| 摘要 |
Business forms having longitudinal and transverse patterns of pressure activated cohesive requiring a sealing force of at least about 50 lbs. per lineal inch are sealed preferably by a single pass through a nip formed by first and second rollers. The first roller is a larger diameter substantially smooth surfaced roll, while the second roller is a small diameter serrated or ribbed roll, e.g. having serrations or ribs having a dimension substantially parallel to the axis of rotation of about 0.04-0.1 (e.g. about +E,fra 1/16+EE ) inches, with spaces therebetween of between about 0.2-0.1 inches (e.g. between about +E,fra 1/32+EE -+E,fra 1/16+EE ) inches. Preferably the serrations or ribs are oppositely directed angled serrations or ribs on different halves of the second roll, each making an angle of at least about 10 DEG with respect to a plane substantially transverse to the axis of rotation. The rolls are typically 4-12 inches in length, and when 6 inches in length or more, a reinforcing roll preferably engages the second roll to prevent bowing of the second roll.
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