A warm and dazzling black fiber and a spinneret for preparing the same and a production method

Abstract

The present invention discloses a heat-insulating, black fiber comprising a monofilament body with a triangular cross-section and a circular hollow through-hole disposed in the center of the monofilament body. The triangular cross-section of the monofilament body increases the reflective surface of the heat-insulating, black fiber, and the circular hollow through-hole structure imparts a heat-insulating effect to a fiber fabric woven from the monofilament body. This increases the probability of light being completely absorbed by the fiber, resulting in a darker fiber color and improved heat-insulating effect at the same masterbatch content. This allows the fiber fabric to have both good reflective and heat-insulating properties, resulting in excellent heat-insulating properties and a straight, straight appearance.

Description

Technical Field

[0001] The present invention relates to the field of fiber technology, and in particular to a heat-retaining and dazzling black fiber, a spinneret for preparing the fiber, and a production method. Background Art

[0002] Polyester fibers offer excellent textile and wear properties, such as a crisp appearance, resistance to creep, fatigue, friction, and corrosion, and are renowned for being iron-free and durable. They are widely used in home textiles, apparel, and industrial applications. However, due to the low number of polar groups and the absence of color-absorbing groups in the polyester molecular chain, as well as its highly regular structure, dense molecular arrangement, and high crystallinity, they exhibit poor dyeability. Therefore, research and improvement in polyester fiber dyeing are crucial. Currently, there are two methods for dyeing polyester fibers: dyeing after spinning (post-spinning fiber coloring) and dyeing before spinning (dope coloring).

[0003] The post-spinning fiber coloring method refers to dyeing white fibers with dyes after melt spinning into fibers. However, due to the poor dyeability of polyester fibers, disperse dyes are usually used for dyeing under high temperature and high pressure or with a carrier. When dyeing at high temperature and high pressure, the small amount of oligomers contained in the polyester fibers can easily diffuse from the fibers to the surface and even enter the dye solution, forming a viscous substance in the dye solution, which brings a lot of trouble to dyeing and post-processing and consumes a lot of energy.

[0004] The solution dyeing method involves directly adding masterbatch to the melt spinning process during the polyester fiber production process. This method fixes the dye molecules in the polyester fiber, thereby improving the color fastness of the yarn. With increasing demand for fabric appearance and color, and with societal calls for energy conservation and emission reduction, the solution dyeing method for producing colored yarn has become a key area of ​​transformation and upgrading for manufacturers. Furthermore, fiber cross-section profiling improves the fiber's optical properties, thereby enhancing dyeing performance. Furthermore, fibers with profiled cross-sections are transparent, shiny, and have a shimmering quality, which enhances the glossiness of solution-dyed fibers. Furthermore, the increased specific surface area of ​​fibers with the same linear density increases dyeing speed, leading to accelerated development of solution-dyed, shaped fibers.

[0005] Black polyester, as the colored polyester with the largest output, has a wide range of applications. In particular, black polyester with a soft touch, gentle luster, and warmth-retaining properties is used as a high-end automotive interior material for sports and luxury models.

[0006] Since carbon black is similar to a perfect black body and completely absorbs light, the more light it absorbs, the darker the fiber becomes. While existing triangular-section black fibers can retain some heat from incident light, they also tend to dissipate it easily, making it difficult to improve the heat storage function of the black fibers themselves. Consequently, fabrics woven with black fibers cannot achieve the desired warmth retention. Therefore, improvements to the fibers themselves are needed.

[0007] At the same time, since the fiber itself has a special-shaped cross-section and after the addition of carbon black masterbatch, it is easy for the tension or friction to be too high during spinning, resulting in a decrease in the strength of the tow and breakage, leading to problems such as lint, floating yarn, and loose yarn. In order to solve the above problems, it is necessary to increase the oiling rate to improve the bundleness, thereby reducing loose yarn. However, due to the special-shaped cross-section, the tow has a large specific surface area, resulting in relatively poor permeability of the oil. When the actual oil content of the tow is too high, it is easy for the outer layer of the tow to have more oil and the inner layer of the fiber to have less oil, which makes it easy to have uneven oiling, increase friction with the porcelain parts, and cause single yarn breakage, loose yarn, etc. When black fiber is used as a car interior, it is also prone to color changes after long-term exposure to the sun. Therefore, it is necessary to improve the existing black fiber production process. Summary of the Invention

[0008] In order to solve certain technical problems existing in the prior art, one of the purposes of this application is to provide a warm and dazzling black fiber, which can increase the probability of light being completely absorbed by the fiber, so that the fiber color is correspondingly darker at the same masterbatch content, and the warming effect is better, so that the fiber fabric has both good reflective effect and good thermal insulation performance, and has excellent thermal insulation performance and a straight effect.

[0009] The second purpose of this application is to provide a spinneret for preparing the warm and cool black fiber, which can effectively solve the problem of difficult production of hollow triangular black fibers and improve the fiber's thermal insulation and heat storage performance.

[0010] It can effectively solve the problem of difficult production of hollow triangular black fibers.

[0011] The third purpose of this application is to provide a method for producing warm and stylish black fiber, which is improved under the original process conditions, effectively solving the problems of uneven distribution of black fiber oil, large number of hairy and floating fibers, and waste of oil, and the improvement cost is low.

[0012] In order to solve the above existing technical problems, one of the objectives of this application is achieved by adopting the following technical solutions:

[0013] A warm and shiny black fiber includes a monofilament body with a triangular cross-section and a circular hollow through-hole arranged in the middle of the monofilament body. The warm and shiny black fiber increases the reflective surface through the monofilament body with a triangular cross-section, and the circular hollow through-hole structure enables the fiber fabric woven from the monofilament body to have a thermal insulation effect.

[0014] Preferably, each vertex corner of the monofilament body is provided with a leaf length extending outward.

[0015] Preferably, the leaf length is 0.8±0.1 mm.

[0016] Preferably, the ratio of the length to the width of the leaf is 7 to 8:1.

[0017] The second purpose of this application is achieved by the following technical solution:

[0018] A spinneret for preparing the warm and shiny black fiber comprises a spinneret body and a plurality of spinneret holes provided on the spinneret body, each of the spinneret holes being composed of three Y-shaped channels, the three channels constituting the spinneret holes being arranged in a triangular shape, and the inner side surfaces of the three channels being arc-shaped surface structures distributed in a circular shape, and the fibers ejected from two adjacent channels are connected to each other after melt expansion to form the warm and shiny black fiber.

[0019] The third objective of this application is achieved by the following technical solution:

[0020] A method for producing warm and shiny black fiber, the production method comprising: mixing polyester and carbon black masterbatch raw materials through a dynamic mixer, and then sequentially passing through a booster pump, a spinning assembly including a spinneret for extrusion, cooling and molding, oiling, a guide hook, a GR1 guide roller, a GR2 guide roller, and winding to obtain the warm and shiny black fiber, wherein a first pre-network is provided in front of the guide disk of the GR1 guide roller.

[0021] Preferably, the pre-network pressure of the first pre-network is 0.08-0.09 MPa.

[0022] Preferably, a second pre-network is provided in the guide disc of the GR2 godet.

[0023] Preferably, the pre-network pressure of the second pre-network is 0.09-0.10 MPa.

[0024] Preferably, 5-8% of an anti-hydrolysis agent is added to the oil used in the oiling process, so that the added anti-hydrolysis agent provides the polyester fiber with better temperature resistance and the oil has anti-aging properties.

[0025] Preferably, the anti-hydrolysis agent is a glycidyl ether epoxy compound hydrolysis stabilizer.

[0026] Preferably, the monofilament body extruded through the spinning assembly is cooled by ring blowing.

[0027] Preferably, the ring-blowing air box for cooling and forming is provided with a cooling device.

[0028] Preferably, the cooling device is provided on the air inlet pipe or the inlet of the ring-blowing air box of the cooling and forming process, and the temperature of the air after cooling by the cooling device is 15-17°.

[0029] Preferably, the oil nozzle in the oiling step is provided with two oil outlet holes, and an oil storage hole is provided below each of the oil outlet holes.

[0030] Preferably, the specifications of the warm and black fiber are 150-300dtex / 144f, the carbon black masterbatch content is ≥8.0% and ≤10.0%, the dyeing degree is ≥4.5, the breaking strength is ≥2.35cN / dtex, the elongation at break is 145±3%, the CV value of the strip unevenness is ≤1.1%, the oil content is 0.50±0.05%, the degree of special shape is ≥50%, and the excellent rate is above 97%.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The cross-sectional shape of the monofilament main body of the black fiber is a structure with an outer triangular outline and circular hollow through-holes. The outer triangular shape of the monofilament main body can increase the reflective surface of the fiber, making it have a larger reflective surface, while the hollow structure of the internal circular hollow through-holes can make the fiber fabric have a thermal insulation effect. Such a fiber fabric has both good reflective effect and good thermal insulation performance. In addition, the circular hollow structure can make the fiber have a higher modulus, and the fabric has better gloss, excellent thermal insulation performance and a straight effect. Especially for the warm and dazzling black fiber, which is close to a completely black body, carbon black itself completely absorbs light. The more light is absorbed, the darker the fiber color. The triangular cross-section makes the optical path of the incident light inside the fiber the longest, which can increase the probability of complete absorption of light, so that the fiber color is correspondingly darker and the thermal insulation effect is better at the same masterbatch content. At the same time, the use of a hollow cross-section increases still air, thereby improving thermal insulation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the fiber cross section of the present invention;

[0034] Figure 2 Schematic diagram of the spinneret surface in the present invention;

[0035] Figure 3 Schematic diagram of the structure of the spinneret in the present invention;

[0036] Figure 4 is a process flow chart of the present invention;

[0037] Figure 5 Schematic diagram of the cross-sectional structure of the oil nozzle in the oiling step of the present invention;

[0038] In the figure: 1. Circular hollow through hole; 2. Monofilament body; 3. Leaf length; 4. Spinneret body; 5. Spinneret hole; 6. Oil nozzle; 7. Oil outlet hole; 8. Oil storage hole. DETAILED DESCRIPTION

[0039] Below, the present application is further described in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0040] In the description of this application, it should be understood that the terms "up", "down", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on this application.

[0041] The terms "first," "second," and the like in this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship. Example 1:

[0042] like Figure 1 As shown, a warm and shiny black fiber includes a monofilament body 2 with a triangular cross-section and a circular hollow through-hole 1 arranged in the middle of the monofilament body 2. The warm and shiny black fiber increases the reflective surface through the monofilament body 2 with a triangular cross-section, and the fiber fabric woven with the monofilament body 2 has a thermal insulation effect through the circular hollow through-hole 1 structure.

[0043] The cross-sectional shape of the monofilament body 2 of the black fiber is an outer triangular outline and a circular hollow through-hole 1. The outer triangular shape of the monofilament body 2 can increase the reflective surface of the fiber, making it have a larger reflective surface, while the hollow structure of the internal circular hollow through-hole 1 can make the fiber fabric have a thermal insulation effect. Such a fiber fabric has both good reflective effect and good thermal insulation performance. Moreover, the circular hollow structure can make the fiber have a higher modulus, and the fabric has better gloss, excellent thermal insulation performance and a straight effect. Especially for the warm and dazzling black fiber in which carbon black is close to a completely black body, it completely absorbs light. The more light is absorbed, the darker the fiber color. The triangular cross-section makes the optical path of the incident light inside the fiber the longest, which can increase the probability of the light being completely absorbed, so that the fiber color is correspondingly darker and the thermal insulation effect is better at the same masterbatch content. At the same time, the use of a hollow cross-section increases still air, thereby improving thermal insulation performance.

[0044] A further improvement is that each vertex of the monofilament body 2 is provided with a leaf length 3 extending outward.

[0045] A fiber main body is extended outward from each vertex of the monofilament main body 2 with a triangular cross section to form a leaf length 3, which can make the fiber more profiled and have better warmth retention.

[0046] A further improvement is that the leaf length 3 is 0.8±0.1 mm; and the ratio of the length to the width of the leaf length 3 is 7~8:1.

[0047] Since the profile of the monofilament can improve the diffuse reflection effect of the fiber on light, the profile of the fiber will increase with the increase of the length and width ratio of the leaf length 3. However, when the length and width ratio of the leaf length 3 increases to a certain extent, the flow rate of the polyester in the spinneret 5 will be reduced, resulting in spinning breakage. When the length and width ratio is 7~8:1, the profile can be guaranteed to be ≥50%. Example 2:

[0048] like Figure 2 and Figure 3 As shown, a spinneret for preparing the warm and shiny black fiber includes a spinneret body 4 and a plurality of spinneret holes 5 provided on the spinneret body 4. Each of the spinneret holes 5 is composed of three Y-shaped channels. The three channels constituting the spinneret holes 5 are arranged in a triangular shape. The inner side surfaces of the three channels are arc-shaped surface structures with a circular distribution. The fibers ejected from two adjacent channels are connected to each other after melt expansion to form the warm and shiny black fiber.

[0049] Since the heat-insulating and dazzling black fiber has a triangular hollow structure and a leaf length of 3, the existing triangular spinneret is difficult to produce. Therefore, the spinneret holes 5 on the spinneret are improved. Each spinneret hole 5 on the spinneret is composed of three through holes similar to the Y-shaped structure, and the three through holes are arranged in a triangular shape. After spinning, the two corners of the Y-shaped fiber are connected to each other after expansion, forming an outer triangular shape and an inner circular hollow shape of the heat-insulating and dazzling black fiber, which effectively solves the problem of the difficulty in producing heat-insulating and dazzling black fiber. The mechanism of the spinneret innovation is as follows:

[0050] 1. The cross-section of the monofilament is an outer triangle with an inner circular hollow shape. The outer triangle shape is mainly because the fiber has a larger reflective surface, and the inner circular hollow structure can make the fiber fabric have a thermal insulation effect. Such a fiber fabric has both good reflective effect and good thermal insulation performance. Moreover, the circular hollow structure can make the fiber have a higher modulus, and the fabric has better gloss, excellent thermal insulation performance and a straight effect.

[0051] Second, carbon black is similar to a perfect black body, completely absorbing light. The more light it absorbs, the darker the fiber becomes, and the better its warmth retention. This is especially true with a triangular hollow fiber cross-section. When light enters the triangular hollow fiber cross-section, it is more likely to be incident and reflected by the carbon black particles, increasing the light absorption rate and thus enhancing warmth retention. Example 3:

[0052] like Figure 4 As shown, a method for producing warm and shiny black fiber comprises: mixing polyester and carbon black masterbatch raw materials through a dynamic mixer, and then passing through a booster pump, a spinning assembly including a spinneret for extrusion, cooling and molding, oiling, a guide hook, a GR1 guide roller, a GR2 guide roller, and winding to obtain the warm and shiny black fiber, wherein a first pre-network is provided in front of the guide disk of the GR1 guide roller; the specification of the warm and shiny black fiber is 150-300dtex / 144f, the carbon black masterbatch content is ≥8.0% and ≤10.0%, the dyeing degree is ≥4.5, the breaking strength is ≥2.35cN / dtex, the breaking elongation is 145±3%, the CV value of the yarn unevenness is ≤1.1%, the oil content is 0.50±0.05%, the degree of special shape is ≥50%, and the excellent rate is above 97%.

[0053] Since the warm and cool black fiber has an irregular cross-section and a large specific surface area of ​​the yarn bundle, the permeability of the oil agent is relatively poor. When the fiber has an irregular cross-section and the actual oil content of the yarn bundle is too high, it is easy for the outer layer of the yarn bundle to have more oil and the inner layer of the fiber to have less oil. Because the cross-sectional shape affects the uneven distribution of the oil agent, usually the specific surface area of ​​the fiber with an irregular cross-section is larger than that of the fiber with a circular cross-section, which makes it easy for uneven oiling. At the same time, the fiber with an irregular cross-section has poor bundling, which further makes the oil agent unevenly distributed. Therefore, in order to reduce the problem of loose loops in the special black fiber, it is necessary to increase the oiling rate and improve the bundling, thereby reducing loose loops. The invention adds a first pre-network in front of the guide disc of the GR1 guide roller to "penetrate" the oil agent into the inside of the yarn bundle, solving the problem of a large amount of oil agent accumulating on the fiber surface. The oil will be scraped directly when passing through the guide hook, resulting in a decrease in the actual oil content and a large amount of oil waste.

[0054] A further improvement is that the pre-network pressure of the first pre-network is 0.08-0.09 MPa.

[0055] The reason why the first pre-network uses an air pressure of 0.08-0.09Mpa is that if the pre-network pressure is too high, the oil on the surface of the tow will be easily blown away, resulting in a decrease in the actual oil content. At the same time, due to excessive air pressure, the tow will be easily blown from the center of the pre-network device to the edge of the pre-network device, increasing the friction with the porcelain parts, resulting in single-filament breakage, loose loops, etc. If the pre-network pressure is too low, the tow will not be blown away, and the oil will not be able to penetrate. Therefore, it is necessary to accurately control the first pre-network pressure added in front of the GR1 guide disc. When the pre-network pressure is 0.08-0.09Mpa, the above problems can be effectively avoided.

[0056] A further improvement is that a second pre-network is provided in the guide disc of the GR2 godet roller.

[0057] Because the fiber has a special-shaped cross-section and is added with carbon black masterbatch, excessive tension or friction during spinning can easily cause the tow strength to decrease and break, leading to problems such as lint, drifting yarn, and loose loops. Therefore, to reduce the loose loop problem of special black fiber, while increasing the oiling rate to improve the bunching, it is also necessary to reduce the problems of drifting yarn and loose loops. To solve the above problems, in addition to adding a first pre-network in front of the guide disc of the GR1 godet roller, it is also necessary to add a second pre-network in the guide disc of the GR2 godet roller. That is, a pre-network is added in front of the guide disc of the GR1 godet roller and in the guide disc of the GR2 godet roller, which can effectively reduce the occurrence of drifting yarn and loose loops.

[0058] A further improvement is that the pre-network pressure of the second pre-network is 0.09-0.10 MPa.

[0059] Because some of the floating threads are easily absorbed in the normal yarn bundle after being oiled, the pre-network pressure of the second pre-network is 0.09-0.10Mpa, the purpose of which is to blow away the small floating threads absorbed in the yarn bundle.

[0060] Preferably, 5-8% of an anti-hydrolysis agent is added to the oil used in the oiling process, so that the added anti-hydrolysis agent provides the polyester fiber with better temperature resistance and the oil has anti-aging properties.

[0061] Since this fiber is primarily used in automotive interiors, it is prone to discoloration after prolonged exposure to sunlight. Anti-hydrolysis agents can provide polyester fibers with superior heat resistance and enhance the anti-aging properties of the oil. However, excessive amounts of anti-hydrolysis agents can lead to poor product bundle integrity, excessive lint during extrusion, and decreased physical performance. Excessive amounts of anti-hydrolysis agents fail to improve heat and humidity resistance. Therefore, the addition of anti-hydrolysis agents should be controlled between 5-8%, with 5-6% providing a more stable effect and requiring a smaller dosage.

[0062] A further improvement is that the anti-hydrolysis agent is a glycidyl ether epoxy compound hydrolysis stabilizer.

[0063] The anti-hydrolysis agent uses a glycidyl ether epoxy compound hydrolysis stabilizer, which generates a hydroxyl group through the reaction of the epoxy group with the carboxyl group produced by hydrolysis, thereby inhibiting the catalytic effect of the carboxyl group on hydrolysis; the epoxy group also reacts with the hydroxyl group to reconnect the broken chains produced by hydrolysis.

[0064] A further improvement is that the monofilament body 2 extruded through the spinning assembly is cooled by ring blowing.

[0065] Since the monofilament body 2 is a special-shaped fiber, conventional side-blowing cooling can easily cause uneven cooling and deformation. Therefore, a ring-blowing bellows is used for ring-blowing cooling during cooling and forming, which is more uniform than conventional side-blowing cooling.

[0066] A further improvement is that the cooling and forming ring-blowing air box is provided with a cooling and temperature reduction device.

[0067] Since the monofilament main body 2 is a special-shaped fiber, a fast cooling speed is required to improve the special-shaped degree, and it must be uniform. Therefore, there are lower requirements for the temperature of the ring-blowing air in the air duct. Because it is a special black silk, it is easy for a large amount of heat to be released during the ring-blowing air cooling, resulting in a problem of temperature rise. Therefore, a cooling device is installed on the ring-blowing air box. The cooling device can achieve a cooling effect, which can effectively solve the problem of unstable special-shaped degree of the monofilament main body 2.

[0068] A further improvement is that the cooling and temperature reduction device is arranged on the air inlet pipe or the inlet of the ring-blowing air box of the cooling and forming process, and the temperature of the air after being cooled by the cooling and temperature reduction device is 15~17°.

[0069] The cooling device can use a water pipe to transport condensed water for cooling, or it can use a condenser and other equipment to cool the supply air, thereby achieving control of the inner ring blowing temperature of the cooling molding process.

[0070] A further improvement is that the oil nozzle 6 in the oiling step is provided with two oil outlet holes 7 , and an oil storage hole 8 is provided below each of the oil outlet holes 7 .

[0071] During the oiling step, the oil nozzle 6 often encounters the problem of oil scraping due to incomplete penetration when oiling the tow from the oil outlet hole 7. Therefore, an inwardly recessed oil storage hole 8 is formed under each oil outlet hole 7. The oil storage hole 8 can be used to scrape off the unpenetrated oil and perform secondary oiling. Therefore, the improvement of the oil nozzle 6 effectively reduces the occurrence of oil scraping and makes the oiling effect more ideal.

[0072] The above-mentioned embodiments are only preferred embodiments of the present application and cannot be used to limit the scope of protection of the present application. Any non-substantial changes and replacements made by technicians in this field based on the present application shall fall within the scope of protection required by the present application.

Claims

1. A method for producing a heat-retaining black fiber, the method comprising: The polyester and carbon black masterbatch raw materials are mixed in a dynamic mixer, and then sequentially passed through a booster pump, a spinning assembly including a spinneret, extruded, cooled and formed, oiled, a godet hook, a GR1 godet roller, a GR2 godet roller, and wound to produce a warm and dazzling black fiber, characterized by: The spinneret has a triangular cross-section, a circular hollow through hole (1) is provided in the middle of the monofilament body (2), and each vertex of the monofilament body (2) is provided with a leaf length (3) extending outward; the leaf length (3) is 0.8±0.1 mm; and the length-to-width ratio of the leaf length (3) is 7-8:1; A first pre-network is provided in front of the guide disc of the GR1 godet; the pre-network pressure of the first pre-network is 0.08-0.09Mpa, and two oil outlet holes (7) are provided on the oil nozzle (6) in the oiling step, and an oil storage hole (8) is provided below each of the oil outlet holes (7); a second pre-network is provided in the guide disc of the GR2 godet; the monofilament body (2) extruded through the spinning assembly is cooled by ring blowing; a cooling and cooling device is provided on the ring blowing bellows for cooling and forming; the cooling and cooling device is provided on the air inlet pipe of the cooling and forming process or the inlet of the ring blowing bellows, and the temperature of the air cooled by the cooling and cooling device is 15-17°; 5-8% of an anti-hydrolysis agent is added to the oil used in the oiling process, and the added anti-hydrolysis agent provides the polyester fiber with better temperature resistance and the oil anti-aging performance.

2. The method for producing a warm and attractive black fiber according to claim 1, characterized in that: The anti-hydrolysis agent is a glycidyl ether epoxy compound hydrolysis stabilizer.

3. The method for producing the warm and attractive black fiber according to claim 1, characterized in that: The specifications of the warm and black fiber are 150-300dtex / 144f, the carbon black masterbatch content is 8.0%~10.0%, the dyeing degree is ≥4.5, the breaking strength is ≥2.35cN / dtex, the elongation at break is 145±3%, the CV value of the yarn unevenness is ≤1.1%, the oil content is 0.50±0.05%, the degree of special shape is ≥50%, and the excellent rate is ≥97%.

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