| COOL-BIND™ Melts Faster Than Standard EVAs |
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| Nordson Corporation recently compared the melt rate of National's new 250°F COOL-BIND EVA with standard 350°F EVAs using Nordson's PM-Series pre-melters. Nordson found that not only does COOL-BIND run at a cooler temperature but also melts faster than standard EVAs, even at 275°F. As shown in the chart, Nordson's PM-250 premelter, rated at 250 lb/hour, melted COOL-BIND at 430 lb/hour, while the PM-150 melted COOL-BIND at a rate of 230 lb/hour. The conclusion: With the fastest melt rate, COOL-BIND will meet high volume demands and use less energy in the process because of its lower temperature. National esti-mates that hot melt energy consumption decreases as much as one-third when temperatures drop from 350°F to 250°F. |
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| Concave Spine |
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| The desired appearance when perfect binding a soft cover book is to have the backbone perfectly square. This aids in trimming and stacking off, as well as providing the desired aesthetics. Occasionally, the spine has a concave appearance, where the center signatures appear to have moved away from the flat back. This effect is most commonly seen on books of 1-inch or greater bulk that generally have highly glossed paper. |
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| The following can cause this problem: |
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- Insufficient clamp pressure. As machines age, the mechanical pressure holding the bookblocks in the clamps weakens. When the saws rough the backbone, the center of the book tends to slide upwards.
- Excessive pressure from the cover station. If the cover station moves too high when applying the cover, slippery pages may slide upwards in the book.
- First wheel in the glue pot too close to the book. The book hitting the first wheel in the glue pot could also send the center of the book upwards.
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| The solution to each one of the above is to be sure the clamp pressure is tight, within the specifications of the binder manufacturer. |
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