WO2020261888A1 - Procédé de production de granulés - Google Patents

Procédé de production de granulés Download PDF

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Publication number
WO2020261888A1
WO2020261888A1 PCT/JP2020/021678 JP2020021678W WO2020261888A1 WO 2020261888 A1 WO2020261888 A1 WO 2020261888A1 JP 2020021678 W JP2020021678 W JP 2020021678W WO 2020261888 A1 WO2020261888 A1 WO 2020261888A1
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WIPO (PCT)
Prior art keywords
strand
water
less
cooling
strands
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PCT/JP2020/021678
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English (en)
Japanese (ja)
Inventor
前田　健作
剣太郎 鴨垣
鮎澤　佳孝
Original Assignee
東洋紡株式会社
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Publication of WO2020261888A1 publication Critical patent/WO2020261888A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B9/00—Making granules
    • B29B9/02—Making granules by dividing preformed material
    • B29B9/06—Making granules by dividing preformed material in the form of filamentary material, e.g. combined with extrusion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/001—Combinations of extrusion moulding with other shaping operations
    • B29C48/0022—Combinations of extrusion moulding with other shaping operations combined with cutting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/05—Filamentary, e.g. strands
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
    • B29C48/919—Thermal treatment of the stream of extruded material, e.g. cooling using a bath, e.g. extruding into an open bath to coagulate or cool the material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/92—Measuring, controlling or regulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2948/00—Indexing scheme relating to extrusion moulding
    • B29C2948/92—Measuring, controlling or regulating
    • B29C2948/92504—Controlled parameter
    • B29C2948/92704—Temperature

Definitions

  • the present invention relates to a method for producing pellets composed of a composition containing a thermoplastic resin.
  • compositions containing thermoplastics include injection molding materials such as home appliances and various automobile parts, clothing such as fiber yarns and knitted fabrics, industrial or leisure filament materials such as tire cords, fishing nets and fishing lines, and food packaging. It is used as a film for, various container sheets, bottle materials, etc. Depending on the composition, such a composition has chemical and mechanical properties such as high strength, abrasion resistance, fatigue resistance, good dyeability, and gas barrier property.
  • Pellets made of a composition containing a thermoplastic resin can be produced, for example, by extruding a strand made of a melted composition from a die with an extruder, cooling the strand, and cutting the cooled strand. Yes (see, for example, Patent Document 1).
  • Patent Document 1 describes that the length of the strands in water is set within a predetermined range in order to sufficiently reduce the water content in the pellets.
  • An object of the present invention is to provide a method for producing pellets, which can reduce the frequency of occurrence of hollow pellets while keeping the water content immediately after pelletizing below a certain level.
  • the present inventor has found that the hollow pellets are due to the non-uniform solidification state of the strands in water cooling, and by improving this, the present invention is completed. It came to.
  • the present invention includes the configuration of item 1 below.
  • Item 1 A process of extruding a strand made of a composition containing a thermoplastic resin from a die discharge port, and The process of cooling while taking over the strands and Including the step of cutting the cooled strand to obtain pellets.
  • the step of cooling the strand the strand is picked up at 20 cm / sec to 140 cm / sec.
  • the step of cooling the strands includes a step of drawing the strands into water in a water tank and cooling them with water.
  • the length L of the strands immersed in the water in the aquarium satisfies Equation 1.
  • the formula 1 is L 1 ⁇ L ⁇ L 2
  • D p is the diameter of the pellet, represented in mm.
  • T D is the temperature of the composition in the discharge port, expressed in ° C.
  • TC2 is the falling crystallization temperature of the composition, expressed in ° C.
  • TW is the temperature of the water in the aquarium, expressed in ° C.
  • v is the rate at which the strands are picked up, expressed in cm / sec.
  • K 2 is 0.37, Pellet manufacturing method.
  • the strand since the strand is drawn into the water in the water tank and cooled by water, the strand can be cooled isotropically in the radial direction (specifically, the radial direction of the strand).
  • the frequency of occurrence of hollow pellets can be reduced.
  • the mechanism is as follows. ------ When the water immersion length L is L 1 or more, not only the solidification of the surface layer portion of the strand is started during water cooling, but also the solidification of the inside of the strand (that is, the portion closer to the axis than the surface layer portion) is started. be able to. This is because L 1 indicates the length of the strand in water (underwater length) to be immersed in the water in the water tank in order to initiate solidification inside the strand during water cooling. This will be described in detail later.
  • the difference between the solidification rate of the surface layer and the solidification rate of the inside is compared with the case where the solidification of the inside is started during air cooling. Can be shortened. This is because water cooling has a higher cooling effect than air cooling, so that the inside can be effectively cooled.
  • By being able to reduce the difference between the solidification rate of the surface layer and the solidification rate of the inside it is possible to prevent the inside from solidifying and shrinking with a greater delay than the surface layer, thus preventing the formation of cavities in the strands. Can be prevented.
  • L 1 indicates the underwater length of the strand to be immersed in the water in the aquarium in order to initiate solidification inside the strand during water cooling.
  • the reason is as follows. ------ Regarding the equation for deriving L 1 , since TC 2 is the falling crystallization temperature, TC 2 can be regarded as the temperature at which solidification of the strand starts, so that T D -TC 2 is the temperature at the discharge port and Indicates the distance from the temperature at which solidification begins. Meanwhile, the larger the opening between T D and T W, because the cooling rate of the strand is high, T D -T W can Mitateru the cooling rate of the strand.
  • (T D -T C2) / (T D -T W) indicates an index of a time required for the strand begins to solidify. This is because the T D -T C2 as distance (distance on the temperature), by dividing by T D -T W as cooling rate, the strands can be obtained an indication of the time required to initiate solidification Because.
  • the strand as an indicator of the time required to initiate the solidification (T D -T C2) / ( T D -T W), by applying a v, water in the water tank to initiate solidification of the strand An index indicating the underwater length of the strand to be immersed in can be obtained.
  • v is the speed at which the strands are picked up, that is, the speed at which the strands move in the aquarium.
  • ⁇ (T D -T C2) / (T D -T W) ⁇ ⁇ v indicates a water length of the strand to be immersed in the water in the water tank to initiate the solidification of "surface layer portion" of the strand It's just an indicator, not even an indicator of the underwater length of a strand that should be submerged in the water in the aquarium to initiate solidification of the "inside" of the strand (ie, the part closer to the axis than the surface). I can not say.
  • pellets having a water content of less than a certain level immediately after pelletizing for example, pellets having a water content of less than 0.10% by mass can be obtained.
  • L 2 indicates the length of the strand in water at which the water absorption rate in water cooling is less than 0.10% by mass (this will be described in detail later).
  • the water absorption rate in water cooling controls the water content immediately after pelletizing.
  • the water absorption rate is used in the sense of (mass of water absorbed by the strand during water cooling) / (net mass of the strand). The mass of water absorbed by the strands during water cooling is called the "water absorption mass".
  • the net mass of the strands is referred to as the "net mass". Since the moisture content immediately after pelletizing is below a certain level, it is possible to omit the operation of drying the pellets using a drying facility (for example, the operation of applying drying air to the pellets) and shorten the time required for the operation. Is. Therefore, the cost for drying the pellets can be suppressed.
  • a drying facility for example, the operation of applying drying air to the pellets
  • L 2 indicates the length of the strand in water at which the water absorption rate in water cooling is less than 0.10% by mass.
  • the reason is as follows. ------ The water absorption mass constituting the water absorption rate (water absorption mass / net mass) can be roughly expressed by the water absorption rate ⁇ the immersion time. This is because the faster the water absorption rate, the larger the water absorption mass, and the longer the immersion time, the larger the water absorption mass. Since the water absorption rate increases as the surface area of the strand increases, the water absorption rate can be roughly expressed by the underwater length of k ⁇ ⁇ ⁇ D p ⁇ strand using the formula of the side area of the cylinder.
  • k is a coefficient and ⁇ is pi.
  • the water absorption mass can be roughly expressed by the following formula.
  • Water absorption mass k ⁇ ⁇ ⁇ D p ⁇ Strand length in water ⁇ Immersion time
  • D p / 2) It can be roughly expressed by 2 ⁇ the length of the strand in water ⁇ d.
  • d is the density of the strands. Therefore, the water absorption rate (water absorption mass / net mass) can be roughly expressed by the following formula.
  • k ′′ is a coefficient.
  • lowering the crystallization temperature T C2 in accordance with JIS K 7121-1987, is measured by differential scanning calorimetry. Specifically, a test piece having a thickness of 0.5 mm or less is cut out from the pellet, and the test piece for 5 mg is heated to 300 ° C. at a heating rate of 20 ° C./min under a nitrogen stream, and then under a nitrogen stream. After holding at that temperature (300 ° C.) for 5 minutes, the temperature is lowered to 100 ° C. at a rate of 10 ° C./min under a nitrogen stream. In the DSC curve obtained by this, a peak top temperature of the maximum exothermic peak at the time of cooling, read as drop crystallization temperature T C2. An empty container is used as a reference substance. The falling crystallization temperature TC2 is the so-called crystallization peak temperature.
  • the present invention further includes the configurations of the following item 2 and subsequent items.
  • Item 2 Item 2.
  • the content of the reinforcing material is 30% by mass or less, hollow pellets are likely to be generated in the conventional production method, but according to the present invention, the frequency of occurrence of hollow pellets can be effectively reduced.
  • Item 3 Item 2.
  • the composition does not contain a reinforcing material, hollow pellets are likely to be generated in the conventional production method, but according to the present invention, the frequency of occurrence of hollow pellets can be effectively reduced.
  • the temperature T W of the water in the water tank is 3 °C ⁇ 80 °C, method for producing pellets according to any one of claim 1-3. Since the cooling rate of the water cooling process is slower than that of less than 3 ° C when the temperature is 3 ° C or higher, the difference between the solidification rate of the surface layer in water cooling and the internal solidification rate in water cooling should be reduced. Can be done. As a result, it is possible to prevent the inside from solidifying and shrinking with a greater delay than the surface layer portion during water cooling, and thus it is possible to prevent the formation of cavities in the strands during water cooling. When the temperature is 80 ° C. or lower, the strands can be effectively cooled.
  • Temperature T W of the water in the water tank is higher than the glass transition temperature of the composition, manufacturing method of the pellets according to any one of claim 1-4.
  • the cooling rate is slow, and solidification rate of the surface layer portion in a water-cooled, the difference between the internal solidification rate in a water-cooled small can do.
  • the glass transition temperature T g is measured with a differential scanning calorimeter according to JIS K 7121-1987.
  • a test piece having a thickness of 0.5 mm or less is cut out from the pellet, and a test piece for 5 mg is heated from ⁇ 40 ° C. to 120 ° C. at a heating rate of 20 ° C./min under a nitrogen stream to DSC. Get a curve.
  • the temperature at the intersection of the extension line of the baseline on the low temperature side and the tangent line indicating the maximum slope at the transition portion (that is, the curved portion) is read as the glass transition temperature T g .
  • An empty container is used as a reference substance.
  • the glass transition temperature T g is the so-called extrapolation glass transition start temperature.
  • Item 6 Item 2. The method for producing pellets according to any one of Items 1 to 5, wherein the thermoplastic resin contains at least one of a polyamide resin and a polyester resin. Thereby, pellets containing at least one of a polyamide resin and a polyester resin can be obtained.
  • Item 7 Item 2. The method for producing pellets according to any one of Items 1 to 6, wherein the pellet diameter D p is 4.5 mm or less.
  • Item 8 The method for producing pellets according to any one of Items 1 to 7, wherein the step of cooling the strands includes a step of air-cooling the strands that have been water-cooled in the water tank. As a result, at least a part of the water adhering to the strand can be vaporized by the heat of the strand.
  • Item 9 One or more first guide rollers for guiding the strands in the water tank are provided in the water tank.
  • One or more second guide rollers are provided to guide the strands water-cooled in the water tank in the air.
  • Item 8. The method for producing pellets according to Item 8, wherein the angle formed by the strands before and after the second guide roller located at the most upstream is larger than the angle formed by the strands before and after the first guide roller located at the most upstream. According to Item 9, the runout of the strand can be reduced, and the strand breakage can be suppressed. This will be described.
  • the flexibility is lower than when the strands are curved by the most upstream first guide roller because the strands are solidified. Due to the low flexibility of the strands, if the bend in the most upstream second guide roller is excessively tight, the strands may not be able to follow the bend. If the strand cannot follow the bend, the strand will run out. On the other hand, according to Item 9, the angle formed by the strands before and after the second guide roller located at the most upstream is larger than the angle formed by the strands before and after the first guide roller located at the most upstream, and vice versa. Compared to the case of, the strand is easier to follow the bend in the most upstream second guide roller.
  • the angle formed by the strands before and after the first guide roller located in the most upstream is specifically among the angles formed by the strands before and after the first guide roller located in the most upstream when the strand is viewed from the side. , The size of the angle that opens toward the surface of the water.
  • the angle formed by the strands before and after the second guide roller located at the most upstream is specifically the ground among the angles formed by the strands before and after the most upstream second guide roller when the strand is viewed from the side. It is the size of the angle that opens toward.
  • Item 10 The method for producing pellets according to Item 9, wherein only one first guide roller is provided in the water tank. This allows you to limit the number of times the strands bend in water.
  • Item 11 The method for producing pellets according to any one of Items 1 to 10, wherein an extruder is used to extrude the strands. Since an extruder is used, the strands can be extruded quantitatively.
  • Item 12 Item 2. The method for producing pellets according to any one of Items 1 to 11, wherein in the step of extruding the strand, the strand is extruded into air. Since the strands are pushed into the air, the strands can dissipate heat in the air.
  • Item 13 Item 2.
  • the frequency of occurrence of hollow pellets can be reduced while keeping the water content immediately after pelletizing below a certain level.
  • the extruder 11 includes a screw (not shown) and a cylinder (not shown) surrounding the screw. That is, the extruder 11 includes a cylinder and a screw in the cylinder.
  • the extruder 11 can knead the raw materials of the composition while moving them by a rotating screw, and extrude the composition in a quantitative manner.
  • Examples of the extruder 11 include a single-screw extruder and a twin-screw extruder. Of these, a twin-screw extruder is preferable.
  • a die 13 is attached to the extruder 11.
  • the die 13 can be attached to the cylinder via an adapter.
  • the die 13 has a flow path (hereinafter, referred to as “nozzle”) for flowing the composition that has moved from the outlet of the extruder 11.
  • the outlet of the nozzle that is, the discharge port, has a circular shape.
  • the shape of the discharge port is not limited to this. For example, it may have an elliptical shape.
  • a plurality of discharge ports are provided so as to be arranged in the width direction of the die 13 (not shown). The number of discharge ports is, for example, 1 to 50, and may be 5 to 30.
  • the water tank 21 is arranged so that the strand 51 coming out of the die 13 can be received. That is, the water tank 21 is arranged downstream of the extruder 11. As the water tank 21, a strand cooling bath can be preferably used.
  • the water tank 21 contains water.
  • the water surface 25 formed by the water is below the discharge port of the die 13.
  • each guide roller 27 is arranged so as to be in contact with an upper portion of the strand 51, specifically, a portion closer to the water surface 25 in the radial direction of the strand 51.
  • the axis of each guide roller 27 extends horizontally and in the Transverse Direction (hereinafter referred to as "TD") direction.
  • TD Transverse Direction
  • One or more guide rollers 31 for guiding the strand 51 are also provided downstream of the water tank 21.
  • the number of guide rollers 31 is, for example, 1 to 10, and may be 2 to 7.
  • the most upstream guide roller 31 is referred to as a guide roller 31A.
  • Each guide roller 31 is arranged so as to be in contact with a lower portion of the strand 51, specifically, a portion closer to the ground in the radial direction of the strand 51.
  • the axis of each guide roller 31 extends horizontally and in the TD direction. Note that FIG. 1 shows a state in which a plurality of guide rollers 31, specifically two, are provided.
  • a pelletizer 41 is arranged downstream of the guide roller 31.
  • the pelletizer 41 includes a take-up roll (not shown) for picking up the strand 51 and a cutter (not shown) for cutting the picked-up strand 51.
  • the pelletizer 41 can form pellets by cutting the strand 51 with a cutter while taking it with a roll.
  • the strand 51 is extruded from the die 13 into the air by the extruder 11, enters the water in the water tank 21, travels in the water along the guide roller 27, and goes out onto the water. It travels in the air along the guide roller 31 and is cut by the pelletizer 41.
  • the method for producing pellets in the present embodiment includes a step of extruding the strand 51 made of the composition from the die 13 (hereinafter referred to as “extrusion step”) and a step of cooling while taking over the strand 51 (hereinafter referred to as “cooling step”). This includes a step of cutting the cooled strand 51 to obtain pellets (hereinafter, referred to as a “pelletizing step”).
  • the step of cooling the strand 51 is a step of drawing the strand 51 into the water in the water tank 21 and cooling it with water (hereinafter referred to as a "water cooling step”), and a step of air-cooling the water-cooled strand 51 (hereinafter referred to as “water cooling step”). , “Air cooling process”).
  • Step of extruding strands of composition (extrusion step)>
  • the raw material of the composition for example, a thermoplastic resin, and if necessary, a reinforcing material, an additive, or the like is kneaded, and the strand 51 made of the composition is extruded into the air from the discharge port of the die 13.
  • the raw material of the composition examples include a thermoplastic resin, a reinforcing material, a mold release agent, and an olefin compound. These will be described in detail later.
  • a composition can be produced by kneading the raw materials.
  • the raw material of the composition is kneaded with the extruder 11.
  • the ratio of the screw length L (mm) to the screw diameter D (mm) (hereinafter referred to as "screw L / D") is 10 to 100. It is preferable to have. When it is 100 or less, a decrease in mechanical strength of the composition due to thermal deterioration can be suppressed.
  • the nozzle of the die 13 extends at least in the vicinity of the discharge port and is inclined in the horizontal direction so as to approach the water surface 25. That is, the discharge direction of the nozzle is inclined with respect to the horizontal direction so as to approach the water surface 25.
  • the inclination of the nozzle in the vicinity of the discharge port that is, the inclination in the discharge direction is preferably 5 ° or more, more preferably 10 ° or more with respect to the horizontal direction.
  • the inclination of the nozzle is preferably 90 ° or less, more preferably 85 ° or less with respect to the horizontal direction.
  • MD Machine Direction
  • Diameter D n of the discharge port in the die 13 is preferably at least 2.0 mm, more preferably not less than 2.5 mm. When it is 2.0 mm or more, the strength of the molten portion in the strand 51 can be secured, so that the strand breakage due to insufficient strength can be suppressed.
  • the diameter D n is preferably 10 mm or less, more preferably 7 mm or less, and more preferably 5 mm or less. When it is 10 mm or less, the inside of the strand 51 can be effectively cooled, so that the solidification of the inside can be effectively promoted in the water cooling step.
  • the diameter D n refers to the maximum diameter of the discharge port when the discharge port has an elliptical shape.
  • thermoplastic resin for example, a thermoplastic resin, a reinforcing material, and an additive (for example, a mold release agent, an olefin compound, etc.) are mixed by a blender, and this is provided at the first supply port of the extruder 11.
  • an additive for example, a mold release agent, an olefin compound, etc.
  • the reinforcing material may be charged into the extruder 11 from the second supply port (hereinafter, referred to as “side port”) provided downstream of the first supply port with a feeder.
  • side port provided downstream of the first supply port with a feeder.
  • a vacuum pump is used between the side opening and the die head in order to remove volatile components and decomposed low molecular weight components and to increase the reactivity between the reinforcing material and the thermoplastic resin (for example, polyamide resin). It is preferable to perform suction by.
  • Temperature T D of the composition at the discharge port is preferably at least 180 ° C., more preferably at least 200 ° C., more preferably above 220 ° C., and even more preferably 240 ° C..
  • the temperature T D is preferably 400 ° C. or lower, more preferably 360 ° C. or lower, and even more preferably 320 ° C. or lower.
  • the temperature T D is preferably the melting point T m plus 10 ° C. or higher (that is, the sum of the melting points T m and 10 ° C. or higher), more preferably the melting point T m plus 15 ° C. or higher, and the melting point T m plus 20 ° C. or higher. More preferred. This is because the composition can be effectively melted.
  • the temperature T D is preferably the melting point T m plus 80 ° C. or lower (that is, the sum of the melting points T m and 80 ° C. or less), preferably the melting point T m plus 60 ° C. or lower, and further the melting point T m plus 50 ° C. or lower. preferable. This is because, when the temperature T D is excessively high, because the composition is significantly thermally degraded.
  • the temperature T D can be rephrased as the temperature of the strand 51 at the discharge port.
  • the temperature T D is preferably 270 ° C. or higher, more preferably 275 ° C. or higher, still more preferably 280 ° C. or higher. In this case, the temperature T D is preferably 340 ° C. or less, more preferably 320 ° C. or less, more preferably 310 ° C. or less.
  • Temperature T D when the thermoplastic resin is a polycaproamide (polyamide 6), preferably at least 230 ° C., more preferably at least 235 ° C., and even more preferably 240 ° C..
  • the temperature T D is preferably 300 ° C. or less, more preferably 280 ° C. or less, more preferably 270 ° C. or less.
  • the strand 51 extruded from the die 13 is easily broken. This is because the extruded strand 51 is composed of a melted composition.
  • the strand 51 is stronger against the stress in the tensile direction than the shear stress (specifically, the stress that causes both side portions to deviate from each other along the radial cross section of the strand 51). This is because the strand 51 is stretched by taking the strand 51 with a take-up roll, so that the polymer in the strand 51 is oriented in the traveling direction of the strand 51, that is, in the length direction of the strand 51.
  • the composition constituting the strand 51 contains glass fiber as a reinforcing material, the glass fiber is also oriented in the traveling direction of the strand 51.
  • the process of drawing the strands into the water in the water tank and cooling them with water (water cooling process)>
  • the strand 51 extruded from the die 13 is drawn into the water in the water tank 21. Since the strand 51 is drawn into the water in the water tank 21 and cooled by water, the strand 51 can be cooled isotropically in the radial direction (specifically, the radial direction of the strand 51). If, instead of such a water cooling process, the strand 51 is placed on a conveyor belt and conveyed while being cooled by blowing water, air, or the like, the strand 51 is isotropic in the radial direction. It is difficult to cool the strand 51.
  • Tap water, well water, rainwater, pure water, etc. can be used as the water to be put into the water tank 21. Chemicals or the like may be added to the water in the water tank 21.
  • cooling rate the rate at which the strand 51 is cooled in the water cooling process
  • the solidification rate of the surface layer portion in water cooling and the inside in water cooling that is, the shaft rather than the surface layer portion. Since the difference from the solidification rate of the (closer part) is excessively widened, there is a possibility that the inside may solidify and shrink with a greater delay than the surface layer part during water cooling.
  • Water temperature in the water tank (hereinafter, referred to as "water temperature”.)
  • T W is, 3 ° C., more preferably equal to or greater than 10 ° C., more preferably above 15 ° C., more preferably above 20 ° C., 50 ° C. or higher Is even more preferable.
  • the temperature is 3 ° C or higher, the cooling rate of the water cooling process is slower than that of less than 3 ° C. it can.
  • Water temperature T W is preferably 80 ° C. or less, more preferably 60 ° C. or less, more preferably 55 ° C. or less. When the temperature is 80 ° C. or lower, the strand 51 can be effectively cooled.
  • Water temperature T W may be higher than the glass transition temperature T g of the composition, although may be low, preferably higher than the glass transition temperature T g.
  • the cooling rate is slow, and solidification rate of the surface layer portion in a water-cooled, the difference between the internal solidification rate in a water-cooled small can do.
  • the water temperature TW may be, for example, the glass transition temperature T g of the composition plus 10 ° C. or higher (that is, the sum of the glass transition temperature T g and 10 ° C. or higher).
  • the water cooling step, the strands 51 it is preferable to enter the following 85 ° water entering water angle [delta] 1 45 ° or more in the water tank 21.
  • the strand 51 enters the water in the water tank 21 at a water entry angle of ⁇ 1 45 ° or more and 85 ° or less, the shear stress generated by the water entry (specifically, both side portions are displaced from each other along the radial cross section of the strand 51). Since it is possible to reduce the stress that causes the shear stress, it is possible to suppress the strand breakage caused by such a shear stress.
  • the water entry angle ⁇ 1 is preferably 50 ° or more, more preferably 55 ° or more.
  • the water entry angle ⁇ 1 is the size of an acute angle formed by the strand 51 intersecting the water surface 25 when the strand 51 is viewed from the side. That is, the water entry angle ⁇ 1 is the size of an acute angle formed by the strand 51 intersecting the water surface 25 when the strand 51 is viewed in the axial direction of the guide roller 27.
  • the water entry angle ⁇ 1 is preferably 80 ° or less, more preferably 70 ° or less, and even more preferably 60 ° or less.
  • the strand 51 that has entered the water is curved by the guide roller 27A, but if the curvature is steep, the curvature may remain excessively on the strand 51. This is because since the strand 51 is composed of a composition, the flexibility decreases as the solidification of the strand 51 progresses by water cooling. Due to the curvature remaining on the strand 51, the runout of the strand 51, that is, the violence becomes large. The runout of the strand 51 causes the strand to break. This is because, due to the runout of the strand 51, a stress (shear stress) is applied to the strand 51 so that the portion of the strand 51 that does not exit the discharge port and the portion of the strand 51 that exits the discharge port are displaced from each other. ..
  • the angle ⁇ 2A formed by the strand 51 around the guide roller 27A is preferably 100 ° or more, more preferably 110 ° or more.
  • the angle ⁇ 2A is preferably less than 180 °.
  • the angle ⁇ 2A is more preferably 160 ° or less, further preferably 150 ° or less, further preferably 140 ° or less, still more preferably 130 ° or less in order to firmly contact the strand 51 and the guide roller 27A.
  • the strand 51 and the guide roller 27A can be brought into close contact with each other, so that the runout or violence of the strand 51 that occurs downstream of the guide roller 27A is transmitted upstream of the guide roller 27A. It can be difficult. Therefore, strand breakage can be suppressed more effectively. Moreover, since the strand 51 and the guide roller 27A can be brought into close contact with each other, the stress generated in the strand 51 due to the contact with the guide roller 27A can be diffused.
  • the angle ⁇ 2A is the size of the angle formed by the strand 51 before and after the guide roller 27A, which opens toward the water surface 25 when the strand 51 is viewed from the side.
  • the angle ⁇ 2B formed by the strand 51 around the guide roller 27B is preferably 100 ° or more.
  • the angle ⁇ 2B is preferably less than 180 °, more preferably 179 ° or less, and even more preferably 178 ° or less.
  • the angle ⁇ 2B is the size of the angle formed by the strand 51 before and after the guide roller 27B, which opens toward the water surface 25 when the strand 51 is viewed from the side.
  • the diameter of the guide roller 27A is preferably 1 cm or more, more preferably 2 cm or more. As the diameter of the guide roller 27A is larger, the contact area between the guide roller 27A and the strand 51 tends to increase. Therefore, from the discharge port of the die 13 to the contact with the guide roller 27A. The runout of (part) can be reduced.
  • the diameter of the guide roller 27A may be, for example, 20 cm or less, or 15 cm or less.
  • the diameter of each guide roller 27 is preferably 1 cm or more, more preferably 2 cm or more.
  • the diameter of each guide roller 27 may be, for example, 20 cm or less, or 15 cm or less.
  • the diameters of the guide rollers 27 may be equal to or different from each other.
  • the length L of the strand 51 immersed in water in the water tank 21 (hereinafter, referred to as “water immersion length”) L satisfies the formula 1.
  • the water immersion length L is the length of the strand 51 itself from the point where the strand 51 enters the water to the point where the strand 51 exits the water.
  • L is represented by cm.
  • L 1 and L 2 are as follows.
  • L 1 K 1 ⁇ D p ⁇ ⁇ (T D -T C2) / (T D -T W) ⁇ ⁇ v ( Equation 2)
  • L 2 K 2 x D p x v (Equation 3)
  • K 1 is 0.74.
  • K 1 (that is, 0.74) is determined so that the unit of the numerical value obtained by calculating the right side of Equation 2 is cm.
  • D p is the diameter of the pellet and is represented by mm.
  • T D is the temperature of the composition at the discharge port of the die 13, is represented by ° C..
  • TC2 is the falling crystallization temperature of the composition, expressed in ° C.
  • TW is the temperature of the water in the water tank 21 (that is, the water temperature), and is represented by ° C.
  • v is the rate at which the strand 51 is picked up and is expressed in cm / sec.
  • K 2 is 0.37.
  • the value of K 2 (that is, 0.37) is determined so that the unit of the numerical value obtained by calculating the right side of Equation 3 is cm.
  • the frequency of occurrence of hollow pellets can be reduced.
  • the mechanism is as follows. ------ When the water immersion length L is L 1 or more, not only the solidification of the surface layer portion of the strand 51 is started during water cooling, but also the solidification of the inside of the strand 51 (that is, the portion closer to the axis than the surface layer portion) is also possible. Can be started. This is because L 1 indicates the length of the strand 51 in water (hereinafter referred to as “underwater length”) to be immersed in the water in the water tank 21 in order to initiate solidification inside the strand 51 during water cooling. Because. This will be described in detail later.
  • the difference between the solidification rate of the surface layer and the solidification rate of the inside is compared with the case where the solidification of the inside is started during air cooling. Can be shortened. This is because water cooling has a higher cooling effect than air cooling, so that the inside can be effectively cooled.
  • By making it possible to reduce the difference between the solidification rate of the surface layer portion and the solidification rate of the inside it is possible to prevent the inside from solidifying and shrinking with a greater delay than that of the surface layer portion, so that a cavity is generated in the strand 51. Can be prevented.
  • L 1 indicates the underwater length of the strand 51 to be immersed in the water in the water tank 21 in order to initiate the solidification of the inside of the strand 51 during water cooling.
  • the reason is as follows. ------ With respect to the equation 2 for deriving L 1 , since TC 2 is the falling crystallization temperature, TC 2 can be regarded as the temperature at which solidification of the strand 51 starts, so that T D -TC 2 is the temperature at the discharge port. And the temperature at which solidification begins. On the other hand, as the opening of T D and T W is large, the cooling rate of the strand 51 is fast, T D -T W can Mitateru the cooling rate of the strand 51.
  • (T D -T C2) / (T D -T W) indicates an index of a time required for the strand 51 begins to solidify. This is because the T D -T C2 as distance (distance on the temperature), by dividing by T D -T W as cooling rate, be obtained an indication of the time required for the strand 51 begins to solidify Because it can be done.
  • v is the speed at which the strand 51 is picked up, that is, the speed at which the strand 51 moves in the water tank 21.
  • the underwater length of the strand 51 to be immersed in water in the water tank 21 to initiate solidification of the "inside" of the strand 51 is proportional to the diameter of the strand 51 in water. This is because the larger the diameter of the strand 51 in water, the longer it takes to start solidification of the "inside” of the strand 51, so that the length of the strand 51 to be immersed in the water in the water tank 21 also becomes longer. ..
  • D p ⁇ ⁇ (T D -T C2) / (T D -T W) ⁇ ⁇ v can be said to be an indicator of the water length of the strand 51 to be immersed in the water in the water tank 21 to initiate solidification of the "inside" of the strand 51 in the water-cooled.
  • coefficients empirically determined, i.e. by the application of K 1 solidification of "inside" the strands 51
  • the underwater length of the strand 51 itself that is, L 1, to be immersed in the water in the water tank 21 is obtained in order to start the process during water cooling.
  • pellets having a water content of less than a certain level immediately after pelletizing for example, pellets having a water content of less than 0.10% by mass can be obtained.
  • L 2 indicates the length of the strand 51 in water at which the water absorption rate in water cooling is less than 0.10% by mass (this will be described in detail later).
  • the strands hardly absorb water during air cooling, it can be said that the water absorption rate in water cooling controls the water content immediately after pelletizing.
  • the water absorption rate is used in the sense of (mass of water absorbed by the strand 51 during water cooling) / (net mass of the strand 51).
  • water absorption mass the mass of water absorbed by the strand 51 during water cooling
  • net mass the mass of the strand 51
  • a drying facility for example, the operation of applying drying air to the pellets
  • L 2 indicates the length of the strand 51 in water at which the water absorption rate in water cooling is less than 0.10% by mass.
  • the reason is as follows. ------ The water absorption mass constituting the water absorption rate (water absorption mass / net mass) can be roughly expressed by the water absorption rate ⁇ the immersion time. This is because the faster the water absorption rate, the larger the water absorption mass, and the longer the immersion time, the larger the water absorption mass. Since the water absorption rate increases as the surface area of the strand 51 increases, it can be roughly expressed by the underwater length of k ⁇ ⁇ ⁇ D p ⁇ strand 51 using the formula of the side area of the cylinder.
  • k is a coefficient and ⁇ is pi.
  • the water absorption mass can be roughly expressed by the following formula.
  • Water absorption mass k ⁇ ⁇ ⁇ D p ⁇ length of strand 51 in water ⁇ immersion time
  • d is the density of the strand 51. Therefore, the water absorption rate (water absorption mass / net mass) can be roughly expressed by the following formula.
  • k ′′ is a coefficient.
  • Air-cooling process of strands after water cooling (air-cooling process)>
  • the water-cooled strand 51 is air-cooled.
  • at least a part of the water adhering to the strand 51 can be vaporized by the heat of the strand 51.
  • water absorption after pelletizing can be suppressed.
  • the wind pressure of the blower is 0.1 MPa or more and the air volume is 5 m 3 / min or more, the moisture adhering to the strand 51 can be effectively blown off.
  • the water-cooled strand 51 is curved by the guide roller 31A, but if the curvature is steep, the strand 51 tends to run out. This is because the strand 51 is not very flexible because it has been solidified by water cooling.
  • the angle ⁇ 3 formed by the strand 51 around the guide roller 31A is preferably 140 ° or more, more preferably 150 ° or more.
  • the angle ⁇ 3 is preferably 179 ° or less, more preferably 175 ° or less, and even more preferably 170 ° or less.
  • the angle ⁇ 3 is the size of the angle formed by the strand 51 before and after the guide roller 31A that opens toward the ground when the strand 51 is viewed from the side.
  • the angle ⁇ 3 is larger than the angle ⁇ 2A .
  • the runout of the strand 51 can be reduced. This will be described.
  • the flexibility is lower than when the strand 51 is curved by the guide roller 27A because the strand 51 is solidified. Due to the low flexibility of the strand 51, if the guide roller 31A bends excessively, the strand 51 may not be able to follow the bend. If the strand 51 cannot follow the bend, the strand 51 will run out.
  • the angle [delta] 3 is greater than the angle [delta] 2A, vice versa (i.e., the angle [delta] 3 is smaller than the angle [delta] 2A) as compared to the strand 51, follow the bending of the guide rollers 31A It's easy to do. Therefore, when the angle ⁇ 3 is larger than the angle ⁇ 2A , the runout of the strand 51 can be reduced as compared with the opposite case.
  • the diameter of the guide roller 31A is preferably 1 cm or more, more preferably 2 cm or more.
  • the diameter of the guide roller 31A may be, for example, 20 cm or less, or 15 cm or less.
  • each guide roller 31 is preferably 1 cm or more, more preferably 2 cm or more.
  • the diameter of each guide roller 31 may be, for example, 20 cm or less, or 15 cm or less.
  • the diameters of the guide rollers 31 may be equal to or different from each other.
  • the air-cooled length of the strand 51 can be set as appropriate.
  • the air-cooled length is the length of the strand 51 itself from the point where the strand 51 comes out on the water to the point where it is cut.
  • the air cooling length is preferably set so that the strand 51 is lowered to a temperature at which it can be cut by the pelletizer 41.
  • Step of cutting air-cooled strands to obtain pellets (pelletizing step)>
  • the air-cooled strand 51 is cut with a pelletizer 41 to obtain pellets.
  • the surface temperature of the strands 51 is preferably lower than the glass transition temperature T g. As a result, cutting defects of the strand 51 can be suppressed, so that the frequency of occurrence of twin pellets composed of two or more connected pellets can be reduced.
  • Pellets are usually columnar, specifically straight columnar.
  • the shape of the pellet cross section (hereinafter referred to as "cross-sectional shape") usually has an elliptical shape. This is because the cross-sectional shape of the strand 51 becomes elliptical due to the pressure received by the guide roller 27.
  • the cross-sectional shape of the pellet is not limited to this. For example, it may be circular.
  • the pellet cross section is a cut end formed by the pelletizer 41.
  • the diameter D p of the pellet is smaller than the diameter D n of the discharge port. This is because by taking the strand 51 with a take-up roll, tension is applied to the strand 51, so that the strand 51 extends at the molten portion (that is, the strand 51 extends at least at the portion from the die 13 to the water surface 25). ..
  • the pellet diameter D p is obtained by measuring the maximum diameter of the pellet cross section (the cut end formed by the pelletizer 41) and the minimum diameter of the pellet cross section with a caliper and dividing the sum of the maximum diameter and the minimum diameter by 2. ..
  • the diameter D p of the pellets is an average value for 100 pellets.
  • the diameter D p of the pellet is preferably 0.5 mm or more, more preferably 1.0 mm or more, further preferably 1.5 mm or more, still more preferably 2.0 mm or more.
  • the diameter D p of the pellet is preferably 4.5 mm or less, more preferably 4.0 mm or less, and further preferably 3.5 mm or less.
  • the flatness of the pellets is preferably 2.0 or less, more preferably 1.9 or less.
  • the smaller the flatness of the pellet the smaller the specific surface area of the pellet tends to be.
  • the size of the specific surface area of the pellet is limited, so that the pellet absorbs water ( For example, the water absorption of the pellets until the pellets are packed in a bag) can be reduced.
  • the flatness of the pellets may be, for example, 1.2 or more, 1.3 or more, or 1.4 or more.
  • the flatness of the pellet is a value obtained by dividing the maximum diameter of the pellet cross section by the minimum diameter of the pellet cross section.
  • the flatness of the pellets is an average value for 100 pellets.
  • the standard deviation is preferably 0.20 or less, more preferably 0.15 or less, further preferably 0.10 or less, still more preferably 0.08 or less.
  • the length of the pellets is preferably 1 mm or more, more preferably 1.5 mm or more, further preferably 2 mm or more, still more preferably 2.5 mm or more.
  • the length of the pellet is preferably 15 mm or less, more preferably 10 mm or less, further preferably 6 mm or less, further preferably 5 mm or less, still more preferably 4 mm or less.
  • the moisture content of the pellets is preferably less than 0.10% by mass. If it is less than 0.10% by mass, the operation of drying the pellets using a drying facility can be omitted. Therefore, the installation of the drying equipment and the running cost for the drying operation can be omitted.
  • the pellets may be left to stand while being exposed to dry air as needed. By leaving the pellets to stand, at least a part of the water adhering to the pellets can be vaporized by the heat of the pellets. The pellets are sorted as needed and packed in bags as needed.
  • Ratio of pellet diameter D p to discharge port diameter D n (D p / D n )> The greater the tension applied to the molten portion of the strand 51, the smaller the ratio (D p / D n ) of the pellet diameter D p to the discharge port diameter D n . Therefore, the ratio (D p / D n ) can be used as an index of the tension applied to the molten portion of the strand 51.
  • the ratio (D p / D n ) can be adjusted by the speed at which the strand 51 is picked up (pick-up speed).
  • the ratio (D p / D n ) is preferably 0.45 or more, more preferably 0.50 or more, and even more preferably 0.53 or more. When it is 0.45 or more, it is possible to prevent excessive tension from being applied to the molten portion of the strand 51, so that it is possible to suppress the strand breakage.
  • the ratio (D p / D n ) is preferably 0.97 or less, more preferably 0.95 or less, and even more preferably 0.93 or less. When it is 0.97 or less, a tension enough to suppress the runout of the molten portion of the strand 51 can be applied to the molten portion of the strand 51.
  • the pick-up speed v is 20 cm / sec or more, preferably 30 cm / sec or more. When it is 20 cm / sec or more, the pellet production amount per unit time is excellent.
  • the pick-up speed v is 140 cm / sec or less, preferably 130 cm / sec or less.
  • the glass transition temperature T g i.e. a glass transition temperature T g of the pellets of the composition, for example, may also be 20 ° C. or higher, it may also be 30 ° C. or more, may be 40 ° C. or higher.
  • the glass transition temperature Tg may be, for example, 80 ° C. or lower, 70 ° C. or lower, or 60 ° C. or lower.
  • the melting point T m of the composition that is, the melting point T m of the pellet may be, for example, 180 ° C. or higher, 190 ° C. or higher, or 200 ° C. or higher.
  • the melting point T m may be, for example, 300 ° C. or lower, 290 ° C. or lower, 280 ° C. or lower, or 270 ° C. or lower.
  • Lowering crystallization temperature T C2 i.e. lowering the crystallization temperature T C2 of the pellets of the composition, for example, may also be 140 ° C. or higher, may also be 160 ° C. or higher, it may be 180 ° C. or higher.
  • the falling crystallization temperature TC2 may be, for example, 280 ° C. or lower, 270 ° C. or lower, 260 ° C. or lower, or 250 ° C. or lower.
  • the bending fracture strain of the composition is preferably 10% or more.
  • the bending fracture strain is 10% or more, hollow pellets are more likely to occur as compared with the case where it is less than 10%. This is because when the bending fracture strain is 10% or more, the amount of the reinforcing material tends to be small and the content of the thermoplastic resin tends to be large as compared with the case where it is less than 10%.
  • the bending fracture strain is preferably 20% or more, more preferably 30% or more, still more preferably 40% or more.
  • the bending fracture strain may be 80% or less, or 70% or less.
  • the bending fracture strain can be adjusted by adjusting the amount of reinforcing material. Bending fracture strain tends to decrease as the amount of reinforcing material increases.
  • the bending fracture strain of the composition is determined according to JIS K7171: 2016. Specifically, a test piece for a 3-point bending test is prepared from pellets, and a 3-point bending test is performed to determine bending fracture strain.
  • composition and its raw materials The composition comprises a thermoplastic resin and, if necessary, a reinforcing material.
  • thermoplastic resin is not particularly limited, and is, for example, polyamide (PA), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), aramid resin, polyetheretherketone (PEEK), polyetherketone (PEK), polyetherimide ().
  • PA polyamide
  • PPS polyphenylene sulfide
  • LCP liquid crystal polymer
  • aramid resin polyetheretherketone
  • PEEK polyetherketone
  • PEK polyetherketone
  • polyetherimide polyetherimide
  • thermoplastic polyimide polyamideimide
  • PAI polyetherketoneketone
  • PPE polyphenylene ether
  • PES polyethersulfone
  • PSU polyallylate
  • PET Polycarbonate
  • POM polyoxymethylene
  • POM polypropylene
  • PE polyethylene
  • TPX polymethylpentene
  • PS polystyrene
  • AS acrylonitrile-styrene copolymer
  • ABS acrylonitrile -Butadiene-styrene copolymer
  • fluororesin polyacrylate and the like
  • polyamide and polyester are preferable, and polyamide is particularly preferable. Only one type of thermoplastic resin may be used alone, or several types may be used in combination.
  • the polyamide is not particularly limited, and for example, polycaproamide (polyamide 6), polytetramethylene adipamide (polyamide 46), polyhexamethylene adipamide (polyamide 66), polyundecamethylene adipamide (polyamide 116).
  • Polymethoxylylen adipamide (polyamide MXD6), polyparaxylylene adipamide (polyamide PXD6), polytetramethylene sebacamide (polyamide 410), polyhexamethylene sebacamide (polyamide 610), polydecamethylene Adipamide (polyamide 106), polydecamethylene sebacamide (polyamide 1010), polyhexamethylene dodecamide (polyamide 612), polydecamethylene dodecamide (polyamide 1012), polyhexamethylene isophthalamide (polyamide 6I), poly Tetramethylene terephthalamide (polyamide 4T), polypentamethylene terephthalamide (polyamide 5T), poly-2-methylpentamethylene terephthalamide (polyamide M-5T), polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene hexahydro Telephthalamide (polyamide 6T (H)), polynonamethylene terephthalamide (poly
  • the content of the thermoplastic resin is preferably 55% by mass or more, more preferably 65% by mass or more, further preferably 75% by mass or more, still more preferably 80% by mass or more, based on 100% by mass of the composition.
  • the content of the thermoplastic resin may be 85% by mass or more, or 90% by mass or more.
  • the reinforcing material is a substance capable of enhancing the mechanical properties, specifically, the mechanical properties of the molded product obtained by molding the pellets.
  • the shape of the reinforcing material is not particularly limited, and may be fibrous or granular, for example.
  • the reinforcing material is not particularly limited, and for example, glass fiber, acicular warastonite, mica, talc, unbaked clay, whisker (for example, potassium titanate), carbon fiber, ceramic fiber, silica, alumina, kaolin, quartz, etc. Examples thereof include powdered glass (milled fiber), graphite, glass flakes, calcium carbonate, barium sulfate, carbon black, and metal powder.
  • inorganic reinforcing materials such as glass fiber and talc are preferable, glass fiber and talc are more preferable, and glass fiber is further preferable. Only one type of reinforcing material may be used alone, or several types may be used in combination.
  • fibrous reinforcing material examples include inorganic fibers such as glass fibers, organic fibers, and metal fibers.
  • examples of the inorganic fiber include glass fiber, carbon fiber, ceramic fiber, and potassium titanate. Of these, glass fiber is preferable.
  • glass fiber examples include chopped strand-shaped glass fiber.
  • the diameter of the glass fiber is preferably 1 ⁇ m to 100 ⁇ m.
  • the “glass fiber diameter” is the diameter in a cross section perpendicular to the longitudinal direction of the glass fiber. When there is a maximum diameter and a minimum diameter in the cross section, the “glass fiber diameter” refers to the maximum diameter.
  • the fiber length of the glass fiber is preferably 0.1 mm to 10 mm.
  • the average particle size of a granular reinforcing material such as talc is preferably 1 ⁇ m to 100 ⁇ m.
  • the average particle size is measured by a laser diffraction type particle size distribution measuring device "SALD-2300" manufactured by Shimadzu Corporation.
  • the reinforcing material may be subjected to a silane treatment such as an aminosilane treatment. That is, the reinforcing material may be surface-treated with a coupling agent (specifically, a silane coupling agent).
  • a silane treatment such as an aminosilane treatment. That is, the reinforcing material may be surface-treated with a coupling agent (specifically, a silane coupling agent).
  • the content of the reinforcing material is preferably 30% by mass or less, more preferably 20% by mass or less, further preferably 10% by mass or less, and 5% by mass or less in 100% by mass of the composition. Is even more preferable.
  • the coupling agent can be pre-adhered to the reinforcing material, in order to further improve the wettability of the reinforcing material to the thermoplastic resin, a coupling agent is used separately from the coupling agent pre-adhered to the reinforcing material. It is preferable to add it.
  • the amount of the coupling agent added is preferably 0.1 part by mass or more, and more preferably 0.2 part by mass or more with respect to 100 parts by mass of the reinforcing material.
  • the amount of the coupling agent added is preferably 3.0 parts by mass or less, more preferably 2.0 parts by mass or less, based on 100 parts by mass of the reinforcing material.
  • a coupling agent that is, a coupling agent for addition, a silane coupling agent can be mentioned. Only one type of coupling agent may be used alone, or several types may be used in combination.
  • composition may contain a reinforcing material, it is preferable that the composition does not contain a reinforcing material.
  • the composition may further contain a filler for improving properties other than mechanical properties (eg, electrical properties).
  • the composition preferably further contains a stabilizer.
  • Stabilizers include organic antioxidants such as hindered phenolic antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants, heat stabilizers, and photostabilizers such as hindered amines, benzophenones, and imidazoles. Examples thereof include agents, ultraviolet absorbers, metal deactivators, copper compounds, alkali metal halide compounds, and the like. Of these, copper compounds are preferable. Only one type of stabilizer may be used alone, or several types may be used in combination. Although the content of the stabilizer can be adjusted as appropriate, it is preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less in 100% by mass of the composition.
  • the "stabilizer content” is the total content of the stabilizers when the composition contains a plurality of stabilizers.
  • Copper compounds that can be used as stabilizers include cuprous chloride, cuprous bromide, cuprous iodide, cupric chloride, cupric bromide, cupric iodide, cupric phosphate, Copper salts of organic carboxylic acids such as cupric pyrophosphate, copper sulfide, copper nitrate and copper acetate can be used. Only one type of copper compound may be used alone, or several types may be used in combination.
  • the composition can contain an olefin compound for the purpose of modifying properties such as impact resistance and flexibility.
  • the olefin compound preferably has a carboxylic acid group and / or a carboxylic acid anhydride group.
  • examples of such olefin compounds include modified polyolefins and modified styrene copolymers.
  • the modified polyolefin is an ⁇ -olefin-based polymer in which a monomer having a carboxylic acid group and / or a carboxylic acid anhydride group is contained in an unmodified polymer molecular chain by copolymerization, graft polymerization, or the like.
  • the polymer includes a copolymer.
  • the modified styrene-based copolymer is a styrene-based copolymer in which a monomer having a carboxylic acid group and / or a carboxylic acid anhydride group is contained in an unmodified polymer molecular chain by copolymerization or graft polymerization. Is.
  • Examples of the unmodified polymer that can be used to obtain the modified polyolefin and the modified styrene-based polymer include homopolymers such as polyethylene, polypropylene, polybutene-1, polypentene-1, and polymethylpentene, as well as ethylene and propylene.
  • polystyrene resin examples include ethylene / propylene copolymer, ethylene / butene-1 copolymer, ethylene / hexene-1 copolymer, ethylene / propylene / dicyclopentadiene copolymer, ethylene / propylene / 5-ethylidene-2.
  • -Norbornene copolymer unhydrogenated or hydrogenated polybutadiene, unhydrogenated or hydrogenated styrene / isoprene / styrene triblock copolymer, unhydrogenated or hydrogenated styrene / butadiene / styrene triblock copolymer, etc. Be done.
  • the diene-based elastoma is an AB-type or AB-A'type block copolymer elastic composed of a vinyl-based aromatic hydrocarbon and a conjugated diene, and the terminal blocks A and A'are the same.
  • the diene-based elastoma may be different, and examples thereof include thermoplastic homopolymers or copolymers derived from vinyl-based aromatic hydrocarbons in which the aromatic moiety may be monocyclic or polycyclic.
  • vinyl-based aromatic hydrocarbons include styrene, ⁇ -methylstyrene, vinyltoluene, vinylxylene, ethylvinylxylene, vinylnaphthalene and mixtures thereof.
  • the intermediate polymer block B is composed of conjugated diene-based hydrocarbons, and examples thereof include polymers derived from 1,3-butadiene, 2,3-dimethylbutadiene, isoprene, 1,3-pentadiene and mixtures thereof. Further, it is also possible to use the intermediate polymer block B of the block copolymer that has been hydrogenated.
  • the method for introducing a carboxylic acid group and / or a carboxylic acid anhydride group into the unmodified polymer is not particularly limited, and a method such as copolymerization or graft introduction into the unmodified polyolefin using a radical initiator can be used. it can.
  • modified polyolefin and styrene-based polymers include maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, ethylene / acrylic acid copolymers, ethylene / methacrylic acid copolymers, and the carboxylic acid moiety in these copolymers.
  • the content of the olefin compound is preferably 3% by mass or more, more preferably 6% by mass or more, based on 100% by mass of the composition.
  • the content of the olefin compound is preferably 20% by mass or less, more preferably 15% by mass or less, and further preferably 10% by mass or less.
  • the composition can further contain a mold release agent, a flame retardant, a flame retardant aid, a crystal nucleating agent, a lubricant, a flame retardant, an antistatic agent, a pigment, a dye and the like. From these, one or any combination can be selected and used.
  • the release agent include long chain fatty acids or esters and metal salts thereof, amide compounds, polyethylene waxes, silicones, polyethylene oxides and the like.
  • the long-chain fatty acid is particularly preferably having 12 or more carbon atoms, and examples thereof include stearic acid, 12-hydroxystearic acid, behenic acid, and montanic acid.
  • Partial or total carboxylic acids may be esterified with monoglycols or polyglycols, or may form metal salts.
  • the amide compound include ethylenebisterephthalamide and methylenebisstearylamide. These release agents may be used alone or as a mixture.
  • the content of the release agent is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, based on 100% by mass of the composition.
  • the content of the release agent is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, still more preferably 1.0% by mass or less in 100% by mass of the composition.
  • the configuration in which the nozzle of the die 13 extends at least in the vicinity of the discharge port at an angle with respect to the horizontal direction so as to approach the water surface 25 has been described.
  • the above-described embodiment is not limited to this configuration.
  • the nozzle of the die 13 may extend at least in the vicinity of the discharge port without being inclined in the horizontal direction. It is not necessary for the nozzle to extend from end to end in the MD direction without tilting in the horizontal direction.
  • the configuration in which the water entry angle ⁇ 1 is 45 ° or more and 85 ° or less has been described.
  • the above-described embodiment is not limited to this configuration.
  • the entry angle ⁇ 1 may be less than 45 ° or more than 85 °.
  • the configuration in which the angle ⁇ 2A is 100 ° or more and less than 180 ° has been described.
  • the above-described embodiment is not limited to this configuration.
  • the angle ⁇ 2A may be less than 100 ° or more than 180 °.
  • the configuration in which the angle ⁇ 2B is 100 ° or more and less than 180 ° has been described.
  • the above-described embodiment is not limited to this configuration.
  • the angle ⁇ 2B may be less than 100 ° or more than 180 °.
  • one guide roller 27 (27A) may be provided in the water tank 21.
  • the angle ⁇ 2A is more preferably 150 ° or less, further preferably 140 ° or less, still more preferably 130 ° or less.
  • the strand 51 and the guide roller 27A can be brought into close contact with each other, so that the runout or violence of the strand 51 that occurs downstream of the guide roller 27A is less likely to be transmitted upstream of the guide roller 27A. can do. Therefore, strand breakage can be suppressed more effectively. Moreover, since the strand 51 and the guide roller 27A can be brought into close contact with each other, the stress generated in the strand 51 due to the contact with the guide roller 27A can be diffused.
  • each guide roller 27 is arranged so as to be in contact with the upper portion of the strand 51, specifically, the portion closer to the water surface 25 in the radial direction of the strand 51 has been described.
  • the above-described embodiment is not limited to this configuration.
  • the configuration in which a plurality of guide rollers 31 are provided downstream of the water tank 21 has been described.
  • the above-described embodiment is not limited to this configuration.
  • it may be configured that only one guide roller 31 is provided downstream of the water tank 21, or it may be configured that the guide roller 31 is not provided.
  • each guide roller 31 is arranged so as to be in contact with the lower portion of the strand 51, specifically, the portion closer to the ground in the radial direction of the strand 51.
  • the above-described embodiment is not limited to this configuration.
  • the configuration in which the air-cooled strand 51 is cut to obtain pellets has been described.
  • the above-described embodiment is not limited to this configuration.
  • the air-cooled strand 51 may be further water-cooled.
  • the configuration in which the ratio (D p / D n ) is 0.45 or more and 0.97 or less has been described.
  • the above-described embodiment is not limited to this configuration.
  • the ratio (D p / D n ) may be less than 0.45 or greater than 0.97.
  • the configuration in which the diameter D p of the pellet is 4.5 mm or less has been described.
  • the above-described embodiment is not limited to this configuration.
  • the diameter D p of the pellet may exceed 4.5 mm.
  • the temperature of the composition at the outlet T D was measured with a thermocouple thermometer provided at the discharge port of the die.
  • Water temperature TW Water temperature T W was measured with a water temperature gauge provided in the water tank.
  • Water entry angle ⁇ 1 , angle ⁇ 2A , and angle ⁇ 3 A polyester film with a width of 20 cm (“E5000” manufactured by Toyobo Co., Ltd., thickness 100 ⁇ m) was stretched along the path of the strand from the discharge port of the die to the inlet of the pelletizer. The water entry angle ⁇ 1 , the angle ⁇ 2A , and the angle ⁇ 3 formed of the polyester film stretched in this manner were read by an angle protractor.
  • Moisture content The water content of the pellets immediately after pelletizing was measured at 200 ° C. using a Karl Fischer type moisture content meter (manufactured by Mitsubishi Chemical Corporation, CA-100 type).
  • Pellet diameter D p The diameter D p of the pellet was determined by measuring the maximum diameter of the pellet cross section (cut end formed by the pelletizer) and the minimum diameter of the pellet cross section with a caliper and dividing the sum of the maximum diameter and the minimum diameter by two. Table 1 shows the average value of 100 pellets as the pellet diameter D p .
  • Hollow pellet content (number of hollow pellets / 500) x 100
  • the glass transition temperature T g was measured with a differential scanning calorimeter (“EXSTAR6000” manufactured by Seiko Instruments) according to JIS K 7121-1987. Specifically, a test piece having a thickness of 0.5 mm or less is cut out from the pellet, and a test piece for 5 mg is heated from ⁇ 40 ° C. to 120 ° C. at a heating rate of 20 ° C./min under a nitrogen stream to DSC. I got a curve. And extension of the cold side of the baseline, the transition portion (i.e., curved portion) temperature at the intersection of the tangential line showing the maximum inclination in the (so-called extrapolated glass transition initiation temperature) was read as the glass transition temperature T g. An empty container was used as a reference substance.
  • EXSTAR6000 manufactured by Seiko Instruments
  • the melting point T m was measured with a differential scanning calorimeter (“EXSTAR6000” manufactured by Seiko Instruments) according to JIS K 7121-1987. Specifically, a test piece having a thickness of 0.5 mm or less was cut out from the pellet, and the test piece for 5 mg was heated at 20 ° C./min under a nitrogen stream to obtain a DSC curve. The peak top temperature of the endothermic peak at the time of temperature rise (so-called melting peak temperature) was read as the melting point T m . An empty container was used as a reference substance.
  • Falling crystallization temperature TC2 Lowering the crystallization temperature T C2, in accordance with JIS K 7121-1987, measured by differential scanning calorimeter (manufactured by Seiko Instruments Inc. "EXSTAR6000"). Specifically, a test piece having a thickness of 0.5 mm or less is cut out from the pellet, and the test piece for 5 mg is heated to 300 ° C. at a heating rate of 20 ° C./min under a nitrogen stream, and then under a nitrogen stream. After holding at that temperature (300 ° C.) for 5 minutes, the temperature was lowered to 100 ° C. at a rate of 10 ° C./min under a nitrogen stream. In the DSC curve obtained by this, a peak top temperature of the maximum exothermic peak at the time of cooling (so-called crystallization peak temperature), was read as a drop crystallization temperature T C2. An empty container was used as a reference substance.
  • Test piece for 3-point bending test Length 100 mm, width 10 mm, thickness 4 mm Distance between fulcrums 64 mm Test speed 2 mm / min
  • the screw L / D34 is supplied to the main supply port of a twin-screw extruder (“TEM48BS” manufactured by Toshiba Machine Co., Ltd.), melt-kneaded, and 10 discharge ports with a diameter of D n 4.5 mm are provided. Strands were ejected from the die having.
  • TEM48BS twin-screw extruder
  • the strands coming out of the die were drawn into a water tank and cooled with water, the water-cooled strands were air-cooled, and the cooled strands were cut into pellets with a pelletizer to produce pellets.
  • the operations up to this point were performed under the conditions shown in Table 1 using the equipment configuration shown in FIG.
  • the diameter of each guide roller used in the water cooling process and the air cooling process was 4.8 cm.
  • injection molding is performed at a cylinder temperature of 285 ° C. and a mold temperature of 80 ° C. using an injection molding machine (“IS80” manufactured by Toshiba Machine Co., Ltd.) to prepare a test piece for a 3-point bending test. did.
  • Comparative Example 1 in which the water immersion length L was less than L 1 , the frequency of occurrence of hollow pellets was higher than in Examples.
  • Comparative Example 2 in which the water immersion length L exceeded L 2 , the water content of the pellet immediately after pelletizing was higher than that in Example.
  • the method for producing pellets in the present embodiment is industrially applicable because the frequency of occurrence of hollow pellets can be reduced.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Abstract

L'invention concerne un procédé de production de granulés comprenant : une étape d'extrusion, à partir d'un orifice de sortie de filière, d'un brin comprenant une composition contenant une résine thermoplastique; une étape de refroidissement, tout en tirant le brin; et une étape de découpe du brin qui a été refroidi pour obtenir des granulés. Dans l'étape de refroidissement du brin, le brin est tiré à 20 à 140 cm/seconde. L'étape de refroidissement du brin comprend une étape consistant à tirer le brin dans de l'eau dans un réservoir d'eau pour refroidir le brin à l'eau. Une longueur L du brin immergé dans l'eau dans le réservoir d'eau satisfait à une formule spécifique (en particulier, formule 1).
PCT/JP2020/021678 2019-06-27 2020-06-02 Procédé de production de granulés WO2020261888A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3991936A4 (fr) * 2019-06-27 2022-08-17 Toyobo Co., Ltd. Méthode de production de pastilles

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022037857A1 (fr) 2020-08-18 2022-02-24 Evonik Operations Gmbh Fabrication de granulés à base de polymères haute température par granulation sous eau avec une température élevée de l'eau pour la production de mousses (rigides) à particules

Citations (6)

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Publication number Priority date Publication date Assignee Title
JPS54116564U (fr) * 1978-02-02 1979-08-15
JPH0747545A (ja) * 1993-08-05 1995-02-21 Mitsubishi Chem Corp 脂肪族ポリアミド系樹脂組成物ペレットの製造方法
JPH0796519A (ja) * 1993-08-05 1995-04-11 Mitsubishi Chem Corp 脂肪族ポリアミド系繊維強化樹脂組成物ペレットの製造方法
JP2000246733A (ja) * 1999-03-04 2000-09-12 Toray Ind Inc ポリアリーレンスルフィド樹脂ペレットの製造方法
JP2003285320A (ja) * 2002-03-27 2003-10-07 Unitika Ltd ポリアリレート樹脂ペレットの製造方法
WO2017111055A1 (fr) * 2015-12-23 2017-06-29 日本合成化学工業株式会社 Pastilles de composition de résine

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS54116564U (fr) * 1978-02-02 1979-08-15
JPH0747545A (ja) * 1993-08-05 1995-02-21 Mitsubishi Chem Corp 脂肪族ポリアミド系樹脂組成物ペレットの製造方法
JPH0796519A (ja) * 1993-08-05 1995-04-11 Mitsubishi Chem Corp 脂肪族ポリアミド系繊維強化樹脂組成物ペレットの製造方法
JP2000246733A (ja) * 1999-03-04 2000-09-12 Toray Ind Inc ポリアリーレンスルフィド樹脂ペレットの製造方法
JP2003285320A (ja) * 2002-03-27 2003-10-07 Unitika Ltd ポリアリレート樹脂ペレットの製造方法
WO2017111055A1 (fr) * 2015-12-23 2017-06-29 日本合成化学工業株式会社 Pastilles de composition de résine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3991936A4 (fr) * 2019-06-27 2022-08-17 Toyobo Co., Ltd. Méthode de production de pastilles

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