JPS59227412A - Preparation of molded synthetic resin article from fluidized polymerizable substance - Google Patents

Abstract

PURPOSE:To make it possible to repeatedly use a gasket and to obtain a molded article faithful to the surface state of a mold, by moving each heat exchanger by transmitting the thickness change based on the volumetric change of cell content to the same through a compression spring. CONSTITUTION:The volume of the content in each cell 6 changes according to the advance of polymerization reaction but pressing force generated by the reduction in the interval of heat exchangers 1 at both ends is transmitted by each compression spring 10 and each heat exchanger 1 small enough in moving resistance is easily moved by the pressing force of the compression spring 10 and intervals between the cells 6 are equally reduced. Because the reduced portion of the interval between the heat exchangers at both ends corresponds only to the sum total of the thickness reduced portion caused by the volumetric reduction of the content in each cell 6, a gap and pressing force are not generated at all between the content and the heat exchange surface 1a in each cell 6. Therefore, a molded article becomes faithful to the surface state of a mold, that is, the heat exchange surface 1a.

Description

DETAILED DESCRIPTION OF THE INVENTION In manufacturing a synthetic resin molded product by a casting method using a plurality of molds at the same time, the present invention provides a method for manufacturing a synthetic resin molded product by using a plurality of molds at the same time. A cell configured by sealing with a gasket is used as a formwork, and a pressing force that displaces each heat exchanger as the contents change to K is applied to the heat exchanger without passing through a gasket. The present invention relates to a method for producing synthetic 41111 & molded products from a fluid polymerizable material which is conveyed by a compressed spring, thus making it possible to repeatedly use the gasket and to obtain molded products with irregular surface contours.

Conventionally, synthetic resin moldings, especially synthetic resin plates, have been produced by the so-called casting method, in which a fluid polymerizable substance such as methyl methacrylate monomer or partially polymerized methyl methacrylate is polymerized in a mold. Various methods have been implemented or proposed. For example, one or more cells are constructed by sandwiching a compressible gasket between two flat plates such as glass plates, or by arranging the flat plates and compressible gaskets alternately, and the fluid is contained in the cell. After the polymerizable substance is injected, it is heated in a hot water bath, heat exchanger, or other appropriate means to polymerize.

In addition, a pressure-adjustable sealed chamber includes a cell with an open top formed by defining gaps between seven glass sheets with spacers and sealing with a compressible gasket, and a pressure equalizing pipe is provided between the sealed chamber and the sealed chamber. A method is also known in which heating medium circuits are placed alternately in contact with connected hollow metal plates, and polymerizable substances in the cells are polymerized under reduced temperature while defoaming under reduced pressure (Japanese Patent Publication No. 51-15833). issue). As compressible gaskets used in such conventional methods, gaskets made of synthetic resins such as soft vinyl chloride, silicone-based synthetic rubber, fluorine-based synthetic rubber, polyethylene, and polypropylene are generally used. However, with gaskets made of such materials, for example, in the case of soft vinyl chloride, the plasticizer in the gasket is extracted during polymerization by the polymerizable substance injected into the cell, and the gasket gradually becomes hard and loses its elasticity. Even if the gasket is made of other materials, the force compressing the gasket will exceed its elastic limit due to the temperature rise during polymerization, leaving permanent strain on the gasket, making it impossible to use it repeatedly, and the gasket will be damaged each time it is polymerized. There was a drawback that it was necessary to replace it. In addition, the volume of polymerizable substances, especially methyl methacrylate, changes as the polymerization progresses (
In this case, the material shrinks and irregularly creates voids between the cell wall and the surface of the mold, which does not conform to the surface condition of the mold, often resulting in defective molded products. Therefore, it is necessary to change the gap between the facing surfaces of the flat plates constituting the cell to follow the volume change that occurs as polymerization progresses, but the conventional method described above does not adopt effective means to deal with such volume changes. There were some drawbacks that were not addressed.

The present inventor has aimed to eliminate the drawbacks of the above-mentioned prior art, and to provide a method for manufacturing a synthetic resin molded product that allows the gasket to be used repeatedly and that also allows the molded product to conform to the surface condition of the mold. As a result of research, 1 between the faces that make up the cell! The present invention was constructed based on the fact that the object can be achieved by transmitting the pressing force that reduces lit' only by a compression spring without passing through a gasket.

That is, the present invention has six or more heat exchange bodies each having a temperature-controlled heat exchange surface on at least one side of 41ifi, which are arranged coaxially and facing each other with a gap so that the heat exchange surfaces are substantially vertical. When arranging the heat exchangers, the heat exchangers are arranged so as to be movable in the direction in which they are arranged, by sealing the remaining part with one side of a band-shaped gasket, excluding at least a part above the gap when arranging the heat exchangers to form two or more sets of cells; Compression springs that can generate a sufficiently large drag force against the movement resistance of each heat exchanger and have substantially the same spring elasticity coefficients are installed between each heat exchanger, and press the heat exchanger at the end. The gap between the opposing heat exchange surfaces that make up each cell is adjusted to a predetermined size, and then a fluid polymeric substance is injected into each cell, and the temperature of each cell is fully controlled by the heat exchanger. A suppressing force that changes the distance between the heat exchangers at both ends by the sum of changes in thickness due to changes in the volume of the contents of each cell that occur as polymerization progresses within the cell is transmitted to each heat exchanger via the compression spring. The present invention relates to a method for producing a synthetic resin molded article from a fluid polymerizable material, characterized in that the size of the gap in each cell is uniformly changed by moving the cell.

Hereinafter, the method of the present invention will be explained in detail with reference to the drawings.

Fig. 1 is a cross-sectional explanatory diagram showing an example of a state in which compression springs are installed and arranged between each heat exchanger, and Fig. 2 is an A-A in Fig. 1.
Line end view, Fig. 6 A) and (W) are explanatory diagrams showing examples of sealing parts by gaskets, Fig. 4 is a cross-sectional explanatory diagram showing another example corresponding to Fig. A cross-sectional explanatory view showing a main part of an example of the attachment part, Fig. 6 is an overall explanatory view showing a simplified example of a state in which polymerization proceeds while reducing the distance between the heat exchangers at both ends, and Fig. 7 shows a state in which polymerization is progressed. FIG. 2 is an enlarged explanatory diagram of piping around a heat exchanger at a time.

In the method of the present invention, a cell is constructed and used as a mold for molding the warp as described below. That is, first, as shown in FIGS. 1 and 4, six or more heat exchange bodies 1 each having a heat exchange surface 1a whose temperature is controlled on at least one side are prepared. As shown in FIG. 1, this heat exchanger 1 has two cases in which a flat plate 6 such as a glass plate or a metal plate is closely attached to one or both sides of the heat exchanger and the surface of the flat plate A is used as the heat exchange surface 1a. As shown in FIG. 4, there is a case where the heat exchanger itself is used as the heat exchange body 1, and one or both sides of the heat exchanger is used as the heat exchange surface 1a. In the former case, the flat plate A may be attached to the heat exchanger 2 by any appropriate method, but in the example of FIG. 1, as shown in FIG. It is engaged. In the drawing, the inside of the heat exchanger is drawn as a cavity, but
Various known structures can be used. Six or more such heat exchange bodies 1 are arranged horizontally on the same axis so that the heat exchange surfaces 1a are substantially vertical.
When cells a are placed facing each other in sequence with a gap provided, two or more sets of cells 6 are formed by removing a part above the gap and sealing the remaining part with one side of a band-shaped gasket 5. As for when to seal the gap in the heat exchange surface 1a with the gasket 5, for example, if the heat exchanger itself is used as the heat exchanger 1, it should be sealed after the heat exchanger 1 is placed, or as shown in FIG. As will be described later, a gasket 5 is attached to the heat exchanger 1 on one side in advance, and the heat exchanger 2 is connected to the heat exchanger 2 as the heat exchanger 1 as shown in FIG. When using flat plates 6t, in addition to sealing them using the same procedure as above, seal the gaps with gaskets 5 before attaching the two flat plates 6t to the heat exchangers 2 on both sides, and then The flat plates 6 can also be attached to the heat exchangers arranged horizontally at predetermined positions as described above by engaging with each other. As described above, the timing at which the heat exchange surface 1a is sealed by the gasket 5 can vary depending on the method of attaching the gasket 5, which will be described later.

The part to be sealed by the gasket 5 is a part (a) above the gap between the opposing heat exchange surfaces 1a as shown in Fig. 6 or the entire part (excluding the cutout); An opening 6a of cell B is formed above.

Sealing by the band-shaped gasket 5 is achieved by bringing one side of the gasket 5 on the same side into close contact with each of the opposing heat exchange surfaces 1a forming a gap.

Therefore, several methods of attachment are shown below. The gasket 5 shown in FIG. 1 is installed by bending the gasket 5t into a U-shaped cross section along the length direction and inserting it around the gap excluding the opening 6a, and then facing the inner surface for heat exchange. This method uses a method in which both side edges of the gasket 5 are fixed to, for example, the engagement frame 4 with screws or an adhesive to seal the gasket 5 in close contact with each of the surfaces 1a.

As described above, such sealing is performed on the remaining part except for the upper part of the gap, and the side part is in the state shown in FIG. 2. In addition, the gasket 5 shown in FIG. 4 is attached using the method shown in FIG.
Only one edge of U is fixed to the extended surface of the heat exchange surface 1a, and
This is a method of sealing by filling the inside of the letter shape with elastic sponge 7 and bringing the other edge into pressure contact with the extended surface of the heat exchange surface 1a on the opposite side. Furthermore,
The installation of the gasket 5 shown in FIG. 5 is a modification of the case shown in FIG. The heat exchange surface 1a is sealed by sandwiching the heat exchange surface 1a between the heat exchange surfaces 1a and 1a.

When arranging six or more heat exchangers 1 horizontally to form cells 6 by sealing the gaps between the opposing heat exchange surfaces 1a with gaskets 5, each heat exchanger 1 is arranged in the direction of arrangement. For example, it can be arranged movably by the following method.

The method shown in FIG. 1 is based on the method shown in FIG.
A sliding hole is bored in the heat exchanger 1, a fixed shaft 8 is provided in a predetermined direction, and the sliding hole of each heat exchanger 1 is inserted into the fixed shaft 8 so that the heat exchanger 1 is movably suspended. The method shown in FIG. 4 is a method in which a linear moving tool 9 with a slide pairing having low movement resistance is movably mounted on the lower surface of the heat exchanger sandwich 1.

On the other hand, a compression spring 10 is installed between each heat exchanger 10. This compression spring 10 is capable of generating a sufficiently large resistance against the movement resistance of each heat exchanger 1, and has the same spring elastic coefficient. It is most preferable that the spring elastic modulus of each compression spring 10 is equal to each other in this way, but since it is difficult to manufacture such a compression spring 10, the heat exchanger 1 is placed in a substantially vertical state as described later. They may have substantially the same elastic modulus as long as they can be held and moved. The movement resistance of the heat exchanger 1 is the sliding resistance between the sliding hole of the upper flange 1b and the fixed shaft 8 in the above example, and the rolling resistance of the bearing of the linear moving tool 9. Therefore, these movement resistances can be reduced. The smaller the elastic modulus of the compression spring 10 becomes, the smaller the compression spring 10 becomes.

In this way, the heat exchanger 1 receives a pressing force from the compression spring 10 that is sufficiently greater than its movement resistance, and can be easily moved. As the compression spring 10, in addition to the coil spring shown in the figure, bamboo springs, disc springs, etc. can also be used.

It is preferable to install a plurality of compression springs 10 per gap in the heat exchanger 1 in order to evenly transmit the pressing force described later.
For example, in FIG. 1, between the upper flange 1b of the heat exchanger 1 and the lower flange 1
0, and in FIG. 4, they are installed at the upper and lower parts of the heat exchanger 1, respectively, and more preferably 4 or 8 at approximately equal intervals over the entire periphery of the heat exchanger 1. Attach multiple items such as The compression spring 10 may be attached before or after the gasket 5 is attached, depending on the method of attaching the gasket 5.

In this way, six or more heat exchangers 1 are arranged so as to be movable in the line direction, each gap is sealed with a gasket 5 to form a cell 6, and a compression spring 1 is inserted between each heat exchanger 1.
U is attached, for example in FIG.

It is constructed as shown in FIG. From this state, a fluid polymerizable substance is combined as follows.

For example, as shown in FIG. 6, the heat exchanger 1 and the like are configured between the pressurizing devices 11 as shown in FIG. ) to the specified size. This adjustment can be performed, for example, by operating the piston rod 11a of the pressurizing device 11 to adjust the distance between both ends. Once the gap between the heat exchange surfaces 1a and 1a has been adjusted, a predetermined amount or Wr is injected into each cell from the opening 6a using the injection pipe 12 around the heat exchanger shown in FIG. L Shihe/l
/ Infuse with reeds. Then, the temperature-controlled heat medium is introduced into each heat exchanger 1 from the heat medium inlet pipe 16 and the heat medium outlet pipe 14
The temperature of the contents of cell B is adjusted by sending it out through the valley heat exchange surface 1a. Normally, the heat exchange surface 1a is placed in a state where the polymerizable substance is heated by a heating medium at the start of polymerization. The system is kept in a state where heat is removed from the system, and just before the end of the polymerization reaction, the temperature of the heating medium is increased again to complete the polymerization reaction. The temperature conditions at the time of fastening may be appropriately set depending on the type of composite material used.

In this way, as the polymerization reaction progresses, the volume of the contents of cell B generally changes, but in the method of the present invention, as explained below, the volume of the contents of each cell B is changed. The spacing between the heat exchangers 1 at both ends is changed by the sum of the thickness changes due to By holding the cells in the same state and moving them, the gaps between the cells B can be uniformly reduced. Hereinafter, a case where the volume of the contents of cell B shrinks will be explained as an example. For example, considering the arrangement of the heat exchangers 1 as shown in FIG. 6, the heat exchangers 1 at both ends are
This will reduce the distance between the two. Specifically, pressurizing device 1
The moving speed of the 11 piston rods 11a is programmed and controlled according to the change over time of the total thickness reduction of the contents of each cell 6. In FIG. 6, the array of heat exchangers 1 is sandwiched between the pressure devices 11 on both sides, but in order to reduce the distance between the heat exchangers 1 at both ends, it is not necessary to move the piston rods 11a of the pressure devices 11 on both sides. It is not necessary, and one piston rod 11a may be stopped while the other is moved; in this case, the stopped piston rod 1
A fixed wall or the like may be used instead of 1a. In this way, the distance between the heat exchangers 1 at both ends is reduced by the movement of the piston rod 11a. Compression spring 10 is heat exchanger 1
A sufficiently large drag force can be generated against the movement resistance of the upper flange portion 1b, and the spring elastic modulus of each compression spring 10 is substantially equal to each other. Therefore, the pressing force caused by the reduction in the distance between the heat exchangers 1 at both ends is transmitted by each compression spring 10, and the plurality of compression springs 10
tend to contract all at once and uniformly, as if they were a single compression spring with a uniform elastic modulus. As a result, each heat exchanger 1 having a sufficiently small movement resistance can be easily moved by the pressing force of the compression spring 10, and the gap between each cell B can be uniformly reduced. The length of the interval between the heat exchangers 1 at both ends is the sum of the constant thickness of each heat exchanger 1 and the variable sum of the gaps between the cells. Therefore, reducing the gap between the heat exchangers 1 at both ends as described above reduces only the variable gap between each cell 6, and this reduction is equal to the total thickness reduction due to volumetric contraction of the contents of each cell A. In each cell, the contents and heat exchange surface 1
There is no gap or pressing force between the material and the material a. Therefore, the molded product conforms to the surface condition of the mold, that is, the heat exchange surface 1a. Well, the gasket 5 is not subjected to any load when the heat exchanger 1 moves, so its deformation and deterioration are that much less, and the gasket 50 only needs to seal the gap between the heat exchange surfaces 1a, so it is somewhat There is no problem with deformation or alteration as long as it does not affect the sealing action, and therefore it can be used repeatedly. The above explanation deals with the case where the volume of the contents of the cell 6 shrinks, but even when the volume increases, the gap between the heat exchangers 10 at both ends is expanded by the total thickness increase, and the compression spring 10 generated thereby The pressing force caused by this moves each heat exchanger 1 through each compression spring 1U, and uniformly expands the gap between each cell B, thereby acting in the same manner as in the case of contraction.

As described above, the polymerization reaction approaches completion, and the volume of the contents of cell A no longer changes, and the heat exchangers 10 at both ends
When changing the interval is stopped and polymerization is completed, the gasket 5 is removed as necessary, the heat exchangers 1 are separated from each other, and the molded product is taken out. Then repeat the above steps using the same gasket.

As described above, according to the method of the present invention, a compression spring is installed between each heat exchanger, and the space between each heat exchanger surface is sealed with vJi,'t gasket surface to form a cell, thereby controlling the progress of polymerization. By changing the distance between the heat exchangers at both ends to follow the volume change of the contents of the cell, the resulting pressing force is transmitted to each heat exchanger through a plurality of compression springs, and each Compression springs generate a sufficiently large drag force against the movement resistance of each heat exchanger, and have approximately the same spring elasticity coefficients, so multiple compression springs can act simultaneously as if they were a single compression spring. It contracts or expands uniformly, and as a result, the change in the gap between the heat exchangers at both ends causes the gap in each cell to change equally by the change in thickness due to the change in volume of the contents, so in each cell, the content and heat are There are no gaps or pressure between the exchange surface and the mold, so the molded product remains exactly as it is on the surface of the mold. Since the gasket only needs to perform a sealing function, it can be used repeatedly. The present invention H having such excellent effects
This will greatly contribute to improving the quality of synthetic resin molded products using the casting method and facilitating their manufacture.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional explanatory diagram showing an example of a state where compression springs are installed and arranged between each heat exchanger, Fig. 2 11-1: End view taken along line A-A in Fig. 1, Fig. 6 1 - () and (b) are explanatory diagrams showing examples of sealing parts by gaskets, respectively.
The figure is a cross-sectional explanatory diagram showing another example corresponding to Figure 1, Figure 5 is a cross-sectional explanatory diagram showing the main part of an example of the gasket mounting part, and Figure 6 is a cross-sectional explanatory diagram showing the main part of an example of the gasket mounting part. Fig. 7 is an overall explanatory diagram showing a simplified example of a state in which polymerization is allowed to proceed, and Fig. 7 is an enlarged explanatory diagram of piping around a heat exchanger during polymerization. 1. Heat exchange body 1a. Heat exchange surface 1b. Upper flange 1c. Lower flange 2. Heat exchanger 6. Flat plate 4. Engagement frame 5. Gasket 6. Excellent cell 6a. - Opening 7 - Elastic sponge 8 - Fixed shaft 9 - Linear moving tool 10 - Compression spring 11 - Pressure device 11a - Piston rod 12 - Injection pipe 16 - Heat medium inlet pipe 14 - Heat medium outlet pipe 11 Figure 2 Figure 3 (A)
(b) Figure 4

Claims (1)

[Claims] 1 This applies when six or more heat exchangers each having a temperature-controlled heat exchange surface on at least one side are arranged coaxially and facing each other with a gap so that the heat exchange surfaces are substantially vertical. At least a part above the gap is removed and the remaining part is sealed with one side of a band-shaped gasket to form two or more sets of cells, and each heat exchanger is arranged so as to be movable in the direction in which each heat exchanger is arranged. A compression spring capable of generating a sufficiently large drag force against the movement resistance of f: Adjust the gap between the opposing heat exchange surfaces to a predetermined size of a1m, then inject a fluid polymeric substance into each cell and adjust the temperature of each cell using a heat exchanger. A pressing force is transmitted to each heat exchanger through the compression spring to change the distance between the heat exchangers at both ends by the sum of thickness changes due to volume changes of the contents of each cell as the polymerization progresses within the cell. 1. A method for producing a synthetic resin molded article from a fluid polymerizable material, characterized in that the size of the gap in each cell is uniformly changed by moving each cell.