JPH08301956A - Bitumen modifier and bitumen composition - Google Patents

Abstract

PURPOSE: To obtain a bitumen modifier which is excellent in solubility in bitumen, softening point, rate of penetration, toughness, and tenacity and gives a bitumen compsn. greatly improved in flow resistance and to obtain a bitumen compsn. contg. the modifier. CONSTITUTION: This bitumen modifier is a block copolymer having at least one polymer block mainly comprising vinylarom. hydrocarbon units and at least one polymer block mainly comprising conjugated diene units and has such characteristics that the wt. average mol.wt. is 200,000-1,000,000; that the vinylarom. hydrocarbon content is 5-60wt.%; that at least one polymer block mainly comprising vinylarom. hydrocarbon units is at the molecular end and the amt. of the conjugated diene units has such a tapered distribution that the amt. gradually decreases from the molecular end; and that the block copolymer has a linear structure.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a bitumen modifier and a bituminous composition, and more specifically, it has excellent solubility of the modifier with respect to bitumen, and also has excellent penetration, softening point, toughness, tenacity and the like. TECHNICAL FIELD The present invention relates to a bituminous modifier and a bituminous composition which are excellent in a binder property and a mixture property such as fluidity resistance and are particularly suitable for a plant mix method at the time of manufacturing a bituminous composition for road paving.

[0002]

2. Description of the Related Art As a road paving material, a bituminous composition is generally used in which bitumen such as asphalt is mixed with aggregate such as crushed stone, filler, and various modifiers. In recent years, construction of drainage pavement to add drainage and noise reduction functions to highways, or shortening of the life of paved roads due to rutting etc. due to weight increase of traffic vehicles and increase in traffic volume, etc. On the other hand, fluid resistance and durable pavement is being constructed. In these, it is desired that the bituminous composition used as a paving material has improved fluidity without deteriorating various functions.

Conventionally, styrene-butadiene- has been used as a bitumen modifier in order to improve the flow resistance of a bituminous composition.
Although it has been proposed to add a styrene type block copolymer (hereinafter, abbreviated as “SB block copolymer”), the performance requirements such as fluidity resistance have not been sufficiently satisfied. For example, Japanese Patent Publication No. 57-17022 discloses that
As a bitumen modifier, an asphalt composition in which chloroprene rubber and an SB block copolymer having a small molecular weight are blended has been proposed. However, the effect of improving the fluidity resistance at high temperature of this asphalt composition is not yet sufficient. Further, Japanese Patent Laid-Open No. 6-41439 discloses a molecular weight of 1
An asphalt composition containing a linear SB block copolymer composed of a high molecular weight component of 0 to 200,000 and a low molecular weight component of 100,000 or less in molecular weight is disclosed. This asphalt composition is suitable for drainage pavement, has a high softening point,
Although it has characteristics such as high toughness and tenacity, the effect of improving fluidity is not sufficient.

On the other hand, the preparation of a bituminous composition for road paving is
By methods such as the premix method and the plant mix method,
It is carried out by mixing the respective components. However, since the conventional SB block copolymer used as a modifier has poor solubility in bitumen, there is a problem that the modifying effect cannot be sufficiently exhibited by these mixing methods. Was there. In particular, in the plant mix method in which the modifier is mixed with bitumen, aggregate, etc. in a short time, the dissolution of the modifier becomes insufficient, so that the flow resistance of the obtained bituminous composition is hardly improved. have.

Conventionally, in order to improve the solubility of the block copolymer in bitumen, for example, 10 to 40% by weight of a low molecular weight block copolymer having a molecular weight of 65 to 150,000 and mineral oil 6 are used.
0 to 90 parts by weight of an asphalt modifier (Japanese Patent Publication No. 58-13098) or an asphalt modifier composed of rubber, a liquid dispersant, an oily hydrocarbon and a foaming agent (Japanese Patent Laid-Open No. 50-6629). Gazette) is proposed. However, in these methods, in order to improve the solubility of the block copolymer, it is necessary to add a large amount of an oily or liquid additive, so that various physical properties such as flow resistance are not sufficient. I have a problem.

[0006]

The object of the present invention is to provide a bitumen composition having excellent solubility in bitumen, excellent softening point, penetration, toughness, tenacity, etc., and significantly improved flow resistance. An object of the present invention is to provide a bituminous modifier capable of giving a product and a bitumen composition containing the bitumen modifier.

The inventors of the present invention have conducted extensive studies in order to overcome the above-mentioned problems of the prior art, and as a result, a block copolymer obtained by polymerizing a vinyl aromatic compound and a conjugated diene, At least one end of the polymer chain is a polymer block mainly composed of vinyl aromatic hydrocarbon, and contains a polymer block having a tapered distribution structure in which the conjugated diene content gradually decreases from the copolymer chain end, A high molecular weight, linear block copolymer has excellent solubility in bitumen, and also has a softening point, penetration, toughness,
It was found that the binder properties such as tenacity are excellent. Further, it was found that even when the block copolymer is mixed with bitumen, aggregate and the like by the plant mix method, a bituminous composition having sufficiently high dynamic stability (flow resistance) can be obtained. . The present invention has been completed based on these findings.

[0008]

Thus, according to the present invention, at least one polymer block (A) mainly composed of vinyl aromatic hydrocarbons and a polymer block (B) mainly composed of conjugated dienes. A bituminous modifier comprising a block copolymer containing at least one of (a) a block copolymer having a weight average molecular weight of 200,000 to 1,
Polymer block (A) having a vinyl aromatic hydrocarbon content of 5 to 60% by weight and (c) a vinyl aromatic hydrocarbon as a main component.
At least one of which is at the end of the copolymer chain, and has a tapered distribution structure in which the amount of the conjugated diene gradually decreases from the end of the copolymer chain, and (d) the block copolymer is linear. Provided is a bituminous modifier having a shape-like structure. Further, according to the present invention, there is provided a bitumen composition characterized by containing bitumen and the above-mentioned bitumen modifier.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. Block Copolymer The block copolymer used in the present invention is a polymer containing a vinyl aromatic hydrocarbon-based polymer block (A) as at least one, and preferably two or more, and a conjugated diene-based polymer. It is a block copolymer having at least one block (B). The vinyl aromatic hydrocarbon-based polymer block (A) means that the vinyl aromatic hydrocarbon exceeds 50% by weight, preferably 60 to 100% by weight, more preferably 70 to 100% by weight, and most preferably 80% by weight. ~
A polymer block containing 100% by weight,
A vinyl aromatic hydrocarbon homopolymer or a polymer block composed of a vinyl aromatic hydrocarbon and a conjugated diene. The polymer block (B) containing a conjugated diene as a main component means that the conjugated diene exceeds 50% by weight, preferably 60 to 1
It is a polymer block containing 00% by weight, more preferably 70 to 100% by weight, and most preferably 80 to 100% by weight, and is composed of a conjugated diene homopolymer or a conjugated diene and a vinyl aromatic hydrocarbon. It is a polymer block.

The block copolymer used in the present invention has a linear structure, and preferably has a structure represented by the following general formulas (A) to (C). (A) (A-B) _m (B) (A-B) _n- A (C) (A-B) ₂ -X In these general formulas, A is a heavy chain mainly composed of vinyl aromatic hydrocarbon. It is a united block (A), and B is a polymer block (B) mainly containing a conjugated diene. X
Is the residue of a bifunctional coupling agent. m and n are
Each is an integer of 1 or more.

When the block copolymer does not have a linear structure, a sufficient modifying effect cannot be obtained even if other requirements such as weight average molecular weight are satisfied. For example, a block copolymer having a branched structure obtained by coupling with a trifunctional or higher functional coupling agent is inferior in solubility to bitumen and has an effect of improving softening point and fluidity. This is not sufficient, and in particular when mixed with bitumen, aggregate, etc. by the plant mix method, a bituminous composition exhibiting satisfactory fluidity resistance cannot be obtained.

The block copolymer used in the present invention has at least one polymer block (A) at the end of the copolymer chain and is a copolymer of vinyl aromatic hydrocarbon and conjugated diene. It is necessary that the copolymer block has a tapered distribution structure in which the content of the conjugated diene in the copolymer block gradually decreases from the end of the copolymer chain.
For example, in the case of the linear block copolymers represented by the above general formulas (A) to (C), at least one of the blocks A is located at the copolymer chain terminal, and the vinyl aromatic hydrocarbon and the conjugated diene And a conjugated diene is distributed in a taper shape at the end of the copolymer block.

At least one block A (hereinafter, also referred to as "taper block portion") having such a tapered distribution structure at the end is sufficient, but it is at both ends of the copolymer chain. It doesn't matter. Further, when the block copolymer does not have a tapered block portion of a conjugated diene at the terminal, the solubility in bitumen is poor, and a sufficient improvement effect can be obtained with respect to the penetration and flow resistance of the bitumen composition. Absent.

The content of conjugated diene used to form the tapered block portion is less than 50% by weight of the total monomers forming the block, preferably 1-40% by weight, more preferably 3-30% by weight, most preferably Is in the range of 5 to 25% by weight. If the conjugated diene content in the taper block portion is too small, the solubility in bitumen will be poor, and conversely, if it is too large, the toughness and tenacity of the bitumen composition will not be sufficient, either of which is not preferable.

The block copolymer used in the present invention has a polystyrene-equivalent weight average molecular weight of 20 measured by gel permeation chromatography (GPC).
20,000 to 1,000,000 (20 to 1 million),
It is preferably 200,000 to 700,000, more preferably 250,000 to 500,000, and most preferably 300,000 to 400,000. If the weight average molecular weight of the block copolymer is too small, the fluidity resistance and the softening point are not sufficiently improved. Conversely, if the weight average molecular weight is too large, the solubility in bitumen is poor and the physical properties of the bitumen composition are also improved. It is not sufficient and neither is preferable.

The composition ratio of the vinyl aromatic hydrocarbon and the conjugated diene in the block copolymer used in the present invention is 5:95 to 60:40, preferably 10: 9, by weight.
0 to 50:50, more preferably 15:85 to 45: 5
The range is 5. If the vinyl aromatic hydrocarbon content is too low, the toughness and tenacity are not sufficient, and on the contrary, if the vinyl aromatic content is too high, the softening point of the bituminous composition is lowered, and the fluidity resistance in the summer is insufficient. Neither is preferable.

The amount of vinyl bond in the conjugated diene moiety of the block copolymer used in the present invention is not particularly limited, but is usually 90% or less, preferably 1 to 60%, more preferably 5 to 30%. Is. When the vinyl bond amount is excessively large, the penetration of the bitumen composition tends to be lowered.

The block copolymer used in the present invention is produced by a known method, for example, by polymerizing an aromatic hydrocarbon and a conjugated diene using an organolithium compound as an initiator in a hydrocarbon solvent. be able to.
At the time of polymerization, a polar compound can be used for the purpose of adjusting the reactivity ratio of vinyl aromatic hydrocarbon and conjugated diene, changing the microstructure of the polymerized butadiene portion, adjusting the polymerization rate, and the like. The formation of the tapered block portion of the distribution structure in which the conjugated diene content gradually decreases from the copolymer chain end can be achieved, for example, by adding a polar compound to a hydrocarbon solvent and using an organolithium compound as an initiator, during polymerization, ( 1) A mixture of a predetermined amount of a conjugated diene and a vinyl aromatic hydrocarbon is polymerized, and after the polymerization reaction is substantially completed, (2) The remaining conjugated diene is polymerized, and (3) Furthermore, the remaining vinyl aromatic. A block copolymer of A ₁ -B-A ₂ type obtained by polymerizing a group hydrocarbon, wherein the terminal block A ₁ formed in the first polymerization step has a distribution structure in which the conjugated diene content gradually decreases from the terminal. The block copolymer having the above can be obtained. This makes use of the fact that the reactivity of conjugated dienes is higher than that of vinyl aromatic hydrocarbons.

Examples of vinyl aromatic hydrocarbons include:
Styrene, α-methylstyrene, p-methylstyrene,
Examples include vinyltoluene and vinylnaphthalene.
Of these, styrene is particularly preferable. The vinyl aromatic hydrocarbons may be used alone or in combination of two or more. Examples of the conjugated diene include 1,3-butadiene, isoprene, and 1,3.
-Pentadiene, 2,3-dimethyl-1,3-butadiene, 1,3-hexadiene and the like. Among these, 1,3-butadiene and isoprene are preferable, and 1,3-butadiene is particularly preferable. The conjugated dienes can be used alone or in combination of two or more.

As the hydrocarbon solvent used for producing the block copolymer, for example, aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane, isooctane; cyclopentane, methylcyclopentane, cyclohexane, Methylcyclohexane,
Examples thereof include alicyclic hydrocarbons such as ethylcyclohexane; aromatic hydrocarbons such as benzene, ethylbenzene, xylene; and the like, and these may be used alone or in admixture of two or more. The amount of the hydrocarbon solvent used is usually in the range of 1 to 50% by weight of the monomer concentration.

Examples of polar compounds include ethers such as tetrahydrofuran, diethyl ether, anisole, dimethoxybenzene and ethylene glycol dimethyl ether; amines such as triethylamine, tetramethylenediamine, N-dimethylaniline and pyridine;
Examples thereof include thioethers, phosphines, phosphoramides, alkylbenzene sulfonic acids, and alkoxides such as potassium and sodium, which are appropriately selected depending on the required performance. The amount of the polar compound used is appropriately determined according to the kind of the compound and the required properties, but is usually 0.001 to 1 mol, preferably 0.01 to 0.5 mol per 1 mol of the organolithium compound. Is.

An organic monolithium compound or the like is used as the organic lithium compound, and specific examples include, for example,
n-butyllithium, sec-butyllithium, ter
t-butyllithium, n-hexyllithium, iso-
Hexyl lithium, phenyl lithium, naphthyl lithium and the like can be mentioned. These may be used alone or in admixture of two or more. The amount of organolithium compound used is
The weight average molecular weight of the target block copolymer and the kind of the organolithium compound are appropriately selected. For example, in the case of n-butyllithium, the total amount of monomers is 10
It is usually 0.001 to 1 part by weight, preferably 0.01 to 0.1 part by weight, per 0 part by weight.

The polymerization reaction may be an isothermal reaction or an adiabatic reaction, and is usually 0 to 150 ° C., preferably 20 to 12
It is carried out in the polymerization temperature range of 0 ° C. As the block copolymer, it is also possible to use a block copolymer which is subjected to a coupling reaction by adding a bifunctional coupling agent after the above polymerization reaction. Two
Examples of the functional coupling agent include dihalogenated hydrocarbons such as dibromobenzene, dichlorobenzene, dibromoethylene; dimethyldichlorosilane, dicyclohexyldichlorosilane, diphenyldichlorosilane,
Dihalogenated metals such as dimethyldichlorotin and dimethyldichlorogermanium; dialkoxy metals such as dimethyldimethoxysilane, diethyldimethoxysilane and diethyldimethoxytin; esters such as methyl acetate, ethyl acetate, methyl benzoate and phenyl benzoate; Etc. Among these, dihalogenated hydrocarbons, dihalogenated metals, dialkoxy metals and the like are preferable. The coupling rate is appropriately selected depending on the use and characteristics, but is usually 50% or more, preferably 60%.
-100%, more preferably 80-100%. Two
The amount of the functional coupling agent used is, for example, usually 0.25 to 2 mol, preferably 0.30 to 1 mol, and more preferably 0.35 per 1 mol of the organic monolithium compound.
~ 0.5 mol. The coupling reaction is usually 0 to
It is performed at 150 ° C. for 0.1 to 20 hours.

Optional Components In the present invention, the above-mentioned specific block copolymer is used as a bitumen modifier, but if necessary, a softening agent, an anti-blocking agent, etc. may be added as long as the intended purpose is not impaired. It can be added. Examples of the softening agent include petroleum-based softening agents (aromatic oils, naphthene-based oils, paraffin-based oils, etc.), paraffins, vegetable oil-based softening agents, plasticizers, and the like. The amount of the softening agent used is usually 0 to 200 parts by weight, preferably 20 to 150 parts by weight, per 100 parts by weight of the block copolymer.

Examples of the anti-blocking agent include talc, calcium carbonate, clay, silica, barium sulfate and the like. The amount of the anti-blocking agent used is usually 0 to 50 parts by weight per 100 parts by weight of the block copolymer,
It is preferably 0.1 to 20 parts by weight.

The block copolymer of the present invention may further contain, if necessary, an antioxidant such as a hindered phenol type, a sulfur type or a phosphoric acid type; an ultraviolet absorber such as a benzophenone type; a light stabilizer such as a hindered amine type. Rubbers such as natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, chloroprene rubber, acrylic rubber, isoprene-isobutyl rubber; thermoplastic elastomers such as block copolymers other than the product of the present invention; Thermoplastic resins such as ethylene ethyl acrylate copolymer and ethylene-vinyl acetate copolymer; and the like can be added.

The bitumen modifier of the present invention is the above-mentioned specific block copolymer alone, or the block copolymer containing various additives if desired. The shape of the bituminous modifier is not particularly limited, but it is generally used as powder, pellets, porous pellets, latex and the like. For the plant mix, a powder having a particle size of 1000 μm or less is particularly preferable.

[0028] Examples of the 瀝blue bitumen, the present invention is not particularly limited, conventional asphalt, for example, straight asphalt, semi-blown asphalt, blown asphalt, asphalt emulsions and tar, pitch, cut back asphalt, such as the addition of oil, playback Asphalt can be used. These can be used alone or in combination of two or more. The bitumen may be decolorized asphalt or the like.

Bitumen Composition The bitumen modifier of the present invention is, as described above, a specific block copolymer alone or a mixture of the block copolymer with various additives as desired. The bitumen composition of the present invention contains bitumen and a specific bitumen modifier as essential components. Primarily, a bituminous composition containing bitumen and a bituminous modifier has properties as a binder. A bituminous composition in which an additive such as an aggregate is further mixed with a bitumen and a bitumen modifier is used as a road paving material or the like.

The method for preparing the bitumen composition of the present invention is not particularly limited.
A method of heating, melting and kneading with a wet mill, a high shear mixer, a roll, a kneader, a Banbury mixer, an extruder or the like can be adopted. The blending ratio of the bituminous modifier varies depending on the purpose of use and the type of bitumen.
It is usually 0.01 to 100 parts by weight, preferably 0.1 to 50 parts by weight, and more preferably 1 to 20 parts by weight per part by weight.

The additives to be added to the bituminous composition include
There is no particular limitation, and it is appropriately selected from additives commonly used in bitumen compositions. Specific examples of the additive include aggregates such as crushed stone, crushed stone, gravel, sand and recycled aggregate; fillers such as stone powder, talc and calcium carbonate; antistripping agents such as slaked lime, amines and amides; methylcellulose, Fibrous reinforcing agents such as polyvinyl alcohol; elasticity improvers,
Use of viscosity reducers, viscosity improvers, fillers, pigments, softeners, tackifiers, antioxidants, UV absorbers, light stabilizers, rubbers, other thermoplastic elastomers, thermoplastic resins, etc. You can

When the bituminous composition of the present invention is used for road paving, it is usually used as a bituminous mixture by mixing an aggregate and a filler (hereinafter, both are referred to as "aggregates"). As aggregate and filler, for dense particle size, fine particle size or coarse particle size mixture used for general road pavement, or for open particle size mixture used for water permeable pavement, drainage pavement, sound absorbing pavement, etc. Aggregates and fillers such as are used. The composition of the bitumen mixture is usually 98-aggregate.
It is 85% by weight and 2 to 15% by weight of bitumen. The bitumen modifier is usually used within the range of the above blending ratio with respect to the bitumen. The above-mentioned additives can be added to the bitumen mixture, if necessary.

The mixing method is not particularly limited, and a premixing method of kneading a bituminous composition containing a bitumen and a bituminous modifier prepared in advance and an aggregate, a bituminous modifier, a bitumen, and an aggregate. The plant mix method of kneading can be adopted. As the plant mix method, for example, (a) a method in which a filler, a heated aggregate, and a heated bitumen are kneaded in advance, and then a bituminous modifier is added and kneaded, (b)
A method of simultaneously kneading a filler, a heated aggregate, a heated bitumen, and a bituminous modifier, (c) a method of previously kneading a filler, a heated aggregate, and a bituminous modifier, and then adding heated bitumen and kneading There is.

[0034]

EXAMPLES The present invention will be more specifically described below with reference to production examples, examples and comparative examples, but the present invention is not limited to these examples. Parts and% in these examples are by weight unless otherwise specified.

The methods for measuring physical properties are as follows. (1) Weight average molecular weight The weight average molecular weight of the block copolymer was measured as a standard polystyrene conversion amount according to the gel permeation chromatography (GPC) method. As a measuring device,
Toso-made HPLC was used. Column is G4000
One HXL and one G5000HXL were used. (2) Amount of bound styrene The amount of bound styrene (% by weight) of the block copolymer was calculated by the Hampton method using an infrared spectrophotometer (manufactured by JASCO Corporation). (3) Solubility The solubility of the bituminous modifier in bitumen is the asphalt heated to 180 ° C according to the "Preparation of modified asphalt sample" method described in the Handbook of Pavement Testing Methods established by the Japan Road Association. The block copolymer was added to and stirred, and the time (hr) until there was no undissolved material was determined. (4) Penetration and softening point Penetration (1/10 mm) and softening point (° C) of the bituminous composition
Was measured according to JIS K2207. (5) Toughness and tenacity The toughness (kgf · cm) and tenacity (kgf · cm) of the bituminous composition were measured according to the method described in “Handbook of Pavement Test Methods” edited by the Japan Road Association. (6) Flow resistance The flow resistance of the bituminous mixture was determined by performing a wheel tracking test according to the method described in "Handbook of Pavement Test Methods" edited by the Japan Road Association to determine the dynamic stability (times / mm). Calculated.

[Production Example 1] (Production of block copolymer) A 15-liter stainless steel reaction vessel equipped with a jacket and a stirrer was sufficiently replaced with nitrogen, and then 6 kg of cyclohexane and styrene as a monomer for the first stage polymerization. 200 g
40 g of butadiene, and 0.05 mol of n-butyllithium to which tetramethylethylenediamine was added later were charged, and warm water was passed through the jacket to adjust the content to 60 ° C. Then, 6 ml of a cyclohexane solution containing 10 mmol of n-butyllithium was added to initiate polymerization.
The temperature was raised to 80 ° C. at a rate of 1 ° C./min to proceed the polymerization reaction. After the completion of the first-stage polymerization, 1560 g of butadiene was added as a monomer for the second-stage polymerization to continue the polymerization until almost complete polymerization, and then 200 g of styrene was further added as a monomer for the third-stage polymerization. Similarly, almost completely polymerized. After the completion of the polymerization, methanol was added in an amount twice that of n-butyllithium, and the mixture was stirred for 10 minutes. The contents were removed from the reactor and 2,6-di-t-butylphenol 1
After the addition of 0 g, the solvent was removed by steam stripping and vacuum drying, and the powder was pulverized to obtain a block copolymer A which passed through a 20-mesh sieve. Table 1 shows the bound styrene amount and weight average molecular weight of the block copolymer A. The block copolymers B to I were obtained by carrying out a polymerization reaction in the same manner as described above (the method of Production Example 1) according to the preparation recipe shown in Table 1. Table 1 shows the amount of bound styrene and the weight average molecular weight of each block copolymer.

[Production Example 2] (Production of Branched Block Copolymer) Each of the monomers and the initiator described in the column "J" of the polymer in Table 1 was charged and the polymerization of styrene in the third stage was carried out. Polymerization was performed in the same manner as in Production Example 1 except that 4.6 mol of tetramethoxysilane, which is a polyfunctional coupling agent, was added and the coupling reaction was performed for 30 minutes after the completion of the second-stage polymerization. , Block copolymer J was obtained. Table 1 shows the amount of bound styrene and the weight average molecular weight of the block copolymer J.

[0038]

[Table 1] (Footnote) (* 1) Taper amount = [(First stage butadiene amount) / (1
First-stage styrene amount + first-stage butadiene amount)] × 100
(%) (* 2) Branched block copolymer

[Examples 1 to 3 and Comparative Examples 1 and 2] Binder Property Test 4 parts of each of block copolymers A, B, C, G, and J shown in Table 1 were placed in a 1-liter glass container. Each binder was prepared by adding to 96 parts of straight asphalt (60/80) heated to 180 ° C. and continuing stirring until completely dissolved. Measure the properties of each obtained binder,
The results are shown in Table 2. Mixture property test Also, aggregates for dense-grained asphalt mixture preheated to 180 ° C (composition: No. 6 crushed stone 43 wt%, No. 7 crushed stone 14
% By weight, 38% by weight of sand, 5% by weight of stone powder) 94.8 parts were kneaded in a pug mill mixer for 30 seconds, and then 1
Straight asphalt heated to 50 ° C (60/8
0) 4.99 parts were added and mixed for 1 minute, 0.21 parts of each block copolymer was added, and further mixed for 1 minute. The obtained mixture at 160 ° C. was immediately put in a mold, and a roller compactor was used to draw 2 at a linear pressure of 30 kgf / cm.
It was compacted 5 times (50 times) to obtain a sample. Using this test piece, a wheel tracking test was conducted to measure the dynamic stability, which is a measure of fluidity resistance. The higher the numerical value of this dynamic stability, the better the flow resistance. Table 2 shows the results
It was shown to.

[0040]

[Table 2]

From the results shown in Table 2, the block copolymers A, B and C having a tapered block portion at the end have excellent solubility in bitumen, and the asphalt compositions (binders) containing these block copolymers have excellent solubility. It can be seen that the penetration and softening point are also good, and that the dynamic stability (flow resistance) of the mixture prepared according to the plant mix method is remarkably excellent (Examples 1 to 3). On the other hand, when the block copolymer G having no tapered block portion was used (Comparative Example 1), the solubility, the penetration and the dynamic stability were poor, and the branched block copolymer J was obtained. When used (Comparative Example 2), the solubility is extremely poor and the dynamic stability is poor.

[Examples 4 to 7 and Comparative Example 3] Dynamic stability was obtained in the same manner as in Examples 1 to 3 by using block copolymers D, E, F, H and I having different weight average molecular weights. I asked. The results are shown in Table 3.

[0043]

[Table 3]

From the results shown in Table 3, when a block copolymer having a tapered block portion at the end and a weight average molecular weight of 200,000 or more (2500 to 500,000) was used as a modifier (Examples 4 to 4). 7) has excellent dynamic stability (flow resistance)
You can see that Considering together with the results of Table 2, the weight average molecular weight of the block copolymer is 30 to 40.
It can be seen that the dynamic stability is remarkably excellent at around 10,000. On the other hand, the block copolymer H having a weight average molecular weight of less than 200,000 even if it has a tapered block portion.
When (Comparative Example 3) is used, the dynamic stability is significantly reduced.

[Examples 8 to 9 and Comparative Examples 4 to 5] A bituminous composition was prepared using the block copolymers A, C, G and J, and evaluated as a drainage paving material. In the binder property test, 6 parts of each block copolymer and 94 parts of straight asphalt (60/80) were used. In the mixture property test, 0.282 parts of each block copolymer,
Straight asphalt (60/80) 4.418 parts,
And the same procedure as in Examples 1 to 3 except that 95.3 parts of open-grained aggregates (composition: 89.5% by weight of crushed stone, 5% by weight of sand, 5.5% by weight of stone powder) were used. went. Table 4 shows the results
Shown in

[0046]

[Table 4]

From the results shown in Table 4, when a block copolymer having a tapered block portion at the end was used as the modifier (Examples 8 to 9), the solubility was excellent, the penetration and the softening degree were excellent. It can be seen that the binder properties such as toughness, toughness and tenacity are excellent, and the dynamic stability (flow resistance) is excellent even when used as a drainage pavement material. On the other hand, when the block copolymer G having no tapered block portion was used (Comparative Example 4), both solubility and dynamic stability were poor, and a branched block copolymer was used. In the case (Comparative Example 5), the solubility, toughness, and tenacity were very poor, and the dynamic stability was also insufficient.

[Example 10] Block copolymer F100
37.5 parts of paraffin-based process oil (Diana Process Oil PW-90 manufactured by Idemitsu Kosan Co., Ltd.) was impregnated at room temperature with a stirrer. Except for using 11 parts of this mixture and 89 parts of straight asphalt (60/80), the properties of the binder and the properties of the mixture according to the drainage formulation were examined in the same manner as in Examples 8 to 9. As a result, the dissolution time (1
hr), penetration (53 (1/10 mm)), softening (9
9 ° C), toughness (242 Kgf · cm), tenacity (183 Kgf · cm), and dynamic stability (5,25
It was confirmed to be excellent in 0 times / mm).

Preferred embodiments of the present invention are as follows. (1) The block copolymer has the following general formulas (A) to (C).
The bituminous modifier having the structure shown by. (A) (A-B) _m (B) (A-B) _n- A (C) (A-B) ₂ -X where A is a polymer block (A containing vinyl aromatic hydrocarbon as a main component). ), At least one of which is
It is a polymer block which has a tapered distribution structure at the end of the copolymer chain and in which the amount of conjugated diene gradually decreases from the end of the copolymer chain. B is a polymer block (B) mainly containing a conjugated diene. X is the residue of the bifunctional coupling agent. m and n are each an integer of 1 or more. (2) The bituminous modifier according to the item (1), wherein m is an integer of 2 or more. (3) The bitumen modifier according to the item (1), wherein n is 1.

(4) The bitumen modifier according to (1) above, wherein the bifunctional coupling agent is at least one selected from dihalogenated hydrocarbons, dihalogenated metals and dialkoxy metals. (5) The bitumen modifier, wherein the block copolymer has an A ₁ -BA ₂ type structure. However, A ₁ is a polymer block mainly composed of vinyl aromatic hydrocarbons and having a tapered distribution structure in which the amount of conjugated diene gradually decreases from the end of the copolymer chain, and A ₂ is a vinyl aromatic compound other than that. It is a polymer block mainly composed of hydrocarbons. (6) The bitumen modifier, wherein the block copolymer has an A ₁ -B-X-B-A ₁ type structure. However, A
₁ is a polymer block mainly composed of vinyl aromatic hydrocarbon and having a tapered distribution structure in which the amount of conjugated diene gradually decreases from the end of the copolymer chain.

(7) The composition ratio of the vinyl aromatic hydrocarbon and the conjugated diene in the block copolymer is a weight ratio of preferably 10:90 to 50:50, more preferably 15: 8.
The bituminous modifier of 5 to 45:55. (8) The bituminous modifier, wherein the vinyl aromatic hydrocarbon is styrene and the conjugated diene is 1,3-butadiene. (9) The bitumen modifier, wherein the amount of conjugated diene in the polymer block having a tapered distribution structure in which the amount of conjugated diene gradually decreases is preferably 1 to 40% by weight, more preferably 5 to 25% by weight. (10) The bitumen modifier, wherein the block copolymer has a weight average molecular weight of preferably 250,000 to 500,000, more preferably 300,000 to 400,000.

(11) The block copolymer is A ₁ -B-
It has an A ₂ type or A ₁ -B-X-B-A ₁ type structure, a weight average molecular weight of 300,000 to 400,000, and a content of bound vinyl aromatic hydrocarbons of 15 to 45% by weight. The bitumen modifier, wherein the amount of conjugated diene in the polymer block A ₁ having a tapered distribution structure in which the amount of conjugated diene gradually decreases from the terminal of the copolymer chain is 5 to 25% by weight. (12) The bituminous modifier, wherein the bituminous modifier is obtained by adding at least one additive selected from a softening agent and an antiblocking agent to the block copolymer, if necessary. (13) The bituminous modifier which is a powder. (14) The particle size of the powder is 1000 μm or less (13)
A bituminous modifier as described in the item. (15) A bitumen composition containing bitumen and the above-mentioned bitumen modifier.

(16) With respect to 100 parts by weight of bitumen, 0.01 to 100 parts by weight, preferably 0.1 to 100 parts by weight of the bitumen modifier.
The bituminous composition containing 50 parts by weight, more preferably 1 to 20 parts by weight. (17) A bitumen composition containing bitumen, a bitumen modifier, and aggregates. (18) The bitumen composition according to (17) above, wherein the composition ratio of bitumen to aggregates is 2 to 15% by weight of bitumen and 98 to 85% by weight of aggregates. (19) The above (17) or (18) for road paving
A bituminous composition according to the item. (20) The bitumen composition according to the item (19), which is for drainage pavement. (21) The above (1) prepared by the plant mix method
A bituminous composition according to item 9) or (20).

[0054]

Since the bitumen modifier of the present invention has excellent solubility in bitumen, it can be easily uniformly dispersed in the bitumen by the plant mix method or the like. The bitumen composition obtained by blending the bitumen modifier of the present invention with the bitumen has excellent binder properties such as softening point, penetration, toughness and tenacity. A bitumen composition containing bitumen, a bitumen modifier, and aggregates has excellent fluidity resistance. Therefore, the bituminous composition of the present invention can be used for road pavement, waterproofing, roofing, rust prevention, automobile undercoat, pipe coating, joint material, etc. depending on its composition and characteristics.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaru Shimazaki 1-4-22 Asamadai, Ageo City, Saitama Prefecture (72) Inventor Shusuke Suzuki 6 at 606, Minami Plain, Iwatsuki City, Saitama Prefecture

Claims (2)

[Claims] 1. A block copolymer containing at least one polymer block (A) mainly composed of vinyl aromatic hydrocarbons and at least one polymer block (B) mainly composed of conjugated dienes. A bituminous modifier made of
(A) The block copolymer has a weight average molecular weight of 200,0.
0.001,000,000, and the vinyl aromatic hydrocarbon content of the block copolymer (b) is 5 to 60% by weight.
And (c) at least one of the polymer blocks (A) mainly composed of vinyl aromatic hydrocarbon is at the end of the copolymer chain, and the amount of conjugated diene is gradually reduced from the end of the copolymer chain. And a block copolymer (d) having a linear structure. 2. A bituminous composition comprising bitumen and the bituminous modifier according to claim 1.