Preparation method and application of low-stretch polyester industrial yarn

Abstract

The application relates to a preparation method and application of low-elongation polyester industrial yarn, which comprises the following steps: first, high-orientation low-crystallization first-order polyester pre-yarn is prepared by melt spinning; and then, the first-order polyester pre-yarn is subjected to crystallization treatment under a high-orientation state to obtain low-elongation polyester industrial yarn; in the post-drawing process of melt spinning, the temperature of a setting roller is 180-200 DEG C, and a non-heating roller is arranged behind the setting roller; the crystallization treatment under the high-orientation state comprises orientation promotion (i) process and high-orientation crystallization strengthening (ii) process in sequence; the temperature of the orientation promotion (i) process is 195-210 DEG C, and the tension is lambda1zeta; the temperature of the high-orientation crystallization strengthening (ii) process is 220-235 DEG C, and the tension is lambda2zeta; epsilon is the internal stress of the first-order polyester pre-yarn at the process temperature; zeta is a fineness correction coefficient; lambda1 and lambda2 are tension process coefficients, the value range of lambda1 is 1.20-2.40, and the value range of lambda2 is 1.02-1.80; and the low-elongation polyester industrial yarn can be applied to geotechnical infrastructure materials. The low-elongation polyester industrial yarn prepared by the application has the characteristics of high strength, ultra-low elongation, high rigidity and excellent long-time stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polyester industrial yarns, and relates to a preparation method and application of low-elongation polyester industrial yarns. BACKGROUND

[0002] Polyester industrial yarns have the advantages of high strength, large modulus and good heat resistance, and are widely used in fields such as safety belts, hoisting belts, geotextiles, rubber skeleton materials and cables. According to the performance of polyester industrial yarns, they can be divided into high-strength type, high-strength low-elongation type, high-modulus low-shrinkage type and high-strength low-shrinkage type. In addition to the characteristics of high breaking strength and modulus shared by industrial yarns, low-elongation polyester industrial yarns also have the characteristic of low breaking elongation, that is, excellent stress dimensional stability, and are widely used in fields such as geotechnical construction, rubber reinforcement and ocean development. At present, the requirements for the physical indicators of low-elongation polyester industrial yarns in the technical field are limited by the technical level, and on the basis of meeting the basic strength requirements, the breaking elongation is mainly used to judge. In the production technology, the preparation of low-elongation polyester industrial yarns mainly innovates in the aspects of raw materials and process, and the improvement of the quality of raw materials and modification technology are mainly included in the raw material end. The patent with the application number CN201811078697.9 discloses a high-modulus low-elongation polyester industrial yarn for geotextiles and a production method thereof, adopts a solid-phase polymerization reactor for tackification, cooperates with a multi-head spinning process, two-stage drafting, one-stage relaxation, heat setting and high-speed winding by means of a twin roll winding machine, so as to realize the solid-phase tackification multi-head direct spinning of the high-modulus low-elongation polyester industrial yarn for geotextiles. The performance of the polyester industrial yarn is ensured to meet the demand of geotextiles by setting the drafting ratio, relaxation ratio, drafting temperature and relaxation temperature, and the specific index is that the breaking elongation is controlled to be less than or equal to 12.5%. The patent with the application number CN201610776464.0 discloses a high-uniformity high-strength low-elongation polyester industrial yarn and a preparation method thereof. The raw material of the polyester fiber is a modified polyester composed of terephthalic acid segments, ethylene glycol segments and branched diol segments, and the performance index of the high-uniformity high-strength low-elongation polyester industrial yarn is that the breaking strength is greater than or equal to 8.3 cN / dtex, and the breaking elongation is 10.0±1.5%.

[0003] In summary of the existing public technology, whether the quality of raw materials is improved and the technology is improved based on the existing spinning process and equipment, the core property index of low-stretch polyester industrial yarn, i.e., breaking elongation, is currently in the range of 10% to 14% under the basic strength requirement, and the technical level bottleneck is difficult to break through below 10%. In terms of comprehensive evaluation index, the existing index is generally limited to breaking elongation, and the evaluation index of size rigidity and stability is lacking. This is mainly caused by the limitations of the existing technology. The current production of low-stretch polyester industrial yarn is based on the polyester melt spinning (melt-spinning-drawing-winding) process and equipment. Under the existing high-speed winding spinning technology, all the technical cores are to improve the orientation of the fiber, especially the amorphous orientation. To achieve this structure regulation, the only way under the existing technical conditions is to reduce the disorientation caused by setting, i.e., to reduce the setting temperature, the overfeed rate, and to accelerate the cooling and solidification. However, the defect of this process is that the fiber crystallization is imperfect, and the amorphous area accounts for too large a proportion. The highly oriented amorphous structure is a non-thermal equilibrium unstable structure. Therefore, after winding and forming, the stress relaxation gradually occurs under the conditions of ambient temperature and humidity, the amorphous area disorients, the chain breaks shrink, resulting in an increase in breaking elongation, and the rigidity and stability deteriorate. Today, with the continuous innovation of social technology, the rapid development of transportation (such as high-speed railway, large airport, etc.), offshore oil exploitation and infrastructure, etc., the technical requirements for low-stretch polyester industrial yarn are continuously increasing. However, the breaking elongation index of the existing product is relatively large (poor load stability), the rigidity parameter r 5％ is about 40%, r Δ is above 60%, the long-term stability index η 4@E is above 1.500, and η 4@5％ is below 75%, which is difficult to meet the high-performance requirements. SUMMARY

[0004] The purpose of the present application is to solve the above-mentioned problems existing in the prior art and to provide a preparation method and application of low-stretch polyester industrial yarn.

[0005] To achieve the above-mentioned purpose, the technical solutions adopted by the present application are as follows:

[0006] A preparation method of low-stretch polyester industrial yarn, first, high-orientation low-crystallization first-order polyester preform is prepared by melt spinning, and then low-stretch polyester industrial yarn is prepared by crystallization treatment of the first-order polyester preform under high-orientation state.

[0007] In the post-drawing process of melt spinning, the setting roller temperature is 180 to 200℃, and the non-heated roller is behind the setting roller.

[0008] The crystallization treatment under high-orientation state includes orientation promotion (i) process and high-orientation crystallization strengthening (ii) process in sequence.

[0009] The temperature of the orientation re-promotion (i) process is 195-210 DEG C, and the tension is λ1ζ;

[0010] The temperature of the high orientation crystallization reinforcement (ii) process is 220-235 DEG C, and the tension is λ2ζ;

[0011] Wherein, ε is the internal stress of the first-order PET preform at the process temperature, and the unit is N; ζ is the fineness correction coefficient, D is the fineness of the first-order PET preform, and the unit is denier; λ1 and λ2 are the tension process coefficients, λ1 is in the range of 1.20-2.40, and λ2 is in the range of 1.02-1.80.

[0012] As a preferred technical solution:

[0013] The preparation method of the low-stretch PET industrial yarn as described above, the post-drawing process of melt spinning is 5 pairs of hot rollers, the 5 pairs of hot rollers are GR1-GR5, and GR4 is a setting roller;

[0014] The speed of GR1 is 450-650 m / min, the speed of GR5 is 2700-3200 m / min; the temperature of GR1 is 90±10 DEG C, the temperature of GR2 is 100±10 DEG C, the temperature of GR3 is 135±10 DEG C, the temperature of GR4 is 190±10 DEG C, and the temperature of GR5 is 110±5 DEG C.

[0015] The preparation method of the low-stretch PET industrial yarn as described above, the winding tension of melt spinning is The winding speed is 2800 m / min.

[0016] The preparation method of the low-stretch PET industrial yarn as described above, the fiber orientation degree of the first-order PET preform is 0.915-0.930, the amorphous zone orientation degree is 0.790-0.830, and the crystallinity is 56.0-60.0%.

[0017] The preparation method of the low-stretch PET industrial yarn as described above, the fiber orientation degree of the first-order PET preform after the orientation re-promotion (i) process is 0.935-0.965, the amorphous zone orientation degree is 0.820-0.840, and the crystallinity is 60.0-61.0%.

[0018] The preparation method of the low-stretch PET industrial yarn as described above, after the high orientation crystallization reinforcement (ii) process, the fineness orientation degree of the low-stretch PET industrial yarn is 0.935-0.965, the amorphous zone orientation degree is 0.820-0.840, and the crystallinity is 62.0-65.0%.

[0019] The method for preparing the low-elongation polyester industrial yarn as described above, the performance indicators of the low-elongation polyester industrial yarn are: breaking strength ≥ 8.0 cN / dtex, elongation at break (E) ≤ 8.5%, shrinkage 6.25 ± 0.30%, r 2％ ≥ 22%, r 5％ ≥ 65%, r Δ ≤ 35.0%, η 2@E < 1.010, η 2@2％ ≥ 97.0%, η 4@2％ ≥ 75%, η 2@5％ ≥ 98.0%, η 4@E < 1.180, η 4@5％ ≥ 80%;

[0020] r 2％ refers to the 2.0% elongation strength (σ 2％ ) ratio, that is, the strength value corresponding to the fiber deformation elongation of 2% accounts for the percentage of the breaking strength;

[0021] r 5％ refers to the 5.0% elongation strength (σ 5％ ) ratio, that is, the strength value corresponding to the fiber deformation elongation of 5% accounts for the percentage of the breaking strength;

[0022] r Δ refers to the difference ratio of the 5.0% elongation strength and the 8.0% elongation strength (σ 8％ ), r Δ = [(σ 8％ - σ 5％ ) / σ] * 100%;

[0023] η 2@E refers to the ratio of the fiber elongation at break after being placed in balance for 10 2 hours to the initial elongation at break;

[0024] η 2@2％ refers to the 2.0% elongation strength ratio retention rate after being placed in balance for 10 2 hours;

[0025] η 4@2％ refers to the 2.0% elongation strength ratio retention rate after being placed in balance for 10 4 hours;

[0026] η 2@5％ refers to the 5.0% elongation strength ratio retention rate after being placed in balance for 10 2 hours;

[0027] η 4@E refers to the ratio of the fiber elongation at break after being placed in balance for 10 4 hours to the initial elongation at break;

[0028] η 4@5％ This refers to placing 10 in a balanced manner. 4 The retention rate of 5.0% of the tensile strength after hours.

[0029] The method for preparing low-elongation polyester industrial yarn as described above involves balancing and allowing it to rest for 10 minutes. x The calculation method for the retention rate of y% tensile strength after hours is as follows: η x@y％ =(r x@y％ / r y％ )*100%, where x is 2 or 4, y is 2 or 5, and r x@y％ To balance the placement of 10 x The percentage of tensile strength after hours (y%).

[0030] In the preparation method of the low elongation polyester industrial yarn described above, balanced placement refers to placing it statically in an environment with a temperature of 25±5℃ and a relative humidity of 65±5%RH.

[0031] The present invention also provides the application of the low elongation polyester industrial yarn obtained by the method described above, which can be applied to geogrids, geotextiles and other geotechnical infrastructure materials.

[0032] The principle of this invention is as follows:

[0033] The core problem addressed by this invention is how to regulate fiber molecular chain segments, i.e., how to design and select the process route to achieve a stable, highly oriented microstructure, thereby achieving the goals of low elongation, high stiffness, and long-term stability. This invention employs melt spinning to prepare a first-order pre-formed filament with high orientation and low crystallinity. The mechanism is as follows: High fiber orientation is obtained under high-speed spinning conditions, primarily through orientation-induced crystallization during the drawing process. However, excessively rapid or high crystallization leads to numerous physical cross-linking points, hindering molecular chain segment stretching and making further orientation difficult, thus failing to achieve high orientation. Conversely, excessively low crystallinity also results in insufficient fiber stretching and a lack of stretching points. The core technology at this stage lies in controlling crystallization and improving orientation. In this process, the temperature of the setting roller is initially maintained at 190–200°C, close to but below the peak crystallization temperature of PET, controlling the crystallization rate. Furthermore, the setting overfeed rate is positive, meaning there is micro-stretching at the setting end, reducing molecular chain shrinkage. The roller following the setting roller and the roller before winding is a non-heated roller, with temperature control kept below 80°C (glass transition temperature) to increase cooling and weaken deorientation.

[0034] The mechanism of the second-order high-tension orientation promotion and the high-temperature crystallization process under this state lies in that the high orientation state of the preform yarn is a non-stable structure, and how to carry out orientation solidification is a technical key, and a key parameter of orientation control is a core, in the application, the orientation is controlled by tension based on the disorientation internal stress of the preform yarn at a certain process temperature (the orientation chain break occurs under the condition of heating), instead of the blind control of the orientation by the draft ratio. In the i-stage section of the present stage, the high orientation non-crystalline chain of the preform yarn is easy to disorient, and the multiple stress tension is adopted to maintain the original orientation state, so that the non-crystalline chain break crystallization becomes a stable state; on the other hand, the high multiple draft strengthens the orientation of the low orientation part of the non-crystalline region of the preform yarn, increases the overall orientation, and realizes the synchronization of orientation and crystallization. The ii-stage section is to strengthen crystallization under the condition of micro-super internal stress, the crystallinity has been greatly improved after the i-stage section, and the subsequent overlarge tension is easy to cause hair yarn due to the crystallization hindering the chain segment breakage, and the non-crystalline is easy to disorient, and the non-crystalline is not so easy to disorient due to the space limitation, therefore, the orientation chain segment of the non-crystalline region is promoted to crystallize under the condition of micro-super internal stress in this stage.

[0035] Beneficial effects:

[0036] (1) The preparation method of the low-stretch polyester industrial yarn of the application constructs and controls the high orientation microstructure of the stable state of the fiber, and the prepared low-stretch polyester industrial yarn has the characteristics of high strength, ultra-low stretch, high rigidity and excellent long-time stability performance;

[0037] (2) The preparation method of the low-stretch polyester industrial yarn of the application is based on the existing equipment and production technology, and is easy to implement after modification and process adjustment. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a tensile strength diagram;

[0039] Figure 2 is 10 x hours after the industrial yarn tensile curve diagram;

[0040] Figure 3 is a internal stress diagram of the polyester industrial yarn at different process temperatures. DETAILED DESCRIPTION

[0041] The application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the application and not to limit the scope of the application. In addition, it should be understood that those skilled in the art can make various modifications or modifications to the application after reading the content taught by the application, and these equivalent forms also fall within the scope defined by the claims attached to the present application.

[0042] The temperature of the PET melt is 290 DEG C, and the intrinsic viscosity is 0.98 dL / g.

[0043] In the embodiment of the application, the winding tension is The tension of the orientation re-promotion (i) process is λ1ζε, and the tension of the high orientation crystallization reinforcement (ii) process is λ2ζε; wherein, ε is the internal stress of the first-order PET preform at the process temperature (as shown in the formula (1)), and the unit is N; ζ is the fineness correction coefficient, Figure 3 D is the fineness of the first-order PET preform, and the unit is denier; λ1 and λ2 are the tension process coefficients, λ1 is 1.20-2.40, and λ2 is 1.02-1.80.

[0044] The test method used in the application is as follows:

[0045] (1) Fiber orientation degree: tested by the sound velocity orientation test method;

[0046] (2) Amorphous zone orientation degree: the sound velocity orientation test method is used to test the overall orientation degree of the fiber, and then the crystallinity and the crystal zone orientation degree are calculated according to the wide-angle X-ray diffraction test result, and the amorphous zone orientation degree is calculated;

[0047] (3) Crystallinity: tested by the X-ray diffraction technology (XRD);

[0048] (4) Breaking strength: tested by GB / T 16604-2017, and the test instrument is Instro-E3000 type electronic universal testing machine of Instron Company of the United States, and the test conditions are as follows: constant temperature and humidity environment (20 DEG C / 65% RH), clamping distance is 500 mm, and the tensile rate is 500 mm / min;

[0049] (5) Breaking elongation: tested by GB / T 16604-2017, and the test instrument is Instro-E3000 type electronic universal testing machine of Instron Company of the United States, and the test conditions are as follows: constant temperature and humidity environment (20 DEG C / 65% RH), clamping distance is 500 mm, and the tensile rate is 500 mm / min;

[0050] (6) Shrinkage rate: tested by GB / T 16604-2017, and the dry heat shrinkage test temperature is 177 DEG C, the time is 2 min, and the pre-tension is 0.05 cN dtex -1 ;

[0051] (7) r 2％ : refers to the percentage of 2.0% modulus (σ 2％ ), that is, the percentage of the strength value corresponding to the fiber deformation elongation of 2% to the breaking strength, as shown in the formula (2). Figure 1 ;​

[0052] (8) r 5％ : refers to the ratio of 5.0% constant elongation strength (σ 2％ ) to the breaking strength, i.e. the strength value corresponding to the elongation of 5% deformation of the fiber accounts for the percentage of the breaking strength, as shown in the following formula: Figure 1

[0053] (9) r Δ : refers to the ratio of the difference between 5.0% constant elongation strength and 8.0% constant elongation strength, r Δ = [(σ 8％ - σ 5％ ) / σ]*100%;

[0054] (10) η 2@E : refers to the ratio of the breaking elongation of the fiber after being placed in balance for 10 2 hours to the initial breaking elongation, as shown in the following formula: Figure 2

[0055] (11) η 2@2％ : refers to the retention rate of 2.0% constant elongation strength ratio after being placed in balance for 10 2 hours;

[0056] (12) η 4@2％ : refers to the retention rate of 2.0% constant elongation strength ratio after being placed in balance for 10 4 hours;

[0057] (13) η 2@5％ : refers to the retention rate of 5.0% constant elongation strength ratio after being placed in balance for 10 2 hours;

[0058] (14) η 4@E : refers to the ratio of the breaking elongation of the fiber after being placed in balance for 10 4 hours to the initial breaking elongation, as shown in the following formula: Figure 2

[0059] (15) η 4@5％ : refers to the retention rate of 5.0% constant elongation strength ratio after being placed in balance for 10 4 hours;

[0060] The calculation method of the retention rate of y% constant elongation strength ratio after being placed in balance for 10 x hours is: η x@y％ = (r x@y％ / r y％ )*100%, wherein x is 2 or 4, y is 2 or 5, and r x@y％ is the y% constant elongation strength ratio after being placed in balance for 10 x hours. The balance placement refers to the static placement in an environment with a temperature of 25±5℃ and a relative humidity of 65±5% RH.​​​

[0061] Example 1

[0062] A preparation method of low-stretch polyester industrial yarn, the specific steps are as follows:

[0063] (1) The PET melt is transported from the self-adhesion kettle to the metering pump and the spinning assembly through the pipeline, the melt is sprayed from the spinneret to form the primary fiber, and is collected by the GR1 roller;

[0064] Among them, the specification of the assembly filter screen is 25 microns, the side blowing air supply pressure is 800 Pa, the side blowing air temperature is 20℃, the side blowing air humidity is 78%, the side blowing air speed is 0.8 m / s, and the rear heating temperature is 300℃;

[0065] (2) The primary fiber obtained in step (1) is subjected to post-drawing by using 5 pairs of hot rollers, and the 5 pairs of hot rollers are GR1-GR5, and GR4 is a setting roller;

[0066] Among them, the temperature of GR1 is 80℃, the temperature of GR2 is 110℃, the temperature of GR3 is 125℃, the temperature of GR4 is 180℃, and the temperature of GR5 is 115℃;

[0067] The speed of GR1 is 476 m / min, the speed of GR2 is 516 m / min, the speed of GR3 is 2020 m / min, the speed of GR4 is 2865 m / min, and the speed of GR5 is 2860 m / min;

[0068] (3) After being drawn by the 5 pairs of hot rollers, winding is performed, the winding tension is 260 cN, and the winding speed is 2800 m / min, to obtain the high-orientation low-crystallization first-order polyester preform yarn with a fineness of 1000 denier;

[0069] The fiber orientation degree of the first-order polyester preform yarn is 0.920, the amorphous zone orientation degree is 0.816, and the crystallinity is 56.9%;

[0070] (4) The first-order polyester preform yarn is subjected to orientation re-promotion (i) process, the temperature of the orientation re-promotion (i) process is 195℃, the tension is 480 cN (the value of λ1 is 1.40), and after the first-order polyester preform yarn is subjected to the orientation re-promotion (i) process, the fiber orientation degree is 0.938, the amorphous zone orientation degree is 0.823, and the crystallinity is 60.2%;

[0071] (5) The product of step (4) is subjected to high-orientation crystallization strengthening (ii) process to obtain the low-stretch polyester industrial yarn, the temperature of the high-orientation crystallization strengthening (ii) process is 220℃, and the tension is 530 cN (the value of λ2 is 1.20).

[0072] The fineness orientation degree of the low-stretch polyester industrial yarn prepared is 0.945, the amorphous zone orientation degree is 0.821, and the crystallinity is 62.5%;

[0073] The performance indexes of the low-stretch polyester industrial yarn are as follows: the breaking strength is 8.15 cN / dtex, the breaking elongation is 8.4%, the shrinkage is 6.25%, the r 2％ is 23%, the r 5％ is 66%, the r Δ is 32.3%, the η 2@E is 1.007, the η 2@2％ is 98.5%, the η 4@2％ is 78%, the η 2@5％ is 98.5%, the η 4@E is 1.170, and the η 4@5％ is 81%.

[0074] The low-stretch polyester industrial yarn can be applied to geogrids, geotextiles and other geotechnical infrastructure materials.

[0075] Example 2

[0076] A preparation method of a low-stretch polyester industrial yarn, the specific steps are as follows:

[0077] (1) The PET melt is transported from the self-adhesion kettle to the metering pump and the spinning assembly through the pipeline, the melt is sprayed from the spinneret to form the primary fiber, and is collected by the GR1 roller;

[0078] Among them, the size of the assembly filter screen is 25 microns, the side blowing air supply pressure is 800 Pa, the side blowing air temperature is 20℃, the side blowing air humidity is 78%, the side blowing air speed is 0.8 m / s, and the post-heating temperature is 300℃;

[0079] (2) The primary fiber obtained in step (1) is subjected to post-drawing by using 5 pairs of hot rollers, the 5 pairs of hot rollers are GR1-GR5, and GR4 is a setting roller;

[0080] Among them, the temperature of GR1 is 100℃, the temperature of GR2 is 90℃, the temperature of GR3 is 130℃, the temperature of GR4 is 200℃, and the temperature of GR5 is 115℃;

[0081] The speed of GR1 is 486 m / min, the speed of GR2 is 516 m / min, the speed of GR3 is 2025 m / min, the speed of GR4 is 2875 m / min, and the speed of GR5 is 2855 m / min;

[0082] (3) After drawing by 5 pairs of hot rollers, winding is performed, the winding tension is 260 cN, and the winding speed is 2800 m / min, to obtain the high-orientation low-crystallinity first-order polyester preform yarn with a fineness of 1000 denier;

[0083] The fiber orientation degree of the first-stage polyester preformed yarn is 0.918, the amorphous zone orientation degree is 0.798, and the crystallinity is 58.6%;

[0084] (4) The first-stage polyester preformed yarn is subjected to orientation re-promotion (i) process, the temperature of the orientation re-promotion (i) process is 210℃, the tension is 510 cN (the value of λ1 is 1.32), and the fiber orientation degree of the first-stage polyester preformed yarn after the orientation re-promotion (i) process is 0.949, the amorphous zone orientation degree is 0.834, and the crystallinity is 60.6%;

[0085] (5) The product of step (4) is subjected to high orientation crystallization strengthening (ii) process, and low-stretch polyester industrial yarn is prepared, the temperature of the high orientation crystallization strengthening (ii) process is 235℃, and the tension is 800 cN (the value of λ2 is 1.65).

[0086] The fineness orientation degree of the prepared low-stretch polyester industrial yarn is 0.964, the amorphous zone orientation degree is 0.836, and the crystallinity is 64.5%;

[0087] The performance indexes of the low-stretch polyester industrial yarn are as follows: the breaking strength is 8.25 cN / dtex, the breaking elongation is 7.0%, the shrinkage is 6.50%, the r 2％ is 26%, the r 5％ is 68%, the r Δ is 30.7%, the η 2@E is 1.002, the η 2@2％ is 99.6%, the η 4@2％ is 80%, the η 2@5％ is 99.8%, the η 4@E is 1.082, and the η 4@5％ is 88%.

[0088] The low-stretch polyester industrial yarn can be applied to geogrid, geotextile and other geotechnical infrastructure materials.

[0089] Example 3

[0090] A preparation method of a low-stretch polyester industrial yarn, the specific steps are as follows:

[0091] (1) The PET melt self-bonding kettle is conveyed to the metering pump and the spinning assembly through the pipeline, the melt is sprayed from the spinneret to form the nascent fiber, and is collected by the GR1 roller;

[0092] Among them, the specification of the assembly filter screen is 25 microns, the side blowing air supply pressure is 800 Pa, the side blowing air temperature is 20℃, the side blowing air humidity is 78%, the side blowing air speed is 0.8 m / s, and the after-heating temperature is 300℃;

[0093] (2) using 5 pairs of hot rollers to post-draw the nascent fiber obtained in step (1), the 5 pairs of hot rollers are GR1-GR5, and GR4 is a setting roller;

[0094] wherein the temperature of GR1 is 90℃, the temperature of GR2 is 105℃, the temperature of GR3 is 135℃, the temperature of GR4 is 185℃, and the temperature of GR5 is 110℃;

[0095] the speed of GR1 is 496 m / min, the speed of GR2 is 506 m / min, the speed of GR3 is 2030 m / min, the speed of GR4 is 2885 m / min, and the speed of GR5 is 2850 m / min;

[0096] (3) after the drawing by the 5 pairs of hot rollers, winding is performed, the winding tension is 255 cN, and the winding speed is 2800 m / min, to obtain high-orientation low-crystallization first-order polyester preform with a fineness of 1000 denier;

[0097] the fiber orientation degree of the first-order polyester preform is 0.916, the amorphous zone orientation degree is 0.811, and the crystallinity is 57.7%;

[0098] (4) the first-order polyester preform is subjected to orientation re-promotion (i) process, the temperature of the orientation re-promotion (i) process is 200℃, and the tension is 860 cN (the value of λ1 is 2.23), after the orientation re-promotion (i) process, the fiber orientation degree of the first-order polyester preform is 0.946, the amorphous zone orientation degree is 0.828, and the crystallinity is 60.3%;

[0099] (5) the product of step (4) is subjected to high-orientation crystallization strengthening (ii) process, to obtain low-stretch polyester industrial yarn, the temperature of the high-orientation crystallization strengthening (ii) process is 225℃, and the tension is 520 cN (the value of λ2 is 1.10).

[0100] the fineness orientation degree of the obtained low-stretch polyester industrial yarn is 0.956, the amorphous zone orientation degree is 0.830, and the crystallinity is 63.0%;

[0101] the performance index of the low-stretch polyester industrial yarn is: breaking strength of 8.10 cN / dtex, elongation at break of 7.3%, shrinkage of 6.33%, r 2％ of 25%, r 5％ of 68%, r Δ of 31.1%, η 2@E of 1.005, η 2@2％ of 98.7%, η 4@2％ of 76%, η 2@5％ of 98.8%, η 4@E of 1.12, η 4@5％ of 84%.

[0102] The low-elongation polyester industrial yarn can be applied to geogrid, geotextile and other geotechnical infrastructure materials.

[0103] Embodiment 4

[0104] A preparation method of the low-elongation polyester industrial yarn, and the specific steps are as follows:

[0105] (1) The PET melt is transported from the self-adhesion kettle to the metering pump and the spinning assembly through the pipeline, the melt is sprayed from the spinneret to form the nascent fiber, and the nascent fiber is collected by the GR1 roller;

[0106] The specification of the assembly filter screen is 25 microns, the side blowing air supply pressure is 800 Pa, the side blowing air temperature is 20 DEG C, the side blowing air humidity is 78%, the side blowing air speed is 0.8 m / s, and the rear heating temperature is 300 DEG C.

[0107] (2) The nascent fiber obtained in step (1) is subjected to post-drawing by using 5 pairs of hot rollers, the 5 pairs of hot rollers are GR1-GR5, and GR4 is a setting roller;

[0108] The temperature of GR1 is 95 DEG C, the temperature of GR2 is 95 DEG C, the temperature of GR3 is 140 DEG C, the temperature of GR4 is 195 DEG C, and the temperature of GR5 is 110 DEG C.

[0109] The speed of GR1 is 476 m / min, the speed of GR2 is 506 m / min, the speed of GR3 is 2030 m / min, the speed of GR4 is 2895 m / min, and the speed of GR5 is 2845 m / min.

[0110] (3) After the drawing by the 5 pairs of hot rollers, the nascent fiber is wound, the winding tension is 530 cN, the winding speed is 2800 m / min, and the high-orientation low-crystallization first-order polyester preform yarn with a fineness of 2000 denier is obtained.

[0111] The fiber orientation degree of the first-order polyester preform yarn is 0.917, the amorphous zone orientation degree is 0.815, and the crystallinity is 57.8%.

[0112] (4) The first-order polyester preform yarn is subjected to the orientation re-promotion (i) process, the temperature of the orientation re-promotion (i) process is 205 DEG C, the tension is 1470 cN (the value of λ1 is 1.90), the fiber orientation degree of the first-order polyester preform yarn after the orientation re-promotion (i) process is 0.960, the amorphous zone orientation degree is 0.832, and the crystallinity is 60.4%.

[0113] (5) The product of step (4) is subjected to the high-orientation crystallization strengthening (ii) process, and the low-elongation polyester industrial yarn is prepared, the temperature of the high-orientation crystallization strengthening (ii) process is 230 DEG C, and the tension is 1210 cN (the value of λ2 is 1.24).

[0114] The low-stretch polyester industrial yarn has a fineness orientation degree of 0.960, an amorphous zone orientation degree of 0.832, and a crystallinity of 64.3%.

[0115] The low-stretch polyester industrial yarn has a breaking strength of 8.26 cN / dtex, an elongation at break of 7.1%, a shrinkage of 6.41%, a r 2％ of 24%, a r 5％ of 67%, a r Δ of 30.3%, a η 2@E of 1.003, a η 2@2％ of 98.4%, a η 4@2％ of 79%, a η 2@5％ of 99.0%, a η 4@E of 1.115, and a η 4@5％ of 86%.

[0116] The low-stretch polyester industrial yarn can be applied to geogrids, geotextiles and other geotechnical infrastructure materials.

[0117] Embodiment 5

[0118] A preparation method of a low-stretch polyester industrial yarn, the specific steps being as follows:

[0119] (1) The PET melt is transported from the self-adhesion kettle to the metering pump and the spinning assembly through the pipeline, the melt is sprayed from the spinneret to form the nascent fiber, and the nascent fiber is collected by the GR1 roller;

[0120] The filter screen of the assembly has a specification of 25 microns, the side blowing air supply pressure is 800 Pa, the side blowing air temperature is 20℃, the side blowing air humidity is 78%, the side blowing air speed is 0.8 m / s, and the post-heating temperature is 300℃.

[0121] (2) The nascent fiber obtained in step (1) is subjected to post-drawing by using 5 pairs of hot rollers, the 5 pairs of hot rollers being GR1 to GR5, and GR4 being the setting roller;

[0122] The GR1 temperature is 85℃, the GR2 temperature is 100℃, the GR3 temperature is 145℃, the GR4 temperature is 190℃, and the GR5 temperature is 105℃.

[0123] The GR1 speed is 486 m / min, the GR2 speed is 496 m / min, the GR3 speed is 2035 m / min, the GR4 speed is 2900 m / min, and the GR5 speed is 2840 m / min.

[0124] (3) After the drawing by the 5 pairs of hot rollers, the nascent fiber is wound at a winding tension of 550 cN and a winding speed of 2800 m / min to obtain the high-orientation low-crystallinity first-order polyester preform yarn with a fineness of 2000 denier.

[0125] The fiber orientation degree of the first-stage polyester preformed yarn is 0.923, the amorphous zone orientation degree is 0.822, and the crystallinity is 56.6%;

[0126] (4) The first-stage polyester preformed yarn is subjected to orientation re-promotion (i) process, the temperature of the orientation re-promotion (i) process is 210℃, the tension is 910 cN (λ1 is 2.25), the fiber orientation degree of the first-stage polyester preformed yarn after the orientation re-promotion (i) process is 0.961, the amorphous zone orientation degree is 0.834, and the crystallinity is 60.4%;

[0127] (5) The product of step (4) is subjected to high orientation crystallization strengthening (ii) process, and low-stretch polyester industrial yarn is prepared, the temperature of the high orientation crystallization strengthening (ii) process is 225℃, and the tension is 1030 cN (λ2 is 1.08).

[0128] The fineness orientation degree of the prepared low-stretch polyester industrial yarn is 0.964, the amorphous zone orientation degree is 0.838, and the crystallinity is 64.8%;

[0129] The performance indicators of the low-stretch polyester industrial yarn are as follows: breaking strength is 8.28 cN / dtex, elongation at break is 6.9%, shrinkage is 6.50%, r 2％ is 27%, r 5％ is 69%, r Δ is 30.1%, η 2@E is 1.006, η 2@2％ is 98.6%, η 4@2％ is 77%, η 2@5％ is 98.5%, η 4@E is 1.1170, η 4@5％ is 83%.

[0130] The low-stretch polyester industrial yarn can be applied to geogrid, geotextile and other geotechnical infrastructure materials.

[0131] Example 6

[0132] A preparation method of a low-stretch polyester industrial yarn, the specific steps are as follows:

[0133] (1) The PET melt self-bonding kettle is conveyed to the metering pump and the spinning assembly through the pipeline, the melt is sprayed from the spinneret to form the nascent fiber, and is collected by the GR1 roller;

[0134] Among them, the specification of the assembly filter screen is 25 microns, the side blowing air supply pressure is 800 Pa, the side blowing air temperature is 20℃, the side blowing air humidity is 78%, the side blowing air speed is 0.8 m / s, and the after-heating temperature is 300℃;

[0135] (2) using 5 pairs of hot rollers to post-draw the nascent fiber obtained in step (1), the 5 pairs of hot rollers are GR1-GR5, and GR4 is a setting roller;

[0136] wherein the temperature of GR1 is 90°C, the temperature of GR2 is 100°C, the temperature of GR3 is 130°C, the temperature of GR4 is 190°C, and the temperature of GR5 is 105°C;

[0137] the speed of GR1 is 496 m / min, the speed of GR2 is 496 m / min, the speed of GR3 is 2040 m / min, the speed of GR4 is 2905 m / min, and the speed of GR5 is 2820 m / min;

[0138] (3) after the drawing by the 5 pairs of hot rollers, winding is performed, the winding tension is 800 cN, and the winding speed is 2800 m / min, to obtain high-orientation low-crystallization first-order polyester preform with a fineness of 3000 denier;

[0139] the fiber orientation degree of the first-order polyester preform is 0.925, the amorphous zone orientation degree is 0.824, and the crystallinity is 56.5%;

[0140] (4) the first-order polyester preform is subjected to orientation re-promotion (i) process, the temperature of the orientation re-promotion (i) process is 205°C, and the tension is 2500 cN (λ1 is 2.10), after the orientation re-promotion (i) process, the fiber orientation degree of the first-order polyester preform is 0.951, the amorphous zone orientation degree is 0.829, and the crystallinity is 60.1%;

[0141] (5) the product of step (4) is subjected to high-orientation crystallization strengthening (ii) process, to obtain low-stretch polyester industrial yarn, the temperature of the high-orientation crystallization strengthening (ii) process is 230°C, and the tension is 2380 cN (λ2 is 1.27).

[0142] the fineness orientation degree of the obtained low-stretch polyester industrial yarn is 0.958, the amorphous zone orientation degree is 0.830, and the crystallinity is 63.9%;

[0143] the performance index of the low-stretch polyester industrial yarn is: breaking strength is 8.20 cN / dtex, elongation at break is 7.6%, shrinkage is 6.53%, r 2％ is 24%, r 5％ is 67%, r Δ is 33.0%, η 2@E is 1.009, η 2@2％ is 98.1%, η 4@2％ is 76%, η 2@5％ is 98.1%, η 4@E is 1.1175, η 4@5％ is 87%.

[0144] Low-stretch polyester industrial yarns can be applied to geogrids, geotextiles and other geotechnical infrastructure materials.

Claims

1. A method for preparing low-stretch polyester industrial yarn, characterized by: The first-order polyester preform is prepared by melt spinning, and the low-stretch polyester industrial yarn is prepared by crystallizing the first-order polyester preform in a high orientation state; In the post-drawing process of melt spinning, the temperature of the setting roller is 180-200 DEG C, and the setting roller is followed by a non-heated roller; The crystallization treatment in a high orientation state comprises orientation promotion (i) process and high orientation crystallization strengthening (ii) process in sequence; The temperature of the orientation promotion (i) process is 195-210 DEG C, and the tension is λ1ζε; The temperature of the high orientation crystallization strengthening (ii) process is 220-235 DEG C, and the tension is λ2ζε; Wherein, ε is the internal stress of the first-order polyester preform at the process temperature, and the unit is N; ζ is a fineness correction coefficient, D is the fineness of the first-order polyester preform, in denier; λ1and λ2are tension process coefficients, λ1is in the range of 1.20-2.40, and λ2is in the range of 1.02-1.

80.

2. The method for preparing low-elongation polyester industrial yarn according to claim 1, characterized in that, The post-drawing process of melt spinning is 5 pairs of hot roller drawing, and the 5 pairs of hot rollers are GR1-GR5, and GR4 is a setting roller; The speed of GR1 is 450-650 m / min, and the speed of GR5 is 2700-3200 m / min; the temperature of GR1 is 90±10 DEG C, the temperature of GR2 is 100±10 DEG C, the temperature of GR3 is 135±10 DEG C, the temperature of GR4 is 190±10 DEG C, and the temperature of GR5 is 110±5 DEG C.

3. The method for preparing low-elongation polyester industrial yarn according to claim 2, characterized in that, The take-up tension of melt spinning is The take-up speed is 2800 m / min.

4. The method for preparing low-elongation polyester industrial yarn according to claim 3, characterized in that, The fiber orientation degree of the first-order polyester preform is 0.915-0.930, the amorphous zone orientation degree is 0.790-0.830, and the crystallinity is 56.0-60.0%. The fiber orientation degree is tested by the sound velocity orientation test method; The test method of the amorphous zone orientation degree is that the overall fiber orientation degree is obtained by the sound velocity orientation test method, and then the crystallinity and the crystal zone orientation degree are calculated according to the wide-angle X-ray diffraction test result, and the amorphous zone orientation degree is calculated; The crystallinity is obtained by X-ray diffraction technology.

5. The method for preparing low-elongation polyester industrial yarn according to claim 4, characterized in that, The fiber orientation degree of the first-order polyester preform after the orientation promotion (i) process is 0.935-0.965, the amorphous zone orientation degree is 0.820-0.840, and the crystallinity is 60.0-61.0%.

6. The method for preparing low-elongation polyester industrial yarn according to claim 5, characterized in that, The fiber orientation degree of the low-stretch polyester industrial yarn is 0.935-0.965, the amorphous zone orientation degree is 0.820-0.840, and the crystallinity is 62.0-65.0%.

7. The method for preparing low-elongation polyester industrial yarn according to claim 6, characterized in that, The performance index of low-elongation polyester industrial yarn is: breaking strength ≥ 8.0 cN / dtex, elongation at break ≤ 8.5%, shrinkage 6.25 ± 0.30%, r 2％ ≥ 22%, r 5％ ≥ 65%, r Δ ≤ 35.0%, η2@ E < 1.010, η2@ 2％ ≥ 97.0%, η4@ 2％ ≥ 75%, η2@ 5％ ≥ 98.0%, η4@ E < 1.180, η4@ 5％ ≥ 80%; r 2％ is 2.0% of the tensile strength ratio; r 5％ is 5.0% of the tensile strength at a specific elongation; r Δ is the difference between the 5.0% modulus and the 8.0% modulus; η 2@ E is the ratio of the elongation at break after 10 2 hours of balanced resting to the initial elongation at break; η 2@2％ is the retention rate of 2.0% tensile strength after 10 2 hours of equilibrium placement; η 4@2％ is the retention rate of 2.0% tensile strength after 10 4 hours of equilibrium placement; η 2@5％ is the retention rate of 5.0% modulus retention after 10 2 hours of equilibrium placement; η 4@ E is the ratio of the elongation at break after 10 4 hours of balanced resting to the initial elongation at break; η 4@5％ is the retention rate of the 5.0% tensile strength at a given elongation after the sample is placed in equilibrium for 10 4 hours.

8. The method for preparing low-elongation polyester industrial yarn according to claim 7, characterized in that, Equilibrium placed 10 x hours later y% modulus retention rate calculation method is: η x@y％ = (r x@y％ / r y％ )*100%, wherein, x is 2 or 4, y is 2 or 5, r x@y％ is the y% modulus proportion after equilibrium placed 10 x hours later.

9. The method for preparing low-elongation polyester industrial yarn according to claim 8, characterized in that, The balance placement refers to the static placement in an environment with a temperature of 25±5 DEG C and a relative humidity of 65±5% RH.

10. The use of low-stretch polyester industrial yarns produced according to any one of claims 1 to 9, characterized in that: Applied to geotechnical infrastructure materials.

Images