| 摘要 |
PURPOSE:To enable to cover a steel pipe by giving heat shrink-ability, self- restoring properties an steel pipe tightening stress, by giving a specific shrinkage factor by heating and orienting an unoriented tape. CONSTITUTION:An unoriented tape to be used is a thing obtained by providing an adhesive agent layer on the surface of a piece of an unoriented crosslinked polyolefin sheet and as for the adhesive agent layer, a thing which is superior in adhesive force at the normal temperature, softened through heating and fluid to a tiny uneven rough surface of the surface of a steel pipe is desirable. The steel pipe 1 is made to rotate at a predetermined position by an under roll and the outside of the steel pipe 1 which is being rotated is heated desirably up to 100-250 deg.C in order by a steel pipe heating equipment 3. Then an oriented tape 8 obtained by giving 10-30% shrinkage factor to the unoriented tape 7 by heating and orienting the same is fed on the outside of the steel pipe 1 in order through a tape feed equipment 6. The oriented tape 8 is wound spirally round the outside of the steel pipe 1 by overlapping the oriented tape 8.
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