Adhesive strength of gummed paper sealing tape

NOTES FROM THE NATIONAL BUREAU OF STANDARDS.*

A DOMESTIC SUPPLY OF FLAX AND LINEN.

The present difficulty in obtaining normal supplies of flax and linen from Europe has renewed interest in the possibility of developing a domestic source of this valuable fiber. The Textile Foundation in cooperation with the Bureau has com- pleted a preliminary survey of the present situation. This included interviews with those in charge of the experiments being conducted by the Tennessee Valley Authority and the Georgia School of Technology, with several paper manufac- turers, with spinners and weavers of linen in New England, and with those who are growing flax and preparing fiber in Oregon.

The United States now produces about half the amount of fiber needed for coarse linen goods. Increased production seems to be largely a matter of economics, although the need for certain technical improvements is obvious.

No fiber of the quality required for fine linen goods has ever been produced in this country. To accomplish this would necessitate the development of an entirely new in- dustry based upon individual craftsmanship rather than mass- production. It would, therefore, appeal but little to Ameri- can psychology.

The survey shows that additional information is needed about the structure and composition of the flax fiber, and about the mechanism of present methods of preparation. The complete report of this work will be published in pam- phlet form by the Textile Foundation.

ADHESIVE STRENGTH OF G U M M E D PAPER SEALING TAPE.

The evaluation of the gummed paper tape used so widely for sealing fiber shipping containers will be on a utilitarian basis only if the strength of the seal it will form is predicted. The strength of the ultimate seal will depend on two factors:

* Communicated by the Director. 71

7 2 NATIONAL BUREAU OF STANDARDS NOTES. [J. F. I.

the s t rength of the paper tape itself and the s t rength of the bond which the adhesive forms between the carton and the paper tape. The first factor is readily determined by the conventional s t rength tests applied to paper, but until re- cently no satisfactory measure of adhesion could be obtained. However, a method of determining this factor has now been developed commercially and has met the requirements set up by the Bureau in connectinn with the preparation of a Federal specification.

The new test, which combines a hand-operated tape mois- tener with a motor-driven, electrically t imed and synchronized apparatus for affixing the tape with controlled pressure to a s tandard test paper, measures the force required to break the seal after a definite setting period. The test seal is slipped apar t by applying the force in a manner tha t simulates the stress exerted by the flaps of a fiber box on the seal which holds them in place. The apparatus is known as the Harn- den-McLaurin Gummed Tape Tester.

FIBER TILE BOARDS.

Fiber tile boards, a relatively new type of interior finishing material, have been tested at the Bureau to determine their probable lasting quality. This material which is suitable for a variety of uses, appears to have a place in low cost house construction because of its relative cheapness and ease of in- stallation. The tile boards consist of a vegetable-fiber board in large sheets having on one side a dense, hard coating which is scored to resemble ceramic tile.

The boards were subjected to cycles of s teaming and dry- ing and were tested for density, expansivity, flexural prop- erties, resistance to household cleaners, staining, and resist- ance of the finish to impact. They were subjected to condi- tions more drastic than would ordinarily be encountered in service to produce in a relatively short t ime results tha t would be likely to arise from long periods of service.

In general, the fiber tile showed good resistance to staining, to abrasive cleaning powders, and impact. However, the surface coatings were in most instances damaged by the cycles of s teaming and drying, especially at the edges and in some