Abstract:
The invention relates to the fibre assistant field, in particular relates to a process for health preserving bast fibres and a jute fibre specific health preserving assistant used in the same. this invention provides a process of health preserving bast fibres, wherein, comprising the steps of: a. spraying the prepared assistant on bast fibres, wherein, the weight proportion of said assistant and said bast fibres ranges from 0.4:1 to 0.5:1. b. placing the bast fibres processed through step a in a first health preserving container for 2-3 days; c. taking out the bast fibres processed through step b from the first health preserving container, turning over such bast fibres, and placing them in a second health preserving container; then heating such bast fibres upto 50-60 □, after that, storing the heated bast fibres in said second health preserving container for 5-6 days.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to the fibre assistant field, in particular relates to a process for health preserving bast fibres and a jute fibre specific health preserving assistant used in the same. 
       BACKGROUND 
       [0002]    With the rising of human material living standards, more and more people begin to move their attention from the durability of clothing to the comfort of clothing. Due to the good moisture absorption, air permeability, low static and good antibacterial properties of bast fibre, bast fabrics have gained more and more popularity with people. The existing bast fabrics mainly refer to the linen, ramie or the combination obtained through blended spinning or interweaving said materials with other fibres such as cotton, wool, chemical fibres, or silk, etc. However, as linen and ramie are expensive, the bast fabrics are not widely used. Jute fibre is one of the most widely used cellulose fibres and only follows cotton fibre in the world. Jute is cheap in price and has better moisture absorption and drapability than linen and ramie, and its antibacterial ability just follows that of hemp, so that it has great application value and developmental potential. However, the lignin content in jute is quite high (up to 10-13%), which is several times higher than that in linen, and jute fibre is very thick and hard, and with poor spinnability, restraining the use of jute in fabrics. In the existing technology, in order to improve the spinnability of said fibres, the nature fibres must be firstly degummed and thinned However, although the fibres are degummed and thinned, the fibres still remain hard, and are difficult to be spun. Therefore, it is necessary to improve the fibre traits of the bast fibres that are degummed and thinned 
         [0003]    Nowadays, the ordinary process for improving the fibre traits of bast fibres is to health preserving the bast fibres using bast fibre health preserving assistant. Said health preserving means after the bast fibres are processed through degumming and thinning, assistants are used to improve the softness and spinnability of said bast fibres before spinning; said health preserving assistant can selectively contain softener (bast softening agent), emulsifying agent, penetrant or humectant, etc, according to the requirements for the fixed performance of product. It is found from the study that the selections of different assistants and different weight proportion of ingredients in said assistants may cause different effects of improving the spinnability, and moistures of bast fibres. Therefore, in the existing spinning process, it is very important for bast fibre spinning industry to select a good health preserving assistant that is applicable to different bast fibres, and choose the appropriate weight proportion of its ingredients. 
         [0004]    For jute fibres, in the ordinary health preserving assistant, the amino silicone oil is used as the softener. That the amino silicone oil softens and smoothes the fibres is mainly because of the amino within it. In the amino silicone oil, the content of amidogen is defined by ammonia value, which refers to the volume of hydrochloric acid with 1 equivalent concentration in millilitre used for neutralizing 1 gram of amino-silicone oil. In general, the higher content of amidogen is, the higher ammonia value is, and the softer and smoother the processed fibres will be. For the persons having ordinary skills in the art, they usually raise the ammonia value of amino-silicone oil, in order to improve the softness of fabrics, so that the ammonia value is generally above 0.2. However, high ammonia value causes high smoothness of fibres, small cohesive force between two single fibres, and poor spinnability of fibres, thus, generally, the ammonia value selected in the prior art is no more than 0.6. In addition, with the rise of ammonia value of amino-silicone, the possibility of active hydrogen in amidogen being oxidized will rise, and it is prone to be oxidized into chromophore, resulting in the yellowing of the fibres. In order to solve this problem, further bleaching to the fibres will be conducted in the prior at. However, the conduct of bleaching will increase the cost and will generate a lot of waste water. 
         [0005]    In regard to the process for health preserving the bast fibres, Chinese Patent publication number.CN1292435A and CN1086273A disclose a process for health preserving the bast fibres, wherein, firstly the bast fibres are humidified and accumulated stored in the container for 18-30 hours for health preservation, then the health persevered bast fibres are taken out and combined into strips manually; after that, the bast fibre strips are carded. Likewise, Chinese patent No. CN1796622A discloses a process for double modifying the linen second coarse fibres, wherein, in the course of modifying said linen second coarse fibres, said linen second coarse fibres should also be health preserved, and this method is also used for humidifying and health preserving the bast fibres for 36-48 hours in a room with 18-25 □. However, the dampening rate of health preserved bast fibres only reaches 15%-18%. In said prior art, the bast fibres are health preserved through humidification at room temperature, and the duration for such health preservation is within 48 hours. In the above mentioned method, the assistant can not infiltrate inside of the bast fibres due to the room temperature; in addition, it is not able to make the small amount of gum work in the course of health preservation, which is remained after degumming of said bast fibres in the period of pre-treatment. Furthermore, the underlayer of bast fibres in the health preserving container could hardly get in touch with air, relatively to those on the top, restraining the fibres from “breathing”, so as to result in the unclearness between the “cavity” and the “hole” connected to it in the bast fibres, and also the health preserving assistant can not sufficiently infiltrate inside of said bast fibres. Therefore, this may have bad influences on the effect of health preserving bast fibres. 
       SUMMARY OF INVENTION 
       [0006]    One of the objectives of this invention is to solve the problem with spinnability of bast fibres, in particular, low ammonia value of amino silicone oil results in low softness of fibres, and high ammonia value of amino silicone oil yellows the fabrics and cause high smoothness of fibres, so as to deteriorate the cohesive force among fibres and the spinnability of fibres. In order to solve the problems above, a kind of amino silicone oil with appropriate ammonia value should be selected. The invention also provide a jute fibre specific health preserving assistant that makes the jute fibres have good softness, appropriate whiteness, and high spinnability. 
         [0007]    Another objective of this invention is to solve the problem with the insufficiency of health preservation of bast fibres. In order to solve the problems, an improved process of health preserving bast fibres is provided, in particular, the process allows bast fibre health preserving assistant sufficiently enter the inside of bast fibres, ensuring the bast fibres are sufficient health preserved, and further health preserving bast fibres with the gum used in the bast fibre pre-processing stage. 
         [0008]    In order to solve the problems above, this invention provides a process of health preserving bast fibres, wherein, comprising the steps of:
       a. spraying the prepared assistant on bast fibres, wherein, the weight proportion of said assistant and said bast fibres ranges from 0.4 to 0.5;   b. placing the bast fibres processed through step a in a first health preserving container for 2-3 days;   c. taking out the bast fibres processed through step b from the first health preserving container, turning over such bast fibres, and placing them in a second health preserving container; then heating such bast fibres upto 50-60 □, after that, storing the heated bast fibres in said second health preserving container for 5-6 days.       
 
         [0012]    The process of health preserving bast fibres, wherein, the bast fibres processed through step 3 are taken out from the second health preserving container, and placed at room temperature for 2-6 hours. 
         [0013]    The process of health preserving bast fibres, wherein, said bast fibres are hemp fibres or jute fibres. 
         [0014]    A just fibre specific health preserving assistant used, containing 0.5-3 weight portions of emulsifying agent, wherein, further containing 5-7 weight portions of amino-silicone oil, the ammonia value of which ranges from 0.3 to 0.4 and the molecular weight ranges from 300 to 30000. 
         [0015]    The above mentioned assistant, wherein, containing 1-2 weight portions of said emulsifying agent and 6 weight portions of said amino-silicone oil. 
         [0016]    The above mentioned assistant, wherein, the ammonia value of said amino-silicone oil is 0.35. 
         [0017]    The above mentioned assistant, wherein, said emulsifying agent is non-ionic emulsifying agent. 
         [0018]    The above mentioned assistant, wherein, said assistant further contains 0.5-3 weight portions of moisturizing agent and 0.5-4 weight portions of hygroscopic agent. 
         [0019]    The above mentioned assistant, wherein, said assistant further contains 0.5-3 weight portions of non-ionic penetrating agent. 
         [0020]    The above mentioned assistant, wherein, containing 0.8-2 weight portions of said moisturizing agent. 
         [0021]    The above mentioned assistant, wherein, containing 1-3 weight portions of said hygroscopic agent. 
         [0022]    The above mentioned assistant, wherein, further containing 5-7 weight portions of quaternary ammonium salt type softening agent. 
         [0023]    The above mentioned assistant, wherein, the weight proportion of said moisturizing agent and said hygroscopic agent ranges from 2:3 to 4:5. 
         [0024]    The above mentioned assistant, wherein, said moisturizing agent is glycerine, and said hygroscopic agent is carbamide. 
         [0025]    The above mentioned assistant, wherein, containing 0.8-2 weight portions of said non-ionic penetrating agent. 
         [0026]    The advantages of this invention are described as bellow:
   (1) The process of health preserving bast fibres is divided into two stages. At the first stage, bast fibres are health preserved under the room temperature for 2-3 days, and this enables the assistant to enter and infiltrate the fibres sufficiently and slowly; as the temperature is room temperature, the assistant is not able to sufficiently reach the core of fibre. Therefore, the health preserving container needs to be heated, and the “cavity” and the “hole” will be further opened with the rising of said container temperature, so that the “passage” in the fibre, which the health preserving assistant moves through, is expanded, thereby facilitating said assistant to reach the core of bast fibres and improving the spinnability of said bast fibres.   (2) When moving the bast fibres from the first health preserving container to the second health preserving container, the bast fibres are turned over. The underlayer of the bast fibres in the first health preserving container come to the top of said bast fibres when they are placed in the second health preserving container. Then, the previous underlayer of said bast fibres can sufficient contact the air, enables the “cavity” in the centre of said bast fibre to sufficiently “breathe”, thereby allowing the health preserving assistant sufficiently enter the “cavity” and the “hole” in said bast fibres for further health preserving.   (3) At the second stage of the process of health preservation, the second health preserving container is heated up to 50-60° C. On the one hand, the gum that remains after the pre-treatment of said bast fibres through degumming, can be reactivated. It can hydrolyze the gum in the bast fibres that are not sufficiently degummed, so as to further separate the bast fibres, and improve the bulkiness of such bast fibres; on the other hand, the “cavity” and the “hole” of the bast fibre can be enlarged once said bast fibres are heated, and this will help the assistant and water infiltrate the inside of the bast fibres.   (4) Naturally placing the bast fibres that are health preserved can enable the water attached to the surface of the bast fibres due to the high temperature during the process of health preservation, to evaporate. This can avoid too much water on the surfaces of the bast fibres, so as to avoid the bast fibres of twisting with the rollers of machine during the process of spinning, thereby improving the efficiency and quality of spinning   (5) In the jute fibre specific health preserving assistant of this invention, on the one hand, the ammonia value of amino-silicone oil ranges from 0.3 to 0.4, and the molecular weight of said amino-silicone oil is small, and the weight proportion of ingredients of the assistant is well controlled. As the amino-silicone oil with small molecular weight can effectively enter the inside of fibres, so as to effectively improve the softness of the jute fibres, and ensure the appropriate smoothness of the surface of the jute fibres and the necessary cohesive force among the jute fibres, thereby improving the spinnability of fibres; on the other hand, the assistant and the weight proportion of ingredients in such assistant used can provide appropriate amino-silicone oil to the fibres, which can make the fibres with the softness required, and will not enhance the possibility of being oxidized due to overload of such amino-silicone oil, so as to effectively avoid yellowing of the jute fibres and ensure the whiteness of them.   (6) In this invention, penetrating agent is added to the jute fibre specific health preserving assistant, and this enables the amino-silicone oil emulsified to effectively and quickly penetrate the inside of fibres, thereby improving the health preservation of fibres.   (7) In this invention, both of hygroscopic agent and moisturizing agent are added to the jute fibre specific health preserving assistant, wherein, said moisturizing agent can effectively retain the water in the fibres, but loss of water in the fibres may be caused during the process of weaving; hygroscopic agent can duly absorb and supply water from outside to the fibres. The moisture balance between internal and external part of fibres can be ensured and the moisture regain of fibres required during the process of weaving jute fibres are kept through well keeping the weight proportion of hygroscopic agent and moisturizing agent.   (8) In this invention, quaternary ammonium salt type softening agent added to the jute fibre specific health preserving assistant can further improve the softness of the fibres that are health preserved with amino-silicone oil.   
 
     
    
     DETAILED DESCRIPTION OF INVENTION 
       [0035]    The principles of health preserving jute fibres with the jute fibre specific health preserving assistant in this invention are as bellows:
   the amino-group in the amino-silicone oil is basic group, said basic group can transform to cation ammonium salt group in the help of acid; the followings are the characteristics of the amino-silicone oil:   (1) Being prone to be emulsified by surfactant.   (2) Improving the softness of said amino-silicone oil.   (3) Enhancing the cohesiveness among fibres.   
 
         [0040]    After that, the the amino-silicone oil are emulsified by the emulsifying agent in the health preserving assistant, thereby ensuring the stability of the health preserving assistant solution. The surface tension of the amino-silicone oil becomes very small, after the amino-silicone oil forms emulsion, and it also become very easy to spread out on the surface of the fibres; if the molecular weight is small, the amino-silicone oil will further reach the core of the fibres; As the amino-group in the amino-silicone oil has strong polarity, it will interact with the carboxyl group and hydroxyl group, forming a solid orientation and absorption on the surface and in the inside of the fibres, meanwhile, the Si—O main strain is formed and has excellence suppleness, The silicon atom in methyl group reduces the friction among fibres, allowing the fibres to have good smoothness and softness, and also making the fibres bulge. In this invention, a majority of the amino-silicone oil emulsified reaches the core of fibres, while a minority of it forms a membrane on the surface of fibres, through selecting an appropriate ammonia value of the amino-silicone oil and weight portion of the ingredients of the assistant. This may improve the softness of jute fibres, and will not reduce the cohesive force among fibres due to high smoothness of the surfaces of fibres caused by the overload of said amino-silicone oil, thereby not affecting the spinnability of the fibres. In addition penetrating agent in the health preserving assistant allows the active ingredients to enter the fibres, so as to enable much less time of health preserving jute fibres than using the health preserving assistant without penetrating agent. The health preserving assistant used in this invention can effectively improve the softness, smoothness and spinnability of jute fibres. 
         [0041]    Further more, another jute fibre specific health preserving assistant creatively adopts both of hygroscopic agent and moisturizing agent as the ingredients of the health preserving assistant; said moisturizing agent effectively retain the water in the fibres. However, the water in the fibres may to some extent lose, but the hygroscopic agent may duly absorb water into the fibres, thereby ensuring the moisture balance of the fibres. The health preserving assistant used can effectively enhance the cohesive force among fibres, and improve the softness and spinnability of fibres. 
         [0042]    Said emulsifying agent is the non-ionic surfactant, the anionic surfactant or the combination of both of them. Wherein, the non-ionic surfactant is preferred, because it does not react with the cation amino-silicone oil, thereby not affecting the health preservation of fibres. 
         [0043]    The penetrating agent is the non ion type penetrating agent. It is selected because the non ion type penetrating agent does not react with the positive ion type amino-silicone oil, thereby not affecting the health preservation of fibres. 
         [0044]    The quaternary ammonium salt type softening agent can also be added to said health preserving assistant, in order to further health preserving the fibres, thereby improving the softness of said fibres. 
         [0045]    The portion mentioned bellow refers to weight portion. 
       EXAMPLE 1 
       [0046]    The ingredients of the jute fibre specific health preserving assistant in this invention are indicated in weight portion as bellow:
   Amino-silicone oil with ammonia value of 0.35 and molecular weight of 300-500: 6 portions;   Double-alkyl dimethyl quaternary ammonium salt 6 portions;   Peregal O (emulsifying agent) 2 portions;   JFC 0.8 portion;   
 
         [0051]    In this example, the amino-silicone oil with ammonia value of 0.35 and molecular weight of 300-500 is selected. Because the molecular weight of said amino-silicone oil is very small, it can easily enter the fibres, and can effectively improve the suppleness of the fibres. The softness of fibres can be improved by double-alkyl dimethyl quaternary ammonium salt, the fibres can be emulsified by peregal O, and JFC as a kind of penetrating agent can accelerate the entry of softening agent into the fibres. The use of abovementioned agents can be very cost effective; wherein, said peragal O is non-ionic emulsifying agent, and is also called peregal oil; it is the condensation compound of epoxyethane and higher fatty alcohol. Said emulsifying agent is not able to combine with fibres, and is very easy to be washed away. 
         [0052]    In addition, the health preserving assistant with above mentioned portions can effectively improve the suppleness, and keep the smoothness and the whiteness of jute fibres, accelerate the entry of the health preserving assistant into the fibres, and enhance the efficiency of health preserving said fibres. 
       EXAMPLE 2 
       [0053]    The ingredients of the jute fibre specific health preserving assistant in this invention are indicated in weight portion as bellow:
   Amino-silicone oil with ammonia value of 0.35 and molecular weight of 1000-5000: 5 portions;   Peregal O (Emulsifying Agent) 1 portion;   Sulfonated Oil (STO) 0.8 portion;   
 
         [0057]    In addition, the health preserving assistant with above mentioned weight portion can effectively improve the suppleness, and keep the smoothness and the whiteness of jute fibres, accelerate the entry of the health preserving assistant into the fibres, and enhance the efficiency of health preserving said fibres. 
       EXAMPLE 3 
       [0058]    The ingredients of the jute fibre specific health preserving assistant in this invention are indicated in weight portion as bellow:
   Amino-silicone oil with ammonia value of 0.35 and molecular weight of 1000-5000: 7 portions;   Peregal O (Emulsifying Agent) 3 portions;   Sulfonated Oil (STO) 2 portions;   
 
         [0062]    In addition, the health preserving assistant with above mentioned weight portion can effectively improve the suppleness, and keep the smoothness and the whiteness of jute fibres, accelerate the entry of the health preserving assistant into the fibres, and enhance the efficiency of health preserving said fibres. 
       EXAMPLE 4 
       [0063]    The ingredients of the jute fibre specific health preserving assistant in this invention are indicated in weight portion as bellow:
   Amino-silicone oil with ammonia value of 0.3 and molecular weight of 10000-15000: 4 portions;   Emulsifying Agent(OP) 0.5 portion;   Neutral RP-98 3 portions;   
 
         [0067]    In this example, the amino-silicone oil with ammonia value of 0.3 and molecular weight of 1000-15000 is selected. Because the molecular weight of said amino-silicone oil is very small, it can easily enter the fibres, and can effectively improve the suppleness of the fibres. The fibres can be emulsified by emulsifying agent (OP), and neutral RP-98 can accelerate the entry of softening agent into the fibres. The use of abovementioned agents can be very cost effective; wherein, said emulsifying agent (OP) is a non-ionic emulsifying agent; it is the condensation compound of epoxyethane and alkylphenol. The health preserving assistant with above mentioned weight portion can effectively improve the suppleness, and keep the smoothness and the whiteness of jute fibres, accelerate the entry of the health preserving assistant into the fibres, and enhance the efficiency of health preserving said fibres. 
         [0068]    All the said JFC, said sulfonated Oil (STO), and said neutral RP-98 are the product names, and these products can be purchased in the market. 
       EXAMPLE 5 
       [0069]    The ingredients of the jute fibre specific health preserving assistant in this invention are indicated in weight portion as bellow:
   Amino-silicone oil with ammonia value of 0.35 and molecular weight of 300-500: 6 portions;   Double-alkyl dimethyl quaternary ammonium salt 6 portions;   Peregal O (emulsifying agent) 2 portions;   Carbamide (hygroscopic agent) 3 portions;   Glycerine (Moisturizing agent) 2 portions;   
 
         [0075]    In this example, the amino-silicone oil with ammonia value of 0.35 and molecular weight of 300-500 is selected. Because the molecular weight of said amino-silicone oil is very small, it can easily enter the fibres, and can effectively improve the suppleness of the fibres. The softness of fibres can be improved by double-alkyl dimethyl quaternary ammonium salt, the fibres can be emulsified by peregal O, and carbamide as a kind of hygroscopic agent can keep the moisture of said fibres, and glycerine as a moisturizing agent has the moisture absorbing ability. The use of abovementioned agents can be very cost effective; wherein, said peragal O is non-ionic emulsifying agent, and is also called peregal oil; it is the condensation compound of epoxyethane and higher fatty alcohol. Said emulsifying agent is not able to combine with fibres, and is very easy to be washed away. 
         [0076]    In addition, the health preserving assistant with above mentioned weight portion can effectively improve the suppleness, and keep the smoothness and the whiteness of jute fibres; in addition, the weight proportion of carbamide and glycerine is 2:3 which is one of preferred embodiments, and can obtain an appropriate moisture regain of jute fibres. 
       EXAMPLE 6 
       [0077]    The ingredients of the jute fibre specific health preserving assistant in this invention are indicated in weight portion as bellow:
   Amino-silicone oil with ammonia value of 0.3 and molecular weight of 1000-3000: 4 portions;   Peregal O (emulsifying agent) 0.5 portion;   Carbamide (hygroscopic agent) 0.5 portion;   Glycerine (Moisturizing agent) 0.5 portion;   
 
         [0082]    The health preserving assistant with above mentioned weight portion can effectively improve the suppleness, and keep the smoothness and the whiteness of jute fibres, and can obtain an appropriate moisture regain. 
       EXAMPLE 7 
       [0083]    The ingredients of the jute fibre specific health preserving assistant in this invention are indicated in weight portion as bellow:
   Amino-silicone oil with ammonia value of 0.4 and molecular weight of 10000-15000: 8 portions;   Emulsifying Agent (OP) 3 portions;   Carbamide (hygroscopic agent) 4 portion;   Glycerine (Moisturizing agent) 3 portion;   
 
         [0088]    In this example, the amino-silicone oil with ammonia value of 0.4 and molecular weight of 10000-15000 is selected. Because the molecular weight of said amino-silicone oil is very small, it can easily enter the fibres, effectively improving the suppleness of the fibres. Wherein, the fibres can be emulsified by emulsifying agent (OP), carbamide as a hygroscopic agent can keep the moisture of said fibres, and glycerine as a moisturizing agent has the moisture absorbing ability. The use of abovementioned agents can be very cost effective; wherein, said emulsifying agent (OP) is non-ionic emulsifying agent; it is the condensation compound of epoxyethane and alkylphenol. The health preserving assistant with above mentioned weight portion can effectively improve the suppleness, and keep the smoothness and the whiteness of jute fibres; in addition, the weight proportion of carbamide and glycerine is 3:4 which is also one of the preferred embodiments, and can obtain an appropriate moisture regain of jute fibres. 
       EXAMPLE 8 
       [0089]    The ingredients of the jute fibre specific health preserving assistant in this invention are indicated in weight portion as bellow:
   Amino-silicone oil with ammonia value of 0.3 and molecular weight of 10000-15000: 8 portions;   Emulsifying Agent (OP) 1.5 portions;   Carbamide (hygroscopic agent) 1 portion;   Glycerine (Moisturizing agent) 0.8 portion;   
 
         [0094]    In this example, the amino-silicone oil with ammonia value of 0.3 and molecular weight of 10000-15000 is selected. Because the molecular weight of said amino-silicone oil is very small, it can easily enter the fibres, effectively improving the suppleness of the fibres. Wherein, the fibres can be emulsified by emulsifying agent (OP), carbamide as a hygroscopic agent can keep the moisture of said fibres, and glycerine as a moisturizing agent has the moisture absorbing ability. The use of abovementioned agents can be very cost effective; wherein, said emulsifying agent (OP) is non-ionic emulsifying agent; it is the condensation compound of epoxyethane and alkylphenol. The health preserving assistant with above mentioned weight portion can effectively improve the suppleness, and keep the smoothness and the whiteness of jute fibres; in addition, the weight proportion of carbamide and glycerine is 4:5 which is also one of the preferred embodiments, and can obtain an appropriate moisture regain of jute fibres. The molecular weight of above mentioned amino-silicone oil can also be 13000-15000, 15000-18000, or 18000-20000. Said amino-silicone oil also can effectively improve the suppleness, and keep the smoothness and the whiteness of jute fibres; the most important thing is that it can obtain an appropriate moisture regain of jute fibres. 
       EXAMPLE 9 
       [0095]    The health preserving assistant after adding water is sprayed on jute fibres, wherein, the weight proportion of said health preserving assistant and water is 1:30. In one of the preferred embodiments, during the process of spraying, said health preserving assistant is sprayed on each layer of the jute fibres paved, until finishing the paving of sufficient said jute fibres to be stored in the health preserving container; wherein, the weight proportion of said health preserving assistant and said jute fibres is 0.4:1, thereby providing sufficient said health preserving assistant to said jute fibres for health preserving. 
         [0096]    Then, the paved jute fibres are placed in a first health preserving container for 2 days. At this stage, said health preserving assistant is ensured to slowly penetrate the fibres. 
         [0097]    After that, the jute fibres are removed out of the first health preserving container, and turned over before being placed in a second health preserving container. This can ensure the underlayer of said jute fibres in the first health preserving container to come to the top when said jute fibres are placed in the second health preserving container. Then, said jute fibres are heated to 60 □. After that, heating is stopped, and the heated jute fibres are health preserved for 5 days. (1) When moving the bast fibres from the first health preserving container to the second health preserving container, the bast fibres are turned over. The previous underlayer of the bast fibres in the first health preserving container come to the top of said bast fibres when they are placed in the second health preserving container. Then, the previous underlayer of said bast fibres can sufficient contact the air, enables the “cavity” in the centre of said bast fibre to sufficiently “breathe”, thereby allowing the health preserving assistant sufficiently enter the “cavity” and the “hole” in said bast fibres for further health preserving. (2) The health preserving container is heated, and the “cavity” and the “hole” of said bast fires will be further enlarged with the rising of said container temperature, so that the “passage” in the fibre, which the health preserving assistant moves through, is expanded, thereby facilitating said health preserving assistant to reach the core of bast fibres and improving the spinnability of said bast fibres. (3) The second health preserving container is heated up to 50-60° C., so that the gum remaining after the pre-treatment of said bast fibres through degumming, can be reactivated. It can hydrolyze the gum in the bast fibres that are not sufficiently degummed, so as to further separate the bast fibres, and improve the bulkiness of such bast fibres. 
         [0098]    The bast fibres health preserved are removed out of the second health preserving container, and placed at room temperature for 6 hours. The placement of said bast fibres at room temperature at this stage can be a very important step. It enables the water attached to the surfaces of said bast fibres due to the high temperature during the process of health preservation, to evaporate, so that it can avoid too much water on the surfaces of the bast fibres, so as to avoid the bast fibres of twisting with the rollers of machine during the process of spinning, thereby improving the efficiency and quality of spinning As an optional step, it can be skipped. However, in the preferred embodiment of health preserving bast fibres, placement of bast fibres at room temperature had better be adopted. 
       EXAMPLE 10 
       [0099]    The health preserving assistant after adding water is sprayed on jute fibres, wherein, the weight proportion of said health preserving assistant and water is 1:30. In one of the preferred embodiments, during the process of spraying, said health preserving assistant is sprayed on each layer of the jute fibres paved, until finishing the paving of sufficient said jute fibres to be stored in the health preserving container; wherein, the weight proportion of said health preserving assistant and said jute fibres is 0.4:1, thereby providing sufficient said health preserving assistant to said jute fibres for health preserving. 
         [0100]    Then, the paved jute fibres are placed in a first health preserving container for 2.5 days. At this stage, said health preserving assistant is ensured to slowly penetrate the fibres. 
         [0101]    After that, the jute fibres are removed out of the first health preserving container, and turned over before being placed in a second health preserving container. Then, said jute fibres are heated to 55° C. After that, heating is stopped, and the heated jute fibres are health preserved for 5.5 days. Heating the bast fibres enables the “cavity” and the “hole” of said bast fibres will be further enlarged with the rising of said container temperature, so that the “passage” in the fibre, which the health preserving assistant moves through, is expanded, thereby facilitating said health preserving assistant to reach the core of bast fibres. In addition, at this temperature, the gum remaining after the pre-treating said bast fibres through degumming, can be reactivated. It can hydrolyze the gum in the bast fibres that are not sufficiently degummed, so as to further separate the bast fibres, and improve the bulkiness of such bast fibres. 
         [0102]    Finally, the bast fibres are removed out of the second health preserving container, and placed at room temperature for 5 hours. 
       EXAMPLE 11 
       [0103]    The health preserving assistant after adding water is sprayed on jute fibres, wherein, the weight proportion of said health preserving assistant and water is 1:60. In one of the preferred embodiments, during the process of spraying, said health preserving assistant is sprayed on each layer of the jute fibres paved, until finishing the paving of sufficient said jute fibres to be stored in the health preserving container; wherein, the weight proportion of said health preserving assistant and said jute fibres is 0.5:1, thereby providing sufficient said health preserving assistant to said jute fibres for health preserving. 
         [0104]    Then, the paved jute fibres are placed in a first health preserving container for 3 days, providing enough time for said health preserving assistant to sufficiently and slowly penetrate the fibres. 
         [0105]    After that, the jute fibres are removed out of the first health preserving container, and turned over before being placed in a second health preserving container. Then, said jute fibres are heated to 50 □. After that, heating is stopped, and the heated jute fibres are health preserved for 6 days. Heating the bast fibres at this stage enables the “cavity” and the “hole” of said bast fibres will be further enlarged with the rising of said container temperature, so that the “passage” in the fibre, which the health preserving assistant moves through, is expanded, thereby facilitating said health preserving assistant to reach the core of bast fibres. In addition, at this temperature, the gum remaining after the pre-treating said bast fibres through degumming, can be reactivated. It can hydrolyze the gum in the bast fibres that are not sufficiently degummed, so as to further separate the bast fibres, and improve the bulkiness of such bast fibres. 
         [0106]    Finally, the bast fibres are removed out of the second health preserving container, and placed at room temperature for 2 hours. 
         [0107]    It is found from the above processes of health preserving bast fibres that the moisture regain of bast fibres before health preservation ranges from 12%-16%, while the moisture regain of bast fibres after health preservation ranges from 32%-38%. Therefore, the processes of health preserving bast fibres can effectively improve the moisture regain of bast fibres, thereby improving the spinnability of the bast fibres. 
         [0108]    In the example 9-11, the weight proportion of health preserving assistant and water are 1:30, 1:45, and 1:60 respectively. However, in the practice, the weight proportion ranging from 1:30 to 1:60 can help achieve the objective of this invention, and should be covered by this invention.