JP7702939B2 - Polyamide islands-in-the-sea fiber, its preparation method, and its use - Google Patents

Description

The present invention belongs to the technical field of polyamide materials and relates to polyamide island-in-the-sea fibers, their production method and their use.

Island-in-sea composite fibers, also known as hyperconjugate fibers, are formed by embedding a very fine form (fibril) of a polymer in another polymer (matrix). They are also called islands-in-sea fibers because the dispersed phase (fibril) is in the form of islands in the fiber cross section. Ultra-fine fibers are obtained by dissolving the sea component from the islands-in-sea fibers. According to the distribution rules, islands-in-sea fibers can be divided into two types, namely fixed islands-in-sea fibers and non- fixed islands-in-sea fibers. Fixed islands-in-sea fibers are uniform and immobile in terms of island distribution, and are generally spun by a conjugate spinning method, i.e., two polymers are spun through a melt conjugate spinning machine and a special spin pack, where one component is uniformly distributed as islands in another polymer (sea component). The islands of non- fixed islands fibers are not fixed and are not sufficiently uniform. The fineness of non- fixed islands fibers varies greatly. The thinnest non- fixed island fibers are thinner than fixed island fibers, but thicker non- fixed island fibers can have a fineness of 0.1 dtex or more. Non- fixed island fibers are mainly produced by blending. The sea part in islands-in-sea composite fibers is a water-soluble polymer. The sea part is dissolved in water by hydrolysis and removed to obtain isolated island parts. In this way, ultra-fine fibers with a linear density of 0.03 to 0.3 dtex are formed, which are mainly used in pseudo-suede materials. Also, when the island parts dissolve, they become hollow fibers, which are mainly used in adsorbents.

The ultra-fine characteristics of sea-island fiber provide excellent properties not found in conventional fibers: 1. soft and delicate touch, significantly reduced bending stiffness, 2. good softness and improved bending stiffness, 3. soft luster and increased diffused light, 4. high cleaning ability, increased contact area, 5. high water and oil absorption, 6. high density structure, 7. strong insulation, retaining more air.

The products have the properties of natural leather (such as moisture absorption, softness, and comfort) and the advantages of good chemical resistance, good physical properties, waterproofness, and light weight. They are mainly used in clothing, household textiles, industrial applications, and other fields. In clothing, they include imitation wool, imitation silk, imitation leather, imitation peach skin, imitation suede, high-density waterproof cloth, insulation materials, safety shoes, etc. In the field of household textiles, they include high-performance cleaning clothing, sofa cloths, curtain cloths, cases, etc. In the field of industrial applications, they include electronic product protective equipment, automobile accessories, high-performance adsorption and filtration materials, high oil absorption materials, and high water absorption materials.

Sea-island composite fibers have a low linear density, a large specific surface area, and can absorb more dyes quickly, resulting in a small fiber radius. Therefore, the distance that the dye diffuses into such fibers is short, the diffusion time is short, and the dye is easy to penetrate deeply. In addition, the fibers have a high content of amorphous regions and the dye is fast, which leads to poor dyeing uniformity in sea-island fibers. Ultrafine fibers have a large surface area and are not sufficiently smooth, so a large amount of dye is used, and the large amount of dyeing dye is difficult to remove by washing. Therefore, the wet fastness of the dye on ultrafine fiber fabrics is lower than that on conventional fibers.

CN106987923A discloses that the stock solution dyed black sea-island fiber. The black sea-island fiber dyed with the stock solution is used to solve the problem that the sea-island fiber is difficult to dye deeply and has poor color fastness. The fiber includes a sea component and an island component. The island component includes 1-60% by weight of black master batch and 10-90% by weight of polyamide 6 or polyester; the sea component is an alkali-soluble polyester; after splitting, the fineness is less than 0.08 dtex, the blackness L value is less than 15, and the color fastness is 4 grades or more. The sea-island fiber is black and the color is too monochromatic, so the applications are limited.

CN106435821A discloses blended or melted sea-island fiber, ultrafine fiber, and preparation method thereof, in which the island component is polyamide and the sea component is water-soluble polyester compound, and the method includes blending, melting and spinning polyamide and water-soluble polyester, placing the sea-island fiber in hot water, and performing a water-lightweighting treatment to remove the sea component polyester, to obtain polyamide ultrafine fiber. In the embodiment, the island component is selected from polyamide 6 and polyamide 66, and the sea component is selected from water-soluble polyester. The sea-island fiber is prepared by a blended spinning method, in which the island component is used as a dispersed phase and the sea component is used as a matrix. The blending during the process is non-uniform, which results in non-uniform distribution of the island component. The components have a large difference in thickness when split, which affects the subsequent dyeing and causes color difference.

The first object of the present invention is to provide a polyamide sea-island fiber that simultaneously has better mechanical properties, better flexibility and good dyeability.

The second object of the present invention is to provide a method for producing polyamide islands-in-the-sea fiber, which uses materials from non-petroleum-based sources (i.e., bio-based sources) that do not cause serious pollution and are beneficial to environmental protection.

The third object of the present invention is to provide a use of polyamide sea-island fiber.

To achieve the above objective, the present invention provides the following solutions:

[Polyamide Island-in-the-Sea Fiber]
The present invention provides a polyamide islands-in-the-sea fiber, wherein the island component is a polyamide resin selected from one of polyamide 56, polyamide 510, polyamide 511, polyamide 512, polyamide 513, polyamide 514, polyamide 515 and polyamide 516, preferably polyamide 56 or polyamide 510, and the sea component is one of polyethylene, low density polyethylene, polystyrene, water soluble polyester, polyester and polyurethane, preferably polyethylene, low density polyethylene or water soluble polyester.

The island component can be super bright (SB) polyamide resin, semi-dull (SD) polyamide resin, full-dull (FD) polyamide resin and mixtures thereof.

In some preferred embodiments of the present invention, the island component polyamide resin has a relative viscosity of 2.4 to 3.0, preferably 2.5 to 2.9, more preferably 2.6 to 2.8; and/or the mass ratio of island component to sea component of the sea-island fiber is 20-80:80-20, more preferably 30-70:70-30.

In some preferred embodiments of the present invention, the islands-in-sea fiber includes fixed island-type islands-in-sea fiber and non- fixed island-type islands-in-sea fiber; and/or the number of islands in the fixed island-type islands-in-sea fiber is 16 to 500;

In some preferred embodiments of the present invention, the polyamide islands-in-the-sea fiber has a fineness of 10-300 dtex, preferably 20-200 dtex, more preferably 30-100 dtex, and/or the polyamide islands-in-the-sea fiber has a breaking strength of 2.0-5.0 cN/dtex, preferably 2.5-4.5 cN/dtex, more preferably 3.0-4.0 cN/dtex, and/or the polyamide islands-in-the-sea fiber has a breaking strength of 30-80%, preferably 30-50%. and/or the polyamide island-sea fiber has an initial modulus of 20-50 cN/dtex, preferably 23-45 cN/dtex, more preferably 28-38 cN/dtex, and/or after the polyamide island-sea fiber is split, the polyamide island-sea fiber has an initial modulus of 0.001-0.2 dtex, preferably 0.005-0.1 dtex, more preferably 0.01- and/or the polyamide islands-in-the-sea fiber has a K/S value of 15 or more, preferably 20 or more, more preferably 25 or more; and/or the polyamide islands-in-the-sea fiber has a dye uptake of 90% or more, preferably 93% or more, more preferably 96% or more; and/or the polyamide islands-in-the-sea fiber has a dye uniformity (gray scale) of Grade 3.5 or more, preferably 4.0 or more, more preferably 4.5 or more; and/or the polyamide islands-in-the-sea fiber has a soap fastness to fading of Grade 3.0 or more, preferably Grade 3.5 or more, more preferably Grade 4.0 or more, even more preferably Grade 4.5 or more; and/or the polyamide islands-in-the-sea fiber has a soap fastness to dyeing of Grade 3.0 or more, preferably Grade 3.5 or more, more preferably Grade 4.0 or more, even more preferably Grade 4.5 or more.

The present invention provides a method for producing the above fixed island type sea-island fiber, the method comprising the steps of:
1) The island component resin and the sea component resin are heated and melted to obtain two melts. The two melts are transported to the spin beam through pipes. Each melt is precisely metered by a metering pump and injected into an islands-in-the-sea composite spin pack by the spin beam. The two melts are distributed through distribution pipes in the spin pack and are converged at the entrance of the spinneret orifice and extruded. Here, the island component has a moisture content of less than 1500 ppm, and the sea component has a moisture content of less than 300 ppm.

2) The as-formed fiber extruded in step 1) is cooled, spin-finished, drawn, heat-set and wound up to obtain fixed island-island-in-the-sea fiber.

The heating in step 1) is carried out in a screw extruder, which preferably contains five zones for heating;
For the island component screw, the temperature of the first zone is 200-260°C, the temperature of the second zone is 230-280°C, the temperature of the third zone is 240-290°C, the temperature of the fourth zone is 260-300°C, and the temperature of the fifth zone is 270-310°C; and/or for the sea component screw, the temperature of the first zone is 120-220°C, the temperature of the second zone is 140-240°C, the temperature of the third zone is 160-260°C, the temperature of the fourth zone is 180-280°C, and the temperature of the fifth zone is 160-290°C. For the islands-in-sea fiber, the rational adjustment of the temperature of the two melts is the key to control the cross-sectional shape of the two components after they are conjugated. If the temperature is too high or too low, the cross-sectional shape of the as-formed yarn will change, and the uniformity of the cross-sectional shape will also decrease. In general, the difference in melt viscosity of the two polymers will affect the cross-sectional shape. If the viscosities of the two melts are significantly different, it will affect the uniformity of the cross-sectional shape and the islands will even adhere together or even form a "solid" body. This will make the islands unable to be separated during post-split processing. Therefore, a suitable spinning temperature should be selected during spinning. This method is adjusted to ensure that the spinning temperature falls within the above-mentioned temperature range and that the melt viscosities of the sea and island components match each other.

In step 1), the temperature of the spinning beam is controlled to 200-300°C; the spinning pack pressure of the island component is controlled to 10.0-15.0 MPa; the spinning pack pressure of the sea component is controlled to 8.0-15.0 MPa; and the spinning pack pressure difference between the sea component and the island component is controlled to 4.0 MPa or less.

In step 2), the cooling is performed by quench air or cross air blowing, the air speed is 0.2-1.2 m/s, preferably 0.2-1.0 m/s, more preferably 0.3-0.8 m/s, the air temperature of the quench air is 15-30° C., preferably 20-27° C., more preferably 22-25° C., and/or the oil pick-up is 0.2-1.0 wt.%, preferably 0.3-0.8 wt.%, more preferably 0.4-0.6 wt.%, the oil pick-up being calculated based on the weight of the fiber. and/or the drawing process is that the spin-finished as-laid yarn is passed through a draw feed roller to a hot draw roller, the draw ratio is preferably 2.0-5.0, more preferably 2.5-3.0; and/or the heat-setting temperature is 150-220°C, preferably 160-200°C, more preferably 170-180°C; and/or the take-up speed is 1000-6000 m/min, preferably 2000-5000 m/min, more preferably 2500-4000 m/min.

In some preferred embodiments of the present invention, the method further comprises splitting the islands-in-sea fiber obtained in step 2) in a solvent to remove the sea component;
The solvent is toluene, xylene and a 1-10 wt% aqueous solution of sodium hydroxide; the split temperature is 60-100°C, preferably 65-95°C, more preferably 75-85°C; the split time is 10-70min, preferably 20-60min, more preferably 30-50min; the liquor ratio is 1:10-1:80, preferably 1:20-1:60, more preferably 1:30-1:40; and/or the sea-island fiber weight loss is 20-50wt%, preferably 25-45wt%, more preferably 30-40wt%.

The present invention provides a method for producing the above non- fixed island type sea-island fiber, comprising the steps of:
a) homogeneously mixing island and sea components in a certain ratio, then heating and melting the mixture; conveying the resulting blended melt through a pipe to a spin beam; precisely metering the blended melt by a metering pump and injecting it into a one-component spin pack in the spin beam; extruding the blended melt through a spinneret orifice; wherein the island components have a moisture content of less than 1500 ppm; and the sea component has a moisture content of less than 300 ppm;

2) The extruded as-formed fiber is cooled, spin-finished, drawn, heat-set and wound to obtain the non- fixed island-in-the-sea fiber.

In step a), the heating is carried out in a screw extruder, where the screw extruder preferably comprises five zones for heating; the temperature of the first zone is 180-240°C; the temperature of the second zone is 200-260°C; the temperature of the third zone is 220-270°C; the temperature of the fourth zone is 240-280°C; and the temperature of the fifth zone is 200-300°C.

In step a), the temperature of the spinning beam is 200-300°C and the spinning pack pressure is 10.0-25.0 MPa.

In step b), the cooling is performed by quench air or cross air blowing, the air speed is 0.2-1.2 m/s, preferably 0.4-1.0 m/s, more preferably 0.6-0.8 m/s, the air temperature of the quench air is 15-30° C., preferably 23-27° C., more preferably 24-25° C., and/or the oil pickup is 0.2-1.0 wt. %, preferably 0.3-0.8 wt. %, more preferably 0.4-0.6 wt. %, and/or the drawing process is The process is that the spin-finished as-formed yarn is directed through draw feed rollers to hot draw rollers, with a draw ratio of preferably 2.0-5.0, more preferably 2.5-3.0; and/or the heat-setting temperature is 150-220°C, preferably 160-200°C, more preferably 170-180°C; and/or the take-up speed is 1000-6000 m/min, preferably 2000-5000 m/min, more preferably 2500-4000 m/min.

In some preferred embodiments of the present invention, the method further comprises splitting the islands-in-the-sea fiber obtained in step b) in a solvent to remove the sea component;
The solvent is toluene, xylene and a 1-10 wt% aqueous solution of sodium hydroxide; the split temperature is 60-100°C, preferably 65-95°C, more preferably 75-85°C; the split time is 10-70min, preferably 20-60min, more preferably 30-50min; the liquor ratio is 1:10-1:80, preferably 1:20-1:60, more preferably 1:30-1:40; and/or the sea-island fiber weight loss is 20-50wt%, preferably 25-45wt%, more preferably 30-40wt%.

[Use of polyamide island-in-the-sea fiber]
Polyamide sea-island fibers include filaments and staple fibers, and are mainly used in the manufacturing fields of imitation wool, imitation silk, imitation leather, imitation peach skin, imitation suede, high-density waterproof fabrics, high-performance washable clothing, high-performance adsorption and filtration materials, highly oil-absorbent materials, highly water-absorbent materials, heat insulating materials, medical materials, automotive equipment materials, safety shoes, cases, handbags, sofas, etc.

The fabric made of the polyamide sea-island fiber of the present invention is soft to the touch, has good penetration resistance, and has good dyeability, compared with conventional sea-island fabrics. Such fabric is more suitable for wiping cloths. It produces good effect and is less likely to damage the surface of the object being wiped. The excellent complete dull effect that such fabric has is well reflected in fabrics for down jackets and nurse uniforms. Furthermore, when such fibers are split, they can produce ultra-fine yarns that are smaller in fineness, soft to the touch, and have less penetration resistance, compared with conventional sea-island ultra-fine yarns. This manufacturing method is simple and easy to operate.

By adopting the above technical solutions, the present invention has the following advantages compared with the prior art:

Firstly, the raw material for the island components of the polyamide sea-island fiber of the present invention is prepared by a biological process, making it a green material that does not depend on petroleum resources and does not cause serious environmental pollution. It also reduces carbon dioxide emissions and the greenhouse effect.

Second, the polyamide sea-island fiber of the present invention has better mechanical properties and is softer.

Third, the polyamide sea-island fiber of the present invention has good dyeability, high grade dyeing gray scale, high dye uptake, high dye depth and high color fastness.

Finally, the polyamide sea-island fiber of the present invention has a monofilament fineness of 0.01 to 0.2 dtex after splitting. The monofilaments are fine, and the fibers have a soft and delicate touch. The bending stiffness is significantly reduced, and the luster is soft. The fibers have a large specific surface area and a high density structure. They are more suitable for use in fields such as imitation wool, imitation silk, imitation leather, imitation peach skin, imitation suede, high-density waterproof cloth, high-performance washable clothing, high-performance adsorption and filtration materials, high oil absorption materials, high water absorption materials, insulation materials, medical materials, automotive equipment materials, safety shoes, protective equipment for electronic products, cases, handbags, sofas, etc.

In order to make the objectives, technical solutions and advantages of the present disclosure clearer, the technical solutions of the present disclosure are clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by those skilled in the art based on the embodiments in the present disclosure and without creative work shall fall within the protection scope of the present disclosure.

(1) Fineness:
The fineness is measured according to GB/T 14343.
(2) Breaking strength:
The breaking strength is measured according to GB/T 14344-2008.
(3) Elongation at break:
Elongation at break is measured according to GB/T 14344-2008.

(4) Initial elastic modulus:
The initial modulus is measured according to GB/T 14344. The initial modulus is defined as the breaking strength corresponding to an elongation at break of 1%.

(5) Weight loss Weight loss (wt%) = (fiber weight before splitting - fiber weight after splitting) / fiber weight before splitting x 100%;

(6) Dyeing uniformity (gray card)/grade:
Dye uniformity is measured according to FZ/T 50008 test method for dye uniformity of polyamide filaments.

(7) K/S value:
The K/S value of dyed fabrics is measured by computer color measurement and color matching equipment. The K/S value represents the apparent color depth value.
In the formula, S represents the dispersion coefficient, K represents the absorption coefficient, and R represents the reflectance.

(8) Dye uptake:
The difference in the concentration of the dye solution before and after dyeing is measured using a spectrophotometer.
Dye uptake (%)=(A ₀ −A _t )/A ₀ ×100%;
where A ₀ represents the absorbance value of the characteristic absorption peak of the dye before treatment and A _t represents the absorbance value of the dye at treatment time t.

(9) Soap fastness:
Soap fastness is measured according to national standard GB/T3921.1-1997.

(10) Relative Viscosity:
The relative viscosity of polyamide 5X resin is measured with concentrated sulfuric acid using an Ubbelohde viscometer. The procedure is as follows: precisely weigh out 0.25±0.0002 g of dried polyamide 5X resin sample; add 50 mL of concentrated sulfuric acid (96%) to dissolve. Measure and record the flow time t ₀ of concentrated sulfuric acid and the flow time t of the solution of polyamide 5X continuous bulk filament in a water bath at a constant temperature of 25° C.
The relative viscosity is calculated according to the following formula:
Relative viscosity VN=t/t ₀ ;
t represents the flow time of the solution, and t ₀ represents the flow time of the solvent.

(11) Moisture content:
The water content is measured by a Karl Fischer water titrator.

Water-soluble polyester COPET is commercially available from Puyuan Chemical Fiber Co., Ltd. (Shanghai). The polyester COPET is fiber grade and has an intrinsic viscosity of 0.6-0.8. Polyamide 56 chips with a relative viscosity of 2.4-3.0 are commercially available from Kaisai (Jinxiang) Biomaterials Co., Ltd. Polyamide 6 chips with a relative viscosity of 2.5-2.7 are commercially available from Ruimeifu Industrial Co., Ltd. (Jiangsu). Polyamide 66 chips with a relative viscosity of 2.4-2.7 are commercially available from Shenma Plastic Technology Co., Ltd. (Pingdingshan). Polyethylene resins with melt indexes of 10-80 g/10 min are commercially available from Yanshan Petrochemical Co., Ltd. (Beijing).

Example 1
This example provides a method for producing polyamide 56/polyethylene islands-in-the-sea fiber, which includes the following steps:
1) Drying the island component polyamide 56 resin and the sea component polyethylene resin, respectively; after drying, the moisture content of the island component is controlled to 800 ppm, and the moisture content of the sea component is adjusted to 60 ppm;

2) Heat and melt the island component resin and the sea component resin in a certain ratio, where the mass ratio of the island component to the sea component in the island-sea fiber is 70:30; transport the above two melts through pipes to the spin beam; precisely meter each melt with a metering pump and inject it into the sea-island composite spin pack in the spin beam; distribute through the distribution pipe in the spin pack, and then converge and extrude the two melts at the entrance of the spinneret orifice; and

3) The extruded as-formed fiber is cooled, spin-finished, drawn, heat-set and wound to obtain fixed island-island-in-the-sea fiber.

The number of islands in the fixed island-sea-island fiber monofilament was 51, and the fiber had a circular cross section.

In step 1), the relative viscosity of the island component polyamide 56 resin was 2.5.

In step 2), the heating was carried out in a screw extruder, which contained five zones for heating:
For the island component screw: first zone temperature was 230°C, second zone temperature was 250°C, third zone temperature was 270°C, fourth zone temperature was 290°C, fifth zone temperature was 285°C;
For the sea component screw: the temperature of the first zone was 120°C, the temperature of the second zone was 140°C, the temperature of the third zone was 160°C, the temperature of the fourth zone was 180°C, and the temperature of the fifth zone was 220°C;

In step 2), the temperature of the spinning beam was 280°C; the spinning pack pressure of the island component was 13.0 MPa; the spinning pack pressure of the sea component was 11.0 MPa; and the spinning pack pressure difference between the sea component and the island component was controlled to 4.0 MPa or less.

In step 3), the cooling was performed by quench air, the air speed was 0.5 m/s, the air temperature was 23° C., and the oil absorption pickup calculated based on the weight of the fiber was 0.3 wt %;
The spin-finished as-formed yarn was passed through a feed roller to a hot draw roller for drawing, with a draw ratio of 3.0, a heat set temperature of 180° C., and a take-up speed of 3500 m/min.

The sea-island fiber split process used xylene as the solvent, a split temperature of 70°C, a split time of 30 minutes, a bath ratio of 1:30, and a fiber weight loss of 29% by weight.

Test data for the resulting sea-island fiber is shown in Table 1.

Example 2
This example provides a method for producing polyamide 56/low density polyethylene islands-in-the-sea fiber, including the following steps:
1) Drying the island component polyamide 56 resin and the sea component low-density polyethylene resin, respectively; after drying, the moisture content of the island component is controlled to 1000 ppm, and the moisture content of the sea component is adjusted to 90 ppm;

2) Heat and melt the island component resin and the sea component resin in a certain ratio, where the mass ratio of the island component to the sea component in the island-sea fiber is 60:40; transport the above two melts through pipes to the spin beam; precisely meter each melt with a metering pump and inject it into the sea-island composite spin pack in the spin beam; distribute it through the distribution pipe in the spin pack, and then converge and extrude the two melts at the entrance of the spinneret orifice; and

3) The extruded as-formed fiber is cooled, spin-finished, drawn, heat-set and wound to obtain fixed island-island-in-the-sea fiber.

The number of islands in the fixed island-sea-island fiber monofilament was 37, and the fiber had a circular cross section.

In step 1), the relative viscosity of the island component polyamide 56 resin was 2.8.

In step 2), the heating was carried out in a screw extruder, which contained five zones for heating:
For the island component screw: 1st zone temperature was 240°C, 2nd zone temperature was 260°C, 3rd zone temperature was 280°C, 4th zone temperature was 290°C, 5th zone temperature was 280°C;
For the sea component screw: the temperature of the first zone was 120°C, the temperature of the second zone was 150°C, the temperature of the third zone was 180°C, the temperature of the fourth zone was 190°C, and the temperature of the fifth zone was 210°C;

In step 2), the temperature of the spinning beam was 270°C; the spinning pack pressure of the island component was 14.0 MPa; the spinning pack pressure of the sea component was 13.0 MPa; and the spinning pack pressure difference between the sea component and the island component was controlled to 4.0 MPa or less.

In step 3), the cooling was performed by quench air, the air speed was 0.3 m/s, the air temperature was 22° C., and the oil pick-up calculated based on the weight of the fiber was 0.6 wt %;
The spin-finished as-formed yarn was passed through a feed roller to a hot draw roller for drawing, with a draw ratio of 3.2, a heat set temperature of 120° C., and a take-up speed of 4000 m/min.

The sea-island fiber split process had a toluene solvent, a split temperature of 80°C, a split time of 40 minutes, a bath ratio of 1:40, and a fiber weight loss of 38% by weight.

Test data for the resulting sea-island fiber is shown in Table 1.

Example 3
This example provides a method for producing polyamide 56/water-soluble polyester island-in-the-sea fiber, which includes the following steps:
1) Drying the island component polyamide 56 resin and the sea component water-soluble polyester resin, respectively; after drying, the moisture content of the island component is controlled to 500 ppm, and the moisture content of the sea component is adjusted to 30 ppm;

2) Heat and melt the island component resin and the sea component resin in a certain ratio, where the mass ratio of the island component to the sea component in the island-sea fiber is 80:20; transport the above two melts through pipes to the spin beam; precisely meter each melt with a metering pump and inject it into the island-in-sea composite spin pack in the spin beam; distribute it through the distribution pipe in the spin pack, and then converge and extrude the two melts at the entrance of the spinneret orifice; and

3) The extruded as-formed fiber is cooled, spin-finished, drawn, heat-set and wound to obtain fixed island-island-in-the-sea fiber.

The number of islands in the fixed island-sea-island fiber monofilament was 37, and the fiber had a circular cross section.

In step 1), the relative viscosity of the island component polyamide 56 resin was 2.8.

In step 2), the heating was carried out in a screw extruder, which contained five zones for heating:
For the island component screw: first zone temperature was 240°C, second zone temperature was 260°C, third zone temperature was 280°C, fourth zone temperature was 290°C, fifth zone temperature was 290°C;
For the sea component screw: the temperature of the first zone was 180°C, the temperature of the second zone was 220°C, the temperature of the third zone was 240°C, the temperature of the fourth zone was 260°C, the temperature of the fifth zone was 240°C;

In step 2), the temperature of the spinning beam was 285°C; the spinning pack pressure of the island component was 14.0 MPa; the spinning pack pressure of the sea component was 13.0 MPa; and the spinning pack pressure difference between the sea component and the island component was controlled to 4.0 MPa or less.

In step 3), the cooling was performed by quench air, the air speed was 0.6 m/s, the air temperature was 25° C., and the oil pick-up calculated based on the weight of the fiber was 0.5 wt %;
The spin-finished as-formed yarn was passed through a feed roller to a hot draw roller for drawing, with a draw ratio of 2.5, a heat set temperature of 160° C., and a take-up speed of 2500 m/min.

The sea-island fiber split process used a 20 wt% aqueous solution of sodium hydroxide as the solvent, a split temperature of 90°C, a split time of 40 minutes, a bath ratio of 1:20, and a fiber weight loss of 19 wt%.

Test data for the resulting sea-island fiber is shown in Table 1.

Example 4
This example provides a method for producing polyamide 510/polyethylene islands-in-the-sea fiber, including the following steps:
1) Drying the island component polyamide 510 resin and the sea component polyethylene resin, respectively; after drying, the moisture content of the island component is controlled to 900 ppm, and the moisture content of the sea component is adjusted to 80 ppm;

2) Heat and melt the island component resin and the sea component resin in a certain ratio, where the mass ratio of the island component to the sea component in the island-sea fiber is 65:35; transport the above two melts through pipes to the spin beam; precisely meter each melt with a metering pump and inject it into the sea-island composite spin pack in the spin beam; distribute it through the distribution pipe in the spin pack, and then converge and extrude the two melts at the entrance of the spinneret orifice; and

3) The extruded as-formed fiber is cooled, spin-finished, drawn, heat-set and wound to obtain fixed island-island-in-the-sea fiber.

The number of islands in the fixed island-sea-island fiber monofilament was 51, and the fiber had a circular cross section.

In step 1), the relative viscosity of the island component polyamide 510 resin was 2.6.

In step 2), the heating was carried out in a screw extruder, which contained five zones for heating:
For the island component screw: 1st zone temperature was 220°C, 2nd zone temperature was 230°C, 3rd zone temperature was 240°C, 4th zone temperature was 260°C, 5th zone temperature was 260°C;
For the sea component screw: the temperature of the first zone was 130°C, the temperature of the second zone was 150°C, the temperature of the third zone was 170°C, the temperature of the fourth zone was 180°C, and the temperature of the fifth zone was 230°C;

In step 2), the temperature of the spinning beam was 255°C; the spinning pack pressure of the island component was 12.0 MPa; the spinning pack pressure of the sea component was 10.0 MPa; and the spinning pack pressure difference between the sea component and the island component was controlled to 4.0 MPa or less.

In step 3), the cooling was performed by quench air, the air speed was 0.8 m/s, the air temperature was 22° C., and the oil pick-up calculated based on the weight of the fiber was 0.4 wt.%;
The spin-finished as-formed yarn was passed through a feed roller towards hot draw rollers for drawing, with a draw ratio of 2.5, a heat set temperature of 130° C. and a take-up speed of 3000 m/min.

The sea-island fiber split process used xylene as the solvent, a split temperature of 70°C, a split time of 30 minutes, a bath ratio of 1:30, and a fiber weight loss of 34% by weight.

Test data for the resulting sea-island fiber is shown in Table 1.

Example 5
This example provides a method for producing polyamide 56/water-soluble polyester non- fixed island-type sea-island fiber, which includes the following steps:
1) Drying the island component resin and the sea component resin, respectively; after drying, the moisture content of the island component is controlled to 800 ppm, and the moisture content of the sea component is adjusted to 90 ppm;

2) After uniformly mixing the island and sea components in a certain ratio, the mixture is heated and melted, where the mass ratio of the island components to the sea components in the island-sea fiber is 70:30, the blended melt is transported to a spinning beam through a pipe, the blended melt is precisely metered by a metering pump and injected into a one-component spin pack in the spinning beam, and the blended melt is extruded through a spinneret orifice; and

3) The extruded as-formed fiber is cooled, spin-finished, drawn, heat-set and wound to obtain the unfixed islands-in-the-sea fiber.

In step 1), the relative viscosity of the island component polyamide 56 resin was 2.7.

In step 2), the heating was carried out in a screw extruder, where the screw extruder contained five zones for heating;
The temperature of the first zone was 220°C, the temperature of the second zone was 240°C, the temperature of the third zone was 260°C, the temperature of the fourth zone was 280°C, and the temperature of the fifth zone was 280°C;

In step 2), the spinning beam temperature was 280°C; the spinning pack pressure was 16.0 MPa.

In step 3), the cooling was performed by quench air, the air speed was 0.4 m/s, the air temperature was 24° C., and the oil pick-up calculated based on the weight of the fiber was 0.3 wt %;
The spin-finished as-formed yarn was passed through a feed roller to a hot draw roller for drawing, with a draw ratio of 3.0, a heat set temperature of 170° C., and a take-up speed of 4200 m/min.

The sea-island fiber split process used a 3.0 wt% aqueous solution of sodium hydroxide as the solvent, a split temperature of 90°C, a split time of 40 minutes, a bath ratio of 1:30, and a fiber weight loss of 28 wt%.

Test data for the resulting sea-island fiber is shown in Table 1.

Example 6
This example provides a method for producing polyamide 510/water-soluble polyester non-island-in-the-sea fiber, which includes the following steps:
1) Drying the island component resin and the sea component resin, respectively; after drying, the moisture content of the island component is controlled to 700 ppm, and the moisture content of the sea component is adjusted to 60 ppm;

2) After the island component and sea component are uniformly mixed in a certain ratio, the mixture is heated and melted, where the mass ratio of the island component to the sea component in the island-sea fiber is 60:40, the blended melt is transported to a spinning beam through a pipe, the blended melt is precisely metered by a metering pump and injected into a one-component spinning pack in the spinning beam, and the blended melt is extruded through a spinneret orifice;

3) The extruded as-formed fiber is cooled, spin-finished, drawn, heat-set and wound to obtain the unfixed islands-in-the-sea fiber.

In step 1), the relative viscosity of the island component polyamide 510 resin was 2.7.

In step 2), the heating was carried out in a screw extruder, which contained five zones for heating:
The temperature of the first zone was 220°C, the temperature of the second zone was 230°C, the temperature of the third zone was 260°C, the temperature of the fourth zone was 270°C, and the temperature of the fifth zone was 280°C;

In step 2), the temperature of the spinning beam was 270°C; the spinning pack pressure was 14.0 MPa.

In step 3), the cooling was performed by quench air, the air speed was 0.6 m/s, the air temperature was 25° C., and the oil pick-up calculated based on the weight of the fiber was 0.5 wt %;
The spin-finished as-formed yarn was passed through a feed roller towards hot draw rollers for drawing, with a draw ratio of 1.5, a heat set temperature of 180° C. and a take-up speed of 4000 m/min.

The sea-island fiber split process used a 5.0 wt% aqueous solution of sodium hydroxide as the solvent, a split temperature of 85°C, a split time of 50 minutes, a bath ratio of 1:20, and a fiber weight loss of 38 wt%.

Test data for the resulting sea-island fiber is shown in Table 1.

Comparative Example 1
This comparative example provides a method for producing polyamide 6/polyethylene islands-in-the-sea fiber, which includes the following steps:
1) Drying the island component polyamide 6 resin and the sea component polyethylene resin, respectively; after drying, the moisture content of the island component is controlled to 800 ppm, and the moisture content of the sea component is adjusted to 60 ppm;

2) Heat and melt the island component resin and the sea component resin in a certain ratio, where the mass ratio of the island component to the sea component in the island-sea fiber is 70:30; transport the above two melts through pipes to the spin beam; precisely meter each melt with a metering pump and inject it into the sea-island composite spin pack in the spin beam; distribute through the distribution pipe in the spin pack, and then converge and extrude the two melts at the entrance of the spinneret orifice; and

3) The extruded as-formed fiber is cooled, spin-finished, drawn, heat-set and wound to obtain fixed island-island-in-the-sea fiber.

The number of islands in the fixed island-sea-island fiber monofilament was 51, and the fiber had a circular cross section.

In step 1), the relative viscosity of the island component polyamide 6 resin was 2.5.

In step 2), the heating was carried out in a screw extruder, where the screw extruder contained five zones for heating;
For the island component screw: first zone temperature was 220°C, second zone temperature was 230°C, third zone temperature was 240°C, fourth zone temperature was 260°C, fifth zone temperature was 275°C;
For the sea component screw: the temperature of the first zone was 120°C, the temperature of the second zone was 140°C, the temperature of the third zone was 160°C, the temperature of the fourth zone was 180°C, and the temperature of the fifth zone was 220°C;

In step 2), the temperature of the spinning beam was 250°C; the spinning pack pressure of the island component was 12.0 MPa; the spinning pack pressure of the sea component was 11.0 MPa; and the spinning pack pressure difference between the sea component and the island component was controlled to 4.0 MPa or less.

In step 3), the cooling was performed by quench air, the air speed was 0.5 m/s, the air temperature was 23° C., and the oil pick-up calculated based on the weight of the fiber was 0.3 wt %;
The spin-finished as-formed yarn was passed through a feed roller to a hot draw roller for drawing, with a draw ratio of 3.0, a heat set temperature of 180° C., and a take-up speed of 3500 m/min.

The sea-island fiber split process used xylene as the solvent, a split temperature of 70°C, a split time of 30 minutes, a bath ratio of 1:30, and a fiber weight loss of 28% by weight.

Test data for the resulting sea-island fiber is shown in Table 1.

Comparative Example 2
This comparative example provides a method for producing polyamide 6/water-soluble polyester non-island-in-the-sea type fiber, which includes the following steps:
1) Drying the island component resin and the sea component resin, respectively; after drying, the moisture content of the island component is controlled to 800 ppm, and the moisture content of the sea component is adjusted to 90 ppm;

2) After uniformly mixing the island and sea components in a certain ratio, the mixture is heated and melted, where the mass ratio of the island components to the sea components in the island-sea fiber is 70:30, the blended melt is transported to a spinning beam through a pipe, the blended melt is precisely metered by a metering pump and injected into a one-component spin pack in the spinning beam, and the blended melt is extruded through a spinneret orifice; and

3) The extruded as-formed fiber is cooled, spin-finished, drawn, heat-set and wound to obtain the unfixed islands-in-the-sea fiber.

In step 1), the relative viscosity of the island component polyamide 6 resin was 2.7.

In step 2), the heating was carried out in a screw extruder, which contained five zones for heating:
The temperature of the first zone was 220°C, the temperature of the second zone was 240°C, the temperature of the third zone was 250°C, the temperature of the fourth zone was 260°C, and the temperature of the fifth zone was 260°C;

In step 2), the temperature of the spinning beam was 260°C; the spinning pack pressure was 12.0 MPa.

In step 3), the cooling was performed by quench air, the air speed was 0.4 m/s, the air temperature was 24° C., and the oil pick-up calculated based on the weight of the fiber was 0.3 wt %;
The spin-finished as-formed yarn was passed through a feed roller to a hot draw roller for drawing, with a draw ratio of 3.0, a heat set temperature of 170° C., and a take-up speed of 4200 m/min.

The sea-island fiber split process used a 3.0 wt% aqueous solution of sodium hydroxide as the solvent, a split temperature of 90°C, a split time of 40 minutes, a bath ratio of 1:30, and a fiber weight loss of 28 wt%.

Test data for the resulting sea-island fiber is shown in Table 1.

Comparative Example 3
This comparative example provides a method for producing polyamide 66/water-soluble polyester non-island-in-the-sea type fiber, which includes the following steps:
1) Drying the island component resin and the sea component resin, respectively; after drying, the moisture content of the island component is controlled to 800 ppm, and the moisture content of the sea component is adjusted to 90 ppm;

2) After uniformly mixing the island and sea components in a certain ratio, the mixture is heated and melted, where the mass ratio of the island components to the sea components in the island-sea fiber is 70:30, the blended melt is transported to a spinning beam through a pipe, the blended melt is precisely metered by a metering pump and injected into a one-component spin pack in the spinning beam, and the blended melt is extruded through a spinneret orifice; and

3) The extruded as-formed fiber is cooled, spin-finished, drawn, heat-set and wound to obtain the unfixed islands-in-the-sea fiber.

In step 1), the relative viscosity of the island component polyamide 66 resin was 2.7.

In step 2), the heating was carried out in a screw extruder, which contained five zones for heating:
The temperature of the first zone was 230°C, the temperature of the second zone was 250°C, the temperature of the third zone was 270°C, the temperature of the fourth zone was 280°C, and the temperature of the fifth zone was 290°C;

In step 2), the temperature of the spinning beam was 290°C; the spinning pack pressure was 13.0 MPa.

In step 3), the cooling was performed by quench air, the air speed was 0.4 m/s, the air temperature was 24° C., and the oil pick-up calculated based on the weight of the fiber was 0.3 wt %;
The spin-finished as-formed yarn was passed through a feed roller to a hot draw roller for drawing, with a draw ratio of 3.0, a heat set temperature of 170° C., and a take-up speed of 4200 m/min.

The sea-island fiber split process used a 3.0 wt% aqueous solution of sodium hydroxide as the solvent, a split temperature of 90°C, a split time of 40 minutes, a bath ratio of 1:30, and a fiber weight loss of 28 wt%.

Test data for the resulting sea-island fiber is shown in Table 1.

Comparative Example 4
This comparative example provides a method for producing polyamide 56/water-soluble polyester fixed island-island-in-sea fiber, which includes the following steps:
Polyamide 56 is used as the island component polymer, and a water-soluble polyester is used as the sea component polymer. They are melted, metered by a metering pump, and fed into a spinning machine at a spinning temperature of 298°C. The overall ratio of the sea component and the island component is set to 20/80. The melt of the sea component and the island component is introduced into a sea-island composite spinning pack, and then extruded from a spinneret. The yarn spun from the spinneret is cooled by an air cooling device. After the yarn is spun, it is wound into an unrefined 175 dtex-112 filament on a winder at a speed of 1500 m/min;
Subsequently, the filaments are drawn in a drawing device at a speed of 300 m/min, and the elongation is controlled at 20 to 40% to obtain a drawn yard of 66 dtex-112 filaments. The obtained islands-in-the-sea type composite fiber is immersed in a 1 wt % aqueous sodium hydroxide solution at 80° C. to remove the sea component by dissolution.

Test data for the resulting sea-island fiber is shown in Table 1.

The polyamide island-sea fibers prepared in Examples 1 to 6 of the present invention had a lower initial modulus than those prepared in Comparative Examples 1 to 3. Therefore, the polyamide island-sea fibers prepared in Examples 1 to 6 had better softness. The polyamide island-sea fibers of the present invention also had good dyeability. The polyamide island-sea fibers prepared in Examples 1 to 6 were significantly better than those prepared in Comparative Examples 1 to 3 in terms of dye uptake, dye gray scale, dye depth and color fastness.

Therefore, the polyamide island-sea fiber monofilament produced by the present invention is finer and has a soft and delicate touch. It has a significantly reduced bending stiffness, a soft luster, a large specific fiber surface area, and a high density structure. The polyamide island-sea fiber monofilament produced by the present invention is suitable for use in fields such as imitation wool, imitation silk, imitation leather, imitation peach skin, imitation suede, high-density waterproof cloth, high-performance washable clothing, high-performance adsorption and filtration materials, highly oil-absorbent materials, highly water-absorbent materials, heat insulating materials, medical materials, automotive equipment materials, safety shoes, cases, handbags, sofas, etc.

Finally, it should be noted that the above embodiments are only used to describe the technical solutions of the present invention, but do not limit them. Although the present invention has been described in detail using the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can be further modified, or some or all of the technical features can be replaced equally. These modifications or replacements do not cause the spirit of the corresponding technical solutions to depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (14)

A polyamide islands-in-the-sea fiber,
the raw material of the island component is a polyamide resin selected from one of polyamide 56, polyamide 510, polyamide 511, polyamide 512, polyamide 513, polyamide 514, polyamide 515 and polyamide 516, and the raw material of the sea component is one of polyethylene, low-density polyethylene, polystyrene, water-soluble polyester, polyester and polyurethane;
The polyamide resin has a relative viscosity of 2.4 to 3.0,
The polyamide sea-island fiber has a fineness of 10 to 300 dtex,
The polyamide islands-in-the-sea fiber has an initial elastic modulus of 20 to 50 cN/dtex. The polyamide islands-in-the-sea fiber according to claim 1,
the polyamide resin is selected from the group consisting of super bright polyamide resin, semi-dull polyamide resin, full-dull polyamide resin and a mixture thereof; and/or the polyamide resin has a relative viscosity of 2.5 to 2.9; and/or the mass ratio of the island part to the sea part of the sea-island fiber is 20-80:80-20. The polyamide island-sea fiber according to claim 1 or 2,
The polyamide islands-in-sea fiber is a fixed island-type islands-in-sea fiber or a non-fixed island-type islands-in-sea fiber; and/or the number of islands in the fixed island-type islands-in-sea fiber is 16 to 500. The polyamide sea-island fiber according to any one of claims 1 to 3,
the polyamide island-sea fiber has a fineness of 20-200 dtex; and/or a breaking strength of 2.0-5.0 cN/dtex; and/or a breaking elongation of 30-80%; and/or an initial elastic modulus of 23-45 cN/dtex; and/or a monofilament fineness of 0.001-0.2 dtex after splitting; and/or a dyeing uniformity (gray scale) of grade 3.5 or higher. The polyamide island-sea fiber according to any one of claims 1 to 4,
the polyamide island-sea fiber has a fineness of 30 to 100 dtex; and/or a breaking strength of 2.5 to 4.5 cN/dtex; and/or a breaking elongation of 40 to 70%; and/or an initial elastic modulus of 28 to 38 cN/dtex; and/or a monofilament fineness of 0.005 to 0.1 dtex after splitting; and/or a dyeing uniformity (gray scale) of grade 4.5 or higher. The method for producing the fixed island type sea-island fiber according to claim 3, comprising the steps of:
1) heating and melting the island component resin and the sea component resin, respectively, to obtain two melts; conveying the two melts through pipes to a spin beam; accurately metering each melt with a metering pump and injecting it into an islands-in-sea composite spin pack in the spin beam; distributing the two melts through a distribution pipe of the spin pack and converging and extruding at the entrance of a spinneret orifice; the island component has a moisture content of less than 1500 ppm, and the sea component has a moisture content of less than 300 ppm; and 2) cooling, spin finishing, drawing, heat setting, and winding the as-formed fiber extruded in step 1) to obtain the fixed islands-in-sea fiber.
Including,
In step 1),
The heating is performed in a screw extruder, the screw extruder including five zones for heating;
For the island component screw, the temperature of the first zone is 200-260°C, the temperature of the second zone is 230-280°C, the temperature of the third zone is 240-290°C, the temperature of the fourth zone is 260-300°C, and the temperature of the fifth zone is 270-310°C;
The process according to claim 1, wherein for the screw for the sea part, the temperature of the first zone is 120-220°C, the temperature of the second zone is 140-240°C, the temperature of the third zone is 160-260°C, the temperature of the fourth zone is 180-280°C, and the temperature of the fifth zone is 160-290°C. 7. The method of claim 6,
In step 1),
the temperature of the spin beam is 200-300°C; and/or the spin pack pressure of the island component is 10.0-15.0 MPa and the spin pack pressure of the sea component is 8.0-15.0 MPa; and the spin pack pressure difference between the sea component and the island component is controlled to be less than 4.0 MPa. 8. The method according to claim 6 or 7,
In step 2),
and/or the cooling is done by quench air or cross air blow, the air speed is 0.2-1.2 m/s, the air temperature of the quench air is 15-30° C., and/or the oil pick-up is 0.2-1.0 wt.%, and/or the drawing process is where the spin-finished as-formed yarn is directed through feed rollers to hot draw rollers for drawing, the draw ratio is 2.0-5.0; and/or the heat setting temperature is 150-220° C.; and/or the take-up speed is 1000-6000 m/min. 9. The method of claim 8,
the air velocity is 0.2 to 1.0 m/s;
The method according to claim 1, wherein the quench air temperature is 20-27°C, and/or the oil pick-up is 0.3-0.8 wt%, and/or the draw ratio is 2.5-3.0; and/or the heat setting temperature is 160-200°C; and/or the winding speed is 2000-5000 m/min. The method for producing the non-fixed island type sea-island fiber according to claim 3, comprising the steps of:
a) homogeneously mixing the island components and the sea component in a certain ratio, then heating and melting the mixture; conveying the resulting blended melt through a pipe to a spin beam; precisely metering the blended melt by a metering pump and injecting it into a one-component spin pack in the spin beam; extruding the blended melt through a spinneret orifice; wherein the island components have a moisture content of less than 1500 ppm; and the sea component has a moisture content of less than 300 ppm;
b) cooling the extruded as-formed fiber, spin finishing, drawing, heat setting and winding to obtain the non-fixed island-in-the-sea fiber;
Including,
In step a),
10. The method of claim 9, wherein the heating is performed in a screw extruder, the screw extruder comprising five zones for heating; the temperature of the first zone is 180-240°C; the temperature of the second zone is 200-260°C; the temperature of the third zone is 220-270°C; the temperature of the fourth zone is 240-280°C; and the temperature of the fifth zone is 200-300°C. 11. The method of claim 10,
In step a),
The method of claim 1, wherein the temperature of the spin beam is 200-300° C.; and the spin pack pressure is 10.0-25.0 MPa. 12. The method according to claim 10 or 11,
In step b),
The method of claim 1, wherein the cooling is done by quench air or cross air blow; the air speed is 0.2-1.2 m/s, and the air temperature of the quench air is 15-30° C.; and/or the oil pick-up is 0.2-1.0 wt. %, and/or the drawing process is where the spin-finished as-formed yarn is directed through feed rollers to hot draw rollers for drawing, and the draw ratio is 2.0-5.0; and/or the heat setting temperature is 150-220° C.; and/or the take-up speed is 1000-6000 m/min. 13. The method of claim 12,
The air velocity is 0.4 to 1.0 m/s,
and/or the quench air temperature is 23-27°C; and/or the oil pick-up is 0.3-0.8 wt%; and/or the draw ratio is 2.5-3.0; and/or the heat setting temperature is 160-200°C; and/or the take-up speed is 2000-5000 m/min. The use of the polyamide sea-island fiber according to any one of claims 1 to 5 in the manufacture of imitation wool, imitation silk, imitation leather, imitation peach skin, imitation suede, high-density waterproof fabric, high-performance washable clothing, high-performance adsorption and filtration material, highly oil-absorbent material, highly water-absorbent material, heat insulation material, medical material, automotive accessory material, safety shoes, cases, handbags or sofas.