CN1664183A - A kind of regenerated silk fiber using salt solution as coagulation bath and preparation method thereof - Google Patents

Abstract

This invention adopts wet way filature to prepare a high capability rebirth silk fibre method according to raw material used with industry scrap silk. The method take the high chroma rebirth silk protein water liquor (10-40%) with filature former liquor, take the quite high inorganic salt acidity water liquor with curdle liquor. Then get the excellent mechanics capability rebirth silk fibre after wet way filature and extending, heat manage. In this way, rebirth silk fibre have blare of nature silk fibre and excellent synthesis mechanics capability. The rupture intention can get 0.6Gpa and rupture elongate rate can be 30%. This invention has the trait that is abroad raw material source, low cost and simple filature process, green environment protecting.

Description

A kind of regenerated silk fiber using salt solution as coagulation bath and preparation method thereof

technical field

The invention belongs to the technical fields of textile fiber, material science, bionics, and protein chemistry, and specifically relates to a method of using a high-concentration aqueous solution of regenerated silk protein as a spinning stock solution and a relatively high-concentration inorganic hydrochloric acid solution as a coagulation bath. A high-performance regenerated silk fiber obtained from silk and a preparation method thereof.

Background technique

Spider silk has always attracted the research interest of many scientists because of its excellent mechanical properties. Its comprehensive mechanical properties exceed any kind of artificial fiber at present, and it can be applied to fields with special performance requirements such as body armor. But so far, natural spider silk cannot be obtained in large quantities, and because it has broad application prospects in the field of high-performance materials, artificially preparing fiber materials with excellent mechanical properties of spider silk has always been the goal of scientists.

Silk is an excellent natural fiber with the advantages of softness, good air permeability and comfortable wearing. It is widely welcomed by people and widely used. Compared with spider silk, silkworm silk is generally far inferior in mechanical properties to spider silk. It can be seen from the amino acid sequence that the composition and sequence structure of the two are very different, but research shows that silk can have similar mechanical properties to spider silk under certain conditions. The research results published by the inventor on Nature in 2002 showed that under certain spinning conditions, the mechanical properties of silk can reach the level of spider silk, and usually the difference between them mainly comes from the silk spinning process Structural defects formed in. Therefore, how to overcome the defects in the process of silkworm spinning, and how to use rich sources of silk protein to spin artificial fibers with excellent mechanical properties of spider silk has always been a research topic for scientists. If the natural silk protein can be used, artificial spinning method can be used to overcome the inherent defects of silkworms in the silk spinning process, so as to produce regenerated silk fibers with excellent mechanical properties, no matter from the perspective of polymer materials or bionics. Significance. At the same time, using a large amount of waste silk produced in industrial production as raw materials to make spinning stock solution can also greatly reduce the production cost of regenerated silk fibers.

Studies have shown that the silk spinning process of silkworms is to pass the water-soluble protein in the body through the spinning mouth, and form water-insoluble silk fibers under the action of factors such as shear force. The whole silk spinning process is carried out under the condition of normal temperature and water content. When the silk protein advances from the front gland to the middle gland, the water is gradually absorbed, and then passes through the gradually narrowed rear silk gland, and is extruded through the silk-spinning opening to become Water-insoluble silk. It is generally believed that the silk spinning process is a process of conformational transformation of silk protein. Silk protein mostly adopts random coil and/or helical conformation in dilute solution, but it will transform into a water-insoluble β-sheet conformation due to the influence of shear force and dehydration during silk spinning.

The artificial spinning of regenerated silk protein has always been a problem that the chemical fiber field seeks to solve. For example, DuPont invented a spinning method that uses hexafluoroisopropanol (United States Patent: 5252285) as a solvent and alcohol as a coagulation bath; Among the published patents in my country, such as application numbers 95111366.6, 94114071.7, 99116636.1, and 02109229.3, the method for preparing composite fibers with silkworm chrysalis protein, silk protein and synthetic polymers has been reported. But do not see the successful example that useful pure silk protein aqueous solution carries out artificial spinning so far.

The present invention starts from simulating the spinning process of silkworms, uses a high-concentration regenerated silk protein aqueous solution as the spinning stock solution, and uses a relatively high-concentration inorganic hydrochloric acid solution as the coagulation bath. When the spinning stock solution enters the coagulation bath from the spinneret, Water is gradually absorbed, and the concentration of spinning dope increases gradually; after stretching, silk protein transforms into a water-insoluble β-conformation; finally, after steam heat treatment, regenerated silk fibers with excellent properties can be obtained.

Contents of the invention

The object of the present invention is to provide a regenerated silk fiber with good mechanical properties and a preparation method thereof.

The preparation method of the regenerated silk fiber proposed by the present invention is to use the high-concentration regenerated silk protein aqueous solution as the spinning stock solution, use the inorganic hydrochloric acidic aqueous solution as the coagulation bath, and the concentration is 15% to saturation, and use the wet spinning technology and after drawing Stretching and heat treatment.

In the above method, the high-concentration regenerated silk protein solution can be prepared according to the inventor's previous invention patent (patent application number 03142201.2, publication number CN 143866A), and its concentration is 10-40%.

In the above method, the coagulation bath such as inorganic salt is one or more of ammonium sulfate, sodium sulfate, potassium sulfate, zinc sulfate, sodium phosphate and its acid salt, and sodium chloride.

In the above method, the concentration of the inorganic salt solution used as the coagulation bath is 15% to saturation, and the pH value is 2-6.

The operation steps of the above method are as follows: the high-concentration silk protein solution is degassed and left to stand, and then spun with common wet spinning equipment. The residence time of the spinning dope in the inorganic salt coagulation bath at 10-60°C is 2-10 minutes, during which the post-stretching of the formed regenerated silk fiber is carried out 2-8 times. Then wash the spun regenerated silk fiber with water to remove the inorganic salts remaining inside the fiber, then dry it, and finally stretch the dried regenerated silk fiber 1 to 2 times in hot water at 60-100°C, and then Heat treatment with steam at 100-150°C, and dry to obtain the final regenerated silk fiber.

The present invention uses a high-concentration regenerated silk protein aqueous solution as the spinning stock solution. Compared with the spinning stock solution used in other invention patents, the biggest difference is that the organic solvent ( For example, the use of formic acid, hexafluoroisopropanol, etc.) not only effectively controls the degradation of silk protein, but also greatly reduces production costs, and avoids environmental pollution and harm.

The coagulation bath adopted in the present invention is an inorganic salt solution, which has low cost, no pollution and can be recycled. The obtained regenerated silk fiber has the luster of natural silk fiber, has excellent mechanical properties, and has a microstructure similar to natural silk. The breaking strength of the regenerated silk fiber obtained by the invention is 0.1-0.6 GPa, and the breaking elongation is 10%-30%.

Description of drawings

Fig. 1 and Fig. 2 are respectively the scanning electron micrographs of the surface and section of the regenerated silk fiber spun by the present invention.

Detailed ways

Example

The following examples will further describe the invention, but should not be considered as limiting the scope of the invention.

Example 1: use 13% regenerated silk protein aqueous solution as spinning stock solution, use 40% (NH ₄ ) ₂ SO ₄ solution as coagulation bath to carry out wet spinning, and the spinning temperature is 25°C. The obtained regenerated silk fiber is kept in the coagulation bath for 8 minutes and stretched to 4 times the original length, washed with water and then dried. Then continue to stretch 1 time in hot water at 90°C, and then dry it after being treated with water vapor at 120°C. The breaking strength of the obtained regenerated silk fiber is 0.5GPa, and the breaking elongation is 22%.

Example 2: use a 20% regenerated silk protein aqueous solution as the spinning stock solution, use 20% Na _SO solution (adjust the pH to 4.0) as a coagulation bath to carry out _wet spinning, and the spinning temperature is 10°C . The obtained regenerated silk fiber is kept in the coagulation bath for 10 minutes, stretched to 5 times of the original length, washed with water and then dried. Then continue stretching in hot water at 80°C for 1 time, and then dry after steam treatment at 130°C. The fracture strength of the obtained regenerated silk fiber is 0.4GPa, and the elongation at break is 20%.

Example 3: use a regenerated silk protein aqueous solution with a concentration of 30% as the spinning stock solution, use a saturated Zn ₂ SO ₄ solution as a coagulation bath to carry out wet spinning, and the spinning temperature is 40°C. The obtained regenerated silk fiber is kept in the coagulation bath for 5 minutes and stretched to 4 times of the original length, washed with water and then dried. Then continue to stretch twice in hot water at 70°C, and then dry it after being treated with water vapor at 110°C. The breaking strength of the obtained regenerated silk fiber is 0.3GPa, and the breaking elongation is 15%.

Example 4: use a 20% regenerated silk protein aqueous solution as the spinning stock solution, use 30% K ₂ SO ₄ solution (adjust the pH to 3.0) as a coagulation bath to carry out wet spinning, and the spinning temperature is 60°C . The obtained regenerated silk fiber is kept in the coagulation bath for 10 minutes, stretched to 6 times of the original length, washed with water and then dried. Then continue to stretch twice in hot water at 95°C, and then dry it after being treated with water vapor at 140°C. The breaking strength of the obtained regenerated silk fiber is 0.2GPa, and the breaking elongation is 15%.

Example 5: use a 40% regenerated silk protein aqueous solution as the spinning stock solution, use a 35% Na _{PO solution} (adjust the pH to 2.5) as a coagulation bath to carry out wet spinning, and the spinning temperature is 20°C . The obtained regenerated silk fiber is kept in the coagulation bath for 10 minutes, stretched to 4 times of the original length, washed with water and then dried. Then continue stretching in hot water at 100°C for 1 time, and then dry after steam treatment at 150°C. The breaking strength of the obtained regenerated silk fiber is 0.3GPa, and the elongation at break is 25%.

Embodiment 6: use the regenerated silk protein aqueous solution of 15% as the spinning stock solution with a concentration, and use 10% NaCl and 15% Na _{SO The} mixed solution (adjusting pH to 2.5) is used as a coagulation bath to carry out wet spinning, spinning The temperature is 40°C. The obtained regenerated silk fiber is kept in the coagulation bath for 8 minutes and stretched to 4 times the original length, washed with water and then dried. Then continue stretching by 1 time in hot water at 95°C, and then dry after steam treatment at 120°C. The breaking strength of the obtained regenerated silk fiber is 0.5GPa, and the breaking elongation is 30%.

Claims (5)

1. the preparation method of a regenerated silk fiber, it is characterized in that: the regenerated silk protein solution with concentration 10-40% is a spinning solution, carries out wet spinning with the inorganic salts acidic aqueous solution as coagulating bath.

2. preparation method according to claim 1 is characterized in that inorganic salts are one or more of ammonium sulfate, sodium sulphate, potassium sulfate, zinc sulfate, sodium phosphate and acid salt thereof and sodium chloride.

3. require described preparation method according to claim 1, the concentration that it is characterized in that inorganic salt solution is 15% to saturated, and the pH value is 2 ~ 6.

4. preparation method according to claim 1 is characterized in that spinning solution 2 ~ 10 minutes time of staying in 10-60 ℃ coagulating bath, then formed regenerated silk fiber is carried out 2 ~ 8 times after-drawing, then the oven dry of washing back; In 60 ~ 100 ℃ hot water, stretch 1 ~ 2 times again, use 100 ~ 150 ℃ of water vapours to heat-treat again, and oven dry.

5. regenerated silk fiber that is obtained by the described preparation method of claim 1 ~ 4, it is characterized in that: have the microstructure similar to natural silk, its fracture strength is 0.1 ~ 0.6GPa, and elongation at break is 10% ~ 30%.

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