JP6483529B2 - Block copolymer crumb and process for producing the same - Google Patents

Description

  The present invention relates to a block copolymer crumb and a method for producing the same.

  Conventionally, a block copolymer consisting of a polymer block mainly composed of a conjugated diene monomer and a polymer block mainly composed of a vinyl aromatic monomer or a hydrogenated product thereof has not been vulcanized. However, it has the same elasticity as vulcanized natural rubber and synthetic rubber at room temperature, and has excellent processability similar to that of thermoplastic resin at high temperatures, so footwear, plastic modifiers, asphalt modified Widely used in fields such as quality materials and adhesives, household products, packaging materials for home appliances and industrial parts, toys, etc.

  The block copolymer or hydrogenated product thereof is commercially available in various forms such as pellets and crumbs, and among them, the crumb block copolymer or hydrogenated product thereof is porous and excellent in solubility. For example, it is suitably used in fields such as asphalt modifiers and adhesives.

  Many proposals have hitherto been made regarding a method for obtaining such a crumb of a block copolymer or a hydrogenated product thereof (hereinafter also referred to as “block copolymer crumb”).

  For example, after removing the solvent from the solution of the block copolymer obtained by the polymerization step and the hydrogenation step by steam stripping, the solvent is further dehydrated and dried by an extrusion dehydrator, so that the water content is 1% by mass or less. A method for obtaining a combined crumb is known (see, for example, Patent Documents 1 and 2).

  In addition, as a method of improving the oil-absorbing property of the high molecular weight hydrogenated block copolymer crumb, the operating temperature of the extruder for dehydrating the hydrogenated block copolymer crumb and the water content of the slurry before charging the extruder were adjusted. Dehydration / drying method using an extrusion dehydrator (see, for example, Patent Document 3), and further, a method of drying a hydrogenated block copolymer crumb with a hot air dryer under a specific temperature condition (for example, Patent Documents 4 and 5). Have been proposed).

  In addition, a block copolymer composition as an asphalt modifier having a specific range of bulk density, particle size distribution, and pore volume, good solubility in asphalt, and excellent workability thereafter. It is known (see, for example, Patent Document 6).

  Further, a hydrogenated block copolymer porous crumb having a bulk density and a pore volume equal to or higher than a specific value, absorbing a softener and a plasticizer uniformly and in a short time and having good handling properties is known (for example, (See Patent Document 7).

  Furthermore, hydrogenated block copolymer crumbs having a specific range of size distribution and specific surface area and excellent oil absorption uniformity are known (for example, see Patent Document 8).

JP-A 64-56713 Japanese Patent Laid-Open No. 2-189304 Japanese translation of PCT publication No. 2002-542963 International Publication No. 99/55752 International Publication No. 01/30859 JP-A-8-301929 JP-A-11-315187 International Publication 2012/056939

  However, crumbs obtained by the methods disclosed in Patent Documents 1 and 2 have not yet obtained sufficient characteristics regarding compatibility with asphalt, tackifiers, softeners, and the like. There is room for improvement for use in adhesives and the like.

  In addition, the high molecular weight hydrogenated block copolymer crumb obtained by the methods disclosed in Patent Documents 3, 4, 5 and 6 is an oil dispersion in the crumb when compounded with a thermoplastic resin or oil. Becomes non-uniform, and further, the crumb cannot be completely melted, so that it remains as an unmelted polymer.

  Moreover, the block copolymer crumbs obtained by the methods disclosed in Patent Documents 4, 5, and 6 are inferior in heat discoloration resistance required for applications such as adhesives.

  Moreover, the block copolymer composition disclosed in Patent Document 7 has a problem that the dissolution time with asphalt is long.

  Furthermore, the block copolymer crumb obtained by the method disclosed in Patent Document 8 is inferior in the dissolution rate required for applications such as asphalt modification and adhesives.

  Therefore, in view of the problems of the prior art as described above, the present invention can be used in a short time with asphalt, a tackifier, a softener, and the like when used in the field of asphalt modifiers, adhesives, and the like. It aims at providing the block copolymer crumb which melt | dissolved and was further excellent in the heat discoloration resistance calculated | required, for example by uses, such as an adhesive agent, and the manufacturing method of the said block copolymer crumb.

  As a result of intensive studies on the block copolymer crumb and the method for producing the block copolymer crumb in order to solve the above-described problems of the prior art, the present inventor has obtained melt viscosity, size distribution, specific surface area, voids of crumb. It has been found that a block copolymer crumb having a specific ratio and a ratio of voids having a specific size can solve the above-mentioned problems of the prior art, and has completed the present invention.

  That is, the present invention is as follows.

1. A block copolymer crumb containing a block copolymer containing a vinyl aromatic hydrocarbon unit and a conjugated diene unit, or a hydrogenated product thereof and satisfying the following (1) to (4).
(1) The melt viscosity at 150 ° C. and 100 s ⁻¹ measured by a capillograph is 1.0 × 10 ^{3 to} 1.0 × 10 ⁴ Pa · s,
(2) The component that passes through a sieve having an opening of 2.0 mm and does not pass through a sieve having an opening of 0.6 mm is 50% by mass or more of the total crumb, and further passes through a sieve having an opening of 0.6 mm. Ingredients are 10% by weight or less of the total crumb,
(3) Specific surface area is 0.05-0.30 m ² / g,
(4) The void ratio is 0.01 to 0.20, and voids having a diameter of 100 μm or more occupy 0.2 to 15% by volume of the total voids.

2. 2. The block copolymer crumb according to 1 above, having a bulk density of 0.25 to 0.70 g / mL.

3. 3. The block copolymer crumb according to 1 or 2 above, wherein the component having an aspect ratio of 1.5 to 5.0 is 50% by mass or more based on the total mass of the crumb.

4). Having a step of producing a crumb by extrusion drying the block copolymer or its hydrogenated product using an extrusion dryer provided with a die having an opening at the outlet;
The diameter of the circle circumscribing the opening of the die is 0.5 to 2.5 mm,
A die shape factor obtained by dividing the total side length of the opening of the die by the opening area of the die is 0.4 to 4.0 mm ⁻¹ ;
The block copolymer crumb according to 1 above, wherein the temperature at the outlet of the extruder is 130 ° C or higher, and the moisture content of the crumb at the outlet of the extruder is 2.0% by mass or higher. Production method.

5. 5. The method for producing a block copolymer crumb according to 4 above, wherein the temperature at the exit of the extrusion dryer in the extrusion drying step is 130 to 180 ° C.

6). 6. The method for producing a block copolymer crumb according to 4 or 5 above, wherein the moisture content of the crumb at the exit of the extrusion dryer in the extrusion drying step is 2.0 to 30% by mass.

7). Before the extrusion drying step,
Removing the solvent from the solution of the block copolymer or its hydrogenated product by steam stripping; and
Separating the stripping water from the aqueous slurry of the block copolymer or hydrogenated product obtained by the solvent removal step to obtain a hydrous crumb of the block copolymer or hydrogenated product;
The method for producing a block copolymer crumb according to any one of 4 to 6 above.

8). After the extrusion drying step,
The block copolymer crumb according to any one of 4 to 7 above, comprising a step of drying the crumb obtained by extrusion drying to obtain a crumb having a water content of 0.01% by mass or more and less than 2.0% by mass. Manufacturing method.

  According to the present invention, when used in the field of asphalt modifiers, adhesives, etc., it is a block copolymer that dissolves in a short time with asphalt, tackifiers, softeners, etc. and has excellent heat discoloration resistance. A polymer crumb can be provided.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as the present embodiment) will be described. The following embodiment is an exemplification for explaining the present invention, and the present invention is not limited to the following embodiment. The present invention can be implemented with appropriate modifications within the scope of the gist.

[Block copolymer crumb]
The block copolymer crumb of this embodiment (sometimes referred to simply as “crumb” in the present specification) is a block copolymer containing a vinyl aromatic hydrocarbon unit and a conjugated diene unit, or a hydrogenated product thereof. The following (1) to (4) are satisfied.
(1) The melt viscosity at 150 ° C. and 100 s ⁻¹ measured by a capillograph is 1.0 × 10 ^{3 to} 1.0 × 10 ⁴ Pa · s,
(2) The component that passes through a sieve having an opening of 2.0 mm and does not pass through a sieve having an opening of 0.6 mm is 50% by mass or more of the total crumb, and further passes through a sieve having an opening of 0.6 mm. Ingredients are 10% by weight or less of the total crumb,
(3) Specific surface area is 0.05-0.30 m ² / g,
(4) The void ratio is 0.01 to 0.20, and voids having a diameter of 100 μm or more occupy 0.2 to 15% by volume or less of the total voids.

As shown in the above (1), the block copolymer crumb in this embodiment has a melt viscosity at 150 ° C. and 100 s ⁻¹ (hereinafter, also simply referred to as “melt viscosity”) measured by a capillograph of 1.0 × 10. ^{3 to} 1.0 × 10 ⁴ Pa · s, preferably 1.2 × 10 ^{3 to} 9.0 × 10 ³ Pa · s, more preferably 2.0 × 10 ^{3 to} 8.0 × 10 ³ Pa. -S. If the melt viscosity is 1.0 × 10 ⁴ Pa · s or less, the heat discoloration resistance is excellent, while if it is 1.0 × 10 ³ Pa · s or more, the dissolution time can be shortened. The melt viscosity can be controlled by adjusting the molecular weight, for example, and can be controlled by the number of functional groups in the case of a coupling type block copolymer described later. The melt viscosity tends to increase as the molecular weight increases, and increases as the number of functional groups decreases. A specific method for measuring the melt viscosity will be described in Examples described later.

  From the viewpoint of shortening the dissolution time with asphalt, tackifier, softener and the like, the block copolymer crumb of this embodiment passes through a sieve having an opening of 2.0 mm as shown in (2) above. And the component which does not pass the sieve of 0.6 mm of openings is 50 mass% or more of all crumbs, and the component which passes the sieve of 0.6 mm of openings is 10 mass% or less of all crumbs. Preferably, the component that passes through a sieve having an aperture of 2.0 mm and does not pass through a sieve having an aperture of 0.6 mm is 54% by mass or more of the total crumb, and the components that pass through the sieve having an aperture of 0.6 mm are all It is 8 mass% or less of crumb. More preferably, the component that passes through a sieve having an aperture of 2.0 mm and does not pass through a sieve having an aperture of 0.6 mm is 58% by mass or more of the total crumb, and the component that passes through a sieve having an aperture of 0.6 mm It is 6 mass% or less of the total crumbs. When there are too many components that do not pass through a sieve having a mesh size of 2.0 mm (a crumb component having a large size and uneven foaming) and / or components that pass through a sieve having a mesh size of 0.6 mm (hard and easy to dissolve) When there are too many components), dissolution time will become long.

The block copolymer crumb of this embodiment has a specific surface area of 0.05 to 0.3 m ² / g, preferably 0.05 to 0.25 m ² / g, as shown in (3) above. Preferably it is 0.06-0.20 m < ² > / g. If a specific surface area of 0.05 m ² / g or more, the dissolution time can be shortened, whereas resistance to heat discoloration resistance is excellent if 0.3 m ² / g or less.

As shown in the above (4), the block copolymer crumb of this embodiment has a porosity of 0.01 to 0.20, and voids having a diameter of 100 μm or more are 0.2 to 15% by volume of the total voids. It is. The void ratio is preferably 0.02 to 0.18, more preferably 0.06 to 0.16, and voids having a diameter of 100 μm or more are preferably 0.3 to 14% by volume with respect to the total void volume. More preferably, it is 0.5-13 volume% or less. When the porosity is 0.20 or less and the voids having a diameter of 100 μm or more are 15% by volume or less of the total voids, the dissolution time can be shortened and the heat discoloration resistance is excellent. On the other hand, when the porosity is 0.01 or more and the voids having a diameter of 100 μm or more are 0.2% by volume or more of the total voids, the dissolution time can be shortened.
In addition, the porosity of the block copolymer crumb of the present embodiment indicates the ratio of the internal space of the crumb to the crumb volume (space volume in the crumb volume / crumb volume), and the space leading to the crumb surface, And a space that does not communicate with the crumb surface. Here, the crumb volume means the sum of the crumb structure volume and the spatial volume within the crumb volume.

  The block copolymer crumb of the present embodiment preferably has a bulk density of 0.25 to 0.70 g / mL. More preferably, it is 0.27-0.65 g / mL, More preferably, it is 0.29-0.60 g / mL. A bulk density of 0.25 g / mL to 0.70 g / mL is preferable because the dissolution time is shortened.

  In the block copolymer crumb of this embodiment, the crumb component having an aspect ratio of 1.5 to 5.0 is preferably 50% by mass or more (including 100% by mass) of the entire crumb, and 55% by mass or more. More preferably, it is more preferably 60% by mass or more. An aspect ratio of 1.5 to 5.0 is preferable because dissolution time is shortened.

  The content of the component of the block copolymer crumb that passes through a sieve with an aperture of 2.0 mm and does not pass through the sieve with an aperture of 0.6 mm, the content of a component that passes through the sieve of an aperture of 0.6 mm, the specific surface area The measurement method of the porosity, the ratio of the voids having a diameter of 100 μm or more to the total voids, the bulk density, and the aspect ratio will be described in detail in Examples described later.

  The content of the component of the block copolymer crumb that passes through a sieve with an aperture of 2.0 mm and does not pass through the sieve with an aperture of 0.6 mm, the content of a component that passes through the sieve of an aperture of 0.6 mm, the specific surface area The porosity, the proportion of voids having a diameter of 100 μm or more, the bulk density, and the aspect ratio can be controlled by controlling the production conditions of the step of crumbizing the block copolymer. A method for producing crumb will be described later.

[Method for producing block copolymer crumb]
The method for producing a block copolymer crumb according to this embodiment includes a step of extrusion drying the block copolymer under predetermined conditions, and preferably a step of producing the block copolymer before the extrusion drying step. Have

(Process for producing block copolymer)
First, the process for producing a block copolymer will be described. The block copolymer is obtained by a polymerization reaction between a vinyl aromatic hydrocarbon and a conjugated diene compound.

<Polymerization reaction>
The block copolymer can be produced by polymerizing vinyl aromatic hydrocarbon and conjugated diene in a hydrocarbon solvent using an organolithium compound as a polymerization initiator.

  Examples of the vinyl aromatic hydrocarbon include styrene, α-methylstyrene, p-methylstyrene, 2-vinylnaphthalene, divinylbenzene, and the like. These may be used alone or in combination of two or more.

  Examples of the conjugated diene include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3 butadiene, 1,3-pentadiene, 1,3-heptadiene, and the like. These may be used alone or in combination of two or more.

  Examples of the method for producing the block copolymer include Japanese Patent Publication No. 36-19286, Japanese Patent Publication No. 43-17879, Japanese Patent Publication No. 46-32415, Japanese Patent Publication No. 49-36957, and Japanese Patent Publication No. 48-2423. Examples thereof include methods described in Japanese Patent Publication Nos. 48-4106, 51-49567, 59-166518, and the like.

Examples of the structure of the block copolymer include general formulas (AB) _n , (AB) _n -A, B- (AB) _n , [(AB) _n ] _m X, [ (B-A) _{n] m} X, [(A-B) _n -A] _m X, include those represented by [(B-A) _n -B] _m X.
A is a polymer block A mainly composed of vinyl aromatic hydrocarbons, and B is a polymer block B mainly composed of conjugated dienes. The boundary between the polymer block A and the polymer block B does not necessarily have to be clearly distinguished. N is an integer of 1 or more, and m is an integer of 2 or more. X is, for example, silicon tetrachloride, tin tetrachloride, epoxidized soybean oil, polyhalogenated hydrocarbon compound, carboxylic acid ester compound, polyvinyl compound, bisphenol type epoxy compound, alkoxysilane compound, halogenated silane compound, ester compound. Represents a residue of a polyfunctional coupling agent such as a coupling agent, or the like, or a residue of an initiator such as a polyfunctional organolithium compound. Initiators such as polyfunctional coupling agents and polyfunctional organolithium compounds may be used alone or in combination of two or more.

For example, in the case of a radial block copolymer having the residue X of the polyfunctional coupling agent, all the functional groups of the used polyfunctional coupling agent may not be reacted. For example, when a radial block copolymer is produced using a tetrafunctional coupling agent, the resulting radial block copolymer is (AB) ₄ X, (AB) ₃ X, (AB) _It may be at least one block copolymer selected from the group consisting of ₂ X and A-B-X, or a mixture of two or more block copolymers.

  In the above, the polymer block A mainly composed of vinyl aromatic hydrocarbons contains 50% by mass or more of vinyl aromatic hydrocarbons, and preferably contains 70% by mass or more of vinyl aromatic hydrocarbons and conjugated dienes. A copolymer block and / or a vinyl aromatic hydrocarbon homopolymer block.

  The polymer block B mainly composed of a conjugated diene contains a conjugated diene in an amount exceeding 50% by mass, and preferably contains 60% by mass or more of a copolymer block of a conjugated diene and a vinyl aromatic hydrocarbon. And / or a conjugated diene homopolymer block.

  When the polymer block A and / or the polymer block B is a copolymer block of a vinyl aromatic hydrocarbon and a conjugated diene, the vinyl aromatic hydrocarbon in the copolymer block is uniformly distributed. Alternatively, it may be distributed in a tapered shape. In the copolymer block portion, a plurality of portions where the vinyl aromatic hydrocarbons are uniformly distributed and / or a portion where the portions are distributed in a tapered shape may coexist.

  A plurality of portions having different vinyl aromatic hydrocarbon contents may coexist in the copolymer block portion.

  The block copolymer constituting the block copolymer crumb of this embodiment may be an arbitrary mixture of block copolymers represented by the above general formula.

  10-90 mass% is preferable, as for content of the vinyl aromatic hydrocarbon unit in the block copolymer which comprises the block copolymer crumb of this embodiment, 12-70 mass% is more preferable, 15-60 mass % Is more preferable. When the content of the vinyl aromatic hydrocarbon unit is 10% by mass or more, the mechanical strength of the asphalt composition or the adhesive composition is excellent without insufficient cohesive strength of the vinyl aromatic hydrocarbon polymer block. . On the other hand, when the content of the vinyl aromatic hydrocarbon unit is 90% by mass or less, it is possible to suppress the storage stability in the asphalt composition and the decrease in tack in the adhesive composition. .

  The ratio of vinyl aromatic hydrocarbon polymer blocks incorporated in the block copolymer constituting the block copolymer crumb of this embodiment to the total vinyl aromatic hydrocarbons (referred to as the block ratio of vinyl aromatic hydrocarbons) is 50 mass% or more is preferable, and it is preferable to adjust to 70-99 mass% more preferably. Thereby, when it mixes with a predetermined material and it is set as a polymer composition, a rubber-like polymer composition with favorable softness | flexibility and a polymer composition excellent in the balance of impact resistance and rigidity are obtained.

  The block ratio (% by mass) of the vinyl aromatic hydrocarbon is determined by (mass of vinyl aromatic hydrocarbon polymer block) / (mass of all vinyl aromatic hydrocarbons constituting the block copolymer) × 100. It is done.

  The block ratio of vinyl aromatic hydrocarbons is measured by a method of oxidatively decomposing a block copolymer with tertiary butyl peroxide using osmium tetroxide as a catalyst (IM KOLTHOFF, et al., J. Polym. Sci). .1,429 (1946)).

  The microstructure (ratio of cis, trans, vinyl) of the conjugated diene polymer incorporated in the block copolymer of the present embodiment can be arbitrarily changed by using a polar compound described later.

  When 1,3-butadiene is used as the conjugated diene, the amount of 1,2-vinyl bonds in the block copolymer (ratio of conjugated diene units derived from 1,2-vinyl bonds in the conjugated diene) is 8 It is preferably -80% by mass, more preferably 10-75% by mass, and when isoprene is used as the conjugated diene or when 1,3-butadiene and isoprene are used, 1,2-vinyl The total amount of bonds and 3,4-vinyl bonds (the ratio of the total of conjugated diene units derived from 1,2-vinyl bonds and 3,4-vinyl bonds in the conjugated dienes) is 3 to 80% by mass. Preferably, it is 5-70 mass%.

The microstructure of the conjugated diene polymer incorporated in the block copolymer is a carbon disulfide solution as the block copolymer, and an infrared spectrum is measured in the range of 600 to 1000 cm ⁻¹ using a solution cell, It can obtain | require according to the calculation formula of the method of Hampton (styrene-butadiene copolymer) by the light absorbency in a predetermined wave number.

  Hydrocarbon solvents used for the production of block copolymers include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane, isooctane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, etc. An alicyclic hydrocarbon or an aromatic hydrocarbon solvent such as benzene, toluene, ethylbenzene or xylene can be used. These may be used alone or in combination of two or more.

  The organic lithium compound used as a polymerization initiator for the polymerization of the block copolymer is a compound in which one or more lithium atoms are bonded in the molecule, for example, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium. , Sec-butyl lithium, tert-butyl lithium, hexamethylene lithium, butadienyl dilithium, isoprenyl dilithium and the like. These may be used alone or in combination of two or more. Further, the organolithium compound may be added in portions during the polymerization in the production of the block copolymer.

  In the production of the block copolymer, a predetermined polar compound can be used for the purpose of adjusting the polymerization rate, changing the microstructure of the polymerized conjugated diene moiety, and the like.

  Examples of the polar compound include ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis (2-oxolanyl) propane; Tertiary amine compounds such as methylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, quinuclidine; alkali metal alkoxide compounds such as potassium tert-amylate, potassium tert-butylate, sodium tert-butylate, sodium amylate A phosphine compound such as triphenylphosphine; These may be used alone or in combination of two or more.

  The polymerization temperature for producing the block copolymer is preferably -10 to 150 ° C, more preferably 20 to 120 ° C. The time required for polymerization varies depending on the conditions, but is preferably within 48 hours, more preferably 0.2 to 10 hours. The polymerization atmosphere is preferably an inert gas atmosphere such as nitrogen gas. The polymerization pressure is not particularly limited as long as it is carried out within a range of pressure sufficient to maintain the monomer and solvent in a liquid phase within the above polymerization temperature range. Furthermore, it is preferable that impurities that inactivate the catalyst and the living polymer, for example, water, oxygen, carbon dioxide gas, and the like are not mixed in the polymerization system.

<Hydrogenation reaction>
In this embodiment, after obtaining a block copolymer by the above <polymerization reaction>, a proton donor such as alcohol or water is added, and then a hydrogenation reaction is performed using a hydrogenation catalyst described later. Thus, a hydrogenated block copolymer may be obtained.

  The hydrogenation catalyst is not particularly limited and is conventionally known (1) A supported heterogeneous hydrogen catalyst in which a metal such as Ni, Pt, Pd, or Ru is supported on carbon, silica, alumina, diatomaceous earth, or the like. (2) So-called Ziegler type hydrogenation catalyst using an organic acid salt such as Ni, Co, Fe, Cr or a transition metal salt such as acetylacetone salt and a reducing agent such as organic aluminum, (3) Ti, Ru Homogeneous hydrogenation catalysts such as so-called organometallic complexes such as organometallic compounds such as Rh and Zr are used.

  Specific examples of the hydrogenation catalyst include Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-337970, and Japanese Patent Publication No. 1-35381. The hydrogenation catalyst described in JP-B-2-9041 can be used. Preferred hydrogenation catalysts include a mixture with a titanocene compound and / or a reducing organometallic compound.

  As the titanocene compound, compounds described in JP-A-8-109219 can be used. For example, (substituted) cyclopentadidi such as biscyclopentadienyl titanium dichloride and monopentamethylcyclopentadienyl titanium trichloride. Examples thereof include compounds having at least one ligand having an enyl skeleton, an indenyl skeleton, or a fluorenyl skeleton.

  Examples of the reducing organometallic compound include organic alkali metal compounds such as organolithium, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds.

  The hydrogenation reaction is preferably carried out in a temperature range of 0 to 200 ° C, more preferably 30 to 150 ° C. The pressure of hydrogen used for the hydrogenation reaction is preferably 0.1 to 15 MPa, more preferably 0.2 to 10 MPa, and still more preferably 0.3 to 5 MPa. The hydrogenation reaction time is preferably 3 minutes to 10 hours, more preferably 10 minutes to 5 hours. The hydrogenation reaction can be any of a batch process, a continuous process, or a combination thereof.

  The total hydrogenation rate after hydrogenation of the unsaturated double bond based on the conjugated diene compound incorporated in the block copolymer before hydrogenation can be arbitrarily selected according to the purpose and is not particularly limited. Preferably 70 mol% or more, more preferably 80 mol% or more, more preferably 95 mol% or more of the unsaturated double bond based on the conjugated diene compound in the block copolymer may be hydrogenated. Only may be hydrogenated. When only a part is hydrogenated, the hydrogenation rate is preferably 10 mol% or more and less than 70 mol%, more preferably 15 mol% or more and less than 65 mol%, still more preferably 20 mol% or more. It is less than 60 mol%.

  The hydrogenation rate of the hydrogenated block copolymer can be measured by, for example, a nuclear magnetic resonance apparatus (NMR).

<Modification reaction>
In the present embodiment, after the above <polymerization reaction> or after <polymerization reaction> and <hydrogenation reaction>, a modification reaction for imparting a functional group to the block copolymer is performed as necessary. Also good.

  Examples of the modification method include a method in which a modifying agent that generates a functional group-containing atomic group is added to the living terminal of the block copolymer.

  Examples of functional group-containing atomic groups include, but are not limited to, hydroxyl groups, carbonyl groups, thiocarbonyl groups, acid halide groups, acid anhydride groups, ester groups, carboxyl groups, thiocarboxyl groups, and thiocarboxylic groups. Acid ester group, dithiocarboxylic acid ester group, carboxylic acid amide group, thiocarboxylic acid amide group, aldehyde group, thioaldehyde group, carboxylic acid ester group, amide group, sulfonic acid group, sulfonic acid ester group, phosphoric acid group, phosphoric acid Ester group, phosphite group, amino group, imino group, ethyleneimino group, nitrile group, pyridyl group, quinoline group, epoxy group, thioepoxy group, sulfide group, isocyanate group, thioisocyanate group, halogenated silyl group, silanol Group, alkoxysilyl group, tin halide group, alkoxy Tin group, phenyltin group, epithio group, atomic can be cited contains at least one functional group selected from the halogen group or the like.

  The modifying agent may be the coupling agent described above.

(Method to obtain crumb by treating block copolymer)
The method for producing a block copolymer crumb according to the present embodiment includes a step of extruding and drying the block copolymer or a hydrogenated product thereof using an extrusion dryer provided with a die having an opening at the outlet (“extrusion”). It is preferable to have a drying step.

From the viewpoint of shortening the dissolution time of the block copolymer crumb and heat discoloration resistance, the extrusion dryer preferably has a diameter of a circle circumscribing the die opening of 0.5 to 2.5 mm. The die shape factor obtained by dividing the total side length by the opening area is 0.4 to 4.0 mm ⁻¹ . If the diameter of the circle circumscribing the die opening is 2.5 mm or less and the die shape factor is 4.0 mm ⁻¹ or less, the dissolution time of the resulting block copolymer crumb can be shortened. On the other hand, if the die shape factor is 0.4 mm ⁻¹ or more, the block copolymer crumb has excellent heat discoloration resistance. Moreover, if the diameter of the circle circumscribing the die opening is 0.5 mm or more, the crumb shape becomes uniform and the melting time can be shortened.

  The shape of the die opening may be any shape as long as the die shape factor is in the above range, and examples include various shapes such as a round shape, a star shape, a cross shape, a Y shape, and a vertically long rectangle.

  The temperature at the outlet of the extrusion dryer is preferably 130 ° C. or higher. Moreover, in order to obtain a suitable bulk density, it is preferable that the temperature at the exit of an extrusion-type dryer shall be 130-180 degreeC. The temperature at the outlet of the extrusion dryer is more preferably 134 to 175 ° C, still more preferably 138 to 170 ° C. By setting the temperature within the above range, the crumb can be uniformly foamed, the drying process can be stably performed, the desired crumb shape can be obtained, and the block weight excellent in dissolution time and heat discoloration resistance can be obtained. Combined crumbs can be obtained.

  The water content of the block copolymer crumb (hereinafter also referred to as “first crumb”) at the outlet of the extruder is preferably 2.0% by mass or more. More preferably, it is 2.0-30 mass%, More preferably, it is 2.5-25 mass%, More preferably, it is 3-20 mass%. By setting the water content of the block copolymer crumb at 2.0% by mass or more at the outlet of the extruder, the crumb can be uniformly foamed. Or decomposition can be prevented. On the other hand, by setting the moisture content of the first crumb to 30% by mass or less, the moisture content of the block copolymer crumb (also referred to as “second crumb”) obtained by the drying step after the extrusion drying step described later is set. It becomes easy to control to less than 2.0 mass%. The water content of crumb can be measured by the method described in the examples.

  The die shape in the extrusion drying process is controlled, the temperature at the outlet of the extrusion dryer is 130 ° C. or more, and the moisture content of the block copolymer crumb (first crumb) at the outlet of the extrusion dryer is By setting the content to 2.0% by mass or more, the content of a component that passes through a 2.0 mm sieve of the block copolymer crumb and does not pass through a 0.6 mm sieve, The content of the component passing through the sieve, the specific surface area, the porosity, and the proportion of voids having a diameter of 100 μm or more can be set as desired.

Further, when the processing amount of the block copolymer is (F) and the opening area of the die is (S), the die flow rate (F / S) is 0.4 to 10 kg from the viewpoint of stability of the crumb shape. / (Hr · mm ² ) is preferable. More preferably, it is 0.5-8 kg / (hr * mm < ² >), More preferably, it is 0.6-7 kg / (hr * mm < ² >). The block copolymer throughput (F) (kg / hr) is the mass (kg) of the block copolymer obtained per hour, and the die opening area (S) (mm ² ) is The sum of the opening areas of all the dies including the case where there is a single die and the case where there are a plurality of dies is used.

  The extrusion dryer is not particularly limited, and for example, a uniaxial or biaxial screw expander dryer, a kneader dryer, or the like can be used. Each may be provided with a vent mechanism and a slit for dehydration according to the purpose of use. Extrusion drying may be one-stage drying, or may be multistage drying by combining a multistage extrusion dryer or a plurality of extrusion dryers.

  In the method for producing the block copolymer crumb of the present embodiment, the method for obtaining the crumb containing moisture (hereinafter also referred to as water-containing crumb) to be fed into the extrusion dryer is not particularly limited, For example, after obtaining a solution of the block copolymer or its hydrogenated product, the catalyst residue is removed if necessary, and then the block copolymer solution is put into hot water with stirring, and the solvent is removed by steam stripping. By removing, an aqueous slurry in which the block copolymer crumb is dispersed in water can be obtained, and stripping water can be separated from the aqueous slurry (hereinafter also referred to as “dehydration treatment”).

  In this embodiment, before the extrusion drying step, a solvent removal step for removing the solvent from the solution of the block copolymer or its hydrogenated product by steam stripping, and the block copolymer obtained by the solvent removal step Alternatively, it is preferable to have a step (dehydration step) of separating the stripping water from the aqueous slurry of the hydrogenated product to obtain a hydrated crumb of the block copolymer or the hydrogenated product. If there is a solvent removal step and a dehydration step before the extrusion drying step, the foaming property of the crumb is made uniform in the extrusion drying step, passes through a sieve having an opening of 2.0 mm, and has an opening of 0.6 mm. The content of the component that does not pass through the sieve, the content of the component that passes through the sieve having an aperture of 0.6 mm, the specific surface area, the porosity, the ratio of the voids having a diameter of 100 μm or more, the bulk density, and the aspect ratio are in the above-mentioned ranges. It becomes easy to obtain a block copolymer crumb.

  The treatment method in the steam stripping is not particularly limited and a conventionally known method can be adopted. For example, the block copolymer solution and the steam are added separately, and the block copolymer solution is added to the gas phase. By adding to the solvent, the solvent in the block copolymer solution and the water vapor rising from the liquid phase are brought into countercurrent contact in the gas phase, thereby reducing the amount of water vapor accompanying the solvent vapor and improving the steam intensity. Can be made.

  In the steam stripping, a crumbing agent may be used. As the crumbing agent, for example, an anionic surfactant, a cationic surfactant, or a nonionic surfactant is generally used. The crumbing agent is generally added in an amount of 0.1 to 3000 ppm with respect to the water in the stripping zone. In addition to these surfactants as crumbing agents, water-soluble salts of metals such as Li, Na, K, Mg, Ca, Al and Zn can also be used as crumb dispersion aids.

  The aqueous slurry can be dehydrated by, for example, a rotary screen, a vibrating screen, a centrifugal dehydrator, or the like.

  In addition, from the viewpoint of the appearance of the crumb after the drying treatment, after the extrusion drying step, the crumb (first crumb) obtained by extrusion drying is dried, and the moisture content of the crumb (second crumb) is increased. It is preferable that the process includes 0.01% by mass or more and less than 2.0% by mass.

The moisture content of the crumb after the drying treatment (second crumb) is preferably 0.01% by mass or more and less than 2.0% by mass, more preferably 0.02 to 1.5% by mass, More preferably, it is 0.03-1 mass%. By setting the water content to less than 2% by mass, it is possible to prevent appearance defects due to the occurrence of foaming or silver. On the other hand, by setting it as 0.01 mass% or more, generation | occurrence | production of the burn and gel in the crumb after a drying process can be suppressed. Examples of the drying treatment include hot air drying and vacuum drying, but hot air drying is preferable from the viewpoint of productivity.
The hot air dryer is not limited to the following, and examples thereof include a vibration transport dryer and a fluid dryer. The temperature of the hot air is preferably 70 to 150 ° C., more preferably 80 to 120 ° C., from the viewpoint of suppressing crumb deterioration and drying efficiency.

  The block copolymer crumb of the present embodiment can be shipped in a general packaging form such as a paper bag, a resin bag, a flexible container bag, etc., but for example, at the time of packaging, static electricity suppression treatment with plasma air, ionized air, etc. Can do.

  Hereinafter, the present embodiment will be described based on examples. Note that the present embodiment is not limited to the following examples.

The analysis of the sample in an Example was performed by the method shown below.
<(1) Bonded styrene content>
A chloroform solution of the block copolymer was prepared, and the amount of bound styrene (% by mass) was measured by detecting UV 254 nm absorption by the phenyl group of styrene using a spectrophotometer (manufactured by JASCO: V-550). .

<(2) Coupling rate>
A tetrahydrofuran solution of the block copolymer was prepared, and the chromatogram of the sample was measured using GPC (manufactured by Tosoh: HLC-8320) of polystyrene gel (manufactured by Showa Denko: Shodex), and calculated from the peak area ratio. .

<(3) Clam moisture content>
The block copolymer crumb (first crumb or second crumb) was heated with a halogen moisture meter at 150 ° C. for 8 minutes to determine its mass loss, and calculated according to the following formula.
Moisture content (mass%) = mass loss before and after heating (water content in crumb) / mass of hydrogenated block copolymer crumb before heating × 100

<(4) Melt viscosity>
The melt viscosity of the block copolymer was measured with a capillograph (Capillograph 1D type PM-C manufactured by Toyo Seiki Seisakusho). Measurement conditions were: capillary length: 10 mm, capillary diameter: 1.0 mm, furnace body diameter: 9.55 mm, load cell capacity: 20000 N.

<(5) Clam size>
Using a sieve shaker (Octagon Digital manufactured by Seishin Enterprise Co., Ltd.), a sieve with an aperture of 2.0 mm is stacked on a sieve with an aperture of 0.6 mm, and crumbs are put on the sieve with an aperture of 2.0 mm. Vibrate for 15 minutes, measure the amount of crumb remaining on each sieve, and the amount of crumb that has passed through, measure the proportion of crumbs that do not pass through a 2.0 mm sieve, pass through a 2.0 mm sieve, and open The proportion of crumbs that did not pass through a 0.6 mm sieve and the proportion of crumbs that passed through a 0.6 mm sieve were calculated. In Table 1, the ratio of crumbs that pass through a sieve having a mesh size of 2.0 mm and does not pass through a sieve having a mesh size of 0.6 mm is described as “a ratio of size 0.6 mm or more and less than 2.0 mm”. “The ratio of crumbs that passed through a sieve having an aperture of 0.6 mm” was described as “a ratio of size less than 0.6 mm”.

<(6) Specific surface area of crumb>
The adsorption isotherm by nitrogen of the block copolymer crumb was measured, and the specific surface area was determined by the BET multipoint method. The apparatus used was BELSORP-mini (manufactured by BEL Japan), and the measurement was performed at an adsorption temperature of 77K.

<(7) Crum porosity>
Using an X-ray CT (rigid high-resolution 3DX-ray microscope), a crumb shape was photographed with an X-ray target: Cu, an X-ray tube voltage of 40 kV, a tube current of 30 mA, and an imaging condition of 180 ° rotation. The obtained three-dimensional image was binarized into a structure and a space, and the void ratio and void size distribution were calculated from the binarized image.
Porosity = space volume in crumb volume / clam volume crumb volume = (clam structure volume) + (space volume in crumb volume)
For the void size, Thickness in the following document was obtained for the space portion, and the size distribution was calculated as the volume fraction. The size obtained by Thickness corresponds to the diameter of the space. The ratio of voids having a diameter of 100 μm or more to the total void volume was calculated. “A new method for the model independence assessment of thickness in three-dimensional images”. Hildebrand and P.M. Ruessegger, J. et al. of Microscopy, 185 (1996) 67-75.

<(8) Bulk density of crumb>
The block copolymer crumb was weighed in a 100 mL container, and the bulk density was calculated from the 100 mL mass.

<(9) Aspect ratio of crumb>
Thirty block copolymer crumbs were randomly extracted, the major axis and the minor axis were measured using a Keyence microscope VH8000C, and the ratio of crumbs having an aspect ratio of 1.5 to 5 was calculated in 30 crumbs. .

<(10) Clam dissolution time>
To a mixed solution of 3.0 g of toluene and 3.0 g of paraffinic process oil (Diana Process Oil PW90 manufactured by Idemitsu Petrochemical Co., Ltd.), 0.3 g of block copolymer crumb was added and shaken at room temperature for a predetermined time. After shaking, the solid component was taken out with filter paper, methanol was dropped to stop the progress of dissolution, and the solid component was weighed after drying at room temperature for 3 days.

<(11) Heat discoloration resistance of crumb>
The block copolymer crumb was kneaded at 160 ° C. and 100 rpm for 10 minutes using a Laboplast mill (Toyo Seiki Co., Ltd. 4M150), then compression molded at 120 ° C. to create a 2 mm pressure plate, and spectrophotometric colorimetry The b value was measured with a meter (SM-T45 manufactured by Suga Test Instruments Co., Ltd.).

<(12) Measurement of physical properties of asphalt composition>
1) Melt viscosity: measured with a Brookfield viscometer at 180 ° C.
2) Softening point, penetration, elongation: measured according to JIS-K-2207.
3) Toughness, tenacity: Measured according to the test method for pavement work (Japan Road Construction Industry Association).
4) Phase separation property: after standing at 160 ° C. for 3 days, the softening points of the upper and lower layers were measured, and the difference was defined as phase separation property.
5) Dissolution time: In the process of dissolving in asphalt, the composition was sampled every 30 minutes to measure the softening point, and the time when the softening point was stabilized was taken as the dissolution time.

<(13) Measurement of physical properties of adhesive composition>
1) Melt viscosity: The melt viscosity of the adhesive composition was measured with a Brookfield viscometer at the temperatures shown in Table 3.
2) Loop tack: Using a loop-shaped sample of 250 mm length × 15 mm width, measurement was made at a contact area to the polyethylene plate: 15 mm × 50 mm, a bonding time of 3 sec, and a bonding and peeling speed: 500 mm / min.
3) Peel: A sample having a width of 25 mm was attached to a polyethylene plate, and a 180 ° peeling force was measured at a peeling speed of 300 mm / min.
4) Creep: An adhesive tape was applied so that an area of 25 mm × 25 mm was in contact with the polyethylene plate, a load of 1 kg was applied at 40 ° C., and the time until the tape fell off was measured.
5) Dissolution time: In the process of preparing the adhesive composition, the composition was sampled every 15 minutes to measure the softening point, and the time when the softening point was stabilized was defined as the dissolution time.

(Production Example 1: Production method of block copolymer A)
Using a temperature-controllable autoclave with a stirrer and a jacket as a reactor, a cyclohexane solution containing 30 parts by mass of styrene and 0.14 parts by mass of tetrahydrofuran was prepared in a nitrogen gas atmosphere. After maintaining the internal temperature at 50 ° C., 0.15 parts by mass of n-butyllithium as a polymerization initiator was supplied to the reactor for polymerization.

  Next, 70 parts by mass of butadiene was supplied for polymerization, and after butadiene was almost completely polymerized, 0.12 parts by mass of dimethoxydimethylsilane was added as a coupling agent to cause a coupling reaction.

  After adding water as a reaction terminator to the obtained block copolymer solution in a 5-fold mol amount based on the amount of n-butyllithium used in the polymerization, n-octadecyl-3- (3,5 as a stabilizer was added. -Di-t-butyl-4-hydroxyphenyl) -propionate (product name Irganox 1076) with respect to 100 parts by mass of block copolymer, 0.13 parts by mass, 2,4-bis (octylthiomethyl) -6 -0.05 mass part of methylphenol (product name Irganox 1520) was added to 100 mass parts of the block copolymer.

The obtained block copolymer A had a styrene content of 30% by mass, a coupling rate of 69%, a melt viscosity at 150 ° C. and 100 s ⁻¹ of 5.0 × 10 ³ Pa · s as measured by a capillograph. .

(Production Example 2: Production method of block copolymer B)
Blocked in the same manner as in Production Example 1 except that 0.12 parts by mass of n-butyllithium as a polymerization initiator and 0.25 parts by mass of a bisphenol type epoxy compound (ZX) shown in Table 1 as a coupling agent were added. Copolymer B was produced. In addition, ZX used as a coupling agent is a compound in which a compound represented by the following formula (1) and a compound represented by the following formula (2) are mixed at a molar ratio of 1: 1.
The obtained block copolymer B had a styrene content of 30% by mass, a coupling rate of 74%, a melt viscosity at 150 ° C. and 100 s ⁻¹ of 8.0 × 10 ³ Pa · s as measured by a capillograph. .

(Production Example 3: Production method of block copolymer C)
Using a temperature-controllable autoclave with a stirrer and a jacket as a reactor, a cyclohexane solution of 40 parts by mass of styrene and 0.14 parts by mass of tetrahydrofuran from which impurities were removed was prepared in a nitrogen gas atmosphere. After maintaining the internal temperature at 50 ° C., 0.16 parts by mass of n-butyllithium as a polymerization initiator was supplied to the reactor for polymerization.

  Next, 72 parts by mass of butadiene was supplied for polymerization, and after butadiene was almost completely polymerized, 0.05 part by mass of dimethoxydimethylsilane was added as a coupling agent to cause a coupling reaction.

  After adding water as a reaction terminator to the obtained block copolymer solution in a 5-fold mol amount based on the amount of n-butyllithium used in the polymerization, n-octadecyl-3- (3,5 as a stabilizer was added. -Di-t-butyl-4-hydroxyphenyl) -propionate (product name Irganox 1076) is 0.1 parts by mass with respect to 100 parts by mass of the block copolymer, 2,4-bis (octylthiomethyl) -6 -0.04 mass part of methylphenol (product name Irganox 1520) was added with respect to 100 mass parts of block copolymers.

The resulting block copolymer C had a styrene content of 40% by mass, a coupling rate of 35%, a melt viscosity at 150 ° C. and 100 s ⁻¹ of 1.2 × 10 ³ Pa · s as measured by a capillograph. .

(Production Example 4: Production method of block copolymer D)
Using a temperature-controllable autoclave with a stirrer and a jacket as a reactor, a cyclohexane solution of 28 parts by mass of styrene and 0.14 parts by mass of tetrahydrofuran from which impurities were removed was prepared in a nitrogen gas atmosphere. After maintaining the internal temperature at 50 ° C., 0.09 parts by mass of n-butyllithium as a polymerization initiator was supplied to the reactor for polymerization.

  Next, 72 parts by mass of butadiene was supplied for polymerization, and after butadiene was almost completely polymerized, 0.05 part by mass of silicon tetrachloride was added as a coupling agent to cause a coupling reaction. After adding water as a reaction terminator to the obtained block copolymer solution in a 5-fold mol amount based on the amount of n-butyllithium used in the polymerization, n-octadecyl-3- (3,5 as a stabilizer was added. -Di-t-butyl-4-hydroxyphenyl) -propionate (product name Irganox 1076) with respect to 100 parts by mass of the block copolymer, 0.25 parts by mass, 2,4-bis (octylthiomethyl) -6 -Methylphenol (product name Irganox 1520) was added in an amount of 0.10 parts by mass with respect to 100 parts by mass of the block copolymer.

The resulting block copolymer D had a styrene content of 28% by mass, a coupling rate of 86%, a melt viscosity at 150 ° C. and 100 s ⁻¹ of 1.2 × 10 ⁴ Pa · s as measured by a capillograph. .

[Examples 1-7], [Comparative Examples 1-4]
The block copolymer solutions obtained in Production Examples 1 to 4 were each steam stripped at 95 ° C. for 1 hour. Steam stripping was carried out by adding isobutylene-maleic anhydride copolymer Na salt as a crumbing agent. The concentration of the block copolymer crumb in the obtained aqueous slurry was 5% by mass.
Next, the aqueous slurry containing the block copolymer crumb obtained above was dehydrated with a vibrating screen having an opening of 1 mm to obtain a hydrous crumb.
This water-containing crumb was put into a single screw type extruder having a round die at the outlet, and extruded at a screw rotation speed of about 120 rpm for drying treatment. Further, a 10-blade cutter was attached to the outlet of the extrusion dryer, and the crumb discharged from the die was cut so as to have an aspect ratio of 1.5 to 5 shown in Table 1. Table 1 shows the type of block copolymer used, the conditions of the die of the extrusion dryer, the operating conditions of the extrusion dryer, and the moisture content of the crumb (first crumb) at the outlet of the extrusion dryer.

  Thereafter, the block copolymer crumb obtained above was dried with hot air of about 90 ° C. using a vibration transport dryer.

  Finally obtained block copolymer crumb (second crumb) size, specific surface area, porosity, ratio of voids with a diameter of 100 μm or more to the total voids, bulk density, water content, and each embodiment Table 1 shows the dissolution time and heat discoloration (b value) of the block copolymer crumb (second crumb).

[Comparative Example 5]
The solution of the block copolymer A obtained by the said manufacture example 1 was dehydrated by the steam stripping and vibration screen by the method similar to Examples 1-5, and the water-containing crumb was obtained. Then, the drying process was performed with hot air of about 90 ° C. using a vibration transport dryer without passing through an extrusion dryer.
Table 1 shows the size, specific surface area, porosity, bulk density of the finally obtained block copolymer crumb, and dissolution time and heat discoloration (b value) as the effect of the block copolymer of this embodiment. Indicated.

Example 8
6 g of the block copolymer crumb obtained in Example 1 is added to 100 g of straight asphalt (Nippon Oil Co., Ltd. Store 60/80) and melt kneaded at 180 ° C. to prepare an asphalt composition. did. Table 2 shows the properties, dissolution time, and the like of the obtained asphalt composition.

[Comparative Example 6]
An asphalt composition was prepared in the same manner as in Example 8 except that the block copolymer crumb obtained in Comparative Example 2 was used instead of the block copolymer crumb in Example 1. Table 2 shows the properties, dissolution time, and the like of the obtained asphalt composition.

Example 9
100 g of the block copolymer crumb obtained in Example 4, 300 g of alicyclic saturated hydrocarbon resin Alcon M100 (manufactured by Arakawa Chemical Co., Ltd.) as a tackifier, and paraffinic process oil (Idemitsu Petroleum) as a softening agent 100 g of Diana Process Oil PW90 manufactured by Kagaku Co., Ltd. and 1 g of Sumilizer GM (manufactured by Sumitomo Chemical Co., Ltd.) as a heat stabilizer were mixed and melt-kneaded at 180 ° C. in a 1 liter container with a stirrer. A composition was obtained. The properties and dissolution time of the adhesive composition are shown in Table 3.

[Comparative Example 7]
The block copolymer crumb obtained in Example 4 was melt-kneaded with a twin-screw extruder and pelletized. The obtained pellet passes through a sieve having an opening of 2.0 mm and does not pass through a sieve having an opening of 0.6 mm, and 10.2% by mass of all the pellets. The passing component was 0.2% by mass of the whole pellet, the bulk density was 0.68 g / mL, the specific surface area was not analyzable (0.020 m ² / g or less), and the bulk density was 0.68 g / mL. . An adhesive composition was prepared by the same method as in Example 9 using the obtained pellets. The properties and dissolution time of the adhesive composition are shown in Table 3.

While the block copolymer crumbs of Examples 1 to 7 have a short dissolution time and low heat discoloration (b value), the block copolymer crumbs of Comparative Examples 1 to 5 have a long dissolution time. The block copolymer crumbs of 1, 3 and 5 also had high heat discoloration (b value).
When crumb was used as the material for the asphalt composition, the crumb of Example 1 could be dissolved in a shorter time than the crumb of Comparative Example 2. Further, in the production of the adhesive composition, when the crumb of Example 4 was used, it could be dissolved in a shorter time than when pellets prepared by melt extrusion of the crumb were used.

  The block copolymer crumb obtained by the method for producing a block copolymer crumb of the present invention is particularly preferably used in the fields of asphalt modifiers, adhesives and the like, and further in the footwear field, plastic modifier field, It can be used in fields such as household products, home appliances, industrial parts, medical materials, and toy materials.

Claims (8)

A block copolymer crumb containing a block copolymer containing a vinyl aromatic hydrocarbon unit and a conjugated diene unit, or a hydrogenated product thereof and satisfying the following (1) to (4).
(1) The melt viscosity at 150 ° C. and 100 s ⁻¹ measured by a capillograph is 1.0 × 1
0 ^{3 to} 1.0 × 10 ⁴ Pa · s,
(2) The component that passes through a sieve having an opening of 2.0 mm and does not pass through a sieve having an opening of 0.6 mm is 50% by mass or more of the total crumb, and further passes through a sieve having an opening of 0.6 mm. Ingredients are 10% by weight or less of the total crumb,
(3) Specific surface area is 0.05-0.30 m ² / g,
(4) The void ratio is 0.01 to 0.20, and voids having a diameter of 100 μm or more occupy 0.2 to 15% by volume of the total voids. The block copolymer crumb according to claim 1, having a bulk density of 0.25 to 0.70 g / mL. The block copolymer crumb according to claim 1 or 2, wherein the component having an aspect ratio of 1.5 to 5.0 is 50% by mass or more based on the total mass of the crumb. Having a step of producing a crumb by extrusion drying the block copolymer or its hydrogenated product using an extrusion dryer provided with a die having an opening at the outlet;
The diameter of the circle circumscribing the opening of the die is 0.5 to 2.5 mm,
A die shape factor obtained by dividing the total side length of the opening of the die by the opening area of the die is 0.4 to 4.0 mm ⁻¹ ;
2. The block copolymer crumb according to claim 1, wherein the temperature at the outlet of the extruder is 130 ° C. or higher, and the moisture content of the crumb at the outlet of the extruder is 2.0 mass% or higher. Manufacturing method. The method for producing a block copolymer crumb according to claim 4, wherein a temperature at an outlet of the extruder is 130 to 180 ° C. in the extrusion drying step. In the extrusion drying step, the moisture content of the crumb at the outlet of the extrusion dryer is 2.0-30.
The manufacturing method of the block copolymer crumb of Claim 4 or 5 which is the mass%. Before the extrusion drying step,
Removing the solvent from the solution of the block copolymer or its hydrogenated product by steam stripping; and
Separating the stripping water from the aqueous slurry of the block copolymer or hydrogenated product obtained by the solvent removal step to obtain a hydrous crumb of the block copolymer or hydrogenated product;
The method for producing a block copolymer crumb according to any one of claims 4 to 6, comprising: After the extrusion drying step,
The block copolymer according to any one of claims 4 to 7, comprising a step of drying the crumb obtained by extrusion drying to obtain a crumb having a water content of 0.01% by mass or more and less than 2.0% by mass. Clam manufacturing method.