纖維素纖維是全世界紡織物和非紡織物應用中最廣泛使用的纖維之一。這包括天然纖維素纖維，例如棉、麻和亞麻；及再生纖維素纖維，例如黏膠、莫代爾、萊塞爾、銅氨纖維、富纖等。它還包括醋酸纖維素，二醋酸纖維素和三醋酸纖維素二者。由於它們的化學結構，它們提供了非常好的穿著舒適性和其它有利的性質。
然而，這種化學結構也有一些缺點：纖維素纖維會經受高溫處理，如高於170℃，以實現不同的性能，如預定形，以保持尺寸穩定性(190-195℃)，或包含聚酯纖維，聚酯纖維是進行用於分散染料染色(210-220℃；通過熱空氣處理，用於將分散染料固定在聚酯纖維內)的熱溶過程或用於最終製品(例如胸罩或鞋(190℃))的模塑過程所需的。然而，這樣的處理導致纖維素纖維變色(變黃)。這樣的變黃不僅對未染色(即，螢光增白的)纖維素纖維不利，而且對打算用淺淡或亮色染色的纖維素纖維也是不利的。除其它外，這就是為什麼胸罩材料的襯墊很少使用纖維素模塑，除了剪裁和縫製補足。最麻煩的纖維共混物由氨綸/斯潘德克斯和聚酯(尤其紡織物)與纖維素纖維或再生纖維組成。
這個問題的已知解決方法是在高溫處理之前或在高溫進行額外氧化漂白步驟之後在pH 5或略低的pH(較佳在pH 5-pH 4之間)酸性處理。
然而，由於隨後的過程步驟或纖維素纖維對酸性條件的敏感性，酸處理或洗滌並不總是可能的。例如，過量的酸可導致酸水解，從而使纖維不可挽回地變弱或甚至完全破壞。由於分散染料在這樣的酸性條件下的一般不穩定性，包含聚酯和應用熱溶染色的纖維不能在pH 4-5處理。
歷史上通過用1-5g/l硼砂(即四硼酸二鈉)處理纖維素纖維來減輕變黃。然而，今天這已被Öko-Tex禁止。
Cellulose fibers are among the most widely used fibers in textile and non-woven applications worldwide. This includes natural cellulosic fibers such as cotton, hemp and flax; and regenerated cellulosic fibers such as viscose, modal, lyocell, cupro, rich fiber, etc. It also includes both cellulose acetate, cellulose diacetate and cellulose triacetate. Due to their chemical structure, they offer very good wearing comfort and other advantageous properties.
However, this chemical structure also has some disadvantages: cellulose fibers are subjected to high temperature treatment, such as above 170°C, to achieve different properties, such as pre-shaping, to maintain dimensional stability (190-195°C), or to contain polyester Fibers, polyester fibers are subjected to a heat-melting process for disperse dyeing (210-220°C; by hot air treatment for fixing disperse dyes in polyester fibers) or for final products such as bras or shoes ( 190°C)) required for the molding process. However, such treatment causes discoloration (yellowing) of the cellulose fibers. Such yellowing is not only detrimental to undyed (ie, fluorescently whitened) cellulosic fibers, but also to cellulosic fibers intended to be dyed with light or bright colours. Among other things, this is why the padding of bra materials is rarely molded using cellulose, except for cut and sewn toppings. The most troublesome fiber blends consist of spandex/spandex and polyester (especially textiles) with cellulosic or recycled fibers.
A known solution to this problem is acidic treatment at pH 5 or slightly lower (preferably between pH 5-pH 4) before high temperature treatment or after an additional oxidative bleaching step at high temperature.
However, acid treatment or washing is not always possible due to subsequent process steps or the sensitivity of the cellulose fibers to acidic conditions. For example, excess acid can lead to acid hydrolysis, which irreparably weakens or even completely destroys the fibers. Fibers comprising polyester and applying thermosol dyeing cannot be processed at pH 4-5 due to the general instability of disperse dyes under such acidic conditions.
Yellowing has historically been mitigated by treating cellulose fibers with 1-5 g/l borax (ie disodium tetraborate). However, today this is banned by Öko-Tex.
根據本發明，保護劑包含羥基(取代的)鏈烷酸和氧代鏈烷酸鹼土金屬鹽和鋅鹽。鹼土金屬較佳為鎂。合適的保護劑為例如TP1740，可購自Brueggemann Chemical, Germany。可較佳將保護劑以1.0g/l-50.0g/l、更較佳1.0- 20.0g/l的濃度施加到纖維素纖維。
在本發明的較佳實施方案中(見圖1)，水溶液通過浸軋法或浸染法施加到纖維。適用於這些施加方法的裝置原則上在紡織工業中是眾所周知的。較佳施加方法可以為浸軋-乾燥處理。根據這個實施方案的處理溫度可以在20-40℃之間，較佳在20-30℃之間。浸軋方法可在以乾燥纖維計算30-100重量%之間、較佳50-90重量%之間的軋液率操作。
在本發明的另一個較佳實施方案(見圖2)中，步驟a.的水溶液進一步包含漂白劑(較佳還原漂白劑)和酸穩定的螢光增白劑。這個實施方案通常可以與常規漂白步驟相同的方式和用與常規漂白步驟相同的設備進行，例如在適合漂白纖維或紡織物的容器、槽或其它裝置中。對於本發明的這個實施方案，合適的纖維：液體比可以為1:3至1:50(重量)，較佳1:4至1:20(重量)。合適的溫度可以在20至95℃的範圍內，較佳80至90℃。處理的持續時間可以在15-90分鐘之間，較佳在30-60分鐘之間。
在本發明的還另一個較佳實施方案中(見圖3)，在上述方法(即，根據圖2使用漂白劑和酸穩定的螢光增白劑)的步驟b.和步驟c.之間，在附加步驟d.中，通過浸軋法或浸染法，用pH控制在4.0-7.0之間且包含保護劑的水溶液處理纖維。隨後在步驟c.之前將纖維乾燥。根據本發明的這個實施方案，對於步驟b.，本發明的這個實施方案的合適纖維:液體比可以為1:3至1:50(重量)，較佳1:4至1:20(重量)。步驟b.中合適的溫度可在20至95℃範圍內，較佳80至90℃。步驟b.中處理的持續時間可在15-90分鐘之間，較佳在30-60分鐘之間。對於步驟d.，較佳浸軋-乾燥處理，處理溫度可在20-40℃之間，較佳在20和-30℃之間。步驟d.的浸軋方法可在以乾燥纖維計算30-100重量%之間、較佳50-90重量%之間的軋液率操作。
還原漂白劑通常為本領域的技術人員已知。例如，根據本發明，可用連二亞硫酸鈉(也稱為sodium dithionate或“Hydros”)作為還原漂白劑。根據本發明的還原漂白劑可以0.5-4.0重量%之間、較佳1.0-3.0重量%之間的濃度施加。
本文所述根據本發明的增白劑可以為螢光增白劑，例如氧化性、基於茋的螢光增白劑。較佳可對酸穩定。合適的試劑可以商品名Uvitex BHA liq,購得(來自Huntsman/
U.S.A)。較佳增白劑可以0.5-4.0重量%之間、較佳1.0-3.0重量%之間的濃度施加。
在上述本發明的較佳實施方案中，纖維素纖維在步驟a.之前漂白-見圖3中的可選的步驟。此漂白可例如在氧化條件下以例如1:10(重量：重量)的纖維:液體比在鹼性溶液中進行，該鹼性溶液例如包含0.1-12.0g/l之間、較佳在0.5 -3.0g/l之間NaOH(薄片)(用於施加到人造纖維素纖維)和1.0 -12.0ml/l之間、較佳在2.0-6.0ml/l之間過氧化氫(50%)(用於施加到人造纖維素纖維)的溶液。
在根據本發明的方法中，纖維素纖維可以為選自以下群組的一種或多種：天然纖維素纖維，例如棉、麻和木棉；和人造纖維素纖維，例如黏膠、莫代爾、萊塞爾、銅氨纖維、富纖、二醋酸纖維素和三醋酸纖維素纖維。
纖維較佳以短纖維、長絲、紗或紡織或針織織物、服裝或其它紡織物品(包括內衣、胸罩和在其製造期間需要高溫處理的任何其它服裝和紡織物品)的形式被處理。
令人驚訝的是，根據本發明的方法能夠改善隨後經受高溫過程的纖維素纖維或再生纖維及其共混物上的螢光增白劑(螢光增亮劑)的白度。根據本發明的方法還允許將天然纖維素纖維、再生纖維素纖維和/或它們的共混物染色成淺淡和/或亮色，這經受高溫過程無需再次漂白。此外，與根據現有技術水準在高溫條件處理後需要纖維素纖維或再生纖維及其共混物的再漂白相比，根據本發明的方法節省了時間、水和其它資源。
現在用實施例說明本發明。這些實施例不以任何方式限制本發明的範圍。本發明還包括基於相同發明概念的任何其它實施方案。
實施例所有實施例均對由94%莫代爾EcoClean纖維/6%斯潘德克斯20D纖維在單面針織結構中組成的織物進行。
根據AATCC TM110 2e標準，將白度確定為CIE白度指數方法。白度數值越高，白度越好。在測量CIE白度指數(W10)時，儀器必須設置為照明/觀察者組合D65/10°(根據ASTM E313-98)。
實施例 1( 比較實施例 ) ：酸性處理用自來水(pH~7)或稀乙酸(pH 4-5)浸軋織物(見表1)，然後在100℃乾燥90秒。軋液率總是為約78%(重量/重量，相對於乾燥織物重量)。隨後，將織物送至表1中列出的溫度熱定型120秒。
表1顯示，如果溫度能保持在約180℃，則無論pH如何，變黃都是可以接受的。如果需要更高溫度，則pH應保持在中等酸性值，約pH 4至5，以實現更好的白度。
實施例 2 ：用保護劑浸軋用pH 7另外包含0.5g/l保護劑TP 1740(來自
Brueggemann Chemical/Germany)的溶液浸軋織物，且軋液率為78%。然後在100℃乾燥60秒，並送至200℃溫度熱定型120秒。
實施例 3 ：耐高溫處理的螢光增白製品首先，將織物在90℃在包含1g/l NaOH(薄片)和4ml/l過氧化氫(50%)的溶液中以液體/織物比1/10(重量/重量)漂白30分鐘。隨後，使該織物在90℃在包含3g/l連二亞硫酸鈉、0.85重量% Uvitex BHA liq(來自Huntsman/USA的酸穩定螢光增白劑)、3g/l芒硝和一定量「X」(g/l)TP1740 (「X」參見表3)的溶液中以液體/織物比1/10(重量/重量)增白30分鐘。用過氧化氫漂白織物，隨後同時還原漂白和增白。根據以上配方處理織物。在實施例3.b中，增白浴另外包含2g/l保護劑TP 1740(來自Brueggemann Chemical/
Germany)，並送至180℃熱定型120秒。
表3顯示加入保護劑TP1740進一步減輕變黃，並引起熱定型後白度的改善。
實施例 4 ：用保護劑和螢光增白劑中性洗滌，然後用保護劑浸軋 - 乾燥以與實施例3相同的方式漂白織物。隨後，使織物在90℃在包含3g/l連二亞硫酸鈉、0.85重量% Uvitex BHA liq (來自Huntsman/USA)、3g/l芒硝和8g/l保護劑TP 1740(來自Brueggemann Chemical/Germany)的溶液中增白30分鐘。隨後在pH 6洗滌織物，並通過浸軋-乾燥施加另外的8g/l保護劑TP1740。最後，將織物送至180℃熱定型120s。所得織物最終顯示灰度/顏色變化值為5。這種處理在升高的溫度下熱處理(如熱定型)期間在防止纖維素纖維變黃方面表現出最高的性能。
實施例 5 ：用保護劑浸軋，隨後浸軋 - 熱溶這個實施例應模擬聚酯連續染色過程期間發生的條件，其中處理的織物包含聚酯纖維與人造纖維素纖維的共混物。用2g/l保護劑TP1740在pH 6處理織物，並照常乾燥。隨後，通過分別在210℃與220℃熱溶60秒處理所得織物(見表4，實施例5.b和5.d)。為了比較，使相同的織物，但未用保護劑處理，在相同的條件下熱溶(參見表4，實施例5.a和5.c)。結果顯示，保護劑在這樣的高溫下減輕纖維素纖維的變黃。作為根據本發明的方法的另外的優點，對分散染料沒有影響或影響最小。
According to the invention, protecting agents comprise alkaline earth metal and zinc salts of hydroxy(substituted)alkanoic acids and oxoalkanoic acids. The alkaline earth metal is preferably magnesium. A suitable protectant is eg TP1740, commercially available from Brueggemann Chemical, Germany. The protecting agent may preferably be applied to the cellulosic fibers at a concentration of 1.0 g/l to 50.0 g/l, more preferably 1.0 to 20.0 g/l. In a preferred embodiment of the invention (see Figure 1), the aqueous solution is applied to the fibers by padding or exhaust dyeing. Apparatus suitable for these application methods are in principle well known in the textile industry. A preferred method of application may be a pad-dry process. The treatment temperature according to this embodiment may be between 20-40°C, preferably between 20-30°C. The padding method can be operated at a squeeze rate of 30-100% by weight, preferably 50-90% by weight, based on dry fibers. In another preferred embodiment of the present invention (see Figure 2), the aqueous solution of step a. further comprises a bleaching agent (preferably a reducing bleaching agent) and an acid-stable fluorescent whitening agent. This embodiment can generally be carried out in the same manner and with the same equipment as conventional bleaching steps, for example in vessels, tanks or other apparatus suitable for bleaching fibers or textiles. Suitable fiber:liquid ratios for this embodiment of the invention may be 1:3 to 1:50 by weight, preferably 1:4 to 1:20 by weight. A suitable temperature may be in the range of 20 to 95°C, preferably 80 to 90°C. The duration of the treatment may be between 15-90 minutes, preferably between 30-60 minutes. In yet another preferred embodiment of the present invention (see Figure 3), between step b. and step c. , in an additional step d., the fibers are treated with an aqueous solution containing a protective agent with a pH controlled between 4.0 and 7.0 by padding or exhaust dyeing. The fibers are then dried prior to step c. According to this embodiment of the invention, for step b. a suitable fiber:liquid ratio of this embodiment of the invention may be 1:3 to 1:50 by weight, preferably 1:4 to 1:20 by weight . A suitable temperature in step b. may be in the range of 20 to 95°C, preferably 80 to 90°C. The duration of the treatment in step b. may be between 15-90 minutes, preferably between 30-60 minutes. For step d., preferably a pad-drying treatment, the treatment temperature may be between 20-40°C, preferably between 20 and -30°C. The padding method in step d. can be operated at a squeeze rate of 30-100% by weight, preferably 50-90% by weight, based on dry fibers. Reducing bleaches are generally known to those skilled in the art. For example, sodium dithionite (also known as sodium dithionate or "Hydros") may be used as a reducing bleach in accordance with the present invention. The reducing bleaches according to the invention may be applied in concentrations of between 0.5-4.0% by weight, preferably between 1.0-3.0% by weight. The brighteners according to the invention described herein may be fluorescent whitening agents, for example oxidative, stilbene-based fluorescent whitening agents. Preferably it is acid stable. A suitable reagent is commercially available under the trade name Uvitex BHA liq, (ex Huntsman/USA). Preferably the brightener may be applied at a concentration between 0.5-4.0 wt%, preferably between 1.0-3.0 wt%. In the preferred embodiments of the invention described above, the cellulosic fibers are bleached prior to step a. - see optional step in FIG. 3 . This bleaching can be carried out, for example, under oxidative conditions at a fiber:liquid ratio of, for example, 1:10 (weight:weight) in an alkaline solution comprising, for example, between 0.1-12.0 g/l, preferably between 0.5- Between 3.0 g/l NaOH (flakes) (for application to man-made cellulose fibers) and between 1.0-12.0 ml/l, preferably between 2.0-6.0 ml/l hydrogen peroxide (50%) (with for application to man-made cellulose fibers). In the method according to the present invention, the cellulose fibers may be one or more selected from the following groups: natural cellulose fibers such as cotton, hemp and kapok; and man-made cellulose fibers such as viscose, modal, lyocell, Cupro, rich fiber, cellulose diacetate and cellulose triacetate. Fibers are preferably processed in the form of staple fibers, filaments, yarns or woven or knitted fabrics, garments or other textile items including underwear, bras and any other garments and textile items that require high temperature treatment during their manufacture. Surprisingly, the method according to the invention is able to improve the whiteness of optical brighteners (fluorescent brighteners) on cellulose fibers or regenerated fibers and blends thereof which are subsequently subjected to high temperature processes. The method according to the invention also allows dyeing natural cellulose fibers, regenerated cellulose fibers and/or blends thereof in light and/or bright colours, which are subjected to high temperature processes without further bleaching. Furthermore, the process according to the invention saves time, water and other resources compared to the need for re-bleaching of cellulosic fibers or regenerated fibers and blends thereof after treatment at high temperature conditions according to the state of the art. The present invention will now be illustrated by way of examples. These examples do not limit the scope of the invention in any way. The invention also includes any other embodiments based on the same inventive concept. EXAMPLES All examples were carried out on fabrics consisting of 94% Modal EcoClean fibers/6% Spandex 20D fibers in a single jersey construction. Whiteness is determined as the CIE Whiteness Index method according to AATCC TM110 2e standard. The higher the whiteness value, the better the whiteness. When measuring the CIE Whiteness Index (W10), the instrument must be set to the illuminant/observer combination D65/10° (according to ASTM E313-98). Example 1 ( comparative example ) : Acid treatment The fabric was padded with tap water (pH~7) or dilute acetic acid (pH 4-5) (see Table 1), and then dried at 100° C. for 90 seconds. The squeeze rate was always about 78% (w/w, relative to dry fabric weight). Subsequently, the fabric was sent to the temperature listed in Table 1 for heat setting for 120 seconds. Table 1 shows that yellowing is acceptable regardless of pH if the temperature can be maintained at about 180°C. If higher temperatures are required, the pH should be kept at a moderately acidic value, around pH 4 to 5, for better whiteness. Example 2 : Padding with Protectant A fabric was padded with a solution at pH 7 additionally containing 0.5 g/l of protectant TP 1740 (from Brueggemann Chemical/Germany) with a wet rate of 78%. It was then dried at 100°C for 60 seconds and sent to a temperature of 200°C for heat setting for 120 seconds. Example 3 : Fluorescent whitening products of high temperature resistance treatment At first, the fabric was treated at 90° C. in a solution containing 1 g/l NaOH (flakes) and 4 ml/l hydrogen peroxide (50%) at a liquid/fabric ratio of 1/ 10 (w/w) bleach for 30 minutes. Subsequently, the fabric was subjected to a mixture of 3 g/l sodium dithionite, 0.85% by weight Uvitex BHA liq (an acid-stable optical brightener from Huntsman/USA), 3 g/l Glauber's salt and an amount of "X" (g /1) Whitening in a solution of TP1740 ("X" see Table 3) at a liquor/fabric ratio of 1/10 (wt/wt) for 30 minutes. Bleaching of fabrics with hydrogen peroxide followed by simultaneous reduction bleaching and whitening. Treat fabric according to recipe above. In example 3.b, the whitening bath additionally contained 2 g/l protectant TP 1740 (from Brueggemann Chemical/Germany) and was sent to 180° C. for heat setting for 120 seconds. Table 3 shows that the addition of protective agent TP1740 further reduces yellowing and causes improvement of whiteness after heat setting. Example 4 : Neutral wash with protectant and fluorescent whitening agent, then pad - dry with protectant to bleach the fabric in the same manner as in Example 3. Subsequently, the fabric was exposed to a solution containing 3 g/l sodium dithionite, 0.85% by weight Uvitex BHA liq (from Huntsman/USA), 3 g/l Glauber's salt and 8 g/l protectant TP 1740 (from Brueggemann Chemical/Germany) at 90°C Medium whitening for 30 minutes. The fabric was subsequently washed at pH 6 and an additional 8 g/l of protectant TP1740 was applied by pad-drying. Finally, the fabric was sent to heat setting at 180°C for 120s. The resulting fabric finally exhibited a grayscale/color change value of 5. This treatment exhibits the highest performance in preventing yellowing of cellulosic fibers during heat treatment at elevated temperatures, such as heat setting. Example 5 : Padding with protectant followed by padding - thermosol This example should simulate the conditions occurring during a continuous polyester dyeing process where the treated fabric comprises a blend of polyester fibers with man-made cellulose fibers. The fabric was treated with 2 g/l protectant TP1740 at pH 6 and dried as usual. Subsequently, the resulting fabric was treated by heat melting at 210°C and 220°C for 60 seconds, respectively (see Table 4, Examples 5.b and 5.d). For comparison, the same fabrics, but not treated with protectant, were heat fused under the same conditions (see Table 4, Examples 5.a and 5.c). The results show that the protectant reduces the yellowing of the cellulose fibers at such high temperatures. As a further advantage of the method according to the invention, there is no or minimal influence on the disperse dyes.
