JP3498640B2 - Manufacturing method of thermosetting synthetic resin molded product - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a thermosetting synthetic resin molded article.

[0002]

2. Description of the Related Art Conventionally, in the production of thermosetting synthetic resin moldings such as bathtubs, wash-basins, and counters,
As shown in FIG. 3, a pressure tank for injection containing a molding material 5 containing a thermosetting synthetic resin as a main component, which is obtained by adjusting a raw material, in a gap between a lower mold part and an upper mold part of the mold. 8 injection hose 9
Is connected to an injection part 7 communicating with the gap 4 provided in the molding die 1, and air pressure is applied to the injection pressure tank 8 so that the molding material 5 in the injection pressure tank 8 is injected from the injection part 7 to the molding die. 1 is injected into the gap 4 between the lower mold part 2 and the upper mold part 3 (the injection pressure is, for example, 1 to 1.5 kgf / cm ² ), after which the injection of the molding material 5 is stopped and the injection part 7 is The molding material 5 which was closed and poured into the gap 4 was molded by the molding die 1. However, if molding is performed with the clearance of the gap 4 kept constant, the molding material 5 containing a thermosetting compatible resin as a main component cures and shrinks, so that it cannot be molded into an accurate shape. Therefore, in the conventional case, the air bag 20 is interposed between the lower mold part 2 and the mounting plate, and the pressure of the air bag 20 is set to 0 kg during mold matching (before injecting the molding material 5).
As shown in FIG. 4 (a), the clearance dimension L in the portion A of the gap 4 is set to 13 to 14 mm as f / cm ² , and when the injection of the molding material 5 into the gap 4 is completed, the airbag 2
The pressure of 0 is set to 1 to 1.5 kgf / cm ² in FIG.
The dimension L of the clearance in the A portion of the gap 4 is set to 11.5 to 12 mm as shown in FIG. 2 to correspond to the curing shrinkage of the molding material 5 containing the thermosetting synthetic resin as the main component and corresponding to the airbag 2.
The lower mold part 2 is followed by 0, and the pressure of the airbag 20 is set to 5.5 kgf / cm ² at the time of completion of molding, as shown in FIG.
As shown in, the clearance was adjusted by the pressure control of the airbag 20 so that the dimension L of the clearance in the A portion of the gap 4 was 10 mm.

However, since the rising portion of the molded product indicated by B in FIG. 3 is not orthogonal to the direction in which the pressure is applied by the air bag 20, the rising portion of the thermosetting synthetic resin molded product indicated by B shows the air. Back 20
Is not applied sufficiently, and defective molding such as unevenness occurs.

Therefore, it is necessary to open the molding die 1 and take out the thermosetting synthetic resin molded product, and then to reinforce the defective molding portion generated in the portion B by FRF.

Further, in the prior art, since the lower mold part 2 is moved by the pressure adjustment by the air bag 20 during molding, the periphery of the gap 4 between the lower mold part 2 and the upper mold part 3 is sealed. The pressure of the airbag 20 is also applied to the sealing material 6, and the thickness of the sealing material 6 changes during molding. As a result, when the number of times of use increases, the sealing material 6 deforms (sets) and thermosetting synthetic resin molding. The plate thickness of the product may vary.

As described above, in the conventional example, the clearance is adjusted by controlling the pressure of the airbag 20, and the lowering of the airbag 20 is performed in response to the curing shrinkage of the molding material 5 containing the thermosetting synthetic resin as the main component. There is a problem that it is necessary to follow the mold part 2 and the manufacturing becomes complicated, and furthermore, there is a problem that a correction step of reinforce the defective molding part by FRF after molding is necessary.
There is a problem that the sealing material 6 is deformed (sets) and the thickness of the thermosetting synthetic resin molded product also varies.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and can be molded without changing the clearance during molding to simplify the manufacturing, and
A thermosetting synthetic resin molded product that can be molded accurately by a simple method without the need for post-correction steps, the sealing material does not deform, and the plate thickness of the thermosetting synthetic resin molded product can be kept constant. It is an object of the present invention to provide a method for manufacturing the same.

[0008]

In order to solve the above problems, a method for producing a thermosetting synthetic resin molded article according to the present invention is
The gap 4 between the lower mold part 2 and the upper mold part 3 of the molding die 1 is set to be the same as the thickness of the final molded product, and while maintaining this setting, thermosetting synthesis is performed in the gap 4. A molding material 5 containing a resin as a main component is injected, and after the injection is completed, the injection pressure is continuously applied to the gap 4 to continuously mold the molding material 5 containing a thermosetting synthetic resin as a main component. It is a thing. By adopting such a method, the molding material 5 shrinks during molding of the molding material 5 containing the thermosetting synthetic resin as the main component by the molding die 1. The material 5 is injected under pressure, so that there is no unevenness in the wall thickness due to shrinkage at the stage of the final molded product,
Therefore, it is possible to manufacture a thermosetting synthetic resin molded product having no irregularities. Since the gap 4 between the lower mold part 2 and the upper mold part 3 of the molding die 1 is set to be the same as the thickness of the final molded product, and the subsequent molding is performed with this setting maintained, Unlike the conventional case, it is not necessary to follow the lower mold part 2 with an air bag in response to the curing shrinkage of the molding material 5 mainly composed of a thermosetting synthetic resin.

Further, a temperature difference is made between the lower mold part 2 and the upper mold part 3 at least in the initial stage of molding, and the molding material 5 having the thermosetting synthetic resin injected into the gap as the main component is located on the lower mold part 2 side and the upper mold part 2. It is preferable that the curing speed be different on the mold portion 3 side. By adopting such a method, at the initial stage of molding of the molding material 5 containing the thermosetting synthetic resin as the main component, either the lower mold part 2 side or the upper mold part 3 side starts to rapidly cure and shrink. But,
Since the other side has fluidity, the molding material corresponding to the amount of contraction due to the injection pressure constantly applied at the time of molding through the portion having fluidity on the other side is It is newly injected and filled, and as a result, it is possible to manufacture a thermosetting synthetic resin molded product having uniform thickness due to shrinkage.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the embodiments shown in the accompanying drawings.

As shown in FIG. 1, the molding die 1 is composed of a lower mold part 2 and an upper mold part 3. When the lower mold part 2 and the upper mold part 3 are set, The gap 4 of the cavity formed between the upper mold part 3 and the upper mold part 3 is set to be the same as the thickness of the final molded product (the width of the gap 4 is different in each part of the final molded product. The width of the gap 4 is different in each part), and a sealing material 6 is interposed between the lower mold part 2 and the upper mold part 3 at the outer peripheral part of the cavity to prevent resin leakage. Lower mold part 2 on the outer periphery of the cavity
An injection part 7 is further provided between the upper mold part 3 and the upper mold part 3. In the present invention, the lower mold part 2 and the upper mold part 3 are set, and the gap 4 of the cavity formed between the lower mold part 2 and the upper mold part 3 is the same as the thickness of the final molded product. While maintaining the state set to, the subsequent injection of the molding material 5 containing the thermosetting synthetic resin as the main component and the subsequent molding are performed.

A molding material 5 containing a thermosetting synthetic resin as a main component
Is based on a thermosetting synthetic resin such as acrylic resin,
This was obtained by mixing it in a tank for compounding, mixing a pigment, a release agent, and a curing agent, stirring and defoaming it. For example, as an example, a thermosetting synthetic resin such as methylmethacrylic (I Asterite manufactured by CI Japan Co., Ltd.)
100 parts by weight, 0.4 part by weight of organic peroxide (Perkadox 16 manufactured by Kayaku Akzo Co., Ltd.) as a curing agent (a), organic peroxide (Laurox manufactured by Kayaku Akzo Co., Ltd.) as a curing agent (b) 0.2 parts by weight, 0.04 parts by weight of stearic acid as the release agent (a), and 0.04 parts by weight of Sunseparer (manufactured by Sanyo Kasei Co., Ltd.) as the release agent (b) are obtained. .

The molding material 5 containing the thermosetting synthetic resin as the main component obtained as described above is subdivided into the injection pressure tank 8 and the injection hose 9 provided in the injection pressure tank 8 is used as described above. It is connected to an injection part 7 communicating with the gap 4 provided in the molding die 1. Then, air pressure is applied to the injection pressure tank 8 so that the molding material 5 in the injection pressure tank 8 is injected from the injection part 7 into the gap 4 between the lower mold part 2 and the upper mold part 3 of the mold 1. Inject.
The injection pressure of the molding material 5 in this case is, for example, 1
Is about 1.5 kgf / cm ² . In this way, the molding material 5 is injected and filled into the gap 4 while maintaining the state where the width is set to be the same as the thickness of the final molded product, and the injection pressure is continued to be applied to the gap 4 even after the injection is completed. The thermosetting synthetic resin 5 is molded while being continuously injected.

Immediately after the injection of the molding material 5 into the gap 4 by the injection pressure of 1 to 1.5 kgf / cm ² , the pressure is increased by the injection pressure tank 8 to 4.5 to 4.5.
The molding is performed while continuously applying an injection pressure of 5 kgf / cm ² .

In the molding, the temperature of the molding die 1 is controlled such that the lower mold part 2 and the upper mold part 3 have a temperature difference at least at the initial stage of molding. As a result, the curing speed is made different between the lower mold part 2 side and the upper mold part 3 side of the thermosetting synthetic resin 5 injected into the gap 4. FIG. 2 shows a graph showing an example of temperature control of the molding die 1. FIG. 2A shows the lower mold 2.
2 (b) is a graph showing temperature management in the upper mold 3. FIG. In the embodiment shown in FIG. 2, the temperature of both the lower mold 2 and the upper mold 3 is 50 ° C. when the molding material 5 is injected into the gap 4. When the injection of the molding material 5 into the gap 4 is completed, the temperature of the lower mold 2 is raised to 80 ° C., and 1 minute later, to 95 ° C. On the other hand, the upper mold 3 is kept at 50 ° C. for a while after the completion of the injection, is heated to 80 ° C. 10 minutes later, and is further heated to 95 ° C. 5 minutes later (15 minutes in total after the injection). The temperature of the mold 1 is controlled.

Here, in the above-mentioned embodiment, the lower die second surface side is manufactured.
Since it is the product side, the lower mold 2 to show the product side cleanly
The temperature is raised first, but in the present invention,
In addition, the lower mold 2 side, which is the product surface side, is cured first and then stored.
The molding material 5 has fluidity on the upper mold 3 side at the stage when it starts to shrink.
Therefore, it is necessary to pressurize the gap 4 for injection during molding.
Due to the continuous injection pressure from tank 8,
Molding material 5 corresponding to the amount of curing shrinkage on the lower mold 2 side is new
Molded on the upper mold 3 side that has been injected under pressure and remains fluid
While pressing the material 5, the thickness of the final molded product up to every corner of the gap 4
Will be filled to be the same as. in this case,
Pressurization for injection even if the fluidity of the molding material 5 on the upper mold 3 side is reduced
The injection pressure by the tank 8 is 1 to 1.5 kg at the time of initial injection.
f / cm ²From 4.5 to 5 kgf / cm²Is raised to
In this way, it is certain that a new amount of new material equivalent to the shrinkage of the molding material 5
The shape material 5 can be replenished and injected.

As a result, the lower mold 2 and the upper mold 3 are not required to control the lower mold part 2 by the air bag in accordance with the curing shrinkage of the thermosetting synthetic resin as in the conventional case.
Set the gap 4 between and the same as the wall thickness of the final molded product,
Even if molding is performed without changing this, a thermosetting synthetic resin molded product having no unevenness in wall thickness due to shrinkage at the stage of the final molded product and therefore no unevenness can be manufactured.

Further, in the conventional art, since the rising portion of the molded product is not orthogonal to the direction in which the pressure is applied by the airbag, the pressure of the airbag is not sufficiently applied to the rising portion of the molded product. Molding defects such as unevenness were generated, and a correction step of reinforcing this molding defect part by FRF was necessary, but according to the present invention as described above, the molding material corresponding to the amount of curing shrinkage. Since it is replenished by pressure injection, the molding material
Since a new molding material 5 is replenished and injected in an amount corresponding to the amount of shrinkage, molding defects such as unevenness do not occur.
It does not require a post-correction step of reinforcement by RF.

Further, by continuously pressurizing the molding material 5 during molding and applying an internal pressure, the boiling point of the molding material 5 can be raised and the temperature of the molding die 1 can be raised quickly. Therefore, in the case where the internal pressure is not applied to the molding material 5 at the time of molding as in the conventional molding, molding can be performed under the curing condition which is impossible due to foaming (boiling phenomenon), and the curing time can be shortened. Is.

The amount of the molding material 5 prepared in the injection pressure tank 8 is preferably one molding amount. During the molding time (30 minutes), the injection pressure tank 8 remains in the vicinity of the mold 1, and the mold 1 is heated with warm water of 50 to 90 ° C. The temperature in the vicinity of the mold 1 becomes considerably high (especially in summer, the temperature rises further), which may cause gelation of the molding material 5 in the injection pressure tank 8. The amount of the molding material 5 to be prepared is for one molding.

[0021]

As described above, in the invention according to claim 1 of the present invention, the gap between the lower mold part and the upper mold part of the mold is set to be the same as the thickness of the final molded product. In this state, after injecting the thermosetting synthetic resin into the gap and after injecting into the gap,
Since the molding is performed while continuing to apply the injection pressure and continuously injecting the thermosetting synthetic resin, the molding material shrinks when molding the molding material containing the thermosetting synthetic resin as the main component. A new molding material is injected under pressure due to the contraction, which makes it possible to manufacture a thermosetting synthetic resin molded product that has no unevenness in the wall thickness due to shrinkage at the stage of the final molded product, and therefore has no irregularities. In addition, unlike the conventional case, a correction step of reinforce a defective molding portion by FRF is not required, and, in molding, the gap between the lower mold portion and the upper mold portion of the mold is finally molded. Since the subsequent molding is performed with the same setting as the thickness of the product and maintaining this setting, it is possible to cope with the curing shrinkage of the molding material mainly composed of thermosetting synthetic resin as in the past. Lower mold by back Molding it is not necessary to follow the are those that can be easily.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, a temperature difference is created between the lower mold part and the upper mold part at least at the initial stage of molding to form a gap. Since the curing speed is different between the lower mold part side and the upper mold part side of the injected thermosetting synthetic resin, at the initial stage of molding of the molding material containing the thermosetting synthetic resin as the main component, the lower mold part side or Although either one of the upper mold part side starts to rapidly cure and shrink, the other side has fluidity, so that the other side always has fluidity through the part having fluidity on the other side. A molding material corresponding to the amount of shrinkage due to the applied injection pressure will be newly injected and filled, and as a result, a thermosetting synthetic resin molded product with uniform thickness due to shrinkage can be manufactured by a simple method. It will be possible to manufacture.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a molding apparatus of the present invention.

FIG. 2 shows temperature control of a mold according to the present invention,
(A) is a graph showing temperature management of the lower mold, and (b) is a graph showing temperature management of the upper mold.

FIG. 3 is a schematic explanatory view of a conventional molding apparatus.

FIG. 4 is an explanatory diagram illustrating that the lower die is moved by the airbag of the conventional example to change the clearance of the gap;
(A) is explanatory drawing which shows the time of mold matching (before injection | pouring of molding material), (b) is explanatory drawing which shows the completion of injection | pouring of molding material, (c) is the completion time of hardening (before demolding). FIG.

[Explanation of symbols]

1 Mold 2 Lower mold part 3 Upper mold part 4 gap 5 Molding material

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI B29C 45/78 B29C 45/78 // B29K 101: 10 B29K 101: 10 (72) Inventor Ryoji Matsui Wakamatsu-ku, Kitakyushu, Fukuoka Prefecture 18 Yasuse No. 1 in Kitakyushu Matsushita Electric Works, Ltd. (56) References JP-A-60-21225 (JP, A) JP-A 2000-43110 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B29C 45/00-45/84 B29C 43/00-43/58

Claims (2)

(57) [Claims] 1. A thermosetting composition is set in the gap between the lower mold part and the upper mold part of the mold so that the gap is set to be the same as the thickness of the final molded product and the setting is maintained. Manufacture of thermosetting synthetic resin molded products characterized by injecting resin and molding while continuing to apply injection pressure after completion of injection into the gap and subsequently injecting molding material mainly composed of thermosetting synthetic resin Method. 2. A lower mold part side and an upper mold part side of a molding material having a thermosetting synthetic resin as a main component, which has a temperature difference between the lower mold part and the upper mold part at least in the initial stage of molding and is injected into the gap. The method for producing a thermosetting synthetic resin molded article according to claim 1, wherein the curing speed is changed by.