Method and apparatus for manufacturing resin pellets containing reinforcing fibers

Abstract

This invention provides a method and apparatus for manufacturing resin granules containing reinforcing fibers. When manufacturing granules containing long-length reinforcing fibers, even when using a wide-width die with a long die length, the granules are stable, resulting in an excellent appearance and superior mechanical properties. The method for manufacturing resin granules containing reinforcing fibers includes: feeding resin into a twin-screw extruder from a position closer to the inlet side than the first mixing section, and melting and mixing the resin in the first mixing section; feeding reinforcing fibers into the twin-screw extruder from a position closer to the outlet side than the first mixing section and closer to the inlet side than the second mixing section, and further melting and mixing the resin in the presence of the reinforcing fibers; and extruding the melt-mixed resin containing reinforcing fibers from the nozzle outlet of the die in the form of a granule containing reinforcing fibers, wherein the combination of the base and the die with the nozzle satisfies specific conditions. The resin granule manufacturing apparatus containing reinforcing fibers used in this method has a twin-screw extruder and a die head disposed at the outlet of the twin-screw extruder. The twin-screw extruder has a first mixing section and a second mixing section disposed at a position closer to the outlet side than the first mixing section. The second mixing section has a notched reverse conveying screw element and / or includes a reverse conveying kneading disc.

Description

Technical Field

[0001] This invention relates to a method and apparatus for manufacturing resin granules containing reinforcing fibers, and more specifically, to a method and apparatus for manufacturing resin granules containing short fibers that have excellent productivity and possess mechanical properties equivalent to those of long-fiber reinforced resin granules. Background Technology

[0002] Resin granules containing reinforcing fibers are used in various applications such as automotive parts and OA equipment due to their excellent mechanical properties. A conventional method for manufacturing resin granules containing reinforcing fibers involves feeding thermoplastic resin into an extruder and melting it, then feeding fibers into the molten thermoplastic resin, mixing and kneading the thermoplastic resin and glass fibers within the extruder, and finally extruding the mixture from the nozzle of a die as a strand, followed by cutting it into granules. In the extruder, kneading typically uses a screw such as a kneading disc. It is known, as disclosed in Patent Document 1, that using a screw with multiple notches on a reverse-feeding screw disc offers advantages such as improved kneading performance and simplified screw structure in the kneading section.

[0003] Regarding resin granules containing reinforcing fibers, it is known that when the length of the residual fibers present in the granules is long, high-strength molded articles can be obtained. However, when manufacturing resin granules containing reinforcing fibers, if long-length reinforcing fibers are used, the reinforcing fibers may break during mixing or stranding using a die, resulting in shorter fiber lengths of the residual fibers in the granules, and sometimes unsatisfactory mechanical properties cannot be obtained.

[0004] Methods for manufacturing resin granules containing reinforcing fibers with long residual fibers are known, such as: a method for manufacturing granules using an extrusion die including a die orifice having a conical portion, as disclosed in Patent Document 2; and a method for using glass fiber reinforced thermoplastic resin granules with a high glass fiber content as a glass masterbatch and adding other resins thereto, as disclosed in Patent Document 3.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2002-120271 Patent Document 2: Japanese Patent Application Publication No. 08-001662 Patent Document 3: Japanese Patent Application Publication No. 2003-183411 Patent Document 4: Japanese Patent Application Publication No. 2022-154027 Summary of the Invention

[0006] The technical problem that the invention aims to solve As described above, while superior mechanical properties can be achieved when the residual fibers in the granules are long, resin granules containing reinforcing fibers with long residual fibers also present the following problems: decreased productivity due to the inability to stably manufacture strands using a standard die; difficulty in injection molding due to the material not falling from the hopper during molding; and a deterioration in the appearance of the molded body due to some fibers failing to open during molding. Even using the die described in Patent Document 2 cannot improve injection molding performance and appearance. Furthermore, when using the neutral element with a screw concave-convex surface forming part described in Patent Document 2 for melt mixing, the fibers break inside the extruder, resulting in shorter reinforcing fiber lengths in the granules. Moreover, expensive specialized manufacturing equipment is required to manufacture long-fiber reinforced resin granules with granule lengths equal to the fiber lengths in the granules.

[0007] Therefore, there is a desire to develop a method for manufacturing resin granules containing reinforcing fibers that eliminates the need for specialized equipment for manufacturing long-fiber reinforced resin granules, facilitates injection molding even with long residual fibers in the granules, produces excellent appearance, and exhibits superior mechanical properties. Patent Document 4 discloses a method for manufacturing resin granules containing reinforcing fibers developed to address this need.

[0008] However, the inventors of this invention have discovered through research that, as shown in Patent Document 4, even when using a long die with a long die head, there is still a problem of unstable granules when using medium- or large-scale resin granule manufacturing equipment with reinforced fibers and a wide die head.

[0009] That is, in a large-scale resin granule manufacturing plant containing reinforced fibers, once the extruded material flows into the die head, it will spread laterally within the die head support and be supplied downstream to multiple front nozzles.

[0010] Because the resin is oriented along the wall within the die holder, the flow rate of the nozzles at both ends is greater than that of the nozzle closer to the center due to the shear flow characteristic of fibrous materials.

[0011] Therefore, the inventors of this invention have discovered through research that, in the case of using medium- to large-scale resin granule manufacturing apparatuses with wide die widths, such as Figure 14 As shown, there is a problem that the extruded material from the nozzles at both ends is loose and the material becomes unstable.

[0012] The present invention aims to provide a method and apparatus for manufacturing resin granules containing reinforcing fibers. When manufacturing granules containing reinforcing fibers with long fiber lengths, even when using a die with a wide width and long die length, the granules can be stabilized, the molded body has an excellent appearance, and it can exhibit excellent mechanical properties.

[0013] Technical means for solving technical problems This invention relates, for example, to the following [1] to

[12] .

[0014] [1] A method for manufacturing resin granules containing reinforcing fibers, wherein, The extruder uses a twin-screw extruder and a die head disposed at the outlet of the twin-screw extruder. The twin-screw extruder has a first mixing section and a second mixing section disposed at a position closer to the outlet side than the first mixing section. The second mixing section has a notched reverse conveying screw element and / or includes a reverse conveying kneading disc. The aforementioned mold head includes a nozzle mold head with a nozzle and a base. The aforementioned base has an opening, which includes an inlet and an outlet connected to the aforementioned nozzle. The above manufacturing method includes: The process of supplying resin into the twin-screw extruder from a position closer to the inlet side than the first mixing section, and performing melt mixing of the resin in the first mixing section; The process of feeding reinforcing fibers into the twin-screw extruder from a position closer to the outlet than the first mixing section and closer to the inlet than the second mixing section, and further melt-mixing the resin in the presence of the reinforcing fibers; and The process involves extruding the melt-blended resin containing reinforcing fibers from the nozzle outlet of the aforementioned nozzle die in the form of a strand of resin containing reinforcing fibers. The above-mentioned nozzle and the above-mentioned base satisfy (1) to (8). The width of the aforementioned nozzle die head is 94 mm or more, and the number of nozzles arranged inside the aforementioned die head is 5 to 70. On the aforementioned base, the aforementioned openings are arranged in a row in the horizontal direction. The resin described above is a propylene-based polymer with a melt flow rate of 20–500 g / 10 min at 230°C and a load of 2.16 kg. The fiber length of the aforementioned reinforcing fibers is between 2.5 mm and 8 mm. The diameter of the aforementioned reinforcing fibers is greater than 5 μm and less than 17 μm. The resin granules containing reinforcing fibers contain 5% to 50% by mass of the aforementioned reinforcing fibers and 50% to 95% by mass of the aforementioned resin (the total of reinforcing fibers and resin is 100% by mass).

[0015] (1) The nozzle flow path length is more than 60mm and less than 150mm.

[0016] (2) The cross-sectional area (S1) of the minimum cross-sectional area portion of the opening of the above-mentioned base is 6 mm. 2 Above 80mm 2 the following.

[0017] (3) The cross-sectional area (S0) of the nozzle outlet is 3 mm. 2 Above 20mm 2 the following.

[0018] (4) The relationship S1≥S0 holds true.

[0019] (5) In the openings formed by the above-mentioned base, the proportion of the number of non-standard aperture openings at both ends is less than 20% of the total number.

[0020] (6) In the opening formed by the above-mentioned base, the ratio of the diameter of the opening at both ends to the standard diameter is between 50% and 98%.

[0021] (7) In the openings formed by the above-mentioned base, the proportion of the number of non-standard diameter central openings is less than 20% of the total number.

[0022] (8) In the opening formed by the base described above, the ratio of the diameter of the central opening to the standard diameter is between 70% and 100%.

[0023] [2] The method for manufacturing resin granules containing reinforcing fibers as described in [1], wherein the nozzle outlets of the nozzle die head are arranged in a row in the horizontal direction, or the nozzle outlets are arranged in two rows in the upper and lower directions and are staggered.

[0024] [3] A method for manufacturing resin granules containing reinforcing fibers as described in [1], wherein the base satisfying (9) above is used.

[0025] (9) In the openings formed by the base, when there are multiple non-standard aperture openings, the cross-sectional area of ​​the outermost (end) opening is less than or equal to the cross-sectional area of ​​the non-standard aperture opening that is not located at the outermost (end) and is less than the cross-sectional area of ​​the standard aperture opening.

[0026] [4] The method for manufacturing resin granules containing reinforcing fibers as described in [1], wherein the propylene polymer is an isotactic propylene homopolymer.

[0027] [5] The method for manufacturing resin granules containing reinforcing fibers as described in [1], wherein the reinforcing fibers are glass fibers or carbon fibers.

[0028] [6] The method for manufacturing resin granules containing reinforcing fibers as described in [1], wherein the screw speed of the twin-screw extruder is 250 rpm or more and 800 rpm or less.

[0029] [7] The method for manufacturing resin granules containing reinforcing fibers as described in [1], wherein the set temperature from the first mixing section of the twin-screw extruder to the nozzle is 240°C or more and 290°C or less.

[0030] [8] The method for manufacturing resin granules containing reinforcing fibers as described in [1], wherein the notched reverse conveying screw element is a single-threaded screw with L / D (screw length / screw diameter) = 1 and a lead of 0.25D or more and 0.5D or less.

[0031] [9] An apparatus for manufacturing resin granules containing reinforcing fibers, comprising: A twin-screw extruder having a first mixing section and a second mixing section disposed closer to the outlet side than the first mixing section, the second mixing section having a notched reverse conveying screw element and / or including a reverse conveying kneading disc; and The die head located at the outlet of the twin-screw extruder. The aforementioned mold head includes a nozzle mold head with a nozzle and a base. The base has an opening, which includes an inlet and an outlet connected to the nozzle, and the nozzle and the base satisfy (1) to (8). The width of the aforementioned nozzle die head is 94 mm or more, and the number of nozzles arranged inside the aforementioned nozzle die head is 5 to 70. On the aforementioned base, the aforementioned openings are arranged in a row in the horizontal direction.

[0032] (1) The nozzle flow path length is more than 60mm and less than 150mm.

[0033] (2) The cross-sectional area (S1) of the minimum cross-sectional area portion of the opening of the above-mentioned base is 6 mm. 2 Above 80mm 2 the following.

[0034] (3) The cross-sectional area (S0) of the nozzle outlet is 3 mm. 2 Above 20mm 2 the following.

[0035] (4) The relationship S1≥S0 holds true.

[0036] (5) In the openings formed by the above-mentioned base, the proportion of the number of non-standard aperture openings at both ends is less than 20% of the total number.

[0037] (6) In the opening formed by the above-mentioned base, the ratio of the diameter of the opening at both ends to the standard diameter is between 50% and 98%.

[0038] (7) In the openings formed by the above-mentioned base, the proportion of the number of non-standard diameter central openings is less than 20% of the total number.

[0039] (8) In the opening formed by the base described above, the ratio of the diameter of the central opening to the standard diameter is between 70% and 100%.

[0040]

[10] The apparatus for manufacturing resin granules containing reinforcing fibers as described in [9], wherein the nozzle outlets of the nozzle die are arranged in a row in the horizontal direction, or the nozzle outlets are arranged in two rows in the vertical direction and staggered.

[0041]

[11] The apparatus for manufacturing resin granules containing reinforcing fibers as described in [9], wherein the base satisfies the above-described condition (9).

[0042] (9) In the openings formed by the base, when there are multiple non-standard aperture openings, the cross-sectional area of ​​the outermost (end) opening is less than or equal to the cross-sectional area of ​​the non-standard aperture opening and the cross-sectional area of ​​the standard aperture opening.

[0043]

[12] The apparatus for manufacturing resin granules containing reinforcing fibers as described in [9], wherein the notched reverse conveying screw element is a single-threaded screw with L / D = 1 and a lead of 0.25D or more and 0.5D or less.

[0044] Invention Effects The method and apparatus for manufacturing resin granules containing reinforcing fibers of the present invention can manufacture short fiber reinforced resin granules with long residual fiber lengths, improve the continuous production rate of the strands at both ends, and can manufacture resin granules containing reinforcing fibers with excellent mechanical properties equivalent to those of long fiber reinforced resin granules. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of a longitudinal section of a twin-screw extruder and a die head, as a specific example of the twin-screw extruder and die head used in the method for manufacturing resin granules containing reinforcing fibers according to the present invention, viewed from the horizontal direction.

[0046] Figure 2 It is Figure 1 The image shown is an enlarged view of the mold head.

[0047] Figure 3 It means Figure 2 An example of a diagram showing an outlet with multiple openings formed on the downstream side of the base of the mold head.

[0048] Figure 4 This is a schematic diagram of a longitudinal section including the nozzle, viewed from the horizontal direction, of a die head that includes a nozzle that has only a parallel section and no tapered section.

[0049] Figure 5 This is a schematic diagram of a longitudinal section including the nozzle, viewed from the horizontal direction, of a die head that includes a nozzle that has only a tapered portion and no parallel portion.

[0050] Figure 6 This is a diagram illustrating an example of a kneading disc that includes reverse conveying.

[0051] Figure 7 This is an explanatory diagram showing the structure of the screw used in Example 1.

[0052] Figure 8 This is a table showing the parameters and evaluation results of Examples 1-4 and Comparative Example 1.

[0053] Figure 9 This is a diagram showing the aperture of the opening formed on the base used in Examples 1-4 and Comparative Example 1.

[0054] Figure 10 This is a table showing the parameters and evaluation results of Examples 5-7 and Comparative Example 2.

[0055] Figure 11 This is a diagram showing the aperture of the opening formed on the base used in Examples 5-7 and Comparative Example 2.

[0056] Figure 12 This is a schematic diagram showing the cross-section of a mold head with a base having a tapered opening.

[0057] Figure 13 This is a diagram showing the staggered arrangement of nozzle outlets on a nozzle die head.

[0058] Figure 14 This diagram illustrates the relaxed state of the resin pellets during the production of large-scale resin pellets containing reinforcing fibers using a long die head. Detailed Implementation

[0059] The method and apparatus for manufacturing resin granules containing reinforcing fibers of the present invention use a twin-screw extruder and a die.

[0060] The aforementioned twin-screw extruder has a first mixing section and a second mixing section disposed closer to the outlet side than the first mixing section. The second mixing section has a reverse-feeding screw element and / or includes a reverse-feeding kneading disc. The aforementioned die head is disposed at the outlet of the aforementioned twin-screw extruder and has a nozzle die head and a base, wherein the nozzle die head is a die head with a nozzle. A schematic longitudinal section of a specific example of the twin-screw extruder and die head used in the method for manufacturing resin granules containing reinforcing fibers of the present invention, viewed from the horizontal direction, is shown below. Figure 1 .

[0061] Figure 1 The twin-screw extruder 1 shown has a barrel 3 and screws 4 housed in the inner bore of the barrel 3. The twin-screw extruder 1 has two screws 4 in the horizontal direction. The twin-screw extruder 1 has a first mixing section 5 and a second mixing section 6 located closer to the outlet B side than the first mixing section 5. The second mixing section 6 has a reverse-feed screw element and / or includes a reverse-feed kneading disc (not shown). Furthermore, the twin-screw extruder 1 has a resin supply section 7 located closer to the inlet A side than the first mixing section, and a fiber supply section 8 located closer to the outlet B side than the first mixing section 5 and closer to the inlet A side than the second mixing section 6.

[0062] The outlet B of the twin-screw extruder 1 is equipped with a die head 2 for extruding the melt-blended resin containing reinforcing fibers in the form of a strand of resin containing reinforcing fibers. Figure 2 yes Figure 1 An enlarged view of the mold head 2 shown. Figure 2 As shown, the mold head 2 includes a mold head support 12, a base 13, and a nozzle mold head 14. Furthermore, a space forming a resin flow path is formed within the mold head 2, directly connected to and penetrating the inner bore of the barrel 3. This space is composed of a support space 15 within the mold head support 12, an opening 16 within the base 13, and a nozzle 9 within the nozzle mold head 14. This space has a bristle-like shape, converging into one line on the upstream side and branching into multiple lines on the downstream side.

[0063] The upstream end of the die holder 12 is directly connected to the inner bore of the barrel 3, forming a resin inlet 20, which serves as the entrance for the resin flow path. This inlet is mounted on the twin-screw extruder 1. The internal space 15 of the holder is configured such that its height narrows downstream and its width gradually expands horizontally. The internal space 15 has a resin inlet 20 on the upstream side and multiple resin outlets on the downstream side. Within the internal space 15, from upstream to downstream, a space branches into multiple channels.

[0064] The base 13 is a component mounted on the die head support 12, and its interior has openings 16 that form resin flow paths. Multiple opening outlets 16B are arranged in a horizontal row. In the method for manufacturing resin granules containing reinforcing fibers of the present invention, the number of nozzle inlets 10 in the die head 2 is not limited.

[0065] The nozzle die 14 is a component mounted on the base 13, and the nozzle die 14 is provided with a plurality of (14 to 40) nozzles 9. Each nozzle 9 is, for example, a circular hole that penetrates the nozzle die 14 in the horizontal direction. A nozzle inlet 10 is formed on the side of the twin-screw extruder 1, and a nozzle outlet 11 is formed on the side opposite to the twin-screw extruder 1.

[0066] like Figure 2 As shown, the nozzle 9 has a parallel portion 9b extending toward the nozzle inlet 10 and a tapered portion 9a on the nozzle outlet 11 side that decreases in a certain ratio with respect to the diameter toward the nozzle outlet 11. Figure 2 In this context, the horizontal length of nozzle 9, i.e., the nozzle flow path length, is denoted as L1, and the horizontal length of parallel part 9b, i.e., the parallel flow path length, is denoted as L2.

[0067] The nozzle die and base used in the manufacturing method and manufacturing apparatus for the resin granules containing reinforced fibers of the present invention satisfy the following requirements (1) to (4).

[0068] (1) The nozzle flow path length is more than 60mm and less than 150mm.

[0069] Regarding the nozzle flow path length, Figures 1-3 In the nozzle 9 shown, is Figure 2 The length shown in L1.

[0070] The nozzle flow path length is 60mm to 150mm, preferably 80mm to 140mm, and more preferably 100mm to 130mm.

[0071] When the nozzle flow path length is less than 60 mm, and when using reinforcing fibers with the fiber length of this invention, the fibers cannot be oriented along the flow direction. At the outlet of the nozzle die 14, the fibers fly out of the strand, making stable and continuous extrusion and collection of the strand impossible. Sometimes, fibers also fly out of the resulting granules. Therefore, when the granules are fed into the hopper of the injection molding machine, bridging sometimes occurs, preventing them from falling stably into the rollers and screw.

[0072] When the nozzle flow path length is greater than 150mm, the resin pressure increases, which can sometimes affect productivity.

[0073] (2) The area (S1) of the minimum cross-sectional area of ​​the opening in the base is 6 mm.2 Above 80mm 2 the following.

[0074] The area (S1) of the minimum cross-sectional area of ​​the opening 16 of the base 13, described later, is 6 mm². 2 Above 80mm 2 The following is preferred: 10mm 2 The above 60mm 2 The following is more preferably 12mm 2 Above 50mm 2 From the viewpoint of granule shape, it is preferable that the area (S1) of the minimum cross-sectional area of ​​the opening 16 of the base 13 is within the range described above.

[0075] The opening 16 formed in the base 13 is sometimes like Figure 2 The diagram shows a straight line shape with the same diameter from the inlet to the outlet. In this case, the aperture of opening 16 can be the same as that of opening outlet 16B, and the aperture of opening 16 from opening inlet 16A to opening outlet 16B becomes the diameter of the smallest cross-sectional area portion of opening 16.

[0076] Additionally, the opening 16 formed in the base 13 sometimes appears as... Figure 12 The diagram shows an opening 16 with an upstream side that is a straight line shape of the same diameter and a downstream side that gradually widens towards the nozzle die 14. In this case, the diameter of the smallest cross-sectional area portion of the opening 16 (e.g., the diameter of the starting portion of the cone) is used as the aperture of the opening 16.

[0077] In this invention, the cone shape is typically a shape to the extent that the corner portion of the opening 16 is chamfered. Furthermore, the distance from the starting portion of the cone to the opening outlet 16B is also typically the distance required for the aforementioned chamfering.

[0078] (3) The nozzle outlet area (S0) is 3 mm. 2 Above 20mm 2 the following.

[0079] Regarding the area (S0) of nozzle outlet 11, in Figures 1-3 In the nozzle 9 shown, is Figure 5 and Figure 3 The area of ​​nozzle outlet 11 shown.

[0080] The area (S0) of nozzle outlet 11 is 3 mm. 2 Above 20mm 2 The following is preferred: 4mm 2 Above 15mm 2 The following is more preferably 5mm 2 Above 10mm 2From the viewpoint of particle shape, it is preferable that the area (S0) of the nozzle outlet 11 is within the range described above.

[0081] (4) The relationship S1≥S0 holds true.

[0082] In the nozzle die and base used in the manufacturing method and apparatus for manufacturing resin granules containing reinforcing fibers of the present invention, the area (S0) of the nozzle outlet 11 is smaller than or equal to the area (S1) of the smallest cross-sectional area portion of the opening 16 of the base 13. From the viewpoint of discharge volume and granule shape, it is preferable that the relationship S1 ≥ S0 holds.

[0083] In the nozzle die 14 used in the manufacturing method and manufacturing apparatus for the resin granules containing reinforcing fibers of the present invention, the cross-sectional area of ​​the nozzle from the nozzle inlet 10 to the nozzle outlet 11 remains unchanged, or the cross-sectional area of ​​the nozzle from the nozzle inlet 10 toward the nozzle outlet 11 decreases.

[0084] Figures 1-3 The nozzle 9 shown has a parallel part 9b and a conical part 9a, so the relationship S1 > S0 holds true.

[0085] Furthermore, when the area of ​​the nozzle 9 formed by the nozzle die head 14 and the nozzle inlet 10 is defined as S2, it is preferable that S2 is 6mm. 2 Above 80mm 2 the following.

[0086] The nozzle 9 formed by the nozzle die 14 used in this invention is not particularly limited. Specifically, a nozzle of the same shape and size as that described in Japanese Patent Application Publication No. 2022-154027 can be used. For example, from Embodiment 1 of that publication (L1 = 125 mm, L2 = 85 mm, S2 = 20 mm) 2 S0 = 7mm 2 Example 2 (L1 = 125mm, L2 = 125mm, S2 = 20mm) 2 S0 = 20mm 2 Example 4 (L1 = 65mm, L2 = 65mm, S2 = 20mm) 2 S0 = 20mm 2 Example 5 (L1 = 125mm, L2 = 0mm, S2 = 20mm) 2 S0 = 7mm 2 Choosing from options such as () is also the preferred method.

[0087] The nozzle 9 used in the manufacturing method and apparatus for the resin granules containing reinforcing fibers of the present invention preferably has both a parallel portion and a conical portion, but it is not necessary to have both a parallel portion 9b and a conical portion 9a; it can also be as follows: Figure 4 Like the nozzle 9A of the nozzle die head 14A shown, it does not have a tapered portion but only a parallel portion 9bA; it can also be like... Figure 5 Like the nozzle 9B of the nozzle die 14B shown, it does not have a parallel portion but only a tapered portion 9aB. When the nozzle 9 only has a parallel portion, L1 = L2.

[0088] Furthermore, regarding the nozzle used in the manufacturing method and apparatus for the resin granules containing reinforcing fibers of the present invention, the width of the nozzle die 14 is 94 mm or more, with no particular upper limit. Preferably, the width of the nozzle die 14 is 94 mm to 665 mm, more preferably 230 mm to 600 mm. By setting it within this range, excellent results can be obtained in terms of granule stability.

[0089] Regarding the width of the nozzle die 14, for example in Figure 1 , 2 The nozzle die 14 described refers to the dimension in the depth direction of the paper surface.

[0090] The number of nozzles 9 arranged inside the nozzle die head 14 is 5 to 70, preferably the nozzle outlets 11 are arranged in a row in the horizontal direction, or as follows: Figure 13 The nozzle outlets 11 shown are arranged in two rows, one above the other, and staggered.

[0091] Interleaved configuration refers to, for example Figure 13 As shown, the openings are arranged in two rows, staggered from each other. Furthermore, with two rows of openings, the openings in the upper row do not touch the openings in the lower row. Also, when viewed vertically, the openings in the upper and lower rows typically do not overlap. Additionally, the lower row usually has one more opening than the upper row.

[0092] In the case of staggered arrangement, the distance between the upper and lower open rows is preferably 6 mm or more, 6 to 20 mm, and more preferably 7 to 15 mm. The distance referred to here is the distance between the straight lines passing through the centers of the openings of each row.

[0093] That is, as a premise of the invention, even if a long die head with a long die head is used as the nozzle die head 14 as shown in Patent Document 4, there is still a problem of unstable material strands when using a medium- or large-scale manufacturing apparatus for reinforced fiber resin granules with a wide die head. Therefore, a necessary premise is that the nozzle die head 14 is a medium- or large-scale long die head.

[0094] Furthermore, regarding the relationship between the width of the nozzle die 14 and the number of openings 16 in the base 13, when the width of the nozzle die 14 is 94mm to 665mm, it is preferable that the number of openings 16 is approximately 5 to 70; when the width of the nozzle die 14 is 230mm to 600mm, it is preferable that the number of openings 16 is approximately 14 to 40.

[0095] Furthermore, the nozzle die 14 and base 13 used in the manufacturing method and manufacturing apparatus for the resin granules containing reinforced fibers of the present invention also satisfy the following requirements (5) to (8), preferably (5) to (9).

[0096] (5) In the openings formed by the above-mentioned base, the proportion of the number of non-standard aperture openings at both ends is less than 20% of the total number.

[0097] The standard aperture refers to the average aperture of a portion of the multiple openings formed in a row in the base 13. Specifically, the standard aperture represents the average diameter of the openings excluding the following (α) and (β) from the openings formed in the base.

[0098] (α) The number of openings formed in the openings at both ends of the base is less than 20% of the total number of openings.

[0099] (β) An opening formed in the central part of the base, comprising less than 20% of the total number of openings.

[0100] The reason why it is defined as the average diameter of the apertures after excluding (α) and (β) is to take into account that the diameters of the apertures after excluding (α) and (β) may also have deviations, and an averaging process is performed. In addition, the cross-sectional area of ​​the aperture 16 used to calculate the standard aperture is preferably within ±5% of the average cross-sectional area of ​​all the apertures formed by the base 13. Furthermore, the cross-section of the aperture 16 formed by the base 13 is circular in principle.

[0101] Furthermore, as mentioned above, regarding the aperture of opening 16, in such cases... Figure 2 When the opening 16 formed by the base 13 shown has a straight-line shape, the aperture of the opening outlet 16B can be used as the aperture of the opening 16. On the other hand, in cases such as Figure 12 When the upstream side of the opening 16 is in a straight line shape and a portion of the downstream side is in a conical shape, the aperture of the smallest cross-sectional area portion of the opening 16 and the portion closest to the nozzle die head 14 is taken as the aperture of the opening 16.

[0102] Furthermore, regarding the exclusion condition shown in (α) above, the number of openings formed on both ends of the base is set to be equal. Specifically, "less than 20% of the total number of openings" means that all openings 16 formed on one end of the base 13 account for less than 10% of the total number of openings, and all openings 16 formed on the other end account for less than 10% of the total number of openings.

[0103] Here, the ratio of the number of openings at both ends of a non-standard aperture refers to the ratio of the number of openings at both ends of the non-standard aperture to the total number of openings formed on the base. For example, as... Figure 9 As shown in the E-type base opening diagram, with a total of 40 base openings and 2 openings at each end of the base, the aforementioned ratio is 10%. In this way, by adjusting the diameter of the openings at both ends of the base, the flow rate of the nozzles at both ends can be suppressed due to the shear flow characteristic of fibrous materials, and the loosening of the strands at both ends can be reduced.

[0104] Furthermore, among the openings formed at both ends of the base, it is preferable that the ratio of the number of openings on the side with the non-standard aperture is equal to the ratio of the number of openings on the other side with the non-standard aperture.

[0105] In addition, regarding the proportion of the number of non-standard aperture openings, it is preferable that the proportion of the number of non-standard aperture openings formed on one side of the base is less than 10% of the total number of openings, and the proportion of the number of non-standard aperture openings formed on the other side of the base is also less than 10% of the total number of openings.

[0106] (6) In the opening formed by the base described above, the ratio of the diameter of the non-standard aperture openings at both ends to the standard aperture is in the range of 50% to 98%. That is, according to (5) and (6), it is preferable that there must be one non-standard aperture opening at each end of the base.

[0107] The ratio of the diameter of the opening at both ends to the standard diameter is the ratio of the diameter of the opening at both ends to the standard diameter of the opening.

[0108] (7) In the openings formed by the above-mentioned base, the proportion of the number of non-standard diameter central openings is less than 20% of the total number.

[0109] This ratio is the number of non-standard orifice openings in the central section divided by the total number of openings formed by the base. Especially in large-scale nozzle dies 14, since the flow rate in the central section is reduced, by making the orifice diameter in the central section non-standard, the flow rate is suppressed, and the relaxation of the central material strand can be reduced.

[0110] (8) In the opening formed by the base described above, the ratio of the diameter of the central opening to the standard diameter is between 70% and 100%.

[0111] That is, according to (7) and (8), in the central opening, there is sometimes not even one non-standard aperture opening.

[0112] (9) In the openings formed by the base, when there are multiple non-standard aperture openings, the cross-sectional area of ​​the outermost (end) opening is less than the cross-sectional area of ​​the non-standard aperture opening that is not located at the outermost (end) opening and is less than the cross-sectional area of ​​the standard aperture opening.

[0113] That is, in medium- and large-scale nozzle dies 14, the flow rate of the outermost nozzle increases due to the shear flow characteristic of the fibrous material. Therefore, in order to stabilize the stock, it is preferable to reduce the cross-sectional area of ​​the opening 16 of the base 13 located at the outermost (end) and the cross-sectional area of ​​the opening 16 of the base 13 within the scope specified in this invention.

[0114] Furthermore, from the perspective of flow balance, it is preferable that the flow distribution in the right and left halves of the die head is equal, with the center of the die head as the boundary. Specifically, it is preferable that the cross-sectional area and flow rate of the openings that are linearly symmetrical with the center of the die head as the boundary are equal.

[0115] The method for manufacturing resin granules containing reinforcing fibers according to the present invention includes: a step of supplying resin into a twin-screw extruder from a position closer to the inlet side than the first mixing section, and performing melt mixing of the resin in the first mixing section (step 1); a step of supplying reinforcing fibers into the twin-screw extruder from a position closer to the outlet side than the first mixing section and closer to the inlet side than the aforementioned second mixing section, and performing further melt mixing of the resin in the presence of the reinforcing fibers (step 2); and a step of extruding the melt-mixed resin containing reinforcing fibers from the nozzle outlet of the die head in the form of a strand of resin containing reinforcing fibers (step 3).

[0116] Below, with Figures 1-3 Taking the twin-screw extruder 1 and die head 2 shown as examples, the above processes 1 to 3 will be explained.

[0117] In step 1, resin is supplied from the resin supply section 7 to the inner bore of the barrel 3 of the twin-screw extruder 1. The supplied resin moves within the barrel 3 due to the action of the screw 4 and is conveyed to the first mixing section 5. Before reaching the first mixing section 5, the screw 4 is constructed, for example, as a fully threaded screw. The resin conveyed to the first mixing section 5 is melt-mixed in the first mixing section 5.

[0118] In this invention, the mixing section refers to a part in a twin-screw extruder that functions to melt and homogenize materials. The mixing section of this invention includes not only parts that mix, melt, and homogenize two or more materials, but also parts that, in the case of a single material, mix, melt, and homogenize to achieve uniform physical properties. The mixing section of this invention is, for example, a part where the screw structure is a kneading disc rather than a fully threaded screw.

[0119] The resin used in the manufacturing method and apparatus for the resin granules containing reinforcing fibers of the present invention is a propylene-based polymer. The propylene-based polymer is either a propylene homopolymer or a propylene copolymer. In the case of a propylene copolymer, the content of structural units derived from propylene is preferably 40 mol% or more, more preferably 50 mol% or more. Examples of monoolefins that serve as structural units derived from monomers other than propylene include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 2-methyl-1-propylene, 3-methyl-1-pentene, 4-methyl-1-pentene, and 5-methyl-1-hexene, with ethylene and 1-butene being more preferred. The polymerization method can be either atactic or block copolymer. Among these resins, propylene homopolymers, propylene-ethylene block copolymers, propylene-ethylene random copolymers, and propylene-ethylene-butene random copolymers are preferred, with propylene homopolymers being more preferred. As the aforementioned propylene-based polymer, any type—isotactic, syndiotactic, or atactic—is acceptable, with isotactic propylene being preferred. That is, the resin used in the method and apparatus for manufacturing the fiber-reinforced resin granules of the present invention is particularly preferably an isotactic propylene homopolymer. These polymers can be used alone or in combination of two or more.

[0120] The melt flow rate of the aforementioned propylene polymer at 230°C and a load of 2.16 kg is 20–500 g / 10 min, preferably 30–200 g / 10 min, and more preferably 30–150 g / min. When the melt flow rate of the propylene polymer is within the above range, the melt viscosity of the resin decreases, so the reinforcing fibers are less likely to be sheared in the twin-screw extruder, thus suppressing the breakage of the reinforcing fibers, which is preferred in this respect.

[0121] In step 2, reinforcing fibers are supplied from the fiber supply section 8 to the inner bore of the barrel 3 of the twin-screw extruder 1. The supplied reinforcing fibers are mixed with the melt-mixed resin transported from the first mixing section 5, and moved within the barrel 3 by the action of the screw 4, and then conveyed to the second mixing section 6. From the first mixing section 5 to the second mixing section 6, the screw 4 is constructed, for example, as a fully threaded screw. The resin mixed with reinforcing fibers, transported to the second mixing section 6, is further melt-mixed in the second mixing section 6.

[0122] As for the aforementioned reinforcing fibers, there are no particular limitations on any material that can be commonly used for resin reinforcement; glass fibers, carbon fibers, metal fibers, and organic fibers (polyamide, polyester, aramid, polyphenylene sulfide, liquid crystal polymers, acrylics, etc.) can be used. Among these, glass fibers and carbon fibers are particularly preferred. As for glass fibers, commonly used E-glass or high-strength, high-elastic-modulus T-glass are preferred.

[0123] The reinforcing fiber has a fiber length of 2.5 mm to 8 mm, preferably 3 mm to 7 mm, and more preferably 3 mm to 6 mm. From a productivity point of view, the fiber length of the reinforcing fiber is preferably within the above range.

[0124] The reinforcing fiber has a diameter of 5 μm or more and less than 17 μm, preferably 10 μm or more and less than 17 μm, and more preferably 10 μm or more and less than 13 μm. From the viewpoint of mechanical properties, it is preferable that the reinforcing fiber diameter is within the above range.

[0125] There is no particular limitation on the number of reinforcing fibers in a bundle, but bundling 10 to 20,000 single fibers or filaments is preferred due to its good operability. Generally, to improve interfacial adhesion with the resin, the reinforcing fibers can also be used after surface treatment with a silane coupling agent or similar agent.

[0126] As for the ratio of the above-mentioned resin to the reinforcing fiber supplied, it is preferable to contain 5% to 50% by mass of the reinforcing fiber, preferably 15% to 50% by mass, more preferably 25% to 45% by mass, and to contain 50% to 95% by mass of the resin, preferably 50% to 85% by mass, more preferably 55% to 75% by mass (the total of the reinforcing fiber and the resin is 100% by mass).

[0127] As described above, the second mixing section 6 has a notched reverse conveying screw element and / or includes a reverse conveying kneading disc. A notched reverse conveying screw element is preferred for further increasing the residual fiber length, etc. When the second mixing section 6 has a reverse conveying screw element, mixing and dispersion performance can be improved, energy consumption is reduced, thermal efficiency is improved, the melting temperature of the synthetic resin raw material can be suppressed to a lower level, glass fibers are less prone to breakage, and the properties of the raw material are easily ensured.

[0128] As a reverse feed screw element, it is preferable to have a screw element with multiple notches formed at the tip of the thread of the screw. The reverse feed screw element is preferably configured as a single-start or double-start screw in the reverse direction. Preferably, the lead of the aforementioned reverse feed screw element is configured to be 0.15×D to 1.0×D (D: screw diameter). Preferably, 2 to 30 notches are formed within one lead of the aforementioned reverse feed screw element, and they can be parallel to the screw axis or twisted in any direction. Preferably, the reverse feed screw element is a single-start thread with L / D (screw length / screw diameter) = 1, has notches, and a lead of 0.25D to 0.5D. A specific example is BMS manufactured by Nippon Steel Corporation. By using a reverse feed screw element with notches, the reinforcing fibers are almost never broken, the reinforcing fibers in the resin are long, and the fiber opening properties are good, allowing for uniform dispersion in the molten resin.

[0129] Including reverse conveying kneading discs, for example Figure 6 The structure shown can be achieved using a commercially available kneading disc.

[0130] In step 3, the resin with long reinforcing fibers obtained in step 2 is supplied from outlet B of the twin-screw extruder 1 to resin flow path inlet 20. The supplied resin flows into the support space 15, and while the flow path is narrowed within the die holder 12, it spreads rapidly in the lateral width direction and is supplied to the base 13. At this time, because the resin is oriented along the wall, due to the shear flow characteristic of the fiber-based material, the flow rate at the openings 16 at both ends is greater than that at the opening 16 closer to the center.

[0131] The resin within the base 13 is supplied to each nozzle 9 through outlets of multiple openings 16, i.e., nozzle inlets 10. The resin containing reinforcing fibers, after melt mixing, is extruded from the nozzle outlet 11 of the die head 2 as a strand containing reinforcing fiber resin. From the second mixing section 6 to the die head 2, the screw 4 is constructed, for example, as a fully threaded screw.

[0132] The base and nozzle used in process 3 meet the following (1) to (8).

[0133] (1) The nozzle flow path length is more than 60mm and less than 150mm.

[0134] (2) The cross-sectional area (S1) of the minimum cross-sectional area of ​​the opening of the base is 6 mm. 2 Above 80mm 2 the following.

[0135] (3) The cross-sectional area (S0) of the nozzle outlet is 3 mm. 2 Above 20mm 2 the following.

[0136] (4) The relationship S1≥S0 holds true.

[0137] (5) In the openings formed by the above-mentioned base, the proportion of the number of non-standard aperture openings at both ends is less than 20% of the total number.

[0138] (6) In the opening formed by the above-mentioned base, the ratio of the diameter of the opening at both ends to the standard diameter is between 50% and 98%.

[0139] (7) In the openings formed by the above-mentioned base, the proportion of the number of non-standard diameter central openings is less than 20% of the total number.

[0140] (8) In the opening formed by the base described above, the ratio of the diameter of the central opening to the standard diameter is between 70% and 100%.

[0141] Furthermore, the base used in step 3 preferably satisfies the following (9).

[0142] (9) In the openings formed by the base, when there are multiple non-standard aperture openings, the cross-sectional area of ​​the outermost (end) opening is less than the cross-sectional area of ​​the non-standard aperture opening that is not located at the outermost (end) opening and is less than the cross-sectional area of ​​the standard aperture opening.

[0143] By using the nozzle in step 3, even if the reinforcing fibers in the resin are long, they will not fly out of the granules, enabling continuous production. Since the reinforcing fibers also do not fly out of the resulting granules, bridging will not occur in the hopper of the injection molding machine during injection molding, ensuring stable injection molding.

[0144] The screw speed of the twin-screw extruder in steps 1 to 3 is preferably above 250 rpm and below 800 rpm.

[0145] From the viewpoint of extending the length of residual glass fibers and preventing resin thermal degradation, the set temperature of the twin-screw extruder from the first mixing section to the nozzle in steps 1 to 3 is preferably 230°C or higher and 290°C or lower, more preferably 240°C or higher and 290°C or lower.

[0146] In the method for manufacturing resin granules containing reinforcing fibers according to the present invention, the strand of resin containing reinforcing fibers obtained through the above-described steps 1 to 3 is granulated using a known method, thereby obtaining resin granules containing reinforcing fibers. As for granulation, it is preferable, for example, as disclosed in Japanese Patent Publication No. 41-20738, to cool the strand and granulate it using a cutting machine, or to cut it to a predetermined size immediately after extrusion from the die.

[0147] The shape and size of the resin granules containing reinforcing fibers obtained by the manufacturing method and apparatus of the present invention are not particularly limited. For example, the length of the resin granules containing reinforcing fibers in the elongation direction of the granules can be set to 3 mm or more and 10 mm or less. When the length is less than 3 mm, the length of the residual fibers in the granules becomes shorter, and sometimes the required strength cannot be exhibited. When the length exceeds 10 mm, the metering during injection molding becomes unstable, and sometimes it can cause obstacles to the molding cycle.

[0148] The resin granules containing reinforcing fibers produced by the manufacturing method and apparatus of the present invention contain 5% to 50% by mass of reinforcing fibers, preferably 15% to 50% by mass, more preferably 25% to 45% by mass, and contain 50% to 95% by mass of resin, preferably 50% to 85% by mass, more preferably 55% to 75% by mass (the total of reinforcing fibers and resin is 100% by mass). In the manufacturing method of the resin granules containing reinforcing fibers of the present invention, the supply amounts of reinforcing fibers and resin in the above-described steps 1 and 2 are determined so that the ratio of reinforcing fibers to resin in the resin granules containing reinforcing fibers is within the above-described range.

[0149] The resin granules containing reinforcing fibers produced by the method and apparatus of the present invention have reinforcing fibers (residual fibers) whose fiber length is shorter than the granule length, for example, 1.5 mm to 8 mm or 1.5 mm to 3.0 mm. Using the method and apparatus of the present invention, resin granules containing reinforcing fibers with short fibers can be manufactured as described above. The resin granules containing reinforcing fibers produced by the method and apparatus of the present invention are characterized in that, even when containing short fibers, they possess the same mechanical properties as resin granules containing long fibers. The reason why resin granules containing reinforcing fibers with the same mechanical properties as those containing long fibers can be manufactured using the method and apparatus of the present invention, even when containing short fibers, is presumably due to the long residual fibers in the granules, which exhibit excellent mechanical strength.

[0150] In the resin granules containing reinforcing fibers produced by the manufacturing method and apparatus of the present invention, in order to impart the desired properties, known substances commonly used in thermoplastic resins can be added, such as antioxidants, heat stabilizers, UV absorbers, and other known stabilizers, antistatic agents, flame retardants, flame retardant additives, colorants such as dyes or pigments, lubricants, plasticizers, crystallization promoters, and crystallization nucleating agents. Furthermore, inorganic fillers such as glass sheets, glass powder, glass beads, silica, montmorillonite, quartz, talc, clay, alumina, carbon black, wollastonite, mica, calcium carbonate, and metal powders can also be added simultaneously.

[0151] The resin granules containing reinforcing fibers produced by the manufacturing method and apparatus of the present invention can be molded using known molding methods such as injection molding, injection compression molding, extrusion molding of tubes, pipes, or sheets, and blow molding. During molding, to suppress breakage of the reinforcing fibers, it is preferable to enlarge the nozzle or gate shape so that the groove depth of the molding machine screw is greater than the granule size.

[0152] According to the present invention, a method and apparatus for manufacturing resin granules containing reinforcing fibers are provided. When manufacturing granules containing reinforcing fibers with long fiber lengths, even when using a die with a wide width and long die length, the granules can be stabilized, the molded body has an excellent appearance, and it can exhibit excellent mechanical properties.

[0153] Example The methods for determining physical properties in the examples and comparative examples are as follows.

[0154] (Mel flow rate (MFR)) The melt flow rate was determined according to ISO 1133 at a temperature of 230°C and a load of 2.16 kg.

[0155] (Residual fiber length) 1g of granules was ashed at 600℃ for 75 minutes. The ashed sample was photographed using a microscope, and the length of more than 1000 fibers was measured using image processing software. The average length of the measured fiber was taken as the length of the remaining fibers.

[0156] (Glass fiber (GF) flies out from the die head exit) The ejection of glass fiber at the die exit point is evaluated visually according to the following criteria.

[0157] None: No glass fiber was observed flying out.

[0158] Slightly: Glass fibers were occasionally observed flying out.

[0159] Yes: Glass fibers were consistently observed flying out.

[0160] (Continuous productivity) The condition of the strands is judged by visually comparing the state of the strands in the center and at the end of the die head. A case of observed strand looseness is rated as ×, and a case of no observed looseness is rated as 0.

[0161] [Example 1] Twin-screw extruders use a Figure 1 The TEX65 extruder (15 barrels) manufactured by Nippon Steel Corporation is shown in the diagram. Hereinafter, each barrel will be designated C1, C2, C3, ..., C13, C14, C15 from the upstream side of the extruder. The resin supply section is located at C1, and the fiber supply section is located at C11. The set temperature is set as follows: C1 / C2 / C3 / C4 / C5 / C6 / C7 / C8 / C9 / C10 / C11 / C12 / C13 / C14 / C15 = Water cooling / 100℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃.

[0162] In the second mixing section, a notched reverse conveying screw element was assembled, consisting of a... Figure 7 The structure shown is that of a BMS manufactured by Nippon Steel Corporation.

[0163] Figure 8 The table shows the parameters and evaluation results of Examples 1-4 and Comparative Example 1.

[0164] The screw speed is set to 330 rpm. The outlet section of the aforementioned twin-screw extruder is equipped with... Figure 12 The nozzle die and base are shown in the diagram. The nozzle die has a nozzle with a circular cross-section, which has a parallel section and a conical section. The nozzle flow path length (L1) is 125 mm, and the parallel flow path length (L2) is 85 mm. The nozzle outlet configuration of the nozzle die is not staggered, but rather a linear configuration in which the nozzles are arranged in a row. The total number of nozzles is 40.

[0165] Furthermore, part of the opening of the base is a conical type, with the upstream side of the opening being in a straight line shape and the downstream side having a tapered shape. The tapering is formed by chamfering the corners of the opening. In the above-described nozzle die, the area (S2) of the nozzle inlet is 20 mm². 2 The nozzle outlet area (S0) is 7 mm. 2 The die head temperature is set to 280℃.

[0166] On the base of the nozzle die head, such as Figure 9As shown in (a) and (b), the base opening type B has 40 openings numbered No. 1 to 40 in a horizontal row. The cross-section of the opening is circular. In this embodiment 1, in addition to the 6 nozzles on both ends and the 6 nozzles on the central side as shown below, each opening has a diameter of 20mm. 2 The minimum cross-sectional area. Furthermore, due to the relatively long lateral width of the base (600mm), therefore... Figure 9 Divided into Figure 9 The presentation is divided into two parts, (a) and (b).

[0167] The openings (No. 1–3, 38–40, 18–23) are a portion of the downstream side with a conical shape. The openings at both ends (No. 1–3, No. 38–40) have a diameter of 14 mm. 2 The minimum cross-sectional area. Furthermore, the base openings (No. 18–23) on the central side have a diameter of 18 mm. 2 The minimum cross-sectional area.

[0168] Furthermore, the other openings (No. 4-17, No. 24-37) are inline openings with the same diameter from the inlet to the outlet, and have a diameter of 20mm. 2 The minimum cross-sectional area.

[0169] In addition, the base section is constructed such that resin flows from each opening outlet of the base to the corresponding nozzle inlet.

[0170] The apertures used as the calculation objects for the standard apertures are the apertures of No.5 to No.16 and No.25 to No.36, excluding the 20% of the apertures at both ends (No.1 to 4, 37 to 40) and the 20% of the apertures in the center (No.17 to 20, 21 to 24).

[0171] Of the 40 openings in total, the proportion of non-standard diameter end openings is 15% (6 / 40), and the proportion of the diameter at both ends to the standard diameter is 85%.

[0172] In addition, compared to all 40 openings, the proportion of non-standard diameter central openings is 15% (6 / 40), and the proportion of central opening diameter to standard diameter is 95%.

[0173] In addition, at the nozzle outlet, the flow rate ratio of the two end holes is 121%, the flow rate ratio of the end three holes is 94%, and the flow rate ratio of the central hole is 93%.

[0174] Here, the flow rate ratio refers to the ratio of the output per unit time at the nozzle outlet to the standard output (described later). For example, the flow rate ratio of the two end orifices is the value obtained by dividing the output per unit time of end orifice by the standard output. The flow rate ratio of the central orifice is calculated in the same way. In addition, the flow rate ratio of the three end orifices is the value obtained by dividing the average output per unit time of the three end orifices by the standard output.

[0175] In addition, the production per unit time can be calculated by actually measuring the flow rate flowing out of the nozzle outlet of the target. The standard production rate represents the average flow rate per orifice, which is calculated by dividing the total flow rate per unit time, calculated based on the raw material supply per unit time, by the total number of nozzle outlets.

[0176] Using a gravimetric feeder, a mixture of Prime Polypro (MFR: 210 g / 10 min), Prime Polypro (MFR: 30 g / 10 min), and Polybond 3200 (manufactured by Addivant) in a 60 / 10 / 1 mass ratio was supplied from the resin supply section of the twin-screw extruder at a rate of 395 kg / h. 4000 monofilaments of glass fiber (manufactured by Nippon Electric Glass Co., Ltd., 3T-480H, fiber diameter: 10 μm) were bundled and cut into 3 mm lengths, and the cut fibers were supplied from the fiber supply section at a rate of 165 kg / h. The twin-screw extruder was operated under the above conditions, and the molten compound was extruded from the nozzle outlet as a strand containing the reinforcing fiber resin.

[0177] The obtained strands were granulated using a cutting machine to obtain resin granules containing reinforcing fibers with a length of 3 mm. The production rate of these granules was 560 kg / h, and the glass fiber content in the granules was 30% by mass.

[0178] According to Example 1, the strands at both ends are not loose, and the strands can be continuously pulled out, thus achieving stable granulation.

[0179] [Example 2] The apertures of holes No. 18 to 23 in the central opening of Example 1, and the apertures of holes No. 2, 3, 38, and 39 in the end openings, are changed to standard apertures. Furthermore, the minimum cross-sectional area of ​​the base openings No. 1 and 40 in the end base openings is changed to 17 mm². 2 Otherwise, the process was carried out in the same manner as in Example 1 to obtain granules ( Figure 9 (Base opening type C). Base openings No. 1 and 40 are conical openings, while the other openings are in a straight line.

[0180] Of the 40 openings in total, the proportion of non-standard diameter end openings is 5% (2 / 40), and the proportion of openings at both ends to the standard diameter is 92%.

[0181] In addition, relative to all 40 nozzles, the proportion of non-standard orifice diameter central openings is 0% (0 / 40), and the proportion of central opening diameters relative to standard orifice diameters is 100%.

[0182] Here, the flow rate ratio of the two end holes at the nozzle outlet is 132%, and the flow rate ratio of the three central holes is 109%. Furthermore, the flow rate ratio of the two end holes is 93%.

[0183] According to Example 2, the strands at both ends are not loose, and the strands can be continuously pulled out, thus achieving stable granulation.

[0184] [Example 3] The apertures of the openings at No.1 and 40 at the ends in Example 2 were changed, and the apertures of the openings at No.2 and 39 were also changed. Otherwise, the process was the same as in Example 2 to obtain granules.

[0185] The openings at both ends (No.1, No.40) have non-standard apertures and are 16mm in diameter. 2 The minimum cross-sectional area; the openings (No.2, No.39) are non-standard apertures and have an 18mm diameter. 2 The minimum cross-sectional area. All other openings (No. 3 to 38) are standard apertures and have a diameter of 20 mm. 2 Minimum cross-sectional area ( Figure 9 (Base opening type D).

[0186] Of the 40 openings, the proportion of non-standard diameter end openings is 10% (4 / 40), while the proportion of both ends relative to standard diameters is 90%. Among them, base openings No. 1, 2, 39, and 40 are tapered openings, while the other openings are inline openings.

[0187] Here, the flow rate ratio of the two end holes at the nozzle outlet is 107%, and the flow rate ratio of the three central holes is 101%. Furthermore, the flow rate ratio of the two end holes is 93%.

[0188] According to Example 3, the strands at both ends are not loose, and the strands can be continuously pulled out, thus achieving stable granulation.

[0189] [Example 4] The apertures of the openings at No.1 and 40 at the ends in Example 2 were changed, and the apertures of the openings at No.2 and 39 were also changed. Otherwise, the process was the same as in Example 2 to obtain granules.

[0190] The openings on both sides (No.1, No.40) are non-standard apertures and have a diameter of 14mm. 2 The minimum cross-sectional area; the openings (No.2, No.39) are non-standard apertures and have a diameter of 16mm. 2 The minimum cross-sectional area. Furthermore, openings (No. 1, 2, 39, 40) are tapered. Additionally, the other openings (No. 3–38) are inline openings with a standard aperture and a diameter of 20 mm. 2 Minimum cross-sectional area ( Figure 9 (Base opening type E).

[0191] Compared to all 40 openings, the proportion of non-standard aperture end openings is 10% (4 / 40), and the proportion of openings at both ends relative to standard apertures is 85%.

[0192] Here, the flow rate ratio of the one orifice at each end is 118%, and the flow rate ratio of the three orifices in the central part is 104%. Furthermore, the flow rate ratio of the one orifice at each end is 93%.

[0193] According to Example 4, the strands at both ends are not loose, and the strands can be continuously pulled out, thus achieving stable granulation.

[0194] [Comparative Example 1] Change the aperture of all openings in Example 2 to the standard aperture ( Figure 9 The base opening is type A. Otherwise, the process is the same as in Example 2 to obtain granules. In this example, all the base openings are in a straight line.

[0195] Here, the flow rate ratio of the two end holes is 143%, and the flow rate ratio of the three central holes is 112%. Furthermore, the flow rate ratio of the two end holes is 93%.

[0196] In Comparative Example 1, such as Figure 14 As shown, the material at both ends flexes, resulting in a problem that cannot ensure continuous production.

[0197] [Example 5] Figure 10 The table shows the parameters and evaluation results for Examples 5-7 and Comparative Example 2. The openings of the bases in all these examples and comparative examples are in a straight line.

[0198] Twin-screw extruders use a Figure 1The TEX44 (15 barrel blocks) manufactured by Nippon Steel Corporation is shown in the diagram. Hereinafter, each barrel block will be designated C1, C2, C3, ..., C13, C14, C15 from the upstream side of the extruder. The resin supply section is located at C1, and the fiber supply section is located at C11. The set temperature is set as follows: C1 / C2 / C3 / C4 / C5 / C6 / C7 / C8 / C9 / C10 / C11 / C12 / C13 / C14 / C15 = Water cooling / 100℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃ / 260℃.

[0199] In the second mixing section, a notched reverse conveying screw element was assembled, consisting of a... Figure 7 The BMS shown is manufactured by Nippon Steel Corporation. The screw speed is set to 350 rpm.

[0200] The outlet of the aforementioned twin-screw extruder is equipped with a... Figure 2 The die head has the shape shown. The nozzle die head has a nozzle with a circular cross-section, which has a parallel section and a tapered section. The nozzle flow path length (L1) is 125 mm, and the parallel flow path length (L2) is 85 mm. Additionally, the area (S1) of the opening in the base is 7–20 mm². 2 The area (S0) of the nozzle outlet in the nozzle die head is 7 mm. 2 The die head temperature is set to 280℃. The number of nozzles is 14.

[0201] In the base, such as Figure 11 As shown in type B, the base has 14 openings numbered No. 1 to 14 in a horizontal row. The openings are circular, and the horizontal width of the base is 230 mm.

[0202] The openings at both ends of the base (No.1, No.14) are 7mm. 2 The cross-sectional area. Furthermore, the two central openings (No. 7, No. 8) have a diameter of 12.6 mm. 2 The minimum cross-sectional area. In addition, other openings have a 20mm... 2 The minimum cross-sectional area.

[0203] In the base, the openings used as the calculation objects for the standard orifice diameter are those No. 2 to 6 and No. 9 to 13, excluding the openings at both ends (No. 1, No. 14) and the openings at the center (No. 7, No. 8). No. 1, 7, 8, and 14 have non-standard orifice diameters. Furthermore, the base portion has a structure that allows resin to flow from the outlet of each opening in the base to the inlet of each corresponding nozzle.

[0204] Compared to all 14 openings, the proportion of non-standard aperture end openings is 14% (2 / 14), and the proportion of apertures at both ends relative to standard apertures is 60%.

[0205] In addition, compared to all 14 openings, the proportion of non-standard aperture central openings is 14% (2 / 14), and the proportion of central openings relative to standard apertures is 80%. All openings are in line.

[0206] Here, at the nozzle outlet, the flow rate ratio of the two-end one-hole is 74%, and the flow rate ratio of the two-end one-hole is 93%.

[0207] Using a gravimetric feeder, a mixture of Prime Polypro (MFR: 210 g / 10 min), Prime Polypro (MFR: 30 g / 10 min), and Polybond 3200 (manufactured by Addivant) in a 60 / 10 / 1 mass ratio was supplied from the resin supply section of the twin-screw extruder at a rate of 140 kg / h. 4000 monofilaments of glass fiber (manufactured by Nippon Electric Glass Co., Ltd., 6T-480H, fiber diameter: 10 μm) were bundled and cut into 6 mm lengths, and the cut fibers were supplied from the fiber supply section at a rate of 60 kg / h. The twin-screw extruder was operated under the above conditions, and the molten compound was extruded from the nozzle outlet as a strand of resin containing reinforcing fibers.

[0208] According to Example 5, the strands at both ends are not loose, and the strands can be continuously pulled out, thus achieving stable granulation.

[0209] [Example 6] In Example 5, the apertures of openings No. 1 and 14 at the ends of the base, and the apertures of openings No. 7 and 8 in the central opening, were changed. Otherwise, the process was the same as in Example 5 to obtain granules. Here, the openings at both ends (No. 1 and 14) have a diameter of 12.6 mm. 2 The minimum cross-sectional area, the opening in the central part (No. 7, 8) has a diameter of 16mm. 2 Minimum cross-sectional area ( Figure 11 (Base opening type C).

[0210] Compared to all 14 openings, the proportion of non-standard aperture end openings is 14% (2 / 14), and the proportion of apertures with both ends opening is 80% compared to standard apertures.

[0211] In addition, compared to all 14 openings, the proportion of non-standard diameter central openings is 14% (2 / 14), and the proportion of the diameter of the central openings to the standard diameter is 90%. All openings are in line.

[0212] Here, the flow rate ratio at both ends of the nozzle is 87%, and the flow rate ratio in the center is 101%.

[0213] According to Example 6, the strands at both ends are not loose, and the strands can be continuously pulled out, thus achieving stable granulation.

[0214] [Example 7] In Example 5, the apertures of openings No. 1 and 14 at the ends of the base, and the apertures of openings No. 7 and 8 in the central opening, were changed. Otherwise, the process was the same as in Example 5, and granules were obtained. Here, the openings at both ends (No. 1 and 14) have a diameter of 16 mm. 2 The cross-sectional area, the opening in the central part (No. 7, 8) has 18mm. 2 cross-sectional area ( Figure 11 (Base opening type D).

[0215] Compared to all 14 openings, the proportion of non-standard aperture end openings is 14% (2 / 14), and the proportion of apertures with both ends opening is 90% compared to standard apertures.

[0216] In addition, compared to all 14 openings, the proportion of non-standard diameter central openings is 14% (2 / 14), and the proportion of the diameter of the central openings to the standard diameter is 95%. All openings are in line.

[0217] Here, at the nozzle outlet, the flow rate at both ends is 99%, and the flow rate in the center is 106%.

[0218] According to Example 7, the strands at both ends are not loose, and the strands can be continuously pulled out, thus achieving stable granulation.

[0219] [Comparative Example 2] In Example 5, the aperture of all openings is changed to be the same as the aperture of the calculation object that becomes the standard aperture. Figure 11 (Base opening type A), set the screw speed to 280 rpm.

[0220] In Comparative Example 2, also as Figure 14 As shown, the material at both ends flexes, resulting in a problem that cannot ensure continuous production.

[0221] Attached text description 1: Twin-screw extruder; 2: Die head; 3: Barrel; 4: Screw; 5: First mixing section; 6: Second mixing section; 7: Resin supply section; 8: Fiber supply section; 9, 9A, 9B: Nozzle; 9a, 9aB: Conical section; 9b, 9bA: Parallel section; 10: Nozzle inlet; 11: Nozzle outlet; 12: Die head support; 13: Base; 14, 14A, 14B: Nozzle die head; 15: Space inside the support; 16: Opening; 16A: Opening inlet; 16B: Opening outlet; 20: Resin flow path inlet.

Claims

1. A method for manufacturing resin granules containing reinforcing fibers, characterized in that, The extruder uses a twin-screw extruder and a die head disposed at the outlet of the twin-screw extruder. The twin-screw extruder has a first mixing section and a second mixing section disposed at a position closer to the outlet side than the first mixing section. The second mixing section has a notched reverse conveying screw element and / or includes a reverse conveying kneading disc. The mold head includes a nozzle mold head with a nozzle and a base. The base has an opening including an inlet and an outlet connected to the nozzle. The manufacturing method includes: The process of supplying resin into the twin-screw extruder from a position closer to the inlet side than the first mixing section, and performing melt mixing of the resin in the first mixing section; The reinforcing fibers are fed into the twin-screw extruder from a position closer to the outlet than the first mixing section and closer to the inlet than the second mixing section, and the resin is further melt-mixed in the presence of the reinforcing fibers; and The process of extruding the melt-blended resin containing reinforcing fibers from the nozzle outlet of the nozzle die in the form of a strand of resin containing reinforcing fibers. The nozzle and the base satisfy (1) to (8). The nozzle die head has a width of 94mm or more, and the number of nozzles arranged inside the die head is 5 to 70. On the base, the openings are arranged in a row in the horizontal direction. The resin is a propylene-based polymer with a melt flow rate of 20–500 g / 10 min at 230°C and a load of 2.16 kg. The reinforcing fiber has a fiber length of 2.5 mm to 8 mm. The reinforcing fiber has a diameter of 5 μm or more and less than 17 μm. The resin granules containing reinforcing fibers contain 5% to 50% by mass of the reinforcing fibers and 50% to 95% by mass of the resin, wherein the total of the reinforcing fibers and the resin is 100% by mass. (1) The nozzle flow path length is more than 60 mm and less than 150 mm; (2) The cross-sectional area (S1) of the minimum cross-sectional area portion of the opening of the base is 6 mm. 2 Above 80mm 2 the following; (3) The cross-sectional area (S0) of the nozzle outlet is 3 mm. 2 Above 20mm 2 the following; (4) The relationship S1≥S0 holds; (5) In the openings formed by the base, the proportion of the number of non-standard aperture openings at both ends is less than 20% of the total number; (6) In the opening formed by the base, the ratio of the diameter of the openings at both ends to the standard diameter is between 50% and 98%; (7) In the openings formed by the base, the proportion of the number of non-standard diameter central openings is less than 20% of the total number; (8) In the opening formed by the base, the ratio of the diameter of the central opening to the standard diameter is between 70% and 100%.

2. The method for manufacturing resin granules containing reinforcing fibers as described in claim 1, characterized in that, The nozzle outlets of the nozzle die head are arranged in a row in the horizontal direction, or the nozzle outlets are arranged in two rows vertically and staggered.

3. The method for manufacturing resin granules containing reinforcing fibers as described in claim 1, characterized in that, Using the base that satisfies (9), (9) In the opening formed by the base, when there are multiple non-standard aperture openings, the cross-sectional area of ​​the outermost (end) opening is less than or equal to the cross-sectional area of ​​the non-standard aperture opening that is not located at the outermost (end) opening and is less than or equal to the cross-sectional area of ​​the standard aperture opening.

4. The method for manufacturing resin granules containing reinforcing fibers as described in claim 1, characterized in that, The propylene-based polymer is an isotactic propylene homopolymer.

5. The method for manufacturing resin granules containing reinforcing fibers as described in claim 1, characterized in that, The reinforcing fiber is glass fiber or carbon fiber.

6. The method for manufacturing resin granules containing reinforcing fibers as described in claim 1, characterized in that, The screw speed of the twin-screw extruder is above 250 rpm and below 800 rpm.

7. The method for manufacturing resin granules containing reinforcing fibers as described in claim 1, characterized in that, The set temperature from the first mixing section of the twin-screw extruder to the nozzle is above 240°C and below 290°C.

8. The method for manufacturing resin granules containing reinforcing fibers as described in claim 1, characterized in that, The notched reverse conveying screw element is a single-start thread, with L / D (screw length / screw diameter) = 1 and a lead of 0.25D to 0.5D.

9. An apparatus for manufacturing resin granules containing reinforcing fibers, characterized in that, have: A twin-screw extruder having a first mixing section and a second mixing section disposed closer to the outlet side than the first mixing section, the second mixing section having a notched reverse conveying screw element and / or including a reverse conveying kneading disc; and The die head located at the outlet of the twin-screw extruder. The mold head includes a nozzle mold head with a nozzle and a base. The base has an opening including an inlet and an outlet connected to the nozzle, and the nozzle and the base satisfy (1) to (8). The nozzle die head has a width of 94mm or more, and the number of nozzles arranged inside the nozzle die head is 5 to 70. On the base, the openings are arranged in a row in the horizontal direction. (1) The nozzle flow path length is more than 60 mm and less than 150 mm; (2) The cross-sectional area (S1) of the minimum cross-sectional area portion of the opening of the base is 6 mm. 2 Above 80mm 2 the following; (3) The cross-sectional area (S0) of the nozzle outlet is 3 mm. 2 Above 20mm 2 the following; (4) The relationship S1≥S0 holds; (5) In the openings formed by the base, the proportion of the number of non-standard aperture openings at both ends is less than 20% of the total number; (6) In the opening formed by the base, the ratio of the diameter of the openings at both ends to the standard diameter is between 50% and 98%; (7) In the openings formed by the base, the proportion of the number of non-standard diameter central openings is less than 20% of the total number; (8) In the opening formed by the base, the ratio of the diameter of the central opening to the standard diameter is between 70% and 100%.

10. The apparatus for manufacturing resin granules containing reinforcing fibers as described in claim 9, characterized in that, The nozzle outlets of the nozzle die head are arranged in a row in the horizontal direction, or the nozzle outlets are arranged in two rows vertically and staggered.

11. The apparatus for manufacturing resin granules containing reinforcing fibers as described in claim 9, characterized in that, Having the base that satisfies (9), (9) In the opening formed by the base, when there are multiple non-standard aperture openings, the cross-sectional area of ​​the outermost (end) opening is less than or equal to the cross-sectional area of ​​the non-standard aperture opening that is not located at the outermost (end) opening and is less than or equal to the cross-sectional area of ​​the standard aperture opening.

12. The apparatus for manufacturing resin granules containing reinforcing fibers as described in claim 9, characterized in that, The notched reverse conveying screw element is a single-start thread with L / D = 1 and a lead of 0.25D to 0.5D.

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