Elastic felt for low-temperature storage tank and method for manufacturing the same

Abstract

In order to solve the problems of many production processes, low production efficiency and unstable product quality of the existing elastic felt for low-temperature storage tank, the present application provides an elastic felt for low-temperature storage tank and a preparation method thereof. The elastic felt is formed by repeatedly crossing and stacking two groups of glass fibers after spraying resin glue. The mass ratio of the glass fiber is 80-90%, and the solid mass ratio of the resin glue is 10-20%. The length of the first group of glass fibers is 20-70mm, the diameter is 3-6 microns, and the curling degree is 10-20%. The length of the glass fibers of the second group of glass fiber mats is 70-150mm, the diameter is 6-12 microns, and the curling degree is 20-30%. The preparation method is online one-time forming, has few preparation process procedures, good stability, good resilience of the prepared elastic felt, high strength, and excellent heat insulation performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of glass felt, and particularly relates to an elastic felt for low-temperature storage tanks and a preparation method thereof. BACKGROUND

[0002] Large low-temperature storage tanks are commonly used storage devices in modern industry, and are mainly used for storing low-temperature media such as LNG. The elastic felt is an important cold insulation filling material in the tank wall interlayer cold insulation system of the low-temperature storage tank. The application of the elastic felt in the field of storage tanks can directly increase the thermal resistance and reduce heat leakage. In addition, the high resilience of the elastic felt can prevent the direct contact of the expanded perlite with the inner tank, relieve the pressure of the perlite on the storage tank, and effectively compensate the space of the tank. Therefore, the resilience of the elastic felt will directly affect the cold insulation effect of the storage tank. At the same time, the elastic felt needs to be hung and laid directly from the top of the storage tank. With the increasing size of the storage tank, the maximum storage tank capacity has reached 270,000 cubic meters. Therefore, the length of the elastic felt also increases, and the tensile strength requirement of the elastic felt also increases.

[0003] Patent with publication number CN 115418790 discloses a low-density high-elasticity glass wool felt production equipment integrated system and production method, which mainly processes the glass fiber chopped strands by opening and carding. Patent CN 117107440A discloses a method for making high-temperature-resistant elastic felt, which is mainly made by continuously cutting the fibers, applying glue, laying, stacking, folding, and drying. Both patents are made from chopped strands through subsequent processing, which has low production efficiency and high production instability. Centrifugal method has the advantages of high single-machine production efficiency, good thermal insulation performance, and easy implementation of automatic production. However, the glass fiber insulation felt prepared by the centrifugal method has low strength and poor resilience. Therefore, it is of great significance to develop an elastic felt with good resilience and high tensile strength for low-temperature storage tanks, which can reduce the production cost of the elastic felt, improve the quality of the elastic felt, and promote the application of domestic elastic felt in low-temperature storage tanks. SUMMARY

[0004] To solve the problems of multiple production processes, low production efficiency, and unstable product quality of the existing elastic felt for low-temperature storage tanks, the application provides an elastic felt for low-temperature storage tanks and a preparation method thereof. The preparation method is one-step online forming, has few preparation processes, good stability, and can prepare a new type of elastic felt for low-temperature storage tanks with good resilience, high strength, and excellent thermal insulation performance.

[0005] The low-temperature storage tank elastic felt is formed by repeatedly crossing and stacking two groups of glass fibers after spraying resin glue, the mass percentage of the glass fibers is 80-90%, and the solid mass percentage of the resin glue is 10-20%; wherein the length of the first group of glass fibers is 20-70mm, the diameter is 3-6 microns, and the curling degree is 10-20%; the length of the second group of glass fiber felt is 70-150mm, the diameter is 6-12 microns, and the curling degree is 20-30%.

[0006] Optionally, the glass fibers are multiple groups, and the length, diameter and curling degree of the glass fibers are between the first group of glass fibers and the second group of glass fibers.

[0007] Optionally, the main components and contents of the glass fibers are: SiO2 55-66%, B2O3 10-19%, Na2O 8-14%, K2O 1-4%, CaO 1-5%, and Al2O3 3-12%; the resin glue is composed of 97.5-99.5% resin and 0.5-2.5% waterproof agent.

[0008] The application further provides a preparation method of the low-temperature storage tank elastic felt, which comprises the following steps:

[0009] S1, glass liquid preparation: melting raw materials of the glass liquid to obtain the glass liquid; the main components and contents of the glass liquid are: SiO2 55-66%, B2O3 10-19%, Na2O 8-14%, K2O 1-4%, CaO 1-5%, and Al2O3 3-12%;

[0010] S2, glass fiber preparation: introducing the glass liquid into respective corresponding centrifugal discs through electric heating nozzles one by one, each electric heating nozzle and the respective corresponding centrifugal disc is a group, the glass liquid is sprayed out in the form of glass filaments parallel to the horizontal plane from the small holes in the sidewall of the centrifugal disc after being heated by the electric heating nozzle; the glass filaments are vertically stretched by a 950-1250℃ flame; the stretched glass filaments are bent by hot air with an angle of 75-85° with the horizontal plane, a temperature of 300-500℃ and a pressure of 30-50KPa; the bent glass filaments are cut and cooled by high-pressure cutting air with a temperature of 5-25℃ and a pressure of 0.4-0.7MPa, to obtain two groups of glass fibers with an average length of 20-70mm and 70-150mm, an average diameter of 3-6 microns and 6-12 microns, and an average curling degree of 10%-20% and 20%-30% respectively;

[0011] S3, glue spraying: spraying resin glue on each group of glass fibers by 8-16 annular nozzles;

[0012] S4, the preparation of the elastic felt for low-temperature storage tank: two groups of sprayed resin-coated glass fibers are repeatedly crossed and uniformly attached to the collecting machine mesh belt in the adjustable air direction and air pressure negative pressure air chamber, the speed of the collecting machine mesh belt is adjusted to uniformly control the gram weight range, the curing temperature is 150-250 DEG C, the curing time is 1-3 min, and then the pressure is rolled to obtain the elastic felt for low-temperature storage tank.

[0013] Optionally, in the step S2, the first group of glass fibers is introduced into the centrifugal disc with a diameter of 300-500 mm by the glass liquid with a flow rate of 300-500 kg / h through the electric heating nozzle with a diameter of 20-40 mm and a heating temperature of 850-950 DEG C, and the centrifugal disc rotates at a speed of 1500-3000 r / min, and the hole diameter of the side wall of the centrifugal disc is 0.5-0.7 mm.

[0014] Optionally, in the step S2, the second group of glass fibers is introduced into the centrifugal disc with a diameter of 300-500 mm by the glass liquid with a flow rate of 500-800 kg / h through the electric heating nozzle with a diameter of 30-50 mm and a heating temperature of 850-950 DEG C, and the centrifugal disc rotates at a speed of 3000-5000 r / min, and the hole diameter of the side wall of the centrifugal disc is 0.8-0.9 mm.

[0015] Optionally, in the step S2, the high-pressure cutting air in the preparation method of the two groups of glass fibers is installed below the bottom of the centrifugal disc at positions of 5-10 cm and 15-20 cm, respectively.

[0016] Optionally, in the step S2, the glass fibers are multiple groups, and the length, diameter and curling degree of the glass fibers are between the first group of glass fibers and the second group of glass fibers.

[0017] Optionally, in the step S3, the resin glue is composed of 97.5-99.5% of phenolic resin aqueous solution with a concentration of 5%-15% and 0.5-2.5% of waterproof agent.

[0018] Optionally, in the step S4, the mass ratio of the glass fiber in the sprayed glue glass fiber is 80-90%, and the solid mass ratio of the resin glue is 10-20%.

[0019] The beneficial technical effects of the application are as follows:

[0020] 1. The elastic felt for low-temperature storage tank designed by the application is composed of two or more groups of glass fiber mats with different diameters, lengths and bending degrees, and has high strength, good resilience and excellent heat insulation performance.

[0021] 2、The low-temperature storage tank elastic felt preparation method designed by the application has a long glass component forming temperature range, a low upper limit crystallization temperature, and can produce long, strong, and excellent anti-aging performance glass fibers at low cost; the centrifugal forming system of the application can bend the glass fibers by adding high-temperature hot air, and can produce glass fibers with different curling degrees according to needs, so that the glass fibers have better resilience; the centrifugal forming system of the application is also designed with a cold air cutting mechanism, which can produce glass fibers with different lengths according to needs; the centrifugal forming system of the application contains two sets of different design forming equipment, which can produce glass fibers with different fiber diameters, lengths, and curling degrees at the same time, and the combination and superposition of different fibers make the low-temperature storage tank elastic felt have high stiffness, high strength, and high resilience at the same time; the low-temperature storage tank elastic felt preparation method of the application is an online one-time continuous forming method, which has fewer processing procedures, simpler process, and the characteristics of high production efficiency and stable quality. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art belong to the scope of protection of the application.

[0023] Embodiment 1

[0024] A low-temperature storage tank elastic felt is formed by repeatedly crossing and superimposing two groups of glass fibers after spraying resin glue, the mass percentage of the glass fibers is 80%, and the solid mass percentage of the resin glue is 20%; the length of the glass fibers of the first group of glass fiber mats is 20 mm, the diameter is 3 microns, and the curling degree is 10%; the length of the glass fibers of the second group of glass fiber mats is 70 mm, the diameter is 6 microns, and the curling degree is 20%. The main components and contents of the glass fibers are: SiO2 55%, B2O3 19%, Na2O 8%, K2O 4%, CaO 1%, and Al2O3 12%; the resin glue is composed of 97.5% resin and 2.5% waterproof agent.

[0025] The preparation method of the above-mentioned low-temperature storage tank elastic felt, the preparation method comprises the following steps:

[0026] S1, glass liquid preparation: melt the raw materials of the glass liquid to obtain the glass liquid; the main components and contents of the glass liquid are: SiO2 55%, B2O3 19%, Na2O 8%, K2O 4%, CaO 1%, and Al2O3 12%;

[0027] S2, glass fiber preparation: the glass liquid is introduced into the respective corresponding centrifugal disc through the electric heating nozzle respectively, each electric heating nozzle and the respective corresponding centrifugal disc is a group, the glass liquid is sprayed out from the centrifugal disc side wall small hole in the form of glass filaments parallel to the horizontal plane after being heated by the electric heating nozzle; the glass filaments after stretching are bent by hot air with an angle of 85° with the horizontal plane, a temperature of 500 ℃ and a pressure of 30 KPa; the glass filaments after bending are cut and cooled by high-pressure cutting air with a temperature of 5 ℃ and a pressure of 0.7 MPa, to obtain two groups of glass fibers with an average length of 20 mm and 70 mm, an average diameter of 3 microns and 6 microns, and an average curling degree of 10% and 20% respectively;

[0028] The first group of glass fibers is introduced into the centrifugal disc with a diameter of 300 mm by the glass liquid with a flow rate of 300 kg / h through the electric heating nozzle with a diameter of 20 mm and a heating temperature of 850 ℃, the centrifugal disc rotates at a speed of 1500 r / min, and the hole diameter of the centrifugal disc side wall small hole is 0.5 mm; the second group of glass fibers is introduced into the centrifugal disc with a diameter of 300 mm by the glass liquid with a flow rate of 500 kg / h through the electric heating nozzle with a diameter of 30 mm and a heating temperature of 850 ℃, the centrifugal disc rotates at a speed of 3000 r / min, and the hole diameter of the centrifugal disc side wall small hole is 0.8 mm.

[0029] In the preparation method of the two groups of glass fibers, the high-pressure cutting air is installed 5 cm and 15 cm below the bottom of the centrifugal disc respectively.

[0030] S3, glue spraying: each group of glass fibers is sprayed with resin glue by 8 annular nozzles; the resin glue is composed of 97.5% of phenolic resin aqueous solution with a concentration of 5% and 2.5% of waterproof agent.

[0031] S4, preparation of elastic felt for low-temperature storage tank: the two groups of glass fibers after spraying resin glue are repeatedly and uniformly attached and distributed on the collector screen belt in the negative pressure air chamber with adjustable air direction and air pressure, the speed of the collector screen belt is adjusted to uniformly control the gram weight range, and then the glass fibers are compressed to a thickness of 3 by pressure rolling after being cured in an oven at a curing temperature of 150 ℃ for 3 min. In the step S4, the mass fraction of the glass fibers in the sprayed glass fibers is 80%, and the solid mass fraction of the resin glue is 20%.

[0032] Example 2

[0033] An elastic felt for low-temperature storage tank is prepared by repeatedly crossing and stacking two groups of glass fibers after spraying resin glue, the mass percentage of the glass fibers is 90%, and the solid mass percentage of the resin glue is 10%; the length of the glass fibers of the first group of glass fiber felt is 70 mm, the diameter is 6 microns, and the curling degree is 20%; the length of the glass fibers of the second group of glass fiber felt is 150 mm, the diameter is 12 microns, and the curling degree is 30%. The main components and contents of the glass fibers are: SiO2 66%, B2O3 10%, Na2O 14%, K2O 1%, CaO 5%, and Al2O3 3%; the resin glue is composed of 99.5% resin and 0.5% waterproof agent.

[0034] The preparation method of the above-mentioned elastic felt for low-temperature storage tank, the preparation method comprises the following steps:

[0035] S1, glass liquid preparation: melting raw materials of the glass liquid to obtain the glass liquid; the main components and contents of the glass liquid are: SiO2 66%, B2O3 10%, Na2O 14%, K2O 1%, CaO 5%, and Al2O3 3%;

[0036] S2, glass fiber preparation: the glass liquid is introduced into the respective corresponding centrifugal disc through the electric heating nozzle in sequence, each electric heating nozzle and the respective corresponding centrifugal disc is a group, the glass liquid is sprayed out from the centrifugal disc side wall small hole in the form of glass filaments parallel to the horizontal plane after being heated by the electric heating nozzle; the glass filaments are vertically stretched by a 950℃ flame; the stretched glass filaments are bent by hot air with an angle of 75° with the horizontal plane, a temperature of 300℃, and a pressure of 50KPa; the bent glass filaments are cut and cooled by high-pressure cutting air with a temperature of 25℃ and a pressure of 0.4MPa, to obtain two groups of glass fibers with an average length of 70mm and 150mm, an average diameter of 6 microns and 12 microns, and an average curling degree of 20% and 30% respectively;

[0037] Among them, the first group of glass fibers is prepared by introducing the glass liquid with a flow rate of 500kg / h through the electric heating nozzle with a diameter of 40mm and a heating temperature of 950℃ into the centrifugal disc with a diameter of 500mm, the rotation speed of the centrifugal disc is 3000r / min, and the hole diameter of the centrifugal disc side wall small hole is 0.7mm; the second group of glass fibers is prepared by introducing the glass liquid with a flow rate of 800kg / h through the electric heating nozzle with a diameter of 50mm and a heating temperature of 950℃ into the centrifugal disc with a diameter of 500mm, the rotation speed of the centrifugal disc is 5000r / min, and the hole diameter of the centrifugal disc side wall small hole is 0.9mm.

[0038] Among them, the high-pressure cutting air in the preparation method of the two groups of glass fibers is installed 10cm and 20cm below the bottom of the centrifugal disc respectively.

[0039] S3, spraying resin: each group of glass fibers is sprayed with resin by 16 annular nozzles; the resin is composed of 99.5% of phenolic resin aqueous solution with a concentration of 15% and 0.5% of waterproofing agent.

[0040] S4, preparation of elastic felt for low-temperature storage tank: the two groups of glass fibers sprayed with resin are repeatedly crossed and uniformly attached and distributed on the collector mesh belt in the negative pressure air chamber with adjustable air direction and air pressure, the speed of the collector mesh belt is adjusted to uniformly control the gram weight range, and then the elastic felt for low-temperature storage tank is obtained after the pressurized curing in the oven with a curing temperature of 250°C and a curing time of 1 min, and the glass fiber thickness compression ratio is controlled between 5 during pressurization. In step S4, the mass ratio of glass fiber in the sprayed glass fiber is 90%, and the solid mass ratio of resin glue is 10%.

[0041] Example 3

[0042] An elastic felt for low-temperature storage tank is prepared by repeatedly crossing and stacking two groups of glass fibers after spraying resin, the mass ratio of glass fiber is 85%, and the solid mass ratio of resin glue is 15%; the glass fiber length of the first group of glass fiber felt is 40 mm, the diameter is 4 microns, and the crimp degree is 15%, the glass fiber length of the second group of glass fiber felt is 100 mm, the diameter is 10 microns, and the crimp degree is 25%; the glass fiber length of the third group of glass fiber felt is 50 mm, the diameter is 5 microns, and the crimp degree is 17%; the main components and contents of the glass fiber are: SiO2 60%, B2O3 15%, Na2O 10%, K2O 3%, CaO 4%, and Al2O3 7%; the resin glue is composed of 98% of resin and 2% of waterproofing agent.

[0043] The preparation method of the above-mentioned elastic felt for low-temperature storage tank, the preparation method comprises the following steps:

[0044] S1, glass liquid preparation: the raw materials of the glass liquid are melted to obtain the glass liquid; the main components and contents of the glass liquid are: SiO2 60%, B2O3 15%, Na2O 10%, K2O 3%, CaO 4%, and Al2O3 7%;

[0045] S2, glass fiber preparation: the glass liquid is introduced into the respective corresponding centrifugal disc through the electric heating nozzle respectively, each electric heating nozzle and the respective corresponding centrifugal disc is a group, the glass liquid is sprayed out from the centrifugal disc side wall small hole in the form of glass filaments parallel to the horizontal plane after being heated by the electric heating nozzle; the glass filaments are vertically stretched by 1100 DEG C flame; the stretched glass filaments are bent by hot air with an angle of 80 DEG with the horizontal plane, a temperature of 400 DEG C and a pressure of 40 KPa; the bent glass filaments are cut and cooled by high-pressure cutting air with a temperature of 15 DEG C and a pressure of 0.6 MPa, to obtain three groups of glass fibers with an average length of 40 mm, 100 mm and 50 mm, an average diameter of 4 microns, 10 microns and 5 microns respectively, and an average curling degree of 15%, 25% and 17% respectively.

[0046] In the preparation method of the three groups of glass fibers, the high-pressure cutting air is installed 6 cm, 18 cm and 8 cm below the bottom of the centrifugal disc respectively.

[0047] In the preparation method of the three groups of glass fibers, the high-pressure cutting air is installed 6 cm, 18 cm and 8 cm below the bottom of the centrifugal disc respectively.

[0048] S3, glue spraying: each group of glass fibers is sprayed with resin glue by 12 annular nozzles; the resin glue is composed of 98% of phenolic resin aqueous solution with a concentration of 10% and 2% of waterproof agent.

[0049] S4, preparation of elastic felt for low-temperature storage tank: the three groups of glass fibers sprayed with resin glue are repeatedly and uniformly attached and distributed on the collector screen belt in the negative pressure air chamber with adjustable air direction and air pressure, the speed of the collector screen belt is adjusted to uniformly control the gram weight range, and then the glass fibers are pressed and solidified in the oven with a solidification temperature of 200 DEG C and a solidification time of 2 min, and then the glass fibers are wound after being pressed to obtain the elastic felt for low-temperature storage tank, and the thickness compression ratio of the glass fibers is controlled at about 4 during pressing. In the step S4, the mass ratio of the glass fibers in the glue-sprayed glass fibers is 85%, and the solid mass ratio of the resin glue is 15%.

[0050] The low-temperature storage tank prepared in Examples 1-3 is cut into a test sample of a specified size with the elastic felt, and the tensile strength of the test sample is tested according to the provisions of GB / T17911; the thermal conductivity of the test sample at 0 DEG C is tested according to the national standard GB / T 10294-2008; the resilience coefficient of the test sample is tested according to the provisions of T / CSTM 00392, and the detection indexes are as follows:

[0051] Strength kPa Elasticity Coefficient Thermal Conductivity W / (M.K) Example 1 18 0.45 0.038 Example 2 20 0.44 0.039 Example 3 22 0.48 0.036

[0052] It can be known from the detection data that the elastic felt for low-temperature storage tank prepared by the application has good resilience, high strength, and excellent heat insulation performance; the preparation method is online one-step forming, has few preparation processes, is good in stability, and has great market prospect.

[0053] The above only describes the preferred embodiments of the application and is not used to limit the application, and any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A method for producing an elastic mat for a cryogenic storage tank, characterized by, The preparation method comprises the following steps: S1, glass liquid preparation: raw materials of the glass liquid are melted to obtain the glass liquid; main components and contents of the glass liquid are as follows: SiO255-66%, B2O310-19%, Na2O 8-14%, K2O 1-4%, CaO 1-5%, Al2O33-12%; S2, glass fiber preparation: the glass liquid is introduced into respective corresponding centrifugal discs through electric heating nozzles respectively, each electric heating nozzle and respective corresponding centrifugal disc is a group, the glass liquid is sprayed out from the centrifugal disc side wall small holes as a glass stream parallel to the horizontal plane after being heated by the electric heating nozzle; the glass stream is vertically stretched by a 950-1250℃ flame; the stretched glass stream is bent by hot air with an angle of 75-85° with the horizontal plane, a temperature of 300-500℃ and a pressure of 30-50KPa; the bent glass stream is cut and cooled by high-pressure cutting air with a temperature of 5-25℃ and a pressure of 0.4-0.7MPa, to obtain two groups of glass fibers with an average length of 20-70mm, 70-150mm, an average diameter of 3-6 microns, 6-12 microns respectively, and an average curling degree of 10%-20%, 20%-30% respectively, the lengths, diameters and curling degrees of the glass fibers of the two groups of glass fiber mats are different; S3, glue spraying: each group of glass fibers is sprayed with resin glue by 8-16 annular nozzles respectively; S4, preparation of elastic mat for low-temperature storage tank: the two groups of glass fibers sprayed with resin glue are repeatedly and uniformly attached and distributed on the collector screen belt in the negative pressure air chamber with adjustable air direction and air pressure, the speed of the collector screen belt is adjusted to uniformly control the gram weight range, the elastic mat for the low-temperature storage tank is obtained after passing through the oven for pressure curing, the curing temperature is 150-250℃, the curing time is 1-3min, and then the pressure is applied for winding.

2. The method of claim 1, wherein the low-temperature storage tank elastic felt is prepared by the steps of: In the step S2, the first group of glass fibers is introduced into a centrifugal disc with a diameter of 300-500mm by the glass liquid with a flow rate of 300-500kg / h through an electric heating nozzle with a diameter of 20-40mm and a heating temperature of 850-950℃, the centrifugal disc has a rotating speed of 1500-3000r / min, and the centrifugal disc side wall small hole has a diameter of 0.5-0.7mm.

3. The method for preparing elastic felt for cryogenic storage tanks according to claim 1, characterized in that, In the step S2, the second group of glass fibers is introduced into a centrifugal disc with a diameter of 300-500mm by the glass liquid with a flow rate of 500-800kg / h through an electric heating nozzle with a diameter of 30-50mm and a heating temperature of 850-950℃, the centrifugal disc has a rotating speed of 3000-5000r / min, and the centrifugal disc side wall small hole has a diameter of 0.8-0.9mm.

4. The method of claim 1, wherein the low-temperature storage tank elastic felt is prepared by the steps of: In the step S2, the high-pressure cutting air in the preparation methods of the two groups of glass fibers is installed 5-10cm and 15-20cm below the bottom of the centrifugal disc respectively.

5. The method for preparing elastic felt for cryogenic storage tanks according to claim 1, characterized in that, In the step S2, the glass fibers are multiple groups, and the length, diameter and curling degree indexes of other groups of glass fibers are between those of the first group of glass fibers and the second group of glass fibers.

6. The method of claim 1, wherein the resin glue in step S3 is composed of 97.5-99.5% of phenolic resin aqueous solution with a concentration of 5-15% and 0.5-2.5% of waterproofing agent.

7. The method for preparing elastic felt for cryogenic storage tanks according to claim 1, characterized in that, In step S4, the glass fiber accounts for 80-90% of the mass of the sprayed glass fiber, and the resin glue accounts for 10-20% of the solid mass.

8. The flexible blanket for a cryogenic storage tank produced by the method for producing a flexible blanket for a cryogenic storage tank according to any one of claims 1 to 7, characterized by The elastic felt for low-temperature storage tanks is formed by repeatedly crossing and stacking two groups of glass fibers sprayed with resin glue, wherein the glass fiber accounts for 80-90% of the mass, and the resin glue accounts for 10-20% of the solid mass. The first group of glass fibers has a length of 20-70 mm, a diameter of 3-6 microns, and a curling degree of 10-20%, and the second group of glass fibers has a length of 70-150 mm, a diameter of 6-12 microns, and a curling degree of 20-30%.

9. The flexible blanket for cryogenic storage tanks of claim 8, wherein, The glass fibers are composed of multiple groups, and the length, diameter, and curling degree of the glass fibers in other groups are between those of the first group and the second group.

10. The flexible blanket for cryogenic storage tanks of claim 8, wherein, The main components and contents of the glass fibers are: SiO2 55-66%, B2O3 10-19%, Na2O 8-14%, K2O 1-4%, CaO 1-5%, and Al2O3 3-12%; and the resin glue is composed of 97.5-99.5% of resin and 0.5-2.5% of waterproofing agent.