JP3310536B2 - Porous crumb comprising hydrogenated block copolymer and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a kneaded molded product which absorbs a softening agent, a plasticizer and the like uniformly and in a short time, has good handling properties after absorbing the same, and has no unmelted material. The present invention relates to a porous crumb comprising a hydrogenated product of a block copolymer having a polymer block mainly composed of a vinyl aromatic compound and a polymer block mainly composed of a conjugated diene, and a method for producing the same.

[0002]

2. Description of the Related Art A hydrogenated product of a block copolymer having a polymer block mainly composed of a vinyl aromatic compound and a polymer block mainly composed of a conjugated diene (hereinafter, abbreviated as a hydrogenated block copolymer) ) Is not only excellent in weather resistance, heat resistance, impact resistance, and flexibility, but also shows the same strength and elastic properties as conventional vulcanized rubber without vulcanization. It is used in a wide range of fields such as components, light electrical components, and various industrial products.

[0003] As a prior document describing a method for producing such a hydrogenated block copolymer, there is Japanese Patent Publication No. 42-8 / 1972.
No. 704, Japanese Patent Publication No. 42-8933, Japanese Patent Publication No. Sho 4
JP-A-3-6636, JP-B-48-3555, JP-B-46-7291 and the like.

[0004] Such a hydrogenated block copolymer is usually produced by polymerizing a vinyl aromatic compound and a conjugated diene in a hydrocarbon solvent and hydrogenating the obtained block copolymer. At this time, since the hydrogenated block copolymer is uniformly dissolved in the solvent or obtained in a suspended state, it is necessary to separate and recover the hydrogenated block copolymer from the hydrocarbon solvent. Become. Various methods are known for separating and recovering the hydrogenated block copolymer from the hydrocarbon solvent, one of which is described in JP-B-57-47684 and JP-B-57-53363. The steam stripping method of injecting a hydrocarbon solvent solution of a hydrogenated block copolymer into hot water and evaporating the solvent together with water vapor to precipitate a crumb-like hydrogenated block copolymer as described above is known. Are known.

[0005]

However, the crumb-like hydrogenated block copolymer obtained by such a steam stripping method has (a) a moderately large pore diameter, but the total pore volume is small. Too small, or because the ratio of pores having a specific range of pore diameter to the entire pores is too small, it is not possible to uniformly and quickly absorb softeners, plasticizers, etc., or (b) pore diameter Because of its large and low bulk density, it has poor handling properties after absorbing softeners, plasticizers, etc., and when producing compounds with resins such as polypropylene and polyethylene, unmelted materials may increase. Has problems.

The present invention has been made in view of the above-mentioned problems of the prior art, and is intended to uniformly and quickly absorb a softener, a plasticizer, etc., to have good handleability, and to provide an unmelted material. It is an object of the present invention to provide a porous crumb made of a hydrogenated block copolymer, which has excellent properties such as providing a kneaded molded product free from cracks, and a method for producing the same.

[0007]

According to the present invention, in order to solve the problems], one of the above problems, organic <br/> a polymer block composed mainly of polymer block and a conjugated diene mainly of a vinyl aromatic compound And the weight ratio of the vinyl aromatic compound to the conjugated diene is 5 /
It is composed of a hydrogenated block copolymer obtained by hydrogenating at least 50% of an unsaturated bond based on a conjugated diene of a block copolymer in the range of 95 to 95/5, and has a bulk density of 0.18 g / cc. As described above, the total volume of the pores is 0.4 cc / g.
This is achieved by providing a porous crumb characterized in that the total volume of pores having a pore diameter in the range of 0.14 to 3.9 μm is at least 8% of the total volume of the pores. Is done.

[0008] Also, according to the present invention, one of the other above-described problems is to have a polymer block composed mainly of polymer block and a conjugated diene mainly of a vinyl aromatic compounds, vinyl aromatic compounds And the conjugated diene in a weight ratio of 5/95 to
The hydrogenated block copolymer obtained by hydrogenating 50% or more of the unsaturated bond based on the conjugated diene of the block copolymer in the range of 95/5 has a polymer concentration of 5 to 60% by weight. A certain hydrocarbon solvent solution is supplied to hot water while being heated to 40 to 150 ° C., and the boiling point of the hydrocarbon solvent or, if the hydrocarbon solvent and water azeotrope, at least the azeotropic temperature, 150 ° C. This is attained by providing a method for producing the above-mentioned porous crumb, which is characterized by performing steam stripping at the following temperature.

[0009] The porous crumbs of the present invention, have a polymer block composed mainly of polymer block and a conjugated diene mainly of a vinyl aromatic compound, the weight ratio of the vinyl aromatic compound and a conjugated diene is 5 / 95-95 / 5, preferably 1
50% or more of the unsaturated bonds based on the conjugated diene of the block copolymer in the range of 0/90 to 90/10 are composed of a hydrogenated hydrogenated block copolymer. Here, if the weight ratio of the vinyl aromatic compound and the conjugated diene constituting the block copolymer deviates from the range of 5/95 to 95/5, in the production process of the porous crumb composed of the hydrogenated block copolymer, Blocking between crumbs is likely to occur. On the other hand, if the hydrogenation ratio deviates from the above range, the heat resistance of the hydrogenated block copolymer is poor, and thermal decomposition of the hydrogenated block copolymer occurs during the production of the porous crumb,
This may cause coloring of the crumbs and adhesion to the production equipment.

The basic skeleton of such a hydrogenated block copolymer is, for example, a compound represented by the general formula (AB) _k or (ABA) _k (where A is a polymer comprising a vinyl aromatic compound) Represents a block, B represents a polymer block composed of a conjugated diene such as isoprene, butadiene, etc., and k is an integer of 1 to 5) or [(AB) _n −] _mx , [(BA) _n- ] _mX , [(ABA) _n- ] _mx , [(BA) _n- ] _mx (where A and B are as defined above, and X is tetrachloride Residues of coupling agents such as silicon, tin tetrachloride, polyhalogenated hydrocarbons, carboxylic esters such as phenyl benzoate or vinyl compounds such as divinylbenzene, or residues of initiators such as polyfunctional organolithium compounds And m and n are integers of 1 or more.) It can be.

In the present invention, the vinyl aromatic compound forming the hydrogenated block copolymer includes, for example,
Styrene, o- or p-methylstyrene, p-te
rt-butylstyrene, 1,3-dimethylstyrene, α
-Methylstyrene, vinylnaphthalene, vinylanthracene, etc., and styrene is particularly preferably used. The vinyl aromatic compound may be used alone or in combination of two or more.

On the other hand, examples of the conjugated diene include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. 1,3-butadiene or isoprene is used. The conjugated diene may be used alone or in combination of two or more.

Further, the hydrogenated block copolymer may have a functional group at at least one molecular chain terminal of the polymer. The functional group referred to here is a carboxyl group, a carbonyl group, a thiocarbonyl group, an acid anhydride group, a thiocarboxyl group, an aldehyde group, a thioaldehyde group, a carboxylic acid ester group, an amide group, a sulfonic acid group, a sulfonic acid ester group. , Phosphate group, phosphate group, amino group, imino group, nitrile group, epoxy group, epithio group, sulfide group, isocyanate group, silicon halide group, hydroxyl group, etc., nitrogen, oxygen, silicon, phosphorus, sulfur, It means an atomic group containing at least one kind of atom such as tin.

Such a hydrogenated block copolymer can be produced by a known method such as an anionic polymerization method or a cationic polymerization method. If the production method is specifically shown, a block copolymer is formed by sequentially polymerizing a vinyl aromatic compound and a conjugated diene in a hydrocarbon solvent using an organic lithium compound as a polymerization initiator, and then forming the block copolymer with hydrogen. An example of the method of addition is given.

The hydrocarbon solvent used at this time includes, for example, aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane and isooctane; cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethyl Alicyclic hydrocarbons such as cyclohexane; and aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene. These may be used alone or in combination of two or more.

As the organic lithium compound used as the polymerization initiator, a lithium compound having one or more lithium atoms in one molecule is used. For example, ethyl lithium, n-propyl lithium, isopropyl lithium, n-lithium Butyllithium, sec-butyllithium, t
tert-butyl lithium, hexamethylene dilithium,
Butadienyldilithium, isoprenyldilithium and the like. The organolithium compounds may be used alone or in combination of two or more.

In the polymerization, the polymerization rate is adjusted, the microstructure (cis, trans, vinyl bond content, etc.) of the polymer block composed of the conjugated diene is adjusted, and the reactivity ratio between the vinyl aromatic compound and the conjugated diene is adjusted. For the purpose, a randomizing agent can be used. Examples of the randomizing agent include ether compounds such as dimethyl ether, diphenyl ether, tetrahydrofuran, diethylene glycol dimethyl ether and diethylene glycol dibutyl ether; amine compounds such as trimethylamine, triethylamine, tetramethylethylenediamine, and cyclic tertiary amine; triphenylphosphine, hexamethylphosphoramide And the like.

The polymerization time for producing the block copolymer may be any time required for the monomer to polymerize. The polymerization temperature is generally in the range of -10 to 150C, preferably in the range of 40 to 120C.

The number average molecular weight of the thus obtained block copolymer before hydrogenation is generally from 5,000 to 1,500,
000, preferably between 10,000 and 50.
It is in the range of 0000.

The obtained block copolymer is prepared according to a known method described in, for example, JP-B-42-8704, JP-B-42-8933, and JP-B-43-6636. Hydrogenation is performed so that 50% or more, preferably 80% or more, of the unsaturated bond based on the conjugated diene of the copolymer is saturated. For hydrogenation of the block copolymer, it is preferable to use the same hydrocarbon solvent as used in the polymerization. Examples of the hydrogenation catalyst include a supported heterogeneous catalyst in which a metal such as Ni, Pt, Pd, and Ru is supported on a carrier such as carbon, silica, alumina, and diatomaceous earth, or Ni, Co, Fe, and Cr. A Ziegler-type homogeneous catalyst obtained by combining an organic acid salt of the above with a reducing agent such as an organic aluminum can be used.

By such hydrogenation, the hydrogenated block copolymer can be obtained in the form of a solution dissolved in a hydrocarbon solvent.

The porous crumb of the present invention has a bulk density of 0.1
8 g / cc or more, the total volume of the pores is 0.4 cc / g or more, and the total volume of the pores having a pore diameter in the range of 0.14 to 3.9 μm is at least 8% of the total pore volume. It is necessary to be.

The bulk density of the porous crumb is 0.18 g / cc
If it is less than 30, handling properties after absorbing a softener, a plasticizer and the like are poor. The bulk density is preferably 0.20 g / cc or more. Also, the total volume of the pores is 0.4 cc /
When the amount is less than g, a sufficient amount of a softener or a plasticizer cannot be absorbed, which is not preferable. Regarding the distribution of pore diameters, when the sum of the volumes of pores having pore diameters in the range of 0.14 to 3.9 μm is outside the above range, a softener,
It is not preferable because a plasticizer or the like cannot be absorbed uniformly and in a short time.

The porous crumb provided by the present invention preferably contains particles belonging to a particle size range of 0.2 to 5 mm in a proportion of 90% by weight or more based on all the particles. If the proportion of particles having a particle size smaller than 0.2 mm is too large, handling of the crumb becomes inconvenient, and dust is generated during use, which tends to cause a problem of deteriorating the working environment. On the other hand, if the proportion of particles having a particle size larger than 5 mm is too large, the processability in mechanically processing the crumb with a kneader or the like may be deteriorated.

Such a porous crumb can be obtained by subjecting a solution of the hydrogenated block copolymer obtained by the above method or the like to a hydrocarbon solvent to be subjected to steam stripping under specific conditions. What is important in the steam stripping treatment is that the polymer concentration in the hydrocarbon solvent solution of the hydrogenated block copolymer is 5 to 60% by weight,
It is preferably adjusted within the range of 10 to 50% by weight, and the solution of the hydrogenated block copolymer in a hydrocarbon solvent is heated to 40 to 150 ° C.
Into a hot water while being heated to a temperature above, and steam stripping at a boiling point of the hydrocarbon solvent, or, when the hydrocarbon solvent and water are azeotropic, at a temperature not lower than the azeotropic temperature and not higher than 150 ° C. It is.

When the polymer concentration is less than 5% by weight, the solvent removal efficiency is poor due to the large amount of the solvent relative to the hydrogenated block copolymer, which is disadvantageous in the production cost. On the other hand, when the polymer concentration exceeds 60% by weight, the viscosity of the solution becomes too high and the fluidity deteriorates, which tends to cause troubles such as clogging in the process. When the polymer concentration is less than 5% by weight, a one-stage or multi-stage flash tank, a stirring tank,
The concentration may be adjusted using a concentrator selected from a type such as a thin film evaporator.
In the case of exceeding, the concentration may be adjusted by diluting with a hydrocarbon solvent.

The temperature of the hydrocarbon solvent solution of the hydrogenated block copolymer to be supplied to the steam stripping step is 40 ° C.
When it is less than 1, a porous crumb can be obtained, but the bulk density of the crumb after drying is low, and the handling property after absorbing a softener, a plasticizer and the like is poor. Further, when the temperature of the hydrocarbon solvent solution of the hydrogenated block copolymer to be supplied to the steam stripping step exceeds 150 ° C., the total volume of pores of the obtained crumb becomes small, and the absorption amount of the softener, plasticizer, etc. Will decrease.

The hot water used in the present invention generally has a temperature range of 80 to 130 ° C., preferably 100 to 120 ° C.

When the temperature at the time of performing steam stripping is lower than the boiling point of the hydrocarbon solvent or lower than the azeotropic temperature of the hydrocarbon solvent and water, the solvent removal efficiency is poor.
On the other hand, the production cost is disadvantageous. On the other hand, if the temperature exceeds 150 ° C., there is a problem that the obtained crumb is colored, and furthermore, the hydrogenated block copolymer may be decomposed. The temperature for performing steam stripping is usually 90 to 1
It is in the range of 40C, preferably 95-120C.

In the steam stripping step, a surfactant may be added to hot water in the solvent removing tank for the purpose of preventing aggregation of the crumbs. Examples of usable surfactants include various carboxylate surfactants such as soap, N-acylamino acid salt, alkyl ether carboxylate, acylated peptide, etc .; alkyl sulfonates, alkyl benzenes and alkyl naphthalene sulfonates , Sulfosuccinates, α-olefin sulfonates, N-acyl sulfonates, etc .; various sulfonate surfactants; sulfated oils, alkyl sulfates, alkyl ether sulfates, alkyl allyl ether sulfates, alkyl Various sulfate-based surfactants such as amide sulfates; Anionic surfactants such as various phosphate-based surfactants such as alkyl phosphates, alkyl ether phosphates and alkyl allyl ether phosphates; Aliphatic amine salts, aliphatic quaternary ammonium salts, pyridinium salts, imi Various cationic surfactants such as zolinium salts; amphoteric surfactants such as carboxybetaine-type, sulfobetaine-type, aminocarboxylate, imidazoline derivatives, and alkyl and alkyl allyl polyoxyethylene ethers, alkyl allyl formaldehyde condensed polyoxyethylene ethers , Polyoxypropylene-based block copolymers, ether surfactants such as polyoxyethylene polyoxypropylene alkyl ethers; ether ester surfactants such as glycerin ester polyoxyethylene ether, sorbitan ester polyoxyethylene ether and sorbitol ester polyoxyethylene ether Activator: polyethylene glycol fatty acid ester, glycerin ester, polyglycerin ester, sorbitan ester, propylene Examples include ester-type surfactants such as lenglycol esters and sucrose esters, and various nonionic surfactants such as nitrogen-containing surfactants. These surfactants are appropriately selected and used according to the conditions such as the molecular form of the hydrogenated block copolymer, polymerization and hydrogenated solvent.

An inert gas such as nitrogen or argon is injected into the storage tank for the hydrocarbon solvent solution of the hydrogenated block copolymer, and a pressure of 0.1 to 0.3 kg / cm ² is applied. This makes it easier to supply the solution to the steam stripping step.

By the above-mentioned steam stripping step, a slurry in which a porous crumb made of a hydrogenated block copolymer is dispersed in water is obtained. By subjecting the obtained slurry to a drying treatment according to a conventional method, a porous crumb can be obtained. At this time, it is important to set drying conditions that do not adversely affect the pores of the wet crumb obtained in the steam stripping step. For this purpose, for example, the drying process is divided into two, and in the first stage, the crumbs containing water are dehydrated by mechanical squeezing to a water content of 1 to 60%, and in the second stage, the crumbs are dried by heating and drying. It is preferable to adopt a method of reducing the rate to less than 1%.

Specifically, in the first stage of the dehydration step, the crumb in a water-containing state is dehydrated by a compression dehydrator such as a roll, a Banbury type dehydrator, a screw extruder type squeezing dehydrator or a centrifugal separator. At this stage, it is desired that the water content be 1 to 60%, preferably 3 to 30%. If the water content exceeds 60% at this stage, the amount of water to be dried in the next second stage becomes extremely large, which is not desirable in terms of production cost. Further, if the water content is less than 1% at this stage, it is not preferable because the time required for the dehydration treatment becomes too long or the crumb is deteriorated by the shearing force of the dehydrator.

In the second stage, the crumb obtained in the first stage is dried until the moisture content is less than 1%. 1% moisture content
In the case described above, problems such as foaming occur when the obtained porous crumb is molded alone or blended with another resin. Examples of the apparatus used for drying include a screw extrusion type drier, a kneader type drier, an expander drier, a hot air drier and a plate drier.

The porous crumb comprising the hydrogenated block copolymer provided by the present invention can be added with various additives depending on the purpose of use. Examples of additives include, for example, softeners such as oils, plasticizers, antistatic agents,
Examples include a lubricant, an ultraviolet absorber, a flame retardant, a pigment, a dye, an inorganic filler, an organic fiber, an inorganic fiber, and carbon black. In addition, various thermoplastic resins can be blended. Examples thereof include olefin resins such as polypropylene, polyethylene, ethylene-vinyl acetate copolymer (EVAc), and ethylene-vinyl alcohol copolymer (EVOH). ; Polyethylene terephthalate (PE
T), polyesters such as polybutylene terephthalate (PBT) and polyethylene naphthalate (PEN); aliphatic polyamides such as nylon 6, nylon 66 and nylon 12, or semi-aromatic polyamides composed of terephthalic acid and various aliphatic diamines, ABS Resin, AES resin, polypropylene oxide (PPO), styrene resin and the like.

The kneading of these additives or the thermoplastic resin with the porous crumb of the present invention is generally carried out by mechanically melting and kneading using a kneading machine used for kneading ordinary thermoplastic resins. is there. Examples of the kneading machine include a single-screw extruder, a twin-screw extruder, a Banbury mixer, and a two-roll extruder.

The porous crumb provided by the present invention has a bulk density of 0.18 g / cc or more, a total volume of pores of 0.4 cc / g or more, and a pore diameter of 0.14 to 0.14 g / cc.
Since the total volume of the pores in the range of 3.9 μm is 8% or more of the total volume of the pores, the softener, the plasticizer, and the like are absorbed uniformly and in a short time, and the handling after absorbing these. It has excellent properties to give a kneaded molded product with good properties and no unmelted material, sheet, film, injection molded product, hollow molded product, pressure molded product, vacuum molded product, extrusion molded product Non-woven fabrics and fibrous materials can be produced by molding into a wide variety of molded products, such as melt blow method and spun bond method, and can also be used as a modifier for various thermoplastic resins. Specific applications include materials for footwear such as sports shoes, leisure shoes, fashion sandals, leather shoes, etc .; materials for adhesives and adhesives used in bookbinding, disposable diapers, etc .; used for road paving materials, waterproof sheets, and pipe coatings. Asphalt modifiers; electric cable materials; televisions, stereos,
Home appliances such as vacuum cleaners; Interior and exterior parts for automobiles such as bumpers, body panels, side seals, etc .; Industrial products; Household goods; Toys; Food packaging materials or food containers such as meat and fresh fish trays, fruit and vegetable packs, and cold food containers. Packaging materials such as daily necessities or industrial materials; laminating agents for fabrics or leather products; elastic materials used for disposable diapers; various rubber products such as hoses, tubes and belts; and medical supplies.

[0038]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

In the examples, parts and percentages are by weight unless otherwise specified. The physical properties of the polymer were measured by the following methods.

(Molecular Weight) A solution of the polymer in tetrahydrofuran was prepared, and measured at 25 ° C. by gel permeation chromatography (GPC) to determine the number average molecular weight (Mn) in terms of polystyrene. (Styrene content) Infrared spectrometer (IR)
The infrared absorption spectrum of the polymer was measured by using the method described above, and the styrene content in the polymer was determined in comparison with a calibration curve prepared based on the infrared absorption spectrum of a sample whose styrene content was known in advance. (Hydrogenation ratio) After dissolving the polymer in chloroform, the iodine value was measured with potassium iodide, and the hydrogenation ratio was calculated.

(Bulk bulk density) 20 g of dried crumb having a water content of 1% or less was packed in a 200 ml measuring cylinder, and the measuring cylinder was naturally dropped five times from a height of 3 cm, and the crumb volume at that time was measured. The density was calculated. For example, when the crumb volume is 100 ml, the bulk density is 0.20.
The bulk density is 0.25 g / cc for g / cc and a crumb volume of 80 ml.

(Pore Volume and Pore Distribution of Crumb) Measured by a mercury porosimetry using a mercury porosimeter [micromeritics type autopore (manufactured by Shimadzu Corporation)].

(Oil absorption) 20 g of dried crumb
In a 10 cm × 10 cm bag made of 200-mesh filtration cloth made of nylon filament, and placed in a large amount of paraffin-based process oil (trade name: Diana Process Oil PW-90, manufactured by Idemitsu Petrochemical Co., Ltd.). After immersion for 30 minutes and 30 minutes, in each case, the bag was pulled up and cut off the oil for 10 minutes, and the weight was measured to calculate how many times the oil of the crumb absorbed the oil. The oil absorption rate was determined by the oil absorption capacity for 3 minutes, and the oil absorption rate was determined by the oil absorption capacity for 30 minutes.

(Handling Property of Crumb after Absorbing Oil) In the above-mentioned oil absorbing property evaluation, the crumb after oil absorption whose oil absorption capacity was evaluated 30 minutes after oil immersion was placed on a stainless steel plate inclined 60 degrees from a horizontal plane. The crumb was checked for slippage by visual inspection, and it was used as a criterion for judging whether or not the crumb was easily fed to the extruder depending on the magnitude of the slip, and the handling property of the crumb after oil absorption was evaluated. The larger the slip, the better the handling.

Indication of evaluation of handling performance ：: good, ：: normal, ×: bad

(Physical Properties of Molded Product) 100 parts by weight of dried crumb, commercially available polypropylene (MA-3, Mitsubishi Yuka Co., Ltd.)
40 parts by weight) and 100 parts by weight of the above paraffin-based process oil were premixed with a tumbler, and then melt-kneaded at 210 ° C. with a twin-screw extruder to obtain pellets. Using an injection molding machine, the obtained pellet is 10 cm × 10 c.
The molded product was molded into a flat plate having a thickness of 3 mm, and the presence of oil bleed on the surface of the molded product, the remaining unmelted product of the molded product, and the foaming state were visually observed.

Indication of evaluation result of molded product appearance Oil bleed ：: good (not visually recognized) ：: ordinary (slightly recognized) ×: poor (very recognized) Residual unmelted material in molded product ○: none ×: Existence of foaming of molded article ：: good (foaming is not visually recognized)

Further, a test piece was punched out of the above-mentioned molded flat plate, and based on the method described in JIS K6301,
The breaking strength and the breaking elongation were measured. The test piece is JIS
This is a No. 3 dumbbell test piece specified in K6301, having a width of 5 mm and a distance between marked lines of 20 mm. The breaking strength and the breaking elongation were measured at a test speed of 500 mm /
Minutes.

Example 1 A sufficiently dehydrated and dried solution of 800 kg of cyclohexane and a toluene solution of sec-butyl lithium at a concentration of 10% by weight 96 was prepared.
0 g (1.5 mol as sec-butyllithium) was fed to the polymerization reaction tank, and the mixture was stirred at 50 ° C. 30 kg of dehydrated and dried styrene is added to this at 0.5 kg / mi.
n at a feed rate of n
Allowed to react for hours. Next, 140 kg of fully dehydrated and dried isoprene was supplied at a feed rate of 1.0 kg / min, and the mixture was further reacted for 1 hour.
0 kg, and allowed to react for 1 hour, with a number average molecular weight of 20
Thus, 1,000 kg of a cyclohexane solution of a styrene-isoprene-styrene triblock copolymer having a styrene content of 30% by weight (hereinafter, styrene-isoprene-styrene triblock copolymer is abbreviated as SIS) was obtained.
The concentration of SIS was 20% by weight.

In this SIS cyclohexane solution, SI
Raney nickel was added in an amount of 0.2% by weight with respect to S, and hydrogenation was performed under a hydrogen pressure of 50 kg / cm ² to obtain a number average molecular weight of 200,000, a styrene content of 29.8% by weight, and a hydrogenation rate. Of hydrogenated SIS (hereinafter, hydrogenated SIS is abbreviated as SEPS) in an amount of 98 mol% was obtained as 1,008 kg of a cyclohexane solution. The concentration of SEPS was 20.6% by weight.

The cyclohexane solution of SEPS was added to 50
℃, 0.15g per 100g of SEPS solution
Hot water (110) in which sodium dodecylbenzenesulfonate (hereinafter abbreviated as DBS)
C.), and steam stripping was performed at 110 ° C. while feeding at a feed rate of 100 kg / hr. The obtained slurry was dehydrated to a water content of 45% using two rolls. During this time, the liquid temperature was adjusted to 110 ± 2 ° C. by steam (the first stage of the drying process). Then 120 ° C
And dried by heating with a plate drier to obtain a dried crumb having a moisture content of 0.1% by weight (second stage of the drying step). Table 1 shows the physical properties of the hydrogenated block copolymer and the conditions employed in the steam stripping step.

The resulting dried crumb has a bulk density of 0.23
g / cc, the total pore volume was 0.80 cc / g, and the total volume of the pores having a pore diameter in the range of 0.14 to 3.9 μm was 15% with respect to the total pore volume. . Table 2 shows the oil absorption capacity after immersing this crumb in oil for 3 minutes and 30 minutes. Table 2 also shows the handling properties of the crumb after absorbing the oil, and the appearance and mechanical performance of a molded product obtained from a compound produced using the crumb.

From these results, it can be seen that the crumb obtained in this example exhibits good oil absorbency, has good handling properties of the crumb after oil absorption, and has a good appearance in the molded product obtained by using this crumb. It shows that it shows physical properties.

Comparative Example 1 A polymerization reaction was carried out in the same manner as in Example 1 except that the heating temperature of the cyclohexane solution of SEPS was set at 20 ° C.
Perform hydrogenation reaction, steam stripping and drying,
A dried crumb was obtained. Table 2 shows various physical properties of the dried crumb and various physical properties of a molded product obtained by using the dried crumb.

The resulting crumb has a low bulk density,
The sum of the volumes of the pores having a pore diameter in the range of 0.14 to 3.9 μm was 6% based on the total pore volume. This dried crumb has a certain level of oil absorption capacity, but is inferior in handleability after oil absorption. Further, the molded product obtained by using this crumb was found to have oil bleed and low breaking strength.

Example 2 A SEPS having a number average molecular weight of 100,000, a styrene content of 25% by weight and a hydrogenation rate of 98 mol% was obtained in the same manner as in Example 1.
Solution in cyclohexane (SEPS concentration: 24% by weight)
1,002 kg were obtained. This cyclohexane solution of SEPS was heated to 80 ° C., supplied to hot water (110 ° C.) containing no surfactant at a feed rate of 100 kg / hr, and subjected to steam stripping at 98 ° C. The obtained slurry was dried in the same manner as in Example 1 to obtain a dried crumb having a water content of 0.1% by weight. This dried crumb has a bulk density of 0.25 g / cc and a total pore volume of 0.7
0 cc / g, and the total volume of the pores having a pore diameter in the range of 0.14 to 3.9 μm was 22% based on the total pore volume. In the same manner as in Example 1, physical properties of this crumb and a molded product obtained by using the crumb were measured. The results are shown in Table 2.

Comparative Example 2 A polymerization reaction, a hydrogenation reaction, steam stripping and drying were carried out in the same manner as in Example 2 except that the heating temperature of the cyclohexane solution of SEPS was 160 ° C. to obtain a dried crumb. Was. The resulting dried crumb had a high bulk density of 0.30 g / cc, but had a total pore volume of 0.3
The total volume of pores having a small pore size of 5 cc / g and a pore diameter in the range of 0.14 to 3.9 μm was 6% with respect to the total pore volume. Table 2 shows various physical properties of the crumb and various physical properties of a molded product obtained by using the crumb. This crumb has a low oil absorption, and a molded product obtained by using this crumb has many unmelted materials, and thus has a drawback of impairing the appearance.

Example 3 In the same manner as in Example 1, hydrogenated styrene having a number average molecular weight of 150,000, a styrene content of 35% by weight, and a hydrogenation rate of 97 mol% was used.
996 k of a cyclohexane solution (SEP concentration: 22% by weight) of an isoprene block copolymer (hereinafter, hydrogenated styrene-isoprene diblock copolymer is abbreviated as SEP)
g was obtained. This cyclohexane solution of SEP was heated to 45 ° C., pressurized with nitrogen to 3.0 kg / cm ² ,
The solution was fed at a feed rate of 100 kg / hr to hot water (110 ° C.) in which DBS was dissolved at a rate of 0.2 g per 100 g of the solution, and steam stripping was performed at 98 ° C. The obtained slurry was dried in the same manner as in Example 1 to obtain a dried crumb having a water content of 0.08% by weight.

This dried crumb has a bulk density of 0.23 g / c.
c, the total pore volume was 0.60 cc / g, and the total volume of pores having pore diameters in the range of 0.14 to 3.9 μm was 21% with respect to the total pore volume. . In the same manner as in Example 1, various physical properties of the crumb and various physical properties of a molded product obtained by using the crumb were measured. The results are shown in Table 2.

Comparative Example 3 A polymerization reaction, hydrogenation reaction, steam stripping and drying were carried out in the same manner as in Example 3 except that the heating temperature of the cyclohexane solution of SEP was 35 ° C. to obtain a dried crumb. Was. The dried crumb has a bulk density of 0.14 g / c
c and the total volume of the pores was 0.78 cc / g, but the total volume of the pores having a pore diameter in the range of 0.14 to 3.9 μm was 4% of the total volume of the pores. Met. Various physical properties of this crumb and various physical properties of a molded product obtained by using this crumb were measured. The results are shown in Table 2. This dried crumb has a certain level of oil absorption capacity, but is inferior in handleability after oil absorption. Further, a molded product obtained by using this crumb was found to have oil bleed and low breaking strength.

[0061]

[Table 1]

[0062]

[Table 2]

[0063]

According to the present invention, the bulk density is 0.18 g /
cc or more, the total volume of the pores is 0.4 cc / g or more,
A porous crumb comprising a specific hydrogenated block copolymer, wherein the total volume of pores having a pore diameter in the range of 0.14 to 3.9 µm is 8% or more of the total volume of the pores, and a method for producing the same Is provided. The porous crumb provided by the present invention absorbs a softener, a plasticizer, etc. uniformly and in a short time,
Moreover, it has excellent handling properties after absorbing these, and provides a kneaded molded article free of unmelted matter.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 6/00-6/28 C08F 8/00-8/50

Claims (2)

(57) [Claims] 1. A and a polymer block composed mainly of polymer block co diene mainly composed of vinyl-aromatic compounds, the weight ratio of the vinyl aromatic compound and a conjugated diene is 5
/ 95 to 95/5, comprising a hydrogenated block copolymer obtained by hydrogenating 50% or more of the unsaturated bonds based on the conjugated diene of the block copolymer, and having a bulk density of 0.18 g / cc or more, the total volume of the pores is 0.4 cc / g
A porous crumb, wherein the total volume of pores having a pore diameter in the range of 0.14 to 3.9 μm is at least 8% of the total pore volume. 2. A and a polymer block composed mainly of polymer block co diene mainly composed of vinyl-aromatic compounds, the weight ratio of the vinyl aromatic compound and a conjugated diene is 5
The polymer concentration of the hydrogenated block copolymer obtained by hydrogenating 50% or more of the unsaturated bond based on the conjugated diene of the block copolymer in the range of / 95 to 95/5 is 5 to 5.
A hydrocarbon solvent solution in the range of 60% by weight is
The mixture is fed into hot water while being heated to 50 ° C., and steam stripped at a boiling point of the hydrocarbon solvent or, when the hydrocarbon solvent and water are azeotropic, at a temperature not lower than the azeotropic temperature and not higher than 150 ° C. multi porous crumbs method of manufacturing according to claim 1, wherein a.