JPH0235664B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a rectangular parallelepiped-like foam having a closed cell structure with wrinkles on the cell walls, and when stretched in three orthogonal axes (X, Y, and Z axes),
The axis has an elongation at break of 8 to 60%, and its Y
The present invention relates to a synthetic resin foam characterized by having an axial water vapor permeability of 1.5 [g/m ² hr°C] or less and high elongation properties in two specific directions. In recent years, there have been many attempts to utilize the properties (eg, heat insulation, compressive strength, etc.) of closed-cell foams by fixing them on the outer surface, inner surface, or inside of structures. In particular, this trend is remarkable today, when resource conservation and energy conservation have become national issues, and on the other hand, there are also phenomena where problems that were previously latent but not given attention to are now coming to the surface. For example, closed-cell rigid foam board has rigidity such as compressive strength, light weight, and heat insulation performance.
Foam boards have been used as insulation materials for buildings since early times, but when the surface to be fixed is the roof of a building with a curved surface, the outside surface of a tank, the inside surface of a tunnel, or the outside surface of a pipe, the rigidity of foam board, The elasticity becomes a problem, and it is difficult to tightly fix the foam board, and if you force the foam board to do so, the foam board will break or crack, so avoid deteriorating the insulation performance. There are drawbacks that make it difficult. However, cutting the surface of a foam board to fit a curved surface is not only technically difficult but also economically disadvantageous. This difficulty becomes more significant as the radius of curvature of the target surface becomes smaller and as the curvature becomes more complex. In addition, as a method to avoid this, a method has long been used in which a foam molded product that matches the curvature of the target surface is created in a factory and then transported to the site for use, but it is not compatible and is difficult to transport and store. , it is accompanied by significant difficulties in changing specifications. The present invention was made in view of the current situation, and an object thereof is to provide a foam that satisfies the following conditions 1 to 6. 1 Transport it as a flat plate and press it onto a cylindrical or spherical body to be insulated at the site. Alternatively, it should be possible to use it by pressing and bending it according to a mold with the required curvature, heating it, and shaping it according to the mold. 2. It does not require a large deforming force during the above-mentioned press construction and press processing, and has excellent so-called bending workability, which does not cause cracking, breakage, tearing, etc. during bending deformation. 3. Even after bending, it has sufficient compressive strength, has high insulation properties, and maintains its performance for a long period of time. 4 When used for cryogenic insulation applications such as storage and transportation of liquefied natural gas, etc., it can be used as a piping insulation cover, spherical tank insulation material, and panel material for square tanks.
It must have cryogenic properties in the axial direction, sufficient crack resistance, and durable heat insulation performance. 5. Even without the use of reinforcing composite materials, the panel must have cryogenic crack resistance, excellent heat insulation and mechanical properties, and creep resistance that can withstand high loads over long periods of time. 6. A rigid foam that has all of the properties listed in 1 to 5 above at a high level has an economical efficiency comparable to that of conventional foams. According to the present invention, all of the above objects of the present invention are achieved by providing a rectangular parallelepiped-like foam having a closed cell structure with wrinkles on the cell walls, and moving the cells along three axes (X, Y, Z) perpendicular to each other. Each average cell diameter (x, y, z) [mm] measured in the direction is the foam density (D) [Kg/m ³ ]
(approximately 20 to 100), 0.05y1.0 [mm],
In the range of y/x1.05, y/z1.05,
(-75log y+55)D(-5log y+20), water vapor permeability Py in the Y-axis direction [g/m ² hr]
satisfies a value of 1.5 or less, and furthermore, this foam is
When stretched in the Y and Z axis directions, the elongation at break in each direction is 60Ex between Ex, Ey, and Ez [%].
8, (8Ex−56)Ez in the range of 60Ez8
(1/8Ex+7) and (90-Ex)Ez However, a synthetic resin foam characterized by having an elongation characteristic of the relationship 8.3>Ex/Ey>1.8, 8.3>Ez/Ey>1.8 and Ex+Ez<12Ey. Therefore, it can be easily achieved. The contents of the present invention will be explained in detail below using drawings and the like. Figures 1 to 3 show the cell structure of the foam of the present invention.
This is an example of an enlarged view taken from the three sides of a rectangular parallelepiped in the three axes (X, Y, and Z axes) that are orthogonal to each other. The structural state as seen in the figure is shown below. Moreover, FIG. 4 is a conceptual diagram for the purpose of deepening the understanding of expressions of the above-mentioned X, Y, and Z axis directions and the bubble size measurement direction (x, y, z) described later. In FIGS. 1 to 4, the synthetic resin foam referred to in the present invention is a foam having a cell structure rich in closed cells and having a rectangular parallelepiped-like outer shape. The bubble film has a considerable number of wrinkles. Generally, the cell shape of synthetic resin foam is
Since it is said to have an approximately dodecahedral shape, it is difficult to accurately determine the location of the wrinkles structurally and quantitatively. So this, above, X,
When expressed as a whole when viewed from the three directions Y and Z, wrinkles can be seen in the air wall when viewed from any axial direction (see Figures 1, 2, and 3), but the direction of the wrinkles and the existing air bubble wall differ. If you closely observe the bubble walls in the Z-axis direction (Figures 1 and 2) and the X-axis direction (Figures 2 and 3), there are many wrinkles in each direction.
It can be seen that there are not many wrinkles on the cell wall in the axial direction (FIGS. 1 and 3), indicating that the wrinkles on the cell wall have distribution and directionality. The distribution and directionality of these wrinkles are considered to be special wrinkles formed by the foam manufacturing method of the present invention, which will be described later, and furthermore, the wrinkles themselves are dependent on the density, cell size, and shape of the foam. Therefore, it is thought that this is the source of exhibiting large elongation properties only in the X-axis and Z-axis directions, while having various properties. Next, we will discuss the relationship between the structure and various properties of the synthetic resin foam of the present invention, which has wrinkles on its cell walls in specific biaxial directions and has large elongation properties only in those directions. First, the density D [Kg/
m ³ ] and the bubble size, especially the bubble diameter y measured in the Y-axis direction
[mm], compressive strength in the Y-axis direction [Kg/cm ² ] to predict creep resistance, and tensile strength in the X- and Y-axis directions to predict the fracture resistance of the foam during use. We focused on strength [Kg/cm ² ], variation in tensile strength in both directions [%] and thermal conductivity [kcal/mhr℃] to predict the uniformity of performance, and evaluated the results using the method described in the main text. It is shown in Table 1. Fifth
The figure shows the overall evaluation of the results in Table 1 in coordinates with the vertical axis representing the foam density (D) [Kg/m ³ ] and the horizontal axis representing the bubble diameter (y) [mm] in the Y-axis direction. It is an analysis diagram stratified into those that achieve the object of the present invention (○ mark), those that are more preferable (◎ mark), and those that cannot achieve the object (x mark). According to the analysis results in Figure 5,
A foam that achieves the objects of the present invention has a foam density D
[Kg/m ³ ] is in the range of about 20 to 100, and the bubble diameter y [mm] measured in the Y-axis direction is in the range of 0.05 to 1, and between the two, (-75log y + 55)D (-5log y+20) must be satisfied. In order to achieve all of the above evaluation characteristics at a higher level, the density D [Kg/m ³ ] must be approximately 23 to 93, the bubble diameter y
It can be seen that it is more preferable that [mm] is in the range of 0.07 to 0.8 and satisfies the relationship (-75log y+48)D(-5log y+23). According to the inventors' experiments, the above relational expression is y
It has been confirmed that even the case of =0.05 is sufficiently satisfied. Next, the bubble density (D) and bubble diameter (y) described above
In addition, the relationship between the bubble diameters x and z measured in the X-axis direction and the Z-axis direction and the bubble diameter y in the Y-axis direction, that is, the present invention The size and shape of the cells, y/x and y/z, that the foam should have were examined and evaluated using the method described in the text. The evaluation items we focused on were compressive strength (Y-axis direction), tensile strength (X and Z
(axial direction), variation in tensile strength (X and Z axis directions)
and thermal conductivity (Y-axis direction), and the results of their evaluation using the methods and criteria described in the text are shown in Table 2, and their comprehensive evaluation is based on the following criteria (hereinafter, comprehensive evaluation will be based on this standard). I have also included the results that were carried out in accordance with the following. ◎: All are marked with ○ and are the most preferred. 〇: There is a △ mark, but the purpose is achieved in practical terms. ×: There is at least one × mark, and the purpose cannot be achieved. According to the results in Table 2, the foam required for the present invention has a foam density D [Kg/
m ³ ] is approximately 20 to 100, and the bubble diameter y measured in the Y-axis direction
[mm] is in the range of 0.05 to 1, and between the two, (-75log y+55)D(-5log y+20)
Even if all of the following relationships are satisfied, the size and shape of the bubble must be y/x1.05 and y/z1.05. In order to achieve all of the above evaluation characteristics at a higher level, the bubble size and shape should be y/x1.10,
It can be seen that y/z is preferably 1.10, and that it must be an aggregate of bubbles with a longer diameter along the Y axis. However, foams with y/x and y/z of more than 4 tend to have poor balance in dimensional stability, coefficient of linear expansion, compressive strength, tensile strength, etc., so care must be taken. Next, the relationship between the foam density D [Kg/m ³ ], the cell diameter y [mm] in the Y-axis direction, and the cell diameters x, y,
Since we have considered a foam that satisfies all the relationships between dimensions and shapes of z, y/x and y/z, we have investigated the wrinkles, locations of wrinkles, and wrinkles in the bubble membrane described in Figures 1 to 3. This is an attempt to comprehensively evaluate the condition, etc. However, since the cells of the foam are small and have a multifaceted shape as described above, it has been extremely difficult to quantitatively express them in terms of shape and structure. As a result of various studies, the present inventors determined the water vapor transmission rate measured in the Y-axis direction (in other words, are there any cracks or tears in the wrinkles?), and the water vapor transmission rate when stretched in the triaxial direction. It was finally determined that characteristics such as each elongation rate at break (in other words, are the wrinkles stretchable? What is the location and distribution of the wrinkles?) can be used as one of these structural indicators, and the wrinkle structure can be segmented. It was a success. The evaluation item we focused on was the elongation rate at break on the X and Z axes, which indicates how uniform the elongation rate is within the cross section.
Variation in Ex and Ez [%], Y indicating deterioration of insulation performance due to moisture absorption during long-term use in the Y-axis direction
The radial change ratio of thermal conductivity in the axial direction is approximately -160℃, which indicates crack durability when used as a heat insulator for liquefied natural gas tanks and as a heat insulator for liquefied nitrogen tanks in panel form. Cryogenic suitability at 196°C was selected as an evaluation item, and the results of evaluation according to the evaluation method described in the text and the comprehensive evaluation of those results using the same criteria described above are shown in Table 3. Figure 6 is a reference diagram to help you better understand the results in Table 3, and shows the elongation at break measured in the Z-axis direction on the vertical axis.
Ez [%], the horizontal axis is the elongation at break Ex [%] measured in the X-axis direction, and the overall evaluation results in Table 3 are plotted by stratifying them with ◎, 〇, and × marks. Also, Figure 7 shows the results of Table 3, X, Y,
Distribution of the elongation at break Ex, Ey, Ez on the Z axis, that is, the elongation at break Ex, Ez on the X and Z axes, which have large elongation characteristics.
In order to deepen the understanding of the relationship between the elongation rate Ey and the elongation rate Ey at break in the other axis (Y-axis) direction, which has small elongation properties, The axis shows the ratio of elongation at break between the X and Y axes, Ex/Ey.
The overall evaluation results for each of the foams in Table 3 are plotted with ◎, ○, and × marks as a scale. According to the results shown in FIG. 6, the foam that achieves the purpose of the present invention is 60Ex8 [%] and 60Ez8
Within the [%] range, the following relationships must be satisfied between Ex and Ez: (8Ex-56)Ez(1/8Ex+7) and Ez(90-Ex). Indicated by coordinate points (X-axis elongation at break Ex, Z-axis elongation at break Ez): (8, 8), 60, 14.5),
It is within the range of a pentagon connecting (60, 30), (30, 60) and (14.5, 60) with a straight line. Furthermore, a foam that satisfies suitability as a liquefied nitrogen tank insulation material and has the highest level of other properties also satisfies the Ez (52−Ex) relationship within the range of 40Ex12 [%] and 40Ez12 [%]. I know it has to be. Similarly, when expressed as coordinate points, it is within a range that includes the triangular line connecting (12, 12), (40, 12), and (12, 40) with a straight line. On the other hand, the elongation at break in the three axial directions, X, Y, and Z axes
According to the results shown in FIG. 7, which shows the relationships among the distributions of Ex, Ey, and Ez, the foam that satisfies the purpose of the present invention has a ratio of elongation at break of Ex/Ey and Ez/Ey of 8.3>
Ex/Ey>1.8, 8.3>Ez/Ey>1.8 and Ex+Ez<
It must satisfy the 12Ey relationship. In other words, when expressed as coordinate points (Ex/Ey, Ez/Ey), (1.8, 1.8)
, (8.3, 1.8), (8.3, 3.3), (3.3, 8.3) and (1.8
,
8.3) can be found in a pentagon connected by a straight line. Furthermore, regarding the water vapor permeability Py [g/m ² hr] in the Y-axis direction, which is an evaluation item in Table 3, the foam that achieves the objective of the present invention has , it can be seen that this value needs to be at least 1.5 or less. If you place importance on maintaining long-term insulation performance,
It is even better if the value of Py is 1.0 or less. Combining the results of FIGS. 6 and 7, which are the results of Table 3, and the results of the water vapor permeability Py [g/m ² hr] in the Y-axis direction, the foam for achieving the present invention can be Even if the results in Tables 1 and 2 are fully satisfied, if the elongation at break Ex, Ey, and Ez of the 56) Ez (1/8Ex+7) and Ez (90−Ex) and 8.3>Exx/Ey>1.8,
8.3>Ez/Ey>1.8 and Ex+Ez<12Ey, and the water vapor transmission rate [g/m ² hr] in the Y-axis direction must be 1.5 or less. In order for the foam of the present invention to withstand the extremely low temperatures of liquefied nitrogen and to achieve the objectives of the highest level, which emphasizes maintaining long-term insulation performance, it is necessary to meet the results shown in Tables 1 and 2 while at the same time Ex, Ey and Ez are 40Ex12 [%],
The three axes (X,
It can be seen that it is more preferable if there is a distribution of elongation at break between Y and Z) and the water vapor permeability Py [g/m ² hr] in the Y-axis direction is 1.0 or less.

【table】

【table】

【table】

【table】

【table】

【table】

【table】

[Table] Table 4 shows all the evaluation characteristics referred to in the present invention and the comprehensive evaluation of a series of evaluations for each representative of the foam of the present invention and the comparative foam. This Table 4 is intended to objectively prove the validity of the fragmentary evaluation of each requirement in Tables 1 to 3. According to the results in Table 4, the foam of the present invention satisfies almost all of the target evaluation characteristics of the present invention with high values, while the comparative foam has the structure defined in the present invention. It can be seen that the lack of one of the requirements results in a foam that does not meet the target properties. It can be seen that this result is completely consistent with the results in Tables 1 to 3.

【table】

[Table] Next, regarding the foam of the present invention and comparative foam,
In order to study the workability, workability, and function as a heat insulating material under extremely low temperatures when applying these materials to a cylindrical body to be insulated, we used a cylindrical body with an outer diameter of approximately By applying it to a 114mm (100A) pipe, the method described in the text improves the bending workability of the pipe surface, the heat formability in the pressed and bent state,
Table 5 evaluates the thermal insulation properties under extremely low temperatures and crack resistance, and also shows the comprehensive evaluation thereof. As can be seen from the comprehensive evaluation in Table 5, it exhibits excellent bending workability, thermoformability, and workability into small-diameter pipes, and the shaft can be bent according to the outside diameter of the pipe and the thickness of the foam. It can be seen that by adjusting the elongation rate in the direction, it is possible to create a pipe cover that does not require a large force when wrapping, does not generate minute cracks during the pressing and bending operation, and does not deteriorate its insulation performance. In a thermal cycle test using cryogenic fluid,
Only the foam of the present invention exhibits the targeted performance,
Compared to conventional foam, it has been found that it exhibits particularly surprising properties as a single cryogenic insulation material without the need for composites such as reinforcing materials. Considering its function as a heat insulating material, it can be seen that it is an innovative insulating material for cryogenic pipe covers, cylindrical tanks, spherical tanks, etc.

【table】

[Table] Next, instead of the polystyrene resin foam used in Tables 1 to 5, a commercially available vinyl chloride resin foam was molded using the extrusion foaming device used in Examples 1 to 4 under almost the same conditions. Methyl methacrylic acid resin foam was used as a material for press processing and was press-processed using the apparatus (Fig. 9) and method (Table 9) implemented in the present invention, and it was found that it met the criteria for the foam of the present invention. This was done to evaluate whether it is possible. According to the results in Table 6, which were evaluated with all the necessary structural factors and evaluation characteristics of the foam of the present invention being the same,
In addition to polystyrene, the resin constituting the foam of the present invention may include vinyl chloride resin, a blend thereof with inorganic substances, and methyl methacrylic resin that meet the evaluation characteristics targeted by the present invention and can be pressed and bent into a cylindrical body. I found out that it can also be done easily.

【table】

[Table] Next, the bead-shaped styrene foam was processed on the X and Y axes using a pressing device (Fig. 33) different from the pressing device (Fig. 9) used in the Examples and Comparative Examples of the foam of the present invention. Table 4 shows the foams of the present invention that were press-processed in two axes, and for comparison, the foams that were press-processed only in the X-axis direction and in all three axes, X, Y, and Z. All requirements and evaluation characteristics were evaluated in the same manner, and the comprehensive evaluation results are shown in Table 7. As is clear from the results in Table 7, it can be seen that the lack of one of the constituent requirements of the present invention resulted in a foam that could not satisfy the target properties. The reason why the elongation at break in the X-axis and Y-axis directions is sufficiently large but it cannot withstand the extremely low temperature of -196℃ is because a very large compression ratio (80%) is applied many times (3 times). Due to the pressing conditions, the tensile strength deteriorates significantly and the linear expansion rate becomes excessively high, causing the shrinkage rate of the foam at cryogenic temperatures to exceed the elongation rate at break under those conditions, resulting in cracks. It is considered that not only the characteristics of the pressed material but also
It is thought that the pressing method shown in FIG. 33 is also responsible.

【table】

[Table] The characteristics evaluated in Tables 1 to 7 are as follows:
Considering that most of these are representative properties for practical use of foam, such as push-bending workability, bending workability, cryogenic insulation suitability, etc., these results are not suitable for practical use of foam. This shows the adaptability itself. These foams are novel foams that have not been sufficiently researched in the past, and are suitable for transporting and storing low-temperature to cryogenic fluids such as liquefied petroleum gas, liquefied ethylene, liquefied natural gas, liquefied oxygen, and liquefied nitrogen. Nowadays, as insulation of pipes, cylindrical and spherical tanks, tunnels, and curved parts of buildings has become even more important, it is important to install synthetic resin foam in close contact with these structures. Easier than ever
Since it can be carried out over a wide range, economically, and reliably, it can be said that the foam is extremely useful. Furthermore, the foam of the present invention has great elongation properties in two axial directions and excellent compression properties in the remaining uniaxial direction, so that it can be used in combination with various materials,
Many applications such as use as a panel structure are possible. The foam of the present invention having the above-mentioned structural requirements can basically be produced by moderately pressing a synthetic resin foam molded product in biaxial directions.
In order to obtain a high-quality foam such as that of the present invention, care must be taken because the above-mentioned structural requirements cannot be met unless the manufacturing technology is properly selected. For example, regarding a polystyrene extruded foam molded board, it is manufactured by first pressing in the X-axis direction and then pressing in the Z-axis direction. To enumerate the main points in manufacturing, for example: a) Select a material foam with a cross section as homogeneous as possible. b) Select a material foam that has cells with long dimensions in the Y-axis direction. c) Select a new foam material after foam molding. d) Devise a pressing device with less slip. e) Shorten the actual length of the foam portion where pressing is performed. F) Set a longer pressing duration. g) When obtaining a foam with high elongation, press in stages. Conditions that satisfy at least five, preferably all, conditions should be established. 8 and 9 are principle diagrams of a device for pressing foam, in which the foam is pressed by a pair of upper and lower drive rollers 1, 2 or nipping drives 9, 10, and another pair of drive rollers 3 at the rear. , 4 or the clamping drive body 11,
A driving speed difference is provided between 12 and 12, and with that speed difference,
Pressure processing is performed on the axis in the conveyance direction, and then pressure processing is performed on another axis in the other direction perpendicular to the processed direction using the drive speed difference between the rollers or the nipping drive body in the same manner as described above. It becomes a foam with high elongation properties in biaxial directions. Reference numbers 5 and 6 in Fig. 8 and 13 and 14 in Fig. 9 refer to clamping devices in the Y-axis direction for transporting the foam while preventing it from slipping in each driving section. Since the pressure advances in the direction, sufficient adjustment is required. Hereinafter, the above-mentioned phenomena (a) to (g) in biaxial pressing performed using the apparatus shown in FIGS. 8 and 9 will be described. First, regarding a), while holding it in the Y-axis direction,
Since the other two axes are press-processed one by one, it is necessary that there be little variation in mechanical strength, especially compressive strength, within the cross section. Next, FIG. 10 is a diagram showing an example of the relationship between the cell shape of the foam material and the water vapor permeability in the Y-axis direction of the foam material after pressing. The physical properties of this material foam maintain a density of 27Kg/ ^m3 and a cell diameter of y≒0.6mm.
It was adjusted so that y/x≒y/z=0.7 to 2, and after one day, it was pressed in the order of the X axis and then the Z axis. Elongation at break on the X-axis and Y-axis of the obtained foam
Ex and Ey showed values of approximately 20% and 16%, respectively. According to Figure 10, the material foam has y/x≒y/z
It can be seen that it is better to select a foam having a cell structure in which the diameter is about 1 or more, that is, the long diameter is in the Y-axis direction. Figure 11 shows the number of days elapsed from foam molding to pressing processing and the water vapor permeability of the resulting foam.
In the diagram showing the relationship with Py, the material foam has a density of 27Kg/m ³ ,
The bubble diameters x, y, and z are 0.55 mm, 0.72 mm, and 0.58 mm, respectively.
The X-axis and Z-axis fracture elongation rates Ex and Ez of 100mm thick slices into 25mm slices after pressing are approximately 20 each.
% and 16%, the pressing compression ratio was selected to be 20% to 37% and the number of pressing processes was 1 to 3 times. Figure 12 is an example of the relationship between the elapsed number of days after foam molding and pressing processing of the foam and the elongation at break Ex on the The material for processing was sliced to a thickness of 25 mm, and the pressing conditions for each thickness were constant (compression rate of 37% x 1 time on both the X and Y axes), and the elongation at break was It is expressed by dividing it into 25 mm and 100 mm, represented by the axis value Ex.
%showed that). It has been found that the effects of changes over time on the X- and Z-axes on elongation at break are approximately the same. According to the results shown in Figures 11 and 12, in order to obtain a foam with excellent elongation properties and water vapor permeability, it is necessary to
It can be seen that it is preferable to use a material foam that has elapsed within a few days, preferably within 3 days. Figure 13 is a comparison diagram of the amount of thickness reduction [mm] in the Y-axis direction that occurs when foamed materials having different thicknesses are processed using the pressing devices shown in Figures 8 and 9. Using materials with the same physical properties as in the experiment shown in Figure 11, 100 mm thick specimens were sliced and laminated (point bonding with a small amount of adhesive was used to minimize the effect of the adhesive layer) to form the test material. Reworked. The pressing conditions were the same for each device, each thickness, and the same compression ratio of 20% for both the X and Z axes, and the processing test was performed in the order of the X axis → Z axis. The △ mark indicates the case of the apparatus shown in FIG. 8, the ○ mark indicates the case of the apparatus shown in FIG. 9, and the dotted line indicates the thickness region that cannot be processed. According to FIG. 13, in the apparatus of FIG. 8, the thickness of the foam decreases significantly during processing, and as soon as it becomes thick, slip occurs between the roll and the material, making it impossible to process. In addition, it can be seen that pressing with the apparatus shown in Figure 8 is not preferable for foams with a large thickness reduction rate, since compression characteristics, elongation characteristics, and their dispersion in the Y-axis direction, and water vapor permeability deteriorate. . on the other hand,
The device shown in Figure 9 can easily press a thickness of 300 mm, and can process almost all Y-type materials, from thin to thick.
It can be seen that this is an excellent device that can perform processing without deteriorating the compressive strength in the axial direction. Fig. 14 shows the relationship between the X-axis elongation at break of the foam by adjusting the distance between the two pairs of clamping drive bodies (indicated by the press distance ←→ mark) using the apparatus shown in Fig. 9. This is an example diagram, and the physical properties of the foam material and pressing conditions used are the same as in the experiment in FIG. 11. At this time, Ex and Ez were approximately 20% and 16%. According to Figure 14, the pressing distance is at least 300
It turns out that it is best to adjust it to less than mm, preferably less than 200 mm. Figure 15 shows the pressing duration [seconds] and elongation rate at break by the rear gripping drive using the device shown in Figure 9.
This is an example diagram showing the relationship with Ex [%]. The experiment was conducted using the same foam material of 100 mm as in the experiment in Figure 12, and the compression ratio and compression order, and is represented by Ex. According to FIG. 15, the pressing duration should be at least 1 second or more, preferably 2 seconds or more. Figure 16 is an example diagram showing the relationship between the machining order of the same axis (in this case, the Z axis) and the variation [%] of the elongation at break Ez when machining is performed using the apparatus shown in Figure 9. Three different materials were used at the same compression rate (compression rate = 20%). Variation [%] of the elongation at break Ez when the Z-axis is first pressed and elongation at break Ez when the Z-axis is pressed after processing the X-axis
This is a graph showing the variation [%].
The values of elongation at break Ez and Ez in this experiment are 15 each.
~16%, between 14 and 16%. According to FIG. 16, there is less variation in the elongation at break when the material is processed second than when it is processed first, and it is reduced to about 1/2. These results are simply the results of a simple comparison with the optimum conditions set for each item other than the items to be considered, and it is important to note that these factors may work in combination if they are not manufactured with these factors in mind. Therefore, it is easy to imagine that the quality of the final foam would be different. The term "synthetic resin foam" as used in the present invention refers to one having a closed cell structure, and includes foam molded products such as beads and extruded foam molded products, and most preferably refers to extruded foam molded plates. In addition, the synthetic resins constituting these foams are resins whose main components are styrene, vinyl chloride, vinylidene chloride, methyl methacrylate, and nylon, or copolymers or blends of these with copolymerizable materials. Also includes things. A more preferred resin is a resin containing styrene as a main component, but other styrene monomers such as α-methylstyrene, vinyltoluene, chlorostyrene, etc. may be used instead of styrene. In addition, monomers copolymerizable with the above styrene monomers, such as acrylonitrile, methacrylonitrile, methyl acrylate, methyl methacrylate,
Copolymers of maleic anhydride, acrylamide, vinylpyridine, acrylic acid, methacrylic acid, etc. are included. Furthermore, the above-mentioned styrenic polymer may be blended with other polymers to the extent that its properties are not impaired. Most preferred is polystyrene consisting of a single styrene monomer. Among polystyrenes, it is preferable to select one having a styrene monomer content of 0.3% by weight or less and a styrene trimer content of 0.5% to 1.5% by weight. If the foam is within this range, the cell diameter density within the cross section will be uniform, and the foam will have high asphalt heat resistance and durability against repeated compressive strain. In particular, the foam of the present invention, which achieves the goal by pressing in two specific axial directions, requires the above-mentioned materials and is a very convenient polymer. In addition, the measurement and evaluation of each characteristic in the present invention is as follows:
I did it as follows. (1) Density [Kg/m ³ ] A product having a cross section of about 100 mm thick and about 300 mm wide, obtained by removing the skin from the upper and lower surfaces in the thickness direction and both sides in the width direction of the extruded foam base plate as shown in Figure 17. As shown in Figure 16, divide the width direction and thickness direction into 3 and 2 parts, take 3 pieces (LCR) in the width direction from the upper part in the thickness direction, and calculate the volume V.
Find the density D [Kg/m ³ ] from [cm ³ ] and weight [g]. (2) Bubble diameter [mm] For each direction (X, Y, and Z) shown in Figure 4, the bubble diameter x, y, and z [mm] in each direction is
According to the measurement method specified in ASTM D2842, the 19th
From the positional relationship shown in the figure, take a total of 3 test pieces (n = 3) from each side in the width direction (LCR), and determine the average values of the bubble diameters x, y, and z [mm] on the X, Y, and Z axes. (3) Bubble shape; y/x and y/z Calculate the ratio y/x and y/z of the average values of x, y, and z obtained by the above method. (4) Compressive strength [Kg/cm ² ] Samples with the positions and dimensions shown in Figure 18 were taken, one each from L, C, and R from the width direction, and two from each length, making a total of 6 test pieces. The compressive strength in the Y-axis direction is measured using the ASTM D 1621 measuring method, expressed as an average value, and evaluated using the following criteria.

[Table] (5) Tensile strength [Kg/cm ² ] and variation [%] After adjusting the test piece to 50 mm x 50 mm x 50 mm according to Figure 20 based on ASTM D-1623B method, LCR
A total of 12 test specimens, 4 of each, were bonded with jigs on the upper and lower surfaces of which the tensile strength was to be measured. The average value and variation of the tensile strength on the X-axis and Z-axis are calculated by the following method and evaluated based on the following criteria. Tensile strength (average) = sum of individual data / 12 [Kg/cm ² ] Variation in tensile strength = maximum value - minimum value / average value × 100 [%] [Unit of tensile strength; Kg/cm ² ]

[Table] (6) Thermal conductivity [kcal/m hr℃] Using the three test samples shown in Figure 21,
The value at 0°C is determined by the measurement method according to ASTM C-518, and the average value is evaluated based on the following criteria. If the width is insufficient, connect it with adhesive and use it as a test piece.

[Table] (7) Elongation at break [%] and variation [%] Based on the tensile strength measurement method, ASTM D 1623B method, the test piece is pulled in the specified directions (X, Y, and Z), and the strain at break is measured. Measure the amount (amount of elongation) [mm] and calculate and evaluate using the following formula. A total of 12 test pieces were prepared in each direction based on Figure 20.
Individual. Elongation at break = Elongation at break [mm] / Thickness of test piece [mm] x 100
[%] Variation in elongation at break from the 12 pieces of elongation at break data = maximum value - minimum value / average elongation rate [%] x 100 [%]

[Table] (8) Ratio of elongation at break: Ex/Ey and Ez/Ey Calculate the respective ratios Ex/Ey and Ez/Ey from the average values of 20 elongation at break Ex, Ey, and Ez. (9) Water vapor transmission rate; WVTR [g/m ² hr] Three test pieces of 25 mm x 80φ are taken according to the sampling procedure shown in Figure 25, and measured according to ASTM D 355. WVTR at 25mm thickness is calculated using the following formula. However, it is carried out using a method using distilled water. WVTR [g/m ²・hr] = G / A ・t G: Weight change [g] t: Time span during which G occurred (hr) A: Transmission area (m ² ) (10) Thermal conductivity over time Rate of change A test piece of 25 mm in thickness, 200 mm in width, and 200 mm in length is taken from the top of the pressed product as shown in Figure 21, and measured using the apparatus shown in Figure 22. Water 28 at 27° C. is placed in a container 25 equipped with a temperature controller 27 surrounded by a heat insulating material 26, and the opening side of the container is sealed with the gasket 3 using the sample piece 29.
Block through 0. At this time, the sample piece is placed so that there is a distance of about 30 mm between the bottom surface of the sample and the water surface in the container. Further, the upper surface of the test piece 29 is in close contact with a cooling plate 33 that is cooled to 2° C. by cooling water that is circulated from circulating water ports 31 and 32. After being left in this condition for 14 days, the surface of the sample piece was wiped gently with gauze, and the thermal conductivity λ' of this piece was measured in accordance with ASTM C 518, and the thermal conductivity λ' was measured under the same conditions before the test. The rate of change from the thermal conductivity λ is λ′/λ
Calculate and evaluate according to the table below.

[Table] (11) Panel cryogenic resistance As shown in Figure 24, 50 mm x test plate width (170
270mm) x 300mm, and after cutting and finishing the upper and lower surfaces, test foam 35 with the X-axis and Z-axis directions clearly marked as shown in Figure 25, was 12mm x (170mm)
270mm) x 300mm plywood (JAS standard product) 37.3
8 is a polyurethane-based two-component cryogenic adhesive (manufactured by Sumitomo Bakelite Co., Ltd.: Sumitaku EA90177) 3
6 and heat-cured under a pressure of 0.5 Kg/cm ² for 24 hours at 23° C. to prepare three test panels 34 and test them. 1) Cryogenic temperature: -160℃ test As shown in Figure 26, the above test panel 3
4 was suddenly put into a cryogenic chamber 39 whose internal temperature was controlled to -160°C±5°C, and after being left for 5 hours, it was rapidly brought back to room temperature and left to stand for 1 hour. Repeat this operation 4 times, and the cryogenic chamber 39
Immediately after taking out the test panel 34 from the test foam board 35, the four sides of the test foam board 35 are observed to confirm the presence or absence of cracks and the direction in which they occur. After 1 hour, the plywood 37, 38 and the test foam board 35 were sliced with a single-tooth slicer along the interface, and then sliced into the test foam board 35 to a thickness of about 10 mm.
The divided slice samples are prepared, water mixed with a surfactant and coloring ink is applied to the surface of each slice sample, and the presence or absence and direction of cracks on the sample surface are investigated and recorded. The temperature inside the cryogenic chamber 39 is controlled by the liquid nitrogen pipe 4 from the liquid nitrogen cylinder 40.
1 to a jet nozzle 43 at the top of the tank, where it is vaporized while contacting a perforated barrier plate 44, and the gas exits from an outlet 46 to lower the temperature inside the tank. The flow rate of liquid nitrogen is regulated by opening and closing an automatic flow rate control valve 42 by a control device that interlocks a thermometer 45 in the tank and a timer. 2) Cryogenic temperature: -196 test As shown in FIG. 27, the test panel 35 described above is tested in a liquid nitrogen immersion device 48 sealed with a heat insulating material 47. After introducing liquid nitrogen 50 directly from the liquid nitrogen cylinder into the stainless steel deep-bottom tray 49 via the liquid nitrogen piping 41 and liquid nitrogen introduction valve 51, the test panel 34 is rapidly and sufficiently immersed in the liquid nitrogen 50. A steel weight 52 that has been cooled in liquid nitrogen in advance is placed on top of the iron support 51, and after being continuously immersed for 30 minutes, the test panel 34 is taken out into an ambient atmosphere and left for one hour while being ventilated. . This operation was repeated four times, and the existence and direction of cracks on the outer and inner surfaces of the foam were investigated and recorded using the same equipment and method as used in the cryogenic -160°C test. Each test temperature condition will be evaluated according to the following criteria based on the results of the investigation records of the three test panels.

[Table] (12) Pipe bending workability As shown in Figure 28, test foam thickness (25, 37.5 and 75 mm) x width (200 mm) x length (500 mm)
After adjusting the evaluation sample 53 with a diameter of about 114 mm (100 A) shown in FIG. -A line). The bending workability is evaluated based on the following criteria.

[Table] (13) Pipe cover thermoformability As shown in Fig. 30, the test foam 53 was pressed so that the X-axis direction was perpendicular to the outer diameter (114 mm, 100 A) of the iron pipe 54 for thermoforming. After bending
After completely covering the 0.3 mm galvanized iron plate 55 on the pressed and bent test foam 56, the tension band 5
After fixing both ends in step 7, place it in a hot air oven adjusted to 85℃ with the foam part at the top, heat it for 45 minutes, then take it out and leave it to cool in the air for 2 hours. The galvanized iron plate 55 is removed, and the gaps 58 and 59 between the outer surface of the pipe and the molded body 56 are measured and recorded in mm on the semicircumferential diameter line A-A stamped on the pipe. The gap to be evaluated is expressed as the average of recorded gaps 58 and 59. The results will be evaluated based on the following criteria.

[Table] (14) Pipe cover insulation properties 2 materials with thickness 37.5 mm x width 200 mm x length 500 mm
Make one sheet, and one of them has an outer diameter as shown in Figure 29.
A 114 mm pipe is pressed and bent in the X-axis direction along its curvature, and then another sheet is placed in the same direction on top of the first sheet that has already been pressed and bent, creating two layers of pressing and bending, as shown in Figure 30. Applying the thermoforming pipe cover manufacturing method shown in Figure 2, thermoforming is performed under the conditions of heating at 85℃ x 45 minutes and cooling for 2 hours, and adjusting it to a 1/2 arc-shaped pipe cover with a length of approximately 200 mm. Pipe covers 61, 62 for the first layer and pipe cover 64 for the second layer,
65 are prepared, and the cross-sectional structure 60 shown in FIG. 31 is constructed in the following manner. A pair of 1/2 arc-shaped first layer pipe covers 61, 62 are made of stainless steel 304 pipe, 54
(diameter 100A, length approximately 800mm), and the joints were glued and fixed with a polyurethane cryogenic adhesive (Macroplast UK8605P/UK5400 manufactured by Henkel, West Germany), and in the same way as shown in the side view of Figure 32. Construction of the first layer will be completed. The same adhesive is used for the joints 69 between each pair of pipe covers and the joints 71 between the partition flanges 70. Next, the second layer pipe covers 64, 65, etc. are sequentially installed while shifting the joints in the longitudinal direction and circumferential direction so that they do not overlap. Approximately 2.5 mm of polyurethane mastic (manufactured by Nichias Corporation: Elastonato A No. 9840A) is applied to the outer surface of the second layer.
mm to form a moisture-proof layer 66. After being heated for 4 days, the cryogenic practical piping test device 67 shown in Fig. 32
The liquid nitrogen 50 is rapidly introduced from the liquid nitrogen cylinder 40 through the flexible pipe 41 and the manual valve 42 to maintain the inner surface at -196°C for 6 hours, and the liquid nitrogen 50 inside is connected to the valve 6.
At step 8, the container was suddenly removed, emptied, and left to rise naturally in a 23°C x 80% (humidity) atmosphere for 12 hours. Repeat this operation three times in total and observe the surface condition on the moisture-proof layer of the test piece to determine whether there is surface condensation or not.
Record the presence or absence of icing and evaluate based on the following criteria.

[Table] (15) Pipe Cover Cracking Resistance Immediately after completing the above-mentioned pipe cover insulation test, carefully disassemble the cold storage part on the cryogenic practical piping test device 67, and crack the first layer of pipe cover 6.
1st, 62nd group and 2nd layer pipe covers 64, 6
The inner and outer surfaces of Group 5 were observed, and the presence or absence of cracks and the direction of the cracks were checked visually or with the color check used in the "panel cryogenic resistance" evaluation test. The results were recorded and evaluated according to the following criteria.

[Table] The measurement method for the typical characteristics of the styrene resin used in the Examples and Comparative Examples for producing the foam of the present invention is described below. Polymer viscosity The intrinsic viscosity of toluene at 30°C was approximately 0.83. Styrene monomer The amount was determined by gas chromatography (detector FID) and was 0.20% by weight.Styrene trimer The polymer was dissolved in methyl ethyl ketone, and methanol was added to precipitate the polymer content.
The supernatant liquid was collected using silicone DC-410/Chromosorb.
-The value was determined by gas chromatography filled with W (detector FID) and was 0.87% by weight. Example 1 A styrene resin containing a styrene monomer content of 0.20% by weight and a styrene trimer content of 0.80% by weight was produced using a screw type extruder, a blowing agent injection mixer, a cooling machine, and a die for forming a plate-like object. Foaming was performed using an extrusion foaming device. 100 parts by weight of polymer, 2 parts by weight of flame retardant, nucleating agent
A raw material consisting of 0.03 to 0.1 parts by weight is continuously fed to the screw hopper section of the extruder, and a mixed blowing agent consisting of dichlorodifluoromethane and methyl chloride (1:1) is added in a blowing agent injection mixer of 12 to 17 parts by weight. was injected under pressure. The resulting mixture was then mixed and cooled under pressure in a cooler, and the resin temperature was finally adjusted to 90 to 118°C. Subsequently, the foaming agent-mixed resin was extruded from a die under atmospheric pressure, and at the same time a foamed material for press processing was obtained. At this time, the bubble shapes y/x and y/z consisting of the bubble diameters x, y, and z are 1.1 to 1.25 and 1.1 to 1.25, respectively.
1.17, the cross-sectional size was kept constant at approximately 110 mm x 350 mm, the manufacturing conditions were adjusted, and the bubble diameter y
and density D are adjusted respectively, 0.07 to 1.6 mm, approximately 2.15
Foams ranging from ~77Kg/ ^cm2 were obtained. For those with a density of 21, Kg/ ^m3 or less, an additional 2
Secondary foaming with steam at 100℃ for ~6 minutes, approx.
The density was adjusted to 15.5-20Kg/m ³ to create a special low-density material. From these extruded plate-like bodies, the cross section shown in FIG.
A material for press processing of 100mm x 300mm x 2000mm was manufactured. These materials were pressed in the X direction and then in the Z axis direction using the mechanical pressing device shown in FIG. 9 according to the manufacturing method described in the text. In particular, the main conditions at this time were as shown in Table 8. Cell shape of product after pressing process y/x, y/
z was almost constant in the range of 1.2 to 1.4. The density, the cell diameter y in the D and Y directions, and the cell shapes y/x and y/z of the foams after the pressing process were measured by the methods described in the text. Furthermore, the compressive strength (Y direction), tensile strength (X and Z directions), and variation in tensile strength (X and Z directions) of these foams were investigated.
direction) and thermal conductivity (Y direction) were measured by the method described in the text and the evaluation results are shown in Table 1. That is, based on the overall results in Table 1, those that satisfy the purpose of the present invention (marked with ○), those that are most preferable (marked with ◎),
Those that do not meet the criteria (x mark) are classified, and the evaluation results are plotted with the density (D) [Kg/m ³ ] on the vertical axis and the cell diameter (y) in the Y-axis direction of the foam on the horizontal axis. The results of plotting on a graph and analyzing the distribution state are shown in FIG. According to the results shown in FIG. 5, the foam that satisfies the purpose of the present invention is expressed by coordinate points (bubble diameter y, density D):
(1.0, 55), (0.25, 100), (0.05, 100), (0.05
,
26.5) and (1.0, 20) with a straight line, more preferably (0.8, 55), (0.25,
93), (0.07, 93), (0.07, 28.5) and (0.8, 23.5
)
must be within the pentagonal range connected by straight lines. In other words, the foam of the present invention has a density D [Kg/m ³ ] of about 20 to 100 and a cell diameter y [mm] measured in the Y direction of about 0.05 to 1. The relationship between y and D is (-75log y+55)D(-5log y+20), and more preferably, the density D [Kg/m ³ ]
It is necessary that the bubble diameter y [mm] is in the range of 0.07 to 0.8, and that the relationship between y and D is (-75log y+48)D(-5log y+23). I understand. Table 8 Processing conditions Aging days until processing: 1 day Processing thickness: 100mm Processing speed (inlet belt): 12m/sec Compression ratio (inlet/outlet belt speed ratio): 22/21 to 28/21 Pressing distance (inlet, outlet) Distance between belt axes): 200 mm Pressure fixing time: 3.6 seconds Number of processing: 1 to 3 times Example 2 Styrene resin similar to Example 1 (styrene monomer: 0.20% by weight) (styrene trimer: 0.80% by weight) )
Using the same equipment and method, a material for pressing was manufactured. At this time, the material density was adjusted to about 21 to 55 Kg/m ³ and the bubble diameter y in the Y direction was adjusted to 0.1 to 0.75 mm, within the preferred value range of Example 1, and the bubble shape y/x, y/z
In order to study the influence of the . By combining these materials with the main processing conditions listed in Table 8 and the above materials using the mechanical pressing device shown in Figure 9 according to the manufacturing method described in the text, the bubble shapes y/x and y/z are formed. Biaxially pressed foams for evaluation were produced with values ranging from 0.8 to 3.25. In FIG. 5, which plots the results of Example 1, the obtained pressed foam has the most desirable range in terms of the relationship between the density D and the cell diameter y in the Y direction, that is, the coordinate points (0.8, 55), ( 0.25, 93), (0.07, 93)
,
It existed within a pentagon connecting (0.07, 28.5) and (0.08, 23.5) with a straight line. Table 2 shows the results of evaluating these foams in terms of cell shape y/x and y/z using the same evaluation items and criteria as in Example 1 according to the method described in the text. From the results in Table 2, it can be seen that the density D that satisfies the purpose of the present invention
[Kg/m ³ ] is about 20 to 100 Kg/m ³ and the bubble diameter y [mm] measured in the Y-axis direction is in the range of 0.05 to 1, and between y and D, (-75log y + 55)D (- 5log y + 20), the dimensions and shapes of the bubbles y/x and y/z are y/x1.05 and y/z, respectively.
Must be 1.05. In order to achieve a higher level of all the above evaluation characteristics, the bubble size and shape should be y/x1.10,
It can be seen that y/z is preferably 1.10. That is, the foam that achieves the object of the present invention to the highest level has a density D [Kg/m ³ ] of about 23 to 93 and a cell diameter y [mm].
is 0.07 to 0.8, and the relationship between the density D and the bubble diameter y in the Y direction satisfies (-75log y+48)D>(-5log y+23), and the bubble shape y/x1.1, y/z1.1
It can be seen that it is necessary to satisfy the following, and that it must be an aggregate of bubbles with a long diameter on the Y axis. Example 3 Using the same styrene resin as in Examples 1 and 2, the same extrusion molding apparatus and method were repeated to produce two types of material foams for press processing with the same cross section. The density D is 27Kg/m ³ and 50Kg/m ³ respectively, and the bubble diameter y in the Y direction is
They were 0.61 mm, 0.11 mm, and the bubble shapes y/x and y/z were 1.20 and 1.15, and 1.25 and 1.20, respectively. These materials are first pressed in the X direction and then in the Z direction using the pressing device shown in Fig. 9 according to the manufacturing method described in the text.
It was pressed in the direction. At this time, among the pressing processing conditions shown in the table, only the compression ratio and the number of processing times were selected as appropriate, and the other conditions were the same. /Ey,
An evaluation material was manufactured to examine the influence of Ez/Ey and water vapor transmission rate in the Y-axis direction. For comparison, the unprocessed one (experiment No. 113) and the one processed only in the X direction (experiment Nos. 124 to 127)
and those processed only in the Z direction (experiment Nos. 115 to 118) were also manufactured. For each foam, density D, cell diameter y, cell shape y/x and y/z,
Elongation at break in each of the X, Z and Y directions Ex, Ez,
Ey Measure the ratio of elongation at break in the X direction and the Y direction Ex/Ey, the ratio of the elongation at break in the Z direction and the Y direction, Ez/Ey, and the water vapor permeability Py in the Y direction [g/m ² hr],
Furthermore, the evaluation characteristics described in the main text, namely, the variation in elongation at break Ex and Ez in the X and Z directions, the rate of change over time of thermal conductivity in the Y direction, and -160°C and -196 in the X and Z directions.
Focusing on the cryogenic resistance of each material at .degree. C., the material was evaluated using the method and criteria described in the text, and the results of each material and the comprehensive evaluation thereof are shown in Table 1. That is, in order to better understand the results in the table, the vertical axis shows the elongation at break Ez [%] measured in the Z direction, and the horizontal axis shows the elongation at break Ex [%] measured in the X direction.
On the scale, those that meet the purpose of the present invention (○ mark), those that meet the highest standards (◎ mark), and those that do not meet (x mark)
Figure 6 shows the directionality of elongation at break of each foam. In addition, the ratio of the elongation at break in the Z direction and the Y direction, Ez/Ey, is shown on the vertical axis.
On the horizontal axis, the ratio of the elongation at break in the X direction and the Y direction, Ex/Ey, is scaled. Those that meet the purpose of the present invention (○ mark), those that meet the highest standards (◎ mark), and those that do not meet ( Fig. 7 shows the relationship between the elongation rate distribution in the X and Z directions, where the elongation is good, and the Y direction, where the elongation is very small. According to the results shown in FIG. 6, the foam that satisfies the object of the present invention has a relationship between the elongation at break Ex in the X-axis direction and the elongation at break Ez in the Z direction at least (8-Ex-56)Ez( 1/8Ex+7) and Ez(90−Ex), and Ez and Ex are each 60Ez
It can be seen that the values are distributed in the range of 860Ez8 [%]. When shown in terms of the relationship between the coordinate points (X-axis direction elongation at break Ex, Z-axis elongation at break Ez), (8, 8),
(60, 14.5), (60, 30), (30, 60) and (14.5,
60) must be within the range of a pentagon connected by a straight line. Furthermore, it further enhances its function as a cryogenic insulation material, -
The foam of the present invention, which is considered as a cold insulator for liquid nitrogen at 196°C and has other properties of the highest standard, has Ex, Ey
are respectively 40Ex12 and Ez in the range of 40Ex12
It must satisfy the relationship (52−Ex),
Similarly, if we show this using coordinate points, (12, 12), (40,
12) and (12, 40) with a straight line. On the other hand, the elongation at break between the three axes X, Y, and Z axes
According to the results shown in FIG. 7, which shows the relationships among the distributions of Ex, Ey, and Ez, a foam that satisfies the purpose of the present invention can satisfy the above-mentioned conditions and has a ratio of elongation at break of Ex/Ey,
Ez/Ey is 8.3>Ex/Ey>1.8, 8.3>Ez/
It must satisfy the following relationships: Ey>1.8 and Ex+Ez<12Ey. In other words, when expressed as coordinate points (Ex/Ey, Ez/Ey), (1.8, 1.8), (8.3, 1.8), (8.3, 3.3)
,
It can be seen that it is inside a pentagon connecting (3.3, 8.3) and (1.8, 8.3) with a straight line. Furthermore, regarding the water vapor permeability Py [g/m ² hr] in the Y-axis direction, which is an evaluation item in Table 3, the foam that achieves the purpose of the present invention has a foam that suppresses deterioration of the heat insulator during long-term use. It can be seen that this value needs to be at least 1.5 or less. If you place importance on maintaining long-term insulation performance,
It is even better if the value of Py is 1.0 or less. Combining the results of Figures 6 and 7, which are the results of Table 3, and the results of the water vapor permeability Py [g/m ² hr] in the Y-axis direction, the foam for achieving the present invention can be Even if the results in Tables 1 and 2 are fully satisfied, the elongation at break on the X, Y and Z axes Ex, Ey, Ez
are in the range of 60Ex8 [%] and 60Ez8 [%], respectively, and are in the range of (8Ex - 56) Ez (1/8 Ex + 7) and Ez (90 - Ez), and 8.3 > Ex / Ey
＞1.8, 8.3＞Ez／Ey＞1.8 and Ex＋Ez＜12Ey, and the water vapor permeability in the X-axis direction Py [g/m ²
hr] must be 1.5 or less. In order for the foam of the present invention to withstand the extremely low temperatures of charged nitrogen and to achieve the objectives of the highest standard, which emphasizes maintaining long-term insulation performance, it is necessary to satisfy the results shown in Tables 1 and 2. At the same time, Ex, Ey and Ez are 40Ex12
[%], 40Ez12 [%] and Ez (52-Ex), and 8.3>Ex/Ey>1.8, 8.3>Ez/
There is a distribution of elongation at break among the three axes (X, Y, Z) in the range enclosed by Ey > 1.8 and Ex + Ez < 12Ey, and the water vapor permeability in the X-axis direction Py [g/m ² hr]
It turns out that it is more preferable if is 1.0 or less. Figures 1, 2, and 3 are representative examples of the foam cell structure with high elongation characteristics in the biaxial direction as used in the present invention.
Enlarged photograph viewed in the X, Y, and Z axis directions (50x)
It is. 1 shows the X-axis direction, FIG. 2 the Y-axis direction, and FIG. 3 the Z-axis direction. Figures 1 and 2
According to Figures 3 and 3, when the state of the wrinkles inside the foam of the present invention is expressed as a whole when viewed from the three directions of the X, Y, and Z axes, the air walls are wrinkled when viewed from any axis. However, if you carefully observe the direction of the wrinkles and the existing bubble walls, you will notice that they are in the Z-axis direction (Figures 1 and 2).
There are many wrinkles on the cell wall in the X-axis direction (Figs. 2 and 3), but there are many wrinkles in the Y-axis direction (Figs. 1 and 3).
It is said that there are not many wrinkles on the bubble walls of
It can be seen that the wrinkles on the bubble wall have a distribution and directionality. The distribution and directionality of these wrinkles are considered to be special wrinkles formed by the foam manufacturing method of the present invention, and furthermore, the wrinkles themselves are caused by the density, cell size, and shape of the foam, Considering the relationship between Ex and Ez, the ratio relationship between Ex and Ey and Ez and Ey, and the relationship with water vapor transmission rate, these characteristics are related to the type of wrinkles and the distribution, direction, and amount of wrinkles described above. It can be seen that this is an important structural indicator of the foam of the present invention that indicates the condition. Example 4 In Examples 1 to 3, the relationship between the foam density D and the cell diameter y in the Y direction, the cell shapes y/x and y/z, the water vapor permeability Py in the Y direction, and the elongation at break in three directions Ex,
Since the relationship between Ez and Ey was evaluated individually, in order to improve the objectivity of these, the results of comprehensive evaluation of all the characteristics that the present invention should have for the foam of the present invention and the comparative foam are shown below. . That is, the styrene resins used are those of Examples 1 to 3.
Using the same material, the material foam density is approximately 16,
23, 27, 50 and 77Kg/m ³ , the bubble diameter y in the Y direction is approximately
0.1~1.35mm, bubble shape y/x approximately 0.75~1.25,
Material foams were produced using a combination of y/z of approximately 0.75 to 1.25. Furthermore, this material foam is processed by the method described in the text.
Selected from the main processing conditions in Table 8, comparison foams were press-processed only on either the .138 to 139) were added to prepare foams for evaluation shown in the foam structure and characteristics section of Table 4. All of the evaluation characteristics referred to in the present invention were evaluated for the above material foam and processed foam by the methods described in the text, and the results are shown in Table 4. Considering practicality, the criteria for comprehensive evaluation in Table 4 are as follows. ◎; All properties are ○; ○; △, but most of them are ○; ×; ×, according to the results in Table 4. In contrast, the comparison foam fails to meet the target evaluation characteristics because it lacks one of the constituent requirements of the present invention. You can see that it is. It can be seen that this result is completely consistent with the results shown in Tables 1 to 3 above. Example 5 Five types of foams of the present invention press-processed in Example 3, one type of biaxially press-processed foam that cannot achieve the purpose of the present invention for comparison, and one type that has high elongation properties only in the X-axis direction In order to evaluate the suitability of the foam of the present invention for application to pipe covers, cylindrical or spherical tanks, etc., three types of uniaxially pressed foams were used. The moldability, heat insulation properties, and crack resistance of the thermoformed pipe cover were tested and evaluated using the methods described in the text. The pressed foam used was sliced 100 mm thick into 25 mm, 37.5 mm, and 75 mm, and a combination was selected so that the total cold insulation thickness was 75 mm.
The pipe cover has a 1/2 arc-shaped pipe cover with a 1/2-arc shape and is machined in both the longitudinal and circumferential directions. It was used as a butting joint. The conditions of the experiment, the results of the evaluation items, and the overall evaluation results are shown in Table 5. According to the results in Table 5, the foam of the present invention, which has high elongation properties in the biaxial directions, can be applied to pipes as narrow as 114 mm by selecting the thickness and the elongation properties in the direction of pressure bending. It can be easily pressed and bent without applying any force, and if necessary, it can be thermoformed and fixed to easily create molded products with excellent workability.It is used as a cold insulator for pipes that are cooled to -196℃. Even with a thickness of 75 mm, it shows no surface condensation and is an excellent circular or spherical heat insulating material for extremely low temperatures that does not cause any cracks. Items that are pressed only in one axis satisfy the bending workability and thermoformability, but because there is no Z-axis elongation corresponding to the longitudinal direction of the pipe, the heat generated in the material at extremely low temperatures It can be seen that it cannot absorb stress and breaks due to cracks in the circumferential direction, or cracks occur in the diagonal direction as well, so it cannot fulfill its function as a heat insulator. Example 6 The following foam raw materials were used as foams made of polyvinyl chloride resin other than polystyrene and methyl methacrylic acid resin. Commercially available 50 mm x 600 mm x 900 mm Kregesel [manufactured by Kanegafuchi Chemical Co., Ltd.; #33] and 25 mm x 600 mm x vinyl chloride resin foam were used.
900mm Roxel board [Fuji Chemical Industry Co., Ltd.]
G500H] and a 50 mm x 300 mm x 900 mm methyl methacrylic resin foam board [prototype manufactured by Asahi Dow Co., Ltd.] were used as press processing materials and processed using the press processing device shown in Fig. 9 under the processing conditions shown in Table 9. , Pressed foam for evaluation 4
Seeds (Experiment No. 166-169) were obtained. Regarding these,
All the physical property items listed in Table 4 and the test evaluation items directly related to practicality were applied, and evaluations were made in the same manner using the methods and criteria described in the text, and the results and overall evaluation results are shown in Table 6. According to the results in Table 6, PVC foam (experimental
No. 166 & No. 167), a blend foam of vinyl chloride resin and an inorganic material (Experiment No. 168), and a methyl methacrylic acid resin foam can all be obtained to meet the requirements of the foam of the present invention. Example 7 Pre-expanded polystyrene particles with a density of 11.6 Kg/m ³ were filled into a mold, and 3
Steam of Kg/cm ² G is introduced for about 40 seconds to heat and expand the pre-expanded particles, and the particles are fused together to form a foamed styrene resin molded product, and the foamed styrene resin molded product is molded. The mold was removed from the mold and heat formed at 70°C for 12 hours. The size of the molded product at this time was 1840 mm x 930 mm x 425 mm. Next, the above-mentioned foamed styrene resin molded product was cut from the inside using a heating wire cutting machine.
I set it to 350mm. The density is 10.9Kg/m ³ , and the bubble diameters on the X, Y, and Z axes are 0.33mm, 0.31mm, and 0.32mm, respectively.
The average value is shown. This board-like foamed styrene resin molded product is placed on the lower press plate 77 and the formwork 73 and the upper press plate 7.
50 ton press machine 72 having a pressing part 74 at 6
The board-like foamed styrene resin molded product 75 is placed in the formwork 73 of the (pressing device shown in FIG. 33), and the board-like foamed styrene resin molded product 75 is compressed to a compressive strain of 90% on the X axis under a pressure of 40 kg/cm ² . Immediately after applying a compressive load in the direction, the upper press plate 76 was raised and this operation was repeated six times in succession. The size of the expanded styrene resin molded product obtained after compression in the X-axis direction is 350 mm x 350 mm x 262 mm, and the density is 14.5 Kg/m ³
It was hot. The pre-compressed expanded styrene resin molded product obtained was cut using a heating wire cutting machine to form a 350mm x 350mm
A board-shaped styrene foam resin molded product with a size of mm x 350 mm was made, and the board-shaped styrene foam resin molded product was placed in the mold of a 50-ton press machine having a mold and a pressing part, and the board was pressed at a pressure of 40 kg/cm ² . Firstly, the molded styrene foam resin is compressed to a compressive strain of 80%.
Immediately after applying a compressive load in the axial direction, the upper press plate was raised, and this operation was repeated three times in succession. Furthermore, the same compression was performed on the Z-axis direction surface of the board-shaped styrene foam molded product under the above conditions. The size of the obtained expanded styrene resin molded product is 324 mm ×
It was 350mm x 324mm and had a density of 13.6Kg/m ³ . The expanded styrene resin molded product obtained before compression was compressed on the X-axis and Z-axis using the same size and method as before, and then the Y-axis was also compressed under the same conditions. The size of the resin molded product is 324mm x 324mm x 324mm, and the density is 14.7Kg/
It was ^m3 . By the method described in the text applied to the foam of the present invention using the compressed materials obtained in Example 6 and, the cell diameter y, cell shape y/x and y/z,
Elongation at break in Z and Y directions Ex, Ez, Ey, ratio of elongation at break in X and Y directions Ex/Ey, ratio of elongation at break in Z and Y directions Ez/Ey, and water vapor transmission rate in Y direction Py was measured, and all evaluation characteristics described in the text used in Example 4 were evaluated, and the results and overall evaluation results are shown in Table 7. Necessary requirements for the foam of the present invention are density D, cell diameter y, cell shape y/x, y/z, elongation at break in three directions Ex,
Ey, Ez Ratio of elongation at break in three directions Ex/Ey, Ez/
Considering Ey and water vapor transmission rate Py,
It can be seen that the foam of the present invention lacks any of the requirements and thus fails to achieve its purpose.

[Brief explanation of drawings]

Figures 1, 2, and 3 are microscopically enlarged (50x) photographs of the foam particle structure of the present invention, and are representative photographs of the particle structure viewed from the X-axis direction, Y-axis direction, and Z-axis direction, respectively. , Fig. 4 is a conceptual diagram to deepen the understanding of the expression of the above-mentioned X, Y, and Z axis directions and the measurement directions (x, y, z) of each bubble size, and Fig. 5 is a conceptual diagram of the bubbles in the Y-axis direction. A graph showing the relationship between the diameter y and the density D of the foam of the present invention, Figure 6, shows the relationship between the elongation at break Ex in the X-axis direction and Z
A graph showing the relationship with the axial elongation at break Ez,
Figure 7 shows the X
Ratio of elongation at break Ex in the axial direction Ex/Ey and elongation at break Ez in the Z-axis direction to elongation at break Ey in the Y-axis direction
Graph showing the relationship between the ratio Ez/Ey, FIG. 8 is a principle diagram of a device that presses a foam in the uniaxial direction, which consists of a pair of upper and lower rolls, and FIG. 9 is a graph showing the relationship between the ratio Ez/Ey. Figure 10 shows the principle of the device used to press the foam in the uniaxial direction, which consists of a pair of upper and lower belts and a pair of front and rear belts. A graph showing the relationship between the bubble shape y/x and the water vapor permeability Py of the final foam (Ex, Ez are 20% and 16%, respectively),
Figure 11 shows the press processing after foam molding of the material foam (elongation Ex and Ez are 20% and 16%, respectively, product thickness 25%).
mm) Graph showing the relationship between the number of days elapsed and the water vapor permeability Py of the obtained foam, 12th
The figure shows the elapsed elongation rate in the X-axis direction Ex (mechanical compression rate is 37% on both the X-axis and Z-axis x 1 time) for the same number of days until the pressing process of the foam material and the thickness of the foam. A graph divided into 25mm and 100mm, Figure 13 is a graph showing the thickness of the foam material before pressing and the amount of thickness reduction due to processing in relation to the processing equipment, △ mark is a manufacturing example of the equipment in Figure 8, ○ mark Figure 9 shows an example of manufacturing the equipment, and Figure 14 is a graph showing the relationship between the pressing distance of the processing equipment shown in Figure 9 and the variation (standard deviation) of the X-direction elongation at break of the resulting foam. Compression rate: 20%, elongation at break in the X-axis direction ≒ 20%, elongation at break in the Z-axis direction ≒ 16%), Figure 15 shows foaming between the sandwiching belts on the outlet side using the device shown in Figure 12. Graph showing the relationship between the compression and fixation time of the body and the fracture elongation Ex in the X-axis direction of the obtained foam (mechanical compression ratio =
37%, elongation rate in Z-axis direction Ez = 20-28%), 16th
The figure is a graph showing the variation in the Z-axis fracture elongation Ez depending on the pressing order (X-axis first or second) using the apparatus in Figure 9. Figure 17 is a graph showing the variation in the elongation at break Ez in the Z-axis direction using the extrusion molding apparatus. A conceptual diagram showing the dimensional relationship between the shape of the original plate of the body and the shape after cutting and finishing the heterogeneous layer including the epidermis. Figures 18 to 21 show the sampling positions and dimensions for evaluating the performance of the foam. In the figure, Figure 18 is for density and compressive strength, Figure 19 is for density and compressive strength.
The figures are for bubble diameters x, y, and z; Figure 20 is for tensile strength, elongation at break, and their variation; Figure 21 is for thermal conductivity and changes in thermal conductivity over time; Figure 22 is a principle diagram of the device for accelerated moisture absorption to evaluate the temporal change characteristics of thermal conductivity, Figure 23 is for measuring water vapor permeability Py, and Figure 24 is
The figure shows the sampling position and dimensions of the panel material for evaluating the cryogenic resistance of foam.
This is a diagram showing a panel for evaluating cryogenic resistance. Figures 26 and 27 are diagrams of the principle of the device for evaluating cryogenic resistance in the panel. Figure 26 is approximately negative.
Figure 27 shows the test equipment for immersion in liquid nitrogen;
The figure shows sampling positions and dimensions for pipe cover formability evaluation and thermoforming.
Figure 0 shows the principle diagram of the pipe cover thermoforming fixing jig, Figure 31 shows an example of the construction cross section of the pipe cover cryogenic piping construction test, and Figure 32 shows the pipe cover cryogenic piping construction test equipment. FIG. 33 is a diagram showing the principle and a cross section in the longitudinal direction of the construction pipe, and FIG. 33 is a diagram showing the principle of a compression processing machine that operates in the vertical direction. 1... Inlet side upper drive roll, 2... Inlet side lower drive roll, 3... Outlet side upper drive roll, 4... Outlet side lower drive roll, 5, 6... Clamping device, 7... Unprocessed foam board, 8... Pressing Processed foam board, 9... Inlet side upper belt type clamping body, 10... Inlet side lower belt type clamping body, 11... Outlet side upper belt type clamping body, 12...
Outlet side lower belt type clamping body, 13, 14... clamping pressure device, 15, 16, 17, 18; auxiliary roll group, 1
9, 20, 21, 22; Clamping belt, 23... Unprocessed foam board, 24... Pressed foam board, 25... Heat insulating material, 26... Container, 27... Temperature controller, 28...
Water, 29...Test piece, 30...Patzkin, 31,3
2; Circulating water outlet, inlet, 33...Cooling plate, 34...Cryogenic resistance test panel, 35...Test foam, 36...
Urethane cryogenic adhesive layer, 37, 38; plywood, 39... cryogenic tank, 40... liquid nitrogen cylinder, 4
1...Liquid nitrogen piping, 42...Flow rate automatic control valve, 43
...Liquid nitrogen jet nozzle, 44...Perforated jammer plate, 4
5...Thermometer, 46...Nitrogen gas outlet, 47...Insulating material, 48...Liquid nitrogen immersion test device, 49...Deep tray, 50...Liquid nitrogen, 51...Liquid nitrogen introduction valve,
52... Iron weight, 53... Test piece for pipe cover workability evaluation, 54... Stainless steel 304 pipe, 55
... Galvanized iron plate, 56 ... Pressed and bent test foam,
57... Iron band for tensioning, 58, 59... Gap between forming pipe and formed body, 60... Pipe construction cross-sectional structure, 61, 62... 1/2 arc formed pipe cover for first layer, 63... Length direction joint Department, 64, 65...
1/2 arc molded pipe cover for second layer, 66... Moisture barrier layer, 67... Cryogenic practical piping test device, 68... Liquid nitrogen discharge valve, 69... Circumferential joint part, 70... Partition flange, 71... Pipe cover and adhesive layer of partition flange part, 72...50 ton press machine, 73... Formwork, 74... Pressing part, 75... Board-shaped foamed styrene resin molded product made of beads, 76... Top press plate, 77
...Bottom press plate.

Claims (1)

[Scope of Claims] 1. A rectangular parallelepiped-like foam having a closed cell structure with wrinkles on the cell walls, each of which is measured along three axes (X, Y, and Z axes) perpendicular to each other. The average cell diameter (x, y, z) [mm] is the foam density (D) [Kg/
m ³ ] (approximately 20 to 100Kg/m ³ ), 0.05y1.0
[mm], y/x1.05, y/z1.05 satisfies the relationship (-75log y+55)D(-5log y+20), and the water vapor permeability in the Y-axis direction Py[g/
^m2・hr] satisfies a value of 1.5 or less, and when this foam is further stretched in the X, Y, and Z axis directions,
Between the elongation at break Ex, Ey, and Zy [%] in each direction, in the range of 60Ex8 and 60Ez8, (8Ex-56) Ez (1/8 Ex + 7) and (90- Ex) Ez, where 8.3>Ex/Ey>1.8 , 8.3>Ez/Ey>1.8 and Ex+Ey<12Ey.