Molds stop blocks

GRTP cannot be stamped in molds sitting on stop blocks. Stop blocks must be designed for safety purposes only, i.e., to prevent the empty mold surfaces from cracking into each other. Therefore, stop blocks, pin retractors, keys, heelblocks, spacers, etc., must permit the empty mold to close within 0.020 in. 

Stock, n. stick, staff stock rod, pole block trunk, butt, stump main part, body story, floor (of a building) mold (SricA ) clamp (Brewing, etc.) vat, back, stock-, utterly, entirely. -bHnd, a. stone-blind, stocken, v.i. stop, slacken, stagnate curdle ... 

Zinc borate (Borogard ZB, U.S. Borax Inc.) in amonnts of 0.5,1 and 2% (w/w) in the composite materials practically stopped the microbial degradation in the latter, when exposed in the AWPA laboratory soil block procednre. In all the cases, weight loss valnes were less than 1.1%. Thns, the data clearly demonstrated the significant improvement in protection against fnngal decay in the presence of the said amount of zinc borate. It was noticed, however, that the nse of zinc borate did not completely control snrface mold on WPC decks exposed in ontdoor held tests, but improved the visual appearance of the composite boards [2]. 

The problem is that almost all polymers have some contamination on the surface. This comes accidently fi-om handling or storage contamination, or, most importantly, fi om the diffusion of oily or waxy additives from the bulk polymer to the surface of the polymer. These additives can be antioxidents, anti-blocking agents, mold release, plasticizers, lubricants, etc. The diffusion of the additives usually cannot be stopped because they are designed to diffuse to the surface to perform their desired role. Unfortunately, when they reach the surface they cover-up the surface moieties left by the plasma treatment and the effects of that treatment may disappear. 

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