JPS5920655A - Composite board for low-temperature heat insulation - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite plate for low-temperature insulation suitable for insulation of a car. The purpose is to propose a low-temperature, heat-insulating composite board that does not develop cracks or expand the joint space even at extremely low temperatures, has high stability in size and shape, and can be attached to curved surfaces.

Conventionally, a composite board in which plywood or the like is laminated on a hard polyurethane foam has been used as a low-temperature insulation U. However, -1
When the temperature reaches an extremely low temperature of 00°C or lower, the foam shrinks and cracks occur along the grain of the plywood, which induces cracks in the internal foam, resulting in a reduction in heat insulation. In addition, in order to prevent this drawback, a proposal was made to interpose a fiber layer between the foam and the plywood to prevent cracks in the plywood (1983-1998).
110925) is also available. However, even with this method, the absorption of shrinkage stress within the foam is insufficient and it is not possible to completely prevent cracks from occurring within the foam. In addition, it is difficult to form a curved surface of a composite board made by laminating plywood, and there is a drawback that it is not possible to form a heat-insulating surface in a spherical or cylindrical shape.

This invention was made by focusing on the above-mentioned problems.
The gist of this is that a thin layer is integrally laminated on at least one surface of a hard synthetic resin foam via an adhesive, and the foam has a density of 65 to i00 Kf/m' in the thickness direction. When the Y-axis, width, and length directions are the X and Z axes, the water vapor permeability in the Y-axis direction PV≦1.5 [11An” -hr], X
The elongation at break in the axial and Y-axis directions EZ, Ey is 60≧
This is a composite plate for low-temperature heat insulation provided with a foam layer satisfying Era≧8.6o≧El≧8 (H).

This composite board uses a hard synthetic resin foam as a heat insulating layer, but a high elongation foam layer with an elongation of 8 to 60% in the width and length directions is used as a laminated board at extremely low temperatures. However, the shrinkage stress is absorbed and relaxed within the high elongation foam layer and no cracks occur.
The shrinkage is restricted by the shrinkage ability of the laminated thin layer bodies and is reduced, approaching the coefficient of linear expansion of the body to be insulated, so that the laid C-joints are difficult to open and a heat insulating layer without defects can be formed. If a reactive synthetic resin (for example, a urethane-based two-component adhesive) is applied to a foam as a thin layer and molded and cured under pressure or clamping, it can be applied to curved surfaces such as cylindrical and spherical shapes. It can be molded, and in addition to the rigidity of the cured synthetic resin layer, it also has excellent shape retention, making it easy and reliable to insulate curved surfaces.

At the same time, it is lightweight, has high compressive strength, has excellent installation workability, has high creep resistance, and can withstand long-term high loads, so it is particularly suitable for forming heat insulating layers on large areas such as the bottom and side walls of LNG tanks. .

This composite plate will be explained below using the drawings.

In FIG. 1, a thin layer 2 is laminated and integrated on one surface of a hard synthetic resin foam 1 made of polystyrene (hereinafter simply referred to as foam) via an adhesive 3, and a composite board 4 for low-temperature insulation (
(hereinafter simply referred to as a composite board) is constructed.

In FIG. 2, a composite plate 4 is constructed by laminating thin layers 2.2 on both surfaces of a foam 1 via adhesives 3, 3.

The foam 1 constituting these two composite plates 4 has a density of 65~
100 to 9/m", the thickness direction is the Y-axis direction, and the elongation at break in the X- and Z-axis directions perpendicular to this is Ee, Ex
must be in the range of 896 to 60 cm, respectively, and the water vapor permeability in the Y-axis direction py≦1.51 J/m”・hr].If the density is less than 35 Km/m°, it must be used for low-temperature insulation. Sufficient compression resistance.

It is only possible to provide creep resistance, thermal insulation properties, and moisture permeation resistance. If it is 100 Ky/m or more, the rigidity is high (l), and it becomes difficult to set Ez and Eg to 8% or more.

From the viewpoint of compression resistance, it is preferable that the density be 4 to 6 or more.

The water vapor permeability PV will be 1.5 or less.If maintaining long-term heat insulation performance is important, it is more preferable that py be 1.0 or less. Elongation rate E2+.

Eg is 8-6096. If it is less than 8 ots, absorption and relaxation of shrinkage force at low temperatures is insufficient, and if it is 6 ots or more, water vapor permeability and mechanical performance of the foam will be greatly reduced, which is not preferable. Generally, the object of the present invention can be achieved if the elongation rate is 40% or less. As the thin layer, 5 to 20 silk plywood, a synthetic resin (0.3 to 2 m111) reinforced with a net made of glass IIA fiber or synthetic fiber, etc. can be used, and the material is selected depending on the purpose. Polyurethane-based adhesives for foam and plywood have excellent adhesive strength and low-temperature properties.

Epoxy or the like is used, and the synthetic resin layer is preferably one that has adhesive strength with the above-mentioned foams.

This composite plate has the above-mentioned structure, and the composite plate 4 shown in Fig. 1 can be attached to a low-temperature object to which the foam 1 is to be insulated, or the composite plate 4 shown in Fig. 2 can be attached to a thin layer 2 on one side of the low-temperature object. It is attached and insulated. A temperature gradient occurs in the composite plate, with the low temperature on the cold object side and the outside air temperature on the opposite side. Therefore, a shrinkage difference occurs between the low temperature side and the high temperature side, and strain stress acts on one layer of the foam.
This strain stress is absorbed and relaxed by Ex and Kg, thereby preventing the occurrence of cracks in the foam. At the same time, interfacial peeling with the thin layer does not occur.

A fiber-reinforced resin or the like is used for the thin layer body 2 of this composite plate. For example, since the foam has a high elongation rate in the X-axis and Z-axis valves, the composite plate shown in Figs.
As shown in the figure, a curved surface with an arcuate cross section can be used to form a heat insulating surface for a cylindrical tank, etc., and as shown in FIG.

FIG. 6 shows a structure having a reinforcing laminate 2 on one side and a foam layer on the first side.
As shown in the figure, if the insulation performance is insufficient with one layer, multiple layers (
This figure shows an embodiment in which the foam layer lα, 1b) is used. Depending on the temperature of the object to be insulated, the performance of the insulation material, and the required insulation conditions, a thick insulation layer can be formed by laminating and integrating the foam layers with an adhesive. The adhesive is preferably a urethane-based or epoxy-based adhesive that has excellent low-temperature properties. If necessary, a mesh such as glass M fiber may be inserted between each foam layer to reinforce the adhesive layer.

The hard synthetic resin foam used in the present invention refers to polystyrene,
Methyl methacrylate6. A foam made from a hard synthetic resin such as vinyl chloride.

In particular, when compressive strength and long-term compression creep resistance are required of the foam itself, it is more beneficial to use a foam made by using a styrene resin and foaming it by a known extrusion foaming method.

The polystyrene that makes up the extruded polystyrene foam is
Although the resin contains styrene as a product, other styrenic monomers such as α-methylstyrene, vinyltoluene, and ruby styrene may be used instead of styrene.

In addition, a monomer copolymerizable with the above styrenic monomer,
Examples include copolymers of acrylonitrile, methacrylonitrile, methyl acrylate, methyl methacrylate, maleic anhydride, acrylamide, vinylpyridine, acrylic acid, methacrylic acid, and the like.

Furthermore, the following may be used by blending other polymers with the above-mentioned styrenic polymer to the extent that its properties are not impaired.

Polystyrene extruded foam whose main component is styrene is
Rich in closed cells, insulation and moisture permeation resistance.

Although it has excellent compressive strength, long-term compression creep resistance, and low water vapor permeability, the elongation at break is generally 5% or less. Eg
Unless it is given an elongation of 8 to 60 inches in the force direction, it is difficult to absorb thermal stress at extremely low temperatures or to form it into a cylindrical or spherical shape.

The heat insulating board for the composite board of the present invention can be achieved by compressing it in the X axis (Changminfang rotation) and the Z axis (rlj direction) as described below.

As shown in FIG. 7, a drive speed difference is provided between the two pairs of clamp drive belts 6, 7 and 8, 9, and the foam 10 is fed between them. Compression processing is performed in the transport direction, for example, in the X-axis direction.

Elongation of p18 to 60q6 can be imparted depending on the drive speed difference and the number of processing. Similarly, the foam is compressed in two axial directions to obtain a foam with high elongation.

This elongation makes it possible to absorb thermal strain generated in the foam layer at low temperatures and to suppress molding into a cylindrical or spherical shape along the shape of the object to be insulated.

Processing means for using this composite plate (FIGS. 1 and 2) as a cylindrical or spherical composite plate will be described below.

The thin layer is selected from a reactive synthetic resin that has excellent adhesion to the foam and excellent mechanical properties at low temperatures, reinforced with glass fiber mesh.

A urethane-based two-component adhesive is applied to the entire surface of the foam (example of conditions; polystyrene type) that has been subjected to compression processing using the apparatus shown in Figure 7. Next, a reinforcing layer is placed, and the same adhesive is applied over it. The reinforcing layer is filled with the reinforcing layer, and while the reinforcing adhesive layer is uncured, the composite board is pressed or clamped onto a cylindrical or spherical mold surface having a curvature similar to that of the heat-insulating body, and heated at preferably 60 to 90°C. After curing the synthetic resin under heating conditions of 70° C. to 80° C., it is cooled and demolded.

Depending on the curing conditions of the synthetic resin layer, this can be performed cold to form a curved surface. However, heating at 60 to 90° C. is more suitable because the curing time is shorter and the bending strain of the foam is completely relaxed.

The measurement method and evaluation of each characteristic in the present invention were carried out as follows.

(1) Density: (Kt/m") A cube of 5 an x 5 cm x 5 cm was taken from the foam, and one volume of one cube was determined from 1, and the average value of the five pieces was calculated as the density (Kf/m"). ”).

(2) Compressive strength: ("t/etA) The compressive strength was measured based on ASTM D1621 in the thickness direction (Y-axis direction) of the 5 crn x 5 cm x 5 cm test piece whose density was measured. Expressed as an average value.

The compression strain rate is 5%. However, if a yield phenomenon occurs within 5 inches, the yield value is taken as the compressive strength and evaluated according to the following criteria.

(3) Elongation at break (a) Tensile strength measurement method, based on ASTM 01625 B method, tensile the test piece in the specified directions (X and 2), and measure the amount of strain (elongation! bumps) when it breaks. Calculate and evaluate using the following formula.

Collect 1-5 test pieces in each direction.

Test piece; 50 m x 50 srr x 50 m
(4) Water vapor transmission rate * WVT R (1/m”・h
r) Take 6 test pieces of 25111 x 80φ, and
Measure according to STMC355. W at 25mm thickness
VTR is calculated using the following formula. However, it is carried out using a method using distilled water.

WvTR (1/rn" ・hr) = - -t a: Xik change concavity t: tt
it (m”) (5) Rate of change in thermal conductivity over time As shown in Figure 8, the suppressed product is
51+1. A test piece with a length of 200 fl is taken during the middle 200 minutes and measured using the apparatus shown in FIG.

A container 11 equipped with a temperature vM moderator 13 surrounded by a heat insulating material 12
Water 14 at 27° C. is poured into the container, and the opening side of the container is sealed with the sample piece 15 described above. At this time, the distance between the bottom surface of the sample piece and the water surface in the container is approximately 3
Arrange them so that there is a distance of 0. In addition, test piece 15
The upper surface of the cooling plate 19 is in close contact with a cooling plate 19 which is cooled to 2° C. by cooling water circulated from circulating water ports 17 and 18. After leaving this condition for 14 days, wipe the surface of the sample piece with gauze and clean it according to ASTM C51.
Measure the thermal conductivity λ' of this material according to 8, calculate the rate of change λ'/λ from the thermal conductivity λ measured under the same conditions before the test, and evaluate it according to the following table (6). A test plate with cryogenic resistance of 5011 m1 x 300111 x 3001111 was taken, and after cutting and finishing the top and bottom surfaces, the X-axis was cut as shown in Figure 10.

12 seaweeds x 3 on the upper and lower surfaces of the test foam 21 with the z-axis direction clearly specified
Glue 00 silk x 300 fin plywood (JAS standard product) 23° 24 with polyurethane two-component cryogenic adhesive (manufactured by Sumitomo Bakelite Co., Ltd.: Sumitaku EA90177) 22.
It was aged and hardened under a pressure of 0.5 Kfi shoulder at 23° C. to prepare test nonel 20, and six pieces were manufactured and tested.

1) Cryogenic knee 160°C test As shown in FIG.
It is rapidly placed into a cryogenic chamber 25 whose internal temperature is controlled to ±5°C, and after being left for 5 hours, it is quickly taken out to room temperature and left to stand for 1 hour. This operation is repeated 4 times, and the cryogenic chamber 25 is heated for the fourth time.
Immediately after removing the test panel 20 from the test foam board 21, the four sides of the test foam board 21 are observed to confirm the presence or absence of cracks and the direction in which they have occurred. After 1 hour, a slice sample was sliced along the interface between the plywood boards 23 and 24 and the test foam board 21 using a single-tooth slicer, and was further divided into 5 slices with a thickness of about 10*lI inside the test foam board 21. Then, apply water mixed with a surfactant and coloring ink to the surface of each slice sample, and record the presence or absence and direction of cracks on the sample surface.

In addition, extremely low temperature 4V! The temperature inside the tank 25 is controlled by guiding the gas from the liquid nitrogen cylinder 26 through the liquid nitrogen distribution pipe 27 to the jet nozzle 29 at the top of the tank, where it is vaporized while coming into contact with the perforated baffle plate 30, and the gas is discharged from the exhaust port 32. to lower the temperature inside the tank. The cumulative flow rate of the liquid nitrogen is adjusted by opening and closing the flow rate intransitive clause by a control device that interlocks the temperature resistance 31 in the tank and a timer.

2) Cryogenic knee 196°C test W112 As shown in Figure 112, the above test panel 20 is sealed with a heat insulating material 33 and then tested in a liquid nitrogen immersion device [34].

After introducing liquid nitrogen 236 directly from the liquid nitrogen cylinder into the stainless steel deep-bottom tray 35 via the liquid nitrogen piping 27 and liquid nitrogen introduction valve 37, the test panel 20 is rapidly and sufficiently immersed in the liquid nitrogen 36. Place the iron weight 3, which has been cooled in liquid nitrogen in advance, on the iron sabot 39.
8, and after continuous immersion for 30 minutes, the above test panel 2
0 into an atmosphere and leave it for 1 hour with ventilation. 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 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.

(7) Creep resistance test Eight test pieces of 50ynx50*mx50tm were taken from the foam. Select 5 from among them and
Compressive strength t-axis) is measured in accordance with AsTM D 1621, and the average compressive strength (Kv/CI/l) is determined and calculated as σ
, and so on. The remaining three specimens were used as test specimens 45 for creep measurement, and as shown in FIG. 16, plywood sheets 41 and 42 with a thickness of 5mm were bonded and cured by pressure on the upper and lower surfaces in the thickness direction via adhesives 43 and 44. Let it be a clique performance IJ regular complex 40. Creep 1fflJ regular test bar 45 thickness direction (Y
The thickness of the shaft (shaft) is accurately measured to the unit of 17100111, and this dimension is defined as TO.

As shown in FIG. 14, the clean measurement complex 40 is gently set between the weight mount 48 of the creep measurement device 46 and the device mount 50, and then the average compressive strength C is 1 as determined by the /3 value 'V3; Weight fiV/l (W2e = 25 x'c
AWl) gently to avoid shock. Immediately after loading, the scale of the dial gauge 47 is set to zero.

23'Cx Evening degree after 1000 hours ear gauge 4
7 scale T1, that is, the amount of creep for 1000 hours (al
1) is read in units of 1/100 ml, the creep amount (chi) is determined according to the following formula, and the creep resistance is evaluated using the following criteria.

Creep amount (%) = -1-・100 T.

Example, comparative product 1 Density is 35-1ooKt/77L's Thickness 100111
A polystyrene extruded foam board (manufactured by Asahi Dow Shisha Co., Ltd.; Styro Ohm Co., Ltd.) and a polyvinyl chloride foam board were first subjected to
Suppression processing was carried out in the axial direction (length direction) and then in the Z-axis direction (width direction). At this time, only the compression ratio and number of caroes were selected as appropriate among the suppression processing conditions shown in Table 3, and the other conditions were the same. (Experiments 1 to 14).
) For comparison, extruded polystyrene foam boards with densities of 28 to 100 K17 m'' (manufactured by Asahi Dow ■; Styro Ohm ■) and unprocessed polyvinyl chloride foam boards and those processed only in the X-axis direction were used. I also made a machined version of the X and Z axis valves.

For each foam, the elongation at break in the density
), the results were evaluated using the methods and criteria described in the text, and Table 11 shows the results of each and the comprehensive evaluation of the results. The criteria for comprehensive evaluation were as follows.

◎: All characteristics are marked with ○ (satisfying the highest standards) ○: There are Δ marks, but many O marks (satisfying the purpose of the present invention) ×: Those with at least one × mark ( According to the results in Table 181, low-temperature insulation foams for LNG tanks, etc. are hard synthetic resin foams with a density of 35 to 100 Kr.
/7FL', X axis, biaxial direction (DME breaking elongation rate is 8 to 6
0%, water vapor transmission rate in Y-axis direction is 1.5#/m@・h
It can be seen that it must be less than or equal to r.

Example, Comparative Example 2 This comparison was conducted from the viewpoint of investigating the characteristics that should be provided for the insulation material inside an LNG underground tank, for example, in applications where high loads are applied for a long period of time at extremely low temperatures. This is an example. That is, an extruded polystyrene foam board with a density of 35 to 100 Kf/ma, a cell size of 0.6 to 0.11111, and a thickness of 100 mm (manufactured by Asahi Dow ■; Stylofono ■)
was first compressed in the X-axis direction (length direction) and then in the Z-axis direction (width direction) using the suppression device shown in FIG. 7 according to the manufacturing method described in the text. At this time, only the medium compression ratio and the number of processing times of the suppression processing conditions shown in Table IJc3 were selected as appropriate, and the other conditions were the same, and the density and compressive strength were determined.

Materials were created to evaluate elongation at break, water vapor permeability, rate of change in thermal conductivity over time, panel cryogenic resistance, creep resistance, etc. (Experiment Na15-28) For comparison, unprocessed extruded polystyrene foam boards (Asahi Dow ■; Styro Ohm ■) with a density and degree of 28 to 100 Ktt/m" and those processed only in the Xll11 direction, We also manufactured products processed into X- and Z-axis valves.For comparison of foam materials, commercially available polystyrene bead foam boards, polyvinyl chloride extrusion foam boards, and molded boards (thickness: 2Q) were also manufactured.
m) Polymethyl methacrylic acid extruded foam board (Asahi Dow prototype; thickness 20u) with and without processing and general-purpose rigid polyurethane (N1147) Semi-rigid polyurethane formulated as LNG underground tank insulation material (straight 48 mm) ~50) were added to serve as evaluation materials.

Using the methods described in the text, we measured the density, water vapor permeability, and thermal conductivity over time in the X-axis and Z-axis directions, as well as the gallery strength and durability in the Y-axis direction, for each foam. Focusing on creep property and cryogenic resistance (<-1<50°C and -196°C), evaluations were made using the methods and criteria described in the text, and the results for each and the comprehensive evaluation are shown in Table 2. . The criteria for comprehensive evaluation are as follows: IF:.

◎: All °C characteristics are marked with ○ (satisfied with the highest standards) 0: There are Δ marks but many Q marks (satisfies the purpose of the present invention) ×; There is at least one × mark According to the results in Table 2, the foam that satisfies the purpose of being used as an internal insulation material for tanks such as LNG according to the present invention is extruded polystyrene foam with a density of 35 to 100 (Kf). /m'),
It can be seen that the elongation at break in the X-axis and z@ directions must be 8 to 60 inches, and the water vapor permeability in the Y-axis direction must be 1.5 (17 m-5 r) or less.

Furthermore, the function as a heat insulating material for LNG underground tanks is improved, and -
The foam of the present invention, which is considered as a cold insulator for liquid nitrogen at 196°C and has other properties at the highest level, has a density of 40 to 100.
(Kf/rIL'), the elongation at break Ez and Eg in the X-axis and z-axis directions must be 12 to 40 inches, and the water vapor permeability in the Y-axis direction must be 1.0 [117 m-r] or less. I understand.

ts6 surface machining conditions Aging days until machining: 1 day Processing thickness: 100jl11 Machining speed (entrance belt): 12 m/By (3
Compression ratio (inlet/outlet belt speed ratio): 1.05~1
．． 33 Suppression distance (person, distance between exit belt axes): 200m
Suppression fixing time = 6.6 seconds Machining times l11. :1 to 3 times

[Brief explanation of drawings]

1 and 2 are sectional views of the composite plate according to the present invention, and FIGS. 3 and 4 are perspective views of the composite plate of FIGS. 1 and 2 bent into a cylindrical shape, respectively, Figure 5 is the first
FIG. 6 is a perspective view of the composite plate shown in the figure after being bent into a spherical shape. FIG. 6 shows an embodiment in which the composite plate shown in FIG. Cross-sectional view, Figure 7 is a schematic diagram showing the state in which the foam is compressed and given a high elongation rate, Figure #I8 is a diagram showing the sampling position and dimensions for measuring the rate of change in thermal conductivity over time, Figure #J9 is a diagram of the principle of the device for accelerated moisture absorption for evaluating the temporal change characteristics of thermal conductivity, Figure 10 is a diagram showing a panel for evaluating cryogenic resistance, and Figures 11 and 12 are diagrams of the panel. This is a principle diagram of the equipment for evaluating cryogenic resistance.
Figure 2 is a schematic diagram showing a test device immersed in liquid nitrogen, Figure 16 is a diagram showing a complex for measuring the amount of creep,
FIG. 14 is a schematic diagram showing a creep measuring device. l...foam, 2...thin layer, 3...
...Adhesive, 4.4'...Composite board, 5...
...Reinforcement fiber #&layer, 6,7゜8.9...Pinch drive belt, IO...Foam, 11...
...Container, 12...Insulation material, 13...
Temperature regulator, 14...Water, 15...Test piece, 16...Packing, 17° work 8...
...Circulating water inlet/outlet, 19...Cooling plate, 20...
...Cryogenic temperature, resistance test panel, 21...
Test foam, 22... Urethane cryogenic adhesive, 23, 24... Plywood, 25...
Cryogenic chamber, 26...Liquid nitrogen cylinder, 27...
...Liquid nitrogen piping, 28...Liquid nitrogen flow rate automatic control valve, 29...Liquid nitrogen jet nozzle, 3
0...Perforated jammer plate, 31...Temperature 1
t, 32...Nitrogen gas discharge port, 33...
・Insulating material, 34...Liquid nitrogen immersion test device, 3
5...Deep tray, 36...Liquid nitrogen, 37...Liquid nitrogen introduction valve, 38...
Iron weight, 39... Iron support, 40...
... Creep measurement complex, 41, 42...
・Plywood, 43, 44...Adhesive, 45...
...Test piece for creep measurement, 46...Creep measuring device, 47...Dial gauge, 48...
... Weight mount, 49 ... Weight, 50 ...
・Creep measuring device R mount. Figure 1 Figure 5 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 2 Day 12 Figure 13 Figure n Figure 14

Claims (1)

[Claims] (1) A thin layer is integrally laminated on at least one surface of a hard synthetic resin foam with an adhesive, and the foam has a density of 65 to 100 Kt/m. Thickness direction is Y
Axis, 'l'? When the length direction is the X and Z axes, the water vapor permeability in the Y-axis direction py≦1.5 [1m”・Ar), X-axis, 2
Axial elongation at break Ex. A composite board for low-temperature insulation, characterized in that Eg is 60≧Eπ≧8.60≧Eg≧8 (a hook foam layer is provided).