阅读说明：本技术 嵌段共聚物、聚合物组合物、粘着粘结剂用组合物、粘着粘结剂组合物以及偶联剂 (Block copolymer, polymer composition, adhesive composition, and coupling agent ) 是由 谷口直树 龟田一平 山田将士 山本整 于 2019-01-28 设计创作，主要内容包括：一种嵌段共聚物,其由下述通式(1)或(2)所表示,包含以乙烯基芳香族单体单元为主体的聚合物嵌段(A)和以共轭二烯单体单元为主体的聚合物嵌段(B)。(通式(1)、(2)中,曲线部为碳原子数1～20的饱和或不饱和的烃基,可以无取代,也可以带有取代基。X为1族元素。“polymer”为聚合物。)<Image he="253" wi="700" file="DDA0002584973700000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(A block copolymer represented by the following general formula (1) or (2) and comprising a polymer block (A) mainly composed of vinyl aromatic monomer units and a polymer block (B) mainly composed of conjugated diene monomer units. (in the general formulas (1) and (2), the curved line part is saturated or unsaturated with 1-20 carbon atomsThe saturated hydrocarbon group may be unsubstituted or substituted. X is a group 1 element. A "polymer" is a polymer. ))

1. A block copolymer represented by the following general formula (1) or (2) and comprising a polymer block (A) mainly composed of vinyl aromatic monomer units and a polymer block (B) mainly composed of conjugated diene monomer units,

[ solution 1]

[ solution 2]

In the general formulas (1) and (2), the curve part is a saturated or unsaturated alkyl group with 1-20 carbon atoms, and is unsubstituted or provided with a substituent; x is a group 1 element; a "polymer" is a polymer.

2. A block copolymer represented by the following general formula (A1) or (A2) and comprising a polymer block (A) mainly composed of vinyl aromatic monomer units and a polymer block (B) mainly composed of conjugated diene monomer units,

[ solution 3]

[ solution 4]

In the general formulas (A1) and (A2), the curve part is a saturated or unsaturated alkyl group with 1-20 carbon atoms, and is unsubstituted or provided with a substituent; x is a group 1 element; a "polymer" is a polymer.

3. The block copolymer according to claim 1 or 2, which is a block copolymer represented by the following formula (a) and/or (B) comprising a polymer block (A) mainly comprising vinyl aromatic monomer units and a polymer block (B) mainly comprising conjugated diene monomer units,

(a) (A-B)_n-Y'

(b) (B-A-B)_n-Y'

in the formulas (a) and (b), n represents an integer of 1-4, Y' represents a coupling agent residue obtained by coupling a block copolymer with a coupling agent having a structure represented by the following formula (Y1) or (Y2),

[ solution 5]

[ solution 6]

In the formulas (Y1) and (Y2), the curve part is a saturated or unsaturated alkyl group with 1-20 carbon atoms, and is unsubstituted or provided with a substituent; z is a functional group which can be detached through a coupling reaction; in addition, X is a group 1 element.

4. A polymer composition comprising the block copolymer according to any one of claims 1 to 3.

5. The polymer composition according to claim 4, further comprising a polymer represented by the following general formula (3) and/or a polymer represented by the following general formula (4),

[ solution 7]

[ solution 8]

In the formulas (3) and (4), the curve part is a saturated or unsaturated alkyl group with 1-20 carbon atoms, and is unsubstituted or provided with a substituent; x is a group 1 element; a "polymer" is a polymer.

6. The polymer composition according to claim 4 or 5, wherein the content of the vinyl aromatic monomer unit in the polymer composition is 5 to 60% by mass.

7. The polymer composition according to any one of claims 4 to 6, wherein,

the composition comprises at least one block copolymer represented by the general formula (1) as a branched chain body or a block copolymer represented by n in the general formula (a) or (b) as a branched chain body, wherein n represents 1,

the number average molecular weight of the block copolymer as a branched polymer is 150,000 or less.

8. The polymer composition according to claim 7, wherein the content of the block copolymer as a branched polymer is 10 to 90% by mass.

9. The polymer composition according to any one of claims 4 to 8, wherein a 25 mass% toluene solution of the polymer composition has a viscosity of 250 mPas or less at 25 ℃.

10. The polymer composition according to any one of claims 4 to 9, wherein a 15 mass% toluene solution of the polymer composition has a viscosity of 40 mPa-s or less at 25 ℃.

11. A composition for an adhesive binder comprising the polymer composition according to any one of claims 4 to 10.

12. The adhesive composition according to claim 11, which comprises the polymer composition C1 according to any one of claims 4 to 10, and a polymer other than the polymer composition C1 and/or the polymer composition C2.

13. An adhesive binder composition comprising:

the adhesive composition according to claim 11 or 12, wherein the adhesive composition comprises 100 parts by mass of,

50 to 400 parts by mass of a tackifier, and

10 to 150 parts by mass of a softener.

14. A coupling agent which is reactive with a polymer comprising at least conjugated diene monomer units and is represented by the following general formula (Y1) or (Y2),

[ solution 9]

[ solution 10]

In the general formulas (Y1) and (Y2), the curve part is a saturated or unsaturated alkyl group with 1-20 carbon atoms, and is unsubstituted or provided with a substituent; z is a functional group which can be detached through a coupling reaction; in addition, X is a group 1 element.

Technical Field

The present invention relates to a block copolymer, a polymer composition, an adhesive composition, and a coupling agent.

Background

In the application to sheets, films and the like, various attempts have been made to provide sufficient strength, improve processability, or reduce product cost by using a composition or a laminate of a plurality of components in which other components are mixed with a polymer substance.

In addition, in the case of an adhesive, an attempt to increase strength by adding a tackifier to a polymer substance has been made, and in the case of an application to modify asphalt, an attempt to increase strength by adding a polymer substance to asphalt has been made.

Materials used for these applications generally require a compromise between low viscosity and high mechanical strength.

In recent years, vinyl aromatic monomer-conjugated diene monomer block copolymers (for example, SBS: styrene-butadiene-styrene block copolymer, SIS: styrene-isoprene-styrene block copolymer) have been widely used as base polymers for solution-type and hot-melt-type adhesives or adhesives.

For example, patent document 1 discloses a polymer composition for adhesives or stickers using SBS.

However, polymer compositions for adhesives or stickers using SBS or SIS have a problem that the balance between processability and adhesive properties such as adhesive force is insufficient, and melt viscosity is increased and processability is deteriorated when attempting to obtain high adhesive properties.

As a technique for improving the balance between the processability and the adhesive property, patent document 2 discloses a polymer composition for an adhesive containing a triblock copolymer and a diblock copolymer.

Patent document 3 discloses a polymer composition for an adhesive binder containing 2 or more block copolymer compositions.

Disclosure of Invention

Problems to be solved by the invention

However, the polymer compositions disclosed in the prior art are insufficient in tensile physical properties, and the polymer compositions disclosed in patent documents 1 to 3 are insufficient in the effect of improving the balance between processability and adhesive properties, and therefore further improvement is desired.

In view of the problems of the prior art, an object of the present invention is to provide a block copolymer capable of providing a polymer composition having excellent tensile properties and an excellent balance between low viscosity and adhesive properties, which are processability, a polymer composition containing the block copolymer, and an adhesive composition containing the polymer composition.

Means for solving the problems

The present inventors have made extensive studies to solve the above problems of the prior art, and as a result, have found that the above problems can be effectively solved by a block copolymer having a specific structure, and have completed the present invention.

Namely, the present invention is as follows.

[1]

A block copolymer represented by the following general formula (1) or (2) and comprising a polymer block (A) mainly composed of vinyl aromatic monomer units and a polymer block (B) mainly composed of conjugated diene monomer units.

[ solution 1]

[ solution 2]

(in the general formulae (1) and (2), the curved portion is a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, which may be unsubstituted or substituted, and X is a group 1 element, "polymer" is a polymer.)

[2]

A block copolymer represented by the following general formula (A1) or (A2) and comprising a polymer block (A) mainly composed of vinyl aromatic monomer units and a polymer block (B) mainly composed of conjugated diene monomer units.

[ solution 3]

[ solution 4]

(in the general formulae (A1) and (A2), the curved portion is a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, which may be unsubstituted or substituted, and X is a group 1 element

[3]

The block copolymer represented by the above [1] or [2], which is a block copolymer represented by the following formula (a) and/or (B), comprising a polymer block (A) mainly composed of vinyl aromatic monomer units and a polymer block (B) mainly composed of conjugated diene monomer units.

(a)(A-B)_n-Y′

(b)(B-A-B)_n-Y′

(in the formulae (a) and (b), n represents an integer of 1 to 4, and Y' represents a coupling agent residue obtained by coupling a block copolymer with a coupling agent having a structure represented by the following formula (Y1) or (Y2))

[ solution 5]

[ solution 6]

(in the formulae (Y1) and (Y2), the curved portion is a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, which may be unsubstituted or substituted; Z is a functional group which can be eliminated by a coupling reaction; and X is a group 1 element.)

[4]

A polymer composition comprising the block copolymer according to any one of the above [1] to [3 ].

[5]

The polymer composition as described in the above [4], which further comprises a polymer represented by the following general formula (3) and/or a polymer represented by the following general formula (4).

[ solution 7]

[ solution 8]

(in the formulae (3) and (4), the curved portion is a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, which may be unsubstituted or substituted, and X is a group 1 element, "polymer" is a polymer.)

[6]

The polymer composition according to the above [4] or [5], wherein the content of the vinyl aromatic monomer unit in the polymer composition is 5 to 60% by mass.

[7]

The polymer composition according to any one of the above [4] to [6], wherein,

the composition comprises at least one block copolymer represented by the general formula (1) as a branched chain body or a block copolymer represented by the general formula (a) or (b) wherein n represents 1 as a branched chain body,

the number average molecular weight of the block copolymer as a branched chain is 150,000 or less.

[8]

The polymer composition according to [7], wherein the content of the block copolymer as a branched polymer is 10 to 90% by mass.

[9]

The polymer composition according to any one of the above [4] to [8], wherein a 25 mass% toluene solution of the polymer composition has a viscosity of 250 mPas or less at 25 ℃.

[10]

The polymer composition according to any one of the above [4] to [9], wherein a 15 mass% toluene solution of the polymer composition has a viscosity of 40 mPas or less at 25 ℃.

[11]

An adhesive composition comprising the polymer composition according to any one of the above [4] to [10 ].

[12]

The adhesive composition according to [11], which comprises the polymer composition C1 according to any one of [4] to [10], and a polymer other than the polymer composition C1 and/or the polymer composition C2.

[13]

An adhesive binder composition comprising:

100 parts by mass of the adhesive composition according to [11] or [12],

50 to 400 parts by mass of a tackifier, and

10 to 150 parts by mass of a softener.

[14]

A coupling agent which is reactive with a polymer containing at least conjugated diene monomer units and is represented by the following general formula (Y1) or (Y2).

[ solution 9]

[ solution 10]

(in the general formulae (Y1) and (Y2), the curved portion is a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, which may be unsubstituted or substituted; Z is a functional group which can be eliminated by a coupling reaction; and X is a group 1 element.)

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention provides a block copolymer for obtaining a polymer composition having excellent tensile properties and an adhesive composition having excellent processability, i.e., excellent balance between low viscosity and adhesive properties, a polymer composition comprising the block copolymer, an adhesive composition containing the polymer composition, and an adhesive composition.

Detailed Description

The following describes in detail a specific embodiment of the present invention (hereinafter referred to as "the present embodiment"). The following embodiments are illustrative of the present invention, and are not intended to limit the present invention to the following. The present invention can be implemented by being variously modified within the scope of the gist thereof.

[ Block copolymer ]

(Block copolymer of the first embodiment)

The block copolymer of the first embodiment among the block copolymers of the present embodiment is a block copolymer comprising a polymer block (a) mainly composed of a vinyl aromatic monomer unit and a polymer block (B) mainly composed of a conjugated diene monomer unit, and is represented by the following general formula (1) or (2).

[ solution 11]

[ solution 12]

(Block copolymer of the second embodiment)

The block copolymer of the second embodiment among the block copolymers of the present embodiment is a block copolymer comprising a polymer block (a) mainly composed of vinyl aromatic monomer units and a polymer block (B) mainly composed of conjugated diene monomer units, and is represented by the following general formula (a1) or (a 2).

[ solution 13]

[ solution 14]

In the general formulae (1), (2), (A1) and (A2), the curved line part represents a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and may be unsubstituted or substituted. In addition, X is a group 1 element.

In the above general formulae (1), (2), (A1) and (A2), "polymer" represents a polymer moiety. The production method is not particularly limited, and a production method in which a structure represented by the above general formulae (1), (2), (a1), and (a2) is formed by polymerizing a "polymer" and reacting a coupling agent with a polymerization active end is one of practically preferable production methods.

By including the polymer block (a) mainly composed of a vinyl aromatic monomer unit, the mechanical properties (tensile properties) of the polymer composition of the present embodiment are improved as compared with the case where the polymer block (a) is not included, the holding power of the adhesive composition using the block copolymer of the present embodiment is improved, and the balance between the holding power and the melt viscosity is improved.

The "carbon number of 1 to 20" in the curve represents the length of the main chain of a saturated hydrocarbon or an unsaturated hydrocarbon. If the number of carbon atoms is too large, the coupling efficiency is lowered with respect to the amount of the coupling agent added, which is not preferable in terms of cost.

When the curved portion has a substituent, the substituent may be singular or plural, and the number of carbon atoms of the substituent is preferably 1 to 20. When the number of carbon atoms of the substituent is more than 20, the substituent is too large, steric hindrance increases, and the polymer and the coupling agent are difficult to associate with each other, and the coupling reaction tends to be slow.

When the substituent is a saturated or unsaturated hydrocarbon group, it may be an independent group or may form a ring structure. When the substituent is a functional group, there may be cases where it preferably has an interaction with a carbonyl group in a molecule by a hydrogen bond, and therefore the substituent may be appropriately selected in consideration of the interaction with a carboxyl group and the like. Preferable examples of the substituent include a hydroxyl group, a carboxyl group, an epoxy group, an amino group, a silanol group and an alkoxysilyl group.

Since the block copolymer having the structure represented by the general formulae (1), (2), (a1), and (a2) contains in the molecule a functional group capable of forming a complementary association state by hydrogen bonding, it is believed that the block copolymer effectively forms hydrogen bonding with molecules other than the block copolymer itself having the structure represented by the general formulae (1), (2), (a1), and (a2) at room temperature, and is easily expressed as a molecule having an apparent molecular weight. Therefore, the tensile properties tend to be improved as compared with the case where such a structure is not included.

For the same reason, the holding power in the adhesive composition using the block copolymer of the present embodiment tends to be improved. On the other hand, since hydrogen bonds are broken at high temperatures, they tend to be relatively small molecules and the melt viscosity tends to be lowered at the time of melt flow rate measurement or under high temperature conditions under which the adhesive composition can melt, as compared with room temperature conditions.

For the above reasons, the block copolymer of the present embodiment can be preferably used for applications such as sheets and films which require both high tensile physical properties and high melt flow rate, and for applications of adhesive compositions which require both high holding power and low viscosity after production of the adhesive compositions.

The block copolymers of the general formulae (1) and (a1) are preferably block copolymers represented by the following general formula (I), and the block copolymers of the general formulae (2) and (a2) are preferably block copolymers represented by the following general formula (II). By adopting these structures, hydrogen bonds tend to be formed more efficiently.

[ solution 15]

[ solution 16]

In the general formulae (I) and (II), the curved line part represents a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and may be unsubstituted or substituted. In addition, X is a group 1 element.

In the above general formulae (I) and (II), "polymer" represents a polymer moiety.

From the viewpoint of ease of production, the block copolymer of the general formulae (1) and (a1) is preferably a block copolymer represented by the following general formula (i), and similarly, the block copolymer of the general formulae (2) and (a2) is preferably a block copolymer represented by the following general formula (ii).

[ solution 17]

[ solution 18]

In the formulae (i) and (ii), R₁、R₂Is hydrogen or C1-20 unsubstituted or substituted saturated or unsaturated alkyl, R₁And R₂May be independent of each other or may form a ring structure. In addition, X is a group 1 element.

In the above general formulae (i) and (ii), "polymer" represents a polymer moiety.

As described above, the block copolymer of the present embodiment is a block copolymer including the polymer block (a) mainly composed of vinyl aromatic monomer units and the polymer block (B) mainly composed of conjugated diene monomer units.

The "conjugated diene monomer unit" represents a structure resulting from polymerization of 1 conjugated diene compound.

The conjugated diene compound is not particularly limited as long as it is a diene having a conjugated double bond, and examples thereof include 1, 3-butadiene, 2-methyl-1, 3-butadiene (isoprene), 2, 3-dimethyl-1, 3-butadiene, 1, 3-pentadiene, 1, 3-hexadiene, and the like.

Among these, 1, 3-butadiene and isoprene are preferable as the conjugated diene compound. Further, the use of 1, 3-butadiene is more preferable because it tends to form an adhesive binder excellent in heat aging resistance and light resistance.

The conjugated diene compound may be used alone or in combination of two or more.

The "vinyl aromatic monomer unit" refers to a structure obtained by polymerizing 1 vinyl aromatic hydrocarbon compound.

Examples of the vinyl aromatic hydrocarbon compound include, but are not limited to, alkylstyrenes such as styrene, α -methylstyrene, p-methylstyrene and p-tert-butylstyrene; alkoxystyrenes such as p-methoxystyrene; vinyl naphthalene, and the like.

Among these, styrene is preferable as the vinyl aromatic hydrocarbon.

One kind of the vinyl aromatic hydrocarbon compound may be used alone, or two or more kinds may be used in combination.

The "polymer block (a) mainly composed of vinyl aromatic monomer units" means a polymer block in which the proportion of vinyl aromatic monomer units to the whole polymer block (a) is 50% by mass or more, preferably 70% by mass or more, more preferably 85% by mass or more, and still more preferably 95% by mass or more.

The "polymer block (B) mainly composed of conjugated diene monomer units" means a polymer block in which the proportion of conjugated diene monomer units to the entire polymer block (B) is more than 50% by mass, preferably 70% by mass or more, more preferably 85% by mass or more, and still more preferably 95% by mass or more.

The block rate of the vinyl aromatic hydrocarbon introduced into the block copolymer can be determined from the following formula using a vinyl aromatic hydrocarbon polymer block component obtained by a method (method described in i.m. koltoff et al, j.polym. sci.1, 429 (1946)) in which a block copolymer is oxidatively decomposed with tert-butyl hydroperoxide using osmium tetroxide as a catalyst (a method described in i.m. koltoff et al, j.polym. sci.1, 429 (1946)).

Block ratio (mass%) of vinyl aromatic hydrocarbon

(mass of vinyl aromatic hydrocarbon polymer block in block copolymer/mass of all vinyl aromatic hydrocarbons in block copolymer) × 100

Another embodiment of the block copolymer of the present embodiment is a block copolymer represented by the following formula (a) and/or (B) and including a polymer block (a) mainly composed of a vinyl aromatic monomer unit and a polymer block (B) mainly composed of a conjugated diene monomer unit.

(a)(A-B)_n-Y′

(b)(B-A-B)_n-Y′

(in the formulae (a) and (b), n represents an integer of 1 to 4, and Y' represents a coupling agent residue obtained by coupling a block copolymer with a coupling agent having a structure represented by the following formula (Y1) or (Y2))

[ solution 19]

[ solution 20]

(in the formulae (Y1) and (Y2), the curved portion is a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, which may be unsubstituted or substituted; Z is a functional group which can be eliminated by a coupling reaction; and X is a group 1 element.)

The compound of the general formula (Y1) is preferably a compound represented by the following general formula (Y-I), and the compound of the general formula (Y2) is preferably a compound represented by the following general formula (Y-II).

[ solution 21]

[ solution 22]

(in the formulae (Y-I) and (Y-II), R₁、R₂Is hydrogen or C1-20 unsubstituted or substituted saturated or unsaturated alkyl, R₁And R₂May be independent of each other or may form a ring structure. Z is a functional group which can be eliminated by a coupling reaction. In addition, X is a group 1 element. )

When a molecule having a coupling agent residue Y 'is obtained by coupling a block copolymer using a modifier (or a coupling agent) having a structure represented by the above formula (Y1) or (Y2), Y' contains a functional group in the molecule that can form a complementary association state by hydrogen bonding, as described in the above general formulae (1), (2), (a1), and (a 2). Therefore, the block copolymer of the present embodiment can improve the tensile properties, and the adhesive composition using the block copolymer of the present embodiment tends to have an improved holding power and an improved balance between the holding power and the melt viscosity.

[ Polymer composition ]

When the block copolymer of the present embodiment is used for an application of an adhesive composition, it is preferable to prepare a polymer composition further containing a component having another structure.

For example, when a polymer composition containing the block copolymer represented by the general formula (1) and the block copolymer represented by the general formula (2) or a polymer composition containing the block copolymer represented by the general formula (a1) and the block copolymer represented by the general formula (a2) is prepared, the mechanical properties are further improved, the holding power when preparing an adhesive composition is improved, and the balance between the holding power and the melt viscosity tends to be improved.

The polymer composition of the present embodiment preferably contains a block copolymer represented by the general formula (1) and/or (2) or the general formula (a1) and/or (a2) and further contains a polymer represented by the general formula (3) and/or the general formula (4).

[ solution 23]

[ solution 24]

(in the formulas (3) and (4), the curved line part is a saturated or unsaturated alkyl group with 1-20 carbon atoms, which may be unsubstituted or substituted, and X is a group 1 element.

In the formulas (3) and (4), "polymer" is a polymer. )

The polymer of the general formula (3) is preferably a polymer represented by the following general formula (III), and the polymer of the general formula (4) is preferably a polymer represented by the following general formula (IV).

[ solution 25]

[ solution 26]

In the formulae (III) and (IV), the curved portion is a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and may be unsubstituted or substituted. In addition, X is a group 1 element.

The polymer of the general formula (3) is preferably a polymer represented by the following general formula (iii), and the polymer of the general formula (4) is preferably a polymer represented by the following general formula (iv).

[ solution 27]

[ solution 28]

In the general formulae (iii) and (iv), R₁、R₂Is hydrogen or C1-20 unsubstituted or substituted saturated or unsaturated alkyl, R₁And R₂May be independent of each other or may form a ring structure. In addition, X is a group 1 element.

The polymer represented by the general formula (3) and/or the general formula (4) contains a functional group that forms a hydrogen bond weaker than the block copolymer represented by the general formula (1) and/or the general formula (2) or the general formula (a1) and/or the general formula (a 2). These polymers alone cannot greatly improve the mechanical strength at room temperature and the holding power when they are used as an adhesive composition, but they tend to have an effect of assisting the improvement of the mechanical strength and the holding power when they are used as an adhesive composition by compounding them with the block copolymer represented by the general formula (1) and/or the general formula (2) or the general formula (a1) and/or the general formula (a 2). Further, since these polymers have a larger number of branches than the block copolymers represented by the general formulae (1) and (a1), the effects of improving mechanical strength and holding power when producing an adhesive composition are easily exhibited, and the balance between melt viscosity and mechanical strength is easily adjusted.

When the block copolymer is coupled using the coupling agent represented by the formula (Y1) or (Y2), the polymer represented by the formula (3) and/or the formula (4) is produced via or simultaneously with the block copolymer represented by the formula (1) and/or the formula (2) or the formula (a1) and/or the formula (a2), and therefore, compounding is also preferable in terms of ease of production.

R in the above general formulae (I) to (iv), (Y-I) and (Y-II)₁、R₂Is hydrogen or a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms and having no substituent or a substituent.

Here, when the number of carbon atoms of the saturated or unsaturated hydrocarbon group is 21 or more, the coupling reaction is slow, and therefore, it is not preferable from the viewpoint of productivity. From the viewpoint of productivity, the number of carbon atoms is preferably 20 or less, more preferably 15 or less, and still more preferably 10 or less.

If the number of carbon atoms is too small, it is difficult to control the number of branches (the number of reactions of the copolymer molecules with the coupling agent). That is, the number of carbon atoms is preferably 1 or more, more preferably 3 or more, and further preferably 5 or more, from the viewpoint of controlling the number of branches of the target block copolymer.

As described above, since the block copolymer of the present embodiment contains a functional group in a molecule that can form a complementary association state by hydrogen bonding, the block copolymer of the present embodiment effectively forms hydrogen bonding with molecules other than the block copolymer itself of the present embodiment at room temperature, and the hydrogen bonding is considered to affect tensile strength, holding power when used for an adhesive binder, and the like. Therefore, the block copolymer of the present embodiment has no limitation on the structure of the other portion as long as it has the above structure and satisfies the limitation of the number of carbon atoms from the viewpoint of the production process as described above. Accordingly, R in the above general formulae (I) to (iv), (Y-I) and (Y-II)₁、R₂May be a saturated hydrocarbon or an unsaturated hydrocarbon, and may have a substituentThe substituent may be unsubstituted. In the case of having a substituent, there may be a case where it preferably has an interaction with the above-mentioned hydrogen bond, and therefore it may be appropriately selected in consideration of an interaction with a carboxyl group or the like. Preferable examples of the substituent include a hydroxyl group, a carboxyl group, an epoxy group, an amino group, a silanol group and an alkoxysilyl group.

In addition, R in the formulae (I), (II), (iii), (iv), (Y-I) and (Y-II)₁And R₂May have different structures or the same structure, R₁And R₂Ring structures connected in a ring shape may be formed.

R₁And R₂In the case of different structures, one may be preferably used as long as the number of carbon atoms is within the above range, and in this case, the other may be preferably used as hydrogen. The ring of the ring structure may be an alicyclic ring or an aromatic ring.

X in the above general formulae (1) to (4), (a1), (a2), and (Y2) is a group 1 element.

Examples of the group 1 element include hydrogen, lithium, sodium, potassium, rubidium, and the like, and X is preferably hydrogen or lithium in terms of effective formation of hydrogen bonds in the polymer of the present embodiment.

In the polymer composition of the present embodiment, the content of the vinyl aromatic monomer unit in the polymer composition is preferably 5 to 60% by mass.

When the content of the vinyl aromatic monomer unit is in the above range, the balance between the mechanical strength and the elongation tends to be improved. In addition, the content of the vinyl aromatic monomer unit is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, further preferably 25% by mass or more, further preferably 30% by mass or more, and particularly preferably 40% by mass or more, from the viewpoint of improving the holding power when the pressure-sensitive adhesive composition is produced.

In addition, the content of the vinyl aromatic monomer unit is preferably 60% by mass or less, more preferably 50% by mass or less, further preferably 45% by mass or less, further preferably 40% by mass or less, further preferably 30% by mass or less, and particularly preferably 25% by mass or less, from the viewpoint of lowering the melt viscosity when the pressure-sensitive adhesive composition is produced.

The content of the vinyl aromatic monomer unit can be suitably designed in accordance with the balance between the holding power and the melt viscosity required for preparing the adhesive composition. When the content of the vinyl aromatic monomer unit is small, the melt viscosity tends to decrease in a temperature range of about 100 ℃.

The content of the vinyl aromatic monomer unit in the polymer composition can be controlled by adjusting the amount of the vinyl aromatic monomer added in the polymerization reaction of the block copolymer of the present embodiment.

The content of the vinyl aromatic monomer unit in the polymer composition can be measured by the method described in the examples described later.

The polymer composition of the present embodiment preferably contains at least one of the block copolymers represented by the general formulae (1) and (a1) as a branched chain, or the block copolymers represented by the general formulae (a) and (b) as a branched chain in which n represents 1, and the number average molecular weight of the branched chain is 150,000 or less.

When the number average molecular weight of the block copolymer as a branched structure is low, the melt viscosity of the adhesive composition tends to be low. Therefore, the number average molecular weight of the block copolymer as a branched structure is preferably 150,000 or less, more preferably 120,000 or less, further preferably 70,000 or less, further more preferably 60,000 or less, and further more preferably 50,000 or less.

On the other hand, if the number average molecular weight of the block copolymer as a branched polymer is too low, the finishing property at the time of producing the polymer composition of the present embodiment tends to be deteriorated, or the holding power at the time of producing the adhesive composition tends to be lowered. More specifically, although it is effective to set the number average molecular weight of the block copolymer as a branched structure low in order to reduce the viscosity of the adhesive composition, if the number average molecular weight is too low, the variation of the polymer composition of the present embodiment increases, and molding into pellets tends to be difficult. Therefore, the number average molecular weight of the block copolymer as a branched structure is preferably 30,000 or more, more preferably 40,000 or more, and further preferably 50,000 or more.

The number average molecular weight of the block copolymer suitable as a branched polymer can be designed in accordance with the balance between the adhesive property and the melt viscosity required for preparing an adhesive composition.

The number average molecular weight of the block copolymer as a branched structure contained in the polymer composition of the present embodiment can be controlled by adjusting polymerization conditions such as the amount of monomer added, polymerization temperature, and polymerization time in polymerizing the block copolymer.

When the content of the block copolymer as a branched polymer in the polymer composition of the present embodiment is large, the melt viscosity tends to be lowered or the adhesive force tends to be increased when the adhesive composition is prepared. From this viewpoint, the content of the block copolymer as a branched polymer is preferably 10% by mass or more, more preferably 20% by mass or more, further preferably 40% by mass or more, and further preferably 60% by mass or more, based on the whole polymer composition.

When the content of the block copolymer as a branched polymer is small, the holding power when the adhesive composition is produced tends to be improved. Therefore, the content of the block copolymer as a branched polymer is preferably 90% by mass or less, more preferably 80% by mass or less, further preferably 70% by mass or less, and further more preferably 60% by mass or less, based on the entire polymer composition.

In addition, in applications requiring high mechanical properties such as sheet and film applications, the lower the content of the block copolymer as a branched chain body, the more the mechanical properties tend to be improved. That is, it is preferable that the content of the block copolymer as a diblock copolymer is high, and by containing a block copolymer as a triblock or higher branched chain, it is possible to improve mechanical properties even when the content of the block copolymer as a branched chain is reduced. In such applications, the content of the block copolymer as a diblock is preferably high in the general formula (2) or the general formulae (a) and (b) in which n represents 2, and the mass ratio of the content of the diblock to the content of the polymer as a monoblock (the amount of diblock/the amount of monoblock) is preferably 0.3 or more, more preferably 0.5 or more, further preferably 1 or more, and further preferably 2 or more.

In such applications, a mode in which the block copolymer as a branched structure is not included at all can also be preferably used.

In the case of preparing an adhesive composition, the content of the branched chain can be appropriately adjusted according to the balance between the required adhesive property and melt viscosity.

The viscosity of a 25 mass% toluene solution of the polymer composition of the present embodiment at 25 ℃ is preferably 250mPa · s or less, more preferably 220mPa · s or less, further preferably 200mPa · s or less, further preferably 180mPa · s or less, and further preferably 150mPa · s or less.

When the viscosity of the 25 mass% toluene solution of the polymer composition of the present embodiment is in the range of 250mPa · s or less at 25 ℃, an adhesive composition having excellent adhesiveness, solubility, coatability, and discharge stability tends to be obtained.

The 25 mass% toluene solution of the polymer composition of the present embodiment has a viscosity of preferably 50mPa · s or more, more preferably 80mPa · s or more, and still more preferably 120mPa · s or more at 25 ℃.

When the viscosity of the 25 mass% toluene solution of the polymer composition of the present embodiment is in the range of 50mPa · s or more at 25 ℃, an adhesive binder composition having an excellent balance between the adhesive property and the melt viscosity tends to be obtained.

The viscosity of a 25 mass% toluene solution of the polymer composition at 25 ℃ can be controlled within the above numerical range by adjusting the number average molecular weight of the polymer, the content of a branched chain body, the content of a vinyl aromatic hydrocarbon, and the like.

The viscosity of a 15 mass% toluene solution of the polymer composition of the present embodiment at 25 ℃ is preferably 40mPa · s or less, more preferably 30mPa · s or less, and still more preferably 20mPa · s or less.

By setting the viscosity of the 15 mass% toluene solution of the polymer composition of the present embodiment to a range of 40mPa · s or less at 25 ℃, an adhesive binder composition having excellent adhesive properties, solubility, coatability, and discharge stability tends to be obtained.

The viscosity of a 15 mass% toluene solution of the polymer composition of the present embodiment at 25 ℃ is preferably 10mPa · s or more, and more preferably 20mPa · s or more.

When the viscosity of the 15 mass% toluene solution of the polymer composition of the present embodiment is in the range of 10mPa · s or more at 25 ℃, an adhesive binder composition having an excellent balance between the adhesive property and the melt viscosity tends to be obtained.

[ composition for adhesive Binder ]

The adhesive composition of the present embodiment includes the polymer composition of the present embodiment.

This provides an adhesive composition having an excellent balance between melt viscosity, i.e., processability, and adhesive properties.

The polymer composition of the present embodiment is excellent in the balance between the adhesive property and the melt viscosity, and therefore can be preferably used as a material for an adhesive composition, but in order to adjust the balance between the adhesive property and the melt viscosity, it is preferable to prepare the adhesive composition of the present embodiment as a polymer composition to which a polymer other than the block copolymer of the present embodiment is added.

That is, the polymer composition C1 of the present embodiment contains the block copolymer represented by the above general formula (1), (2), (a1), or (a2), and is obtained in the production process as a mixture with the polymer represented by the above general formula (3) and/or (4) or the polymer before coupling, the four-branched chain body, or the like represented by the above general formulae (1) to (4) as the "polymer", and depending on the use of the polymer, it may be preferable to use a polymer and/or a polymer composition mixed with a polymer and/or a polymer composition that enhances and/or supplements the performance of the polymer and has a structure different from that of the polymer composition C1 of the present embodiment.

Examples of the polymer having a structure different from that of the polymer composition C1 and/or the polymer composition C2 of the present embodiment include a coupled polymer produced using a coupling agent having a structure different from those of the formulae (Y1) and (Y2), and a linear polymer having a structure different from that of the "polymer" in the formulae (1) to (4).

In addition, in the case where the polymer and/or the polymer composition C2 is produced in the form of a mixture with the polymer before coupling, it may be mixed with the polymer composition C1 or a composition containing it in the state of a mixture containing the polymer and/or the polymer composition C2 in the preparation of an adhesive binder composition.

The polymer other than the polymer composition C1 and/or the polymer composition C2 are not particularly limited, but a styrene-butadiene block copolymer, a styrene-isoprene block copolymer, or a composition containing them is preferable.

In particular, when a block copolymer having a high melt viscosity is contained, the melt viscosity of the pressure-sensitive adhesive composition obtained using the polymer composition of the present embodiment is increased, but an effect of improving the holding power can be provided, and this is preferable.

The mixing ratio of the polymer composition C1 and the polymer and/or the polymer composition C2 is not particularly limited, and may be appropriately set according to the purpose and the performance of each polymer, and (mass of C1)/((mass of C1) + (mass of C2)) is preferably 0.1 to 0.9, from the viewpoint of clarifying the effect of enhancing and/or supplementing the functions by mixing.

An example of the preparation concept of the adhesive composition comprising polymer composition C1 and polymer and/or polymer composition C2 is shown below.

Although it depends on the structure of the "polymer" moiety in the above general formulae (1) to (4), the structure of the curved portion, and R in the above formulas (i), (ii), (iii) and (iv)₁And/or R₂However, the polymer composition C1 of the present embodiment tends to have a very high holding power at 40 ℃ and a not very high holding power at 60 ℃.

When it is desired to improve the holding power at 60 ℃ in addition to the holding power at 40 ℃, the composition for an adhesive of the present embodiment tends to obtain desired characteristics by mixing a polymer having a structure different from that of the polymer composition C1 and/or the polymer composition C2. From this viewpoint, preferable examples of the polymer and/or the polymer composition C2 to be added include a styrene-butadiene block copolymer or a styrene-isoprene block copolymer having a larger content of vinyl aromatic monomer units than in the polymer composition C1, a styrene-butadiene block copolymer or a styrene-isoprene block copolymer having a higher molecular weight than in the polymer composition C1, and the like.

The mass ratio a of the polymer composition C1 to the polymer and/or the polymer composition C2: (mass of C1)/((mass of C1) + (mass of C2)) can be appropriately designed in accordance with the required balance between the adhesive bonding characteristics and the melt viscosity, and the higher the mass ratio of a, the higher the balance between the adhesive bonding characteristics and the melt viscosity, and is therefore preferable.

The mass ratio of a is preferably 0.1 or more, more preferably 0.2 or more, further preferably 0.5 or more, further preferably 0.7 or more, and further preferably 0.8 or more.

The mass ratio of the other polymer and/or the polymer composition C2 is preferably 0.9 or less, more preferably 0.8 or less, further preferably 0.7 or less, and still further preferably 0.6 or less, because the absolute value of the holding force in the high temperature range of, for example, about 60 ℃ tends to be higher as the mass ratio is higher.

[ adhesive Binder composition ]

The adhesive composition of the present embodiment comprises 100 parts by mass of the adhesive composition for an adhesive comprising the polymer composition of the present embodiment, 50 to 400 parts by mass of an adhesion promoter, and 10 to 150 parts by mass of a softening agent.

Thus, the adhesive composition of the present embodiment can obtain an excellent balance between the adhesive property and the melt viscosity.

The content of the tackifier is preferably 100 to 380 parts by mass, more preferably 150 to 350 parts by mass.

The content of the softener is preferably 30 to 130 parts by mass, and more preferably 70 to 120 parts by mass.

(tackifier)

The tackifier constituting the adhesive composition of the present embodiment can be variously selected depending on the use and required performance of the obtained adhesive composition.

Examples of the tackifier include, but are not limited to, natural rosin, modified rosin, hydrogenated rosin, glycerol ester of natural rosin, glycerol ester of modified rosin, pentaerythritol ester of natural rosin, pentaerythritol ester of modified rosin, pentaerythritol ester of hydrogenated rosin, copolymer of natural terpene, three-dimensional polymer of natural terpene, hydrogenated derivative of copolymer of hydrogenated terpene, polyterpene resin, hydrogenated derivative of phenolic modified terpene resin, aliphatic petroleum hydrocarbon resin, hydrogenated derivative of aliphatic petroleum hydrocarbon resin, aromatic petroleum hydrocarbon resin, hydrogenated derivative of aromatic petroleum hydrocarbon resin, cyclic aliphatic petroleum hydrocarbon resin, hydrogenated derivative of cyclic aliphatic petroleum hydrocarbon resin, and the like.

These adhesion promoters may be used alone or in combination of two or more.

As the tackifier, a liquid type tackifier resin may be used as long as it has a colorless to pale yellow color, substantially no odor, and good thermal stability.

As the tackifier other than the hydrogenated derivative, for example, aliphatic resin, alicyclic resin, polyterpene, natural and modified rosin ester, and a mixture thereof are preferable, but not limited thereto. Specific examples thereof include "Wingtack Extra" manufactured by Sartomer, "Piccotac" manufactured by Eastman chemical company, "Escorez" (trade name), Escibrez "manufactured by Arizona chemical company," Sylvasum "(trade name)," Sylvalite "(trade name), and" Piccolyte "(trade name) manufactured by Ashland.

The tackifier resin is preferably a hydrogenated derivative in terms of difficulty in coloring and low degree of odor. Among them, hydrogenated dicyclopentadiene-based resins are particularly preferable. Examples of such hydrogenated derivatives include, but are not limited to, Alcon P100 (trade name) manufactured by Mitsuka Chemical, Alcon M115 (trade name), Clearon P135 (trade name) manufactured by Yasuhara Chemical, and ECR5400 (trade name) manufactured by Exxon.

In the adhesive composition of the present embodiment, when high adhesiveness and resistance to change with time of adhesive strength, creep performance, or the like are required, it is more preferable that the adhesive composition contains 20 to 75 mass% of an adhesive resin having affinity for a block (usually a mid-block) of a non-glass phase of the block copolymer and 3 to 30 mass% of an adhesive having affinity for a block (usually an outer-block) of a glass phase of the block copolymer.

As the tackifier having affinity with the block of the glass phase, a terminal block tackifier resin is preferable. Examples of the tackifier resin include homopolymers or copolymers containing vinyltoluene, styrene, α -methylstyrene, benzofuran, or indene as a resin mainly having an aromatic group. Among these, Kristalex or Plastolyn (product name, manufactured by Eastman chemical Co.) having α -methylstyrene is preferable. The content of the terminal block tackifier in the adhesive composition is preferably in the range of 3 to 30 mass%, more preferably in the range of 5 to 20 mass%, and further preferably in the range of 6 to 12 mass%.

When high initial adhesion, high wettability, low melt viscosity of the adhesive composition, high coatability, discharge stability, and the like are required, the tackifier used in the adhesive composition is preferably a petroleum resin having an aromatic group content of 3 to 12 mass%. The aromatic group content is more preferably 4 to 10% by mass, and particularly preferably hydrogenated petroleum resin.

(softening agent)

Examples of the softening agent constituting the adhesive composition of the present embodiment include, but are not limited to, oils, plasticizers, liquid tackifiers (having a ring and sphere softening point of less than 30 ℃), synthetic liquid oligomers, and mixtures thereof.

The softening agent is not particularly limited, and known paraffin-based and naphthene-based process oils and mixed oils thereof can be used.

The commercially available products are not particularly limited, and examples thereof include Diana Freesia S32 (trade name), Diana Process Oil PW-90 (trade name), Process Oil NS100 (trade name), White Oil Broom350 (trade name) manufactured by Kukdong Oil & Chem, DN Oil KP-68 (trade name), Enerper M1930 (trade name) manufactured by BPChemicals, Kaydol (trade name) manufactured by Crompton, Primol352 (trade name) manufactured by Esso, and KN4010 (trade name) manufactured by PetroChinancompany.

[ Disposable product ]

The block copolymer, the polymer composition containing the same, the adhesive composition, and the adhesive composition of the present embodiment are suitable for use in the production of disposable products.

The disposable product is not particularly limited, and examples thereof include sanitary materials such as disposable diapers, sanitary napkins, and pet pads.

The structure of the disposable product is not particularly limited, and examples thereof include the following: the adhesive composition of the present embodiment is used to bond a1 st component and a2 nd component to each other, and the adhesive composition of the present embodiment is used to bond the 1 st component and the 2 nd component to each other.

As described above, the method for bonding 2 components using the adhesive composition of the present embodiment is not particularly limited, and examples thereof include a method including the steps of: a step 1 of heating an adhesive composition to a molten state; a step 2 of applying the adhesive composition in a molten state to one of the constituent members; and a 3 rd step of laminating one component member on another component member and then cooling and solidifying the adhesive composition to thereby bond the 2 component members.

The method for applying the adhesive composition melted by heating to one component is not particularly limited, and examples thereof include spiral coating, omega coating, slot coater coating, roll coater coating, curtain spray coating, and dot coating. Among these, spiral coating, omega coating, and curtain spray coating are particularly preferable in terms of improving the hand of disposable products.

The 1 st component and the 2 nd component are not particularly limited, and examples thereof include polyolefin resin films, nonwoven fabrics, woven fabrics, natural rubbers, and hydrophilic porous base materials. Examples of the hydrophilic porous substrate include a porous substrate made of cellulose or cotton, a porous substrate subjected to hydrophilization treatment, and the like.

More specifically, the 1 st component is a topsheet and/or a backsheet, and the 2 nd component is a sheet-like absorbent body, and the absorbent article such as a diaper is formed by bonding the absorbent body to the topsheet and/or the backsheet using the adhesive composition of the present embodiment as a hot melt adhesive.

In the case of the absorbent article, the top sheet may be formed of a liquid-permeable base material having a function of allowing body fluid to move to the absorbent body, and examples thereof include materials such as a nonwoven fabric including a heat-bonded nonwoven fabric and a spunbond nonwoven fabric, a composite nonwoven fabric including a heat-bonded and spunbond laminate, an open-cell film including an open-cell polyethylene film, a foamed film including a polyethylene foam and a polyurethane foam, and a composite sheet including a laminate of these materials.

In addition, embossing or punching may be performed on the surface of the top sheet in order to improve liquid permeability.

The surface sheet preferably has a basis weight of 18g/m from the viewpoints of strength and processability²Above 40g/m²The following. The shape of the top sheet is not particularly limited as long as the top sheet is a shape that covers the absorbent body and can guide the body fluid to the absorbent body without leakage.

In the absorbent body, a plurality of convex three-dimensional shape portions are formed with the longitudinal direction in the front-rear direction of the absorbent article, and the convex three-dimensional shape portions and the top sheet are preferably joined by a hot melt adhesive. With such a configuration, the bodily fluid excreted into the absorbent body is more easily diffused in the front-back direction, and the side leakage in the width direction can be suppressed, and the fit feeling of the absorbent article can be maintained well.

The back sheet may be formed of the same material as the front sheet, but is preferably formed of a material including a liquid-permeable base material such that body fluid held by the absorber does not wet clothes, and a material such as a resin film or a composite sheet in which a resin film and a nonwoven fabric are laminated.

The nonwoven fabric used in the composite sheet is not particularly limited in the production method, and examples thereof include a spunbond nonwoven fabric, a meltblown nonwoven fabric, a spunbond/meltblown/spunbond laminated composite nonwoven fabric, and a composite material thereof.

Examples of the resin film include polyester, polyvinyl alcohol, polyethylene, polypropylene, and a composite film of polyethylene and polypropylene.

The basis weight of the back sheet is preferably 15g/m from the viewpoints of strength and processability²Above 40g/m²The following. In order to prevent stuffiness when worn, the back sheet is preferably provided with air permeability by blending a filler (for example, calcium carbonate) into a resin film of a specific base material or by embossing.

The absorbent body preferably contains absorbent fibers as a base material and a Super Absorbent Polymer (SAP). The absorbent fiber is not particularly limited as long as it is an absorbent fiber generally used in absorbent articles such as sanitary napkins, disposable diapers, and incontinence pads, and examples thereof include fluff pulp, cotton, rayon, acetate, tissue paper, absorbent paper, and hydrophilic nonwoven fabric. In the absorbent fiber of the absorbent body, the basis weight is preferably 100g/m in order to not impair the absorption performance and the touch²Above 800g/m²The following.

The absorbent polymer contained in the absorbent body is not particularly limited as long as it can absorb body fluid and prevent backflow, and an absorbent body formed of a material such as a sodium polyacrylate type, a polyaspartate type, (starch-acrylic acid) graft copolymer, (acrylic acid-vinyl alcohol) copolymer, (isobutylene-maleic anhydride) copolymer, and a saponified product thereof can be used. Among these, sodium polyacrylate-based is preferable in terms of absorption amount per unit weight. Regarding the amount of SAP in the absorbent body, in order not to impair absorptionThe shrinkage and touch are preferably 50g/m²Above 500g/m²The basis weight is preferably 15 to 50 mass%.

As the structure of the absorbent body, a structure in which SAP particles are mixed in absorbent fibers, or an SAP sheet in which SAP particles are fixed between absorbent fibers is preferable. In some cases, the absorbent body is wrapped in a carrier sheet for the purpose of preventing leakage of SAP particles and stabilizing the shape of the absorbent body, and in this case, the carrier sheet exposed on the surface is bonded to the front sheet and/or the back sheet with a hot melt adhesive.

The method for producing the absorbent article may be a general method, and examples thereof include a production method having the following steps: (A) a step of forming an absorbent body by stacking absorbent fibers and absorbent polymers together to produce an absorbent body pad; (B) fixing and integrating the surface sheet and the elastic member forming the three-dimensional gathers by a hot-melt adhesive; (C) a step of applying a hot-melt adhesive to the inner sides of the front sheet, the elastic member, and the back sheet; (D) a step of arranging a front sheet on the upper part of the absorber and a back sheet on the lower part of the absorber in the collecting drum, and fixing and integrating the components; (E) and cutting the semi-finished product of the absorbent article by a cutting device according to the product size, and cutting off each absorbent article.

[ production methods of Block copolymer and Polymer composition ]

The method for producing the block copolymer of the present embodiment and the polymer composition containing the block copolymer is not particularly limited, and a known method can be used.

Examples thereof include the methods described in Japanese patent publication No. 36-19286, Japanese patent publication No. 43-17979, Japanese patent publication No. 46-32415, Japanese patent publication No. 49-36957, Japanese patent publication No. 48-2423, Japanese patent publication No. 48-4106, Japanese patent publication No. 51-49567, and Japanese patent publication No. 59-166518.

The modified polymer having a functional group is obtained by addition reaction of a modifier described later with the living end of the polymer obtained by these methods.

The following examples illustrate a method for producing a polymer composition containing a block copolymer comprising a polymer block mainly composed of a vinyl aromatic monomer unit and a polymer block mainly composed of a conjugated diene monomer unit.

Examples of the method for producing the polymer composition of the present embodiment include a method including the steps of:

a polymerization step of copolymerizing a vinyl aromatic hydrocarbon compound such as styrene and a conjugated diene compound such as butadiene in an inert hydrocarbon solvent using an organolithium compound as a polymerization initiator to obtain a block copolymer; and

a modification step (coupling step) of reacting the obtained block copolymer with a modifier (collectively referred to as a modifier when 1 or more polymers are bonded to the compound, and also referred to as a coupling agent when 2 or more polymers are bonded to the modifier).

In this case, the polymer composition of the present embodiment can be obtained by using, as the coupling agent, for example, a compound having a structure of the above formula (Y1) or (Y2).

[ solution 29]

[ solution 30]

(in the general formulae (Y1) and (Y2), the curved portion is a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, which may be unsubstituted or substituted; Z is a functional group which can be eliminated by a coupling reaction; and X is a group 1 element.)

The general formula (Y1) is preferably represented by the following general formula (Y-I), and the general formula (Y2) is preferably represented by the following general formula (Y-II).

[ solution 31]

[ solution 32]

(in the formulae (Y-I) and (Y-II), R₁、R₂Is hydrogen or C1-20 unsubstituted or substituted saturated or unsaturated alkyl, R₁And R₂May be independent of each other or may form a ring structure. Z is a functional group which can be eliminated by a coupling reaction. In addition, X is a group 1 element. )

The formation process of each structure of the block copolymer contained in the polymer composition will be described. When the coupling agent represented by the above general formula (Y1) or (Y2) is used, the polymer having an active end is reacted with a carbonyl moiety as a first stage to obtain the structure represented by the above general formula (1).

In the second stage, the polymer having an active end is further reacted with the carbonyl moiety of the general formula (1) which has been reacted in the first stage, thereby obtaining the structure represented by the general formula (2).

In addition, as a second stage, a polymer having an active end is further reacted with a carbonyl moiety on the side of the general formula (1) on which the reaction did not occur in the first stage, thereby obtaining a structure represented by the general formula (3).

As the third stage, the polymer having an active end is further reacted with the remaining carbonyl moiety in the general formula (2) or the general formula (3), thereby obtaining the structure represented by the general formula (4).

In addition, when the coupling agent represented by the general formula (Y1) or (Y2) is used, it is preferable because the adhesive composition tends to exhibit a high holding force when 2 polymers having the structure of the general formula (2) are condensed to form 4-branched units and the polymer composition containing 4-branched units is used as the adhesive composition.

As described above, the reaction with the coupling agent having the structure of the general formula (Y1) or (Y2) produces a mixture of a polymer having 1 polymer chain bonded to the coupling agent and a branched chain body having 2 to 4 polymer chains bonded to the branched chain body. When the block copolymer of the present embodiment is used for an application of an adhesive composition, the respective components can exert functions even when they are simple substances, but when they are used in the form of a polymer composition containing polymers of plural structures, the melt viscosity and the holding power are balanced, and the block copolymer tends to function as a preferable adhesive composition.

The coupling agent having the structure of the above general formula (Y1) or (Y2) is not particularly limited, and examples thereof include 4-methylhexahydrophthalic anhydride, methylbicyclo [2.2.1] heptane-2, 3-dicarboxylic anhydride/bicyclo [2.2.1] heptane-2, 3-dicarboxylic anhydride, bicyclo [2.2.1] heptane-2, 3-dicarboxylic anhydride/bicyclo [2.2.1] heptane-2, 3-dicarboxylic anhydride, octenylsuccinic anhydride, 1, 2, 3, 6-tetrahydrophthalic anhydride, and the like.

As the modifier or coupling agent which forms the block copolymer represented by the above general formulae (1) to (4) by the modification reaction and the coupling reaction, in addition to the coupling agent having the structure represented by the above general formula (Y1), a compound having the structure of the general formula (Y2) having a structure in which an — O-bond portion in the above general formula (Y1) is ring-opened, or a derivative thereof, and a modifier having 1 or more carboxyl groups and 1 or more ester groups in a molecule can be suitably used.

Examples of the modifier include a general dicarboxylic acid compound, an acid anhydride compound, a diester compound, and a carboxylate compound.

Examples of the dicarboxylic acid compound include succinic acid and maleic acid, and examples of the acid anhydride compound include succinic anhydride, maleic anhydride, phthalic anhydride, and octenyl succinic anhydride.

The weight average molecular weight of the polymer composition can be adjusted by controlling the amount of the polymerization initiator such as an organolithium compound added.

After the polymerization reaction is completed, the coupling reaction is performed, the active species is inactivated by adding water, alcohol, acid, or the like, the polymerization solvent is separated by, for example, stripping, and then the polymer composition is dried.

The polymerization method of the polymer composition is not particularly limited, and examples thereof include polymerization methods such as coordination polymerization, anionic polymerization, and cationic polymerization. Among these, anionic polymerization is preferable in terms of ease of structure control. As the method for producing the block copolymer component by anionic polymerization, known methods can be used, and there are no particular limitations thereon, and examples thereof include the methods described in Japanese patent publication No. 36-19286, Japanese patent publication No. 43-17979, Japanese patent publication No. 46-32415, Japanese patent publication No. 49-36975, Japanese patent publication No. 48-2423, Japanese patent publication No. 48-4106, Japanese patent publication No. 56-28925, Japanese patent publication No. 59-166518, and Japanese patent publication No. 60-186577.

The inert hydrocarbon solvent used in the polymerization step of the polymer composition is not particularly limited, and examples thereof include: aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane, and isooctane; alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane; and hydrocarbon solvents such as aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene. These may be used alone or in combination of two or more.

The organolithium compound used as a polymerization initiator in the polymerization step of the polymer composition is not particularly limited, and known compounds such as ethyllithium, propyllithium, N-butyllithium, sec-butyllithium, tert-butyllithium, phenyllithium, propenyllithium, and hexyllithium can be used. N-butyllithium and sec-butyllithium are particularly preferable.

The organic lithium compound may be used alone or as a mixture of two or more thereof.

In the method for producing a polymer composition of the present embodiment, a step of deashing metals derived from a polymerization initiator or the like may be employed as necessary.

In the method for producing the polymer composition of the present embodiment, a step of further adding an antioxidant, a neutralizer, a surfactant, and the like as necessary may be employed.

Examples of the antioxidant include, but are not limited to, hindered phenol compounds, phosphorus compounds, and sulfur compounds similar to those described below.

Examples of the neutralizing agent include, but are not limited to, various metal stearates, hydrotalcite, benzoic acid, and the like.

Examples of the surfactant include, but are not limited to, anionic surfactants, nonionic surfactants, and cationic surfactants. Examples of the anionic surfactant include, but are not limited to, fatty acid salts, alkyl sulfate salts, and alkylaryl sulfonates. Examples of the nonionic surfactant include, but are not limited to, polyoxyethylene alkyl ethers and polyoxyethylene alkylaryl ethers. Examples of the cationic surfactant include, but are not limited to, alkylamine salts and quaternary ammonium salts.

After the polymer composition of the present embodiment is produced as described above, the block polymer is separated, that is, finished, by a method described later.

In the case where the polymerization step of the polymer composition is carried out in an inert hydrocarbon solvent, the inert hydrocarbon solvent is removed to separate the polymer composition. As a specific method for removing the solvent, steam stripping can be mentioned. By steam stripping, an aqueous pellet is obtained, and the obtained aqueous pellet is dried, whereby a polymer composition can be obtained. In the steam stripping, as the aggregating agent, a surfactant is preferably used. Examples of such a surfactant include, but are not limited to, the same anionic surfactants, cationic surfactants, and nonionic surfactants as described above. These surfactants may be added in an amount of usually 0.1 to 3000ppm based on the water in the stripping belt. In addition to the surfactant, a water-soluble salt of a metal such as Li, Na, Mg, Ca, Al, or Zn may be used as a dispersing aid for the aggregates.

The concentration of the polymer composition in the form of pellets dispersed in water obtained by the polymerization step of the polymer composition and the above-mentioned stripping is usually 0.1 to 20% by mass (relative to the proportion of water in the stripping zone). Within this range, pellets having a good particle size can be obtained without causing operational problems. The polymer composition pellets are preferably dehydrated to a water content of 1 to 30 mass%, and then dried until the water content becomes 1 mass% or less. In the dehydration step of the pellets, dehydration may be performed by an extrusion dehydrator such as a roll, a banbury dehydrator or a screw extruder type press dehydrator, or dehydration and drying may be performed simultaneously by a conveyor or a box-type hot air dryer.

As described above, the block copolymer of the present embodiment is obtained by polymerizing the polymer and reacting the polymer with a coupling agent represented by the above formula (Y1) or (Y2), or a modifying agent or coupling agent having 1 or more carboxyl groups and 1 or more ester groups in the molecule.

The block copolymer is produced in the form of a mixture with a polymer before the coupling reaction or a side reactant (polymer composition C1) in many cases, but can be preferably used in the form of a polymer composition containing such a side reactant in applications as an adhesive composition or the like.

On the other hand, the manner of mixing with the polymer of other structure and/or the polymer composition C2 which enhances and/or supplements the performance of the polymer composition C1 of the present embodiment is a preferable manner according to the purpose of use of the adhesive binder composition.

For example, when the polymer composition C1 has a high holding power at 40 ℃ but has a low holding power at 60 ℃, a polymer having a high holding power at 60 ℃ and/or the polymer composition C2 may be mixed to supplement the high holding power.

In this case, as the polymer and/or polymer composition C2, an aromatic vinyl polymer or a polymer and/or polymer composition obtained by reacting a copolymer containing an aromatic vinyl monomer and a conjugated diene monomer with a coupling agent is preferable. That is, since the polymer and/or polymer composition C2 is a polymer and/or polymer composition having a polymer structure and/or modifier structure different from that of the polymer composition C1 and is a mixture of 1-branched chain bodies (for example, diblock bodies) and 2 to 4-branched chain bodies, the polymer and/or polymer composition C2 can exhibit adhesive properties even with only C2, and therefore, by selecting a substance that can enhance and/or complement the properties of the polymer composition C1 as the polymer and/or polymer composition C2, an adhesive composition that can obtain more preferable adhesive properties can be constituted.

As a method for producing such an adhesive composition, for example, a method of dry blending pellets of the polymer composition C1 with pellets of the adhesive polymer and/or the polymer composition C2 is preferable because the properties can be easily adjusted.

The mixing ratio of the polymer composition C1 and the polymer and/or the polymer composition C2 is not particularly limited, and may be appropriately set according to the properties and the purpose of each composition, and from the viewpoint of clarifying the effect of the mixing, (mass of C1)/((mass of C1) + (mass of C2)) is preferably mixed in a range of 0.1 to 0.9, and as described above, in the pressure-sensitive adhesive composition, a tackifier, a softener, or the like may be added in addition to the polymer compositions C1 and C2.