JPH0235651B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding foamed resin and a molding jig used for the molding, and in particular, when molding a cylindrical foamed resin used for a heat insulating cover of a pipe, etc. By using lightweight plate materials for the inner and outer plates of the mold, it is easier to disassemble and reassemble the mold, speeding up molding, improving the quality of the molded product, and reducing the cost of the mold. The present invention relates to a method of molding a foamed resin with a reduced amount of foam and a molding jig that is extremely conveniently used in the molding method.

Due to the effects of the recent oil crises and for the purpose of controlling pollution, liquefied natural gas and liquefied petroleum gas have been widely used as fuel for power generation and city gas. As is well known, since these liquefied gases are stored or transported at low temperatures, their storage tanks, piping, etc. must be insulated. These storage tanks, piping, etc. have recently become larger and larger. Taking piping as an example, the size ranges from 20B to 40B, and the insulation thickness needs to be 150 to 250 mm. FIG. 1 (a) is a sectional view, and (b) is a front view) is a diagram showing an example of such a piping insulation method. In the figure, a heat insulating cover 2 is attached to the outside of the pipe 1. The heat insulating cover 2 has the shape of a cylinder divided in half, and is molded to a predetermined length for ease of handling. Meji 3 is filled between the piping 1 and the heat insulating cover 2 and between the heat insulating covers 2 and fixed to each other. When the diameter of the pipe is large and the insulation thickness is large, a heat insulation cover in the form of a cylinder divided into three or four parts may be used.

Foamed urethane resin is often used as the material for this heat insulating cover. This is because, in addition to its extremely excellent insulation performance, it can be easily foamed on-site, which has the advantage of significantly reducing transportation costs.

Conventionally, this foamed urethane resin insulation cover was the second
It was molded using a mold as shown in the figure (perspective view). That is, in the same figure, the mold 11
It consists of a female mold 12, a male mold 13, and two end plates 14. A half-cylindrical space 12A having a diameter approximately equal to the outer diameter of the required heat insulating cover is provided in the center of the female mold 12, and a half cylindrical space 12A having a diameter approximately equal to the outer diameter of the required heat insulating cover is provided in the center of the male mold 13. The length of the space 12A in which the cylindrical half-shaped protrusion 13A is provided and the length of the protrusion 13A are both made to substantially match the length of the required heat insulating cover. The end plate 14 is a plate having a height and width approximately equal to the height and width of the female mold 12.

When molding a heat insulating cover using this mold 11, the following procedure is performed.

Two end plates 14 are attached to the female mold 12.

Set the male mold 13 onto the female mold 12.

The female mold 12 and the male mold 13 are tightened using a tightening tool (not shown in FIG. 2).

Mix and stir the foamed urethane resin stock solution.

A foamed urethane resin stock solution is poured into the space 12A of the female mold 12.

After foaming and a predetermined curing period after foaming, the mold is disassembled in the reverse order to take out the heat insulating cover 2 (shown on the recess 12A of the female mold 12 in FIG. 2).

The conventional method of forming a heat insulating cover described above did not have any major drawbacks as long as the size of the heat insulating cover was small, but as the size of the heat insulating cover gradually increases, the following drawbacks appear. It became.

When foaming urethane resin, foaming pressure is applied to each part of the mold, which tends to cause deformation of the mold. To prevent this, the mold must be thick and highly rigid, making the mold expensive.

Since each component of the mold is heavy, it takes a lot of time to disassemble and assemble it, and a large crane and the like are required, which increases the equipment cost and ultimately increases the cost of the heat insulating cover.

The heat insulating cover is formed in the shape of a cylindrical half, but the density tends to be high near the half face, which increases the thermal conductivity of that part and deteriorates the heat insulation performance.

As described above, since the density of each part of the molded product varies, the molded product may be deformed after molding.

Deformation of the molded product can be prevented by leaving it in the mold for a long time, but this will make the mold rotate poorly, requiring many molds, and ultimately increasing the cost of the heat insulating cover. .

It is desirable to preheat or heat the mold to 40° to 50°C to promote foaming, but as each component is thick as described above, it has a large heat capacity and takes time to heat. Also, there is a lot of wasted heating energy.

The present invention eliminates the drawbacks of the conventional foam resin molding methods described above, provides a method for molding foam resin that is easy to mold, has excellent product performance, and has low cost, and at the same time, The purpose of this invention is to provide a molding jig that can be used extremely conveniently.

The present invention consists of a mold consisting of two groove-shaped rings, an inner plate made of a thin plate, an outer plate, etc., and has a tightening band from the outside and a tension rod from the inside to prevent strain caused by foaming pressure. The first of the above objects is achieved by supporting the molding jig, and the second of the above objects is achieved by constructing the forming jig from a center shaft and a tension rod that fits therein. have achieved something.

Embodiments of the present invention will be described below based on the drawings. FIG. 3 shows a mold for molding foamed resin according to the present invention, with A being a plan view and B being a sectional view. In the figure, the mold 21 is composed of an upper groove ring 22, a lower groove ring 23, an outer plate 24, an inner plate 25, a pair of plate pieces 26 with bolts and nuts, a tightening band 27, a molding jig 31, etc. It's on. The upper groove ring 22 is shown in Figure 4 (A is a plan view and B is a sectional view).
As shown in , it is a ring with a groove-shaped cross section, and its outer diameter is approximately equal to the outer diameter of the required heat insulating cover, and its inner diameter is approximately equal to the inner diameter of the required heat insulating cover. The upper channel ring 22 is provided with a hole 22A for resin injection. Lower groove ring 2
3 has the same shape as the upper channel ring, but does not have a hole for resin injection.

The two grooved rings 22, 23 are placed with their bottom faces facing each other and at a distance approximately equal to the length of the heat insulating cover, and an outer plate 24 is wrapped around the outside thereof. The outer plate 24 is made of a thin plate of metal or the like, and is bent in advance into a cylindrical shape having an inner diameter approximately equal to the outer diameter of the grooved rings 22 and 23. They are starting to overlap. As shown in an enlarged view in FIG. 5, if the overlapping portions are processed so that the thickness gradually decreases toward the edges, the molded product will be finished neatly without any steps on the outside. After the outer plate 24 has been wrapped and attached to both channel rings, a suitable number of tightening bands 27 are placed on its outer side. The tightening band 27 is made by bending a strip-shaped plate of metal or the like so that its inner diameter is approximately equal to the outer diameter of the outer plate 24, as shown in FIG. 6 (A is a plan view and B is a front view). It has a shape with both ends bent outward. A hole is drilled at both ends of this, and the bolt 2
7A is inserted, and a nut 27B is threaded onto the bolt 27A. By tightening the nut 27B, the inner diameter of the tightening band 27 becomes smaller and the outer plate 24 is tightened.

An inner plate 25 is inserted inside the two groove-shaped rings 22 and 23. The inner plate 25 is made of a thin plate of metal or the like, and is bent in advance into a cylindrical shape with an outer diameter approximately equal to the inner diameter of the grooved rings 22 and 23, and when rolled to the outer diameter, the end portion is a predetermined size. They are starting to overlap. This overlapping part is located on the outer plate 2 as shown in the enlarged view in Fig. 7A.
Similar to 4, it is desirable to process the wall so that the thickness gradually decreases toward the end. As shown in the figure, a pair of plate pieces 26 are provided inside the end of the inner plate 25.
is installed. A hole is bored in the upper and lower ends of this pair of plate pieces 26, and a bolt 26 is inserted into the hole.
A is inserted, and two nuts 26B are screwed into each bolt 26A. (In FIG. 3B, bolts and nuts are omitted and shown simply by dashed lines.) The bolt 26A is fixed to one of the plate pieces 26, and the nut 26B is attached to the bolt 26A so as to sandwich the other plate piece 26. They are screwed together. If you loosen the inner nut and tighten the outer nut in the state shown in Fig. 7A, the distance between both plate pieces 26 will become smaller and the
The state shown in Figure B is reached. To insert the inner plate 25 into the grooved rings 22, 23, carry out the state shown in FIG.
After it is assembled and molded, it is returned to the state shown in FIG. 7B and removed.

FIG. 8 is a diagram showing an example of the molding jig 31,
A is a plan view, B is a front view, and C is an enlarged sectional view of a main part. In the same figure, a molding jig 31 is composed of a center shaft 32 and a plurality of tension rods 33, etc., and the tension rods 33 are rotatably fitted to the center shaft 32 on a plane including its axis. ing. In the illustrated example, the center shaft 32 has a pin 3.
4 is fixed in a direction perpendicular to its axis, the tension rod 33 is provided with a boss 33A at its center, and a hole 33B is bored in the boss 33A. Further, a pin 34 is fitted into the hole 33B so as to be rotatable with respect to the other. The portion of the center shaft 32 through which the tension rod 33 passes is an elongated hole 32A that is long in the axial direction. The length of the tension rod 33 is the length of the inner plate 25 when the inner plate 25 is inserted and wound inside the two groove-shaped rings 22 and 23 and the outer diameter thereof becomes equal to the inner diameter of the groove-shaped rings. It is slightly larger than the inner diameter of. This molding jig 31 is inserted into the inside of the inner plate 25 with all of its tension rods 33 tilted (indicated by the two-dot chain line in FIG. The inner plate 25 is stretched by the inner plate 25, the inner plate 25 and the molding jig 31 are integrally fixed, and the foaming pressure applied to the inner plate 25 during foaming is supported.

FIG. 9 (A is a plan view and B is a front view) shows another example of the molding jig 31. In the figure, the center shaft 35 of the forming jig 31 has a prismatic shape in this example, and its cross section is a polygon (hexagonal in the illustrated case) having multiple pairs of mutually parallel opposite sides. . Further, there is a boss 36A in the center of the tension rod 36, and a through hole 36B with an elongated cross section is provided in the boss 36A, and the center shaft 35 is fitted into this through hole 36B. ,
The tension rod 36 is rotatable on a plane containing the axis of the center shaft 35. The length of the tension rod 36, the method of inserting it into the inner plate 25, and the method of tensioning are the same as in the above-described example.

Molding a foamed resin using the mold 21 described above is carried out by the following procedure.

(a) Place the groove ring 22 on top and the groove ring 23 on the bottom, wrap the outer plate 24 and inner plate 25,
The outer edges or inner edges of the grooved rings 22, 23 and the outer plate 24 or inner plate 25 are fixed using a vise or the like. When winding the inner plate 25, it goes without saying that if the bolts and nuts 26A, 26B attached to the plate piece 26 are used as described above, insertion and winding are easy.

(b) Tighten the outside of the outer plate 24 with the tightening band 27, and then attach the molding jig 31 to the inside of the inner plate 25.
Insert the tension rod 33 or 3 of the molding jig 31.
6 is held almost horizontally to support the inner plate 24. (It is also possible to assemble the mold horizontally for all or part of the above process, and then assemble it vertically.) (c) Inject the foamed resin liquid from the resin injection port 22A of the upper groove ring 22. . Depending on the foamed resin used, it may be desirable to preheat the mold before injection or heat it after injection. For foamed urethane resin, this preheating or heating temperature is 40°~
It is said that 50℃ is the best temperature, but hot air is usually used for heating.

(d) After the specified foaming and curing time has elapsed, the mold is disassembled and the molded product is removed. When disassembling the inner plate 25, the bolts attached to the plate piece 26,
The use of nuts 26A and 26B is as described above. (If the molded product is a heat insulating cover, cut the molded product into two with a saw or
~ Process into quarters. ) The above method for molding a foamed resin according to the present invention mainly describes foamed urethane resin.
It is obvious that the present invention can be effectively practiced with other foamed resins.

According to the method for molding foamed resin according to the present invention, since all the constituent parts of the mold are lightweight, handling is extremely easy, the time required for disassembling and reassembling the mold is extremely short, and the mold is also inexpensive. Since the foaming pressure applied to the mold during foaming of the resin is supported by a tightening band on the outer surface and a molding jig on the inner surface, the amount of deformation of the mold is minimal and the dimensional accuracy of the molded product is also good. Furthermore, since each part is lightweight, there is no need for a large crane or the like, which ultimately reduces the cost of the molded product.

Furthermore, since there are no irregularly shaped parts such as halved surfaces during molding, each part can be molded with extremely uniform density, improving the quality of the molded product. Furthermore, since there is no non-uniform density, there is little deformation after molding, the curing time during molding can be shortened, and the rotation rate of the mold can be greatly increased.
Furthermore, some resins require preheating or heating during molding, but each part of the mold is thin, so the heat capacity is small and the heating time is short.
Also, there is no wastage of energy.

The foamed resin molding jig according to the present invention also provides an extremely simple and effective means for preventing deformation of the inner plate for the above-described molding method, and is indispensable when performing the above-mentioned molding method. It can be said that it is an invention.

In summary, the present invention makes it possible to provide foamed resin molded products such as heat insulating covers at an extremely low cost with excellent quality, and in turn greatly contributes to the stable supply of energy in Japan, which is undergoing an oil crisis.

[Brief explanation of drawings]

Figure 1 shows an example of a piping insulation system, where A is a cross-sectional view, B is a front view, and Figure 2 shows a conventional mold used to mold a heat-insulating cover made of urethane foam resin. Fig. 3 is a perspective view showing a mold for foamed resin according to the present invention; Fig. 3 is a plan view;
B is a sectional view, FIG. 4 is a diagram showing the upper groove ring, A is a plan view, B is a sectional view, FIG. 5 is an enlarged view of the weight part of the outer plate, and FIG. 6 is a tightening band. In the figure, A is a plan view, B is a front view, FIGS. 7A and 7B are enlarged views of the weight part of the inner plate, and FIG. 8 is a diagram showing an example of a molding jig, and A is a plan view. , B is a front view, C is an enlarged sectional view of the main part, FIG. 9 is a diagram showing another example of the molding jig, A is a plan view, and B is a front view. 1...Piping, 2...Insulation cover, 3...Meji,
11... Molding mold, 12... Female mold, 13... Male mold, 14... End plate, 21... Molding die, 22... Upper groove ring, 22A... Resin injection hole, 23...
...Lower channel ring, 24...Outer plate, 25...Inner plate, 26...Plate piece, 26A...Bolt, 26B
... Nut, 27 ... Tightening band, 27A ... Bolt, 27B ... Nut, 31 ... Molding jig,
32...Center shaft, 33...Tension rod, 34
...Pin, 35...Center shaft, 36...Tension rod.

Claims (1)

[Claims] 1. A groove-shaped ring, another groove-shaped ring having the same shape as the one groove-shaped ring and provided with a hole for resin injection, and a thin plate formed into a substantially cylindrical shape. When the inner diameter is the same as the outer diameter of the groove ring, an outer plate having a shape such that the end portions thereof overlap by a predetermined dimension, and a thin plate formed into a substantially cylindrical shape, An inner plate having a shape such that its ends overlap by a predetermined dimension when the outer diameter is the same as the inner diameter of the ring, a pair of plate pieces fixed inside both ends of the inner plate, and the plate. A bolt inserted into a hole drilled in the piece, a nut screwed onto the bolt, and a plate piece formed into a cylindrical shape with an inner diameter slightly larger than the outer diameter of the groove ring, the end of which is formed into a cylindrical shape. a tightening band having bolts and nuts bent outward and attached to holes drilled at the ends; When the outer diameter of the plate is made the same as the inner diameter of the groove ring, a molding die consisting of a tension rod having a length slightly larger than the inner diameter of the inner plate and a forming jig is used, and the following is carried out. A method for molding a foamed resin according to the process steps (a) to (d). (a) Place the first groove ring at the bottom and the other groove ring at the top, wrap the outer plate on the outside and the inner plate on the inside, and then wrap the two groove rings, the outer plate, and the inner plate together. Assemble a hollow cylindrical mold by fixing it with a fixing device such as force (b) Tighten the outside of the mold with the tightening band, and support the inside with the molding jig (c) Foamed resin Inject the liquid through the resin injection hole in the other groove-shaped ring (d) After the specified foaming and curing time has elapsed, the mold is disassembled and the molded product is taken out, but when the inner plate is disassembled, it is fixed to the inner plate. 2. The foaming according to claim 1, wherein the foaming resin liquid is a foaming urethane resin liquid. How to mold resin. 3 Consists of a center shaft and a tension rod that is rotatably fitted to the center shaft on a plane including its axis, and the length of the tension rod is slightly longer than the inner diameter of the inner plate of the foam resin mold. A jig for foam resin molding that is characterized by its large dimensions. 4. The center shaft has a cylindrical shape, and a pin perpendicular to the axis thereof is fixed to the center shaft,
In the pin fixing part of the center shaft, a cylindrical side surface in a direction perpendicular to the pin has a through hole parallel to the axis of the center shaft, and the tension rod is rotatable around the pin in the center thereof. A jig for molding foamed resin according to claim 3, characterized in that the jig has a fitting hole. 5. The center shaft has a polygonal cross section having a plurality of pairs of mutually parallel opposing sides, and the tension rod has an elongated through hole in its center that fits on the outside of the center shaft. A jig for molding foamed resin according to claim 3, characterized in that: