoprene at 0 ° C. for 5 hours to produce (AB) type block copolymer (block copolymer (III)) shown in Table 1. Table 1 shows the weight average molecular weights of the obtained block copolymers (I) to (III) and the composition ratio of styrene and isoprene.

[0048]

[Table 1]

Reference Example 2 After charging 100 parts of benzene and 2 parts of aluminum chloride, 100 parts of a monomer mixture having the composition shown in Table 2 was gradually added and copolymerized at 65 ° C. to prepare various hydrocarbon resins (2 ) Was manufactured. The softening point is JIS K-2531.
It was measured according to the ring and ball method specified in. The results are shown in Table 2.

[0050]

[Table 2]

Examples 1 and 2 and Comparative Examples 1 to 3 The block copolymers (I) to (II prepared in Reference Example 1 were used.
I) was used to prepare the block copolymer composition (1) in the weight ratio shown in Table 3, and these block copolymer composition (1) and the hydrocarbon resin (2) produced in Reference Example 2 were used. According to the formulation shown in Table 4, each component was kneaded with a Dalton kneader to produce a pressure-sensitive adhesive composition, and the composition was dissolved in toluene (nonvolatile content concentration 50%), and this solution was 25 μm.
An adhesive tape was prepared by applying a paste having a thickness of 25 μm on a thick polyester film. The results are summarized in Table 2
Shown in.

[0052]

[Table 3]

[0053]

[Table 4]

From the results shown in Table 4, the pressure-sensitive adhesive tape using the pressure-sensitive adhesive composition for hot-melt double-sided tape of the present invention was compared with that using the conventional aliphatic hydrocarbon resin as a pressure-sensitive adhesive.
It can be seen that it has a low melt viscosity and is excellent in the balance of the initial adhesive force, the adhesive force and the holding force.

[0055]

As described above, according to the present invention, a pressure-sensitive adhesive composition for a double-sided hot-melt tape having a low melt viscosity and an excellent balance of initial adhesive strength, adhesive strength and holding strength can be obtained.

Claims (1)

[Claims] 1. A block copolymer (I) represented by formula (AB) _n X, a block copolymer (II) represented by formula (AB) ₂ Y, and And a block copolymer (III) represented by the formula (AB), (wherein
n = 3 or 4, A is a polymer block of an aromatic vinyl monomer, B is a polymer block of a conjugated diene monomer,
X is a residue of a trifunctional or tetrafunctional coupling agent,
Y represents the residue of a bifunctional or tetrafunctional coupling agent. ) The weights of (I), (II) and (III) are
(I) / (II) = 5/95 to 95/5 and ((I)
+ (II)) / (III) = 45/55 to 95/5, in the block copolymer composition (1), an aliphatic monoolefin (a) 5 having 4 to 8 carbon atoms is added. ~
A single amount containing 60% by weight, 20 to 70% by weight of an aliphatic diolefin (b) having 4 or 5 carbon atoms, and 5 to 40% by weight of an aromatic monoolefin (c) having 8 to 10 carbon atoms. A pressure-sensitive adhesive composition for a hot-melt double-sided tape, comprising a hydrocarbon resin (2) obtained by cationically polymerizing a body mixture in the presence of a Friedel-Crafts catalyst.