EVA-based composite sole structure and preparation device

Abstract

The invention relates to the field of EVA shoe soles, and particularly discloses an EVA-based composite shoe sole structure and a preparation device.The EVA-based composite shoe sole structure comprises an EVA midsole and an EVA outsole which are subjected to secondary foaming bonding, the two faces of the midsole are each provided with a sinking part, the outsole is provided with an empty groove corresponding to the sinking parts, the two sides of the empty groove are provided with reinforcing ribs, and the reinforcing ribs are arranged on the two sides of the empty groove; the reinforcing ribs correspond to the sinking parts; wherein the EVA insole is prepared from the following components in parts by weight: 53 to 66 parts of ethylene-vinyl acetate copolymer, 22 to 27 parts of styrene-isoprene-styrene block copolymer, 13 to 16 parts of ethylene-acrylic acid copolymer and 1 to 6 parts of azodicarbonamide. The sinking part is arranged on the insole, the thickness of the sinking part is small, the good bending performance is provided, the outsole is synchronously bent to form the reinforcing ribs, the weak supporting capacity of the insole is compensated through the thin-wall outsole with high supporting strength, the overall weight of the sole structure is reduced, the sinking part is arranged in a double-face mode, the abrupt fluctuation of the sole structure is reduced, and the service life of the sole structure is prolonged. And the method is more suitable for flat feet.

Description

TECHNICAL FIELD

[0001] The application relates to an EVA sole technology, in particular to an EVA-based composite sole structure and a preparation device. BACKGROUND

[0002] It is known that an EVA-based composite sole is a high-performance sole formed by combining a multilayer structure EVA base with a rubber sole, which is suitable for sports shoes such as running shoes, basketball shoes and badminton shoes. The midsole of the sports shoes is usually made of twice-foamed EVA and cooperated with rubber to form a wear-resistant outsole.

[0003] For example, an application with the application publication number CN104856344B, the application publication date of November 6, 2018, and the name of 'twice-molded sandwich EVA foaming wear-resistant sports shoe sole and manufacturing method thereof' relates to a sole. The twice-molded sandwich EVA foaming wear-resistant sports shoe sole is provided with an upper wear-resistant material layer and a lower wear-resistant material layer, and an ultralight material layer is arranged between the upper wear-resistant material layer and the lower wear-resistant material layer. The raw material composition of the upper and lower wear-resistant material layers is ethylene-vinyl acetate copolymer, ethylene-octene copolymer, ternary ethylene-propylene rubber, talcum powder, wear-resistant agent, stearic acid, zinc stearate, zinc oxide, dicumyl peroxide, azodicarbonamide and color masterbatch. The raw material composition of the ultralight material layer is ethylene-vinyl acetate copolymer, ethylene-octene copolymer, ethylene-acrylic acid copolymer, talcum powder, stearic acid, zinc stearate, zinc oxide, dicumyl peroxide, azodicarbonamide and color masterbatch. The twice-molded method is adopted to manufacture the sole. The wear-resistant performance and lightness are achieved.

[0004] The prior art has the following disadvantages. In the EVA-based composite sole for running shoes, a recess corresponding to the arch support area is arranged on the outsole and the midsole, which provides the freedom of the sole when bending and the freedom of the sole when deforming, thereby improving the flexibility and the buffering performance. However, excessive freedom will weaken the supporting capacity and easily cause the muscle fatigue of the foot, and the comfort is reduced after a long time of wearing. SUMMARY

[0005] The application aims to provide an EVA-based composite sole structure and a preparation device to solve the above problems in the prior art.

[0006] In order to achieve the above-mentioned purpose, the application provides the following technical scheme: an EVA-based composite sole structure and a preparation device, which comprises a twice-foamed and bonded EVA midsole and an outsole. The midsole is provided with a sunken part on both sides. The outsole is provided with a hollow groove corresponding to the sunken part. The hollow groove is provided with a reinforcing rib on both sides. The reinforcing rib corresponds to the sunken part. The EVA midsole comprises the following components: 53-66 parts of ethylene-vinyl acetate copolymer, 22-27 parts of styrene-isoprene-styrene block copolymer, 13-16 parts of ethylene-acrylic acid copolymer, 1-6 parts of azodicarbonamide, and 0.5-2 parts of dicumyl peroxide.

[0007] The EVA-based composite sole preparation device is used for preparing the EVA-based composite sole structure, and further comprises an upper die and a lower die, the two of which form a corresponding die cavity therebetween, the die cavity is used for pressing the sole structure, and a bottom pressing block is arranged on the lower die, the bottom pressing block is used for pressing out the sunken part and the reinforcing rib together with the die.

[0008] As a further description of the above technical solution: the bottom pressing block extends out of the lower die, a pressing protrusion is connected to the lower die along a diagonal line in a sliding manner, the pressing protrusion is driven to move together with the bottom pressing block, so that the bottom pressing block extrudes the sole structure before the die cavity is pressed.

[0009] As a further description of the above technical solution: a die pressing plate is arranged on the bottom pressing block, a stretching slot is formed in the die pressing plate, the die pressing plate is used for extruding the sunken part together with the bottom pressing block, and the bottom pressing block is used for stretching and extruding the reinforcing rib along the stretching slot.

[0010] As a further description of the above technical solution: a top rod is arranged on the die pressing plate, the top rod is movably arranged on the bottom pressing block, and the die pressing plate is used for staying on the sole structure together with the upper die and the lower die when the upper die and the lower die are separated.

[0011] As a further description of the above technical solution: elastic plates are symmetrically arranged on the inner wall of the die pressing plate, the elastic plates are pushed by the bottom pressing block, so that the die pressing plate moves.

[0012] As a further description of the above technical solution: a limiting rotating sleeve is rotatably connected to the top rod, and the limiting rotating sleeve is slidably connected to the bottom pressing block.

[0013] As a further description of the above technical solution: a first steam channel and a second steam channel are respectively formed in the lower die, and an air inlet hole and an air outlet hole are respectively formed in the two bottom pressing blocks, the air inlet hole and the air outlet hole are in communication with the first steam channel and the second steam channel.

[0014] As a further description of the above technical solution: a sliding communication groove is formed in the second steam channel, and the sliding communication groove is in movable communication with the air inlet hole.

[0015] As a further description of the above technical solution: a profile channel and an outer side channel are formed in the upper die, the profile channel is in communication with the second steam channel when the upper die and the lower die are closed, and the outer side channel is in communication with the first steam channel when the upper die and the lower die are closed.

[0016] In the above technical solution, the EVA-based composite shoe sole structure and the preparation device provided by the application have the following beneficial effects: the midsole is provided with a sunken part, the thickness of the sunken part is small, good bending performance is provided, and the large sole is bent synchronously to form a reinforcing rib, the support capacity of the midsole is compensated by the thin-walled large sole with high support strength, the overall weight of the shoe sole structure is reduced, the sunken part is provided on both sides, the abrupt ups and downs of the shoe sole structure are reduced, and the shoe sole structure is more suitable for flat feet. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art based on these drawings.

[0018] Figure 1 The shoe sole structure schematic diagram provided by the embodiment of the present application; Figure 2 The shoe sole structure explosion schematic diagram provided by the embodiment of the present application; Figure 3 The structure schematic diagram of the upper die and the lower die provided by the embodiment of the present application; Figure 4 The structure explosion schematic diagram of the upper die and the lower die provided by the embodiment of the present application; Figure 5 The position schematic diagram of the convex module and the bottom pressing block 41 provided by the embodiment of the present application; Figure 6 The shoe sole structure and the pressing mold plate explosion schematic diagram provided by the embodiment of the present application; Figure 7 The Figure 6 The enlarged schematic diagram of the middle A; Figure 8 The explosion schematic diagram of the shoe sole structure preparation device provided by the embodiment of the present application; Figure 9 The Figure 8 The enlarged schematic diagram of the middle B; Figure 10 The structure cross-sectional schematic diagram of the upper die and the lower die provided by the embodiment of the present application; Figure 11 The Figure 10 The enlarged schematic diagram of the middle C; Figure 12 The structure cross-sectional schematic diagram of the upper die and the lower die provided by the embodiment of the present application from another angle; Figure 13 The Figure 12 The enlarged schematic diagram of the middle D; Figure 14 The upper die perspective view provided for the embodiment of the present application; Figure 15 The lower die perspective view provided for the embodiment of the present application; Figure 16 The bottom pressing block perspective view provided for the embodiment of the present application.

[0019] Mark explanation: 1, the big bottom; 11, the reinforcing rib; 2, the EVA insole; 21, the sunken part; 30, the mold cavity; 31, the upper die; 311, the male die block; 312, the protruding part; 313, the outer side channel; 314, the profile channel; 32, the lower die; 321, the pressing die groove; 322, the bottom sliding groove; 323, the first steam channel; 324, the second steam channel; 3241, the sliding communication groove; 33, the clamping plate; 331, the clamping groove; 40, the extrusion protrusion; 401, the first elastic piece; 402, the sliding hole; 41, the bottom pressing block; 411, the air inlet hole; 412, the air outlet hole; 42, the pressing die plate; 421, the stretching groove; 422, the elastic plate; 51, the ejector rod; 511, the side fixed rod; 512, the side protruding plate; 52, the limiting rotating sleeve; 521, the limiting surface; 522, the second elastic piece. DETAILED DESCRIPTION

[0020] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below in conjunction with the drawings.

[0021] Embodiment one Please refer to Figures 1-2 The present application provides a technical solution: an EVA-based composite shoe sole structure, comprising a twice-foamed and bonded EVA insole 2 and a big bottom 1, the big bottom 1 is made of wear-resistant rubber and has good support capacity, the EVA insole 2 is provided with a sunken part 21 on each side, the big bottom 1 is provided with a corresponding air slot which is recessed towards the sunken part 21, and reinforcing ribs 11 are arranged on both sides of the air slot and correspond to the sunken part 21 to increase the support capacity of the EVA insole 2.

[0022] The EVA insole 2 comprises the following components in weight units: ethylene-vinyl acetate copolymer 53-66 parts, styrene-isoprene-styrene block copolymer 22-27 parts, ethylene-acrylic acid copolymer 13-16 parts, azodicarbonamide 1-6 parts, and dicumyl peroxide 0.5-2 parts.

[0023] The big bottom 1 can be made of natural rubber of a raw rubber system and has good elasticity, strength and wear resistance, wherein vulcanizing agents, zinc oxide, stearic acid and accelerators (CZ, DM or NS) can be added for vulcanization treatment to increase wear resistance and strength.

[0024] Embodiment two Please refer to Figures 1-16 The embodiment of the present application provides a technical scheme: an EVA-based composite shoe sole preparation device, further comprising an upper die 31 and a lower die 32, the upper die 31 is provided with a convex die block 311, the lower die 32 is provided with a pressing die groove 321, the pressing die groove 321 corresponds to the convex die block 311, and a die cavity 30 is formed between the pressing die groove 321 and the convex die block 311, the die cavity 30 is used for pressing the shoe sole structure, the lower die 32 is provided with a bottom pressing block 41, the convex die block 311 is provided with a convex part 312 corresponding to the bottom pressing block 41, before the mold enters the insole hot-pressing forming machine, the outsole 1 is placed at the bottom of the pressing die groove 321, and the hollow groove on the outsole 1 corresponds to the bottom pressing block 41, then the EVA midsole 2 is placed in the pressing die groove 321 to be attached to the outsole 1, and then the upper die 31 and the lower die 32 are combined to ensure that the die cavity 30 completely wraps the outsole 1 and the EVA midsole 2, and the mold is placed in the insole hot-pressing forming machine to perform hot-pressing secondary foaming, during the hot-pressing process, the bottom pressing block 41 and the convex part 312 press the sinking part 21 on both sides of the shoe sole structure, and press the hollow groove of the outsole 1 to the EVA midsole 2 to form the reinforcing rib 11, the adhesion of the outsole 1 and the EVA midsole 2 is completed, and the double-sided sinking part 21 is formed.

[0025] Further, the upper die 31 is symmetrically connected with a clamping plate 33, the lower die 32 is symmetrically provided with a clamping groove 331, when the upper die 31 and the lower die 32 are combined, the clamping plate 33 is clamped at the end of the clamping groove 331 to fix the upper die 31 and the lower die 32.

[0026] In another embodiment of the present application, the lower die 32 is provided with a bottom sliding groove 322 for sliding of the bottom pressing block 41, the bottom pressing block 41 extends out of the lower die 32, the lower die 32 is provided with a sliding hole 402 along the diagonal line, the sliding hole 402 is slidably connected with an extrusion protrusion 40, the extrusion protrusion 40 is provided with a first elastic member 401 (the first elastic member 401 can be a spring), and the first elastic member 401 is used to push the extrusion protrusion 40 to extend out of the lower die 32.

[0027] During the process of integral molding and pressing, the pressing speed is fast, the deformation degree is high, and the deformation cannot be gradual, so that the molding speed of the two-sided sinking part 21 in the shoe sole structure is too fast, and tearing is prone to occur.

[0028] When the mold is put into the hot press forming machine after the mold is closed, the extrusion protrusion 40 is in the state of extending out of the lower mold 32, providing the freedom of extension of the bottom pressing block 41, and then during the mold closing process, the first stage pressure and hot steam are given to the bottom pressing block 41, so that the bottom pressing block 41 moves to pre-press the insole structure, so that it first performs a small amplitude thermal plastic deformation, at this time the extrusion protrusion 40 and the bottom pressing block 41 slide along the lower mold 32 driven by the hot press forming machine, so that the bottom pressing block 41 extrudes the sole structure before the whole mold cavity 30 is pressed, and then when the bottom pressing block 41 is completed to extend into the mold cavity 30, the hot press forming machine will press the upper mold 31 and the lower mold 32 to perform overall hot pressing, and the two-stage pressing relieves the deformation speed at the sunken part 21, and reduces the tearing.

[0029] In another embodiment of the present application, the bottom pressing block 41 is provided with a pressing plate 42, which contacts the sunken part 21 of the sole structure, as shown in Figure 6 The pressing plate 42 is provided with a stretching slot 421, and the pressing plate 42 is stretched to expand the pressing plate 42 along the stretching slot 421 to extrude the outsole 1 to the EVA midsole 2, so as to facilitate the formation of the reinforcing rib 11 and increase the adhesion between the outsole 1 and the EVA midsole 2. The pressing plate 42 remains on the sole structure after the upper mold 31 and the lower mold 32 are pressed, and when the sole structure is not completely cooled, the remaining pressing plate 42 plays a shaping role, avoiding excessive deformation due to natural shrinkage of the sunken part 21 during cooling, and maintaining the shape accuracy after cooling.

[0030] Preferably, as shown in Figure 6 、 Figure 7 and Figure 11 The pressing plate 42 is provided with a top rod 51 movably arranged on the bottom pressing block 41, and before pressing, the pressing plate 42 is first fixed on the bottom pressing block 41 by the top rod 51, and then the pressing plate 42 remains on the sole structure after the upper mold 31 and the lower mold 32 are demolded, and when the sole is cooled, the pressing plate 42 can be pulled out from the already cooled sole structure by the top rod 51, which is convenient to operate.

[0031] Furthermore, a limiting sleeve 52 is rotatably connected to the ejector pin 51. A semi-circular arc-shaped side protrusion 512 is provided on the ejector pin 51. A second elastic element 522 (which can be a spring) is provided between the limiting sleeve 52 and the ejector pin 51. A limiting surface 521 is provided on the limiting sleeve 52, and an arc-shaped hole is provided on the bottom pressure block 41. The arc-shaped hole corresponds to the cross-section of the limiting sleeve 52. A limiting hole is also provided in the arc-shaped hole. The limiting hole is used to prevent the side protrusion 512 from rotating along the axis. Before the lower mold 32 is installed into the base 1, the limiting sleeve 52 is rotated to misalign the limiting sleeve 52 and the ejector pin 51, and then inserted into the arc-shaped hole. Inside the cavity, the limiting hole and the limiting side protrusion 512 restrict the limiting sleeve 52 and the ejector rod 51. After the mold is closed, the upper mold 31 is opened and the lower mold 32 is moved out of the hot press molding machine to reduce the restriction on the bottom pressure block 41. Then the lower mold 32 is lifted, and the bottom pressure block 41 falls with gravity. At this time, because the pressure plate 42 is stuck on the insole structure, the ejector rod 51 and the bottom pressure block 41 are separated. Due to the pull of the second elastic element 522, the arc-shaped hole and the cross section of the limiting sleeve 52 are misaligned. Then the lower mold 32 can be moved back to a hard object to push out the ejector rod 51, which helps the insole structure and the pressing groove 321 on the lower mold 32 to separate.

[0032] Furthermore, the top rod 51 is equipped with symmetrical side fixing rods 511. When carbon plates need to be installed on the sole structure, grooves are pre-cut at both ends of the bent carbon plate, and the side fixing rods 511 are used to fix the bent carbon plate along the grooves. Then, the bent carbon plate replaces the pressing template 42 for fixing. After the pressing is completed, the top rod 51 can be removed from the bent carbon plate to complete the fixing of the bent carbon plate.

[0033] Preferred, such as Figure 13 As shown, elastic plates 422 are symmetrically arranged on the inner wall of the pressure plate 42. The elastic plates 422 and the inner wall of the pressure plate 42 are hinged. When the mold is closed, the elastic plates 422 are pushed by the bottom pressure block 41 and gradually change from an inclined state to a horizontal state, and stretch the folded stretching groove 421, which plays the role of reinforcing the reinforcing rib 11.

[0034] In another embodiment provided by the present invention, such as Figures 10-15 As shown, the lower mold 32 is provided with a first steam channel 323 and a second steam channel 324 respectively. The two bottom pressure blocks 41 are provided with an air inlet 411 and an air outlet 412 respectively. The air inlet 411 and the air outlet 412 are connected to the first steam channel 323 and the second steam channel 324. When the mold enters the hot press molding machine, the outlet of the steam pipe is connected to one of the bottom pressure blocks 41 on the plate. At this time, the hole on the other bottom pressure block 41 can be used as the air outlet 412 to complete the circulation of hot steam.

[0035] Further, the upper die 31 is provided with a profile passage 314 and an outer passage 313. The profile passage 314 is communicated with the second steam passage 324 when the mold is closed, and the outer passage 313 is communicated with the first steam passage 323 when the mold is closed. The second steam passage 324 and the first steam passage 323 respectively heat the area of the zone and the whole, so as to ensure the temperature of the area of the sink 21 during the secondary molding.

[0036] Preferably, the second steam passage 324 is provided with a sliding communication groove 3241, which is in movable communication with the air inlet hole 411. The bottom pressing block 41 will slide along the lower die 32, as shown in the figure. After the upper die 31 and the lower die 32 are closed into the hot press forming machine, the hot steam will enter the sliding communication groove 3241 along one of the bottom pressing blocks 41 during pressing, so as to concentrate heating on the second steam passage 324. After the mold completes the pre-pressing of the sink 21, the air inlet hole 411 will be communicated with the first steam passage 323, so as to heat the whole mold. Figure 9

[0037] In use, first, according to whether the composite sole structure needs to add a carbon plate, the required ejector rod 51 is selected. Then, before the big sole 1 is loaded into the lower die 32, the limiting sleeve 52 is rotated, the limiting sleeve 52 and the ejector rod 51 are misaligned, and they are inserted into the arc-shaped hole. The limiting hole and the limiting side lug 512 limit the limiting sleeve 52 and the ejector rod 51. Then, the air slot on the big sole 1 is matched with the bottom pressing block 41. Then, the EVA midsole 2 is placed into the pressing mold groove 321 to be attached to the big sole 1. Then, the upper die 31 and the lower die 32 are closed, and the clamping plate 33 is rotated to be locked and fixed. The mold is placed into the insole hot press forming machine to be hot-pressed. During hot-pressing, the first-stage pressure and hot steam are first given to the bottom pressing block 41, so that the bottom pressing block 41 moves to pre-press the insole structure, so that it first undergoes small-amplitude thermal plastic deformation. At this time, the extrusion protrusion 40 and the bottom pressing block 41 slide along the lower die 32 under the driving of the hot press forming machine, so that the bottom pressing block 41 extrudes the sole structure before the whole is pressed in the closed mold cavity 30. Then, when the bottom pressing block 41 is completely inserted into the closed mold cavity 30, the hot press forming machine presses the upper die 31 and the lower die 32 to perform overall hot-pressing. After hot-pressing is completed, the upper die 31 is opened, the lower die 32 is moved out of the hot press forming machine, the limitation of the bottom pressing block 41 is reduced, and then the lower die 32 is suspended, so that the bottom pressing block 41 falls under gravity. At this time, because the pressing plate 42 is retained on the insole structure, the ejector rod 51 and the bottom pressing block 41 are separated, and because the second elastic member 522 is pulled, the cross section of the arc-shaped hole and the limiting sleeve 52 is misaligned. Then, the lower die 32 can be moved to a hard object again, the ejector rod 51 is ejected, and the insole structure is separated from the pressing mold groove 321 on the lower die 32.

[0038] ​The foregoing merely illustrates some exemplary embodiments of the application, and it will be appreciated that those skilled in the art will be able to devise various modifications without departing from the spirit and scope of the application. The appended drawings and description are illustrative only, and are not intended to be limiting.

Claims

1. An EVA-based composite shoe sole structure, characterized in that, The invention includes a secondary foamed and bonded EVA midsole (2) and outsole (1). The midsole (2) has a recessed portion (21) on both sides. The outsole (1) has a groove corresponding to the recessed portion (21). Reinforcing ribs (11) are provided on both sides of the groove. The reinforcing ribs (11) correspond to the recessed portion (21). The EVA midsole (2) comprises the following components (by weight): 53-66 parts of ethylene-vinyl acetate copolymer, 22-27 parts of styrene-isoprene-styrene block copolymer, 13-16 parts of ethylene-acrylic acid copolymer, 1-6 parts of azodicarbonamide, and 0.5-2 parts of dicumyl peroxide.

2. An EVA-based composite shoe sole preparation apparatus, used to prepare the EVA-based composite shoe sole structure according to claim 1, characterized in that, It also includes an upper mold (31) and a lower mold (32), which form a corresponding mold cavity (30) between them. The mold cavity (30) presses the shoe sole structure. The lower mold (32) is provided with a bottom pressing block (41). The bottom pressing block (41) presses out the recessed part (21) and the reinforcing rib (11) with the mold.

3. The EVA-based composite shoe sole preparation device according to claim 2, characterized in that, The bottom pressure block (41) extends out of the lower mold (32), and the lower mold (32) has a diagonally connected extrusion protrusion (40). The extrusion protrusion (40) and the bottom pressure block (41) are driven to move together, so that the bottom pressure block (41) extrudes the shoe sole structure before the mold cavity (30) is pressed.

4. The EVA-based composite shoe sole preparation device according to claim 2, characterized in that, The bottom pressure block (41) is provided with a pressure template (42), and the pressure template (42) is provided with a stretching groove (421). The pressure template (42) moves with the bottom pressure block (41) to squeeze the sunken part (21), and the bottom pressure block (41) stretches and extrudes the reinforcing rib (11) along the stretching groove (421).

5. The EVA-based composite shoe sole preparation apparatus according to claim 4, characterized in that, The pressing template (42) is provided with a top rod (51), which is movably disposed on the bottom pressing block (41). The pressing template (42) is separated from the upper mold (31) and the lower mold (32) and remains on the shoe sole structure.

6. The EVA-based composite shoe sole preparation apparatus according to claim 4, characterized in that, The inner wall of the pressure template (42) is symmetrically provided with elastic plates (422). The elastic plates (422) are pushed by the bottom pressure block (41) to move the pressure template (42).

7. The EVA-based composite shoe sole preparation apparatus according to claim 5, characterized in that, A limiting sleeve (52) is rotatably connected to the top rod (51), and the limiting sleeve (52) is slidably connected to the bottom pressure block (41) by drive.

8. The EVA-based composite shoe sole preparation apparatus according to claim 2, characterized in that, The lower mold (32) is provided with a first steam channel (323) and a second steam channel (324), and the two bottom pressure blocks (41) are provided with an air inlet (411) and an air outlet (412), respectively. The air inlet (411) and the air outlet (412) are connected to the first steam channel (323) and the second steam channel (324).

9. The EVA-based composite shoe sole preparation apparatus according to claim 8, characterized in that, The second steam passage (324) is provided with a sliding connecting groove (3241), which is movably connected to the air inlet (411).

10. The EVA-based composite shoe sole preparation apparatus according to claim 8, characterized in that, The upper mold (31) is provided with a surface channel (314) and an outer channel (313). The surface channel (314) is connected to the second steam channel (324) when the mold is closed, and the outer channel (313) is connected to the first steam channel (323) when the mold is closed.

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