Suitable Methoxysilane and Its Oligomer for Tensile Strength Improvement in Treated Paper Using Titanium Butoxide as Reaction Accelerator

摘要

紙の引張強度向上をはかる目的で三種類のメトキシシラン（テトラメトキシシラン（TMOS），メチルトリメトキシシラン （MTMS），ジメチルジメトキシシラン），2種のオリゴマー（TMOSオリゴマー，MTMSオリゴマー），および反応促進剤とし てチタンブトキシドを用いた反応液を原紙に含浸させた。メトキシシランの場合，最高の含浸量を与えたのはTMOS溶液であ り7.2g／m~2であった。また，最高の引張強度はMTMS溶液であり4．3kN／m（原紙の130％増）であった一方，オリゴマーの 場合，含浸量および引張強度ともに最高値を与えたのはMTMSオリゴマー溶液であり，それぞれ50g／m~2と6，8kN／m（200％増） であった。全体的にオリゴマー溶液と比較してモノマー溶液が低い備になったのは，モノマーの揮発性の高さに起因し，十分 な塗工量が得られず低い値になったものと思われる。MTMSオリゴマー溶液が最も高い値を与えた理由は，その分子構造に由 来するものと推測した。すなわち，MTMSはその分子内に1個の非加水分解性置換基（メチル基）と，3個の加水分解性置換 基（メトキシ基）をもっているため，得られた高分子鎖はメチル基由来の柔軟性とメトキシ基山来の硬さのちょうど良いバラ ンスをもっているものと推測した。重合度の異なるMTMSオリゴマー（n＝3．1，4．4，6．3，8．7，12．4，26．1）を糊い，重合 と引張強度の関係を調べたが,ほとんど差はなかった。%For investigating the suitable methoxysilane and its oligomer for improving the tensile strength of treated paper after its hydrolysis and poly-condensation, three methoxysilanes (tetramethoxysilane (TMOS), methyltrimethoxysilane (MTMS) and dimethyldimethoxysilane) and two oligomers (TMOS and MTMS oligomers) were impregnated into the base paper using titanium butoxide as the reaction accelerator. Among the three methoxysilanes, the highest impregnated weight (7.2 g/m2) was obtained when a TMOS solution was used. The highest tensile strength was obtained when an MTMS solution was treated (4.3 kN/m, 130 % increase compared to the base paper). On the other hand, for the two oligomers, the highest weight was 50 g/m2 and the highest strength was 6.8 kN/m (200 % increase) when an MTMS oligomer solution was treated. These differences in the improvement of the weight and strength between the monomer solutions and the oligomer ones were due to the monomer's high volatility. The reason why the MTMS oligomer produced the highest strength treated paper is attributed to its molecular characteristics. Because the MTMS has one unhydrolyzable group (methyl group) and three hydrolyzable groups (methoxy groups), it is assumed that the balance between the flexibility resulting from the methyl group and the hardness from the methoxy groups produced the moderate tension in the generated polymer. The MTMS oligomer has the same balance as the MTMS. Among the MTMS oligomers having different degrees (n = 3.1, 4.4, 6.3, 8.7, 12.4 and 26.1), there was only a slight difference in strength. The most suitable methoxysilane compound for improvement of the tensile strength was the MTMS oligomer.