Grain impregnation

Grain impregnation is used to improve the firmness of the buffed grain layer. The impregnating float or liquor has to absorb into the leather and must not become deposited at the surface. To this end, very dilute, finely divided acrylate dispersions (solids content about 10 %) are applied in combination with capillary-active substances known as penetrators. 

Depending on the cmst leather used, the adhesion of the finish layer to the leather has to be improved in some cases by means of a separate base coat. Adequate adhesion is the precondition for many application properties and important to achieve the required physical fastnesses for the ready-produced leather articles. Soft, finely divided polyurethane dispersions have won out in this sector over polyacrylate dispersions. 

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Fig. 20 Transmission electronmicrographs of hypoxic H9C2 cardiocytes treated with silver grains impregnated IL or PL. Silver grains in seen intracellularly in IL treated cells arrows, arrow heads represents 1 gm. (From Ref.[ " l)...

Timber species also vary in the treatability of the heartwood - with preservatives in an impregnation plant, and are classified into four categories according to the depth of penetration which can be achieved permeable (complete penetration) moderately resistant (6-18 mm lateral penetration) resistant (3-6 mm lateral penetration) and extremely resistant (no appreciable lateral and very little end-grain penetration). 

It was obtained by a pre-treatment of fresh impregnated HMOR in flowing air, up to 773 K. In these conditions, as detected by TEM, EDS and UV-visible spectroscopy (not shown, [12]), a fraction of Co2+ species, exchanged in the pores of HMOR, migrates on the outside of the zeolite grain, to form Co304 on the external surface of the HMOR grain. 

Hart Powder (1888). A powder patented in 1888 in England, made by impregnating the grains of KC103 with a solution of sugar, or with a liquid hydrocarbon Refs Cundill (1889) in MP 6, 10 (1892)... 

Janite. A large grain, black blasting powder impregnated with NG. It was used to a limited extent for excavation work on the Isthmus of Corinth in Greece Ref Daniel (1902), p 386... 

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