Liquid blow molding equipment

Abstract

DEPCT65 Liquid blow molding equipment (1) including: nozzles (5a) which are designed to guide the flow. Flow(8) for fluids including open and closed channels(8a) and drain channels(8b); seals. (11) which is designed to open and close the opening and closing channel (8a) and includes guide holes (11a); and rods. (16) which is constructed to move in the axial direction while being guided by guide holes (11a), The leak-proof device (11) includes a pipe-shaped extension (11d) which is constructed to extend into the drain channel. (8b)When the seal (11) closes the opening and closing channel (8a), and the top surface of the extension (11d) is created. The design incorporates a fluid-repelling effect. -----------------------------------------------------------

Description

Liquid blow molding device

[0001] The present invention relates to a liquid blow molding device.

[0002] Resin containers such as those made of polypropylene (PP) or polyethylene terephthalate (PET) (PET bottles) are used to contain various content liquids such as beverages, cosmetics, pharmaceuticals, detergents, and toiletries such as shampoo. Such containers are generally formed by heating a resin preform formed into a bottomed cylindrical shape by injection molding or the like to a temperature at which the stretching effect can be exhibited, and in this state, supplying a pressurized fluid using a blow molding device and blow molding to form a predetermined shape.

[0003] A liquid blow molding device is known in which a pressurized liquid is used instead of pressurized air as the pressurized fluid supplied into the preform. In this case, by using the content liquid that is finally filled into the container as the pressurized liquid, the filling process of the content liquid into the container can be omitted, and the production process and the configuration of the liquid blow molding device can be simplified.

[0004] For example, Patent Document 1 discloses a liquid blow molding device having a nozzle that forms a liquid flow path having an opening / closing port, a seal body that opens and closes the opening / closing port and has a guide hole, and a rod that is guided by the guide hole and moves in the axial direction. The tip of the nozzle is engaged with the mouth portion of the preform disposed in the mold, the seal body is actuated to open the opening / closing port, and a pressurized liquid is supplied to the flow path, so that the pressurized liquid is supplied from the nozzle into the preform to stretch the preform and form the preform into a container having a shape along the cavity of the mold.

[0005] Japanese Patent Application Laid-Open No. 2013-208834

[0006] In conventional liquid blow molding apparatuses, such as the one shown in Patent Document 1, when the nozzle is raised after blow molding and detached from the mouth of the container, liquid adhering to the surface of the nozzle or rod may drip downwards. In particular, when a relatively viscous liquid such as shampoo or liquid detergent is used as the liquid for blow molding, the time until the liquid drips from the nozzle etc. after blow molding is long, and the liquid continues to drip for a while in a stringy manner, making it easy for the liquid to drip onto the molded container or the mold after the container has been removed, and there is a risk that the liquid will adhere to these surfaces.

[0007] This invention was made to solve these problems, and its objective is to provide a liquid blow molding apparatus that can suppress the dripping of liquid from the nozzle after blow molding.

[0008] The liquid blow molding apparatus of the present invention comprises a nozzle that forms a liquid flow path having an opening / closing port and a discharge port, a sealing body that opens and closes the opening / closing port and has a guide hole, and a rod that moves axially guided by the guide hole, wherein the sealing body has a cylindrical extension that extends into the discharge port when the opening / closing port is closed, and the tip surface of the extension is liquid-repellent.

[0009] In the liquid blow molding apparatus of the present invention, it is preferable that the tip surface and outer surface of the rod have liquid-repellent properties.

[0010] In the liquid blow molding apparatus of the present invention, it is preferable that at least one of the outer peripheral surface of the extension portion of the seal body and the inner surface forming the discharge port of the nozzle has liquid-repellent properties.

[0011] In the liquid blow molding apparatus of the present invention, it is preferable that the above configuration includes a liquid suction section for sucking up the liquid, the extension of the seal body has a suction hole connected to the tip surface of the extension, and the nozzle has a suction path connecting the suction hole and the liquid suction section when the seal body closes the opening.

[0012] According to the present invention, it is possible to provide a liquid blow molding apparatus that can suppress the dripping of liquid from the nozzle after blow molding.

[0013] This is a longitudinal cross-sectional view showing a liquid blow molding apparatus according to one embodiment of the present invention in a standby state. This is a longitudinal cross-sectional view showing the liquid blow molding apparatus shown in Figure 1 in the state during blow molding. This is a longitudinal cross-sectional view showing the liquid blow molding apparatus shown in Figure 1 with the nozzle unit detached from the container after blow molding. This is a longitudinal cross-sectional view showing the seal body tip member in the liquid blow molding apparatus shown in Figure 1. This is a bottom view of the seal body tip member shown in Figure 4.

[0014] Hereinafter, an embodiment of the present invention will be described in more detail with reference to the drawings.

[0015] As shown in Figure 1, the liquid blow molding apparatus 1 of this embodiment is a device for blow molding a bottomed cylindrical preform 2 having a mouth 2a into a container C (see Figure 2). The liquid blow molding apparatus 1 has a mold 3 in which the preform 2 can be placed. Although only a part is shown in the figure, the cavity 4 of this mold 3 is bottle-shaped and opens at the top surface of the mold 3. The preform 2 is placed in the mold 3 in an upright position with its mouth 2a facing upward. When the preform 2 is placed in the mold 3, the mouth 2a protrudes upward from the cavity 4. Although not shown in detail, the mold 3 can be opened to the left and right, and the molded container C can be removed from the mold 3 by opening the mold 3.

[0016] In this embodiment, the vertical direction refers to the vertical direction. In this embodiment, the cavity 4 of the mold 3, the nozzle tip member 7, the seal body 11, and the rod 16 all have a common central axis O that extends along the vertical direction. In this embodiment, the longitudinal section refers to a section that includes the central axis O, and the transverse section refers to a section perpendicular to the central axis O. The central axis O does not necessarily have to extend along the vertical direction; for example, it may extend in the vertical direction while being inclined with respect to the vertical direction.

[0017] As preform 2, for example, a thermoplastic resin material that exhibits stretchability upon heating, such as polypropylene (PP), polyethylene terephthalate (PET), or polyethylene (PE), can be used, which has been formed into a bottomed cylindrical shape by injection molding, compression molding, extrusion molding, etc.

[0018] A nozzle unit 5 is provided above the mold 3 so as to be movable relative to the mold 3 in the vertical direction. The nozzle unit 5 has a nozzle body 6. The nozzle body 6 is made up of multiple components, but details of these components are omitted from the illustration and explanation.

[0019] The nozzle unit 5 is provided with a cylindrical nozzle tip member 7 that can engage with the opening 2a of the preform 2. The nozzle tip member 7 has a cylindrical nozzle tip 7a whose outer diameter is smaller than the inner diameter of the opening 2a of the preform 2, and the lower end surface of the nozzle tip 7a abuts against a stepped portion formed on the inner surface of the opening 2a of the preform 2. Alternatively, the outer diameter of the nozzle tip 7a may be the same as the inner diameter of the opening 2a of the preform 2, so that the outer circumferential surface of the nozzle tip 7a abuts against the inner circumferential surface of the opening 2a. The nozzle tip member 7 can engage with the opening 2a of the preform 2 by inserting its nozzle tip 7a into the opening 2a. The nozzle tip member 7 is also clamped and fixed to the inner surface of the nozzle body 6 by a clamping portion 7b provided on its outer circumferential surface. The nozzle tip member 7 can be made of, for example, steel or resin material.

[0020] The nozzle tip member 7 is positioned coaxially with the cavity 4 of the mold 3. Therefore, when the nozzle unit 5 descends to a predetermined position, the nozzle tip 7a can be inserted into the opening 2a of the preform 2 placed in the mold 3.

[0021] A liquid flow path 8 extending along the central axis O is formed inside the nozzle body 6 and the nozzle tip member 7. The flow path 8 has an opening 8a that is opened and closed by a seal body 11, and a discharge port 8b connected to the lower end of the opening 8a. The opening 8a is formed by the inverted conical upper surface of the nozzle tip member 7, and the discharge port 8b is formed by the cylindrical inner circumferential surface of the nozzle tip member 7. A pressurized liquid supply unit 10 is connected to the portion of the flow path 8 upstream of the opening 8a via a pipe 9. The pressurized liquid supply unit 10 can supply liquid pressurized to a predetermined pressure into the interior of the preform 2 through the pipe 9, the opening 8a, and the discharge port 8b during blow molding.

[0022] For the pressurized liquid supply unit 10, it is preferable to use a configuration that uses a plunger pump as the pressurizing source, but other configurations can also be used as long as they can supply liquid pressurized to a predetermined pressure into the flow path 8.

[0023] The pressurized liquid supply unit 10 can supply relatively viscous liquids such as shampoo or liquid detergent to the flow path 8, i.e., the preform 2. This embodiment is suitable for cases where a high-viscosity liquid with a viscosity of 10,000 mPa·s or more when supplied to the preform 2, or a medium-viscosity liquid with a viscosity of 1,000 mPa·s or more but less than 10,000 mPa·s when supplied to the preform 2, is used, but it is also applicable when a low-viscosity liquid with a viscosity of less than 1,000 mPa·s is used when supplied to the preform 2.

[0024] Inside the flow path 8, a cylindrical seal body 11 is arranged that opens and closes an opening 8a and extends along the central axis O, which has a guide hole 11a. The seal body 11 is vertically movable between a closed position, where it contacts the nozzle tip member 7 from above to close the opening 8a, and an open position, where it moves away from the nozzle tip member 7 to open the opening 8a. The seal body 11 also integrally comprises a cylindrical shaft 11b, a cylindrical large-diameter portion 11c connected to the lower end of the shaft 11b and having an outer diameter larger than that of the shaft 11b, and a cylindrical extension portion 11d connected to the lower end of the large-diameter portion 11c and having an outer diameter smaller than that of the large-diameter portion 11c. The extension portion 11d is configured to extend into the discharge port 8b when the seal body 11 closes the opening 8a. When the seal body 11 moves to the closed position, which is the lower stroke end, the inverted conical contact surface 12 provided on the lower surface of the large diameter portion 11c contacts the inverted conical opening / closing surface 13 provided on the upper surface of the nozzle tip member 7 from above, thereby closing the flow path 8 at the opening / closing port 8a, i.e., closing the opening / closing port 8a. Also, when the seal body 11 moves upward from the closed position to the open position, the contact surface 12 moves upward away from the opening / closing port forming surface 13, thereby opening the flow path 8 at the opening / closing port 8a, i.e., opening the opening / closing port 8a. The shapes of the contact surface 12 and the opening / closing port forming surface 13 (opening / closing port 8a) can be changed as appropriate. Alternatively, the opening / closing port 8a may be formed by the inner circumferential surface of the nozzle tip member 7, and the opening / closing port 8a may be opened and closed by the contact and separation of the outer circumferential surface of the extension portion 11d and the inner circumferential surface of the nozzle tip member 7.

[0025] A portion of the large-diameter portion 11c and the extension portion 11d are formed by the seal body tip member 14. The seal body tip member 14 can be made of, for example, steel or resin material. The remaining portion of the large-diameter portion 11c and the shaft 11b are formed by the seal body base portion 15, which consists of multiple members. Details of the seal body base portion 15 are omitted from the illustration and description. The seal body tip member 14 has a threaded portion 14a that is screwed onto the seal body base portion 15. The seal body base portion 15 may be made of a single member. The seal body 11 may also be made of a single member.

[0026] The nozzle tip 7a is inserted into the opening 2a of the preform 2 placed in the mold 3, and the seal body 11 opens the opening 8a while the pressurized liquid supply unit 10 is activated. This allows pressurized liquid to be supplied from the pressurized liquid supply unit 10 to the inside of the preform 2 through the discharge port 8b, enabling blow molding of the preform 2. Furthermore, the supply of liquid to the molded container C can be stopped by closing the opening 8a with the seal body 11 after blow molding.

[0027] A rod 16 is provided inside the guide hole 11a of the seal body 11, which is guided by the guide hole 11a and moves in the axial direction. In other words, the rod 16 is configured to slide along the central axis O relative to the seal body 11 inside the guide hole 11a. During blow molding, by moving the rod 16 downward relative to the seal body 11, the preform 2 placed in the mold 3 can be stretched axially (vertically) by the rod 16 inside the cavity 4. In other words, the liquid blow molding apparatus 1 can use the rod 16 as a stretching rod to perform biaxial stretch blow molding of the preform 2. The rod 16 is a solid cylindrical shape.

[0028] The cylindrical inner circumferential surface of the nozzle tip member 7 is designated as the discharge port forming surface 17 that forms the discharge port 8b. The discharge port forming surface 17 is provided with an annular circumferential groove 17a that extends circumferentially in the portion above the nozzle tip 7a. The extension portion 11d of the seal body 11 is configured such that when the seal body 11 is in the closed position, the outer circumferential surface of the extension portion 11d faces the discharge port forming surface 17. Furthermore, the extension portion 11d is configured such that when the seal body 11 is in the closed position, the lower end surface of the extension portion 11d is flush with the lower end surface of the nozzle tip 7a. The extension portion 11d has an outer circumferential surface that faces the inner circumferential surface of the nozzle tip member 7 with a small gap to reduce sliding resistance against the inner circumferential surface of the nozzle tip member 7, and this outer circumferential surface is provided with an annular circumferential groove 18 that extends circumferentially. This circumferential groove 18 is configured to face the circumferential groove 17a when the seal body 11 is in the closed position.

[0029] The seal tip member 14 has an inner surface that can slide against the outer surface of the rod 16. A small gap may be provided between the inner surface of the seal tip member 14 and the outer surface of the rod 16 to reduce sliding resistance between them.

[0030] The liquid blow molding apparatus 1 has a liquid suction mechanism. This suction mechanism has a plurality of suction holes 19 provided in the extension 11d, a suction passage 20 provided in the nozzle tip member 7, and a liquid suction section 22 connected to the suction passage 20 via an on / off valve 21.

[0031] As shown in Figure 5, 20 suction holes 19 are provided at equal intervals in the circumferential direction. However, the number can be changed as appropriate, and a configuration with only one suction hole 19 is also possible. Furthermore, the multiple suction holes 19 do not have to be provided at equal intervals in the circumferential direction. As shown in Figure 4, each suction hole 19 extends from one end 19a that opens on the lower end surface of the extension 11d to the other end 19b that opens on the outer circumferential surface of the extension 11d. Also, each suction hole 19 extends linearly in the vertical direction. However, each suction hole 19 may, for example, extend linearly inclined with respect to the vertical direction. The cross-sectional shape of each suction hole 19 is circular, but is not limited to this and can be changed as appropriate. The other end 19b of each suction hole 19 opens into an annular circumferential groove 18 provided on the outer circumferential surface of the extension 11d.

[0032] As shown in Figure 1, the suction passage 20 of the nozzle tip member 7 has a circumferential groove 17a and a transverse hole 23 extending radially outward from the circumferential groove 17a, and is configured to communicate with the other ends 19b of the plurality of suction holes 19 when the seal body 11 is in the closed position. The liquid suction section 22 is connected to the transverse hole 23 via an on-off valve 21. In this way, the suction passage 20 is configured to connect the plurality of suction holes 19 and the liquid suction section 22 via the circumferential groove 18 when the seal body 11 closes the on-off opening 8a. The on-off valve 21 is preferably provided inside the nozzle unit 5, but may also be provided outside the nozzle unit 5. The on-off valve 21 is configured as an electrically operated control valve and can be opened and closed by a control means (not shown). However, the on-off valve 21 may be configured as, for example, a pneumatic or hydraulic control valve.

[0033] The liquid suction unit 22 is configured, for example, by a vacuum pump, and can suck liquid from the suction passage 20 when the on / off valve 21 is opened. Therefore, when the seal body 11 is in the closed position and the lower end surface of the rod 16 is approximately flush with the nozzle tip 7a and extension 11d, the liquid suction unit 22 can suck up liquid adhering to these lower end surfaces through the multiple suction holes 19 and suction passage 20, thereby preventing the liquid from dripping.

[0034] In this embodiment, a nozzle 5a is formed by a nozzle body 6 and a nozzle tip member 7, which together form a flow path 8 having an opening / closing port 8a and a discharge port 8b. In this embodiment, a nozzle core 5b is formed by a seal body 11 and a rod 16, which together form the opening / closing port 8a. The nozzle 5a and the nozzle core 5b together constitute a nozzle unit 5.

[0035] When the seal body 11 is in the closed position, liquid may adhere to the liquid passage downstream of the opening 8a in the nozzle unit 5. If liquid adheres and accumulates after blow molding, it may drip down and adhere to the molded container C or the mold 3 after the container C has been removed. Therefore, in this embodiment, in order to quickly remove any liquid that adheres after blow molding and to prevent liquid from accumulating, the parts where liquid tends to adhere and accumulate are given a liquid-repellent configuration.

[0036] In this embodiment, in order to suppress the dripping of liquid from the nozzle 5a after blow molding, the lower end surface of the extension portion 11d of the seal body 11, the lower end surface and outer peripheral surface of the rod 16 (the portion that protrudes downward from the lower end surface of the extension portion 11d), and at least one of the outer peripheral surface of the extension portion 11d and the discharge port forming surface 17 are configured to be liquid-repellent.

[0037] By having a liquid-repellent lower end surface on the extension 11d of the seal body 11, liquid can be quickly drained from the lower end surface of the extension 11d, which is the part where liquid is most likely to accumulate, due to contact with the liquid, movement of liquid from the rod 16 as it rises while being handled by the guide hole 11a, and movement of liquid from the discharge port forming surface 17 as the seal body 11 descends, thereby efficiently suppressing liquid dripping. Furthermore, by having a liquid-repellent lower end surface and outer circumferential surface on the rod 16, the amount of liquid adhering to the outer surface of the rod 16 after blow molding can be reduced. In addition, by having a liquid-repellent lower end surface on the outer circumferential surface of the extension 11d and the discharge port forming surface 17 (for example, the portion below the circumferential grooves 17a and 18), the amount of liquid seeping out and dripping from the gap between the outer circumferential surface of the extension 11d and the discharge port forming surface 17 after blow molding can be reduced.

[0038] In this application, "having liquid-repellent properties" means having liquid-repellent (water-repellent) properties such that the contact angle with pure water is 110° or more, and the rolling angle of pure water (10 μL) is 30° or less. Here, the contact angle refers to the contact angle when pure water is dropped onto a plate made of the same material as the liquid-repellent portion, and can be measured using a contact angle measuring device (for example, a contact angle meter: CA-D, manufactured by Kyowa Interface Science Co., Ltd.). The rolling angle refers to the angle at which the water droplet begins to slide off when pure water is dropped onto a plate made of the same material as the liquid-repellent portion, and the plate is tilted.

[0039] Liquid repellency can be imparted by known and appropriate means. Liquid repellency may be obtained by the material or structure of the substrate surface itself, or by the material or structure of the coating layer covering the substrate surface. Suitable materials include silica-based materials, fluorine-based materials, silicone-based materials, etc. Suitable structures include micro-textured structures, fractal structures, reentrant structures, etc. The means for providing the coating layer are not particularly limited; for example, vapor deposition, coating, etc., can be used.

[0040] Next, an example of the procedure for blow-molding the preform 2 using such a liquid blow molding apparatus 1 is shown.

[0041] First, as shown in Figure 1, the preform 2 is placed in the mold 3 with the seal body 11 in the closed position and the opening 8a closed. Next, the nozzle unit 5 descends and the nozzle tip 7a is inserted into the opening 2a of the preform 2. At this time, the rod 16 is at its origin position, with its lower end surface flush with the lower end surface of the extension 11d of the seal body 11.

[0042] Next, the seal body 11 moves to the open position, opening the opening 8a. When the opening 8a is opened, pressurized liquid is supplied from the pressurized liquid supply unit 10 to the inside of the preform 2 via the flow path 8, and the preform 2 is blow-molded (liquid blow-molded) by the liquid. Also, during blow molding, the rod 16 descends, and the preform 2 is stretched axially (vertically) by the rod 16. Through this biaxial stretch blow molding, the preform 2 is molded into a bottle-shaped container C that follows the cavity 4 of the mold 3, as shown in Figure 2.

[0043] Once blow molding is complete, the seal body 11 descends to the closed position, the opening 8a closes, and the liquid supply stops. The rod 16 then rises to a position where its lower end surface is flush with the lower end surface of the extension 11d of the seal body 11, i.e., the origin position. As shown in Figure 3, the nozzle unit 5 rises and the nozzle tip 7a detaches upward from the mouth Ca of the container C. At this time, as the rod 16 rises and is withdrawn from the liquid inside the container C, a headspace equal to the volume of the withdrawn stretched rod is formed inside the container C. However, the headspace may be formed by other methods. Note that the rod 16 may be used not as a rod for biaxial stretching, but as a rod for forming the headspace.

[0044] Further, when the nozzle unit 5 rises and the nozzle tip 7a disengages upward from the mouth Ca of the container C, at least one of the lower end surface of the extension portion 11d of the seal body 11, the lower end surface and the outer peripheral surface of the rod 16, and the outer peripheral surface of the extension portion 11d and the discharge port forming surface 17 has liquid repellency, thereby suppressing the dripping of the liquid from the nozzle 5a. In particular, according to this liquid blow molding apparatus 1, even when a liquid having a relatively high viscosity such as shampoo or liquid detergent is used as the liquid, the dripping of the liquid can be suppressed, and an increase in cycle time can be suppressed, and blow molding can be efficiently performed.

[0045] Further, after the completion of blow molding, the on-off valve 21 is opened, the liquid suction portion 22 starts operating, and the liquid adhering to the lower end surfaces of the nozzle tip 7a, the extension portion 11d, and the rod 16 is sucked from the plurality of suction holes 19 and the suction passage 20 as shown by the broken line arrows in FIG. 3. At this time, when the rising rod 16 is guided by the guide hole 11a of the seal body 11, even if the liquid adhering to the outer peripheral surface of the rod 16 moves to the lower end surface of the rod 16, the liquid can be efficiently sucked from one end 19a of the plurality of suction holes 19 provided on the lower end surface of the extension portion 11d disposed adjacent to the lower end surface of the rod 16, and the dripping of the liquid can be more reliably suppressed.

[0046] It is needless to say that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist thereof.

[0047] For example, in the above-described embodiment, the nozzle tip 7a and the extension portion 11d have a cylindrical shape, but are not limited thereto, and may have a cylindrical shape having a cross-sectional shape such as a polygon or an ellipse, for example. However, when the mouth portion 2a of the preform 2 has a cylindrical shape, the outer peripheral surface of the nozzle tip 7a preferably has a cylindrical shape.

[0048] Further, in the above-described embodiment, the rod 16 has a solid cylindrical shape, but is not limited thereto, and may have, for example, a flow path connected to the pressurized liquid supply portion 10 inside thereof. In this case, the rod 16 may be composed of, for example, a cylindrical outer cylinder and a poppet valve-shaped opening and closing rod that can open and close the lower end surface of the outer cylinder.

[0049] Furthermore, in the above embodiment, the extension portion 11d is configured such that its lower end surface is flush with the lower end surface of the nozzle tip 7a when the seal body 11 is in the closed position. However, the configuration is not limited to this, and the lower end surface of the extension portion 11d may be positioned above or below the lower end surface of the nozzle tip 7a when the seal body 11 is in the closed position. Furthermore, in the above embodiment, the lower end surface of the extension portion 11d extends horizontally. However, the configuration is not limited to this, and for example, it may be inclined upward or downward radially inward.

[0050] Furthermore, in the above embodiment, the lower end surface of the extension portion 11d of the seal body 11, the lower end surface and outer circumferential surface of the rod 16, and at least one of the outer circumferential surface of the extension portion 11d and the discharge port forming surface 17 are liquid-repellent. However, the embodiment is not limited to this, and for example, only the lower end surface of the extension portion 11d may be liquid-repellent.

[0051] Furthermore, the configuration may be one in which the liquid suction section 22, suction hole 19, circumferential groove 18, suction passage 20, and on / off valve 21 are not provided.

[0052] 1 Liquid blow molding apparatus 2 Preform 2a Mouth section 3 Mold 4 Cavity 5 Nozzle unit 5a Nozzle 5b Nozzle core 6 Nozzle body 7 Nozzle tip member 7a Nozzle tip 7b Clamping section 8 Flow path 8a Opening / closing port 8b Discharge port 9 Piping 10 Pressurized liquid supply section 11 Seal body 11a Guide hole 11b Shaft body 11c Large diameter section 11d Extension section 12 Contact surface 13 Opening / closing port forming surface 14 Seal body tip member 14a Threaded section 15 Seal body base section 16 Rod 17 Discharge port forming surface 17a Circumferential groove 18 Circumferential groove 19 Suction hole 19a One end 19b Other end 20 Suction passage 21 Opening / closing valve 22 Liquid suction section 23 Side hole O Central axis C Container Ca Mouth

Claims

DEPCT651. Liquid blow molding device comprising: a nozzle designed to direct the flow path for the liquid, including open and closed channels and a vent channel; a seal designed to open and close the open and closed channels and including a guide hole; and a rod designed to move in the axial direction while guided by the guide hole, where the seal includes a tubular extension designed to extend into the vent channel when the seal closes the open and closed channels, and the top surface of the extension is designed to have a liquid-repelling condition.

2. Liquid blow molding device according to claim 1, where the top surface and the outer boundary surface of the rod are designed to have a liquid-repelling condition.

3. Liquid blow molding device according to claim 1 or 2, where at least one of the outer boundary surfaces of the seal extension and the inner surface defining the nozzle vent channel are designed to have a liquid-repelling condition.4.A liquid blow molding device as described in any of the claims 1 through 3, which is further incorporated with a liquid suction unit designed to draw in the liquid, where the seal extension includes a suction port designed to connect to the top surface of the extension, and a nozzle includes a suction path designed to connect the suction port and the liquid suction unit when the seal closes the opening and closing.