Mold and method for molding ultraviolet curing resin

Abstract

To provide a mold in which an ultraviolet curable resin does not remain in a gate part, and a method for molding the ultraviolet curable resin using the mold.SOLUTION: The mold according to the present disclosure is a mold for molding a resin molded article by transmitting irradiated ultraviolet rays and curing an ultraviolet curing resin injected into the mold, and the mold is composed of a fluororesin having a total light transmittance of 50% or more and a water contact angle of 100 ° or more. With this configuration, it is possible to provide a mold in which the ultraviolet curable resin does not remain in the gate portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a molding die and a method for molding ultraviolet curable resin. [Background technology]

[0002] Patent Document 1 discloses a molding die that transmits irradiated ultraviolet light and cures ultraviolet curable resin injected inside to form a resin molded product. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-065339 Summary of the Invention [Problem to be solved by the invention]

[0004] However, such a mold has a gate that guides the UV-curable resin to the cavity. Because the gate has a small diameter, it is difficult to apply a mold release agent or coating to the inside. As a result, there is a risk that the UV-curable resin will remain in the gate, causing gate clogging.

[0005] The present disclosure has been made in consideration of the above-described circumstances, and provides a molding die in which no ultraviolet curable resin remains in the gate portion, and a molding method for ultraviolet curable resin using the molding die. [Means for solving the problem]

[0006] A molding die according to one embodiment of the present disclosure comprises: A molding die that transmits irradiated ultraviolet light and hardens ultraviolet curable resin injected therein to form a resin molded product, The molding die is made of a fluororesin having a light transmittance of 50% or more and a water contact angle of 100° or more.

[0007] A method for molding an ultraviolet curable resin according to one embodiment of the present disclosure includes: A molding method for molding a gasket made of ultraviolet curable resin on a separator of a fuel cell, comprising: a step of bringing a forming die into contact with a flat separator; injecting an ultraviolet curable resin into a cavity through a gate provided in the molding die; a step of temporarily curing the ultraviolet curable resin injected into the molding die by irradiating the ultraviolet curable resin with ultraviolet light through the molding die; removing the separator having the temporarily cured ultraviolet curable resin from the molding die; and curing the ultraviolet curable resin on the separator removed from the mold by irradiating the ultraviolet curable resin with ultraviolet light, The molding die is made of a fluororesin having a total light transmittance of 50% or more and a water contact angle of 100° or more. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a molding die in which no ultraviolet curable resin remains in the gate portion, and a molding method for ultraviolet curable resin using the molding die. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic perspective view of a molding tool according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view of a molding die according to an embodiment of the present disclosure. [Figure 3] 1 is a flowchart illustrating a method for molding an ultraviolet curable resin according to an embodiment of the present disclosure. [Figure 4] 1A to 1C are diagrams illustrating a method for molding an ultraviolet curable resin according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, specific embodiments of the present disclosure will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. In addition, the following description and drawings have been simplified appropriately for clarity of explanation.

[0011] <Mold configuration> Fig. 1 is a schematic perspective view of a mold according to an embodiment of the present disclosure. Fig. 2 is a cross-sectional view of a mold according to an embodiment of the present disclosure. In the example of Fig. 2, a cross section II-II of the mold 1 shown in Fig. 1 is shown. The right-handed xyz Cartesian coordinate system shown in Figures 1 and 2 is for the sake of convenience in showing the positional relationships of the components. In Figures 1 and 2, the positive direction of the z axis is vertically upward, and the xy plane is the horizontal plane, which is common to all the drawings.

[0012] The molding die 1 includes a gate portion 2 that penetrates the molding die 1 in the z-axis direction, and a cavity portion 3 that is connected to the gate portion 2 and has a predetermined shape. The outer shape and size of the molding die 1 are not particularly limited. The molding die 1 shown in FIG. 1 is a molding die for molding a gasket made of an ultraviolet curing resin onto a separator 4 of a fuel cell shown in FIG. 4 (described later), and is a plate-like member that is rectangular in plan view, similar to the separator 4.

[0013] The material of molding die 1 preferably has a total light transmittance of 50% or more. By making the total light transmittance 50% or more, the ultraviolet-curable resin injected into cavity portion 3 will cure quickly when molding die 1 is irradiated with ultraviolet light. Here, the total light transmittance was measured by the measurement method specified in JIS K7375.

[0014] Furthermore, it is preferable that the material of casting mold 1 has a water contact angle of 100° or more. By making the water contact angle 100° or more, it is possible to remove all of the UV-curable resin that has hardened within gate portion 2. Here, the water contact angle is the contact angle between casting mold 1 and a droplet of water formed when the droplet is dropped onto casting mold 1, and was measured by the measurement method specified in JIS R3257.

[0015] The molding die 1 is made of, for example, a fluororesin. Examples of fluororesins include polytetrafluoroethylene, perfluoroalkoxyalkane, perfluoroethylenepropene copolymer, ethylenetetrafluoroethylene copolymer, polyvinylidene fluoride, polychlorotrifluoroethylene, and ethylenechlorotrifluoroethylene copolymer, with perfluoroalkoxyalkane and perfluoroethylenepropene copolymer being particularly preferred as fluororesins having a total light transmittance of 50% or more and a water contact angle of 100° or more.

[0016] Gate portion 2 is a small hole provided in mold 1 for injecting ultraviolet curable resin into cavity portion 3, and is connected to cavity portion 3. Note that, in FIGS. 1 and 2, gate portion 2 is a through-hole with a circular cross section that extends linearly in the z-axis direction, but it may also extend in a direction tilted from the z-axis direction. Also, in FIGS. 1 and 2, one gate portion 2 is connected to one cavity portion 3, but multiple gate portions 2 may be connected to one cavity portion 3. In other words, the shape, position, number of gate portions 2, and connection position with cavity portion 3 are not particularly limited. Here, the gate portion 2 shown in FIGS. 1 and 2 is a through-hole that extends linearly and has a circular cross section, so that the ultraviolet curable resin that has hardened within the gate portion 2 can be easily removed.

[0017] Furthermore, if the pores in the gate portion 2 are too large, the amount of UV-curable resin remaining in the gate portion 2 during injection molding will increase, reducing the yield of the UV-curable resin. Therefore, for example, it is preferable that the pore diameter is 3 mm or less and the pore length is 10 mm or less.

[0018] The cavity portion 3 has the same shape as the gasket to be molded. The cavity portion 3 is connected to the gate portion 2.

[0019] As explained above, the molding die according to the present disclosure is made of a fluororesin having a total light transmittance of 50% or more and a water contact angle of 100° or more. This configuration makes it possible to provide a molding die in which no ultraviolet curable resin remains in the gate portion.

[0020] <Ultraviolet curing resin molding method> Fig. 3 is a flowchart showing a molding method for ultraviolet curable resin according to an embodiment of the present disclosure. Fig. 4 is a cross-sectional view showing each step in the flowchart shown in Fig. 3. Note that the cross-sectional view of the molding die in Fig. 4 corresponds to the cross-sectional view of the molding die in Fig. 2.

[0021] The molding die 1 is made of a fluororesin having a total light transmittance of 50% or more and a water contact angle of 100° or more. A gasket made of ultraviolet curable resin is molded on the separator 4. At this time, the surface of the separator 4 may be roughened to improve the adhesiveness of the gasket. The separator 4 is, for example, a separator used in a fuel cell, and is made of carbon, stainless steel, or the like, but the material and size are not particularly limited.

[0022] The ultraviolet curable resin formed according to the present disclosure is not particularly limited, and any resin that is used as a resin material for gaskets can be used as appropriate, such as acrylic resin or epoxy resin.

[0023] 3 and 4, a molding die 1 is brought into contact with one surface of a separator 4 (step S1). Subsequently, an ultraviolet curable resin 5 is injected into a cavity 3 through a gate 2 provided in the molding die 1 (step S2).

[0024] 3 and 4, the ultraviolet curable resin 5 injected into the cavity portion 3 is irradiated with ultraviolet light via the molding die 1 to temporarily cure the ultraviolet curable resin 5 (step S3). The wavelength and intensity of the ultraviolet light irradiated onto the ultraviolet curable resin 5 are not particularly limited, and the irradiation time of the ultraviolet light is also not particularly limited.

[0025] 3 and 4, the separator 4 having the temporarily cured ultraviolet curable resin 5 is removed from the molding die 1 (step S4). At this time, the temporarily cured ultraviolet curable resin 5a in the cavity portion 3 is removed from the molding die 1 together with the separator 4 (integrated).

[0026] 3 and 4, the ultraviolet curing resin 5a temporarily cured on the separator 4 is irradiated with ultraviolet light to re-cure the ultraviolet curing resin 5a (step S5). In step S5, the resin is cured, and a gasket is formed on the separator 4.

[0027] The ultraviolet curable resin 5b temporarily cured within the gate section 2 in step S4 is removed from the gate section 2 in order to reuse the molding die 1 (step S6). By forming the molding die 1 from a fluororesin with a total light transmittance of 50% or more and a water contact angle of 100° or more, the ultraviolet curable resin 5b does not remain in the gate section 2 in step S6.

[0028] As described above, in the ultraviolet curable resin molding method according to the embodiment of the present disclosure, the molding die 1 is made of a fluororesin having a total light transmittance of 50% or more and a water contact angle of 100° or more. In other words, in the ultraviolet curable resin molding method according to the embodiment of the present disclosure, no ultraviolet curable resin remains inside the gate portion even if a release agent or coating is not applied to the gate portion.

[0029] <Example> Hereinafter, the present disclosure will be described in more detail with reference to examples and comparative examples, but the present disclosure is not limited to these examples.

[0030] Example 1 First, a mold made of PFA (perfluoroalkoxyalkane) was prepared, and a gate portion (diameter 1 mm, length 3 mm) and a cavity portion were provided in the mold. Next, the ultraviolet curable resin was molded based on the method for molding ultraviolet curable resin according to an embodiment of the present disclosure. Finally, it was checked whether or not the cured ultraviolet curable resin remained in the gate portion and the cavity portion.

[0031] Example 2 A molding die made of FEP (perfluoroethylene propene copolymer) was prepared, and similarly to Example 1, it was checked whether or not the ultraviolet curable resin remained.

[0032] (Comparative Example 1) A mold made of PMMA (polymethyl methacrylate) was prepared, and a gate and a cavity were provided in the mold, followed by a fluorine-based coating. Otherwise, similar to Example 1, a check was made to see if any UV-curable resin remained.

[0033] (Comparative Examples 2 and 3) A molding die made of PVDA (polyvinylidene fluoride) or ETFE (ethylene tetrafluoroethylene copolymer) was prepared, and the rest of the process was the same as in Example 1, and it was checked whether or not the ultraviolet curable resin remained.

[0034] [Table 1]

[0035] (Evaluation results) As shown in Table 1, in Examples 1 and 2, no ultraviolet curable resin remained in the cavity portion and the gate portion. In Comparative Example 1, no ultraviolet curable resin remained in the cavity portion, but ultraviolet curable resin remained in the gate portion. In Comparative Examples 2 and 3, the ultraviolet curable resin remained in the cavity and gate portions.

[0036] As explained above, by constructing the mold from a fluororesin with a total light transmittance of 50% or more and a water contact angle of 100° or more, it is possible to provide a mold in which no UV-curable resin remains in the gate area. [Explanation of symbols]

[0037] 1 mold 2 Gate section 3 Cavity 4 Separator 5, 5a, 5b UV curing resin

Claims

1. A molding die that transmits irradiated ultraviolet light and hardens ultraviolet curable resin injected therein to form a resin molded product, The molding die is made of a fluororesin having a total light transmittance of 50% or more and a water contact angle of 100° or more. Molding mold.

2. A plate-shaped member for molding a gasket made of ultraviolet curing resin onto a flat separator for a fuel cell, a gate portion penetrating the main surfaces; a cavity portion formed on a main surface that contacts the separator and connected to the gate portion; The mold according to claim 1 .

3. The gate portion is a through hole extending linearly and having a circular cross section. The mold according to claim 2 .

4. The gate portion extends in a direction perpendicular to the main surface. The mold according to claim 3 .

5. A molding method for molding a gasket made of ultraviolet curable resin on a separator of a fuel cell, comprising: a step of bringing a forming die into contact with a flat separator; injecting an ultraviolet curable resin into a cavity through a gate provided in the molding die; a step of temporarily curing the ultraviolet curable resin injected into the molding die by irradiating the ultraviolet curable resin with ultraviolet light through the molding die; removing the separator having the temporarily cured ultraviolet curable resin from the molding die; and curing the ultraviolet curable resin on the separator removed from the mold by irradiating the ultraviolet curable resin with ultraviolet light, The molding die is made of a fluororesin having a total light transmittance of 50% or more and a water contact angle of 100° or more. A method for molding ultraviolet curing resin.

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