Ammonia Mercerization of Denim 牛仔布液氨絲光. The use of ammonia in mercerization has been known since the 1930 s and was developed

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1 Ammonia Mercerization of Denim 牛仔布液氨絲光 The use of ammonia in mercerization has been known since the 1930 s and was developed commercially for fabric processing around 1970 in what was originally known as the Tedesco process, which was subsequently acquired by the Sanforized company and made well-known as the Sanfor-Set process. 自 1930 年液氨絲光問世, 約在 1970 年開始用來處理織物, 此工藝稱為 Tedesco( 液氨絲光 ) 工 藝, 隨後桑福公司開始採用此法, 開創了著名的 Sanfor-Set 工藝 By combining ammonia mercerization and Sanforizing in a single step shrinkage control is greatly improved in denim. In contrast to caustic mercerization, the fabric is softer, semipermanent press properties result and in the case of twill fabrics, there is less seam-puckering in garments, less leg- twist and edge-fraying. Unlike caustic mercerization, the fabric is not degraded, avoiding a harsh hand even after multiple washings. The resistance to abrasion, tear and tensile is significantly improved.

2 將液氨絲光及預縮結合成一個單一的縮率控制工藝, 在牛仔布發展中取得了巨大的進步 與堿絲光對比, 織物更柔軟 採用這種半滲透壓法, 對於斜紋織物, 成衣縫和起皺更少, 腿部折皺及褲邊擦傷更少 不同於液堿絲光, 織物不會降級, 即使多次水洗後也不會變硬 抗磨損, 撕裂性及強度都得到明顯的提升 The difference in effect as opposed to caustic mercerization is because with ammonia, there is less fiber-swelling, therefore the fibers are more pliable, which allows them to bend and recover more easily when tension or stress is applied. In garments that are fabricated from ammonia treated-fabrics, the garment life is longer after long periods of wear and repeated washings, improving sustainability. 與堿絲光在效果上相比, 纖維膨脹小 更柔軟, 因此當施加張力或壓力時更容易彎曲及恢復變 形 用液氨絲光整理的布做成的成衣, 更耐磨及可經多次水洗, 衣物壽命更長 The much smaller molecular size of ammonia allows it to penetrate completely into every fiber of the fabric, unlike caustic which causes such rapid fiber- swelling that the caustic is blocked at the surface of yarns, preventing further penetration. The surface tension of ammonia at 26 dyes/cm is a third that of caustic (NaOH). Additionally, at normal mercerization concentrations of caustic (23%/30 Baume), sodium hydroxide forms a hepta-hydrate with water (NaOH 7H₂O), which results in a slow-moving, bulky group. 氨的分子量更小, 可以完全滲透到織物的每根纖維, 而採用堿絲光時, 纖維快速膨脹, 堿被鎖定在紗線的表面, 阻礙了堿液進一步滲透 氨的表面張力 26 dyes/cm, 是堿 (NaOH) 的三分之一 另外, 正常絲光時堿的濃度 (23%/30 Baume), 氫氧化鈉與水形成 NaOH 7H₂O, 會形成緩慢移動的大分子團 The permanent-press effects are achieved without the use of cross-linking resins, however, the commonly-used resins are soluble in ammonia and a combination resin finish and mercerizing can be achieved if a soluble catalyst is employed. Additionally, ammonia acts as a formaldehyde-scavenger and resin-treated fabrics that are ammonia treated will produce no free-formaldehyde.

3 滲透壓法無需使用架橋樹脂, 但是, 常用的樹脂溶於氨, 如採用可溶性催化劑, 可以將樹脂整理 與絲光相結合 另外, 氨可作為甲醛捕捉劑, 樹脂液氨整理過的織物不會產生游離甲醛 As a rule, fabric shrinkage depends on the time of exposure to the ammonia, with 80% of the shrinkage occurring in the initial 6 seconds. Very close control of final shrinkage is achieved by fabric tension in the ammonia application in combination with compressive shrinkage. 依規律, 織物縮率取決於滯留於氨中的時間,80% 的縮率控制發生於 6 秒這內 在織物絲光及預 縮聯合工藝中控制布的張力從而控制最終縮率 By 1974, the primary application of ammonia mercerization was for treatment of heavy-weight cotton fabrics such as denim and corduroy, which are difficult to properly mercerize with traditional caustic treatments. The ammonia process was intended as a replacement for conventional mercerizing for both fabrics and in mercerizing sewing threads (Petrograd process) 年以前, 液氨絲光用於處理重磅棉布如牛仔及燈芯絨, 這兩種織物用正常的堿絲光很難達到 好的效果, 因此對於這兩種織物及縫紉線絲光, 液氨絲光勢必會取代傳統的堿絲光 The original process consisted of passing the fabric though a bath of liquid ammonia with 100% pickup for approximately 10 seconds. The ammonia was removed with dry heat applied by passing over blanketed, steam heated dry cans which removed about 90% of the ammonia which was then recovered by a recovery plant consisting of large, pressurized towers and made available for recycling. The rest of the ammonia, which chemically bonded to the cellulose, was removed by light steaming. This residual ammonia can be recovered and recycled for producing chemicals such as fertilizers. The original ammonia recovery methods required a large capital investment which limited acceptance in the textile industry, however, a more recent design employed by the Lafer company replaces the dry/steam method of ammonia recovery with a dry/dry process that eliminates the need for an expensive recovery operation. This process also has the advantage of allowing denim to be processed on the same machine without contamination of non-denim fabrics as well as avoiding the problem of backstaining with denim that occurs in caustic mercerization, since no water is required for washing. Some backstaining

4 can occur with ammonia units that use dry/steam methods of ammonia removal. This unit also does not employ a felt calendar, which can also transfer contamination from denim. 原始工藝包括織物穿過液氨, 軋吸率 100%, 最大 10 秒 再通過呢毯加熱以去除液氨, 採用這種蒸汽烘筒加熱可去 90% 的氨, 這部分氨通過大型壓力塔回收, 迴圈使用 剩餘的氨經過化學反應聯接到纖維素上, 輕微蒸一下即可去除 這些氨可以回收並用作肥料 這種原始液氨回收方法需要大量的資金投入, 在紡織行業很難接受 但是,LAFER 公司新研發的烘乾 / 烘乾液氨回收方法取代了氨烘乾 / 汽蒸工法, 減少了對回收設備的大量投入 此工藝有一個優點是 : 牛仔布可用在同一機器上, 無需水洗處理, 因此不會污染非 - 牛仔布織物, 另外可以避免堿絲光中的背面污染的問題 在去除氨時, 如採用烘乾 / 汽蒸方法, 可能會產生背面污染 而 LAFTER 回收方法無需呢毯烘乾, 因此不會產生污染的問題 Ammonia- mercerization provides a higher dry-crease recovery and higher shrinkage consistency than caustic mercerization, especially with the dry-steam method of recovery. However, caustic mercerization still has an advantage with regard to luster and improved depth of color in dyeing, although the uniformity of dyeing after mercerization is significantly improved with ammonia. Ammonia treatment results in a more rounded cotton fiber, which scatters light more, in turn resulting in a luster that is less bright. An additional advantage of ammonia mercerization is the absence of alkaline oxy-cellulose that results with caustic treatments, which is evidenced by strength-losses and dyeing variation. The lower ph of ammonia allows safe treatment of more sensitive fibers like wool or silk. 與堿絲光相比, 尤其是採用烘乾 汽蒸的回收方法, 液氨絲光後處理的織物, 幹皺折回複性更高, 縮率持久性更好 但是堿絲光仍有其優點, 有光澤及上色更深 而對於液氨絲光, 染色會更均勻 液氨絲光後, 纖維更圓, 散紗少, 因此光澤少 另外採用液氨絲光不會產生堿絲光中的堿氧化纖維, 而這種氧化纖維會降低織物強度, 影響染色均勻性 對於比較敏感的織物如毛或絲, 氨 PH 值低, 處理起來會更安全 With caustic treatments of fabrics like denim, the elimination of washing required in caustic mercerization avoids the problems with removing caustic. Mercerizers are not normally equipped with drum washers for removal of caustic from heavy cotton fabrics and contamination

5 remains on the fabric at the time of drying which results in damage to cotton. The use of acetic acid to neutralize creates a problem with the formation of sodium acetate, which produces a very harsh feel. Tension control is important in both ammonia and caustic mercerization for improved fabric tenacity and elongation. Moisture regain is improved in both if tension is applied prior to fiber swelling. 對於牛仔布堿絲光, 需要大量水洗以去除織物上的堿, 絲光者通常不會採用滾筒洗衣機以去除生 磅織物上的堿, 污染仍殘留在織物上, 在烘乾時棉紗會受損傷 另外使用醋酸中和會產生醋酸 鈉, 這樣織物手感會很硬 對於液氨絲光及堿絲光, 對提高織物張力及延伸率張力控制都至關重要, 如張力大於織物膨脹 力, 回潮率會增加