Granules, films, and methods of making granules

Abstract

The present invention provides a kind of granules comprising a block copolymer composition, when it is formed into a film, the generation of fisheye is less, and the tensile elongation is excellent. According to the present invention, a kind of granules is provided, which is composed of a block copolymer composition, the block copolymer composition comprises more than 95% by mass of a linear block copolymer mainly composed of a vinyl aromatic monomer unit and a conjugated diene monomer unit, when the total of the vinyl aromatic monomer unit and the conjugated diene monomer unit in the block copolymer composition is 100% by mass, the content of the conjugated diene monomer unit is 12-27% by mass, in the polystyrene conversion molecular weight when the block copolymer composition is determined by gel permeation chromatography, when the peak molecular weight of the highest one in the peaks with an area ratio of 20% or more relative to the total peak area is taken as the main peak, the peak molecular weight of the main peak is 150-300, and the total area of the peak part in the molecular weight range corresponding to 1.8-2.2 times the peak molecular weight of the main peak is less than 5% of the main peak area.

Description

Technical Field

[0001] This invention relates to particles, films, and a method for manufacturing particles. Background Technology

[0002] Styrene-butadiene block copolymer compositions are widely used in shrink film applications due to their excellent shrinkage properties.

[0003] [Existing Technical Documents]

[0004] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-158241 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In addition to good heat shrinkage, the required properties for shrink films include high elongation and minimal fisheyes. Fisheyes are primarily caused by gel-like foreign matter derived from butadiene structural units; generally, a lower butadiene content reduces the likelihood of fisheyes. Furthermore, excessively high molecular weights can also lead to gelation and thus fisheye formation. However, excessively low butadiene content or molecular weight results in reduced elongation.

[0008] The present invention was made in view of the above circumstances and aims to provide particles comprising a block copolymer composition that, when formed into a film, exhibits low fisheye formation and excellent tensile elongation.

[0009] Solution for solving the problem

[0010] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that by using a specific linear block copolymer containing a specified amount or more, and with the molecular weight and peak area measured based on GPC meeting specific conditions, the above-mentioned problems can be solved, thus completing the present invention.

[0011] The following invention is provided.

[0012] [1] A particle comprising a block copolymer composition, wherein,

[0013] The block copolymer composition comprises more than 95% by mass of a linear block copolymer mainly composed of vinyl aromatic monomer units and conjugated diene monomer units.

[0014] When the total amount of the vinyl aromatic monomer units and the conjugated diene monomer units in the block copolymer composition is 100% by mass, the content of the conjugated diene monomer units is 12-27% by mass.

[0015] In determining the converted molecular weight of polystyrene using gel permeation chromatography for the block copolymer composition, when the peak with the highest molecular weight among the peaks whose area ratio relative to the total peak area is 20% or more is taken as the main peak...

[0016] The peak molecular weight of the main peak is 150,000 to 300,000.

[0017] The total area of ​​the peak portion contained in the molecular weight range of 1.8 to 2.2 times the peak molecular weight of the main peak is less than 5% of the area of ​​the main peak.

[0018] [2] The particles according to [1], wherein the block copolymer composition comprises two or more of the linear block copolymers.

[0019] [3] A method for manufacturing particles as described in [1] or [2], comprising a polymerization step and a granulation step, wherein in the polymerization step, a monomer raw material comprising a vinyl aromatic monomer and a conjugated diene monomer is polymerized to obtain a polymerization solution comprising the linear block copolymer, wherein in the granulation step, the polymerization solution is granulated by devolatilization extrusion, wherein in the granulation step, when the resin temperature at the extruder outlet is T (°C), T satisfies formula (1).

[0020] (1) T≦-0.0129×B 2 -0.35×B+257

[0021] (B: The content (mass%) of the conjugated diene monomer units when the total amount of the vinyl aromatic monomer units and the conjugated diene monomer units in the block copolymer composition is 100% by mass)

[0022] [4] A film, which is a molded article of a raw material comprising the particles described in [1] or [2]. Detailed Implementation

[0023] The embodiments of the present invention will now be described. The various features shown in the embodiments described below can be combined with each other. Furthermore, each feature can independently constitute an invention. In the embodiments described below, elements not specified in the claims are arbitrary elements and can therefore be omitted. Any number of zeros (e.g., one or two) can be appended to the end of the numerical values ​​disclosed in the following description. For example, one or two zeros can be appended after "1.4" to make it "1.40" or "1.400".

[0024] 1. Particles

[0025] The particles according to one embodiment of the present invention are particles comprising a block copolymer composition. These particles can be used as raw materials (or a portion thereof) for films or sheets such as heat-shrinkable films, and for various other molded articles.

[0026] <Block Copolymer Compositions>

[0027] The block copolymer composition comprises at least 95% by mass of a linear block copolymer A, primarily composed of vinyl aromatic monomer units and conjugated diene monomer units, preferably 98-100% by mass, more preferably (substantially) 100% by mass. The content of the linear block copolymer A can specifically be, for example, 95, 96, 97, 98, 99, or 100% by mass, or a range between any two values ​​exemplified herein. Furthermore, the block copolymer composition comprises at least 95% by mass of linear block copolymer A, preferably 98-100% by mass, more preferably (substantially) 100% by mass, relative to 100% of the total polymers contained in the composition.

[0028] When the total number of monomer units (structural units) contained in the linear block copolymer A is 100% by mass, for example, when the total number of vinyl aromatic monomer units and conjugated diene monomer units is more than 98% by mass, it is preferably (substantially) 100% by mass.

[0029] Linear block copolymer A is a copolymer with a block structure, specifically a polymer where the block structure is formed in a linear chain. Block copolymers containing vinyl aromatic monomer units and conjugated diene monomer units can be obtained, for example, through living anionic polymerization in an organic solvent using organolithium compounds as polymerization initiators. In living anionic polymerization, since almost all of the vinyl aromatic monomers and conjugated diene monomers supplied for the polymerization reaction can be converted into polymers, block copolymers with arbitrary primary structures can be obtained by changing their amounts or order of addition.

[0030] The linear block copolymer A has two or more blocks selected from the group consisting of vinyl aromatic blocks (S), conjugated diene blocks (B), and copolymer blocks (S / B).

[0031] Linear block copolymer A, for example, has the following block structure.

[0032] (S)-(S / B)-(S / B)

[0033] (S) - (S / B)

[0034] (S)-(S / B)-(S)

[0035] (S)-(S / B)-(B)-(S)

[0036] (S)-(B)-(S)

[0037] When the total mass of the monomer units contained in the vinyl aromatic block (S) is set to 100% by mass, it contains more than 98% by mass of vinyl aromatic monomer units, more preferably more than 99% by mass, and most preferably 100% by mass. The vinyl aromatic block (S) can be essentially composed of only vinyl aromatic monomer units.

[0038] When the total mass of the monomer units contained in the block is set to 100% by mass, the conjugated diene block (B) contains more than 98% by mass of conjugated diene monomer units, more preferably more than 99% by mass, and most preferably 100% by mass. The conjugated diene block (B) can be essentially composed of only conjugated diene monomer units.

[0039] A copolymer block (S / B) is a block comprising vinyl aromatic monomer units and conjugated diene monomer units. When the total mass of the monomer units contained in the copolymer block is set to 100% by mass, it contains 2-98% by mass of conjugated diene monomer units, preferably 5-80% by mass, more preferably 7-60% by mass. The copolymer block (S / B) can be a tapered type, where the composition of the vinyl aromatic monomer units and conjugated diene monomer units varies continuously, or a random type, where the composition of the vinyl aromatic monomer units and conjugated diene monomer units is substantially constant.

[0040] Vinyl aromatic monomer units are units derived from vinyl aromatic monomers used in the polymerization of linear block copolymer A. Vinyl aromatic monomers are monomers with vinyl groups bonded to their aromatic rings. Examples of vinyl aromatic monomers include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene, etc. Styrene is preferred among the vinyl aromatic monomers. These monomers can be used alone or in combination of two or more.

[0041] The conjugated diene monomer unit is derived from the unit of the conjugated diene monomer used to polymerize linear block copolymer A. The conjugated diene monomer is a monomer having a conjugated chemical structure represented by C=C=C. Examples of conjugated diene monomers include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. 1,3-butadiene is preferred. These monomers can be used alone or in combination of two or more.

[0042] When the total mass of the monomer units contained in the linear block copolymer A is set to 100% by mass, the content of conjugated diene monomer units is preferably 6 to 45% by mass. When this range is met, it is easy to achieve both good tensile elongation and fewer fisheyes when molded into a film. Specifically, the content of these conjugated diene monomer units can be, for example, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, or 45% by mass, or a range between any two values ​​exemplified here.

[0043] The linear block copolymer A may contain monomer units (other monomer units) derived from monomers other than vinyl aromatic monomers and conjugated diene monomers that can copolymerize with them. When the total mass of the monomer units contained in the linear block copolymer A is set to 100% by mass, the content of other monomer units is, for example, 0 to 2% by mass, preferably 0% by mass.

[0044] When the total amount of vinyl aromatic monomer units and conjugated diene monomer units in the block copolymer composition is 100% by mass, the content of conjugated diene monomer units is 12-27% by mass, preferably 15-25% by mass. In the block copolymer composition, vinyl aromatic monomer units and conjugated diene monomer units exist as structural units constituting block copolymers such as linear block copolymer A. When the block copolymer composition contains two or more block copolymers, the content of this unit is calculated based on the total amount of each monomer unit in these block copolymers. When this range is met, fewer fisheyes are generated when molding into a film, and the tensile elongation is excellent. In particular, by keeping the content of conjugated diene monomer units below the upper limit, it is possible to suppress the formation of gel-like foreign matter from the structural units derived from conjugated diene monomers due to thermal crosslinking. The specific content of the conjugated diene monomer unit can be, for example, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27% by mass, or a range between any two values ​​exemplified here.

[0045] When the total number of monomer units contained in each polymer of the block copolymer composition is 100% by mass, the content of conjugated diene monomers is preferably 12-27% by mass, more preferably 15-25% by mass. Specifically, this content of conjugated diene monomer units can be, for example, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, or 27% by mass, or a range between any two values ​​exemplified herein.

[0046] In addition, the content of conjugated diene monomer units can be calculated not only from the amount of vinyl aromatic monomer units and conjugated diene monomers added during the manufacture of block copolymers, but also using the well-known halogen addition method. As a general example of the halogen addition method, the sample is dissolved in a solvent capable of complete dissolution, an excess of iodine monochloride / acetic acid solution is added to allow for complete reaction, then potassium iodide solution is added, and titration is performed with sodium thiosulfate / ethanol solution. The content of conjugated diene monomer units is calculated based on the amount of double bonds obtained by the above method. Regarding the content of vinyl aromatic monomer units, the content is calculated by subtracting the content of conjugated diene monomer units from the total sample content.

[0047] The block copolymer composition may also contain two or more linear block copolymers A, which differ from each other in the composition or molecular weight of their monomer units. Furthermore, it may also contain polymers other than linear block copolymers A.

[0048] When determining the equivalent molecular weight of polystyrene in block copolymer compositions by gel permeation chromatography (GPC), the peak molecular weight of the highest peak among those with an area ratio of 20% or more relative to the total peak area is taken as the main peak. The peak molecular weight of the main peak is typically between 150,000 and 300,000, preferably between 180,000 and 250,000. Within this range, the elongation at break when molded into a film is excellent. Particularly with excessively high molecular weights, thermal crosslinking due to shear heating is easily induced, potentially leading to gelation with fewer crosslinking cycles. The peak molecular weight of the main peak can be, for example, 150,000, 155,000, 160,000, 165,000, 170,000, 175,000, 180,000, 185,000, 190,000, 195,000, 200,000, 205,000, 210,000, 215,000, 220,000, 225,000, 230,000, 235,000, 240,000, 245,000, 250,000, 255,000, 260,000, 265,000, 270,000, 275,000, 280,000, 285,000, 290,000, 295,000, or 300,000, or a range between any two values ​​listed here.

[0049] In one embodiment, the total area of ​​the peak portion contained within a molecular weight range of 1.8 to 2.2 times the peak molecular weight of the main peak can be less than 5% of the main peak area, preferably less than 4%, and more preferably less than 3%. Here, "the total area of ​​the peak portion contained within a molecular weight range of 1.8 to 2.2 times the peak molecular weight of the main peak" means that regardless of whether the peak apex is contained within this 1.8 to 2.2 molecular weight range, as long as a portion of the peak is contained within this range, the area caused by that portion of the peak is included in the total area. Furthermore, if the entire peak is contained within this range, its entire area should be included in the total area.

[0050] When this range is met, fewer fisheyes are generated when forming the film. Within the range of 1.8 to 2.2 times the peak molecular weight of the main peak, dimers of the component corresponding to the main peak are predominantly present. Furthermore, the area of ​​the component with the peak within the range of 1.8 to 2.2 times can be controlled, for example, by molding conditions such as the resin temperature during particle forming. The ratio of this area to the main peak area is specifically, for example, 0, 0.5, 1.0, 1.5, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.5, 4.9%, or a range between any two values ​​exemplified here.

[0051] There are no particular limitations on the manufacturing method of linear block copolymer A. For example, linear block copolymer A can be obtained by carrying out a living anionic polymerization reaction of monomer raw materials containing vinyl aromatic monomers and conjugated diene monomers in an organic solvent using an organolithium compound as a polymerization initiator.

[0052] Examples of organic solvents include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane, and isooctane; alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane; and aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene. Cyclohexane is a particularly preferred organic solvent.

[0053] Organolithium compounds are compounds in which one or more lithium atoms are bonded to other atoms. Examples of organolithium compounds include monofunctional organolithium compounds such as ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, and tert-butyllithium, as well as polyfunctional organolithium compounds such as hexamethylene dilithium, butadiene dilithium, and isoprene dilithium. A particularly preferred organolithium compound is n-butyllithium.

[0054] In living anionic polymerization, block copolymers with arbitrary primary structures can be obtained by changing the amount or method of adding monomer raw materials. For example, the molecular weight can be adjusted by the ratio of organolithium compounds to monomer raw materials, and the ratio of vinyl aromatic monomer units and conjugated diene monomer units in each block chain can be controlled by adding them in sequence or batches.

[0055] The block copolymer obtained in this manner is deactivated by adding a polymerization terminator such as water, alcohol, or carbon dioxide in an amount sufficient to deactivate the active ends. As a method for recovering the copolymer from the resulting block copolymer solution (polymerization solution), any method can be used, such as (A) precipitation using a lean solvent such as methanol; (B) precipitation using solvent evaporation using a heated roller (drum drying method); (C) concentration of the solution using a concentrator followed by solvent removal via a degassing extruder (devouring extrusion method); (D) dispersion of the solution in water, followed by heating with steam to remove the solvent and recover the copolymer (steam stripping method), etc. Devouring extrusion is particularly preferred.

[0056] According to one embodiment of the present invention, a block copolymer composition can be obtained by mixing at least one block copolymer obtained by the above-described manufacturing method with other additives added as needed.

[0057] Other additives include various stabilizers, lubricants, processing aids, anti-blocking agents, antistatic agents, anti-fogging agents, lightfastness enhancers, softeners, plasticizers, and pigments. These additives can be added to the block copolymer solution or blended and melt-mixed with recycled copolymers.

[0058] Examples of stabilizers include phenolic antioxidants such as 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and 2,6-di-tert-butyl-4-methylphenol; and phosphorus-based antioxidants such as trinonylphenyl phosphite. Examples of anti-blocking agents, antistatic agents, and lubricants include fatty acid amides, ethylene bis-stearamide, sorbitol monostearate, saturated fatty acid esters of aliphatic alcohols, and pentaerythritol fatty acid esters. These additives are preferably used in the range of 5% by mass or less relative to the block copolymer.

[0059] The block copolymer composition according to one embodiment of the present invention sometimes contains two or more block copolymers, and known methods can be used for mixing these block copolymers. For example, dry mixing can be performed using a Henschel mixer, ribbon mixer, super mixer, and V-type mixer, followed by further melting and granulation using an extruder. In one embodiment, melt mixing is preferred. Alternatively, a method can be used where the polymer solutions (polymerization solutions) are mixed together and then the solvent is removed.

[0060] <Methods for manufacturing granules>

[0061] The particles according to one embodiment of the present invention are granules comprising the above-described block copolymer composition, which are substances obtained by molding a polymer solution (polymerization solution) of the block copolymer composition or a linear block copolymer A, which is a component of the block copolymer composition, into granules.

[0062] The method of manufacturing the granules is not particularly limited as long as it does not impair the physical properties of the block copolymer composition constituting the granules, but it can be, for example, a method that includes a polymerization step and a granulation step. The method of manufacturing the granules may also include a mixing step.

[0063] In the polymerization process, monomer feedstocks containing vinyl aromatic monomers and conjugated diene monomers are polymerized to obtain a polymerization solution containing one or more linear block copolymers A. The polymerization of the monomer feedstocks can be carried out, for example, by the living anionic polymerization reaction described above. The polymerization solution is deactivated by adding a polymerization terminator.

[0064] In the mixing process, two or more polymerization solutions containing one or more linear block copolymers A are mixed to obtain a mixed solution. For example, mixing a polymerization solution containing one linear block copolymer A with a polymerization solution containing two linear block copolymers A can yield a new polymerization solution (mixed solution) containing three linear block copolymers A.

[0065] In the granulation process, the deactivated polymer solution (or mixed polymer solution) is granulated by devolatilization extrusion. In devolatilization extrusion, the polymer solution is concentrated using a concentrator and then the solvent is removed by a degassing extruder. During devolatilization extrusion, when the resin temperature at the extruder outlet is T (°C), granulation is carried out under the condition that T satisfies the following formula (1), which can suppress dimerization (e.g., the formation of dimers corresponding to the main peak caused by thermal crosslinking), thereby achieving a low fisheye level. The resin temperature at the extruder outlet can be adjusted by the screw speed of the extruder, the discharge rate, and the temperature of the polymer solution fed into the extruder.

[0066] (1) T≦-0.0129×B 2-0.35×B+257

[0067] (B: The content (by mass%) of the conjugated diene monomer unit when the total amount of the vinyl aromatic monomer unit and the conjugated diene monomer unit in the block copolymer composition is 100% by mass)

[0068] 2. Film

[0069] The film according to one embodiment of the present invention is a molded product of the above-described particles. This film is, for example, a heat-shrinkable film, and specifically a heat-shrinkable film containing the above-described block copolymer composition. The heat-shrinkable film can be obtained by using the above-described particles to stretch a sheet or film extruded by a known method (e.g., T-die method, tubular film method) uniaxially, biaxially, or multiaxially. Biaxial stretching using the T-die method is particularly preferred.

[0070] According to one embodiment of the present invention, the heat-shrinkable film can be made either by using a layer comprising the above-described block copolymer composition alone, or by laminating other resin layers onto at least one side of the film to form a heat-shrinkable multilayer film. To obtain a heat-shrinkable multilayer film, other resin layers can be laminated onto a stretched heat-shrinkable film; other resin layers can be laminated onto an unstretched film (hereinafter, for distinction, sometimes referred to as a "sheet") obtained by forming a resin composition, followed by stretching; and multilayer sheets laminated by multilayer extrusion molding of a resin composition and other resins can also be stretched. Styrene-based resins are preferred as the resins used for the other resin layers.

[0071] Examples of uniaxial stretching include methods such as stretching extruded sheets in a direction orthogonal to the extrusion direction (TD) using a tenter frame, and stretching extruded tubular films in the circumferential direction.

[0072] Examples of biaxial stretching include methods such as stretching an extruded sheet in the extrusion direction (MD) using a roller and then stretching it in the direction orthogonal to the extrusion direction (TD) using a tenter frame, and methods such as stretching an extruded tubular film simultaneously or separately in the extrusion direction and the circumferential direction.

[0073] The stretching temperature is preferably, for example, 60 to 120°C. Setting the temperature above 60°C makes the sheet less prone to breakage during stretching, and setting it below 120°C easily results in good shrinkage characteristics and thickness accuracy of the film. The stretch ratio is not particularly limited, but is preferably 1.5 to 8 times. Setting it above 1.5 times easily results in good heat shrinkage, and setting it below 8 times makes the sheet less prone to breakage during stretching. When these stretched films are used as heat-shrinkable labels or packaging materials, the heat shrinkage rate at 80°C is preferably 20% or more. If it is less than 20%, high temperatures are required for shrinkage, which can adversely affect the covered items and is therefore not preferred. The film thickness is preferably 10 to 300 μm.

[0074] The aforementioned heat-shrinkable film can be used as heat-shrinkable labels, heat-shrinkable bottle cap seals, etc. It can also be used as packaging film.

[0075]

Example

[0076] The present invention will be described in more detail below by way of examples. It should be noted that these are all exemplary and do not limit the scope of the present invention.

[0077] [Preparation of block copolymer compositions and particles]

[0078] Particles (P-1) to (P-9) were produced by the following operations.

[0079] <Particle (P-1)>

[0080] (Polymerization step 1-1) Preparation of block copolymer polymerization solution (S-1)

[0081] (1) 467 kg of cyclohexane was added to the reaction vessel.

[0082] (2) While stirring at an internal temperature of 30°C, add 1380 mL of n-butyllithium (10% cyclohexane solution), then add 8.0 kg of styrene, and heat to 80°C to polymerize it.

[0083] (3) After the styrene is completely consumed, while maintaining the internal temperature at 80°C, 110.0 kg of styrene and 10.0 kg of 1,3-butadiene are added at constant rates of 143.0 kg / h and 13.0 kg / h, respectively. After the addition is completed, the state is maintained for a sufficient period of time.

[0084] (4) After the styrene is completely consumed, adjust the internal temperature to 70°C, add 22.0 kg of 1,3-butadiene, and heat it to polymerize.

[0085] (5) After the 1,3-butadiene is completely consumed, the internal temperature is adjusted to 60℃, and 50.0 kg of styrene is added to polymerize it.

[0086] (6) After the styrene is completely consumed, 220g of water is added to deactivate it, thereby obtaining the block copolymer polymerization solution (S-1).

[0087] (Polymerization step 1-2) Preparation of block copolymer polymerization solution (S-2)

[0088] (1) 467 kg of cyclohexane was added to the reaction vessel.

[0089] (2) Add 2480 mL of n-butyllithium (10% cyclohexane solution) while stirring at an internal temperature of 30°C, then add 40.0 kg of styrene and heat to 80°C to polymerize it.

[0090] (3) After the styrene is completely consumed, while maintaining the internal temperature at 80°C, 36.0 kg of styrene and 8.0 kg of 1,3-butadiene are added at constant rates of 120.0 kg / h and 26.7 kg / h, respectively. After the addition is completed, the state is maintained for a sufficient period of time.

[0091] (4) After the styrene is completely consumed, adjust the internal temperature to 50°C, add 66.0 kg of 1,3-butadiene, and heat it to polymerize.

[0092] (5) After the 1,3-butadiene is completely consumed, the internal temperature is adjusted to 60℃, and 50.0 kg of styrene is added to polymerize it.

[0093] (6) After the styrene is completely consumed, 390g of water is added to deactivate it, thereby obtaining the block copolymer polymerization solution (S-2).

[0094] (Mixing process 1)

[0095] Polymer solutions S-1 and S-2 were mixed at a weight ratio of (S-1):(S-2) = 66.7:33.3 to obtain mixed solution 1.

[0096] (Granulation process 1)

[0097] Mixture solution 1 was formed using a devolatilization extruder to obtain granules P-1. The resin temperature at the extruder outlet was 238°C. The block copolymer composition constituting granules P-1 contained approximately 100% by mass of linear block copolymers. In addition to linear block copolymers, the block copolymer composition may also contain lithium salts derived from organolithium compounds, but these are present in extremely small amounts relative to the mass of the linear block copolymers; therefore, the content of linear block copolymers can be considered to be approximately 100% by mass. Other examples are similar.

[0098] <Particles (P-2)>

[0099] (Polymerization step 2-1) Preparation of block copolymer polymerization solution (S-2)

[0100] By performing the same operations as (polymerization steps 1-2), a block copolymer polymerization solution (S-2) was obtained.

[0101] (Polymerization step 2-2) Preparation of block copolymer polymerization solution (S-3)

[0102] (1) 467 kg of cyclohexane was added to the reaction vessel.

[0103] (2) While stirring at an internal temperature of 30°C, add 1000 mL of n-butyllithium (10% cyclohexane solution), then add 40.0 kg of styrene, and heat to 80°C to polymerize it.

[0104] (3) After the styrene is completely consumed, while maintaining the internal temperature at 80°C, 102.0 kg of styrene and 18.0 kg of 1,3-butadiene are added simultaneously at constant addition rates of 153.0 kg / h and 24.0 kg / h, respectively. After the addition is completed, the state is maintained for a sufficient period of time.

[0105] (4) After the styrene is completely consumed, adjust the internal temperature to 60°C, add 40.0 kg of styrene, and heat it to polymerize.

[0106] (5) After the styrene is completely consumed, 150g of water is added to deactivate it, thereby obtaining the block copolymer polymerization solution (S-3).

[0107] (Mixed Process 2)

[0108] Polymer solutions S-2 and S-3 were mixed at a weight ratio of (S-2):(S-3) = 33.3:66.7 to obtain mixed solution 2.

[0109] (Pelletizing process 2)

[0110] Mixture solution 2 was molded using a devouring extruder to obtain granules P-2. The resin temperature at the extruder outlet was 242°C. The block copolymer composition constituting granules P-2 contained approximately 100% by mass of linear block copolymers.

[0111] <Particles (P-3)>

[0112] (Polymerization step 3-1) Preparation of block copolymer polymerization solution (S-4)

[0113] (1) 467 kg of cyclohexane was added to the reaction vessel.

[0114] (2) While stirring at an internal temperature of 30°C, add 1450 mL of n-butyllithium (10% cyclohexane solution), then add 122.0 kg of styrene, and heat to 80°C to polymerize it.

[0115] (3) After the styrene is completely consumed, the internal temperature is adjusted to 50℃ and 46.0 kg of styrene and 32.0 kg of 1,3-butadiene are added at one time, and the temperature is raised to polymerize it.

[0116] (4) After styrene and 1,3-butadiene are completely consumed, 230g of water is added to deactivate them, thereby obtaining a block copolymer polymerization solution (S-4).

[0117] (Polymerization step 3-2) Preparation of block copolymer polymerization solution (S-5)

[0118] (1) 467 kg of cyclohexane was added to the reaction vessel.

[0119] (2) While stirring at an internal temperature of 30°C, add 1180 mL of n-butyllithium (10% cyclohexane solution), then add 32.0 kg of styrene, and heat to 80°C to polymerize it.

[0120] (3) After the styrene is completely consumed, the internal temperature is adjusted to 50°C, and 67.0 kg of styrene and 9.0 kg of 1,3-butadiene are added at one time, and the temperature is raised to polymerize it.

[0121] (4) After the styrene and 1,3-butadiene are completely consumed, the internal temperature is adjusted to 50°C, and 67.0 kg of styrene and 25.0 kg of 1,3-butadiene are added at one time, and the temperature is raised to polymerize them.

[0122] (5) After styrene and 1,3-butadiene are completely consumed, 190g of water is added to deactivate them, thereby obtaining a block copolymer polymerization solution (S-5).

[0123] (Mixing process 3)

[0124] Polymer solutions S-4 and S-5 were mixed at a weight ratio of (S-4):(S-5) = 30:70 to obtain mixed solution 3.

[0125] (Pelletizing process 3)

[0126] Mixture solution 3 was molded using a devouring extruder to obtain granules P-3. The resin temperature at the extruder outlet was 238°C. The block copolymer composition constituting granules P-3 contained approximately 100% by mass of linear block copolymers.

[0127] <Particles (P-4)>

[0128] (Polymerization step 4-1) Preparation of block copolymer polymerization solution (S-4)

[0129] By performing the same operation as (polymerization step 3-1), a block copolymer polymerization solution (S-4) was obtained.

[0130] (Polymerization step 4-2) Preparation of block copolymer polymerization solution (S-6)

[0131] (1) 467 kg of cyclohexane was added to the reaction vessel.

[0132] (2) While stirring at an internal temperature of 30°C, add 3720 mL of n-butyllithium (10% cyclohexane solution), then add 50.0 kg of styrene, and heat to 80°C to polymerize it.

[0133] (3) After the styrene is completely consumed, the internal temperature is adjusted to 35°C, and 60.0 kg of styrene and 90.0 kg of 1,3-butadiene are added at one time, and the temperature is raised to polymerize it.

[0134] (4) After styrene and 1,3-butadiene are completely consumed, 620g of water is added to deactivate them, thereby obtaining a block copolymer polymerization solution (S-6).

[0135] (Mixing process 4)

[0136] Polymerization solutions S-4 and S-6 were mixed at a weight ratio of (S-4):(S-6) = 66.7:33.3 to obtain mixed solution 4.

[0137] (Granulation process 4)

[0138] Mixture solution 4 was molded using a devolatilization extruder to obtain granules P-4. The resin temperature at the extruder outlet was 234°C. The block copolymer composition constituting granules P-4 contained approximately 100% by mass of linear block copolymers.

[0139] <Particles (P-5)>

[0140] (Polymerization step 5-1) Preparation of block copolymer polymerization solution (S-1)

[0141] By performing the same operation as (polymerization step 1-1), a block copolymer polymerization solution (S-1) was obtained.

[0142] (Polymerization step 5-2) Preparation of block copolymer polymerization solution (S-2)

[0143] By performing the same operations as (polymerization steps 1-2), a block copolymer polymerization solution (S-2) was obtained.

[0144] (Mixing process 5)

[0145] Polymerization solutions S-1 and S-2 were mixed at a weight ratio of (S-1):(S-2) = 66.7:33.3 to obtain mixed solution 5.

[0146] (Pelletizing process 5)

[0147] Mixture solution 5 was shaped using a devolatilization extruder to obtain granules P-5. The resin temperature at the extruder outlet was 247°C. The block copolymer composition constituting granules P-5 contained approximately 100% by mass of linear block copolymers.

[0148] <Particles (P-6)>

[0149] (Polymerization step 6-1) Preparation of block copolymer polymerization solution (S-4)

[0150] By performing the same operation as (polymerization step 3-1), a block copolymer polymerization solution (S-4) was obtained.

[0151] (Polymerization step 6-2) Preparation of block copolymer polymerization solution (S-5)

[0152] By performing the same operation as (polymerization step 3-2), a block copolymer polymerization solution (S-5) was obtained.

[0153] (Mixing process 6)

[0154] Polymer solutions S-4 and S-5 were mixed at a weight ratio of (S-4):(S-5) = 30:70 to obtain mixed solution 6.

[0155] (Pelletizing process 6)

[0156] Mixture solution 6 was molded using a devolatilization extruder to obtain granules P-6. The resin temperature at the extruder outlet was 250°C. The block copolymer composition constituting granules P-6 contained approximately 100% by mass of linear block copolymers.

[0157] <Particles (P-7)>

[0158] (Polymerization step 7-1) Preparation of block copolymer polymerization solution (S-7)

[0159] (1) 467 kg of cyclohexane was added to the reaction vessel.

[0160] (2) While stirring at an internal temperature of 30°C, add 1560 mL of n-butyllithium (10% cyclohexane solution), then add 8.0 kg of styrene, and heat to 80°C to polymerize it.

[0161] (3) After the styrene is completely consumed, while maintaining the internal temperature at 80°C, 98.0 kg of styrene and 10.0 kg of 1,3-butadiene are added at constant rates of 147.0 kg / h and 15.0 kg / h, respectively. After the addition is completed, the state is maintained for a sufficient period of time.

[0162] (4) After the styrene is completely consumed, adjust the internal temperature to 60°C, add 50.0 kg of 1,3-butadiene, and heat it to polymerize.

[0163] (5) After the 1,3-butadiene is completely consumed, the internal temperature is adjusted to 60℃, and 34.0 kg of styrene is added to polymerize it.

[0164] (6) After the styrene is completely consumed, 250g of water is added to deactivate it, thereby obtaining the block copolymer polymerization solution (S-7).

[0165] (Pelletizing process 7)

[0166] The polymerization solution S-7 was molded using a devouring extruder to obtain granules P-7. The resin temperature at the extruder outlet was 235°C. The block copolymer composition constituting granules P-7 contained approximately 100% by mass of linear block copolymers.

[0167] <Particles (P-8)>

[0168] (Polymerization step 8-1) Preparation of block copolymer polymerization solution (S-3)

[0169] By performing the same operation as (polymerization step 2-2), a block copolymer polymerization solution (S-3) was obtained.

[0170] (Pelletizing process 8)

[0171] The polymerization solution S-3 was molded using a devouring extruder to obtain granules P-8. The resin temperature at the extruder outlet was 245°C. The block copolymer composition constituting granules P-8 contained approximately 100% by mass of linear block copolymers.

[0172] <Particles (P-9)>

[0173] (Polymerization step 9-1) Preparation of block copolymer polymerization solution (S-2)

[0174] By performing the same operations as (polymerization steps 1-2), a block copolymer polymerization solution (S-2) was obtained.

[0175] (Polymerization step 9-2) Preparation of block copolymer polymerization solution (S-9)

[0176] (1) 467 kg of cyclohexane was added to the reaction vessel.

[0177] (2) While stirring at an internal temperature of 30°C, add 1800 mL of n-butyllithium (10% cyclohexane solution), then add 8.0 kg of styrene, and heat to 80°C to polymerize it.

[0178] (3) After the styrene is completely consumed, while maintaining the internal temperature at 80°C, 110.0 kg of styrene and 10.0 kg of 1,3-butadiene are added at constant rates of 143.0 kg / h and 13.0 kg / h, respectively. After the addition is completed, the state is maintained for a sufficient period of time.

[0179] (4) After the styrene is completely consumed, adjust the internal temperature to 70°C, add 22.0 kg of 1,3-butadiene, and heat it to polymerize.

[0180] (5) After the 1,3-butadiene is completely consumed, the internal temperature is adjusted to 60℃, and 50.0 kg of styrene is added to polymerize it.

[0181] (6) After the styrene is completely consumed, 290g of water is added to deactivate it, thereby obtaining the block copolymer polymerization solution (S-9).

[0182] (Mixing process 9)

[0183] Polymerization solutions S-2 and S-9 were mixed at a weight ratio of (S-2):(S-9) = 33.3:66.7 to obtain mixed solution 9.

[0184] (Pelletizing process 9)

[0185] Mixture solution 9 was molded using a devouring extruder to obtain granules P-9. The resin temperature at the extruder outlet was 237°C. The block copolymer composition constituting granules P-9 contained approximately 100% by mass of linear block copolymers.

[0186] [Single unit ratio]

[0187] The contents of vinyl aromatic monomer units (styrene monomer units) and conjugated diene monomer units (1,3-butadiene monomer units) in the block copolymer composition were determined and calculated by halogen addition method.

[0188] (A1) Dissolve 0.2g of the sample in a solvent (such as carbon tetrachloride) that can completely dissolve it, then add 15ml of Wijs reagent (0.1mol / L iodine chloride-acetic acid solution) to allow it to react fully. Then add 20ml of 4% potassium iodide solution and titrate with 0.1mol / L sodium thiosulfate / ethanol solution to calculate the amount of double bond.

[0189] (A2) Based on the amount of double bonds obtained by method (A1), calculate the content of butadiene monomer units (rubber component). The styrene content is calculated by subtracting the butadiene content from the total sample content.

[0190] When the total amount of vinyl aromatic monomer units (styrene monomer units) and conjugated diene monomer units (1,3-butadiene monomer units) in the block copolymer composition is 100% by mass, the content of conjugated diene monomer units is shown in Table 2.

[0191] [GPC Measurement]

[0192] The GPC of the block copolymer composition was determined using the following GPC measuring apparatus and conditions. Based on the results, the peak molecular weight and peak area of ​​each component were calculated. The results are shown in Table 2.

[0193] Device Name: HLC-8220GPC (Manufactured by Tosoh Corporation)

[0194] Chromatographic column: Four Shodex GPCKF-404 (manufactured by Showa Denko Corporation) columns connected in series.

[0195] Temperature: 40℃

[0196] Detection: Differential refractive index

[0197] Solvent: Tetrahydrofuran

[0198] Concentration: 2% by mass

[0199] Standard curve: made using standard polystyrene (manufactured by VARIAN).

[0200] [Determination of Molding Conditions]

[0201] When the resin temperature at the extruder outlet is T (°C), if T satisfies the following formula (1), it is marked as "○"; otherwise, it is marked as "×".

[0202] (1) T≦-0.0129×B 2 -0.35×B+257

[0203] (B: The content (mass%) of the conjugated diene monomer units when the total of the vinyl aromatic monomer units and the conjugated diene monomer units in the block copolymer composition is 100% by mass)

[0204] [Examples 1-4 and Comparative Examples 1-5]

[0205] For each particle, the stretch elongation and the fisheye level during film fabrication were evaluated.

[0206] <Tension elongation>

[0207] According to JIS K 7161, for dumbbell-shaped specimens produced by particle injection molding, the nominal strain at tensile fracture was measured using Shimadzu Autograph AG-Xplus at a tensile speed of 50 mm / min, and this strain was used as the value of tensile elongation. The tensile elongation was then evaluated according to the following criteria. The evaluation results for each example and comparative example are shown in Table 2.

[0208] ○:More than 10%

[0209] ×: Less than 10%

[0210] <Fisheye level>

[0211] Unstretched films were produced using a sheet extruder equipped with a T-die at 220°C, and their dimensions (3.3m) were measured using an image recognition device. 2 The number of foreign objects larger than 0.2 mm was measured and evaluated according to the following criteria. The evaluation results for each embodiment and comparative example are shown in Table 2.

[0212] ○: Less than 150

[0213] ×: More than 150

[0214] In addition, the “total area of ​​the peak portion within the specified range” in Table 2 refers to “the total area of ​​the peak portion contained within a molecular weight range of 1.8 to 2.2 times the peak molecular weight of the main peak”.

[0215] Table 1

[0216]

[0217] Table 2

[0218]

Claims

1. A particle comprising a block copolymer composition, wherein, The block copolymer composition comprises more than 95% by mass of a linear block copolymer mainly composed of vinyl aromatic monomer units and conjugated diene monomer units. When the total amount of the vinyl aromatic monomer units and the conjugated diene monomer units in the block copolymer composition is 100% by mass, the content of the conjugated diene monomer units is 12-27% by mass. In determining the converted molecular weight of polystyrene using gel permeation chromatography for the block copolymer composition, when the peak with the highest molecular weight among the peaks whose area ratio relative to the total peak area is 20% or more is taken as the main peak... The peak molecular weight of the main peak is 150,000 to 300,000. The total area of ​​the peak portion contained in the molecular weight range of 1.8 to 2.2 times the peak molecular weight of the main peak is less than 5% of the area of ​​the main peak.

2. The particles according to claim 1, wherein, The block copolymer composition comprises two or more of the linear block copolymers.

3. A method for manufacturing the particles according to claim 1 or 2, wherein, Including polymerization and granulation processes, In the polymerization process, monomer feedstocks comprising vinyl aromatic monomers and conjugated diene monomers are polymerized to obtain a polymerization solution containing the linear block copolymer. In the granulation process, the polymerization solution is granulated by devolatilization extrusion. In the granulation process, when the resin temperature at the extruder outlet is T (°C), T satisfies equation (1). (1)T≦-0.0129×B 2 -0.35×B+257 (B: The content (mass%) of the conjugated diene monomer unit when the total of the vinyl aromatic monomer unit and the conjugated diene monomer unit in the block copolymer composition is 100% by mass).

4. A film, which is a molded article comprising the particles of claim 1 or 2.

Images