JP2023158643A - Crumb of block copolymer or hydrogenated product thereof and asphalt composition - Google Patents

Abstract

To provide a block copolymer crumb which is suppressed in blocking and is excellent in transportation efficiency while being excellent in solubility and oil absorption.SOLUTION: Provided is a crumb of a block copolymer or its hydrogenated product, including a polymer block A mainly containing a vinyl aromatic monomer unit, a polymer block B mainly containing a conjugated diene monomer unit and/or a polymer block C including a vinyl aromatic monomer unit and a conjugated diene monomer unit, in which the following (1) to (6) are satisfied: (1) an average weight value per crumb is 0.0080 to 0.0500 g, (2) an average aspect ratio value per crumb is 1.00 to 3.50, (3) an average volume value per crumb is 18.0 to 110 mm3, (4) an average specific gravity value per crumb is 2.0×10-4 to 1.0×10-3 g/mm3, (5) a component passing through a sieve with an aperture of 3.35 mm corresponds to 41% by mass or more of the entire crumb, and (6) a melt flow rate of the crumb is 0.3 g/10 min or less in a G condition.SELECTED DRAWING: None

Description

The present invention relates to a crumb of a block copolymer or its hydrogenated product, and an asphalt composition.

Conventionally, block copolymers consisting of a polymer block mainly composed of a conjugated diene monomer and a polymer block mainly composed of a vinyl aromatic monomer, or their hydrogenated products, have not been vulcanized. It has the same elasticity as vulcanized natural rubber or synthetic rubber at room temperature, and has excellent processability at high temperatures similar to that of thermoplastic resin, making it suitable for use in footwear, plastic modifiers, and asphalt modifiers. It is widely used in fields such as raw materials and adhesives, household products, packaging materials for home appliances and industrial parts, toys, etc.

The above-mentioned block copolymers or hydrogenated products thereof are commercially available in various forms such as pellets and crumbs, among which crumb-like block copolymers or hydrogenated products thereof are porous and have excellent solubility. For example, it is suitably used in fields such as asphalt modifiers and adhesives.

Many proposals have been made in the past regarding methods for obtaining crumbs of block copolymers or their hydrogenated products (hereinafter also referred to as "block copolymer crumbs").

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

In addition, as a method to improve the oil absorption of high molecular weight hydrogenated block copolymer crumb, we adjusted the operating temperature of the extruder for dehydrating the hydrogenated block copolymer crumb and the water content of the slurry before feeding it into the extruder. A dehydration/drying method using an extrusion dehydrator (see, for example, Patent Document 3), and a method of drying hydrogenated block copolymer crumb using a hot air dryer under specific temperature conditions (for example, Patent Documents 4 and 5) ) has been proposed.

Block copolymer compositions are known as asphalt modifiers that have bulk density, particle size distribution, and pore volume within a specific range, have good solubility in asphalt, and have excellent subsequent processability. (For example, see Patent Document 6).

Patent No. 3310536 Patent No. 6345703 Patent No. 5591346 Patent No. 4798333 Japanese Patent Application Publication No. 11-315187 Patent No. 6483529

In order to improve the solubility and oil absorption of block copolymer crumbs, various studies have been conducted, mainly on methods to increase the specific surface area. However, there is no mention or implementation of this issue, although the deterioration of transportation efficiency and the deterioration of transportation efficiency will become evident. That is, there is still a need for a block copolymer crumb that has excellent solubility and oil absorption, suppresses blocking, and has excellent transport efficiency.

In order to solve the above problems, the present inventors have conducted extensive studies on the shape of the block copolymer crumb, and as a result, they have found that the above problems can be solved by forming it into a specific shape, and in order to complete the present invention. It's arrived.

The present invention includes the following embodiments.
[1]
A polymer block A mainly composed of vinyl aromatic monomer units,
A polymer block B mainly consisting of conjugated diene monomer units and/or a polymer block C consisting of vinyl aromatic monomer units and conjugated diene monomer units,
A crumb of a block copolymer or its hydrogenated product having
A crumb that satisfies (1) to (6) below.
(1) The average weight per crumb is 0.0080 to 0.0500 g,
(2) The average value of the aspect ratio per crumb is 1.00 to 3.50,
(3) The average volume per crumb is 18.0 to 110 mm ³ ,
(4) The average value of specific gravity per crumb is 2.0×10 ⁻⁴ to 1.0×10 ⁻³ g/mm ³ ,
(5) The components that pass through a sieve with an opening of 3.35 mm are 41% by mass or more of the total crumb,
(6) The crumb melt flow rate is 0.3 g/10 minutes or less under G conditions.
[2]
The crumb according to [1], wherein the average weight per crumb is 0.0100 to 0.0300 g.
[3]
The crumb according to [1] or [2], wherein the average weight per crumb is 0.0120 to 0.0200 g.
[4]
The crumb according to any one of [1] to [3], wherein the average volume per crumb is 20.0 to 90.0 mm ³ .
[5]
The crumb according to any one of [1] to [4], wherein the average volume per crumb is 20.0 to 80.0 mm ³ .
[6]
The crumb according to any one of [1] to [5], wherein the average value of specific gravity per crumb is 2.0×10 ⁻⁴ to 5.0×10 ⁻⁴ g/mm ³ .
[7]
The crumb according to any one of [1] to [6], wherein the average value of the aspect ratio per crumb is 1.00 to 1.60.
[8]
The content of vinyl aromatic monomer units in the block copolymer or hydrogenated product thereof is 20 to 50% by mass,
The vinyl bond amount of the conjugated diene monomer unit is 5 to 50 mol%,
The crumb according to any one of [1] to [7], having a weight average molecular weight of 100,000 to 500,000.
[9]
0.5 to 50 parts by mass of crumb according to any one of [1] to [8],
100 parts by mass of asphalt,
An asphalt composition containing.

According to the present invention, it is possible to provide a block copolymer crumb that has good oil absorption and solubility, excellent blocking resistance, and excellent transport efficiency. (Hereinafter, being able to dissolve a non-aromatic softener in asphalt in a short time is referred to as having excellent solubility, and allowing a non-aromatic softener to absorb a large amount of oil in a short time is also simply being referred to as having excellent oil absorption.)

Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail. The present invention is not limited to the following embodiment, and can be implemented with various modifications within the scope of the gist.

The block copolymer crumb of the present invention has a polymer block A mainly composed of vinyl aromatic monomer units, and a polymer block B mainly composed of conjugated diene monomer units and/or a vinyl aromatic monomer unit. It has a polymer block C consisting of a mer unit and a conjugated diene monomer unit.

Note that the term "vinyl aromatic monomer unit" refers to a structure corresponding to one vinyl aromatic hydrocarbon compound produced as a result of polymerizing vinyl aromatic hydrocarbon compounds. Examples of vinyl aromatic hydrocarbon compounds include, but are not limited to, alkylstyrenes such as styrene, α-methylstyrene, p-methylstyrene, and p-tert-butylstyrene; alkoxystyrenes such as p-methoxystyrene; Examples include naphthalene. Among these, styrene is preferred as the vinyl aromatic hydrocarbon. Vinyl aromatic hydrocarbon compounds may be used alone or in combination of two or more.

"Conjugated diene monomer unit" refers to a structure resulting from polymerization of one conjugated diene compound. The conjugated diene compound is not particularly limited as long as it is a diolefin having a conjugated double bond, but examples include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), and 2,3-dimethyl-1. , 3-butadiene, 1,3-pentadiene, 1,3-hexadiene and the like. Among these, 1,3-butadiene and isoprene are preferred as the conjugated diene compound due to their easy availability. Further, it is more preferable to use 1,3-butadiene because it tends to have excellent heat aging resistance and light resistance. The conjugated diene compounds may be used alone or in combination of two or more.

(Block A)
"Polymer block A mainly composed of vinyl aromatic monomer units" means that the ratio of vinyl aromatic monomer units to the entire polymer block A is more than 90% by mass, preferably 95% by mass or more. It refers to a polymer block having a content of 98% by mass or more, more preferably 98% by mass or more.

(Block B)
"Polymer block B mainly composed of conjugated diene monomer units" means that the ratio of conjugated diene monomer units to the entire polymer block B is more than 90% by mass, preferably 95% by mass or more, More preferably, it refers to a polymer block having a content of 98% by mass or more.

(Block C)
"Polymer block C consisting of vinyl aromatic monomer units and conjugated diene monomer units" refers to the mass ratio of conjugated diene monomer units to vinyl aromatic monomer units (conjugated Diene monomer unit: vinyl aromatic monomer unit) is in the range of 10:90 to 90:10. The ratio is preferably 10:90 to 85:15, more preferably 10:90 to 80:20. Further, the vinyl aromatic hydrocarbon C in the copolymer block may be distributed uniformly or may be distributed in a tapered shape. Further, in the copolymer block C portion, a plurality of portions in which vinyl aromatic hydrocarbons are uniformly distributed and/or a plurality of portions in which vinyl aromatic hydrocarbons are distributed in a tapered manner may coexist. Furthermore, in the copolymer block C portion, a plurality of portions having different vinyl aromatic hydrocarbon contents may coexist.

The block rate of the vinyl aromatic hydrocarbon incorporated into the block copolymer was measured by a method of oxidative decomposition of the block copolymer with tert-butyl hydroperoxide using osmium tetroxide as a catalyst (I.M. A vinyl aromatic hydrocarbon polymer block component obtained by the method described in KOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946) (the combined component is excluded) can be calculated from the following formula.
Block rate of vinyl aromatic hydrocarbon (mass%)
= (mass of vinyl aromatic hydrocarbon polymer block in block copolymer/mass of total vinyl aromatic hydrocarbon in block copolymer) x 100

The arrangement of polymer block A and polymer block B or C is not particularly defined, but linear structures ABA, ACA, BAABA, BAAC- A, A-B-C-A, and coupling structures such as (A-B-)nX, (A-C-)nX, (B-A-B)nX, (B-A-C)nX, etc. It is preferable for the molecule to contain a structure having a plurality of A blocks, from the viewpoint of sufficiently exhibiting the rubber elasticity as an elastomer. (In the above formula, each A independently represents a polymer block A, each B independently represents a polymer block B, and each C independently represents a polymer block C. Each n is Each X independently represents an integer of 2 or more, and each X independently represents a residue of a coupling agent.)

(Content of vinyl aromatic monomer units)
The total amount of vinyl aromatic monomer units contained in the block copolymer of this embodiment is preferably 20 to 50% by mass. When the content of the vinyl aromatic monomer unit is within the above range, the softening point of the asphalt composition tends to be excellent when crumb is blended into the asphalt composition. The content of vinyl aromatic monomer units in the block copolymer composition can be controlled by adjusting the amount of vinyl aromatic monomer added in the polymerization reaction of the block copolymer of this embodiment. can. Further, the content of the vinyl aromatic monomer unit in the polymer composition can be measured by the method described in the Examples below.

(vinyl bond amount)
The microstructure (ratio of cis, trans, and vinyl) of the conjugated diene moiety in the block copolymer can be controlled by using a polar compound, etc., which will be described later. When 1,3-butadiene is used as the conjugated diene, the amount of 1,2-vinyl bonds is preferably 5 to 90 mol%, more preferably 5 to 80 mol%, from the viewpoint of heat resistance and flexibility of the block copolymer. %, and from the viewpoint of the balance between softening point and melt viscosity in the asphalt composition, it is preferably 5 to 50 mol%.

Note that when isoprene is used as the conjugated diene or when 1,3-butadiene and isoprene are used together, the total amount of 1,2-vinyl bonds and 3,4-vinyl bonds is defined as the amount of vinyl bonds. The amount of vinyl bonds can be measured by the method described in Examples below.

(Hydrogenation rate of block copolymer)
When the block copolymer is a hydrogenated product, the total hydrogenation rate of unsaturated double bonds based on the conjugated diene compound can be arbitrarily selected depending on the purpose and is not particularly limited. For example, when heat resistance is required during processing, molding, or use, the hydrogenation rate of unsaturated double bonds based on the conjugated diene compound in the block copolymer is preferably 70 mol% or more, more preferably 80 mol% or more. Preferably, it is more preferably 90 mol% or more. Further, only a portion may be hydrogenated, for example, for the purpose of controlling compatibility with other asphalts and controlling the crosslinking rate. When only a portion is hydrogenated, it is recommended that the hydrogenation rate be 10 mol% or more and less than 80 mol%, or 15 mol% or more and less than 75 mol%, and optionally 20 mol% or more and less than 70 mol%. Furthermore, in the hydrogenated block copolymer, the hydrogenation rate of the vinyl bonds based on the conjugated diene before hydrogenation is preferably 85 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% or more. Recommended for obtaining compositions with excellent thermal stability.

Here, the hydrogenation rate of vinyl bonds refers to the proportion of hydrogenated vinyl bonds among the vinyl bonds based on the conjugated diene before hydrogenation incorporated into the block copolymer.
The hydrogenation rate of the aromatic double bond based on the vinyl aromatic hydrocarbon in the block copolymer is not particularly limited, but is preferably 50 mol% or less, more preferably 30 mol% or less, and even more preferably 20 mol%. The following is recommended: The hydrogenation rate can be determined by nuclear magnetic resonance (NMR).

(Molecular weight of block copolymer)
Although the molecular weight of the block copolymer is not particularly limited, the Mw is preferably in the range of 100,000 to 500,000 since it is suitably used as an asphalt composition. A value of 100,000 or more is preferable from the viewpoint of easily achieving a high softening point when forming an asphalt composition and reducing the amount of block copolymer added, that is, from the viewpoint of shortening production time. Setting it to 500,000 or less is practical and preferable because the melt viscosity of the asphalt composition is not too high.

(MFR of block copolymer)
The MFR of the block copolymer of this embodiment is less than 0.3 g/10 minutes under the conditions of a test temperature of 200° C. and a test load of 5 kgf. By setting the MFR to less than 0.3 g/10 minutes, it is easy to achieve a high softening point when used as an asphalt composition.

(Method for producing block copolymer)
Methods for producing block copolymers include, for example, Japanese Patent Publication No. 36-19286, Japanese Patent Publication No. 43-17979, Japanese Patent Publication No. 46-32415, Japanese Patent Publication No. 49-36957, and Japanese Patent Publication No. 48-2423. , Japanese Patent Publication No. 48-4106, Japanese Patent Publication No. 51-49567, Japanese Patent Application Laid-Open No. 59-166518, and the like.

Solvents used in the production of block copolymers include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane, and isooctane, and fatty acids such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane. Hydrocarbon solvents such as cyclic hydrocarbons or aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene can be used. These may be used not only alone but also in combination of two or more.

The organolithium compounds used in the production of block copolymers are compounds in which one or more lithium atoms are bonded in the molecule, such as ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium. Examples include lithium, tert-butyl lithium, hexamethylene dilithium, butadienyl dilithium, and isoprenyl dilithium.

Polar compounds and randomizing agents are used for purposes such as adjusting the polymerization rate during block copolymer production, changing the microstructure of the polymerized conjugated diene moiety, and adjusting the reactivity ratio between the conjugated diene and the vinyl aromatic hydrocarbon. can be used. Examples of polar compounds and randomizing agents include ethers, amines, thioethers, phosphoramides, potassium salts or sodium salts of alkylbenzenesulfonic acids, potassium or sodium alkoxides, and the like. Examples of suitable ethers are dimethyl ether, diethyl ether, diphenyl ether, tetrahydrofuran, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dipropylene glycol dimethyl ether, ditetrahydrofurylpropane (DTHFP), ethyltetrahydrofurfuryl ether. As amines, tertiary amines, trimethylamine, triethylamine, tetramethylethylenediamine, and other cyclic tertiary amines can also be used. Examples of phosphine and phosphoramide include triphenylphosphine and hexamethylphosphoramide.

The polymerization temperature when producing the block copolymer is preferably -10 to 150°C, more preferably 30 to 120°C. The time required for polymerization varies depending on the conditions, but is preferably within 48 hours, particularly preferably 0.5 to 10 hours. Further, the atmosphere of the polymerization system is preferably an inert gas atmosphere such as nitrogen gas. The polymerization pressure is not particularly limited as long as it is within a pressure range sufficient to maintain the monomer and solvent in a liquid phase within the above polymerization temperature range. Furthermore, it is preferable to prevent impurities such as water, oxygen, carbon dioxide gas, etc. that would inactivate the catalyst and living polymer from entering the polymerization system.

The block copolymer may be hydrogenated. Hydrogenation catalysts are not particularly limited and are conventionally known (1) Supported heterogeneous hydrogenation in which metals such as Ni, Pt, Pd, Ru are supported on carbon, silica, alumina, diatomaceous earth, etc. catalyst, (2) a so-called Ziegler 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 organoaluminum, (3) Ti, Ru, A homogeneous hydrogenation catalyst such as a so-called organometallic complex such as an organometallic compound such as Rh or Zr is used. Specific hydrogenation catalysts include Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-37970, Japanese Patent Publication No. 1-53851, and Japanese Patent Publication No. 1-53851. The hydrogenation catalyst described in Hei 2-9041 can be used. Preferred hydrogenation catalysts include titanocene compounds and/or mixtures with reducing organometallic compounds.

As the titanocene compound, the compounds described in JP-A-8-109219 can be used, and specific examples include (substituted) titanium dichloride, monopentamethylcyclopentadienyl titanium trichloride, etc. Examples include compounds having at least one ligand having a cyclopentadienyl 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 at a temperature range of 0 to 200°C, more preferably 30 to 150°C. The pressure of hydrogen used in 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. Further, the hydrogenation reaction time is preferably 3 minutes to 10 hours, more preferably 10 minutes to 5 hours. The hydrogenation reaction can be a batch process, a continuous process, or a combination thereof.

<Block copolymer or its hydrogenated crumb>
The block copolymer or its hydrogenated product obtained by the method described above is recovered as block copolymer crumb through the steps described below.

The block copolymer crumb of this embodiment has specific weight, aspect ratio, volume, and specific gravity. Note that in this specification, "crumb" is one of the solid forms of a polymer, and is distinguished from pellets and powder.

Crumb refers to a block copolymer with a small particle size that is extruded, dried and cut in an unmolten or partially molten state, and refers to a block copolymer that is partially foamed and has a specific surface area of 0.1 mm. Defined as ² /g or more.

<Crum shape>
The shape of the crumb of this embodiment will be explained below. In addition, the aspect ratio, volume, weight, specific gravity, and particle size of the crumb, which will be described below, can all be controlled by the conditions of the dehydration treatment and drying treatment in step 2, especially in the step of recovering the block copolymer crumb, which will be described later. . Specifically, the short side length can be controlled by the shape of the hole in the die, and the long side length can be controlled by the crumb feed flow rate, the total area of the hole, that is, the total opening area, the number of cutter blades, and the rotation speed. Note that the width and length values increase due to foaming during extrusion, but the foaming ratio can be controlled by the specific energy of the extruder.

(Aspect ratio per crumb)
The average value of the aspect ratio per crumb in this embodiment is 1.00 to 3.50. More preferably 1.00 to 3.00, still more preferably 1.00 to 1.60.

The aspect ratio can be defined as the ratio of the longest side length to the shortest side length of one crumb, and can be measured and calculated by the method described in Examples below.

The shape of the die hole is circular with a diameter of 1 to 4 mm, the crumb feed flow rate is 2 to 4 t/h, the total area of the die opening is 1500 to 8000 mm ² , the number of cutter blades is 5 to 12, and the cutter It is possible to control the aspect ratio by keeping the rotational speed within the range of 500 to 3000 rpm and the specific energy within the range of 0.12 kWh/kg or less. In particular, it is preferable in practical use to make adjustments by controlling the number of cutter blades and the number of rotations. The number of cutter blades×number of rotations is preferably in the range of 4,500 to 36,000 rpm, and more preferably in the range of 10,000 to 22,000 rpm.

When the aspect ratio is larger than 3.5, that is, when the crumb shape is "long", the crumbs become entangled with each other, deteriorating blocking resistance, and voids are likely to be formed during filling, resulting in a decrease in bulk density, which reduces transportability. Efficiency decreases.

(Volume per crumb)
The average value of the volume per crumb in this embodiment is 18.0 to 110 mm ³ . The lower limit is preferably 20.0 mm ³ or more, more preferably 25.0 mm ³ or more, and even more preferably 28.0 mm ³ or more. The upper limit is preferably 90.0 mm ³ or less, more preferably 80.0 mm ³ or less, even more preferably 70.0 mm ³ or less, particularly preferably 60.0 mm ³ or less.

The volume of the block copolymer crumb can be calculated from the shortest side length and longest side length of the crumb by the method described in Examples below.

The shape of the die hole is circular with a diameter of 1 to 4 mm, the crumb feed flow rate is 2 to 4 t/h, the total area of the die opening is 1500 to 8000 mm ² , the number of cutter blades is 5 to 12, and the cutter It is possible to control the volume by keeping the rotation speed within the range of 500 to 3000 rpm and the specific energy within the range of 0.12 kWh/kg or less. In particular, from the viewpoint of controlling the volume while achieving the above-mentioned aspect ratio, it is preferable to adjust the number of cutter blades x number of rotations in the range of 4500 to 36000 rpm and by controlling the diameter of the die hole. It is particularly preferable that the hole in the die has a circular shape with a diameter of 2 to 3 mm.

When the average value of the volume is 20.0 mm ³ or more, the contact area between the crumbs is small and the blocking resistance is good. Furthermore, due to the suppression of blocking, the apparent volume is relatively small, and the solubility in asphalt tends to be high. When the volume is larger than 110 mm ³ , in addition to being poor in asphalt solubility and oil absorption, voids are likely to be formed during filling, resulting in a decrease in bulk density, that is, a decrease in transport efficiency.

(Weight per crumb)
The average weight per crumb in this embodiment is 0.0080 to 0.0500 g. Preferably it is 0.0100 or more, more preferably 0.0120. The upper limit is preferably 0.0400 g, more preferably 0.0300 or less, still more preferably 0.0200 g or less. The weight of the block copolymer crumb can be measured and calculated by the method described in Examples below. The shape of the die hole is circular with a diameter of 1 to 4 mm, the crumb feed flow rate is 2 to 4 t/h, the total area of the die opening is 1500 to 8000 mm ² , the number of cutter blades is 5 to 12, and the cutter It is possible to control the weight by keeping the rotation speed within the range of 500 to 3000 rpm and the specific energy within the range of 0.12 kWh/kg or less. In particular, from the viewpoint of controlling the weight while achieving the above-mentioned aspect ratio and volume, the number of cutter blades x rotation speed = 4,500 to 36,000 rpm, and the shape of the die hole is circular with a diameter of 2 to 3 mm. It is preferable that the specific energy be adjusted by controlling the specific energy. The specific energy is more preferably 0.10 kWh/kg or less, particularly preferably 0.09 kWh/kg.

When the weight is 0.0080 g or more, the bulk density is sufficient, that is, the transportation efficiency is good. When the weight is 0.0500 g or less, asphalt solubility and oil absorption are good when blended into an asphalt composition.

(Specific gravity per crumb)
The specific gravity of each crumb in this embodiment is 2.0×10 ⁻⁴ to 1.0×10 ⁻³ g/mm ³ , and 2.0×10 ⁻⁴ to 5.0×10 ⁻⁴ g/mm 3 . mm ³ is more preferred.

The specific gravity of the block copolymer crumb is calculated by dividing the average weight of each crumb obtained by the method described above by the average volume of each crumb obtained by the method described above. be able to. The shape of the die hole is circular with a diameter of 1 to 4 mm, the crumb feed flow rate is 2 to 4 t/h, the total area of the die opening is 1500 to 8000 mm ² , the number of cutter blades is 5 to 12, and the cutter It is possible to control the specific gravity by keeping the rotational speed within the range of 500 to 3000 rpm and the specific energy within the range of 0.12 kWh/kg or less. In particular, from the viewpoint of controlling the specific gravity while achieving the above-mentioned aspect ratio and volume, the number of cutter blades x number of revolutions should be in the range of 4,500 to 36,000 rpm, and the shape of the die hole should be circular with a diameter of 2 to 3 mm. It is preferable that the specific energy be adjusted by controlling the specific energy. The specific energy is more preferably 0.10 kWh/kg or less, particularly preferably 0.09 kWh/kg.

When the specific gravity is 2.0×10 ⁻⁴ or more, the bulk density is sufficient, that is, the transportation efficiency tends to be high, and when the specific gravity is 1.0×10 ⁻³ g/mm ³ or less, asphalt Good asphalt solubility and oil absorption when used in compositions.

(Particle size of crumb)
Further, the block copolymer crumb of the present embodiment contains a component that passes through a sieve with an opening of 3.35 mm at 41% by mass or more of the total crumb. The content is more preferably 80% by mass or more, and still more preferably 90% by mass or more. Note that, here, the ratio of components passing through a sieve with an opening of 3.35 mm is expressed as particle size.

The shape of the die hole is circular with a diameter of 1 to 4 mm, the crumb feed flow rate is 2 to 4 t/h, the total area of the die opening is 1500 to 8000 mm ² , the number of cutter blades is 5 to 12, and the cutter It is possible to control the particle size of the crumb by setting the rotation speed to 500 to 3000 rpm and the specific energy to 0.12 kWh/kg or less. In particular, it is preferable to adjust by controlling the diameter of the hole in the die. It is particularly preferable that the hole in the die has a circular shape with a diameter of 2 to 3 mm. If the amount of components passing through a sieve with an opening of 3.35 mm is less than 41% by mass, the transport efficiency will be significantly reduced, and blocking resistance, asphalt solubility, and oil absorption will deteriorate.

<Process of collecting crumbs>
In order to remove catalyst residues from the block copolymer solution as necessary, the block copolymer solution is poured into boiling water with stirring, and the solvent is removed by steam stripping to form block copolymer crumbs. An aqueous slurry in which the precursor is dispersed in water is obtained.

The processing method for steam stripping is not particularly limited, and conventionally known methods can be used.

A crumbling agent may be used during steam stripping, and anionic surfactants, cationic surfactants, and nonionic surfactants are commonly used as crumbling agents.

The surfactant as the crumbling agent is generally added in an amount of 0.1 to 3000 ppm to the water in the stripping zone. In addition to these surfactants, 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 in which the block copolymer crumb precursor is dispersed in water obtained by the steam stripping process is dehydrated and dried through the following steps to recover the block copolymer crumb of this embodiment. be able to.

The block copolymer crumb recovery process is not limited to the following, but may be carried out by, for example, performing <Step 1> dehydration treatment, <Step 2> dehydration treatment and drying treatment, and <Step 3> drying treatment, which will be described later. I can do it. Note that in <Step 2>, the dehydration treatment and the drying treatment may be performed using separate devices, and a so-called integrated type having a structure that includes a dehydration treatment means and a drying treatment means and communicates with each other. It may also be carried out using an extrusion dryer.

<Step 1>
An aqueous slurry in which a block copolymer crumb precursor is dispersed in water is dehydrated, and the total weight of the polymer component is that the water content exceeds 60 mass % and is 80 mass % or less and does not pass through a sieve with a mesh size of 1.5 mm. A polymer is obtained which is 80% by mass or more of the coalescence. For example, sifting an aqueous slurry through a vibrating screen creates a sound that dehydrates the slurry and adjusts its moisture content. By setting the temperature of the aqueous slurry at this time to 95°C or less, the shear heat generation and die temperature when processing the crumbs in the drying extruder in the next <Step 2> are reduced, and the energy required for dehydration and drying is reduced. It becomes easier to obtain the desired crumb shape.

The dehydration treatment in <Step 1> can be performed using, for example, a rotary screen, a vibrating screen, a centrifugal dehydrator, or the like.

By setting the moisture content of the crumb obtained in step 1 to 60% by mass or more, it becomes easier to adjust the specific energy in step 2, and by setting the moisture content to 80% by mass or less, residual moisture at the extruder outlet can be reduced. is suppressed, and the final crumb shape tends to be stable.

Furthermore, by setting the crumb component that does not pass through a sieve with an opening of 1.5 mm to 80% by mass or more of the total crumb, the dehydration and drying treatment in <Step 2> described below can be performed stably, and the desired crumb can be obtained. A block copolymer with specific shape (weight, aspect ratio, volume) is obtained.

<Step 2>
The crumbs that have been dehydrated in <Step 1> and have a predetermined moisture content are subjected to dehydration treatment and drying treatment in <Step 2> to obtain crumbs with a moisture content of 3 to 30% by mass. 3>.

The moisture content of the crumb after passing through <Step 2> is preferably 3 to 25% by mass, more preferably 3 to 20% by mass.

The dehydration treatment and drying treatment may be performed using independent devices, but it is also possible to use a so-called integrated extrusion dryer that is equipped with a dehydration treatment means and a drying treatment means, and has a structure in which these are in communication. You can go.

The extrusion dryer is a device that performs dehydration processing and drying processing, and is equipped with a dehydration processing means and a drying processing means. A kneader type dryer, a screw type expander type dryer, etc. are used. Particularly preferred is a structure that is equipped with a multi-screw extruder such as a single screw or twin screw extruder as a dehydration treatment means and a screw dryer as a drying treatment means from the viewpoint of dewatering efficiency and workability.

In order to gently control the dehydration of crumbs, a combination of a single screw extruder and a screw dryer is particularly preferred. In addition, when the feed flow rate of the crumb obtained in step 1 to the extrusion type dryer is F "t/h", the rotation speed R of the extrusion type dryer is (F/R) from 0.5 to It is preferable to set it in the range of 1.5 t/rph. More preferably 0.6 to 1.4 t/rph, still more preferably 0.8 to 1.2 t/rph. Being in this range is stable. In other words, it is possible to control the moisture content of the crumb at the outlet of the extrusion dryer to 3 to 25% by mass.

The crumb shape (aspect ratio, volume, weight, specific gravity, particle size) of this embodiment can be controlled by setting various conditions of the extrusion dryer.

The extrusion dryer outlet is equipped with a plurality of dies having a plurality of holes, and crumbs are continuously discharged from the holes. The continuously discharged crumbs are cut by a rotary cutter blade adjacent to the extruder dryer outlet to determine their shape. In addition, the crumb is foamed due to the pressure being released at the die exit.

From these viewpoints, the width is controlled by the shape of the hole, the length is controlled by the so-called linear velocity, which is calculated by dividing the feed flow rate by the total opening area, the number of cutter blades, and the rotation speed, and the foaming ratio is controlled by the specific energy. That is, it is understood that the power value of the entire extrusion dryer per unit weight of crumb can be used as an index.

Here, the following conditions are preferable for obtaining the crumb of this embodiment.

The shape of the hole in the die is circular, preferably with a diameter of 1 mm to 4 mm, more preferably 1.5 mm to 3 mm.

If the diameter is small, the volume of the crumb will be small and the blocking property will deteriorate; if the diameter is large, the volume of the crumb will tend to be large and the transport efficiency, asphalt solubility and oil absorption will tend to be poor. From the viewpoint of solubility, it is preferable to make the crumb volume 4 mm or less, but since other factors are also involved in controlling the crumb volume, making the crumb volume 4 mm or less corresponds to making the crumb volume 110 mm ³ or less. It's not a translation.

The total area of the pores, that is, the total opening area is preferably 1,500 to 8,000 mm ² , more preferably 3,000 to 5,000 mm ² . If it is smaller than 1500 mm ² , the crumb will be long, the aspect ratio will be large, and the blocking property will tend to deteriorate. When it is larger than 8000 mm ² , the crumb tends to be short and the volume tends to be small, so that the blocking property tends to deteriorate. However, since factors other than the opening area are also involved in crumb length control, the lower limit value of volume and the upper limit value of area do not necessarily correspond.

The cutter blade has a shape in which the blade extends radially from the center, and is preferably installed adjacent to the outlet of the extrusion dryer. The number of blades and the number of rotations of the blades are preferably in the range of number of cutter blades x number of rotations = 4,500 to 36,000 rpm. When the speed is lower than 4,500 rpm, the crumbs tend to be long and the blocking property deteriorates, and when it is higher than 36,000 rpm, the crumbs tend to be short and the volume tends to be small, so the blocking property tends to deteriorate. However, since factors other than the number of revolutions also affect volume control, 36,000 rpm and the lower limit of volume do not necessarily correspond.

Moreover, it is preferable that the specific energy of the extrusion dryer is 0.12 kWh/kg or less. More preferably it is 0.10 kWh/kg or less, and still more preferably 0.09 kWh/kg or less. When the specific energy is larger than 0.12 kWh/kg, the foaming ratio is high and the specific gravity tends to be low, so that transport efficiency and blocking properties tend to deteriorate. However, since factors other than specific energy also influence the control of specific gravity, 0.12 kWh/kg and the lower limit of specific gravity do not necessarily correspond.

<Step 3>
The crumb obtained in <Step 2> is dried on a drying conveyor (equipment that blows hot air from the bottom while being vibrated and conveyed by the conveyor) to obtain crumb with a moisture content of 1% by mass or less.

The moisture content of the crumb after passing through <Step 3> is 1% by mass or less, preferably 0.95% by mass or less, and more preferably 0.9% by mass or less.

As described above, the aqueous slurry is dehydrated in <Step 1>, and the crumb component that has a moisture content of more than 60% by mass and 80% by mass or less and does not pass through a sieve with a mesh size of 1.5 mm is 80% by mass of the total crumb. Obtain the above crumb, and perform dehydration and drying in <Step 2> to obtain crumbs with a moisture content of 3 to 30% by mass, and dry in <Step 3> on a drying conveyor to obtain crumbs. The water content can be adjusted to 1% by mass or less.

(Asphalt composition)
The asphalt composition of this embodiment includes the block copolymer crumb of this embodiment and asphalt. Furthermore, in the asphalt composition of the present embodiment, the blending ratio of the block copolymer crumb is preferably 0.5 parts by mass or more and 50 parts by mass or less, more preferably 1 part by mass, based on 100 parts by mass of asphalt. Parts by weight or more and 30 parts by weight or less, more preferably 2 parts by weight or more and 20 parts by weight or less. When the blending ratio of the above polymer is 0.5 parts by mass or more, a good softening point tends to be obtained, and when it is 50 parts by mass or less, a good balance between physical properties and viscosity (processability) tends to be obtained. It is in.

<Asphalt>
As the asphalt that can be used in this embodiment, for example, asphalt obtained as a byproduct during oil refining (petroleum asphalt), a natural product (natural asphalt), or a mixture of these and petroleum, etc. Can be mentioned. Its main component is bitumen. Specific examples include straight asphalt, semi-blown asphalt, blown asphalt, cutback asphalt containing tar, pitch, and oil, and asphalt emulsion. These may be used in combination.

As a suitable asphalt, the penetration (measured according to JIS-K2207) is preferably 30 (1/10 mm) or more and 300 (1/10 mm) or less, more preferably 40 (1/10 mm) or more and 200 (1/10 mm). ) or less, more preferably 45 (1/10 mm) or more and 150 (1/10 mm) or less.

In this embodiment, any petroleum resin can be further blended as needed. The type of petroleum resin is not particularly limited, but includes, for example, aliphatic petroleum resins such as C5 petroleum resins, aromatic petroleum resins such as C9 petroleum resins, and alicyclic petroleum resins such as dicyclopentadiene petroleum resins. Petroleum resins such as petroleum resins and C5/C9 copolymer petroleum resins, and hydrogenated petroleum resins obtained by hydrogenating these petroleum resins can be used. The amount of petroleum resin is not particularly limited, but it is preferably 1 part by mass or more and 10 parts by mass or less, more preferably 2 parts by mass or more and 6 parts by mass or less, based on 100 parts by mass of asphalt.

In this embodiment, arbitrary additives can be further blended as needed. The type of additive is not particularly limited as long as it is commonly used in blending thermoplastic resins and rubbery polymers. Examples of additives include, but are not limited to, calcium carbonate, magnesium carbonate, magnesium hydroxide, calcium sulfate, barium sulfate, silica, clay, talc, mica, wollastonite, montmorillonite, zeolite, alumina, titanium oxide, Inorganic fillers such as magnesium oxide, zinc oxide, slag wool, glass fiber, pigments such as carbon black and iron oxide, stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, ethylene bisstearamide, etc. Lubricants, mold release agents, paraffinic process oils, naphthenic process oils, aromatic process oils, paraffins, organic polysiloxanes, softeners and plasticizers such as mineral oil, hindered phenolic antioxidants, phosphorus thermal stabilizers antioxidants, hindered amine light stabilizers, benzotriazole ultraviolet absorbers, flame retardants, antistatic agents, reinforcing agents such as organic fibers, glass fibers, carbon fibers, metal whiskers, colorants, other additives, Examples of such mixtures include those described in "Rubber/Plastic Compounded Chemicals" (edited by Rubber Digest, Japan). The amount of the additive is not particularly limited and can be selected as appropriate, but it is usually 50 parts by mass or less per 100 parts by mass of asphalt.

In addition to the block copolymer crumb of this embodiment, other polymers can be further blended into the asphalt composition of this embodiment. Other polymers include, but are not particularly limited to, olefin elastomers such as natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, and ethylene-propylene copolymers; chloroprene rubber, acrylic rubber, and ethylene-vinyl acetate copolymers. , olefin polymers such as ethylene-ethyl acrylate copolymer, atactic polypropylene, and amorphous polyalphaolefin; blends of polypropylene and ethylene-propylene copolymer; blends of polypropylene and ethylene-propylene-diene terpolymer , olefin thermoplastic elastomers which are copolymers of ethylene and the like. These may be used alone or in combination.

From the viewpoint of increasing heat aging resistance and softening point, it is preferable to use the olefin polymer and other polymers together. Among these, it is more preferable to use an olefin polymer having at least a propylene unit. The amount of other polymers added is preferably 5 to 40 parts by mass based on 100 parts by mass of the block copolymer crumb of this embodiment.

Increasing the solubility of the block copolymer crumb and other polymers of the present embodiment in asphalt, improving the adhesion resistance of the asphalt composition to aggregate, and increasing the flow rutting resistance of the asphalt mixture, When it is necessary to increase wear resistance, crosslinking is preferred. Examples of the crosslinking agent include, but are not limited to, sulfur-sulfur compound type, phosphorus type, organic peroxide type, epoxy type, isocyanate type, resin type, amine type, metal chelate type, thiuram, and the like. From these, one type may be used, or two or more types may be used. Moreover, two or more types from the same system may be used. Among these, sulfur, sulfur-based compounds, and polyphosphoric acid are preferable because they have the above-mentioned effects and are economical.

The asphalt composition of the present embodiment can be used in the fields of road paving, roofing/waterproof sheets, and sealants, and can be particularly preferably used in the field of road paving. Among these, road paving is suitable. The block copolymer crumb of this embodiment has excellent asphalt solubility, that is, it dissolves in asphalt in a short time, so productivity is improved.

Hereinafter, the present embodiment will be specifically described with reference to examples, but the present embodiment is not limited to these embodiments in any way.

The measurement methods for polymers and asphalt compositions in Examples and Comparative Examples are as follows.

<Content of vinyl aromatic monomer units in polymer (styrene content)>
By preparing a chloroform solution of a measurement sample (a block copolymer prepared according to the following production example) and using a spectrophotometer (manufactured by JASCO: V-550) to detect the absorption of UV 254 nm by the phenyl group of styrene. , the amount of bound styrene (% by mass) was measured. The amount of bound styrene was a value rounded to the first decimal place.

<Amount of vinyl bonds in the polymer and hydrogenation rate of double bonds in the conjugated diene monomer unit>
The amount of vinyl bonds in the polymer and the hydrogenation rate of double bonds in the conjugated diene monomer units were measured by nuclear magnetic resonance spectroscopy (NMR) under the following conditions.

Both the amount of vinyl bonds and the hydrogenation rate were measured using a polymer sample after the hydrogenation reaction. Furthermore, the reaction solution after the hydrogenation reaction was precipitated in a large amount of methanol to precipitate and recover the hydrogenated polymer.

Next, the hydrogenated polymer was extracted with acetone, and the extract was vacuum dried and used as a sample for 1H-NMR measurement.

The conditions for 1H-NMR measurement were as follows.
(Measurement condition)
Measuring equipment: JNM-LA400 (manufactured by JEOL)
Solvent: Deuterated chloroform Measurement sample: Samples taken before and after hydrogenating the polymer Sample concentration: 50 mg/mL
Observation frequency: 400MHz
Chemical shift standard: TMS (tetramethylsilane)
Pulse delay: 2.904 seconds Number of scans: 64 times Pulse width: 45°
Measurement temperature: 26℃
The vinyl bond amount and hydrogenation rate were expressed in units of mol%, and values were rounded to the first decimal place.

<Weight average molecular weight>
The measurement was performed by gel permeation chromatography (GPC) using a measuring device manufactured by Tosoh. Tetrahydrofuran was used as the solvent, and the measurement temperature was 40°C. In addition, the weight average molecular weight (polystyrene equivalent molecular weight) was determined from the molecular weight of the peak in the chromatogram using a calibration curve (created using the peak molecular weight of standard polystyrene) obtained from measurements of commercially available standard polystyrene.

(Measurement condition)
GPC: HLC-8320GPC (manufactured by Tosoh Corporation)
Detector: RI
Column: PLgel Column MiniMix-C 4.6mmΦ×300mm (manufactured by Agilent Technologies)
Solvent: THF
Flow rate: 0.6mL/min
Concentration: 0.5mg/mL
Column temperature: 40℃
Injection volume: 20μL
The weight average molecular weight was rounded to the nearest 1000.

<Melt flow rate (MFR)>
The MFR was measured in accordance with method A of JIS-K7210 under conditions equivalent to the ASTM G conditions of a test temperature of 200° C. and a test load of 5 kgf. The value was rounded to the second decimal place.

<Measurement of crumb shape>
First, when the shape of the crumb was likened to a cylinder, it was determined whether it was tower-shaped or tank-shaped, and the volume was determined according to the rules shown below. Here, the tower type refers to a shape in which the height is longer than the diameter of the bottom when viewed as a cylinder, and the tank type refers to a shape in which the diameter of the bottom is longer than the height. Thirty crumbs were randomly extracted and the length and width were measured using calipers. In both tower and tank types, the longest side length was taken as the length, and the shortest side length was taken as the width. Similarly, 30 crumbs were randomly extracted and their weight was measured using an electronic balance. The length and width were expressed in mm, and values were rounded to the second decimal place. The weight was expressed in grams, and the value was rounded to the fifth decimal place.

After measuring the length, width, and weight, an outlier test was performed on the measurement results. Outlier tests were performed using the Smirnov-Grubbs test. Calculate the average value and variance of the 30 measurement data, calculate the test statistics t and the p value at t, and exclude those with a p value of 0.05 or less (5%) as abnormal values, Calculated as an average value.

<How to calculate crumb aspect ratio>
The aspect ratio of the crumb was calculated from the length and width of the shape measurement described above according to the following formula.
Aspect ratio=length/width Note that the length and width used here are the average value of length and average value of width calculated by the method described above. The aspect ratio was a value rounded to the third decimal place.

<How to calculate the volume of crumb>
The crumb volume was calculated from the length and width of the crumb according to the following formula.
For tower type: Crumb volume = pi x (width/2) ² x length For tank type: crumb volume = pi x (length/2) ² x width The length and width are the average length and average width calculated by the method described above. The volume was expressed in units of mm ³ and rounded to the second decimal place.

<How to calculate the specific gravity of crumbs>
The specific gravity of the crumb was calculated from the weight and volume of the shape measurement described above according to the following formula.
Specific gravity=weight/volume Note that the weight used here is the average value of the weights calculated by the method described above. The specific gravity was expressed in g/mm ³ units, and the value was rounded to the sixth decimal place.

<Evaluation of crumb particle size>
Using a sieve shaker (Octagon Digital, manufactured by Seishin Enterprise Co., Ltd.), 300 g of crumbs were placed over a sieve with an opening of 3.35 mm and shaken for 15 minutes, and the amount of crumbs remaining on each sieve and the amount of crumbs that passed through the sieve were measured. was measured, and the proportion (mass %) of crumbs passing through a sieve with an opening of 3.35 mm was calculated. The particle size was expressed in mass %, and the value was rounded to the first decimal place.

<Evaluation of transportation efficiency>
The obtained block copolymer crumb was packed into a flexible container having a width of 110 cm, a depth of 110 cm, and a height of 215 cm until the height reached 190 cm. The total weight of the block copolymer crumb at that time was measured. The evaluation criteria were as follows, and A to C were considered acceptable, with A and B being particularly excellent in transport efficiency. When packing, the top was smoothed, but no pushing was done.
A: 700kg or more B: 600kg to 700kg
C: 550kg to 600kg
D: Less than 550kg

<Evaluation of blocking property>
After storing the container filled with the block copolymer crumb prepared for transport efficiency evaluation at approximately 30°C for three months, it was lifted out, a circular hole with a diameter of 45 cm placed in the center of the bottom of the container was opened, and the discharge was observed. was observed and evaluated. The evaluation criteria were as follows, and A to C were considered acceptable, with A and B being particularly excellent in blocking properties.
A: As soon as it was released, it began to drain naturally without clogging, and the entire amount was able to be drained.
B: A slight blockage occurred during discharge, and the entire amount could be discharged by gently shaking the container at any point.
C: Severe clogging occurred during discharge, and the entire amount was able to be discharged by vigorously shaking an arbitrary part of the container.
D: It was impossible to discharge.

<Creation of asphalt composition>
350g of asphalt (Straight Asphalt 80-100 (manufactured by Petronas)) was put into a 750mL metal can, and the metal can was sufficiently immersed in an oil bath at 180°C.Next, each block copolymer was added to the molten asphalt. It was added little by little while stirring so that the combined amount was 4% by mass.

After each material was completely added, the mixture was stirred at a rotational speed of 3000 rpm for 60 minutes to prepare an asphalt composition.

<Evaluation of asphalt solubility>
In the process of dissolving into asphalt, the solubility was evaluated based on the following evaluation criteria based on the dissolution time. The evaluation criteria were as follows, and A to C were considered to be acceptable, with A and B being particularly excellent in asphalt solubility.
A: Dissolution time is less than 15 minutes B: Dissolution time is 15 minutes or more and less than 30 minutes C: Dissolution time is 30 minutes or more and less than 60 minutes D: Dissolution time is 60 minutes or more

<Evaluation of oil absorption>
10 g of the obtained block copolymer crumb was placed in a bag made of 200 mesh wire mesh. 2 L of PW90 was placed in a 3 L poly beaker, and the temperature of the poly beaker was adjusted to 35°C in a hot water bath. When PW90 stabilized at 35° C., the whole wire mesh bag containing crumbs prepared above was immersed in PW90 for 1 minute. Thereafter, the bag was quickly taken out and left on a cloth for 1.5 hours.

After standing still, a molded plate (3 mm thick, 30 cm square, 2 sheets) and 10 cmφ filter paper (2 sheets stacked on top and bottom) were prepared, and a load of 2.0 kgf was applied for 3 minutes. The bag was then released and the oil-absorbed crumbs were collected. The weight of the crumb before and after oil absorption was measured, and the oil absorption amount was calculated according to the following formula.
Oil absorption amount (phr) = (crumb weight after oil absorption - crumb weight before oil absorption) / crumb weight before oil absorption

The evaluation criteria were as follows, and A to C were considered to be acceptable, with A and B being particularly excellent in oil absorption.
A: Oil absorption is 300 phr or more B: Oil absorption is 225 phr or more and less than 300 phr C: Oil absorption is 150 phr or more and less than 225 phr D: Oil absorption is less than 150 phr

<Production of block copolymer>
<Preparation of hydrogenation catalyst>
Charge 100 liters of dried and purified cyclohexane into a reaction vessel purged with nitrogen, add 10 moles of bis(η5-cyclopentadienyl)titanium dichloride, and add an n-hexane solution containing 20 moles of trimethylaluminum while stirring thoroughly. The mixture was reacted at room temperature for about 3 days.

<Manufacture example 1>
Polymerization was carried out in the following manner using a stirring device and a jacketed tank reactor with an internal volume of 7 m ³ .

First step:
After charging 3 tons of cyclohexane into the reactor and adjusting the temperature to 40°C, 0.05 mol of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as TMEDA) was added per 1 mol of n-butyllithium. Then, 10 parts by mass of styrene as a monomer was added over about 3 minutes.

Second step:
After adjusting the solution temperature in the container to 40° C., 0.054 parts by mass of n-butyllithium was added to 100 parts by mass of all monomers, and polymerization was carried out for 30 minutes.

Third step:
Next, 58 parts by mass of butadiene and 22 parts by mass of styrene were each continuously supplied to the reactor at a constant rate over 6 minutes. Thereafter, it was allowed to react for 60 minutes. During this time, the reactor internal temperature was adjusted to about 80°C.

Fourth step:
Thereafter, 10 parts by mass of styrene as a monomer was added over about 3 minutes, and the reaction was carried out for 30 minutes while adjusting the reactor internal temperature to about 80°C. Then, 0.0 parts of methanol was added to 1 mole of n-butyllithium. 9 mol was added.
In addition, the total monomers were supplied in an amount of 15 parts by mass based on 100 parts by mass of cyclohexane.

Fifth step:
Next, 100 ppm of titanium was added to the hydrogenation catalyst based on the mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C. When the hydrogenation rate reached 95%, the hydrogen supply was stopped, and then octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added to the mass of the polymer as a stabilizer. 0.25% by mass of the block copolymer was added to obtain a cyclohexane solution of the block copolymer.

The resulting cyclohexane solution of the block copolymer was steam stripped at 95° C. for 1 hour. Steam stripping was carried out by adding styrene-maleic acid copolymer Na salt as a crumbling agent.

The concentration of the block copolymer crumb precursor in the obtained aqueous slurry was 5% by mass.
Next, the obtained aqueous slurry containing the block copolymer crumb precursor was sent to a vibrating screen with apertures of 1.5 mm to perform dehydration treatment (<Step 1>).

This block copolymer crumb precursor was subjected to dehydration and drying treatment (<Step 2>) using a two-stage single screw extrusion dryer in which a dehydration treatment means and a drying treatment means were integrated. . At the outlet of the extrusion dryer, 42 dies each having a hole diameter of 3 mm and 15 holes were installed. The total area of the openings was 4453 ^mm2 . Further, a cutter having 10 cutter blades arranged radially was used, and the rotation speed was set to 2200 rpm.

The block copolymer was fed at a feed rate of 3.4 t/h, and was continuously fed to an extrusion dryer, and crumbs were continuously discharged from the outlet of the drying extruder. Note that the rotation speed of the screw was adjusted so that the specific energy was 0.12 kWh/kg.

Thereafter, the block copolymer crumb obtained above was dried with hot air at about 90° C. using a drying conveyor (<Step 3>), and block copolymer crumb 1 was collected. Table 1 shows the polymerization conditions and analysis results for block copolymer crumb 1, and Table 2 shows the conditions for step 2.

<Production Examples 2 to 11, 19 to 23>
Block copolymer crumbs 2 to 11 and 19 to 23 were obtained in the same manner as in Production Example 1 except that the conditions of Step 2 were changed as shown in Table 2. Table 1 shows the polymerization conditions and analysis results of the block copolymer crumb.

<Manufacture example 12>
Block copolymer crumb 12 was obtained in the same manner as Production Example 1 except that the hydrogen supply was stopped when the hydrogenation rate reached 70% and the conditions of Step 2 were changed as shown in Table 2. Ta. Table 1 shows the polymerization conditions and analysis results for block copolymer crumb 12.

<Manufacture example 13>
Polymerization was carried out in the following manner using a stirring device and a jacketed tank reactor with an internal volume of 7 m ³ .

First step:
After charging 3 tons of cyclohexane into the reactor and adjusting the temperature to 40° C., 30 parts by mass of styrene as a monomer was added over about 3 minutes.

Second step:
After adjusting the solution temperature in the container to 40° C., 0.144 parts by mass of n-butyllithium was added to 100 parts by mass of all monomers, and polymerization was carried out for 30 minutes.

Third step:
Next, 70 parts by mass of butadiene was continuously supplied to the reactor at a constant rate over 6 minutes. Thereafter, it was allowed to react for 60 minutes. During this time, the reactor internal temperature was adjusted to about 80°C.
In addition, the total monomers were supplied in an amount of 15 parts by mass based on 100 parts by mass of cyclohexane.

Fourth step:
Thereafter, 0.35 mol of dimethyldichlorosilane was added as a coupling agent per 1 mol of n-butyllithium, and the reaction was carried out for 10 minutes while adjusting the reactor internal temperature to about 80°C.

Fifth step:
Next, 0.25% by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added to the mass of the polymer as a stabilizer, and a cyclohexane solution of the block copolymer was added. I got it.

The resulting cyclohexane solution of the block copolymer was steam stripped at 95° C. for 1 hour. During steam stripping, styrene-maleic acid copolymer Na salt was added as a crumbling agent.

The concentration of the block copolymer crumb precursor in the obtained aqueous slurry was 5% by mass.
Next, the obtained aqueous slurry containing the block copolymer crumb precursor was sent to a vibrating screen with apertures of 1.5 mm to perform dehydration treatment (<Step 1>).

Thereafter, block copolymer crumb 13 was obtained in the same manner as in Production Example 1 except that the conditions were changed as shown in Table 2. Table 1 shows the polymerization conditions and analysis results of block copolymer crumb 13.

<Manufacture example 14>
Block copolymer crumb 14 was obtained in the same manner as in Production Example 13, except that the monomers and additive types and amounts were changed as shown in Table 1, and the conditions of Step 2 were changed as shown in Table 2. Table 1 shows the polymerization conditions and analysis results of block copolymer crumb 14.

<Manufacture example 15>
Polymerization was carried out in the following manner using a stirring device and a jacketed tank reactor with an internal volume of 7 m ³ .

First step:
After charging 3 tons of cyclohexane into the reactor and adjusting the temperature to 40°C, 0.05 mol of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as TMEDA) was added per 1 mol of n-butyllithium. Then, 20 parts by mass of styrene as a monomer was added over about 3 minutes.

Second step:
After adjusting the solution temperature in the container to 40° C., 0.103 parts by mass of n-butyllithium was added to 100 parts by mass of all monomers, and polymerization was carried out for 30 minutes.

Third step:
Next, 58 parts by mass of butadiene and 22 parts by mass of styrene were each continuously supplied to the reactor at a constant rate over 6 minutes. Thereafter, it was allowed to react for 60 minutes. During this time, the reactor internal temperature was adjusted to about 80°C. In addition, the total monomers were supplied in an amount of 15 parts by mass based on 100 parts by mass of cyclohexane.

Fourth step:
Thereafter, 0.18 mol of tetramethoxysilane was added as a coupling agent per 1 mol of n-butyllithium, and the reactor was reacted for 10 minutes while adjusting the internal temperature to about 80°C. 0.3 mol was added per 1 mol of lithium.

Fifth step:
Next, 100 ppm of titanium was added to the hydrogenation catalyst based on the mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C. When the hydrogenation rate reached 70%, the hydrogen supply was stopped, and then octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added to the mass of the polymer as a stabilizer. 0.25% by mass of the block copolymer was added to obtain a cyclohexane solution of the block copolymer.

The resulting cyclohexane solution of the block copolymer was steam stripped at 95° C. for 1 hour. During steam stripping, styrene-maleic acid copolymer Na salt was added as a crumbling agent.

The concentration of the block copolymer crumb precursor in the obtained aqueous slurry was 5% by mass.
Next, the obtained aqueous slurry containing the block copolymer crumb precursor was sent to a vibrating screen with apertures of 1.5 mm to perform dehydration treatment (<Step 1>).

Thereafter, block copolymer crumb 15 was obtained in the same manner as in Production Example 1 except that the conditions were changed as shown in Table 2. Table 1 shows the polymerization conditions and analysis results of block copolymer crumb 15.

<Manufacture example 16>
Block copolymer crumb 16 was obtained in the same manner as Production Example 1 except that the polymerization conditions were changed as shown in Table 1 and the conditions of Step 2 were changed as shown in Table 2. Table 1 shows the polymerization conditions and analysis results of block copolymer crumb 16.

<Manufacture example 17>
Polymerization was carried out in the following manner using a stirring device and a jacketed tank reactor with an internal volume of 7 m ³ .

First step:
After charging 3 tons of cyclohexane into the reactor and adjusting the temperature to 40° C., 15 parts by mass of styrene as a monomer was added over about 5 minutes.

Second step:
After adjusting the solution temperature in the container to 40° C., 0.059 parts by mass of n-butyllithium was added to 100 parts by mass of all monomers, and polymerization was carried out for 30 minutes.

Third step:
Next, 70 parts by mass of butadiene was continuously supplied to the reactor at a constant rate over 6 minutes. Thereafter, it was allowed to react for 60 minutes. During this time, the reactor internal temperature was adjusted to about 80°C.
In addition, the total monomers were supplied in an amount of 15 parts by mass based on 100 parts by mass of cyclohexane.

Fourth step:
Thereafter, 15 parts by mass of styrene as a monomer was added over about 4 minutes, and the reactor was reacted for 30 minutes while adjusting the internal temperature to about 80°C. 9 mol was added.
In addition, the total monomers were supplied in an amount of 15 parts by mass based on 100 parts by mass of cyclohexane.

Fifth step:
Next, 0.25% by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added to the mass of the polymer as a stabilizer, and a cyclohexane solution of the block copolymer was added. I got it.

The resulting cyclohexane solution of the block copolymer was steam stripped at 95° C. for 1 hour. During steam stripping, styrene-maleic acid copolymer Na salt was added as a crumbling agent.

The concentration of the block copolymer crumb precursor in the obtained aqueous slurry was 5% by mass.
Next, the obtained aqueous slurry containing the block copolymer crumb precursor was sent to a vibrating screen with apertures of 1.5 mm to perform dehydration treatment (<Step 1>).

Thereafter, block copolymer crumb 17 was obtained in the same manner as in Production Example 1 except that the conditions were changed as shown in Table 2. Table 1 shows the polymerization conditions and analysis results of block copolymer crumb 17.

<Manufacture example 18>
Block copolymer crumb 18 was obtained in the same manner as Production Example 17 except that the conditions of Step 2 were changed as shown in Table 2. Table 1 shows the polymerization conditions and analysis results of block copolymer crumb 18.

<Manufacture example 24>
Polymerization was carried out in the following manner using a stirring device and a jacketed tank reactor with an internal volume of 7 m ³ .

First step:
After charging 3 tons of cyclohexane into the reactor and adjusting the temperature to 40° C., 30 parts by mass of styrene as a monomer was added over about 3 minutes.

Second step:
After adjusting the solution temperature in the container to 40° C., 0.15 parts by mass of n-butyllithium was added to 100 parts by mass of all monomers, and polymerization was carried out for 30 minutes.

Third step:
Next, 70 parts by mass of butadiene was continuously supplied to the reactor at a constant rate over 6 minutes. Thereafter, it was allowed to react for 60 minutes. During this time, the reactor internal temperature was adjusted to about 80°C.
In addition, the total monomers were supplied in an amount of 15 parts by mass based on 100 parts by mass of cyclohexane.

Fourth step:
Thereafter, 0.25 mol of dimethyldichlorosilane was added as a coupling agent per 1 mol of n-butyllithium, and the reaction was carried out for 10 minutes while adjusting the internal temperature of the reactor to about 80°C.

Fifth step:
Next, 0.25% by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added to the mass of the polymer as a stabilizer, and a cyclohexane solution of the block copolymer was added. I got it.

The resulting cyclohexane solution of the block copolymer was steam stripped at 95° C. for 1 hour. During steam stripping, styrene-maleic acid copolymer Na salt was added as a crumbling agent.

The concentration of the block copolymer crumb precursor in the obtained aqueous slurry was 5% by mass.
Next, the obtained aqueous slurry containing the block copolymer crumb precursor was sent to a vibrating screen with apertures of 1.5 mm to perform dehydration treatment (<Step 1>).

Thereafter, a block copolymer crumb 24 was obtained in the same manner as in Production Example 1 except that the conditions were changed as shown in Table 2. Table 1 shows the polymerization conditions and analysis results for block copolymer crumb 24.

<Production Examples 25 and 26>
Block copolymer crumbs 25 and 26 were obtained in the same manner as in Production Example 1, except that the polymerization conditions were changed as shown in Table 1 and the conditions of Step 2 were changed as shown in Table 2. Table 1 shows the block copolymer crumb polymerization conditions and analysis results.

<Production example 27>
Polymerization was carried out in the following manner using a stirring device and a jacketed tank reactor with an internal volume of 7 m ³ .

First step:
After charging 3 tons of cyclohexane into the reactor and adjusting the temperature to 40°C, 0.3 mol of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as TMEDA) was added per 1 mol of n-butyllithium. Then, 24 parts by mass of styrene as a monomer was added over about 3 minutes.

Second step:
After adjusting the solution temperature in the container to 40° C., 0.15 parts by mass of n-butyllithium was added to 100 parts by mass of all monomers, and polymerization was carried out for 30 minutes.

Third step:
Next, 76 parts by mass of butadiene was continuously fed into the reactor at a constant rate over 6 minutes. Thereafter, it was allowed to react for 60 minutes. During this time, the reactor internal temperature was adjusted to about 80°C. In addition, the total monomers were supplied in an amount of 15 parts by mass based on 100 parts by mass of cyclohexane.

Fourth step:
Thereafter, 0.11 mol of tetramethoxysilane was added as a coupling agent per 1 mol of n-butyl lithium, and the reactor was reacted for 10 minutes while adjusting the internal temperature to about 80°C. 0.7 mol was added per 1 mol of lithium.

Next, 100 ppm of titanium was added to the hydrogenation catalyst based on the mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 80°C. When the hydrogenation rate reached 50%, the hydrogen supply was stopped, and then octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added to the mass of the polymer as a stabilizer. 0.25% by mass of the block copolymer was added to obtain a cyclohexane solution of the block copolymer.

The resulting cyclohexane solution of the block copolymer was steam stripped at 95° C. for 1 hour. Steam stripping was carried out by adding styrene-maleic acid copolymer Na salt as a crumbling agent.
The concentration of the block copolymer crumb precursor in the obtained aqueous slurry was 5% by mass.
Next, the obtained aqueous slurry containing the block copolymer crumb precursor was sent to a vibrating screen with apertures of 1.5 mm to perform dehydration treatment (<Step 1>).

Thereafter, block copolymer crumb 27 was obtained in the same manner as in Production Example 1 except that the conditions were changed as shown in Table 2. Table 1 shows the polymerization conditions and analysis results of block copolymer crumb 27.

<Examples 1 to 18>
Table 3 shows the evaluation results for block copolymer crumbs 1 to 18.

<Comparative Examples 1 to 5>
Table 3 shows the evaluation results for block copolymer crumbs 19 to 23.

<Comparative Examples 6 to 9>
Table 3 shows the evaluation results for block copolymer crumbs 24 to 27.

Claims (9)

A polymer block A mainly composed of vinyl aromatic monomer units,
A polymer block B mainly consisting of conjugated diene monomer units and/or a polymer block C consisting of vinyl aromatic monomer units and conjugated diene monomer units,
A crumb of a block copolymer or its hydrogenated product having
A crumb that satisfies (1) to (6) below.
(1) The average weight per crumb is 0.0080 to 0.0500 g,
(2) The average value of the aspect ratio per crumb is 1.00 to 3.50,
(3) The average volume per crumb is 18.0 to 110 mm ³ ,
(4) The average value of specific gravity per crumb is 2.0×10 ⁻⁴ to 1.0×10 ⁻³ g/mm ³ ,
(5) The components that pass through a sieve with an opening of 3.35 mm are 41% by mass or more of the total crumb,
(6) The crumb melt flow rate is 0.3 g/10 minutes or less under G conditions. The crumb according to claim 1, wherein the average weight per crumb is 0.0100 to 0.0300 g. The crumb according to claim 1, wherein the average weight per crumb is 0.0120 to 0.0200 g. The crumb according to claim 1, wherein the average volume per crumb is 20.0 to 90.0 mm ³ . The crumb according to claim 1, wherein the average volume per crumb is 20.0 to 80.0 mm ³ . The crumb according to claim 1, wherein the average value of specific gravity per crumb is 2.0×10 ⁻⁴ to 5.0×10 ⁻⁴ g/mm ³ . The crumb according to claim 1, wherein the average value of the aspect ratio per crumb is 1.00 to 1.60. The content of vinyl aromatic monomer units in the block copolymer or hydrogenated product thereof is 20 to 50% by mass,
The vinyl bond amount of the conjugated diene monomer unit is 5 to 50 mol%,
The crumb according to claim 1, having a weight average molecular weight of 100,000 to 500,000. 0.5 to 50 parts by mass of crumb according to any one of claims 1 to 8;
100 parts by mass of asphalt,
An asphalt composition containing.