KR20080111445A - Injection molding die - Google Patents

Abstract

An injection molding die in which an outer frame arranged depending on the shape at the circumferential edge of a plate molding can be fixed or replaced conveniently, and a high precision plate molding can be formed. The middle plate (30) of the injection molding die comprises a core plate (31) fixed removably to the substantially central position on the major surface (upper surface in the drawing) (11X) of a fixed mold plate (11), four outer frames (32) arranged contiguously to the outer circumference of the core plate (31), an outer circumferential support block (33) as an outer circumferential supporting frame fixed removably to the outer circumferential part on the side of the major surface (11X) of the fixed mold plate (11), and a locking block (34) as a member inserted between the outer frame (32) and the outer circumferential support block (33) on the side of the major surface (11X) of the fixed mold plate (11). The locking block (34) is formed to have an wedge-like (reverse trapezoidal) cross-section. ® KIPO & WIPO 2009

Description

Injection Mold Dies {INJECTION MOLDING DIE}

The present invention relates to a mold for injection molding. More specifically, the present invention relates to an injection molding die capable of simplifying the installation and replacement of the outer frame arranged according to the shape of the periphery of the flat molded article and forming a flat molded article with high precision.

Injection molded products are widely used from general purpose to precision applications such as daily necessities, automobile parts, home appliance parts, electronic parts, and optical devices. The quality and productivity of the injection molded product depends largely on the good and bad of the mold. The production of injection molding dies requires high technology in all aspects, such as work precision, quality uniformity and productivity.

Since the injection molding die has a relatively long delivery time and is expensive, the mold depreciation cost of the injection molded article is large. In addition, when the mold is replaced every time the molded article is changed, the labor and time loss are large, and the operation rate of the injection molding machine is reduced. Particularly, in flat plate molded products such as a light diffusion plate or a light guide plate used in a liquid crystal display device, even if a liquid crystal display device of the same size is used, the periphery (so-called ear) of the flat plate molded product may be changed due to the difference in the installation method of the device. Since the shapes are different, attempts have been made to form flat molded articles having different shapes and dimensions by using the same mold by preparing a plurality of kinds of outer frames having different shapes in the injection molding mold and replacing the outer frames.

For example, Japanese Unexamined Patent Application Publication No. 2004-188612 includes a core plate and an outer frame provided around the core plate, and the outer frame is configured such that a plurality of types having different width dimensions and shapes can be exchanged. Disclosed is a mold for injection molding which can arrange a plurality of kinds of flat liners having different dimensions between a plate and an outer frame. According to such an injection molding die, two or more kinds of flat molded articles having different effective areas can be formed by appropriately disposing a flat liner on the outer circumference of the core plate. Moreover, the external shape of a flat plate molded article can be changed by replacing the outer frame with a thing of a different shape.

Specifically, such an injection molding die has a configuration as shown in FIGS. 16 and 17, and can be assembled by the following procedure. It is sectional drawing which shows typically a part of structure of the conventional injection molding metal mold | die. 17 is an exploded cross-sectional view schematically showing a state of assembling an injection molding die. In the injection molding die shown in Figs. 16 and 17, the flat liner is not used.

As shown in FIG. 16, the conventional injection molding metal mold | die 100 is arrange | positioned at the substantially center position of the template 110 and the main surface 110X (upper surface in drawing) of the template 110. As shown in FIG. The plate 120, the outer frame 130 disposed on the outer circumference (right side in the drawing) of the core plate 120, and the outer circumferential support frame 140 disposed on the outer circumferential portion of the template 110 are provided.

The outer frame 130 is prepared with a plurality of types having different shapes. The outer frame 130 is installed on the main surface 110X of the template 110 by a bolt 101 extending substantially in parallel with the normal of the template 110, and at the same time approximately with respect to the main surface 110X of the template 110. It is provided in the outer peripheral part of the core plate 120 by the some bolt 102 extended in parallel.

The outer circumferential support frame 140 is formed with a recess 141 that fits to the positioning member 150 (pin or key) provided on the main surface 110X of the template 110. The outer circumferential support frame 140 is the main surface of the template 110 by a bolt 103 extending substantially parallel to the normal of the template 110 in a state where the positioning member 150 and the recess 141 are fitted. 110X).

The procedure of assembling the injection molding die 100 will be described.

As shown in FIG. 17, first, the core plate 120 is provided on the main surface 110X of the template 110, and then the outer frame 130 is disposed adjacent to the outer circumference of the core plate 120, and the bolt ( The outer frame 130 is attached to the template 110 by 101. At this time, a step is hardly generated between the upper surface 120X of the core plate 120 and the upper surface 130X of the cutout portion of the outer frame 130.

Next, while adjusting the tightening state between the plurality of bolts 102, the outer frame 130 is pressed against the core plate 120 side by these bolts 102. Next, the recess 141 of the outer circumferential support frame 140 is fitted to the positioning member 150 provided in the template 110, so that the outer circumferential support frame 140 is attached to the main surface 110X of the template 110. In this state, the outer circumferential support frame 140 is attached to the main surface 110X of the template 110 by the bolt 103.

However, in such an injection molding die 100, the tightening state between the plurality of bolts 102 to be executed when the outer frame 130 is pressed to the core plate 120 side is very complicated, and the outer frame ( The installation of 130 was complicated. In particular, when adjustment of the tightening state of these bolts 102 becomes inadequate, abrasion may generate | occur | produce in a flat plate molded article, and the precision of a flat plate molded article may fall. In addition, when the outer frame 130 is replaced with another shape, the outer support frame (from the template 110 is deliberately removed from the template 110 in order to loosen the bolt 102 extending substantially parallel to the main surface 110X of the template 110). There was also a problem that the work was complicated because the work had to be separated.

An object of the present invention is to provide an injection molding die which can simplify the installation and replacement of the outer frame arranged according to the shape of the periphery of the flat molded article, and can form a flat molded article with high precision.

In order to solve the above-mentioned problems and achieve the object, the injection molding die of the present invention has a fixed mold and a movable mold, and is an injection molding mold for forming a flat molded article. And each of the movable dies has a template, and is disposed adjacent to the outer circumference of the core plate and a core plate which is detachably installed on the main surface of any one of the stationary die and the movable die. An outer frame detachably attached to the main surface of A), an outer circumferential support frame detachably attached to the outer circumferential portion of the template A, and a main surface side of the template A, wherein the outer frame and the outer circumference. By pressing the insertion member inserted between the outer frame and the outer circumferential support frame and the insertion member to the main surface side of the template A in a state in contact with the support frame, And pressing means for pressing the outer frame toward the core plate side by the reaction force from the outer circumferential support frame. In addition, the direction in which the insertion member is inserted may be a direction perpendicular to the main surface of the template, or may be a direction parallel to the main surface of the template.

In the injection molding die of the present invention, the contact surface between the outer circumferential support frame and the insertion member can be inclined to the outer circumferential support frame side.

In the injection molding die of the present invention, the contact surface between the outer frame and the insertion member can be inclined to the outer frame side.

In the injection molding die of the present invention, the flat plate molded article can be an optical member.

In the injection molding die of the present invention, the optical member can be a light diffusion plate or a light guide plate made of a thermoplastic resin.

In the injection molding die of the present invention, the cavity surface of the core plate, the cavity surface of the stationary mold plate, and at least one cavity surface of the cavity surface of the movable mold plate are provided on the surface of the flat plate molded article. It can be set as the pattern formation part for providing a pattern shape.

In the injection molding die of the present invention, the flat plate is provided at a position corresponding to at least one cavity surface of the cavity surface of the core plate, the cavity surface of the stationary mold plate, and the cavity surface of the movable mold plate. The pattern forming member for giving a pattern shape to the surface of a molded article can be arrange | positioned.

Effects of the Invention

According to the injection molding die of the present invention, when the outer frame is provided in accordance with the shape of the periphery of the flat molded article, the insertion member is pressed by the pressing means between the outer frame and the outer support frame while in contact with the outer frame and the outer support frame. And the tightening state between bolts does not need to be adjusted as in the case of using a conventional bolt to press the outer frame to the core plate side with this insertion member, so that the installation work can be executed easily.

In addition, when replacing the outer frame, the outer frame can be released from the core plate side simply by taking out the insertion member, and since the outer circumferential support frame does not need to be removed on purpose, as in the prior art, the outer frame is replaced. You can easily run the job.

In addition, compared with the case where the outer frame is pressed to the core plate side by the plurality of bolts, the outer frame is pressed to the core plate side with the entire insertion member, so that the outer frame can be pressed to the core plate side with a uniform force. For this reason, the clearance gap between an outer frame and a core plate can be made uniform, and a high precision flat molded article without abrasion can be formed by this. Moreover, the compressed air blown from this clearance can be blown uniformly, and mold release of a flat plate molded article can be performed reliably.

1 is a schematic view showing a mold for injection molding according to an embodiment of the present invention;

2 is a schematic perspective view showing a main part of a mold for injection molding according to an embodiment of the present invention;

3 is a partial sectional view showing a main part of a mold for injection molding according to an embodiment of the present invention;

4 is a schematic partial sectional view showing the locking block and the outer support block;

5 is an exploded cross sectional view showing a main part of a mold for injection molding according to an embodiment of the present invention;

6 is a schematic perspective view showing an outer frame;

7 is a schematic plan view showing a fixed template;

8 is a schematic cross-sectional view showing a stationary template and a core plate;

9 is a schematic plan view showing a fixed template;

10 is a schematic cross-sectional view showing a stationary template and a core plate;

11 is a plan view showing a flat plate molded product;

12 is a plan view showing a flat plate molded product;

13 is a plan view showing a flat plate molded product;

14 is a schematic view for explaining an operation of molding a flat molded article using an injection molding die;

15 is a schematic view for explaining an operation of molding a flat molded article using an injection molding die;

16 is a partial cross-sectional view showing a main part of a conventional injection molding die;

17 is an exploded cross sectional view showing a main portion of a conventional injection molding die;

EMBODIMENT OF THE INVENTION Below, the injection molding die which concerns on embodiment of this invention is demonstrated in detail based on drawing. FIG. 1: is sectional drawing which shows typically the metal mold | die 1 for injection molding which concerns on this embodiment. As shown in Fig. 1, the injection molding die 1 is for forming a flat molded article made of a thermoplastic resin. The injection molding die 1 includes a stationary die 10 and a movable die 20 that can move back and forth with respect to the stationary die 10, and between the stationary die 10 and the movable die 20. The middle plate 30 provided in any one of 20 is provided.

The stationary die 10 includes a stationary plate 11, a stripper plate 12, a mounting plate 13 for mounting the stationary die 11 and the stripper plate 12 to a stationary side die plate (not shown) of an injection molding machine. ). The sprue 12A for injecting a thermoplastic resin is formed in the stripper plate 12 and the mounting plate 13. 11 A of runners and the gate 11B which communicate with 12 A of sprues are formed in the stationary template 11. The stationary die 11 is configured to be capable of moving forward and backward with respect to the stripper plate 12 and the mounting plate 13. The stripper plate 12 is configured to be capable of moving forward and backward with respect to the mounting plate 13. The movable die 20 includes a movable die 21 and a mounting plate 22 for mounting the movable die 21 on a movable side die plate (not shown) of the injection molding machine.

FIG. 2 is a schematic perspective view showing the middle plate 30 provided in the stationary template 11, and FIG. 3 is a partial cross-sectional view thereof. As shown in FIGS. 2 and 3, the middle plate 30 includes a core plate 31 detachably installed at a substantially central position of the main surface (upper surface in the drawing) 11X of the stationary template 11, and a core. Four outer frame 32 arranged adjacent to the outer circumference of the plate 31 and the outer circumferential support block 33 as the outer circumferential support frame detachably provided on the outer circumferential portion of the main surface 11X side of the fixed mold 11. And a locking block 34 as an insertion member inserted between the outer frame 32 and the outer circumferential support block 33 on the main surface 11X side of the fixed mold 11.

As shown in FIG. 3, the outer frame 32 has a shape in which a part of the rectangle vertices is cut into a rectangular shape, and the bolt extends substantially parallel to the normal of the fixing template 11 from the upper surface 32X side. By 4a, it is attached to the main surface 11X side of the fixed template 11 so that attachment or detachment is possible. At this time, the upper surface 32Y (that is, the surface one step lower than the upper surface 32A) of the cutout portion in the outer frame 32 is almost the same surface as the upper surface 31X of the core plate.

The outer circumferential support block 33 is formed in a trapezoidal cross section.

4 is an exploded cross-sectional view showing the locking block 34 and the outer circumferential support block 33. 3 and 4, the outer surface 33A, which is the surface of the outer circumferential side (right side in FIG. 4) in the outer circumferential support block 33, is a surface substantially perpendicular to the main surface 11X of the fixed template 11. The inner surface 33B, which is the surface on the side of the locking block 34 located on the side opposite to the outer surface 33A, is an inclined slope at an angle θ with respect to the outer surface 33A.

3, the recessed part 33C for positioning is formed in the lower surface 33Y of the outer peripheral support block 33. As shown in FIG. On the other hand, the convex positioning member 35 which protrudes upward in FIG. 3 is provided in the outer peripheral side of the main surface 11X of the stationary template 11. The outer circumferential support block 33 is positioned with respect to the stationary template 11 by fitting the recess 33C to the positioning member 35.

The outer circumferential support block 33 positioned as described above is detachably attached to the main surface 11X of the fixed mold 11 from the upper surface 33X side by a bolt 6a extending substantially parallel to the outer surface 33A. . At this time, the upper surface 33X of the outer circumferential support block 33 is at the same height position as the upper surface 32X of the outer frame 32.

The locking block 34 is formed in a cross-sectional wedge shape (inverted trapezoidal shape). Therefore, the contact surface of the outer circumferential support block 33 and the locking block 34 is inclined to the outer circumferential support block 33 side (outside) from the surface of which the upper side in FIG. 3 is substantially perpendicular to the main surface of the fixed template 11. .

3 and 4, the outer surface 34A, which is the surface on the outer circumferential support block 33 side of the locking block 34, is substantially parallel to the inner surface 33B, which is the inclined surface of the outer circumferential support block 33. As shown in FIG. The inner surface 34B, which is an inclined surface inclined at an angle θ, and which is a surface on the outer frame 33 side, is the main surface 11X of the fixed template 11 like the outer surface 32A of the outer frame 32. It is almost perpendicular to.

Here, the angle θ of the outer surface 34A of the locking block 34 and the inner surface 33B of the outer circumferential support block 33 is preferably in the range of 5 to 30 degrees, more preferably 10 to 20 degrees, 13-17 degree is more preferable. By setting the angle θ within these ranges, the outer frame 32 can be efficiently pressed against the core plate 31.

As shown in FIG. 3, when the locking block 34 is inserted between the outer frame 32 and the outer support block 33, the outer surface 34A of the locking block 34 becomes the outer support block 33. Is in contact with the inner side surface 33B, and the inner side surface 34B of the locking block 34 is in contact with the outer side surface 32A of the outer frame 32.

The locking block 34 is pressurized from the upper surface 34X side to the main surface 11X side of the fixed template 11 by the bolt 5a as a pressurizing means extending substantially parallel to the other bolts 4a and 6a. Is detachably attached to the stationary template (11).

The middle plate 30 can be assembled as follows. FIG. 5 is an exploded cross-sectional view showing a state in which the middle plate is disassembled in FIG. 3. As shown in FIG. 5, first, the core plate 31 is provided on the main surface 11X of the stationary template 11. Next, the concave portion 33C of the outer circumferential support block 33 is fitted to the positioning member 35 provided on the main surface 11X of the fixed die 11 to position the outer circumferential support block 33. In this state, the outer circumferential support block 33 is attached to the main surface 11X of the fixed mold 11 by the bolt 6a.

The Rockwell hardness (HRC: Japanese Industrial Standards JIS Z2245-2005C scale) of the locking block 34 is 100% to 20% compared to the hardness of the material of the outer frame 32 and / or the outer support block 33. It is preferable and it is more preferable that it is 80%-30%. If the Rockwell hardness of the rocking block 34 is greater than 100%, the outer frame 32 or the like may be damaged and the precision may be lowered. If the rockwell hardness of the rocking block 34 is less than 20%, the function of the rocking block 34 may be insufficient, resulting in insufficient durability. There is a risk of falling.

Moreover, the surface roughness in the outer surface 34A used as the contact surface of the outer peripheral support block 33 in the locking block 34, and the inner surface 34B used as the contact surface of the outer frame 32 is a thing of each contact surface. It is preferable that arithmetic mean roughness Ra is 0.02 micrometer (mirror surface)-200 micrometers, and 0.1-100 micrometers is more preferable. When the arithmetic mean roughness of a contact surface is less than 0.02 micrometer, there exists a possibility that the friction force between a contact surface may become large and separation of the locking block 34 may become difficult. On the other hand, when the arithmetic mean roughness of a contact surface is larger than 200 micrometers, there exists a possibility that the positioning precision between members may fall, and durability may fall.

In general, grease or the like is easily separated between the members. However, when the molded article is an optical member, grease cannot be used since grease adheres to the molded article, which may be a defective product. Instead, the surface roughness of each member is controlled as described above.

Next, the outer frame 32 is arrange | positioned adjacent to the outer periphery of the core plate 31, and the outer frame 32 is attached to the main surface 11X of the fixed template 11 with the bolt 4a. At this time, a step does not occur between the upper surface 31X of the core plate 31 and the upper surface 32Y of the cutout portion of the outer frame 32.

Next, the locking block 34 is inserted between the outer frame 32 and the outer circumferential support block 33, and the inner surface 34B of the locking block and the outer surface 32A of the outer frame 32 are brought into contact with each other. Further, the outer surface 34A of the locking block and the inner surface 33B of the outer circumferential support block 33 are brought into contact with each other. By tightening the bolt 5a in this state, the locking block 34 is pressed toward the main surface 11X side of the stationary template 11. When the locking block 34 is pressurized by tightening the bolts 5a in this manner, the surfaces 34A and 33B and the surfaces 34B and 32A are in contact with each other, and the locking block 34 moves to the stationary plate 11 side. . At this time, by the reaction of the inner surface 34A of the locking block 34 pressing the outer surface 33B of the outer circumferential support block 33, the locking block 33 causes the outer frame 32 to move to the core plate ( 31) to the side. In this state, the locking block 34 is provided on the main surface 11X side of the fixed template 11.

Thus, while the locking block 34 presses the outer frame 32 toward the core plate 31 side, the inner block 33B of the outer circumferential support block 33 is pressed against the entire outer surface 34A of the locking block 34. Therefore, the locking block 34 can press the outer frame 32 toward the core plate 31 side with a uniform force along the longitudinal direction of the outer frame 32. For this reason, the clearance gap between the core plate 31 and the outer frame 32 can be made uniform, and it can suppress that abrasion etc. generate | occur | produce in a flat plate molded article.

By the way, as shown in FIG. 6, the notch part 32P is formed in the inner side surface 32B which is the surface of the core plate 31 side in the outer frame 32. As shown in FIG. A blower 32S is provided adjacent to the cutout 32P, and guides compressed air which is release air for releasing the molded flat plate molded product from the core plate 31 to the cutout 32P. In the notch part 32P, since compressed air is blown uniformly, mold release and take-out of the molded flat plate molded article become very easy.

In addition, the upper surface 32X of the outer frame 32 is provided with a groove portion 32U for discharging gaseous thermal decomposition products that can be produced from the molten resin when forming the flat molded article. Thereby, foam etc. can be prevented from occurring in a flat plate molded article, and the precision of a molded article can be improved.

By the way, as shown to FIG. 7 thru | or 10, the key 36 can be used as a positioning member in order to prevent the position shift of the core plate 31 and the fixed mold | board 11. FIG. When arranging such a key 36, the key 36 expands or contracts in the back when either the member of the core plate 31 or the stationary template 11 is first heated and expanded or cooled and contracted. It is preferable to have a structure which can avoid thermal expansion and thermal contraction so that a distortion etc. do not arise in the other member. As such a structure, for example, as shown in FIG. 7 and FIG. 8, the key 36 is disposed in the groove 11C formed at one point in the center of the stationary template 11, and at this point, the core plate 31 is provided. It can be made to support the structure.

9 and 10, the positioning member is composed of the keys 36 and 37, and the key 36 is disposed in the groove 11C at one point in the center of the fixed template 11, The rectangular key 37 may be disposed in the groove 11D formed in the radially symmetrical position extending from one direction in the one direction and the other direction opposite to the one direction from the center. That is, it can be set as the structure which provided the groove | channel 11D which extends in parallel with the said one and the other direction by the dimension larger than the key 37 between the stationary template 11 and the core plate 31. FIG. Therefore, since the dimension of the groove 11D is longer than the dimension of the radiating portion key 37 in the longitudinal direction of the stationary template 11, either one of the core plate 31 or the stationary template 11 is expanded. Or even if it shrinks, these thermal expansion and thermal contraction can be avoided, and distortion, etc. can be prevented.

Next, the case where the outer frame 32 is separated will be described. For example, flat shaped articles, such as a light diffusion plate and a light guide plate, used for a liquid crystal display device, even if they have the same dimensions, differ in the shape of the periphery of the flat molded article and the so-called ear shaped section due to differences in the installation method in the apparatus. For example, as shown in FIGS. 11-13, the shape of the periphery part differs in flat molded articles 24a-24c. For such flat molded articles 24a to 24c, the same core plate 31 is used and the outer frame 32 is replaced according to the shape of the periphery, thereby forming flat molded articles 24a to 24c having different shapes. can do.

In order to replace the outer frame 32, in FIG. 3, the locking block 34 is first detached from the stationary template 11 by loosening the bolt 5a. At this time, since the pressurization from the locking block 34 to the outer frame 32 is released, the bolt 4a can be simply loosened. For this reason, only the bolt 4a is loosened, and the outer frame 32 can be easily detached from the fixed template 11, without removing the outer support block 33 from the fixed template 11. Therefore, in the injection molding die 1 of the present embodiment, since the outer frame 32 can be separated only by removing the locking block 34, the outer frame 32 can be easily replaced, and the work can be performed. It's easy.

Next, the procedure for forming a flat molded article using the injection molding die 1 will be described. 14 and 15 are schematic diagrams for explaining an operation of molding a flat molded article using an injection molding die. As shown in FIG. 1, first, in a state in which the stationary die 10 and the movable die 20 are closed, the thermoplastic resin in the molten state is injected from above the mounting plate 13, and the sprue 12A and the runner ( The molten resin is filled into the cavity via 11A) and gate 11B.

Next, after the molten resin is cooled and solidified, as shown in FIG. 14, the movable die 20 is retracted to open between the movable die 21 and the middle plate 30, and the flat molded article X is opened. Expose Next, as shown in FIG. 15, the movable template 21 is further retracted to open between the stationary template 11 and the stripper plate 12, and the thermoplastic resin of the pin point gate portion is cut off.

Moreover, the compressed air which is mold release air is blown out from the cutout part 32P of the outer frame 32 shown in FIG. 6, and the flat plate molded object X is mold-released from the middle plate 30, and is taken out. Finally, the parts corresponding to the sprue 12A, the runner 11A, and the gate 11B are taken out by a robot or the like, and then the movable mold 20 and the fixed mold 10 are closed to complete one cycle of injection molding. do. As described above, a flat molded article can be obtained.

In the case of shifting to the manufacture of flat molded articles having different shapes or dimensions of the peripheral part, after removing the outer frame 32 used in the above-described procedure, the outer frame corresponding to the shape of the peripheral part of the flat molded article is described in the above-described order. Replace with (32).

Although there is no restriction | limiting in particular as a flat plate molded article shape | molded using the injection molding metal mold of this invention, It can apply suitably to the flat plate molded article which requires strict planarity on the surface, Especially an optical member is preferable. The optical member includes a light diffusing plate, a light guide plate, a reflecting plate, a writing curtain, a fresnel lens, a lenticular lens, and the like. The material of the optical member is preferably a thermoplastic resin, and a thermoplastic compound containing a light diffusing agent. Resin can also be used. Although there is no restriction | limiting in particular as a thermoplastic resin, For example, methacryl resin, polycarbonate, polystyrene, acrylonitrile-styrene copolymer resin, methyl methacrylate methyl-styrene copolymer resin, resin which has alicyclic structure, aromatic vinylic monomer, The copolymer of the (meth) acrylic-acid alkyl type monomer which has a lower alkyl group, polyether sulfone, etc. are mentioned.

Among them, copolymers of a resin having an alicyclic structure and an aromatic vinyl monomer and a (meth) acrylic acid alkyl monomer having a lower alkyl group can be suitably used, and a resin having an alicyclic structure can be particularly suitably used. Since the resin having an alicyclic structure has good flowability of the molten resin, the pin point gate can be used to fill the cavity of the mold, and the hygroscopicity is extremely low, so the dimensional stability is excellent, and the flat molded part is not likely to be warped. Since the specific gravity is small, the flat molded article can be reduced in weight. In addition, (meth) acrylic acid is methacrylic acid and acrylic acid.

In addition, this invention is not limited to the said embodiment, A various correction and a change can be implemented in this claim and an equivalent range.

For example, the injection molding die 1 is constituted of three plates of the stationary template 11, the movable template 21, and the middle plate 30, but any one of the stationary template 11 and the movable template 21 is formed. It is good also as a structure which consists of two plates provided with the middle plate 30 in one side.

The fixed mold 11 may be a hot runner having a heating mechanism therein or a cold runner having no heating mechanism.

Further, a pattern forming member for forming a predetermined pattern shape on the surface of the flat plate molded article, for example, a stamper of a thin plate on which a pattern is formed, may be used on any one of the cavity surface of the movable template 21 and the cavity surface of the stationary template 11. You may arrange | position in a position corresponded to a surface. The pattern forming member may be disposed on the cavity surface of the core plate 31. In addition, you may directly form the pattern formation part for forming a predetermined pattern shape in either surface of the cavity surface of the movable template 21 and the cavity surface of the stationary template 11. The pattern forming portion may be directly formed on the cavity surface of the core plate 31. By arranging such a pattern forming member or by providing a pattern forming portion, a desired pattern shape can be formed on the surface of the molded article simultaneously with molding the flat molded article, so that the number of steps can be reduced as compared with the case where a pattern shape is separately formed. have.

Here, the said pattern shape is a concave-convex shape which diffuses and exits the incident light by forming on the surface of this light-diffusion plate, for example, when a flat molded article is a light-diffusion plate. As a specific shape of a pattern shape, it can be set as uneven | corrugated shape, such as the shape of a polygonal cross-sectional shape or a semi-circular cross-section, and the linear part extended in a linear form substantially arranged in parallel in plurality. Examples of the polygons include triangles and squares. The semi-circular shape includes, in addition to a semicircle, a semi-elliptic shape, a shape having a curved portion in part. Moreover, as a pattern shape, it can be set as uneven | corrugated shape, such as a polygonal pyramid (triangular pyramid, a square pyramid, etc.), and a hemisphere shape (a shape which has a curved surface in a part of hemispherical, semi-elliptic sphere, parabolic surface, etc.). Moreover, although the case where these uneven | corrugated shapes were formed in the surface of a light-diffusion plate was demonstrated, you may form the said uneven | corrugated shape on the surface of flat plate molded goods other than a light-diffusion plate.

In addition, in the above-mentioned embodiment, although the pressurization of the locking block 34 to the stationary template 11 side is performed by tightening the bolt 5a, pressurization by other pressurization means, such as hydraulic pressure and a spring, for example. You may also Moreover, the longitudinal cross-sectional shape of the locking block 34 is not limited to the cross-sectional wedge shape mentioned above, As long as it is a shape which can press the outer frame 32 to the core plate 31 side, it may be another shape. In addition, the shape and dimensions of the cutout portion 32P described above are not particularly limited, and the compressed air may be ejected uniformly.

In addition, in the above-mentioned embodiment, the case where the contact surface of the outer peripheral support block 33 and the locking block 34 was inclined at the outer peripheral support block 33 side was demonstrated, but the outer frame 32 and the locking block 34 were not described. May be inclined to the outer frame 32 side. In addition, the contact surface of the outer circumferential support block 33 and the locking block 34 is inclined to the outer circumferential support block 33 side, and at the same time, the contact surface of the outer frame 32 and the locking block 34 is placed on the outer frame 32 side. It may be inclined. In these cases, the inclination angle of the contact surface of the outer frame 32 and the locking block 34 can be in a suitable range such as the angle of the contact surface of the outer circumferential support block 33 and the locking block 34. Specifically, the inclination angle is preferably in the range of 5 to 30 degrees, more preferably 10 to 20 degrees, and more preferably 13 to 17 degrees. In addition, in the contact surface between the outer frame 32 and the locking block 34, the hardness, surface roughness, and the like of the outer surface 32A of the outer frame 32 and the inner surface 34B of the locking block 34 may be determined. It can be set as the suitable range, such as hardness and surface roughness of the contact surface of the support block 33 and the locking block 34. As shown in FIG. In this way, even when the outer frame 32 and the locking block 34 in which the contact surface of the outer frame 32 and the locking block 34 are inclined to the outer frame 32 side are used, the locking block ( By pressing 34 to the main surface side of the stationary template 11, the outer frame 32 can be pressed to the core plate 31 side by the reaction force from the outer circumferential support block 33.

As described above, the injection molding die according to the present invention can quickly replace the outer frame by a simplified operation when the outer frame is replaced according to the shape of the periphery of the flat molded article. It is useful for the injection molding die. In particular, it is suitable for shaping flat molded articles, such as a light-diffusion plate, a light guide plate, and a reflecting plate which require rigid flatness.

Claims (7)

In the mold for injection molding having a fixed mold and a movable mold, and for forming a flat molded article, The fixed type and the movable type each have a template, A core plate detachably provided on a main surface of the template A of either the fixed mold or the movable mold; An outer frame disposed adjacent to an outer circumference of the core plate and detachably installed on a main surface of the template A; An outer circumferential support frame detachably installed on an outer circumferential portion of the template A, On the main surface side of the template (A), an insertion member inserted between the outer frame and the outer circumferential support frame in contact with the outer frame and the outer circumferential support frame, And pressing means for pressing the outer frame toward the core plate by reaction force from the outer circumferential support frame by pressing the insertion member toward the main surface side of the template A. Injection Mold. The method of claim 1, The contact surface between the outer circumferential support frame and the insertion member is inclined toward the outer circumferential support frame. Injection Mold. The method of claim 1, The contact surface between the outer frame and the insertion member is inclined toward the outer frame side. Injection Mold. The method of claim 1, The flat plate molded article is an optical member Injection Mold. The method of claim 4, wherein The optical member is a light diffusion plate or a light guide plate made of a thermoplastic resin, characterized in that Injection Mold. The method of claim 1, On the cavity surface of the core plate, the cavity surface of the stationary mold plate, and at least one cavity surface of the cavity surface of the movable mold plate, a pattern forming portion for providing a pattern shape to the surface of the flat plate molded article is formed. Characterized in that Injection Mold. The method of claim 1, For imparting a pattern shape to the surface of the flat plate molded article at a position corresponding to the cavity surface of the core plate, the cavity surface of the stationary mold plate, and at least one cavity surface of the cavity surface of the movable mold plate. The pattern forming member is disposed, characterized in that Injection Mold.

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