Polyamide composite fiber and preparation method and application thereof

Abstract

The application relates to the technical field of polyamide materials, and discloses a polyamide composite fiber and a preparation method and application thereof.The polyamide composite fiber comprises a first component and a second component, the first component is a polyamide 56 fiber, and the second component is other polyamide fibers, the other polyamide fibers are selected from at least one of a polyamide 6 fiber, a polyamide 66 fiber, a polyamide 510 fiber, a polyamide 511 fiber, a polyamide 512 fiber, a polyamide 610 fiber, a polyamide 611 fiber and a polyamide 612 fiber.The polyamide composite fiber provided by the application has the characteristics of double-color or multi-color effect, low shrinkage effect, high elastic fluffy, better mechanical properties and evenness of strip.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyamide materials, in particular to a polyamide composite fiber and a preparation method and application thereof. BACKGROUND

[0002] The bio-based polyamide 56 raw material and processing process are green and environmentally friendly, and the prepared fiber has better moisture absorption and quick drying properties (official moisture regain of 6% is closer to cotton, and the official moisture regain of ordinary nylon is 4-5%), skin friendliness, wear resistance, good softness, and low-temperature easy dyeing characteristics, and can be widely applied to the field of clothing filaments.

[0003] At present, the clothing field includes pre-oriented yarn (POY), elastic yarn (DTY), fully drawn yarn, medium-oriented yarn, high-oriented yarn, and elastic yarn, which has good bulkiness and elasticity and is widely used in the clothing field.

[0004] However, there are few reports on polyamide fibers with double or multi-color, low shrinkage, and high elastic bulkiness. SUMMARY

[0005] A first object of the present application is to provide a polyamide composite fiber with double or multi-color effect. By selecting polyamide fibers with different end amino content, relative viscosity, and specifications for compounding, a polyamide composite fiber with double or multi-color effect can be prepared by dyeing.

[0006] A second object of the present application is to provide a polyamide composite fiber with low shrinkage effect.

[0007] A third object of the present application is to provide a polyamide composite fiber with high elastic bulkiness effect.

[0008] A fourth object of the present application is to provide a polyamide composite fiber with better mechanical properties and evenness.

[0009] A fifth object of the present application is to provide a preparation method of a polyamide composite fiber with double or multi-color effect, low shrinkage effect, high elastic bulkiness, better mechanical properties, and evenness.

[0010] A sixth object of the present application is to provide an application of the polyamide composite fiber in the field of knitted and woven fabrics.

[0011] To achieve the above objects, the solution of the present application is:

[0012] A polyamide composite fiber comprising a first component and a second component, the first component being a polyamide 56 fiber, the second component being other polyamide fiber selected from at least one of polyamide 6 fiber, polyamide 66 fiber, polyamide 510 fiber, polyamide 511 fiber, polyamide 512 fiber, polyamide 610 fiber, polyamide 611 fiber and polyamide 612 fiber.

[0013] In some specific embodiments of the present application, the mass ratio of the polyamide 56 fiber to the other polyamide fiber is 20:80-80:20, preferably 30:70-70:30, further preferably 40:60-60:40.

[0014] Further, the other polyamide fiber is selected from at least one of polyamide 6 fiber, polyamide 66 fiber and polyamide 510 fiber.

[0015] According to a preferred embodiment of the present application, the end amino group content of the first component polyamide 56 fiber is 60-150 mmol / kg, preferably 65-130 mmol / kg, further preferably 70-110 mmol / kg. Specific examples are 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150 mmol / kg, etc.

[0016] According to a preferred embodiment of the present application, the relative viscosity of the first component polyamide 56 fiber is 2.4-3.0, preferably 2.5-2.9, further preferably 2.6-2.8. Specific examples are 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, etc.

[0017] According to a preferred embodiment of the present application, the end amino group content of the second component other polyamide fiber is 25-55 mmol / kg, preferably 30-50 mmol / kg, further preferably 35-45 mmol / kg. Specific examples are 25, 30, 35, 40, 45, 50, 55 mmol / kg, etc.

[0018] According to a preferred embodiment of the present application, the relative viscosity of the second component other polyamide fiber is 2.3-2.6, preferably 2.35-2.58, further preferably 2.4-2.55. Specific examples are 2.3, 2.35, 2.4, 2.45, 2.5, 2.55, 2.6, etc.

[0019] In some embodiments of the present application, the first component polyamide 56 fiber or the second component other polyamide fiber has a fineness of 10 to 150 dtex, preferably 20 to 120 dtex, and further preferably 30 to 90 dtex; and / or

[0020] The first component polyamide 56 fiber or the second component other polyamide fiber has a number of pores of 7 to 192 f, preferably 12 to 144 f, and further preferably 18 to 96 f.

[0021] In the present application, the polyamide composite fiber satisfies the following conditions: the breaking strength of the polyamide composite fiber is ≥ 3.0 cN / dtex, preferably ≥ 3.2 cN / dtex, and further preferably ≥ 3.4 cN / dtex; and / or

[0022] The polyamide composite fiber has a yarn irregularity of ≤ 1.3%, preferably ≤ 1.2%, and further preferably ≤ 1.1%; and / or

[0023] The polyamide composite fiber has an elongation at break of ≤ 90%, preferably ≤ 85%, and further preferably ≤ 80%; and / or

[0024] The polyamide composite fiber has an initial modulus of ≤ 40 cN / dtex, preferably ≤ 35 cN / dtex, and further preferably ≤ 33 cN / dtex; and / or

[0025] The polyamide composite fiber has a boiling water shrinkage of ≤ 12%, preferably ≤ 11%, and further preferably ≤ 10%; and / or

[0026] The polyamide composite fiber has a curling shrinkage of ≥ 35%, preferably ≥ 40%, and further preferably ≥ 45%; and / or

[0027] The polyamide composite fiber has a soaping fastness: a color fading fastness of ≥ 3.5, preferably ≥ 4.0, and further preferably ≥ 4.5; and a color staining fastness of ≥ 3.5, preferably ≥ 4.0, and further preferably ≥ 4.5; and / or

[0028] The polyamide composite fiber has a 15% elongation elastic recovery of ≥ 92%, preferably ≥ 94%, and further preferably ≥ 95%.

[0029] In the present application, the polyamide composite fiber has a production rate of ≥ 92%, preferably ≥ 94%, and further preferably ≥ 96%.

[0030] In the present application, the polyamide composite fiber includes undrawn yarn (UDY), pre-oriented yarn (POY), high-oriented yarn (HOY), fully-oriented yarn (FOY), fully drawn yarn (FDY), draw textured yarn (DTY), preferably pre-oriented yarn (POY), draw textured yarn (DTY) or fully drawn yarn (FDY).

[0031] A method for preparing a polyamide composite fiber, the method comprising:

[0032] (1) heating a polyamide 56 resin and other polyamide resins to a molten state respectively to form two polyamide melts;

[0033] (2) respectively conveying the two polyamide melts to a spinning beam through respective melt pipes, accurately metering through a metering pump, and injecting into a spinning assembly to form primary fibers through a spinneret hole, wherein a single suction device is arranged below each spinneret plate;

[0034] (3) respectively cooling, oiling, stretching and winding the two primary fibers to obtain two polyamide fibers; or cooling, oiling and stretching the two primary fibers, and then winding together in proportion to obtain a ply polyamide fiber;

[0035] (4) texturing the two polyamide fibers together in proportion, or directly texturing the ply polyamide fiber to obtain a polyamide composite fiber.

[0036] In the present application, the other polyamide resin is at least one selected from polyamide 6 resin, polyamide 66 resin, polyamide 510 resin, polyamide 511 resin, polyamide 512 resin, polyamide 610 resin, polyamide 611 resin and polyamide 612 resin, preferably at least one selected from polyamide 6 resin, polyamide 66 resin and polyamide 510 resin.

[0037] In some specific embodiments of the present application, the temperature of the spinning beam is 245-300℃, preferably 250-290℃.

[0038] In some specific embodiments of the present application, the pressure of the spinning assembly is 10-18MPa, preferably 12-16MPa.

[0039] In some specific embodiments of the present application, the cooling is cooling by side blowing, the air speed of the side blowing is 0.3-0.5m / s, preferably 0.4-0.45m / s; and / or, the air temperature of the side blowing is 16-22℃, preferably 18-20℃; and / or, the humidity of the side blowing is 75-95%, preferably 80-90%.

[0040] In some specific embodiments of the present application, the oiling rate is 0.4-0.55%, preferably 0.45-0.5%.

[0041] In some specific embodiments of the present application, the winding speed is 4200-5500 m / min, preferably 4300-5000 m / min.

[0042] In some specific embodiments of the present application, in step (4), the texturing includes the following steps: passing the polyamide fiber through a guide, a first roller, heat stretching in a heat box, then cooling and setting with a cooling plate, false twisting, passing through a tension on-line detector, a second roller, then passing through a network nozzle, a third roller, a filament breaking sensor, oiling, and winding to obtain the polyamide composite fiber; wherein,

[0043] The friction sheet for false twisting is selected from a C-type disc, a D-type disc, and a PU-type disc, preferably a C-type disc; and / or

[0044] The temperature of the heat box is 155-200°C, preferably 160-195°C, and further preferably 165-190°C; and / or

[0045] The heat stretching ratio is 1.20-1.40, preferably 1.23-1.35, and further preferably 1.25-1.32; and / or

[0046] The D / Y ratio of the false twisting is 1.6-2.2, preferably 1.65-2.1, and further preferably 1.7-2.0; and / or

[0047] The T2 processing tension control of the false twisting is 0.8-1.1 times, preferably 0.85-1.05 times, and further preferably 0.9-1.0 times of the T1 tension; and / or

[0048] The winding speed is 500-800 m / min, preferably 550-750 m / min, and further preferably 600-700 m / min.

[0049] A polyamide composite fiber with double or multiple colors, the polyamide composite fiber as described above is dyed with a dye to obtain a polyamide composite fiber with double or multiple colors.

[0050] According to a preferred embodiment of the present application, the dye includes acid dyes, reactive dyes, neutral dyes, direct dyes, metal complex dyes, vegetable dyes, and disperse dyes, and more preferably acid dyes, reactive dyes, neutral dyes, and metal complex dyes.

[0051] An application of a polyamide composite fiber in the field of knitted and woven fabrics.

[0052] By the technical scheme, the application has the following beneficial effects:

[0053] First, the raw material of the polyamide composite fiber of the application contains 1,5-pentanediamine, which is made by a biological method and is a green material, does not depend on petroleum resources and does not cause serious pollution to the environment, and can reduce the emission of carbon dioxide and the generation of greenhouse effect, and adapts to the development trend of carbon neutralization.

[0054] Second, the polyamide composite fiber of the application has good double-color or multi-color effect, low shrinkage and high elastic fluffy effect.

[0055] Third, the polyamide composite fiber of the application has the characteristics of small strip dryness and good dyeing performance.

[0056] Fourth, the polyamide composite fiber of the application can be prepared by using conventional polyamide 6 and polyamide 66 spinning and elasticizing equipment, without the need to modify the spinning equipment, and the production rate can be improved by optimizing the spinning and elasticizing process. DETAILED DESCRIPTION

[0057] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are understood to be approximate values. The endpoints of the ranges of values and the values thereof can be combined with one another even though not expressly stated in the application. The endpoints of the ranges of values and the values thereof can be combined with one another to create a new range of values.

[0058] The application will be described in detail below by way of examples. In the following examples, the various raw materials used are available from commercial channels unless otherwise specified.

[0059] 1. Detection method of relative viscosity ηr

[0060] Ubbelohde viscometer concentrated sulfuric acid method: accurately weigh 0.5±0.0002 g of the dried polyamide sample, add 50 mL of concentrated sulfuric acid (96 wt%) to dissolve, measure and record the concentrated sulfuric acid flow time t0 and the polyamide solution flow time t in a 25℃ constant temperature water bath.

[0061] Relative viscosity calculation formula: relative viscosity ηr=t / t0, wherein: t: solution flow time; t0: solvent flow time.

[0062] 2. Determination of terminal amino group content

[0063] According to the determination of the automatic titrator, after dissolving the sample with trifluoroethanol, the sample is titrated with hydrochloric acid standard solution and sodium hydroxide standard solution respectively, and the calculation is carried out.

[0064] 3. Breaking strength, elongation at break, initial modulus: the breaking strength of the filament can be measured according to GB / T 14344-2008 Chemical fiber tensile property test method; 0.05±0.005 cN / dtex pre-tension is applied, the holding distance is 500 mm, and the tensile speed is 500 mm / min. Modulus = breaking strength corresponding to 1% elongation at break x 100.

[0065] 5. Soaping fastness: measured according to GB / T 3921.1-1997.

[0066] 6. Crimp shrinkage: measured according to GB / T 6506-2001 Synthetic fiber textured yarn crimp property test method.

[0067] 7. Fineness: measured according to GB / T 14343.

[0068] 8. Boiling water shrinkage: refer to GB / 6505-2008 Chemical fiber filament thermal shrinkage test method, boiling water shrinkage = [(length before heat treatment - length after heat treatment) / length before heat treatment] * 100%.

[0069] 9. Production rate: production rate = (number of polyamide 56 finished fibers prepared / total number of polyamide 56 resin chips input) * 100%.

[0070] 10. Unevenness: measured according to GB / T 14346-93 method.

[0071] 11. Elastic recovery rate = [(L-L1) / (L-L0)] x 100%, wherein: L0 is the original length of the sample; L is the length of the sample after stretching to a certain elongation; and L1 is the length of the sample after resetting.

[0072] Example 1

[0073] (1) The polyamide 56 resin and the polyamide 6 resin are heated to a molten state respectively to form two polyamide melts;

[0074] (2) The two polyamide melts are respectively conveyed to the spinning box through the melt pipeline, accurately metered by the metering pump, and injected into the spinning assembly to form primary filaments from the spinneret holes, wherein a single suction device is arranged below each spinneret plate;

[0075] (3) The two primary filaments are respectively cooled, oiled, stretched, and wound to obtain two polyamide pre-oriented yarns.

[0076] The temperature of the spinning beam for the polyamide 56 melt is 280°C, the pressure of the spinning pack is 13 MPa, cooling is performed by means of side air blowing, the air speed of the side air blowing is 0.45 m / s, the air temperature is 18°C, the air humidity is 88%, the oiling rate is 0.45%, and the winding speed is 4500 m / min.

[0077] The temperature of the spinning beam for the polyamide 6 melt is 250°C, the pressure of the spinning pack is 12.5 MPa, cooling is performed by means of side air blowing, the air speed of the side air blowing is 0.42 m / s, the air temperature is 19°C, the air humidity is 85%, the oiling rate is 0.46%, and the winding speed is 4300 m / min.

[0078] (4) The two polyamide pre-oriented yarns are combined together in a ratio and are then texturized, i.e. the pre-oriented yarns are first guided through a guide and a first roller, are then heat stretched in a heat chamber, are then cooled and set by means of a cooling plate and are then false twisted, are then guided through a tension on-line detector, are then guided through a second roller, are then provided with a network by means of a network nozzle, are then guided through a third roller, a filament breaking sensor and an oil wheel, and are then wound up, to obtain a polyamide texturized yarn, i.e. a polyamide composite fiber.

[0079] The friction plate for the false twisting is selected from a C-type disc, the temperature of the heat chamber is 175°C, the heat stretching multiple is 1.25, the D / Y ratio for the false twisting is 1.9, the T2 processing tension for the false twisting is controlled to be 1.05 times the Tl tension, and the winding speed is 600 m / min.

[0080] The mass ratio of the polyamide 56 pre-oriented yarn to the polyamide 6 pre-oriented yarn is 50:50.

[0081] The end amino group content of the polyamide 56 pre-oriented yarn is 85 mmol / kg, and the relative viscosity is 2.73.

[0082] The end amino group content of the polyamide 6 pre-oriented yarn is 40 mmol / kg, and the relative viscosity is 2.55.

[0083] The gauge of the polyamide 56 pre-oriented yarn is 53 dtex / 24 f, and the gauge of the polyamide 6 pre-oriented yarn is 53 dtex / 24 f.

[0084] The gauge of the polyamide 56 texturized yarn and the gauge of the polyamide 6 texturized yarn are both 44 dtex / 24 f, and the gauge of the polyamide composite fiber is 88 dtex / 48 f.

[0085] Example 2

[0086] The polyamide composite fiber is prepared according to the same process as in Example 1, except that the end amino group content of the polyamide 56 pre-oriented yarn is controlled to be 95 mmol / kg, and the end amino group content of the polyamide 6 pre-oriented yarn is controlled to be 43 mmol / kg.

[0087] Example 3

[0088] The polyamide composite fiber was prepared according to the same process as in Example 1, except that the end amino group content of the polyamide 56 pre-oriented yarn was controlled to be 105 mmol / kg and the end amino group content of the polyamide 6 pre-oriented yarn was controlled to be 45 mmol / kg.

[0089] Example 4

[0090] The polyamide composite fiber was prepared according to the same process as in Example 2, except that the relative viscosity of the polyamide 56 pre-oriented yarn was controlled to be 2.50 and the relative viscosity of the polyamide 6 pre-oriented yarn was controlled to be 2.55.

[0091] Example 5

[0092] The polyamide composite fiber was prepared according to the same process as in Example 2, except that the relative viscosity of the polyamide 56 pre-oriented yarn was controlled to be 2.65 and the relative viscosity of the polyamide 6 pre-oriented yarn was controlled to be 2.55.

[0093] Example 6

[0094] The polyamide composite fiber was prepared according to the same process as in Example 1, except that the polyamide 66 resin was used instead of the polyamide 6 resin, and further the end amino group content of the polyamide 56 pre-oriented yarn was controlled to be 85 mmol / kg and the relative viscosity was controlled to be 2.73, and the end amino group content of the polyamide 66 pre-oriented yarn was controlled to be 40 mmol / kg and the relative viscosity was controlled to be 2.5.

[0095] Example 7

[0096] The polyamide composite fiber was prepared according to the same process as in Example 1, except that the polyamide 66 resin was used instead of the polyamide 6 resin, and further the end amino group content of the polyamide 56 pre-oriented yarn was controlled to be 95 mmol / kg and the relative viscosity was controlled to be 2.73, and the end amino group content of the polyamide 66 pre-oriented yarn was controlled to be 43 mmol / kg and the relative viscosity was controlled to be 2.5.

[0097] Example 8

[0098] The polyamide composite fiber was prepared according to the same process as in Example 2, except that the mass ratio of the polyamide 56 pre-oriented yarn to the polyamide 6 pre-oriented yarn was controlled to be 50:50.

[0099] The polyamide 56 pre-oriented yarn had a size of 53 dtex / 36 f and the polyamide 6 pre-oriented yarn had a size of 53 dtex / 36 f.

[0100] The specifications of the polyamide 56 drawn yarn and the polyamide 6 drawn yarn are 44 dtex / 36 f and 44 dtex / 36 f respectively, and the specification of the polyamide composite fiber is 88 dtex / 72 f.

[0101] Example 9

[0102] The polyamide composite fiber is prepared according to the same process as that of Example 2, except that the mass ratio of the polyamide 56 pre-oriented yarn to the polyamide 6 pre-oriented yarn is controlled to be 50:50.

[0103] The specification of the polyamide 56 pre-oriented yarn is 40 dtex / 24 f, and the specification of the polyamide 6 pre-oriented yarn is 40 dtex / 24 f.

[0104] The specifications of the polyamide 56 drawn yarn and the polyamide 6 drawn yarn are 33 dtex / 24 f and 33 dtex / 24 f respectively, and the specification of the polyamide composite fiber is 66 dtex / 48 f.

[0105] Example 10

[0106] The polyamide composite fiber is prepared according to the same process as that of Example 1, except that the polyamide 510 resin is used instead of the polyamide 6 resin, and further the preparation process is controlled so that the end amino group content of the polyamide 56 pre-oriented yarn is 85 mmol / kg, and the relative viscosity is 2.73; and the end amino group content of the polyamide 510 pre-oriented yarn is 40 mmol / kg, and the relative viscosity is 2.45.

[0107] Example 11

[0108] The polyamide composite fiber is prepared according to the same process as that of Example 1, except that the polyamide 510 resin is used instead of the polyamide 6 resin, and further the preparation process is controlled so that the end amino group content of the polyamide 56 pre-oriented yarn is 95 mmol / kg, and the relative viscosity is 2.73; and the end amino group content of the polyamide 510 pre-oriented yarn is 43 mmol / kg, and the relative viscosity is 2.45.

[0109] Example 12

[0110] The polyamide composite fiber is prepared according to the same process as that of Example 1, except that the preparation process is controlled so that the end amino group content of the polyamide 56 pre-oriented yarn is 45 mmol / kg, and the relative viscosity is 2.73; and the end amino group content of the polyamide 6 pre-oriented yarn is 40 mmol / kg, and the relative viscosity is 2.55.

[0111] Example 13

[0112] The polyamide composite fiber was prepared according to the same process as in Example 1, except that the polyamide 66 resin was used instead of the polyamide 56 resin, and further, by controlling the preparation process, the end amino group content of the polyamide 56 pre-oriented yarn was 45 mmol / kg, and the relative viscosity was 2.73; the end amino group content of the polyamide 66 pre-oriented yarn was 40 mmol / kg, and the relative viscosity was 2.5.

[0113] Example 14

[0114] The polyamide composite fiber was prepared according to the same process as in Example 1, except that the polyamide 66 resin was used instead of the polyamide 56 resin, and further, by controlling the preparation process, the end amino group content of the polyamide 56 pre-oriented yarn was 45 mmol / kg, and the relative viscosity was 2.55; the end amino group content of the polyamide 66 pre-oriented yarn was 40 mmol / kg, and the relative viscosity was 2.5.

[0115] The polyamide drawn textured yarn prepared in the above examples was dyed with an acid dye, and the dyeing effect is shown in Table 1.

[0116] The performance indexes of the polyamide drawn textured yarn prepared in the above examples are shown in Table 1.

[0117]

[0118] As shown in Table 1, by selecting polyamide fibers with different end amino group contents, relative viscosities, and specifications for compounding, the polyamide composite fiber prepared has good double-color or multi-color effect, low shrinkage, high elastic and fluffy effect, and also has good mechanical properties, evenness, and dyeing performance.

[0119] The above describes the preferred embodiments of the present application in detail, but the present application is not limited thereto. Within the technical concept of the present application, the technical solutions of the present application can be variously modified, including that the various technical features are combined in any other suitable manner, and these simple modifications and combinations should also be considered as the disclosed content of the present application, and all belong to the protection scope of the present application.

Claims

1. A polyamide composite fiber, characterized by, The polyamide composite fiber comprises a first component and a second component, the first component is a polyamide 56 fiber, and the second component is other polyamide fiber selected from at least one of polyamide 6 fiber, polyamide 66 fiber and polyamide 510 fiber; The end amino group content of the first component polyamide 56 fiber is 85-105 mmol / kg, and the relative viscosity of the first component polyamide 56 fiber is 2.6-2.8; the end amino group content of the second component other polyamide fiber is 40-45 mmol / kg, and the relative viscosity of the second component other polyamide fiber is 2.3-2.6; The preparation method of the polyamide composite fiber comprises: (1) heating polyamide 56 resin and other polyamide resin to a molten state respectively to form two polyamide melts; (2) respectively conveying the two polyamide melts to a spinning box through respective melt pipelines, accurately metering through a metering pump, and then injecting into a spinning assembly to form primary fibers through a spinneret hole, wherein a single suction device is arranged below each spinneret plate; (3) respectively cooling, oiling, stretching and winding the two primary fibers to obtain two polyamide fibers; or respectively cooling, oiling and stretching the two primary fibers, and then winding together in proportion to obtain a ply polyamide fiber; (4) adding elasticity to the two polyamide fibers together in proportion, or directly adding elasticity to the ply polyamide fiber to obtain a polyamide composite fiber.

2. The polyamide conjugate fiber according to claim 1, characterized by The mass ratio of the polyamide 56 fiber to the other polyamide fiber is 20:80-80:

20.

3. The polyamide composite fiber according to claim 1 or 2, characterized in that, The relative viscosity of the second component other polyamide fiber is 2.35-2.58; and / or, The mass ratio of the polyamide 56 fiber to the other polyamide fiber is 30:70-70:

30.

4. The polyamide composite fiber according to claim 1, characterized by, The mass ratio of the polyamide 56 fiber to the other polyamide fiber is 40:60-60:40; and / or, The relative viscosity of the second component other polyamide fiber is 2.4-2.

55.

5. The polyamide composite fiber according to claim 1, characterized by, The fineness of the first component polyamide 56 fiber or the second component other polyamide fiber is 10-150 dtex; and / or, The number of pores of the first component polyamide 56 fiber or the second component other polyamide fiber is 7-192 f.

6. The polyamide composite fiber according to claim 1, characterized by The breaking strength of the polyamide composite fiber is ≥3.0 cN / dtex; and / or, The unevenness of the polyamide composite fiber is ≤1.3%; and / or, The elongation at break of the polyamide composite fiber is ≤90%; and / or, The initial modulus of the polyamide composite fiber is ≤40 cN / dtex; and / or, The boiling water shrinkage of the polyamide composite fiber is ≤12%; and / or, The crimp shrinkage of the polyamide composite fiber is ≥35%; and / or, The soaping fastness of the polyamide composite fiber: the color fading fastness is ≥3.5 grade; the color staining fastness is ≥3.5 grade; and / or, The 15% elongation elastic recovery rate of the polyamide composite fiber is ≥92%; and / or, The polyamide composite fiber comprises one or more of non-drawing yarn, pre-oriented yarn, high-oriented yarn, fully-oriented yarn, fully-drawing yarn and elastic yarn.

7. The polyamide conjugate fiber according to claim 1, wherein a fineness of the first component polyamide 56 fiber or the second component other polyamide fiber is 20-120 dtex; and / or, a number of pores of the first component polyamide 56 fiber or the second component other polyamide fiber is 12-144 f; and / or, a breaking strength of the polyamide composite fiber is ≥ 3.2 cN / dtex; and / or, a breaking elongation of the polyamide composite fiber is ≤ 85%; and / or, an initial modulus of the polyamide composite fiber is ≤ 35 cN / dtex; and / or, a boiling water shrinkage of the polyamide composite fiber is ≤ 11%; and / or, a crimping shrinkage of the polyamide composite fiber is ≥ 40%; and / or, a soaping fastness of the polyamide composite fiber: a color fading fastness is ≥ 4.0 grade; a color staining fastness is ≥ 4.0 grade; and / or, a 15% fixed elongation elastic recovery rate of the polyamide composite fiber is ≥ 94%; and / or, the polyamide composite fiber is a pre-oriented yarn, a draw textured yarn or a fully drawn yarn. a fineness of the first component polyamide 56 fiber or the second component other polyamide fiber is 30-90 dtex; and / or, 8. The polyamide conjugate fiber according to claim 1, wherein a number of pores of the first component polyamide 56 fiber or the second component other polyamide fiber is 18-96 f; and / or, a breaking strength of the polyamide composite fiber is ≥ 3.4 cN / dtex; and / or, a breaking elongation of the polyamide composite fiber is ≤ 80%; and / or, an initial modulus of the polyamide composite fiber is ≤ 33 cN / dtex; and / or, a boiling water shrinkage of the polyamide composite fiber is ≤ 10%; and / or, a crimping shrinkage of the polyamide composite fiber is ≥ 45%; and / or, a soaping fastness of the polyamide composite fiber: a color fading fastness is ≥ 4.5 grade; a color staining fastness is ≥ 4.5 grade; and / or, a 15% fixed elongation elastic recovery rate of the polyamide composite fiber is ≥ 95%. a temperature of the spinning beam is 245-300 ℃; and / or, a pressure of the spinning assembly is 10-18 MPa; and / or, 9. The polyamide conjugate fiber according to claim 1, wherein the cooling is cooling by side blowing, a wind speed of the side blowing is 0.3-0.5 m / s; a wind temperature of the side blowing is 16-22 ℃; and / or, a humidity of the side blowing is 75-95%; and / or, an oiling rate of the oiling is 0.4-0.55%; and / or, a winding speed is 4200-5500 m / min. a temperature of the spinning beam is 250-290 ℃; and / or, a pressure of the spinning assembly is 12-16 MPa; and / or, 10. The polyamide conjugate fiber according to claim 9, characterized by a wind speed of the side blowing is 0.4-0.45 m / s; and / or, a wind temperature of the side blowing is 18-20 ℃; and / or, a humidity of the side blowing is 80-90%; and / or, an oiling rate is 0.45-0.5%; and / or, a winding speed is 4300-5000 m / min. ​ ​ 11. The polyamide conjugate fiber according to claim 1, wherein In step (4), the texturing includes the following steps: the polyamide fibers pass through a guide, a first roller, a heat box for heat stretching, a cooling plate for cooling and setting, a false twist, a tension on-line detector, a second roller, a network nozzle, a third roller, a filament breaking sensor, oiling, and winding to obtain the polyamide composite fibers; wherein, the friction sheet for the false twist is selected from a C-shaped disc, a D-shaped disc, and a PU-shaped disc; and / or, the temperature of the heat box is 155-200℃; and / or, the multiple of the heat stretching is 1.20-1.40; and / or, the D / Y ratio of the false twist is 1.6-2.2; and / or, the T2 processing tension of the false twist is controlled to be 0.8-1.1 times of the T1 tension; and / or, the winding speed is 500-800 m / min.

12. The polyamide conjugate fiber according to claim 11, characterized by the friction sheet for the false twist is a C-shaped disc; and / or, the temperature of the heat box is 160-195℃; and / or, the multiple of the heat stretching is 1.23-1.35; and / or, the D / Y ratio of the false twist is 1.65-2.1; and / or, the T2 processing tension of the false twist is controlled to be 0.85-1.05 times of the T1 tension; and / or, the winding speed is 550-750 m / min.

13. The polyamide conjugate fiber according to claim 11, wherein the temperature of the heat box is 165-190℃; and / or, the multiple of the heat stretching is 1.25-1.32; and / or, the D / Y ratio of the false twist is 1.7-2.0; and / or, the T2 processing tension of the false twist is controlled to be 0.9-1.0 times of the T1 tension; and / or, the winding speed is 600-700 m / min.

14. A bicolored or multicolored polyamide composite fiber, characterized by, The polyamide composite fibers according to any one of claims 1-8 are dyed with dyes to obtain polyamide composite fibers with double or multiple colors.

15. The conjugated fiber according to claim 14, wherein The dyes include acid dyes, reactive dyes, neutral dyes, direct dyes, metal complex dyes, vegetable dyes, and disperse dyes.

16. The conjugated fiber according to claim 14, wherein The dyes are acid dyes, reactive dyes, neutral dyes, or metal complex dyes.

17. Use of the polyamide composite fibers according to any one of claims 1-8 in the field of knitted and woven fabrics.

Images