JP5638882B2 - Method for extrusion molding of thermoplastic resin composition - Google Patents

Description

  The present invention relates to a method for extruding a thermoplastic resin composition, and particularly relates to a method for extruding a thermoplastic resin composition for extruding a thermoplastic resin composition into a strand shape.

  Conventionally, in granulation (manufacture of pellets) of a resin composition, it has been widely performed to melt a thermoplastic resin composition and extrude it into a strand shape. Usually, in such extrusion molding, a strand-shaped resin is formed by attaching a die having a plurality of nozzle-shaped discharge holes generally to the cylinder tip of the extruder and extruding the molten resin composition from the extruder through the discharge holes of the die. A composition product is produced. When granulating the resin composition, the resin composition product extruded in a strand shape is cut into predetermined lengths by a cutter blade.

  When the resin composition is continuously extruded from the nozzle-like discharge holes, a small part of the extruded resin composition adheres to the edge of the discharge holes. Such a small amount of the resin composition adhering to the edge of the discharge hole is called “eyes”. In the eye, the longer the extrusion duration, the larger the deposit, and the characteristics of the resin composition deteriorate or discolor due to the influence of heat or oxidation.

  If left unattended, it accumulates and grows. At some point, it peels off from the edge of the discharge hole, adheres to the extruded strand resin composition, and is mixed into resin composition products (pellets, etc.) To do. Such an eye is a foreign matter for the resin composition product because its appearance (color, shape) and physical properties are different from a normally granulated resin composition. For example, if large eyes or nails are mixed in the pellet, the appearance and physical properties of a molded product molded from the pellet may be impaired.

  For this reason, proposals have been made to suppress the generation of the eyes and the contamination of the generated eyes (foreign matter) into the product (pellets). For example, Patent Document 1 discloses a process in which gas is blown to the outer periphery (strand surface) of the discharge hole to blow off the eyes or the resin composition attached to the edge of the discharge hole is still small and the deterioration does not proceed ( An extrusion molding machine is disclosed in which it is adhered to the surface of an unsolidified strand-shaped resin composition, dispersed and diluted, and suppresses the mixing and generation of (foreign matter) in the eyes as an independent solid substance.

Japanese Patent No. 3681172 (FIGS. 2 to 6)

  According to the technique described in Patent Document 1, mixing and generation in the eyes can be suppressed to some extent, but their effects are insufficient, and in order to completely eliminate the eyes, the gas blown to the outer periphery of the tip of the discharge hole It was necessary to increase the flow rate. However, since this gas is also blown onto the surface of the strand, the extruded strand may become unstable, and the strand may break or the adjacent strands may be fused, making stable extrusion difficult.

  The present invention has been made in view of such problems of the prior art, and when the thermoplastic resin composition is extruded from a discharge nozzle of a die and extruded into a strand shape, it is effective to deposit on the eyes at the tip of the discharge nozzle. It is an object of the present invention to provide an extrusion molding method that can be suppressed.

  As a result of repeated investigations on the appearance of the eyes and the eyes by airflow, the inventor discharged the die while extruding the resin composition at a specific discharge amount when extruding the thermoplastic resin composition into a strand shape. It has been found that by depositing gas in the vicinity of the nozzle tip, it is possible to effectively suppress deposition on the eyes and at the tip of the discharge nozzle, and the present invention has been achieved.

The above-described object is a method of extruding a thermoplastic resin composition from a discharge nozzle using an extrusion apparatus equipped with a base having a discharge nozzle, wherein the tip portion has a wall thickness Lt of 0 <Lt ≦ 2 mm. While using a nozzle and blowing a gas to the vicinity of the tip of the discharge nozzle, the thermoplastic resin composition is extruded at a discharge rate of 14 kg / hour or more and 40 kg / hour or less per discharge nozzle. In addition, the thermoplastic resin composition is expanded by the ballast effect, the gas flow is changed in the expanded portion, and a portion of the extruded thermoplastic resin composition is prevented from being deposited on the tip of the discharge nozzle , The expansion coefficient due to the ballast effect of the thermoplastic resin composition is such that the inner diameter of the discharge nozzle is φd, and the thermoplastic resin composition is extruded from the discharge nozzle in a strand shape, The diameter of the resin strand after Zhang when as D, by extrusion a thermoplastic resin composition characterized by determining the discharge amount so that 1.35 ≧ D / φd ≧ 1.05 Achieved.

  With such a configuration, according to the present invention, it is possible to effectively suppress deposition on the eyes at the tip of the discharge nozzle.

It is a vertical sectional view showing an example of composition around a die of an extrusion device to which an extrusion molding method according to an embodiment of the present invention can be applied. FIG. 2 is a vertical sectional view for explaining the positional relationship between a discharge nozzle 12 and a gas outlet 11 in FIG. 1 in more detail. (A) is a figure which shows typically the shape example and ballast effect of a discharge nozzle front-end | tip, (b)-(d) shows the other shape example of a discharge nozzle front-end | tip, and the definition of the thickness of a discharge nozzle front-end | tip part. FIG. It is a figure for demonstrating the principle of this invention. It is a figure which shows an example of the structure for making the airflow from the gas outlet 11 turbulent. (A) is a front view of two of the discharge nozzles 12 provided in the resin extrusion die according to the embodiment of the present invention, and (b) is a discharge of the resin extrusion die according to the embodiment of the present invention. The longitudinal cross-sectional view of a nozzle, (c) is a figure for demonstrating the structure of the manifold of the die for resin extrusion which concerns on embodiment of this invention. (A) is the figure which showed typically the structure which concerns on the process until it processes the strand extruded using the resin extrusion die | dye which concerns on embodiment of this invention into a pellet form, (b) conveys a strand. The figure which shows the structural example of a guide roller, (c) is a figure for demonstrating the structure of the groove | channel of the guide roller shown in FIG.7 (b).

Hereinafter, the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a vertical sectional view showing a configuration example around a die of an extrusion apparatus to which an extrusion molding method according to an embodiment of the present invention can be applied.
In the present invention, the configuration of the extrusion apparatus main body excluding the die can adopt a known arbitrary form such as a single-screw extrusion apparatus or a multi-screw extrusion apparatus, so the details of the configuration are not described. Omitted. Moreover, there is no restriction | limiting in particular also about the peripheral apparatus relevant to extrusion apparatuses, such as a hopper and a feeder, According to the resin composition etc., an appropriate type peripheral apparatus can be employ | adopted suitably.

  A resin extrusion die (hereinafter simply referred to as a die) is composed of a die 8 attached to a die holder 5 provided at the tip of a cylinder of an extrusion device, for example, with a screw 21 and a cover 10 attached to the die 8 with, for example, a screw 22. The

  A discharge nozzle 12 having a discharge hole 15 is provided in the base 8, and a molten resin composition supplied to a flow path 9 provided in the die holder 5 by a screw (not shown) of an extrusion device is provided in the discharge hole 15. Extruded into a strand. The O-ring-shaped packing 13 is provided to block the gap between the die holder 5 and the die 8 and prevent the high-pressure molten resin composition from leaking from the attachment portion between the die 8 and the die holder 5.

  Since FIG. 1 is a vertical sectional view, only one discharge nozzle 12 is shown, but a plurality of discharge nozzles 12 may be arranged at predetermined intervals in a direction perpendicular to the paper surface. Further, in the following description, the lower direction of FIG. 1 is vertically downward, and the resin composition is extruded slightly downward from the horizontal direction. However, in the die according to this embodiment, the extrusion direction of the resin composition There is no limitation, and the mounting angle of the die and / or the direction of the discharge nozzle 12 can be arbitrarily changed.

  The cover 10 is attached to the base 8 so as to form a space with the base 8. Further, a gas inlet 14 for introducing gas into the cover 10 from a gas supply unit (not shown) is provided in the upper front portion of the cover 10, and the gas is supplied through a gas supply nozzle 14 a attached to the gas inlet 14. It is introduced into the cover 10 from the supply unit. In this embodiment, air is used as the gas, but the gas is not limited to air, and may be an inert gas, nitrogen gas, or water vapor.

  If the gas can be supplied to the space between the cover 10 and the base 8, it is not necessary to provide the gas inlet 14 in the cover 10. For example, when the gas is supplied through the base 8, the gas inlet 14 may not be provided in the cover 10.

  The cover 10 is also provided with gas outlets 11 corresponding to the individual discharge nozzles 12. The gas outlet 11 is provided for blowing the gas supplied from the gas supply port 14 to the space inside the cover 10 around the vicinity of the tip of the discharge nozzle 12. The inner wall 10 a around the gas outlet 11 of the cover 10 is tapered in a mortar shape toward the gas outlet 11 so as to gradually narrow the gas flow path toward the gas outlet 11. Thereby, the gas can be efficiently blown to the vicinity of the tip of the discharge nozzle 12 along the outer peripheral surface of the discharge nozzle 12. The cover 10 may be configured to cover at least a part of the base 8 so that the gas supplied from the gas supply port 14 can flow out only from the gas outlet 11.

FIG. 2 is a vertical sectional view for explaining the positional relationship between the discharge nozzle 12 and the gas outlet 11 in FIG. 1 in more detail.
The gap d between the gas outlet 11 and the outer periphery of the tip end of the discharge nozzle 12 is substantially uniform, and preferably 1.0 mm ≧ d ≧ 0.1 mm. More preferably, 0.7 ≧ d ≧ 0.2 mm.
When d is less than 0.1 mm, the gas flow rate becomes insufficient, and the eyes and the eyes easily adhere to the tip of the nozzle (or the attached eyes and the eyes easily accumulate). On the other hand, although d may be configured to exceed 1.0 mm, it is significant for the effect of suppressing the generation and deposition of the eyes and the effect of removing the adhered eyes against the increase in the required gas flow rate. It is not realistic because there is no change.

  Further, when the taper angle of the outer periphery of the tip of the discharge nozzle 12 is α and the taper angle around the gas outlet 11 is β, the flow rate is increased by decreasing the cross-sectional area of the gas flow channel toward the gas outlet 11. , Α <β is preferable. Further, β-α is preferably 0.5 ° or more, more preferably 1 ° or more, and most preferably 3 ° or more. Moreover, it is preferable that (beta)-(alpha) is 50 degrees or less. If it exceeds 50 °, the air velocity at the tip of the nozzle is decreased, and the effect of suppressing deposition on the eyes is reduced.

  The inner diameter φd of the discharge nozzle 12 is preferably 7 mm ≧ φd ≧ 2 mm. If it is larger than 7 mm, the strand becomes too thick, and it is easy to cut at the time of take-up, and the productivity is lowered. On the other hand, if it is smaller than 2 mm, the pressure in the die becomes too high and it is easy to vent up.

  Furthermore, in order to suppress the accumulation of eyes and / or eyes on the tip of the discharge nozzle 12 (the edge of the discharge hole 15), the tip of the discharge nozzle 12 is tapered so as to reduce the wall thickness. Lt = (outer diameter φD−inner diameter φd) / 2 is desirably small as long as the strength can be maintained.

  FIG. 3A is a diagram schematically showing an example of the shape of the tip of the discharge nozzle and the ballast effect. If the diameter of the molten resin composition in the discharge nozzle 12 (= the inner diameter of the discharge nozzle 12) is φd, and the diameter of the molten resin composition expanded by being pushed out of the discharge nozzle 12 is D, then D> φd. Such a phenomenon in which the extruded molten resin composition expands is known as a ballast effect (also called a die swell), and is caused by the extruded molten resin composition having viscoelasticity.

  Here, when the thickness Lt of the tip end portion of the discharge nozzle 12 is large, the end surface 12b that is formed at the tip end portion 12a of the discharge nozzle 12 and is substantially perpendicular to the extrusion direction of the resin composition becomes large. The gas flowing out from the gas outlet 11 around the discharge nozzle 12 travels along the outer periphery of the discharge nozzle 12, and then flows into the extruded molten resin composition a1 and the airflow a2 that vortexes behind the end face 12b. However, it is considered that when the end surface 12b becomes large, a region 12c where the spiral airflow a2 does not reach is generated, so that the eyes 12 are easily attached to the region 12c.

  Therefore, in order to reduce the substantially vertical end surface 12b, the thickness Lt of the tip portion 12a of the discharge nozzle 12 is preferably small, and specifically, 0 <thickness Lt ≦ 2 mm. When the wall thickness Lt exceeds 2 mm, it is difficult to sufficiently obtain the effect of blowing the gas to the outer periphery in the vicinity of the tip of the discharge nozzle 12 for the reason described above.

In addition, in order to reduce the end surface 12b substantially perpendicular to the extrusion direction of the resin composition (substantially 0 mm), the shape of the tip portion 12a of the discharge nozzle 12 can be processed. Here, the fact that the end face 12b is substantially 0 mm means that the thickness Lt is about 0.05 mm or less. For example, as shown in FIG. 3B, the surface substantially perpendicular to the extrusion direction of the resin composition is substantially eliminated by processing the outer peripheral surface of the tip 12a into a curved surface (so-called round shape). Can do. Of course, this radius may be a so-called “chamfered” shape that is not a curve. In the case of the shape of FIG. 3 (b), the thickness Lt of the tip end portion 12a is φD in the above-described Lt = (φD−φd) / 2, and in a vertical section along the central axis in the longitudinal direction of the discharge nozzle 12, It can be obtained by using the interval of the intersection point P between the straight line 12f passing through the two most distal points 12e of the tip 12a and the straight line 12d obtained by extending the line formed by the outer peripheral surface.
The wall thickness Lt is preferably as close to 0 as possible, but the deformation or loss of the tip 12a may be a fatal defect. Therefore, when the structure shown in FIG. 3A is adopted, the wall thickness Lt is 0.03 mm. It is considered to be better than the above.

FIG. 3C shows another processing example for reducing the end face 12b substantially perpendicular to the extrusion direction of the resin composition. In FIG. 3C, instead of processing the tip portion 12a into a curved surface, a portion corresponding to the end surface 12b is processed into a curved mortar shape toward the center of the nozzle. In this case, φD that defines the wall thickness Lt can be defined as the distance between the two most distal points 12 g of the tip end portion 12 a in the vertical cross section along the central axis in the longitudinal direction of the discharge nozzle 12. When the end face 12b exists, as shown in FIG. 3D, φD can be defined as the maximum interval between the two most advanced points (interval of 12g ′).
In addition, it is preferable that a round (arrow R) is formed on the inner surface of the nozzle tip, and this round formation promotes smooth expansion (expansion / expansion due to the ballast effect) of the resin composition, and deposits on the eyes. It helps a lot. The size of the radius (the radius defining the radius) is suitably about 0.005 to 1 mm. In the case of so-called chamfering in which the rounded surface is a flat surface, a surface width of about 0.005 to 1 mm is appropriate.

  In the present invention, gas is supplied so that the linear velocity of the airflow flowing out from each gas outlet 11 is 4 to 100 m / sec. When the linear velocity is less than 4 m / sec, the wind pressure becomes insufficient, and the effect of suppressing the deposition on the eyes cannot be obtained sufficiently. Moreover, when it exceeds 100 m / second, the influence with respect to the extruded resin composition, such as a resin composition strand being cut | disconnected by a wind pressure, may arise.

  Further, the temperature of the gas varies depending on the type of the resin composition to be extruded, the softening point, the melting temperature, and the like, but from (Tg (glass transition temperature) -100) ° C. to (Tg + 150) ° C. for an amorphous resin composition. It is preferable to be heated to this temperature. For example, when polycarbonate is used as the resin, the temperature is preferably about 50 ° C to 300 ° C. In the case of a crystalline resin, it is preferably heated to (Tm (melting temperature) −150) ° C. to Tm + 50 ° C. For example, when polybutylene terephthalate is used as the resin, the temperature is preferably about 70 to 270 ° C. Furthermore, it is more preferable that the amorphous resin is heated to a temperature of (Tg−70) ° C. to (Tg + 130) ° C., and that of the crystalline resin is (Tm−120) ° C. to Tm + 20 ° C. By setting such temperature, it can be removed by blowing without solidifying the eyes and there is no fear of adverse effects such as lowering the die temperature. A higher temperature gas can be used, but a better effect cannot be expected. Rather, if the temperature of the gas is too high, the discoloration of the eyes slightly occurring near the nozzle is promoted.

(Thermoplastic resin and thermoplastic resin composition)
The components of the thermoplastic resin composition extruded into a strand shape by the extrusion molding method of the present invention are not particularly limited. However, according to JIS K7199, the shear viscosity measured at a temperature of 280 ° C. and a shear rate of 100 / sec is 50 Pa. It is preferably at least 2 seconds and at most 5000 Pa · seconds. More preferably, the shear viscosity measured under the same conditions is 80 Pa · sec or more and 3000 Pa · sec or less.
When the shear viscosity is less than 50 Pa · sec, the viscosity is low and the ballast effect is reduced, and therefore, the effect of suppressing deposition on the eyes cannot be sufficiently obtained even by controlling the discharge amount described later. On the other hand, when the shear viscosity exceeds 5000 Pa · sec, heat is easily generated, the resin is thermally decomposed and foamed, and the strands are easily cut. Moreover, the generation | occurrence | production to eyes and eyes also increases by thermal decomposition.

  It is also possible to perform molding as shown in Fig. 4 (a) by selecting a resin (composition) with a large ballast effect or changing molding conditions (for example, slowing the take-up speed). It is. In this molding, the ballast effect is made extreme by rubbing the substantially vertical end surface 12b of the nozzle tip 12a with the surface of the strand, and immediately adheres to the surface of the strand and moves before it is deteriorated. In addition, accumulation on the eyes and on the nozzle tip 12a is suppressed.

  The thermoplastic resin constituting the thermoplastic resin composition may be a single component of a thermoplastic resin such as polycarbonate, polybutylene terephthalate, polyamide, polyphenylene ether, polyacetal, or a mixture of a plurality of thermoplastic resins. A reinforcing filler can be blended in the molten resin. Non-limiting examples of reinforcing fillers include glass fibers, carbon fibers, silica / alumina fibers, zirconia fibers, boron fibers, boron nitride fibers, silicon nitride potassium titanate fibers, metal fibers and other inorganic fibers, aromatics Examples thereof include organic fibers such as polyamide fibers and fluororesin fibers. These reinforcing fillers can be used in combination of two or more.

  Together with or separately from the reinforcing filler, other fillers can be blended into the molten resin. Non-limiting examples of other fillers include plate-like inorganic fillers, ceramic beads, asbestos, wollastonite, talc, clay, mica, zeolite, kaolin, potassium titanate, barium sulfate, titanium oxide, silicon oxide , Aluminum oxide, magnesium hydroxide and the like. Among these, the anisotropy and warpage of the molded product can be reduced by blending the plate-like inorganic filler. Non-limiting examples of the plate-like inorganic filler include glass flakes, mica, metal foil and the like. Among these, glass flakes are preferably used.

  Further, phenol compounds such as 2,6-di-t-butyl-4-octylphenol, pentaerythrityl-tetrakis [3- (3 ′, 5′-t-butyl-4′-hydroxyphenyl) propionate], dilauryl- Thioether compounds such as 3,3′-thiodipropionate, pentaerythrityl-tetrakis (3-laurylthiodipropionate), triphenyl phosphite, tris (nonylphenyl) phosphite, tris (2,4-di- Antioxidants such as phosphorus compounds such as t-butylphenyl) phosphite, paraffin wax, microcrystalline wax, polyethylene wax, long-chain fatty acids such as montanic acid and montanic acid esters and their release, release of silicone oil, etc. An agent or the like may be added to the molten resin.

  Moreover, a flame retardant can be blended in order to impart flame retardancy to the resin. Non-limiting examples of flame retardants include organic halogen compounds, antimony compounds, phosphorus compounds, other organic flame retardants, inorganic flame retardants, and the like. Among these, examples of the organic halogen compound include brominated polycarbonate, brominated epoxy resin, brominated phenoxy resin, brominated polyphenylene ether resin, brominated polystyrene resin, brominated bisphenol A, pentabromobenzyl polyacrylate and the like. . Examples of the antimony compound include antimony trioxide, antimony pentoxide, sodium antimonate, and the like. As a phosphorus compound, phosphate ester, polyphosphoric acid, ammonium polyphosphate, red phosphorus etc. are mentioned, for example. Examples of other organic flame retardants include nitrogen compounds such as melamine and cyanuric acid. Examples of other inorganic flame retardants include aluminum hydroxide, magnesium hydroxide, silicon compound, and boron compound.

  Also, if necessary, thermoplastic resins such as polyethylene, polypropylene, polystyrene, polyacrylonitrile, polymethacrylic acid ester, ABS resin, polycarbonate, polyamide, polyphenylene sulfide, polyethylene terephthalate, liquid crystal polyester, phenol resin, melamine resin, silicone Thermosetting resins such as resins and epoxy resins can be blended. These thermoplastic resins and thermosetting resins can also be used in combination of two or more.

Thus, the extrusion molding method of the present invention can be applied to the extrusion of various thermoplastic resin compositions. However, it goes without saying that it is particularly effective to apply to thermoplastic resins (including a single component and a resin composition) that are easily generated in the eyes.
If the thermoplastic resin is a single component, there is little occurrence in the eyes. For example, when only a thermoplastic resin such as polycarbonate, polybutylene terephthalate, polyamide, polyphenylene ether, or polyacetal is extruded as a single component, there is little occurrence in the eyes.

  However, when other components such as the above-described reinforcing filler, filler, flame retardant, other thermoplastic resin, and thermosetting resin are added to these thermoplastic resins, the appearance of the eyes becomes conspicuous. When these other components are contained in the molten resin in an amount of 5% or more, the generation of the eyes is increased, and when the content is 10% or more, the generation of the eyes becomes remarkable. Therefore, by using the extrusion molding method of the present invention for the extrusion of a resin composition containing 5% or more of other components, it is possible to enjoy a remarkable effect of suppressing deposition on the eyes and mixing into the molded product.

(Effect of release agent)
Examples of the thermoplastic resin extruded in the form of a strand using the extrusion method of the present invention include paraffin wax, microcrystalline wax, polyethylene wax, long chain fatty acids represented by montanic acid and montanic acid ester, esters thereof, silicone oil, and the like. By adding a release agent, it is possible to further reduce the occurrence of eye spots. This is because the release agent added to the thermoplastic resin functions as a lubricant between the surface of the nozzle and the molten resin at the outlet of the discharge hole, making it difficult for the molten resin to adhere to the nozzle (deposition on the eyes is suppressed to some extent) Is). When added in an amount of 0.03% or more to the thermoplastic resin (composition) for extruding the release agent, an effect of suppressing deposition on the eyes appears, and particularly when added in an amount of 0.1% or more, the effect becomes remarkable. On the other hand, even if it is added at a ratio exceeding 1%, the improvement in the effect is small.

(Discharge rate)
In the extrusion molding method of the present invention, the increase in diameter (die swell ratio) due to the ballast effect is controlled by controlling the discharge amount of the molten resin (composition), and along the outer periphery of the discharge nozzle 12 from the gas outlet 11. The direction of the air flow is changed by allowing the air flow to be blown to the expanded part of the strand, so that the gas hits the part where the molten resin composition separates from the discharge nozzle (the part where the eyes are easily formed) with sufficient wind pressure. It is characterized by suppressing deposition on the eyes. It should be noted that the effect of suppressing the deposition on the eyes is achieved not only by suppressing the generation of the eyes itself, but also by blowing off the generated eyes and eyes in a minute stage.

  Here, the expanded portion of the strand is, as shown in FIG. 4A, from the time (diameter = inner diameter φd of the discharge nozzle 12) when the molten resin (composition) is pushed out from the discharge hole of the discharge nozzle 12. , The section 41 until the diameter D becomes substantially constant. In other words, it means a portion where the diameter of the molten resin continues to increase due to the ballast effect.

  According to the inventors' investigation, the lower limit of the discharge amount of the molten resin (composition) from the discharge nozzle is 14 kg / hour or more, preferably 17 kg / hour or more, more preferably 19 kg / hour or more, and the upper limit is 40 kg / hour. When the amount is less than 30 hours, preferably 30 kg / hour or less, more preferably 24 kg / hour or less, the above-described thermoplastic resin (composition) having the shear viscosity can have a good ballast effect, and it can be easily observed. It has been found that it is possible to prevent contamination.

  As shown in FIGS. 4 (a) and 4 (b), the expanded portion of the resin strand has an existence like a wall as viewed from the air flow a, particularly the component flowing from the gas outlet 11 along the outer peripheral surface of the discharge nozzle 12. Become. Therefore, the airflow hits the expansion portion and changes its direction, and the gas pressure acts on the portion where the strands are separated from the discharge nozzle 12 and in the vicinity thereof, that is, the portion where the eye easily occurs. It is considered that the deposition suppressing effect is effectively realized.

When the discharge amount is less than 14 kg / hour or exceeds 40 kg / hour, the effect of preventing the eyes and the eyes from being mixed into the resin product cannot be sufficiently obtained.
In addition, when the discharge nozzle 12 is provided with two or more in the nozzle | cap | die 8, the discharge amount here is a discharge amount per discharge nozzle.

In particular, the expansion rate of the diameter due to the ballast effect (die swell ratio) = D / φd is preferably 1.05 or more, and more preferably the discharge amount is determined to be 1.1 or more. The die swell ratio is preferably 1.35 or less. When the die swell ratio exceeds 1.35, the eyes and the eyes are liable to occur. This is presumably because the flow of the air flow changes when the die swell ratio exceeds 1.35, and it is difficult for the gas pressure to act on the area where the eyes swell. The die swell ratio is more preferably 1.30 or less.
The die swell ratio is determined by taking a photograph of the strand of the resin composition being molded and the tip of the nozzle (inner diameter) in the unmolded state from the same position. ) Was actually measured from the photograph, and the ratio of diameter (φD / φd) was defined as the die swell ratio.

(Airflow turbulence)
It should be noted that the effect of the present invention can be further enhanced by changing at least one of the flow velocity and the direction of the air flow blown along the outer periphery of the discharge nozzle 12 with time (turbulence). This can be realized by changing the gas supply amount with time, but can also be realized by vibrating the gas outlet 11 and the discharge nozzle 12.

FIG. 5 is a diagram illustrating an example of a configuration in which the airflow is turbulent by vibrating the gas outlet 11 and the tip of the discharge nozzle 12.
In the configuration shown in FIG. 5, a vibration generator 30 that vibrates the base 8 is provided. The vibration generator 30 has a vibration member (not shown) such as an actuator, and the operation of the actuator is controlled by a control circuit (not shown). In the operating state, the vibration generator 30 can vibrate the base 8 (and the cover 10 attached to the base 8) in a vertical direction or a horizontal direction at a predetermined frequency and amplitude.

  Thereby, turbulence can be produced in the flow of the gas flowing out from the gas outlet 11 and the turbulent flow can be stably formed. Here, the vibration applied to the base 8 preferably has an amplitude of 0.005 mm to 0.2 mm and a vibration speed of 0.3 mm / second to 5 mm / second. The vibration frequency (Hz) can be obtained by vibration speed (mm / s) / (2π × amplitude (mm)). Exceeding the upper limit of the amplitude and vibration speed may cause the extruded strands to vibrate greatly, and the strands extruded from the adjacent discharge holes may collide or the contact between the strands and the cooling water may become unstable. Can not be manufactured. In addition, the screws 21 and 22 for fixing the base 8 and the cover 10 may be loosened, which may cause a stable production. On the other hand, if it is less than the lower limit, the effect of turbulent airflow due to vibration cannot be obtained sufficiently.

  Vibrating the base 8 with a predetermined amplitude and vibration speed is often an important requirement in terms of eye removal effects. That is, when the base 8 vibrates, the eyes and corners are more likely to come off (easy to fly) from the tip of the discharge nozzle 12 at an earlier stage (easy to fly) than when the base 8 does not vibrate, and the extruded strand also vibrates. This is because a synergistic effect is achieved in that the eye or the eye that is blown off by the airflow or vibration is less likely to adhere to the surface of the strand.

  Note that the configuration shown in FIG. 5 is an example of a configuration for turbulent airflow flowing out from the gas outlet 11, and it goes without saying that other configurations can be adopted. For example, the base 8 (and the cover 10) is vibrated using vibration generated by a driving device (motor, etc.) of the extrusion device without providing an active vibration member such as the vibration generator 30. May be.

(More details about the configuration of the discharge nozzle)
In addition, when shape | molding a molten resin composition in strand form using the resin extrusion die | dye which has the above-mentioned structure, although the several discharge nozzle 12 is provided in die | dye, by making this discharge nozzle into a specific structure, The inventors have clarified that the extrusion is stable and effective in preventing (removing) the eyes and preventing the strands from being cut.

Here, the specific structure is
(1) In order to equalize the inner diameter φd (cross-sectional area perpendicular to the extrusion direction) of the plurality of discharge nozzles and the pressure of the molten resin composition supplied to the plurality of discharge nozzles, The relationship with the cross-sectional area of the manifold 120 provided on the side) (cross-sectional area perpendicular to the extrusion direction) satisfies a specific relationship, and
(2) The length of the discharge nozzle satisfies a specific condition,
Structure.

6A is a front view of two of a plurality of discharge nozzles 12, and FIG. 6B is a longitudinal sectional view of a discharge nozzle 12 (including an axis when the discharge nozzle is regarded as a cylindrical shape). It is a vertical sectional view). When the die includes a plurality of discharge nozzles 12, a manifold 120 for supplying a molten resin composition with a uniform pressure to the plurality of discharge nozzles 12 is usually provided at the rear of the plurality of discharge nozzles 12. . The molten resin composition is supplied to all the discharge nozzles 12 through a common manifold 120. The molten resin composition supplied to the die from the extruder once stays in the manifold 120, the pressure is made uniform, and the extrusion amount from the discharge nozzle 12 becomes uniform by being squeezed by the thin discharge nozzle 12. At this time, if the narrowing rate at the discharge nozzle 12 is too small (if it is not narrowed too much), the pressure applied to each discharge nozzle 12 becomes uneven, the strands are not stable, the strands break, and the eyes on the discharge nozzles 12 adhere to the eyes. Become more. If the squeezing rate is too large, the resin pressure becomes high, the resin filling region at the screw tip of the extruder becomes long, heat is generated by shearing, the resin temperature rises, and there is a lot of generation in the eyes. If the discharge nozzles 12 are too short, the pressure applied to the discharge nozzles 12 is not uniform, the strands are not stable, the strands break, and the eyes and the adherence to the discharge nozzles 12 increase. Similarly, if the length is too long, the resin temperature rises and the generation of the eyes increases.
Therefore, the balance between the narrowing rate and the length of the discharge nozzle 12 has a great influence on the stability of the strands and, in turn, on the eyes.

  The narrowing ratio from the manifold 120 to the discharge nozzle 12 is determined by the total area S1 of the minimum cross-sectional area of the discharge nozzle 12 and the maximum cross-sectional area S2 of the manifold 120 (represented by the diameter of the manifold 120 × the length of the manifold 120) It can be expressed as the ratio of the cross-sectional area orthogonal to the maximum), that is, the nozzle aperture ratio = S1 / S2.

Although a slight change occurs depending on the shape of the manifold 120, the diameter of the manifold 120 is the diameter shown in FIG. 6B, that is, the maximum projected vertical distance when the discharge nozzle 12 is viewed from the front. The 120 length is a distance in the longitudinal direction including the length as shown in FIG. In FIG. 6C, only the manifold 120 and the discharge nozzle are extracted and schematically shown so that the shape of the manifold 120, which is a cavity formed in the die, can be seen.
The nozzle opening ratio that is the ratio S1 / S2 of the total area S1 of the minimum cross-sectional area of the discharge nozzle 12 and the maximum area S2 of the manifold 120 defined in this way is 10% ≧ S1 / S2 ≧ 1.2%. It is more preferable that 8% ≧ S1 / S2 ≧ 2%. In addition, if the nozzle opening ratio is large, unevenness in the resin pressure applied to each nozzle occurs, and the flow of the resin composition from each nozzle becomes non-uniform. As a result, the occurrence of eyes and eyes increases. Moreover, if the opening ratio is small, the residence time of the resin composition in the manifold becomes long, and the heat history is received, so that the eyes are liable to occur.
Moreover, the length of the discharge nozzle 12 is 15-50 mm, More preferably, it is 18 mm-40 mm. When the discharge nozzle is shortened, the rate of increase in the strand diameter (die swell ratio) due to the so-called ballast effect increases, and the eyes and the eye easily adhere to the tip of the discharge nozzle. On the contrary, when the discharge nozzle becomes longer, the resin staying area at the screw tip becomes longer and the resin temperature rises, so that the eyes are easily generated.
By keeping the nozzle aperture ratio S1 / S2 and the length of the discharge nozzle 12 in such a balance, the strands can be stably extruded, which leads to the effect of suppressing the occurrence of eyes.

  The discharge nozzle 12 generally has a structure having a cross section as shown in FIG. 6B. The inner diameter of the discharge nozzle 12 refers to the smallest diameter portion at the tip of the discharge nozzle 12, and has a larger shape. It is not the diameter of the root portion (manifold 120 side) having However, the length of the discharge nozzle 12 is not the length of only the minimum diameter portion but the length of the entire portion protruding from the manifold 120.

FIG. 7A is a diagram schematically illustrating a configuration related to a process until the strand extruded from the discharge nozzle 12 is processed into a pellet shape.
The strand 91 is taken up by the take-up roller 95 and processed (cut) into a pellet form by the pelletizer 96, but is usually cooled in the transport path before being supplied to the pelletizer 96. Specifically, as shown in FIG. 7A, the cooling medium (usually water) 93 stored in the cooling tank 92 is conveyed and cooled. In order to reduce the deterioration of the resin composition, it is better that the time from when the strand 91 is pushed out from the discharge nozzle 12 until it enters the cooling medium 93 is shorter. Normally, it is preferable to enter the cooling medium 93 within one second after being pushed out from the discharge nozzle 12.

Therefore, it is preferable to transport the discharge nozzle 12 so as to be directed to the cooling medium 93 at a shortest distance, and it is preferable to transport the cooling medium 93 so that the time for cooling is long.
In order to realize a transport path that satisfies such conditions, guide rollers such as 94A and 94B are generally provided in the transport path of the strand 91. The diameter of the guide rollers 94A and 94B is usually about 3 to 7 cm.

According to the study of the present inventor, by using at least one of such a conventionally used transport mechanism, specifically, the guide rollers 94A and 94B, the various methods described above are passed through the strand 91. It has been found that it is possible to further reduce the number of eyes attached to the surface.
Specifically, at least one of the guide rollers 94A and 94B is rotated in the direction opposite to the traveling (conveying) direction of the strand 91, or at a peripheral speed slower than the traveling speed (take-off speed) of the strand 91. Is rotated in the same direction as the traveling direction (or may be held without being rotated).

The guide rollers 94A and 94B usually have a cylindrical shape having a rotation axis in a direction crossing the running direction of the strand. The plurality of strands 91 are supported on the cylindrical surface (outer peripheral surface) so that the strands 91 that are extruded in parallel are transported along a desired transport path.
As shown in FIG. 7B, a plurality of annular (ring-shaped) grooves 942 are provided on the cylindrical surfaces of the guide rollers 94A and 94B in the circumferential direction. The groove 942 receives and supports the traveling strand 91, and prevents the strands 91 located in close proximity from coming into contact with each other and fused.

  The width of the groove 942 is slightly wider than the thickness of the strand 91, and the bottom of the groove 942 is preferably arcuate for stable support. Further, the depth of the normal groove 942 is 2 mm to 10 mm although it depends on the diameter of the strand 91. Furthermore, the pitch of the grooves 942 (the interval between adjacent grooves 942) is usually matched to the interval between the strands 91 (the interval between the discharge nozzles 12 of the die). Depending on the diameter of the strand 91, the pitch is 5 mm to 20 mm. The number of grooves 942 may be more than the number of strands to be extruded.

  One or a plurality of guide rollers 94 </ b> A and 94 </ b> B are provided at the strand travel position of the cooling tank 92. In the case of a plurality of pieces, a strand is stretched between the guide rollers 94A and 94B, travels through the cooling tank 92, and is cooled.

  The guide rollers 94A and 94B may be supported so as to be rotatable in the direction opposite to the running direction of the strand or in the same direction as the running direction, or may be supported so as not to rotate. By supporting (or driving) the guide rollers 94A and 94B such that the movement (rotation) speed of the grooves 942 of the guide rollers 94A and 94B becomes relatively slower than the traveling (conveying) speed of the strand 91, the grooves 942 are supported. The surface of the strand 91 can be rubbed with the surface in contact with the strand 91 to remove the eye and the eye attached to the surface of the strand 91. In addition, when the guide roller 94 is provided in the multiple places of a conveyance path | route, what is necessary is just to rub the surface of the strand 91 by supporting or driving at least one as mentioned above.

  In order to rotate the guide rollers 94A and 94B in the direction opposite to the running direction of the strands, a driving device may be provided in the guide rollers 94A and 94B. In this case, if the resistance (friction) between the strand 91 and the surface of the groove 942 (the surface in contact with the strand 91) is too large, the running of the strand 91 may become unstable. Determine the rotation speed (rotation amount per fixed time).

  When the guide rollers 94A and 94B are rotated in the same direction as the traveling direction, the driving device may not be provided. It is only necessary to give a certain amount of resistance to rotate the guide rollers 94A and 94B (at least resistance that prevents the strand 91 from rotating at the speed due to the frictional force of the traveling strand 91). As a result, the guide rollers 94A and 94B rotate following the travel of the strand 91. However, due to the applied resistance, the guide rollers 94A and 94B rotate slower than the travel speed of the strand 91 (peripheral speed is slow). It becomes possible to rub. Although it is possible to provide a drive device, unlike the case of reverse rotation, a configuration that provides resistance to rotation is simpler.

  In this way, the strand 91 contacts the surfaces of the guide rollers 94A and 94B while traveling in the cooling medium 92, and the strand 91 is caused by the difference between the traveling speed of the strand 91 and the rotation speed (circumferential speed) of the guide rollers 94A and 94B. The surface of the groove 942 is rubbed with the surface of the groove 942, and the eye and the eye attached to the surface of the strand 91 are removed.

  This effect cannot be obtained when the guide rollers 94A and 94B are rotated at the same peripheral speed as the traveling speed of the strand 91. When the traveling speed of the strand 91 and the circumferential speed of the guide rollers 94A and 94B are substantially the same speed, not only the surface of the strand 91 cannot be rubbed but also the eyes or the eyes are attached to the strand by the surface of the groove 942. It is also possible that it will be embedded. The specific rotation (circumferential) speed Vr of the guide rollers 94A and 94B is preferably in a relation of 0.7 ≧ Vr / Vs ≧ −0.2 with respect to the strand speed Vs. The upper limit is more preferably 0.5 ≧ Vr / Vs, and the lower limit is more preferably Vr / Vs ≧ 0. Vs can be the take-up speed of the strand 91, and Vr can be obtained by (radius of guide rollers 94A, 94B-groove depth) × 2π × number of rotations per minute. When Vr / Vs is positive, the guide rollers 94A and 94B rotate in the same direction as the strand travel direction. When negative, the guide rollers 94A and 94B rotate in the direction opposite to the strand travel direction.

  One or a plurality of guide rollers 94A and 94B are provided in the cooling tank. In the case of a plurality of guide rollers 94A and 94B, it is not necessary to rotate all of the guide rollers 94A and 94B as described above, and the guide rollers 94A and 94B are in the cooling medium 93. It is effective to remove the guide roller (94A in FIG. 7A) closest to the discharge nozzle 12 (die) as described above.

  Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

<Example 1>
Resin extrusion die as shown in FIGS. 1-2 was produced using die steel SKD11. Three discharge nozzles 12 and three gas outlets 11 were provided at equal intervals in the direction of resin extrusion in the direction perpendicular to the paper surface of FIGS. The gas outlet 11 is circular with a diameter of 5.3 mm, and d = 0.5 mm, φd = 3 mm, φD = 3.2 mm in FIG. 2 (that is, the wall thickness Lt = 0.1 mm of the tip 12 a of the discharge nozzle 12). ), Α = 25 °, β = 35 °, and H = 1 mm.

Toshiba TEM37BS was used for the extruder, and the conditions were a discharge rate of 60 kg / hour (that is, a discharge rate of 20 kg / hour per discharge nozzle) and a screw rotation speed of 500 rpm. As a thermoplastic resin composition, a resin composition (resin composition) containing 30% by weight of talc (TALKAN PAWDER PK-C manufactured by Hayashi Kasei Co., Ltd.) and 70% by weight of polycarbonate (Iupilon S3000 manufactured by Mitsubishi Engineering Plastics) A).
Extrusion was performed at a preset temperature of 250 ° C. of the extruder cylinder and resin extrusion die. The resin temperature is usually considered to be about 30 ° C. higher than the set temperature of the die.
The shear viscosity of the resin composition A was measured by CAPIROGRAPH-1C manufactured by TOYOSEIKI Co., Ltd. according to JIS-K7911 under the conditions of a temperature of 280 ° C. and a shear rate of 100 / sec. .

Moreover, the air heated to 150 degreeC was supplied from the gas supply port 14 so that the flow volume from each gas outflow port might be 10 liter / min in conversion of room temperature. The extruded strand of resin was photographed with a photograph, and the maximum diameter φD measured within 2 cm from the tip of the discharge nozzle for the strand extruded from the die was 3.66 mm. Since the inner diameter φd of the discharge nozzle is 3 mm, the diameter increase rate (die swell ratio) φD / φd = 1.22 due to the ballast effect. (In addition, since the expansion of the resin strand ends within 2 cm after being extruded, the maximum diameter within 2 cm from the tip of the discharge nozzle was measured.)
In addition, a small electrodynamic vibration test device (Wave Maker 01 manufactured by Asahi Seisakusho Co., Ltd.) is attached to the die portion of the resin extrusion die as the vibration generator 30 shown in FIG. 5, and a vibration of 20 Hz is applied in the vertical direction. Except that, the resin composition A was extruded under the same conditions as in Example 1. A pocketable vibrometer VM-63A “RIOVIBRO” manufactured by RION Co., Ltd. was pressed against the base, and the amount of vibration and vibration speed of the base were measured. The amplitude was 0.01 mm and the vibration speed was 1.0 mm / second.
Extrusion was performed continuously for 3 hours, but generation of eyes and contamination with foreign matter (modified resin composition A) were not detected.

<Example 2>
The thermoplastic resin composition was changed to a resin composition B composed of 30% by weight of talc (TALKAN PAWDER PK-C manufactured by Hayashi Kasei Co., Ltd.) and 70% by weight of polybutylene terephthalate (Novalex 5008 manufactured by Mitsubishi Engineering Plastics). Was extrusion molded under the same conditions as in Example 1. The die swell ratio was 1.13, and the shear viscosity of the resin composition B was 130 Pa · sec under the conditions of a temperature of 280 ° C. and a shear rate of 100 / sec.
In the continuous molding for 3 hours, minute eyes and eyes were observed after 2 hours from the start, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but foreign matter (modified resin composition B) was detected in the molded product (in this case, pellets). Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected, and the weight was 1 mg.

<Example 3>
Extrusion molding was performed under the same conditions as in Example 1 except that the discharge rate was 45 kg / hour (15 kg / hour per nozzle). The die swell rate was 1.20.
In the continuous molding for 3 hours, minute eyes and eyes were observed after 2 hours from the start, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but contamination of foreign matter (modified resin composition A) in the molded product (in this case, pellets) was detected. Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected, and the weight was 1 mg.

<Example 4>
Extrusion molding was performed under the same conditions as in Example 1 except that the linear velocity of the air flow was 3 m / sec. The die swell rate was 1.22.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but contamination of foreign matter (modified resin composition A) in the molded product (in this case, pellets) was detected. Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected, and the weight was 4 mg.

<Example 5>
Extrusion molding was performed under the same conditions as in Example 1 except that the gap d between the gas outlet 11 and the outer peripheral surface of the discharge nozzle 12 was 1.1 mm and the linear velocity of the air flow was 10 m / sec. The die swell rate was 1.22.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but contamination of foreign matter (modified resin composition A) in the molded product (in this case, pellets) was detected. Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected, and the weight was 6 mg.

<Example 6>
As resin compositions, 35% by weight of first polybutylene terephthalate (Mitsubishi Engineering Plastics Novalex 5008), second polybutylene terephthalate (Mitsubishi Engineering Plastics Novalex 5007) 35% by weight, talc (Hayashi Kasei) Extrusion was carried out under the same conditions as in Example 1 except that the resin composition C consisting of 30% by weight manufactured by TALKAN PAWDER PK-C) was used. The die swell ratio was 1.04, and the shear viscosity of the resin composition C was 80 Pa · sec under the conditions of a temperature of 280 ° C. and a shear rate of 100 / sec.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but contamination of foreign matter (modified resin composition C) in the molded product (in this case, pellets) was detected. Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected and the weight was measured to be 5 mg.

<Example 7>
The resin composition D was composed of 70% by weight of polybutylene terephthalate (Mitsubishi Engineering Plastics Novalex 5007) and 30% by weight of talc (TALKAN PAWDER PK-C manufactured by Hayashi Kasei Co., Ltd.) as the resin composition. Extrusion molding was performed under the same conditions as in Example 1. The die swell ratio was 1.03, and the shear viscosity of the resin composition D was 40 Pa · sec under the conditions of a temperature of 280 ° C. and a shear rate of 100 / sec.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but contamination of foreign matter (modified resin composition D) in the molded product (in this case, pellets) was detected. Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye or eye attached to the tip of the three discharge nozzles was collected and the weight was measured to be 8 mg.

<Example 8>
The experiment was performed in the same manner as in Example 1 except that the inner diameter φd of the protruding nozzle was 8 mm. The die swell rate was 1.17.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but contamination of foreign matter (modified resin composition A) in the molded product (in this case, pellets) was detected. Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye adhering to the tips of the three discharge nozzles was collected, and the weight was 9 mg.

<Example 9>
An experiment was conducted in the same manner as in Example 1 except that no vibration generator was used.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but contamination of foreign matter (modified resin composition A) in the molded product (in this case, pellets) was detected. Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected, and the weight was measured to be 7 mg.

<Example 10>
As a thermoplastic resin composition, a resin composition (resin composition) containing 30% by weight of talc (TALKAN PAWDER PK-C manufactured by Hayashi Kasei Co., Ltd.) and 70% by weight of polycarbonate (Iupilon E2000 manufactured by Mitsubishi Engineering Plastics Co., Ltd.) Experiments were conducted in the same manner as in Example 1 except that E was used.
The shear viscosity of the resin composition E was measured by CAPIROGRAPH-1C manufactured by TOYOSEIKI Co., Ltd. according to JIS-K7911 under the conditions of a temperature of 280 ° C. and a shear rate of 100 / sec. . The die swell rate was 1.27.
In the continuous molding for 3 hours, minute eyes and eyes were observed after 2 hours from the start, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes and eyes seemed to be attached to the surface of the extruded strands, foreign matter (modified resin composition E) was detected in the molded product (in this case, pellets). Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected and the weight was measured to be 3 mg.

<Example 11>
As a thermoplastic resin composition, a resin composition (resin composition) containing 60% by weight of talc (TALKAN PAWDER PK-C manufactured by Hayashi Kasei Co., Ltd.) and 40% by weight of polycarbonate (Iupilon E2000 manufactured by Mitsubishi Engineering Plastics) Experiments were conducted in the same manner as in Example 1 except that F was used.
The shear viscosity of the resin composition E was measured by a method in accordance with JIS-K7911 using CAPIROGRAPH-1C manufactured by TOYOSEIKI Co., Ltd. under the conditions of a temperature of 280 ° C. and a shear rate of 100 / sec. . The die swell rate was 1.33.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but foreign matter (modified resin composition F) in the molded product (in this case, pellets) was detected. Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye adhering to the tips of the three discharge nozzles was collected, and the weight was 9 mg. Further, during the extrusion, four strand breaks, which are thought to be caused by strand foaming, occurred four times.

<Example 12>
Extrusion molding was performed under the same conditions as in Example 1 except that the discharge amount of the resin composition A was 84 kg / hour (28 kg / hour per nozzle). The die swell rate was 1.25.
In the continuous molding for 3 hours, minute eyes and eyes were observed after 2 hours from the start, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but contamination of foreign matter (modified resin composition A) in the molded product (in this case, pellets) was detected. Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected, and the weight was 1 mg.

<Example 13>
Extrusion molding was performed under the same conditions as in Example 1 except that the discharge amount of the resin composition A was 105 kg / hour (35 kg / hour per nozzle). The die swell rate was 1.26.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but contamination of foreign matter (modified resin composition A) in the molded product (in this case, pellets) was detected. Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected, and the weight was 4 mg.

<Example 14>
Extrusion molding was performed under the same conditions as in Example 1 except that the thickness Lt = (φD−φd) / 2 of the discharge nozzle tip was 0.7 mm.
In the continuous molding for 3 hours, minute eyes and eyes were observed after 2 hours from the start, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but contamination of foreign matter (modified resin composition A) in the molded product (in this case, pellets) was detected. Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected and the weight was measured to be 3 mg.

<Example 15>
Extrusion molding was performed under the same conditions as in Example 1 except that the thickness Lt = (φD−φd) / 2 of the discharge nozzle tip was 1.5 mm.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, but contamination of foreign matter (modified resin composition A) in the molded product (in this case, pellets) was detected. Was not. The deterioration was not progressing, and it was considered to have been diffused and absorbed on the surface of the strand because it was a minute eye. In addition, after 3 hours, a slight eye or eye attached to the tip of the three discharge nozzles was collected and the weight was measured to be 8 mg.

<Example 16>
The tip of the nozzle having the same structure as used above is replaced with a nozzle (inner radius is 0.01 mm) processed so that the wall thickness Lt is substantially 0 as shown in FIG. When molding was carried out in the same manner as described above, even after 4 hours had passed, there was almost no occurrence of eyes and no foreign matter (modified resin composition A) was detected in the molded product.

<Comparative Example 1>
Extrusion molding was performed under the same conditions as in Example 1 except that the thickness Lt = (φD−φd) / 2 of the discharge nozzle tip was 2.1 mm.
Within 3 hours of continuous molding, eyes were observed within 1 hour from the start of molding. Further, after 3 hours, a slight eye adhered to the tip of the three discharge nozzles was collected and the weight was measured to be 32 mg. It was also confirmed that foreign matter (modified resin composition A) was mixed in the molded product (in this case, pellets).

<Comparative example 2>
Extrusion molding was performed under the same conditions as in Example 1 except that the discharge amount of the resin composition A was 30 kg / hour (10 kg / hour per nozzle). The die swell rate was 1.09.
Within 3 hours of continuous molding, eyes were observed within 1 hour from the start of molding. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected and the weight was measured to be 17 mg. It was also confirmed that foreign matter (modified resin composition A) was mixed in the molded product (in this case, pellets).

<Comparative Example 3>
All the experiments were performed in the same manner as in Comparative Example 2 except that the vibration generator was not used.
Within 3 hours of continuous molding, eyes were observed within 1 hour from the start of molding. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected and the weight was measured to be 22 mg. It was also confirmed that foreign matter (modified resin composition A) was mixed in the molded product (in this case, pellets).

<Comparative example 4>
The experiment was performed in the same manner as in Example 1 except that the discharge amount of the resin composition B was 150 kg / hour (50 kg / hour per nozzle). The die swell rate was 1.37.
Within 3 hours of continuous molding, eyes were observed within 1 hour from the start of molding. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected and the weight was measured to be 12 mg. It was also confirmed that foreign matter (modified resin composition B) was mixed in the molded product (in this case, pellets).

<Reference example>
A full-scale electrodynamic vibration test device (BIG Wave manufactured by Asahi Seisakusho Co., Ltd.) is attached to the die portion of the resin extrusion die as the vibration generator 30 shown in FIG. 5, and vibrations of 20 Hz are applied in the vertical direction. Extruded the resin under the same conditions as in Example 3. When the amplitude and vibration speed of the die were measured in the same manner as in Example 3, the amplitude was 0.3 mm and the vibration speed was 35 mm / second.
The extruded strands vibrated greatly, the adjacent strands collided and fused together, and in that state, two pellets bonded to each other were obtained. Therefore, molding was stopped 3 minutes after the start. This method was judged to be impossible because individual pellets were not obtained individually.

  In all the above-mentioned examples and comparative examples, the strands were taken out, cooled, cut with a pelletizer, and pelletized. The strand take-up speed at that time was set so that the diameter of the strand was 3 mm. The strand expanded due to the ballast effect when exiting from the die nozzle and became larger than the nozzle diameter, but was then drawn according to the strand take-up speed to a diameter of 3 mm. Even if the take-off speed was changed, the expansion rate due to the ballast effect immediately after exiting the discharge nozzle (within 2 cm) did not change much.

<Example 17>
Resin extrusion die as shown in FIGS. 1-2 was produced using die steel SKD11. Three discharge nozzles 12 and three gas outlets 11 were provided at equal intervals in the direction of resin extrusion in the direction perpendicular to the paper surface of FIGS. The gas outlet 11 is circular with a diameter of 5.3 mm, and d = 0.5 mm, φd = 3 mm, φD = 3.2 mm in FIG. 2 (that is, the wall thickness Lt = 0.1 mm of the tip 12 a of the discharge nozzle 12). ), Α = 25 °, β = 35 °, and H = 1 mm.
A die for resin extrusion as shown in FIG. 1 was produced using the die steel SKD11. The maximum cross-sectional area of the die manifold was 670 mm ² , three discharge nozzles having a diameter of 3 mmφ and a length of 25 mm were arranged horizontally. The nozzle opening rate described above is 3.2%.

Toshiba TEM37BS was used for the extruder, and the conditions were a discharge rate of 60 kg / hour (that is, a discharge rate of 20 kg / hour per discharge nozzle) and a screw rotation speed of 500 rpm. As a thermoplastic resin composition, a resin composition (resin composition) containing 30% by weight of talc (TALKAN PAWDER PK-C manufactured by Hayashi Kasei Co., Ltd.) and 70% by weight of polycarbonate (Iupilon S3000 manufactured by Mitsubishi Engineering Plastics) A).
Extrusion was performed at a preset temperature of 250 ° C. of the extruder cylinder and resin extrusion die. The resin temperature is usually considered to be about 30 ° C. higher than the set temperature of the die.
The shear viscosity of the resin composition A was measured by CAPIROGRAPH-1C manufactured by TOYOSEIKI Co., Ltd. according to JIS-K7911 under the conditions of a temperature of 280 ° C. and a shear rate of 100 / sec. .

Moreover, the air heated to 150 degreeC was supplied from the gas supply port 14 so that the flow volume from each gas outflow port might be 10 liter / min in conversion of room temperature. The extruded strand of resin was photographed with a photograph, and the maximum diameter φD measured within 2 cm from the tip of the discharge nozzle for the strand extruded from the die was 3.66 mm. Since the inner diameter φd of the discharge nozzle is 3 mm, the diameter increase rate (die swell ratio) φD / φd = 1.22 due to the ballast effect. (In addition, since the expansion of the resin strand ends within 2 cm after being extruded, the maximum diameter within 2 cm from the tip of the discharge nozzle was measured.)
In addition, a small electrodynamic vibration test device (Wave Maker 01 manufactured by Asahi Seisakusho Co., Ltd.) is attached to the die portion of the resin extrusion die as the vibration generator 30 shown in FIG. 5, and a vibration of 20 Hz is applied in the vertical direction. Except that, the resin composition A was extruded under the same conditions as in Example 1. A pocketable vibrometer VM-63A “RIOVIBRO” manufactured by RION Co., Ltd. was pressed against the base, and the amount of vibration and vibration speed of the base were measured. As a result, the amplitude was 0.01 mm and the vibration speed was 1.0 mm / sec.

The strand coming out of the die was taken up at a take-up speed (Vs) = 42 m / min using a conveying and granulating configuration as shown in FIG. Two guide rollers having a diameter of 40 mm, a groove depth of 7.5 mm, and a groove pitch of 9 mm were used. As the guide roller 94A that first contacts the strand in the cooling tank 92, a guide roll capable of controlling the rotation speed is provided and rotated so that the peripheral speed (Vr) = 9 m / min (Vr / Vs = 0.2). ). The guide roller 94A is driven by using a small gear motor CNHM02-4085-AV-11 manufactured by Sumitomo Heavy Industries, Ltd. for the drive unit, and an inverter HF3202-A20 also manufactured by Sumitomo Heavy Industries, Ltd. Was used to control the rotation speed. As described above, the positive peripheral speed means that the rotation direction of the guide roller 94A is equal to the strand conveyance direction (that is, the rotation direction is opposite to that of the guide roller 94A in FIG. 7A). .
Extrusion was carried out continuously for 3 hours, but the occurrence of eyes and the foreign matter (modified resin composition A) mixed in the molded product (pellet) were not detected.
Therefore, the extrusion was continued for another 3 hours, and evaluation up to 6 hours was carried out. As a result, one pellet mixed with foreign matters was confirmed. In addition, after 6 hours, the slight eyes adhering to the periphery of the three discharge nozzles were collected, and the weight was measured to be only 2 mg.

<Example 18>
Extrusion molding was performed in the same manner as in Example 17 except that the nozzle length was 35 mm.
Extrusion was carried out continuously for 3 hours, but no molded product (pellet) with the occurrence of eyes and foreign matters (modified resin composition A) was detected. As a result of evaluation up to 6 hours, one pellet containing foreign matters was confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured, which was very small, 2 mg.

<Example 19>
Extrusion was carried out in the same manner as in Example 17 except that the nozzle diameter was not changed and the maximum cross-sectional area of the manifold was 352 mm ² and the nozzle opening ratio was 6%.
Extrusion was carried out continuously for 3 hours, but no molded product (pellet) with the occurrence of eyes and foreign matters (modified resin composition A) was detected. As a result of evaluation up to 6 hours, one pellet containing foreign matters was confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured, which was very small, 2 mg.

<Example 20>
Extrusion was carried out in the same manner as in Example 17 except that the number of nozzles was increased from 3 to 5 (nozzle opening ratio: S1 / S2 = 10.5%) and the discharge rate was 100 kg / hr.
When extrusion was carried out continuously for 3 hours, slight appearance was confirmed after 2 hours, but a molded product (pellet) mixed with foreign matter (modified resin composition A) was not detected. After 3 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured. When evaluation was performed for up to 6 hours, three pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 6 mg.

<Example 21>
Extrusion was carried out in the same manner as in Example 17 except that the number of nozzles was reduced from 3 to 1 (nozzle opening ratio: S1 / S2 = 1.0%) and the discharge rate was 20 kg / hr.
When extrusion was carried out continuously for 3 hours, slight appearance was confirmed after 2 hours, but a molded product (pellet) mixed with foreign matter (modified resin composition A) was not detected. After 3 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected and measured for a weight of only 3 mg. As a result of evaluation up to 6 hours, two pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 7 mg.

<Example 22>
Extrusion molding was performed in the same manner as in Example 17 except that the guide roller 94A was not rotated and the peripheral speed (Vr) was set to 0 (thus Vr / Vs = 0).
Extrusion was carried out continuously for 3 hours, but no molded product (pellet) with the occurrence of eyes and foreign matters (modified resin composition A) was detected. When the evaluation was performed for up to 6 hours, the generation of the eyes and the pellets contaminated with foreign matters were not detected even after 6 hours.

<Example 23>
Extrusion molding was performed in the same manner as in Example 17 except that the circumferential speed of the guide roller 94A was set to 42 m / min equal to the take-up speed of the resin strand.
Extrusion was carried out continuously for 3 hours, but no molded product (pellet) with the occurrence of eyes and foreign matters (modified resin composition A) was detected. As a result of evaluation up to 6 hours, four pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured, which was very small, 2 mg.

<Example 24>
Implemented except that the above-mentioned resin composition B was used as the thermoplastic resin composition, the resin strand take-up speed was 42 m / min, and the circumferential speed of the guide roller 94A was 6 m / min (Vr / Vs = 0.1). Extrusion molding was performed under the same conditions as in Example 17. The die swell ratio was 1.13, and the shear viscosity of the resin composition B was 130 Pa · sec under the conditions of a temperature of 280 ° C. and a shear rate of 100 / sec.
In the continuous molding for 3 hours, minute eyes and eyes were observed after 2 hours from the start, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes and eyes seemed to adhere to the surface of the extruded strands, no pellets contaminated with foreign matter (modified resin composition B) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. In addition, after 3 hours, the eyes and eyes adhering to the tip of the discharge nozzle were collected and the weight was measured.
As a result of evaluation up to 6 hours, two pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured, which was only 4 mg.

<Example 25>
Example except that the discharge rate was 45 kg / hour (15 kg / hour per nozzle), the resin strand take-up speed was 32 m / min, and the circumferential speed of the guide roller 94A was 8 m / min (Vr / Vs = 0.3). Extrusion molding was performed under the same conditions as in No.17. The die swell rate was 1.18.
In the continuous molding for 3 hours, minute eyes and eyes were observed after 2 hours from the start, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown-out eyes seemed to be attached to the surface of the extruded strand, pellets mixed with foreign matters (modified resin composition A) were not detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. In addition, after 3 hours, the eyes and eyes adhering to the tip of the discharge nozzle were collected and the weight was measured.
As a result of evaluation up to 6 hours, one pellet containing foreign matters was confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be very small at 5 mg.

<Example 26>
Extrusion molding was performed under the same conditions as in Example 17 except that the linear velocity of the air flow was 3 m / sec. The die swell rate was 1.22.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes seemed to adhere to the surface of the extruded strand, no pellets contaminated with foreign matter (modified resin composition A) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhered to the tip of the discharge nozzle were collected and the weight was measured to be 4 mg.
When evaluation was performed for up to 6 hours, three pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 12 mg.

<Example 27>
Extrusion molding was performed under the same conditions as in Example 17 except that the gap d between the gas outlet 11 and the outer peripheral surface of the discharge nozzle 12 was 1.1 mm and the linear velocity of the air flow was 10 m / sec. The die swell rate was 1.22.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes seemed to adhere to the surface of the extruded strand, no pellets contaminated with foreign matter (modified resin composition A) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhering to the tip of the discharge nozzle were collected and the weight was measured to be 6 mg.
When evaluation was performed for up to 6 hours, three pellets mixed with foreign matters were confirmed. In addition, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 15 mg.

<Example 28>
Extrusion molding was performed under the same conditions as in Example 17 except that the resin composition C described above was used as the resin composition and the peripheral speed of the guide roller 94A was set to 5 m / min. The die swell ratio was 1.04, and the shear viscosity of the resin composition C was 80 Pa · sec under the conditions of a temperature of 280 ° C. and a shear rate of 100 / sec.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes and eyes seemed to adhere to the surface of the extruded strand, no pellets contaminated with foreign matter (modified resin composition C) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhered to the tip of the discharge nozzle were collected and the weight was measured to be 5 mg.
As a result of evaluation up to 6 hours, four pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 13 mg.

<Example 29>
Extrusion molding was performed under the same conditions as in Example 17 except that the resin composition D described above was used as the resin composition and the peripheral speed of the guide roller 94A was set to 5 m / min. The die swell ratio was 1.03, and the shear viscosity of the resin composition D was 40 Pa · sec under the conditions of a temperature of 280 ° C. and a shear rate of 100 / sec.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown-out eyes seemed to adhere to the surface of the extruded strand, pellets mixed with foreign matter (modified resin composition D) were not detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhered to the tip of the discharge nozzle were collected and the weight was measured to be 8 mg.
As a result of evaluation up to 6 hours, two pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 17 mg.

<Example 30>
Extrusion molding was performed in the same manner as in Example 29 except that the rotation of the guide roller 94A was stopped (Vr = 0, Vr / Vs = 0).
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown-out eyes seemed to adhere to the surface of the extruded strand, pellets mixed with foreign matter (modified resin composition D) were not detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhering to the tip of the discharge nozzle were collected, and the weight was measured to be 7 mg.
Even when the evaluation was performed for up to 6 hours, no pellets containing foreign matters were detected. In addition, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 15 mg.

<Example 31>
Extrusion molding was performed in the same manner as in Example 29 except that the rotation speed (Vr) of the guide roller 94A was 42 m / min (Vr / Vs = 1.0).
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown-out eyes seemed to adhere to the surface of the extruded strand, pellets mixed with foreign matter (modified resin composition D) were not detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhering to the tip of the discharge nozzle were collected, and the weight was measured to be 7 mg.
As a result of evaluation up to 6 hours, six pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 16 mg.

<Example 32>
The experiment was performed in the same manner as in Example 17 except that the inner diameter φd of the protruding nozzle was 8 mm (nozzle opening ratio: S1 / S2 = 22.5%) and the peripheral speed of the guide roller 94A was 12 m / min. The die swell rate was 1.17.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes seemed to adhere to the surface of the extruded strand, no pellets contaminated with foreign matter (modified resin composition A) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhered to the tip of the discharge nozzle were collected, and the weight was 9 mg.
When evaluation was performed for up to 6 hours, three pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 21 mg.

<Example 33>
An experiment was conducted in the same manner as in Example 17 except that the vibration generator was not used.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. A part of the blown-out eyes seemed to be attached to the surface of the extruded strand, but pellets mixed with foreign matter (modified resin composition A) were not detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhering to the tip of the discharge nozzle were collected, and the weight was measured to be 7 mg.
As a result of evaluation up to 6 hours, two pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 13 mg.

<Example 34>
The experiment was performed in the same manner as in Example 17 except that the above-described resin composition E was used as the thermoplastic resin composition and the peripheral speed of the guide roller 94A was set to 11 m / min.
The shear viscosity of the resin composition E was measured by a method based on JIS-K7911 using CAP-ROGRAPH-1C manufactured by TOYOSEIKI Co., Ltd. under the conditions of a temperature of 280 ° C. and a shear rate of 100 / sec. . The die swell rate was 1.27.
In the continuous molding for 3 hours, minute eyes and eyes were observed after 2 hours from the start, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown-out eyes seemed to adhere to the surface of the extruded strand, but no pellets contaminated with foreign matter (modified resin composition E) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhering to the tip of the discharge nozzle were collected, and the weight was measured to be 3 mg.
As a result of evaluation up to 6 hours, two pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 8 mg.

<Example 35>
Experiments were conducted in the same manner as in Example 17 except that the above-described resin composition F was used as the thermoplastic resin composition and the peripheral speed of the guide roller 94A was set to 12 m / min.
The shear viscosity of the resin composition E was 6000 Pa · sec when measured by a method based on JIS-K7911 using CAPIROGRAPH-1C manufactured by TOYOSEIKI under the conditions of a temperature of 280 ° C. and a shear rate of 100 / sec. . The die swell rate was 1.33.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown-out eyes and eyes seemed to adhere to the surface of the extruded strands, but no pellets contaminated with foreign matter (modified resin composition F) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhered to the tip of the discharge nozzle were collected, and the weight was 9 mg. Further, during the extrusion, four strand breaks, which are thought to be caused by strand foaming, occurred four times.
As a result of evaluation up to 6 hours, two pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 21 mg.

<Example 36>
Extrusion molding was performed in the same manner as in Example 35 except that the rotation of the guide roller 94A was stopped (Vr = 0, Vr / Vs = 0).
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown-out eyes and eyes seemed to adhere to the surface of the extruded strands, but no pellets contaminated with foreign matter (modified resin composition F) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhering to the tip of the discharge nozzle were collected and the weight was measured to be 10 mg.
As a result of evaluation up to 6 hours, one pellet containing foreign matters was confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 17 mg.

<Example 37>
Extrusion molding was performed in the same manner as in Example 35 except that the rotation speed (Vr) of the guide roller 94A was 42 m / min (Vr / Vs = 1.0).
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Some of the blown-out eyes and eyes seemed to adhere to the surface of the extruded strands, but no pellets contaminated with foreign matter (modified resin composition F) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhered to the tip of the discharge nozzle were collected and the weight was measured to be 8 mg.
As a result of evaluation up to 6 hours, six pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was 18 mg.

<Example 38>
The discharge amount of the resin composition A is 84 kg / hour (28 kg / hour per nozzle), the take-up speed of the resin strand is 59 m / min, and the peripheral speed of the guide roller 94A is 12 m / min (Vr / Vs = 0.2). Except that, extrusion molding was performed under the same conditions as in Example 17. The die swell rate was 1.25.
In the continuous molding for 3 hours, minute eyes and eyes were observed after 2 hours from the start, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes seemed to adhere to the surface of the extruded strand, no pellets contaminated with foreign matter (modified resin composition A) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes attached to the tip of the discharge nozzle were collected, and the weight was measured to be 1 mg.
As a result of evaluation up to 6 hours, one pellet containing foreign matters was confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured, which was only 4 mg.

<Example 39>
The discharge amount of the resin composition A is 105 kg / hour (35 kg / hour per nozzle), the take-up speed of the resin strand is 74 m / min, and the peripheral speed of the guide roller 94A is 13 m / min (Vr / Vs = 0.2). Except that, extrusion molding was performed under the same conditions as in Example 17. The die swell rate was 1.26.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes seemed to adhere to the surface of the extruded strand, no pellets contaminated with foreign matter (modified resin composition A) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhered to the tip of the discharge nozzle were collected and the weight was measured to be 4 mg.
As a result of evaluation up to 6 hours, two pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 14 mg.

<Example 40>
Same as Example 17 except that the thickness Lt = (φD−φd) / 2 of the discharge nozzle tip is 0.7 mm and the peripheral speed of the guide roller 94A is 19 m / min (Vr / Vs = 0.5). Extrusion molding was performed under the conditions.
In the continuous molding for 3 hours, minute eyes and eyes were observed after 2 hours from the start, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes seemed to adhere to the surface of the extruded strand, no pellets contaminated with foreign matter (modified resin composition A) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhering to the tip of the discharge nozzle were collected, and the weight was measured to be 3 mg.
When evaluation was performed for up to 6 hours, three pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 11 mg.

<Example 41>
Extrusion molding was performed under the same conditions as in Example 17 except that the thickness Lt = (φD−φd) / 2 of the discharge nozzle tip was 1.5 mm.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes seemed to adhere to the surface of the extruded strand, no pellets contaminated with foreign matter (modified resin composition A) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhered to the tip of the discharge nozzle were collected and the weight was measured to be 8 mg.
As a result of evaluation up to 6 hours, one pellet containing foreign matters was confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was 23 mg.

<Example 42>
Extrusion molding was performed in the same manner as in Example 41 except that the rotation of the guide roller 94A was stopped (Vr = 0, Vr / Vs = 0).
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes seemed to adhere to the surface of the extruded strand, no pellets contaminated with foreign matter (modified resin composition A) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhered to the tip of the discharge nozzle were collected, and the weight was 9 mg.
Even when the evaluation was performed for up to 6 hours, no pellets containing foreign matters were detected. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 24 mg.

<Example 43>
Extrusion molding was performed in the same manner as in Example 41 except that the rotation speed (Vr) of the guide roller 94A was 25 m / min (Vr / Vs = 0.6).
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes seemed to adhere to the surface of the extruded strand, no pellets contaminated with foreign matter (modified resin composition A) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhered to the tip of the discharge nozzle were collected, and the weight was 9 mg.
As a result of evaluation up to 6 hours, one pellet containing foreign matters was confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 24 mg.

<Example 44>
Extrusion molding was performed in the same manner as in Example 41 except that the rotation speed (Vr) of the guide roller 94A was 42 m / min (Vr / Vs = 1.0).
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes seemed to adhere to the surface of the extruded strand, no pellets contaminated with foreign matter (modified resin composition A) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhering to the tip of the discharge nozzle were collected, and the weight was measured to be 7 mg.
As a result of evaluation up to 6 hours, 5 pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was 25 mg.

<Example 45>
Extrusion molding was performed under the same conditions as in Example 17 except that the length of the discharge nozzle was 14 mm.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Although some of the blown eyes seemed to adhere to the surface of the extruded strand, no pellets contaminated with foreign matter (modified resin composition A) were detected. It was considered that the deterioration was not progressing and there were minute eyes, so that it was diffused and absorbed on the surface of the strand or removed by friction with the guide roller 94A. Further, after 3 hours, the eyes and eyes adhering to the tip of the discharge nozzle were collected, and the weight was measured to be 7 mg.
As a result of evaluation up to 6 hours, two pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 13 mg.

<Example 46>
Extrusion molding was performed under the same conditions as in Example 17 except that the length of the discharge nozzle was 52 mm.
Among the moldings continued for 3 hours, minute eyes and eyes were observed from about 1 hour after the initiation of molding, but they were blown away in the state of minute objects and did not accumulate greatly. Further, when the pellets were examined after the elapse of 3 hours, five pellets mixed with foreign matters (modified resin composition A) were confirmed. Further, after 3 hours, the eyes and eyes adhered to the tip of the discharge nozzle were collected and the weight was measured to be 14 mg.
When evaluation was performed for up to 6 hours, nine pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 29 mg.

<Comparative Example 5>
Same as Example 17 except that the thickness Lt = (φD−φd) / 2 of the discharge nozzle tip is 2.1 mm and the peripheral speed of the guide roller 94A is 19 m / min (Vr / Vs = 0.5). Extrusion molding was performed under the conditions.
Of the moldings that were continued for 3 hours, the occurrence of eyes was observed within 1 hour from the start of molding. Further, after 3 hours, the eyes and eyes adhered to the tip of the discharge nozzle were collected and the weight was measured to be 32 mg. Further, six pellets mixed with foreign matter (modified resin composition A) were confirmed. When evaluation was performed for up to 6 hours, 15 pellets containing foreign substances were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 65 mg.

<Comparative Example 6>
The discharge amount of the resin composition A was 30 kg / hour (10 kg / hour per nozzle), the strand take-up speed was 21 m / min, and the peripheral speed of the guide roller 94A was 7 m / min (Vr / Vs = 0.3). Except that, extrusion molding was performed under the same conditions as in Example 17. The die swell rate was 1.09.
Of the moldings that were continued for 3 hours, the occurrence of eyes was observed within 1 hour from the start of molding. Further, after 3 hours, the eyes and eyes adhering to the tip of the discharge nozzle were collected and the weight was measured to be 17 mg. Further, 11 pellets mixed with foreign matter (modified resin composition A) were confirmed. When evaluation was performed for up to 6 hours, 22 pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected and the weight was measured to be 41 mg.

<Comparative Example 7>
All the experiments were performed in the same manner as in Comparative Example 6 except that the vibration generator was not used. When a pocketable vibrometer VM-63A “RIOVIBRO” manufactured by RION Co., Ltd. was pressed against the base and the vibration amount and vibration speed of the base were measured, the amplitude was 0.008 mm and the vibration speed was 0.32 mm / second. This is considered that the vibration of the extruder propagated to the die.
Of the moldings that were continued for 3 hours, the occurrence of eyes was observed within 1 hour from the start of molding. In addition, after 3 hours, a slight eye adhered to the tips of the three discharge nozzles was collected and the weight was 23 mg. In addition, 17 pellets mixed with foreign matter (modified resin composition A) were confirmed. When evaluation was performed for up to 6 hours, 24 pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected, and the weight was measured to be 44 mg.

<Comparative Example 8>
The discharge amount of the resin composition B was 150 kg / hour (50 kg / hour per nozzle), the strand take-up speed was 105 m / min, and the peripheral speed of the guide roller 94A was 24 m / min (Vr / Vs = 0.2). Except that, the experiment was performed in the same manner as in Example 17. The die swell rate was 1.37.
Within 3 hours of continuous molding, eyes were observed within 1 hour from the start of molding. In addition, after 3 hours, a slight eye adhered to the tip of the discharge nozzle was collected, and the weight was measured to be 12 mg. Further, 13 pellets mixed with foreign matter (modified resin composition A) were confirmed. As a result of evaluation up to 6 hours, 29 pellets mixed with foreign matters were confirmed. Further, after 6 hours, the eyes and eyes adhering to the periphery of the discharge nozzle were collected and the weight was measured to be 37 mg.

The conditions and evaluation results of the above examples and comparative examples are shown below.

  As described above, according to the present invention, when the air flow flowing along the outer peripheral surface of the discharge nozzle tip is blown onto the resin strand extruded from the discharge nozzle while being extruded, the thickness Lt of the tip is 0. Using a discharge nozzle satisfying <Lt ≦ 2 mm and setting the discharge amount from the discharge nozzle to 14 kg / hour or more and 40 kg / hour or less, the gas hits the expanded portion of the molten resin due to the ballast effect, And the deposition on the generated eyes can be suppressed.

Claims (9)

A method of extruding a thermoplastic resin composition from the discharge nozzle using an extrusion apparatus equipped with a base having a discharge nozzle,
While using a discharge nozzle having a wall thickness Lt of the tip portion of 0 <Lt ≦ 2 mm and blowing gas to the vicinity of the tip portion of the discharge nozzle, the discharge amount is 14 kg / hour or more and 40 kg / hour or less per discharge nozzle. By extruding the thermoplastic resin composition, the thermoplastic resin composition is expanded by the ballast effect in the vicinity of the tip of the discharge nozzle, and the flow of the gas is changed in the expanded portion, and the extruded thermoplastic resin While suppressing a part of the composition from depositing on the tip of the discharge nozzle ,
The expansion rate due to the ballast effect of the thermoplastic resin composition is such that the inner diameter of the discharge nozzle is φd, the diameter of the resin strand after the thermoplastic resin composition is extruded from the discharge nozzle in a strand shape and expanded is D In this case, the ejection amount is determined so as to satisfy 1.35 ≧ D / φd ≧ 1.05 . A method for extruding a thermoplastic resin composition, comprising: Shear viscosity, temperature 280 ° C., 50 Pa · sec or more at a shear rate of 100 / sec, extruding the thermoplastic resin composition of claim 1 Symbol mounting is characterized by using thermoplastic resin composition is not more than 5000 Pa · sec Molding method. The method for extruding a thermoplastic resin composition according to claim 1 or 2, wherein a linear velocity of the gas in the vicinity of a tip portion of the discharge nozzle is 4 to 100 m / sec. The method for extruding a thermoplastic resin composition according to any one of claims 1 to 3 , wherein a discharge nozzle having an inner diameter of 2 to 7 mm is used as the discharge nozzle. The base has a gas outlet that forms a gap around the tip of the discharge nozzle, and covers at least a part of the base so as to form a space between the base and the gas outlet. Is provided,
The thermoplastic resin according to any one of claims 1 to 4 , wherein the gap is 0.1 to 1 mm, and the gas is blown from the gas outlet to the vicinity of the tip of the discharge nozzle. A method for extruding the composition. Furthermore, the thermoplastic resin composition is extruded while the base and the cover are vibrated at an amplitude of 0.005 mm to 0.2 mm and a vibration speed of 0.3 mm / second to 5 mm / second. Item 6. A method for extruding the thermoplastic resin composition according to Item 5 . The base is provided with a manifold for making the pressure of the thermoplastic resin composition supplied from the extrusion device uniform and supplying the pressure to the discharge nozzle,
Each of the plurality of discharge nozzles is determined by a ratio S1 / S2 between the total area (S1) of the minimum cross-sectional area perpendicular to the push-out direction and the maximum cross-sectional area (S2) perpendicular to the push-out direction of the manifold. The method for extruding a thermoplastic resin composition according to any one of claims 1 to 6 , wherein the nozzle opening ratio is 10%? S1 / S2? 1.2%. Extrusion method of the thermoplastic resin composition according to any one of claims 1 to 7, wherein the length L of the discharge nozzle is 50 mm ≧ L ≧ 15 mm. The resin strand made of the thermoplastic resin composition pushed out from the discharge nozzle is drawn at a take-off speed Vs (m / min) so as to be in contact with a guide roller provided in the conveyance path of the resin strand,
When the moving speed of the outer peripheral surface of the guide roller in contact with the resin strand is Vr (m / min), the take-up speed and the take-up speed are set so as to satisfy the relationship of 0.7 ≧ Vr / Vs ≧ −0.2. The method for extruding a thermoplastic resin composition according to any one of claims 1 to 8 , wherein a moving speed and a rotation direction of the guide roller are determined.

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