Technical requirements for cold storage insulation materials
Insulation materials for cold storage should meet the following conditions:
1. The thermal conductivity is small, so that a thinner thermal insulation layer can be used to obtain a better thermal insulation effect.
2. Low density and low price.
3. Good moisture resistance, frost resistance, firmness, high compressive strength, and durability to ensure long-term use.
4. Well thought out fire resistance, unnatural, and not supporting combustion, so as to improve the fireproof performance of the cold storage.
5. It does not produce any peculiar smell, does not absorb peculiar smell, and does not emit toxic substances, which is of great significance to food storage in cold storage.
In addition, the cold storage insulation material should also have good corrosion resistance and not breed worms or other bacteria.

Moisture-proof materials commonly used in cold storage
Moisture-proof and steam-proof materials require high vapor penetration resistance, low density, good toughness, ease of construction and guarantee of construction quality. Commonly used moisture-proof and vapor-proof materials for cold storage are petroleum asphalt, linoleum, asphalt waterproof plastic and polyethylene plastic film. Among them, petroleum asphalt has good waterproof and steam performance, and has certain characteristics of elasticity, low temperature resistance, and stable moisture and vapor barrier performance. If used in combination with linoleum, it can achieve a good moisture and vapor barrier effect. Plastic film has good air permeability, low water absorption, high mechanical strength, and good flexibility, but it has poor aging resistance and low temperature resistance. At present, most cold storages still use asphalt and linoleum as moisture and vapor barriers.
(1) Asphalt, linoleum and other moisture-proof and vapor-proof materials
Petroleum bitumen is a moisture-proof and vapor-proof material with stable performance, strong adhesion and excellent moisture-proof performance. It is often combined with linoleum to form one felt and two oils or two felts and three oils. Generally, No. 60 petroleum pitch is selected as the moisture-proof and vapor-proof material for cold storage floor, and No. 10-30 petroleum pitch is selected for exterior walls and roofs. As the linoleum, choose 359-500g petroleum asphalt linoleum.
(2) Moisture-proof and vapor-proof plastic film materials
There are polyethylene and polyvinyl chloride films. The performance of polyethylene film depends on resin density, melt flow rate and molding method. Films for cold storage must have high tensile strength, tear strength, impact strength and excellent air tightness. Polyethylene films are generally bonded with polyvinyl chloride adhesives. Polyvinyl chloride film is a moisture-proof and vapor-proof material with excellent gloss, transparency, anti-odor penetration, and air tightness. Usually, a 0.2mm thick transparent polyvinyl chloride film is used.