KR20130014149A - Mold structure for forming of ultraviolet curable resin - Google Patents

Abstract

PURPOSE: The mold for a UV curable acrylate molding is provided to minimize shrinkage by hardening shrinkage, and to reduce failure rate of a product by reducing component tolerance which is cause by hardening shrinkage. CONSTITUTION: The mold for a UV curable acrylate molding comprises a top mold(30) and a bottom mold(40). A transmitting window(31) which ultraviolet ray is transmitted is mounted at the top mold. The bottom mold is located in the lower part of the top mold and is combined in the top mold. The top mold and the bottom mold have a dual structure which is formed as the outer mold and intra mold of the different material.

Description

Mold structure for forming of ultraviolet curable resin

The present invention relates to a mold structure for forming an ultraviolet curable resin, and more particularly, to a mold structure for forming an ultraviolet curable resin that can compensate for shrinkage of the resin during curing to minimize the tolerance of the molded product.

In general, the ultraviolet curable resin has an unsaturated group component such as vinyl group in the resin molecular structure, and when the ultraviolet rays are received, it means that the resin is cured by crosslinking and polymerizing through the initiation reaction of free radicals. In general, the thermosetting method does not use a material that is deformed at a high temperature, and there is a problem in that a high energy consumption is required in the curing process, but a high cost is required. Productivity has an advantage.

Figure 1 schematically shows a conventional ultraviolet curing resin molding apparatus. Referring to FIG. 1, a cavity 5 corresponding to a shape of a molding is formed in a mold 3 in which a light transmission window 1 is formed, and an ultraviolet irradiator 7 is positioned above the mold 3. The ultraviolet irradiator 7 is located in the bell hood 8, and a gas supply pipe 9 for supplying an inert gas or the like is connected to the hood 8. Although not shown, a die or chamber on which the mold 3 is mounted, a chuck for fixing the mold 3, a moving means for moving the ultraviolet irradiator 7 in the vertical direction and the horizontal direction may be further added.

In the ultraviolet curable resin molding apparatus as described above, after injecting a liquid ultraviolet curable resin into the mold (3), the resin corresponding to the shape of the cavity (5) when irradiated with an appropriate amount of ultraviolet light in the ultraviolet irradiator (7) for a predetermined time The molding is molded.

However, shrinkage occurs in the process of curing the ultraviolet curable resin, the dimensional tolerance of the final molding is caused by this curing shrinkage. Such a dimensional tolerance causes a failure rate of components such as a lens mounted in a miniature imaging module, and increases the yield.

The present invention is to cure the shrinkage occurs after the physical shrinkage of the UV-curable resin by having a mold in a double structure so as to generate a mechanical shrinkage by applying a mechanical pressure to the mold in which the resin is accommodated before the curing of the UV-curable resin, It is an object of the present invention to provide a mold structure for forming a UV curable resin which can minimize shrinkage due to curing, greatly reduce tolerance due to curing shrinkage, and reduce product defect rate.

In the mold structure for forming an ultraviolet curable resin according to an embodiment of the present invention, in the mold structure for forming an ultraviolet curable resin for molding an ultraviolet curable resin contained therein into a resin molding having a predetermined shape, ultraviolet rays are transmitted. An upper mold having a light transmission window; And a lower mold positioned below the upper mold and coupled to the upper mold, wherein the upper mold and the lower mold each have a double structure formed of an outer mold and an inner mold of different materials.

In the mold structure for forming a UV curable resin according to another embodiment of the present invention, the inner mold is formed of a soft material compared to the outer mold.

In the mold structure for forming a UV curable resin according to another embodiment of the present invention, at least one of the upper mold and the lower mold has a stepped portion in which the end of the inner mold protrudes compared to the end of the outer mold. do.

In the mold structure for UV-curable resin molding according to another embodiment of the present invention, both the upper mold and the lower mold are protruded from the end of the inner mold compared to the end of the outer mold to form a step.

According to the mold structure for forming the UV-curable resin of the present invention, the mold is separated up and down, and the upper mold and the lower mold are dual structures of the inner mold and the outer mold, respectively, so that the inner mold when mechanical pressure is applied to the outer mold Ultraviolet curing proceeds after the first physical shrinkage occurs due to the elastic change, thereby minimizing the shrinkage rate of the hardened porridge, which is the secondary shrinkage in the curing stage, and reducing component tolerances due to hardening shrinkage. As the product defect rate is reduced, the yield can be improved.

1 is a cross-sectional view schematically showing a conventional ultraviolet curing resin molding apparatus,
2 is a cross-sectional view schematically showing an ultraviolet curing resin molding apparatus to which a mold structure according to the present invention is applied, and
3A and 3B are cross-sectional views illustrating examples in which mechanical pressure is applied to a mold.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the same or corresponding components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted.

2 is a cross-sectional view schematically showing an ultraviolet curing resin molding apparatus to which a mold structure according to the present invention is applied. Prior to the description of the mold structure with reference to Figure 2 will be briefly described for the ultraviolet curable resin molding apparatus to which the mold structure of the present invention is applied.

The ultraviolet irradiator 10 is installed above the chamber 20. As an example, the ultraviolet irradiator 10 is located in a bell-shaped hood 12, and a gas supply pipe 14 for supplying an inert gas or the like is connected to the hood 12. The kind of gas supplied into the hood 12 is selected according to the composition of an ultraviolet curable resin. Although not shown, a moving mechanism for moving the ultraviolet irradiator 10 in a horizontal direction and a vertical direction may be further included.

The chamber 20 has a box shape in which an upper portion thereof is opened to allow ultraviolet light to enter therein, and a wall surface of the chamber 20 is formed of a light blocking material to trap the light emitted from the ultraviolet irradiator 10 therein. In addition, a light reflection material may be coated on the inner wall surface of the chamber 20. An upper plate 22 made of a light transmissive material is installed in the upper portion of the chamber 20 to transmit light from the ultraviolet irradiator 10. Top plate 22 is, for example, a glass panel or an acrylic panel.

As shown in FIG. 2, the upper mold 30 and the lower mold 40 are spaced apart from each other, and are configured to be coupled by an ultraviolet curable resin molding apparatus.

The upper mold 30 is fixedly installed on the upper plate 22. The upper mold 30 may be fixed to the upper plate 22 by a fixing bracket or the like by a vacuum suction device (not shown).

The lower mold 40 is positioned below the upper mold 30 to be spaced apart from the upper mold 30. The lower mold 40 is fixedly installed on the fixed chuck 24, and the fixed chuck 24 is driven up and down by the lifting driving means 26 in the chamber 20. The lifting driving means 26 is, for example, a hydraulic cylinder or a pneumatic cylinder. As another example, the elevating driving means 26 may be a rod that performs linear reciprocation by a linear motor.

In the example shown, the cavity 50 inside the upper mold 30 and the lower mold 40 is depicted as being rectangular. However, when molding a molded product having a three-dimensional shape, such as a lens, the upper mold 30 is formed to be concave to correspond to the upper surface of the molding, and the lower mold 40 is formed to be concave to correspond to the lower surface of the molding.

Referring to FIG. 2, the upper mold 30 includes a light transmitting window 31 so that ultraviolet rays may be irradiated onto the liquid ultraviolet curable resin accommodated therein. And, according to a preferred embodiment, the upper mold 30 has a double structure formed of the outer mold 32 and the inner mold 34 of different materials. In this case, the inner mold 34 is formed of a soft material compared to the outer mold 32. For example, the upper mold 32 may be formed of metal, and the lower mold 34 may be formed of soft plastic.

The light transmission window 31 may be formed throughout the upper mold 32 and the lower mold 34. As another example, as shown in FIG. 2, a part of the upper mold 32 is transparently formed or made of glass, acrylic, or the like to form the transparent window 31, and the lower mold 34 is formed of a light-transmissive soft plastic. May be

Like the upper mold 30, the lower mold 40 also has a double structure of the outer mold 42 and the inner mold 44 of different materials. The material of the outer mold 42 and the inner mold 44 of the lower mold 40 is the same as that described for the upper mold 30.

Preferably, at least one of the upper mold 30 and the lower mold 40 has an end of the inner mold 34, 44 protruding from the ends of the outer mold 32, 42, as depicted in FIG. 2. Steps 36 and 46 are formed as shown. Alternatively, as illustrated, the step 36 and 46 may be formed at the ends of the inner molds 34 and 44 in both the upper mold 30 and the lower mold 40.

When the steps 36 and 46 are formed in this manner, the inner molds 34 and 44 are engaged with each other as shown in FIG. 3A to prevent the external outflow of the ultraviolet curable resin, and as shown in FIG. 3B. The molds 32 and 34 may be engaged to apply mechanical pressure to the inner molds 34 and 44 and to physically contract before curing the ultraviolet curable resin.

Here, in the illustrated example, the gap between the outer molds 32 and 42 generated between the steps 36 and 46 is shown as large as possible to aid the understanding of the invention. In practice, however, this gap is so small that such elastic deformation does not affect the appearance of the molding when elastic deformation of the inner molds 34 and 44 is generated by a process such as FIG. 3B.

Meanwhile, in the illustrated device configuration, the ultraviolet irradiator 10 is positioned above and the chamber 20 is positioned below, but this positional relationship is merely an example to help understanding of the present invention. For example, contrary to the configuration of FIG. 2, the UV irradiator 10 may be located at the bottom and the chamber 20 may be located at the top. In this case, the up and down relationship of the mold may be located at the bottom of the mold having the light transmission window of the mold. It will be configured in reverse.

Hereinafter, a process of curing and molding an ultraviolet curable resin in an ultraviolet curable resin molding apparatus using the mold structure of the present invention will be described with reference to the illustrated examples.

First, a liquid ultraviolet curable resin is injected or applied into the lower mold 40. At this time, the volume of the ultraviolet curable resin is larger than the volume of the desired molding in consideration of the primary physical shrinkage caused by the elastic deformation of the inner molds 34 and 44.

Next, the elevating driving means 26 is operated to engage the upper and lower inner molds 34 and 44 with each other as shown in FIG. 3A. In this case, the injection of the ultraviolet curable resin may be performed after the engagement between the inner molds 34 and 44 as shown in FIG. 3A. In this case, although not shown, an injection tube for injecting the ultraviolet curable resin into the mold is used.

Next, the elevating driving means 26 is operated to engage the upper and lower outer molds 32 and 42 with each other as shown in FIG. 3B. At this time, the elastic deformation occurs at the stepped portions 36 and 46 of the inner molds 34 and 44 by the mechanical pressure of the elevating driving means 26, and physical shrinkage is applied to the ultraviolet curable resin therein.

Subsequently, when the ultraviolet light irradiator 10 irradiates an appropriate amount of ultraviolet light for a predetermined time, the final resin molding is molded. In addition, the resin molding may be cured after the primary physical shrinkage, thereby minimizing shrinkage due to curing. That is, it means that the shrinkage of the volume of the final resin molding is insignificant compared to the volume of the resin due to the primary physical shrinkage.

Here, the application of mechanical pressure as in FIG. 3b occurs before curing, and 'before curing' means before the time when the curing is completely finished. For example, after the start of hardening at which irradiation of ultraviolet rays starts, the lifting driving means 26 may be raised to apply mechanical pressure to the mold to proceed with primary shrinkage. In other words, physical shrinkage may be performed during the curing process.

The present invention is not limited to the above-described embodiments and the accompanying drawings, and it is common knowledge in the technical field of the present invention that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be apparent to those who have

10: ultraviolet irradiator 12: hood
14 gas supply pipe 20 chamber
22: upper plate 24: fixed chuck
26: lifting drive means 30: upper mold
31 floodlight 32 outer mold
34: internal mold 36: step
40: lower mold 42: outer mold
44: internal mold 46: step
50: cavity

Claims (4)

In the mold structure for UV cure resin molding for shape | molding the ultraviolet cure resin accommodated inside by the resin molding of a predetermined shape,
An upper mold having a light transmitting window through which ultraviolet rays are transmitted; And
A lower mold positioned below the upper mold and coupled to the upper mold;
The upper mold and the lower mold is a mold structure for forming a UV curable resin, each having a double structure formed of an outer mold and an inner mold of different materials.
The method of claim 1,
The inner mold is a mold structure for forming a UV curable resin formed of a soft material compared to the outer mold.
The method according to claim 1 or 2,
At least one of the upper mold and the lower mold has a mold structure for forming a UV curable resin, wherein an end of the inner mold protrudes to form a step compared to an end of the outer mold.
The method according to claim 1 or 2,
Both the upper mold and the lower mold is a mold structure for forming a UV curable resin in which the end of the inner mold protrudes to form a step compared to the end of the outer mold.

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