JP2000110988A - Insulation structure - Google Patents

Abstract

(57) [Problem] To provide a heat insulating structure using a novel convection preventing material for low-temperature heat insulation as a joint material for joints. SOLUTION: A low-temperature heat insulating convection preventive material 4 made of a lightweight organic foam made mainly by reacting an organic polyol and an isocyanate component is compression-deformed and inserted into a joint portion of a molded heat insulating material 2 covering a pipe 1 by compressively deforming the same. I do. The convection preventive material for low-temperature insulation is capable of forcibly restoring by 60% in the normal temperature to low temperature range (50 to -240 ° C.), and exhibits gas barrier properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to LPG, LNG,
The present invention relates to an improvement of a heat insulating structure suitable for heat-insulating transport pipes and storage tanks handling cryogenic liquid flows such as LEG.

[0002]

2. Description of the Related Art Conventionally, in such a heat insulating structure, glass wool or rigid urethane foam has been mainly used as a filler for a joint material. Glass wool has excellent flexibility, and rigid urethane foam has excellent gas barrier properties, and is used as a joint material for heat insulation according to each application.

[0003]

Although the glass wool has excellent flexibility, it is a fiber and does not have a gas barrier property, and has high heat transfer by convection because of gas permeation. However, glass wool is used in joints and fillers that follow the displacement of joints and fillers due to shrinkage deformation of the heat insulating structure, and where flexibility is required, which is a property that prevents the occurrence of gaps. . In such a case, a seal is required at a portion where gas barrier properties are required, and the construction for the seal must be performed separately, which inevitably increases the cost.

[0004] On the other hand, rigid urethane foam is generally subjected to in-situ injection foaming and exhibits excellent gas barrier properties and low thermal conductivity, but is inflexible and requires a flexibility. Can not be used as jointing material and filler. Although there is a flexible urethane foam made of a similar material, it is hardly used at low temperatures because it hardens at a low temperature and has voids (bubbles) because it is an open cell. Generally, LPG (−80 ° C.), LNG (−162
℃), and there is no joint material having gas barrier properties while maintaining flexibility.

[0005] Therefore, there is no structure incorporating the joint material and the filler which satisfy both the flexibility to the joint portion and the filling portion and the gas barrier property in the heat insulating structure. Are being selected. For this reason, there is a problem of cost increase in design and construction. The present invention relates to a heat insulating structure using a novel low-temperature heat insulating convection preventive material made of a lightweight organic foam having both the flexibility at low temperatures of glass wool and the gas barrier properties of rigid urethane foam as a joint material and a filler. Its primary purpose is to provide.

[0006]

SUMMARY OF THE INVENTION A heat insulating structure according to the present invention is characterized in that a convection preventing material for low-temperature heat insulation is compression-deformed and inserted into joints and filling portions of the heat insulating structure. . The convection preventing material for low-temperature insulation used in the present invention is obtained by reacting an organic polyol, water, a nonionic surfactant, a flame retardant and a mixture of inorganic and organic compounds with a polyisocyanate in the presence of an imidazole compound. It is a structured lightweight organic foam.

Examples of the organic polyol include polyether polyols having propylene glycol, ethylene glycol, glycerin, triol, triethanolamine and the like as initiators, adipic acid, phthalic acid, dimerized linoleic acid, maleic acid, glutaric acid and the like. Polyester polyol or polycaprolactone polyol and the like as an acid component, each glycol such as ethylene, propylene, butylene, hexane, methylene, neopentyl and the like, and trimethylolpropane, hexanetriol, glycerin, pentaerythritol and the like as a polyhydroxy compound. You.

The imidazole compound as a catalyst includes imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1,2,4-trimethylimidazole, 1,2,5-trimethylimidazole, 2,4,5 -Trimethylimidazole and the like.

[0009] The nonionic surfactant is used as an emulsifying dispersant, and includes polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol, fatty acid ester, glycerin fatty acid. It is desirable to use esters, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, alkylalkanols, amides and the like.

As the flame retardant, tris (2-chloroethyl) phosphate, tris (chloropropyl) phosphate, tris (2,3-dichloropropyl) phosphate, (2,3-dibromopropyl) phosphate, tetrakis ( 2-chloroethyl) Phosphorus / halogen compounds such as ethylene diphosphate, organic phosphorus compounds such as trisyl phosphate and dimethyl phosphate, phosphorus-free aliphatic halogen compounds such as paraffin chloride, brominated diphenyl oxide and the like. Alicyclic or aromatic halogen compounds;

Further, the polyisocyanate is a known aromatic, araliphatic, aliphatic or alicyclic polyisocyanate conventionally used in the production of urethane foam, or a modified product thereof. For example, diphenylmethane diisocyanate, tolylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, isophoroanate, polymethylene polyphenyl polyisocyanate, hydrogenated tolylene isocyanate and the like. The convection preventing material for low-temperature insulation made of the lightweight organic foam having the above-described structure,
Density 5 to 40 kg / m ³ , thermal conductivity 0.03 to 0.05
W / m · K and normal to low temperature range (50 to -240 ° C)
Is characterized by being capable of forcibly compressive restoration deformation of 60% and exhibiting gas barrier properties, and is a material having properties different from general soft urethane foam. For example, JF foam (Nichias Corporation) has been commercialized.

Here, the operation and effect of the heat insulating structure in which the convection preventing material for low temperature heat insulation made of the lightweight organic foam is inserted into the joint portion and the filling portion will be described below. As described above, the low-temperature heat-insulating structure is generally used for heat insulation in a low-temperature region such as a tank or a pipeline of liquefied natural gas, liquefied propane gas, liquid nitrogen, or liquid hydrogen. It is a molded rigid urethane foam with low thermal conductivity. Then, the molded rigid urethane foam is processed and manufactured into the shape of a board or a cover, and attached around a low-temperature portion such as a tank or a pipeline to prevent heat from entering from the outside. Since the molded rigid urethane foam, which is the main material of the low-temperature insulation structure, is a set of a plurality of molded bodies having a shape such as a board or a cover, a joint is formed between the molded bodies.
Glass wool and rigid urethane foam (injection) exhibiting low-temperature insulation properties at the joints that are joints or filled parts
Is used.

In general, the volume of a material changes due to a change in temperature. Depending on the type, for example, when the molded rigid urethane foam has a linear shrinkage of 5 × 10 ⁻⁵ per 1 ° C., the temperature of the material is changed from 20 ° C. to −160 ° C. to obtain 9 × 10 ⁻³ . Shows the linear shrinkage. For a rigid urethane foam having a length of 1 m, the occurrence of shrinkage of 9 mm in the length direction is calculated.

The joint width between the rigid urethane foams is 10
mm, when the molded rigid urethane foam shrinks by 9 mm, the joint width becomes 19 mm. If the joint has been subjected to in-situ injection foaming of rigid urethane foam as a joint material, shrinkage is designed to be suppressed by the strength of the joint material. However, when the design is made in consideration of the relaxation of the stress due to the contraction of the rigid urethane foam, a problem occurs.

When glass wool is used as the joint material, the joint width increases from 9 mm to 19 mm, and a gap is formed between the filled glass wool and the molded rigid urethane foam, or the glass wool is bonded to the molded rigid urethane foam. If so, the density of the glass wool will be low. Therefore, the amount of voids at the joints increases, and convection of air is likely to occur.

However, as an alternative to rigid urethane foam (injection) or glass wool, the convection preventing material for low-temperature insulation, which has both flexibility and convection preventing performance, is compressed and deformed in a range of up to 60%, and is applied to joints and filling portions. By inserting, the joint width is 9mm to 19m in the previous example.
m can be accommodated. That is, the construction by compressive deformation in anticipation of the expansion displacement of the joint width absorbs the expansion displacement of the joint width, and also exhibits the gas barrier property. By using as a preventive material, it is possible to release strain stress due to a temperature change of the heat insulating structure and to provide excellent heat insulating properties.

When compressing the convection-preventing material for low-temperature insulation to the heat-insulating structure, it is necessary to take into consideration the amount of displacement of joints caused by temperature change of the heat-insulating structure. When the shrinkage is small and the displacement of the joint is small, and when the elongation of the convection prevention material for low-temperature insulation is within the allowable range, it is not always necessary to compress the convection prevention material for low-temperature insulation. It is possible to cope with the deformation of the prevention material. In such a case, it is possible to inject the convection preventing material for low-temperature insulation on site.

[0018]

Embodiments of the present invention will be described below. The convection preventing material for low-temperature insulation to be inserted into the joint portion and the filling portion of the heat insulating structure includes 10 parts by weight of an organic polyol and 10 parts by weight of an isocyanate.
A reaction-produced lightweight organic foam mainly composed of 0 parts by weight, 40 parts by weight of a foaming agent, and 2 parts by weight of a catalyst was used. The properties of the foam are as follows.

Density 15 kg / m ³ Thermal conductivity 0.041 W / m · K Possible forced compressive recovery deformation (normal temperature to low temperature) 85% No gas permeation None FIG. 1 to FIG. 2 show a heat insulating structure. For comparison, another 24 kg of glass wool was used as a convection preventing material for the heat insulating structure.
/ M ³ (thermal conductivity 0.041 W / m · K).

Embodiment 1 FIG. 1 shows a heat insulating structure using a low-temperature insulating material.
In the figure, 1 is a pipe, 2 is a cover-type molded heat insulating material made of hard urethane foam, 3 is a binding material, and 4 is a convection preventing material for low temperature heat insulation. The convection prevention material 4 for low-temperature insulation is about 2 at the joint.
Insertion was performed at a compression state of 0%, and bonding was performed with a molded heat insulating material and a low-temperature adhesive. By cooling the piping,
The molded insulation 2 is cooled and the joint width is from 20 mm to 25 m
m, but the convection preventing material for low-temperature heat insulation 4 followed the deformation, and no decrease in heat insulation performance was observed. When glass wool was used in place of the convection preventing material 4 for low-temperature insulation, the joint width was followed by deformation. Leakage occurred.

Embodiment 2 FIG. 2 shows another heat insulating structure using a convection preventing material for low temperature heat insulation. In the figure, 5 is a frame, 6 is a block-shaped molded heat insulating material made of hard urethane foam, and 7 is a fixture with bolts and washers. The convection preventing material for low-temperature insulation 4 was attached to the joint in a compressed state of about 50%. Also,
The convection preventing material for low-temperature insulation 4 was processed with a molded heat-insulating material and a low-temperature adhesive. By cooling the frame, the upper surface of the formed heat insulating material was cooled, and the joint width was changed from 20 mm to 25 mm. However, the low-temperature heat insulating convection preventing material 4 followed the deformation, and no decrease in heat insulating performance was observed. When glass wool was used in place of the convection preventing material 4 for low-temperature insulation, the deformation of the joint width was followed. However, air convection occurred in the glass wool, and the lower surface of the joint part surface and the skeleton part due to deterioration of heat insulation performance. Cooling was observed.

FIGS. 3A, 3B and 3C show examples of joint structures of a heat insulating structure using a convection preventing material for low temperature heat insulation. As shown in FIG. 3A, the joints of the heat insulating structure do not need to be completely filled with the convection preventing material 4 for low-temperature heat insulation. As shown in FIG. 3 (c), the filling rate of the convection preventing material 4 for low-temperature heat insulation may be adjusted.

In the heat insulating structure of the present invention, the convection preventing material for low-temperature insulation is used as a joint material and a filler. It can be opened by deformation.
When the design conditions are special, the convection preventing material for low-temperature heat insulation itself may be used as the molded heat insulating material of the heat insulating structure.

[0024]

As described above, according to the present invention, according to the present invention, the stress caused by the temperature change of the molded heat insulating material covering the heat insulating object is released by the novel convection prevention material for low temperature heat insulation. A low-cost heat insulating structure can be provided.
In addition, the heat insulation structure according to the present invention is particularly useful as a cold insulation structure in a temperature range of −50 ° C. or lower.

[Brief description of the drawings]

FIG. 1 is a perspective view of a heat insulating structure showing one embodiment of the present invention.

FIG. 2 is a perspective view of a heat insulating structure showing another embodiment of the present invention.

FIG. 3 is an explanatory view showing an insertion example of a convection preventing material for low-temperature insulation in a heat-insulating structure according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piping 2 Molded heat insulating material 3 Tightening material 4 Convection prevention material for low-temperature heat insulation 5 Frame 6 Molded heat insulating material 7 Fixture (bolt / washer) 8 Glass wool

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H036 AA02 AB18 AB25 AC02 AE07 4F100 AK51A AK51B BA02 CA01 DC28B DJ01A DJ01B GB90 JA13A JD02A JJ01A JJ02 JK12B JL03A YY00A

Claims (4)

[Claims] 1. A heat insulating structure obtained by compressively deforming and inserting a low-temperature heat insulating convection preventing material into joints and filling portions of the heat insulating structure. 2. The convection preventing material for low-temperature insulation has a density of 5 to 5.
40 kg / m ³ , thermal conductivity 0.03-0.05 W / m
K, and 6 at room temperature and low temperature (50 to -240 ° C)
The heat insulating structure according to claim 1, wherein a light-weight organic foam which is capable of forcible compression deformation of 0% and has a gas barrier property, which is mainly obtained by reacting an organic polyol and an isocyanate component, is used. 3. The heat-insulating structure according to claim 1, wherein the low-temperature heat-insulating convection preventing material is compressed and deformed in consideration of an amount of expansion displacement at a low temperature of a joint portion and a filling portion in the heat insulating structure. 4. The heat insulating structure according to claim 1, wherein the heat insulating structure is made of rigid urethane foam.