脱灰材料性质的关键影响因素研究

Investigation of Key Factors on Properties of Deliming Agents

采用硫酸铵、少氨脱灰剂(硫酸铵25%)、硼酸、含硼脱灰剂(硼酸50%)和己二酸对浸灰牛皮进行脱灰。结果表明:因为硫酸铵和硼酸的pKa=9.2,所以硫酸铵、少氨脱灰剂、硼酸和含硼脱灰剂能与灰皮中的灰碱作用后形成pH 8～9的缓冲系统,并快速渗透灰皮,得到柔软的脱灰裸皮;而己二酸因pKa=4.4,在脱灰过程中无法形成pH 8～9的缓冲系统,渗透性较差,制得的脱灰裸皮柔软度也欠佳。由此可见,全部或部分选用pKa9左右的酸性物质作为脱灰材料对开发性能更优的无氨无硼脱灰剂具有重要意义。

The limed cattle hide pelts were delimed with ammonium sulfate, low-ammonia deliming agent (ammonium sulfate 25%), boric acid, boron-containing deliming agent (boric acid 50%) and adipic acid. The results showed that ammonium sulfate, low-ammonia deliming agent, boric acid and boron -containing deliming agent formed pH 8-9 buffer systems after reacting with lime and alkali in limed pelts because the pKa values of ammonium sulfate and boric acid are 9.2. Additionally, they penetrated limed pelts fastly and produced soft delimed pelts. Adipic acid did not form a buffer system of pH 8-9 during deliming due to its pKa of 4.4. Moreover, adipic acid penetrated relatively slowly, and the delimed pelt obtained was not soft enough. These results suggested that fully or partially using acidic components with a pKa about 9 is of great significance for development of ammonia-free and boron-free deliming agents with better performance.