CN101613952B - Finishing oil for manufacturing of continuous silicone carbide fiber and application process thereof - Google Patents

Abstract

An oil agent for continuous silicon carbide fiber production and its application process. The oil agent for continuous silicon carbide fiber manufacture is a modified silicone oil aqueous solution or emulsion prepared by adding water to a modified silicone oil. The modified silicone oil contains different Reactive group polysiloxane. The preparation method of the oil agent of the present invention is simple. Applying the oil agent of the present invention to continuous silicon carbide fiber manufacturing has the characteristics of simple process, convenient operation, and easy implementation on the SiC fiber production line, etc., which can effectively reduce the mechanical damage of PCS fibers when they pass through the guide rollers, and reduce the hairiness of the fibers. , Broken end, improve the fiber bundle and bundle strength, improve the mechanical properties and uniformity of the SiC fiber prepared.

Description

Continuous silicon carbide fiber manufacturing oil and its application process

technical field

The invention relates to an oil agent for continuous silicon carbide fiber manufacture and its application process.

Background technique

Silicon carbide fibers have important application values in high-tech fields such as aviation, aerospace, nuclear industry, and weaponry because of their high strength, high modulus, high temperature resistance, oxidation resistance, and corrosion resistance.

Industrially, the industrial production of continuous SiC fibers has been realized by using the organosilicon polymer polycarbosilane (Polycarbosilane, “PCS”) precursor conversion method. Its typical preparation process is as follows: using polycarbosilane obtained by high-temperature cracking, rearrangement and polycondensation of organosilicon polymers as a precursor, continuous PCS fibers are prepared by melt spinning, and the continuous PCS fibers are placed in air for oxidation reaction. Intermolecular cross-linking becomes non-melting fibers, and then high-temperature firing is carried out under the protection of an inert atmosphere in a high-temperature furnace, and continuous SiC fibers are obtained through thermal decomposition transformation and inorganicization.

Silicon carbide fiber, like carbon fiber, is a brittle material with low tensile strength. In the preparation process, the fibril-PCS fiber obtained by melt spinning will inevitably have multiple contacts with godet rolls, wire drums, etc., and be subjected to high temperature and high speed air flow Washing, it will also react with the reaction atmosphere to exotherm or high-temperature thermal decomposition to produce a large shrinkage, so it is easy to produce various internal and surface defects.

In the production process of carbon fiber, applying suitable oil agent and reasonable oiling process has been proved to be an effective means to prevent surface defects of fibers and improve the quality of carbon fiber products. In the preparation process of carbon fiber, especially in the spinning, non-melting and high-temperature carbonization process of its precursor PAN, special oils and related oils have been developed, such as Japanese patents JP2008063705, JP2003253567, JP2003201346, The related oil agent disclosed in JP2003027378.

The process of preparing silicon carbide fiber is basically similar to that of carbon fiber, and compared with the fibril-polyacrylocyanine (PAN) fiber of carbon fiber, PCS fiber has lower strength and is more brittle after being touched. Therefore, the use of oil to protect PCS fibers to reduce damage and defects is particularly important for the preparation of continuous SiC fibers. However, in the preparation process of SiC fibers, for PCS fibers with low molecular weight and particularly fragile, so far, there is no suitable oil agent, and there are no related literature reports.

Contents of the invention

The purpose of the present invention is to provide a PCS fiber that protects the non-melting treatment from mechanical damage when it passes through a guide roller, improves the bundling and bundle strength of the PCS fiber, reduces the broken ends of the fiber, and improves the quality of the SiC fiber produced. Quality and performance of continuous silicon carbide fiber manufacturing oil and its application process.

Technical scheme of the present invention is as follows:

The oil agent for continuous silicon carbide fiber production of the present invention is a modified silicone oil aqueous solution or emulsion prepared by adding water to a modified silicone oil. The modified silicone oil is polysiloxane containing different active groups. The molecular structure is:

In the formula, x, y, z are the number of repeating units, x+z=10-1000, y=1-50, R is a modification group, depending on the modification group, the viscosity can be 600-3000mPa s (25°C) amino-modified silicone oil:

where K=1-5;

Or polyether-modified silicone oil with a viscosity of 1000-5000mPa·s (25°C):

Where a=1-30, b=0-20;

Or epoxy-modified silicone oil emulsion (20-40wt% concentration) with a viscosity of 2-50mPa s (25°C):

Or hydroxy-modified silicone oil with a viscosity of 10,000-800,000mPa·s (25°C):

The modified silicone oil aqueous solution or emulsion, wherein the concentration of the modified silicone oil is 0.01-5wt% (preferably 0.1-3wt%).

If the modified silicone oil concentration of the oil agent is lower than 0.01wt%, the oil agent can not spread evenly on PCS fibers or PCS infusible fibers (contact angle > 80°), and the fiber bundle property is poor; if it is higher than 5wt%, Then, although the above-mentioned modified silicone oil spreads well on the fiber surface (contact angle <40°, and in better case <30°), and has excellent bundling properties, it causes waste of oil and is difficult to quickly and completely degumming.

Preparation method: For the modified silicone oil with good water compatibility, directly add it into the water according to the predetermined proportion, stir it evenly, and dissolve it in water; for the modified silicone oil with poor water compatibility, add water After dilution, stir at high speed to form a uniform and stable emulsion.

The application process of using the modified silicone oil agent for continuous silicon carbide fiber manufacture is:

(1) multiple bundles of PCS non-melting fibers are stretched by guide rollers and then entered into an oil tank filled with the oil agent for bundling, then after being dried at a low temperature in a drying oven, they are wound onto the receiving bobbin;

(2) The PCS non-melting fibers bundled and dried by the oil agent are placed in a high-temperature furnace protected by an inert atmosphere to be fired, and then a winding device is used to wind the upper cylinder to obtain continuous SiC fibers.

The firing operation steps can be carried out continuously, and the continuous firing temperature is 1200-1400°C; the firing can also be carried out in two steps, that is, after oiling and drying, it is first pre-fired at 1000-1200°C, and cooled to After room temperature, the continuous SiC fiber is prepared through high-temperature final firing at 1200-1400°C.

The continuous PCS fibers or PCS non-melting fibers subjected to the oiling and bundling treatment may be in the form of fibers wound into a drum, or evenly arranged in a disc. The number of fiber bundles for oiling and bundling treatment is preferably 3-20 bundles. If it is less than 3 bundles, the production efficiency will be too low. If it is higher than 20 bundles, the arrangement of the wire drum or wire disc or the uniformity of product performance will be affected. There will be adverse effects.

The oil agent and oiling method are also applicable to the gluing of PCS (ie PTCS, PZCS, PACS, PYCS, PBCS) non-melting fibers containing metal elements and metalloid elements (such as Ti, Zr, Al, Y, B) Bundle processing is suitable for the preparation process of continuous SiC containing Ti, Zr, Al, Y, and B from these PCS fibers.

The precursor PCS of SiC fiber is a silicone polymer with Si-C bond as the main chain, which is relatively close to the modified silicone oil in the main chain structure. Therefore, the modified silicone oil used in the present invention as the oil agent for PCS fiber manufacturing should have good compatibility, and it is quite suitable for improving the film-forming and bundling properties of the oil agent on the PCS fiber.

Studies have shown that using the oil agent of the present invention to carry out oiling and bundling treatment of PCS infusible fibers has the following positive effects compared with the prior art:

1. It can effectively reduce the fluff and broken ends of PCS fibers caused by friction when they contact with the guide roller, and significantly improve the bundling of each bundle of fibers;

2. Due to the reduction of wool and broken ends, the bundled properties of the fiber bundles are improved, which can effectively improve the performance uniformity of the prepared SiC fibers;

3. The oil agent clustering technology adopted in the present invention requires simple equipment and simple process, and is easy to adopt and implement in the actual production line.

Description of drawings

FIG. 1 is a histogram of the intensity distribution of the continuous SiC fiber obtained in Comparative Example 1.

Fig. 2 is a histogram of intensity distribution of the continuous SiC fiber obtained in Example 1 of the present invention.

Detailed ways

The present invention will be further described below in conjunction with embodiment. However, these examples should not be used to interpret the limitation of the protection scope of the present invention.

Example 1

Dissolve 2.5 g of amino-modified silicone oil (AMPS according to its English abbreviation, purity 98%, pH=7.5, viscosity 1500 mPa·s) in 500 ml distilled water, stir evenly, and place it in an oil tank. After the continuous PCS fiber was placed in an oven at 200°C for 2 hours, its non-melting reaction degree (calculated based on the reaction consumption of Si-H bonds in PCS) was measured to be 65%, and the gel content in xylene was 86%. . Put 5 bundles of continuous PCS non-melting fibers obtained in this way into the oiling and bundling device, and then pass through the oil tank for oiling and bundling, and then dry them in a drying oven (temperature 120°C, time 1h), and then pass through them with high-purity nitrogen gas (purity 99.995%) protected high-temperature furnace (furnace temperature 1300 ° C), after high-temperature firing at a wire speed of 0.5m/min, it is wound on an upper drum to obtain continuous SiC fibers.

，其中n为样本量，F为最大拉伸载荷，d为纤维直径，

为纤维单丝强度，

为平均强度)。The broken end rate of the fiber was measured to be 3.9%, and 40 fiber monofilament samples were taken and the average diameter of the fiber was measured by the tensile method to be 12.8 μm , the average tensile strength was 2.69GPa, and the CV value of the tensile strength distribution was 23.0%. . (

, where n is the sample size, F is the maximum tensile load, d is the fiber diameter,

is the fiber monofilament strength,

is the average intensity).

Example 2

Take 30% epoxy-modified silicone oil emulsion (referred to as EMPS according to its English abbreviation, pH=7.0, viscosity is 5 mPa s) 3g and dissolve it in 180ml distilled water, stir at 300rpm for 1 hour to form a concentration of about 0.5% uniform emulsion, placed in the oil tank. 5 bundles of continuous PCS non-melting fibers after non-melting treatment under the same conditions as in Example 1 were continuously oiled and bundled in an oil tank, then dried in a drying furnace, and then degummed in a degumming furnace (processing temperature 700 ° C) and then wound on the upper cylinder To obtain continuous PCS bundled fibers, place the non-melting fibers in a high-temperature furnace, heat them to 1000°C for 1 hour under the protection of high-purity nitrogen at a heating rate of 150°C/hour, take them out after cooling to room temperature, and press 0.5m/h The wire-feeding speed of min enters the 1300 ℃ high-temperature furnace protected by high-purity nitrogen for firing, and winds up the upper drum to obtain continuous SiC fibers.

The measured fiber breakage rate was 4.7%, the average fiber diameter was 12.3 μm , the average tensile strength was 2.65GPa, and the CV value of the tensile strength distribution was 20.8%.

Example 3

Take polyether modified silicone oil (according to its English abbreviation as PMPS, purity 98%, pH=7.0, viscosity 2000 mPa·s) 3g dissolved in 300ml distilled water, stirred evenly and placed in the oil tank. Five bundles of the same continuous PCS non-melting fibers as in Example 1 were oiled, bundled, dried and fired at a high temperature of 1300°C according to the process flow of Example 1 to obtain continuous SiC fibers.

The fiber breakage rate was determined to be 4.1%, the average fiber diameter was 13.2 μm , the average tensile strength was 2.47GPa, and the CV value of the tensile strength distribution was 23.3%.

Example 4

Take 3 g of hydroxyl-modified silicone oil (referred to as HMPS according to its English abbreviation, purity 98%, pH=7.0, viscosity 300000mPa·s) in 300ml distilled water, stir evenly and place it in an oil tank. Five bundles of the same continuous PCS non-melting fibers as in Example 1 were oiled and bundled according to the process of Example 1, dried and fired at a high temperature of 1300°C to obtain continuous SiC fibers.

The fiber breakage rate was determined to be 3.2%, the average fiber diameter was 12.8 μm , the average tensile strength was 2.32GPa, and the CV value of the tensile strength distribution was 19.4%.

Comparative example 1

5 bundles of the continuous PCS non-melting fibers obtained after the same non-melting treatment as in Example 1 were bundled by guide rolls and then passed into a high-temperature furnace protected by high-purity nitrogen gas. After high-temperature treatment at a wire speed of 0.5 m/min, the coil Wind the upper cylinder to obtain continuous SiC fibers.

The fiber breakage rate was determined to be 9.7%, the average fiber diameter was 12.9 μm , the average tensile strength was 2.02GPa, and the CV value of the tensile strength distribution was 33.4%.

The results of the Examples and Comparative Examples are listed in Table 1.

It can be seen from Table 1 that compared with Comparative Example 1, after using the modified silicone oil agent, the PCS fibers prepared in Examples 1 to 4 all have good bundling properties, and are obtained by firing at high temperature. The broken end rate of the SiC fiber was significantly reduced from 9.7% in the control example to 3.2-4.7%. Correspondingly, the average tensile strength of the fiber was significantly increased. Compared with the control example, the strength increased by 15-33%. Due to the use of the same PCS non-melting fiber and the same preparation conditions, the strength of the fiber is improved because the fiber breakage rate is reduced after the oil is bundled, and because the fiber bundle is enhanced, the fiber is uniform during the firing process. Under tension, the strength uniformity of the prepared SiC fiber is improved. The C.V value representing the strength dispersion of 40 fiber samples was measured, and it can be seen that it dropped from 33.4% in the control example to 19.4-23.3%, indicating that the strength uniformity of SiC fibers obtained after oil agent bundling was significantly improved. The histograms of the intensity distributions of Comparative Example 1 and Example 1 are shown in Figure 1. It can be seen that compared with Comparative Example 1, the intensity distribution of SiC fibers prepared in Example 1 is more concentrated and uniform.

In summary, using the modified silicone oil agent of the present invention and its application process, in the production process of SiC fibers, it can effectively reduce the wool and broken ends caused by friction when the PCS fibers are in contact with the guide rollers, and improve the quality of the fibers. The bundling properties of SiC fibers can be significantly improved, and the mechanical properties and uniformity of properties of SiC fibers can be significantly improved, and the quality of fiber products can be improved, which has a good effect on the actual use of SiC fiber products. the

The present invention is also applicable to a series of SiC fibers made from other PCS fibers containing metal elements and metalloid elements (such as Ti, Zr, Al, Y, B). These fibers have high strength, high temperature resistance, With excellent properties such as high oxidation resistance, it has important application prospects in aviation, aerospace, nuclear industry, weaponry and other fields.

Claims (6)

1. a finishing oil for manufacturing of continuous silicone carbide fiber is characterized in that, for added water formulated modified organic silicon oil solution or emulsion by modification organic silicon oil, described modification organic silicon oil is the polysiloxanes that contains the different activities group, and its molecular structure is:

In the formula, x, y, z are the repetitive number, x+z=10-1000, and y=1-50, R are the modification group, according to the difference of modification group, are that viscosity is the amino-modified silicone oil of 600-3000 mPas:

K=1-5 wherein;

Or viscosity is the polyether modified silicon oil of 1000-5000 mPas:

A=1-30 wherein, b=0-20;

Or viscosity is the epoxide modified silicone oil emulsion of 2-50mPas:

Or viscosity is the hydroxyl modification silicone oil of 10000-800000mPas:

Described modified organic silicon oil solution or emulsion, wherein the concentration of modification organic silicon oil is 0.01-5wt%.

2. finishing oil for manufacturing of continuous silicone carbide fiber according to claim 1 is characterized in that, the concentration of described modification organic silicon oil is 0.1-3 wt%.

3. claim 1 or the 2 described finishing oil for manufacturing of continuous silicone carbide fiber technique for applying in making the continuous carbofrax fibre process is characterized in that:

(1) with multi beam PCS fusion-free fibre, apply through deflector roll and to enter the oil groove that is added with described finish behind the tension force and carry out boundling, be wound up into after the drying on the wire drawing tube;

(2) will place the high temperature kiln roasting of inert atmosphere protection by the PCS fusion-free fibre of described finish boundling oven dry, and adopt again and receive silk device winding top cylinder, promptly make continuous SiC fiber.

4. according to the technique for applying of the described finishing oil for manufacturing of continuous silicone carbide fiber of claim 3 in making the continuous carbofrax fibre process, it is characterized in that the boundling oven dry and burn till step and carry out continuously, firing temperature 1200-1400 ℃.

5. according to the technique for applying of the described finishing oil for manufacturing of continuous silicone carbide fiber of claim 3 in making the continuous carbofrax fibre process, it is characterized in that burning till step carries out step by step, promptly after the oven dry that oils, handle by 1000-1200 ℃ of pre-burning earlier, after being cooled to room temperature, burn eventually through 1200-1400 ℃ of high temperature again.

6. according to claim 3 or the 4 or 5 described finishing oil for manufacturing of continuous silicone carbide fiber technique for applying in making the continuous carbofrax fibre process, it is characterized in that, continuous P CS fiber or PCS fusion-free fibre that the described boundling that oils is handled are with the fibers form that is wound into tube or evenly arrange form in dish; The bundle number of the fiber that the boundling that oils is handled is the 3-20 bundle.

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