| 摘要 |
PROBLEM TO BE SOLVED: To reduce man-days for a work and increase reliability relative to vacuum retension of the entirely vacuum heat insulation box by providing a connection board holding piping members or electric source cords to penetrate into the board, and constituting the rest gap of a foaming heat insulation material, in the entirely vacuum heat insulation box. SOLUTION: A connection board provided with a little larger through holes than a passing member is provided. After letting it pass, it is connected to instruments in the refrigerator. Some of the passing members are electric source cords, a refrigerant pipe, and a drain pipe. A foaming urethane 34 having closed bubbles and cyclopentane as a foaming agent is filled into a cavity of the crust 35 obtained by vacuum forming of thermoplastic resin, and provided with a pipe-like through hole parts 32 corresponding to the through hole in the inside in the connection board 33. More particularly, a raw material mixture of foaming urethane 34 as a heat insulation material is injected in a state that it is fixed in a foaming jig retained at 45 deg.C. Thereafter, the inside of the crust 35 is filled with the foaming urethane with foaming and expansion of the resin.
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