A polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles and its preparation

Abstract

The present invention relates to a polyurethane superfine fiber base fabric containing crab stick-shaped superfine fiber bundles and its preparation. The polyurethane superfine fiber base fabric containing crab stick-shaped superfine fiber bundles includes a base layer at the lower layer and a velvet layer at the upper layer. The superfine fibers penetrate through the base layer and the velvet layer of the superfine fiber base fabric in units of superfine fiber bundles formed after the sea-island fibers are split. Waterborne polyurethane resin is filled in the gaps between the superfine fibers or on the surfaces of the superfine fibers in the base layer. The preparation method is as follows: (1) The sea-island fibers are made into a non-woven fabric through carding, web laying, and needling; (2) The non-woven fabric is impregnated with a waterborne polyurethane emulsion, and a waterborne polyurethane sea-island fiber base fabric is obtained by adopting a two-time impregnation and curing process; (3) The waterborne polyurethane sea-island fiber base fabric is split and fluffed to obtain the polyurethane superfine fiber base fabric containing crab stick-shaped superfine fiber bundles. The polyurethane superfine fiber base fabric containing crab stick-shaped superfine fiber bundles prepared by the present invention has abrasion resistance comparable to that of the superfine fiber base fabric made of solvent-based polyurethane.

Description

Technical Field

[0001] The present invention belongs to the technical field of ultra-fine fiber synthetic leather, and relates to a polyurethane ultra-fine fiber base fabric containing crab stick-shaped ultra-fine fiber bundles and its preparation. Background Art

[0002] Ultra-fine fiber base fabrics composed of ultra-fine fibers and elastic polymer compounds such as polyurethane are widely used as artificial leathers in daily life. The flocked products obtained by sueding are widely used as substitutes for suede napped leather. Most of the existing ultra-fine fibers are made by dissolving the sea component of the sea-island structured fixed-island fibers with a solvent to obtain the island component ultra-fine fibers.

[0003] Polyurethane resins are generally divided into solvent-based polyurethane resins and water-based polyurethane resins. Solvent-based polyurethanes use organic solvents such as DMF as the dispersion medium of the polyurethane resin during the preparation process, and the DMF solvent in the polyurethane resin is replaced by an aqueous DMF solution during the coagulation stage after impregnation. Since the solvent-based polyurethane resin is insoluble in water and solidifies, water molecules are dispersed in the polyurethane resin and removed by drying. Water-based polyurethane resins use water as the dispersion medium, and during the curing stage after impregnation, the polyurethane resin loses the dispersion medium and solidifies by removing the water. During this period, the formation of micro-crosslinking also causes the solubility of the polyurethane resin in water to decrease and solidify. It can be seen that when the solvent-based polyurethane solidifies, the inside is still filled with the medium DMF, and the resin film presents a continuous state, and after the DMF is removed, an internal pore structure is given; when the water-based polyurethane solidifies, the emulsion particles accumulate as the water volatilizes, resulting in poor continuity of the resin film in its structure, and it is easy to form a piled state unevenly adhered to the local surface of the fiber. When observed by scanning electron microscopy, it will be found that the fiber surface is usually not wrapped by polyurethane, and some areas are exposed outside. The inventor found that this incomplete wrapping is the reason for poor wear resistance and serious fiber hair loss.

[0004] Therefore, it is of great significance to study a water-based polyurethane ultra-fine fiber base fabric with good wear resistance and its preparation method. Summary of the Invention

[0005] The purpose of the present invention is to solve the above problems existing in the prior art, and provide a polyurethane ultra-fine fiber base fabric containing crab stick-shaped ultra-fine fiber bundles and its preparation.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles, comprising a base layer at the lower layer and a plush layer at the upper layer. The ultrafine fibers penetrate through the base layer and the plush layer of the superfine fiber base fabric in units of ultrafine fiber bundles formed after splitting sea-island fibers. Waterborne polyurethane resin is filled in the gaps between the ultrafine fibers or on the surface of the ultrafine fibers in the base layer, and the plush layer basically does not contain waterborne polyurethane resin;

[0008] The proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles (referring to the quantity proportion) ≥ 50%;

[0009] The crab stick-shaped ultrafine fiber bundles are in a trumpet shape. The part of the crab stick-shaped ultrafine fiber bundles in the plush layer is not wrapped with waterborne polyurethane resin and is in a dispersed fluff state, while the part of the crab stick-shaped ultrafine fiber bundles in the base layer is wrapped with waterborne polyurethane and gathered into a bundle.

[0010] "The plush layer basically does not contain waterborne polyurethane resin" is a reiteration of the state of the plush layer in the prior art for preparing plush superfine leather, rather than a specific state of the plush layer developed in this application. Usually, the plush layer basically does not contain waterborne polyurethane resin and is composed of ultrafine fibers in a loose state. Therefore, compared with the surface of leather without sueding treatment, it has good touch, color and writing effect, and is generally obtained through the sueding process. After treatment, a plush layer that basically does not contain waterborne polyurethane resin is formed. Those skilled in the art can understand that the meaning of "basically does not contain" in the plush layer basically does not contain waterborne polyurethane resin is an objective description of the plush layer in the prior art that basically does not contain waterborne polyurethane as a plush characteristic, rather than a further limitation on the composition of the plush layer in the prior art.

[0011] As a preferred technical solution:

[0012] For the polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles as described above, the part of the crab stick-shaped ultrafine fiber bundles in the base layer is wrapped with waterborne polyurethane and gathered into a bundle, which means observing the cross-sectional morphology of the base layer under an electron scanning electron microscope, and at least 3 / 4 of the edge perimeter of the ultrafine fiber bundle is covered by waterborne polyurethane, so that the fiber bundle is in a gathered state without spreading.

[0013] For the polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles as described above, the abrasion loss of the polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles tested according to the GB / T 21196.2-2007 standard for 35000 times is 15-25 mg.

[0014] The present invention also provides a preparation method of the polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles as described above, comprising the following steps:

[0015] (1) The sea-island fibers are made into non-woven fabric through carding, web laying, and needling. The needling process is the key process for the present invention to achieve the above technical effects. The preparation of the sea-island fiber raw materials, fiber carding, and web laying processes in the early stage are applicable to conventional process means and can be selected according to specific requirements and expectations. The suede-like touch and appearance obtained from the ultrafine fibers are just like those of traditional suede. When using sea-island fibers to prepare non-woven fabric, the fibers obtained by melt spinning usually need to be heat-stretched and crimped, and then generally cut into short fibers of 51 mm. These processes are applicable to conventional processes and can be adjusted by those skilled in the art according to needs. In the non-woven fabric of the present invention, the above sea-island fibers can be intertwined through carding, web laying, and needling;

[0016] (2) The non-woven fabric obtained in step (1) is impregnated with an aqueous polyurethane emulsion, and an aqueous polyurethane sea-island fiber base fabric is obtained by using a two-time impregnation and curing process;

[0017] (3) The aqueous polyurethane sea-island fiber base fabric obtained in step (2) is opened and fluffed to obtain the polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles;

[0018] In step (1), a single-hook needle type is used for needling, and the needling density is 3000 - 4500 needles / cm 2 ;

[0019] In step (2), the product of the concentration of the impregnating material (prepared from the aqueous polyurethane emulsion) and the calculated value of the liquid carrying rate of the impregnating material is defined as the resin sizing amount. The concentration of the impregnating material during the first impregnation is 13 - 22 wt%, and the liquid carrying rate is controlled so that the resin sizing amount W1 is 17 - 25 wt%; the concentration of the impregnating material during the second impregnation is 5 - 12 wt%, and the liquid carrying rate is controlled so that the resin sizing amount W2 is 6.5 - 14 wt%.

[0020] The curing after each impregnation is divided into two stages. The first stage is the low-temperature zone of 80 - 95 °C, and the water evaporation rate ≥ 70%. The second stage is the high-temperature zone of 130 - 140 °C, and the water evaporation rate ≥ 99.8%.

[0021] The needling process is essentially to drive the fibers originally parallel to the web direction to move perpendicular to the web direction under the up and down movement of the external needle, so that the originally parallel fibers are intertwined and interpenetrated vertically. After needling, the density of the non-woven fabric becomes compact, and the entanglement between the fibers makes the non-woven fabric have a certain fastness. As a means parameter for achieving the purpose of the present invention, the setting of the needling process not only obtains the entanglement of the fibers to make the non-woven fabric compact, but more importantly, adjusts more fibers to tend to be in an upright state, including the adjustment of the needling density and the selection of the hook needle type.

[0022] Needling is carried out using a single crochet needle type (model: R100). The advantage of a single crochet is that the fibers passing through can be more inclined to stand upright at the tail end, and such a fiber morphology is more conducive to forming a basically complete covering of crab stick-shaped ultrafine fiber bundles;

[0023] A sufficient needling density ensures that the fibers originally parallel to the web direction can form an arrangement structure that penetrates up and down. Driven by the needle, the fibers can be fully entangled and penetrate the web like nails. After needling, the density of the non-woven fabric becomes compact, and the entanglement between the fibers makes the non-woven fabric have a certain firmness. When the needling density is less than 3000 needles / cm 2 At this time, due to the too small needling density, it is not enough to change the state of fiber distribution parallel to the web to form sufficient fiber penetration and entanglement, which is not conducive to uniform wrapping. When the needling density is greater than 3000 needles / cm 2 At this time, a sufficient number of needling times enables almost all the fibers to penetrate the web. When the needling density is too large (>4500 needles / cm 2 ), on the contrary, the longitudinally penetrating fibers will be pressed in again, and the distribution of the fibers in the longitudinal direction tends to be flattened, and the density increases. Although there are more fiber entanglements, it is not conducive to obtaining more upright fibers, and at the same time, fiber breakage is likely to occur; because when the waterborne polyurethane impregnates and cures the fibers, it will move along with the curing process. Upright fibers are conducive to the movement and spreading of the waterborne polyurethane in the direction of a single sea-island fiber, rather than accumulating in the gaps between multiple fibers.

[0024] The present invention adopts a two-time impregnation and curing process, that is, impregnation and curing, and then re-impregnation and curing. The two-time curing is the key to obtaining ultrafine fiber bundles.

[0025] As described in the background technology, when the waterborne polyurethane cures, as the water is continuously extracted, the waterborne polyurethane particles tend to accumulate on the fiber surface, making the waterborne polyurethane present a discontinuous distribution as a whole. Usually, when using a single impregnation, a large resin filling needs to be achieved, and the resin is extremely likely to accumulate locally during movement. Therefore, the local wrapping of the waterborne polyurethane around the fiber surface obtained is usually discontinuous, as Figure 2 shown.

[0026] The present invention adopts two-time impregnation and curing. The filling of the first impregnation and curing is insufficient, and then the second impregnation and curing is carried out to fill the missing part of the coating. The control requirements for the two-time impregnation process are extremely high, because once the impregnation is excessive, it will cause the feel of the superfine fiber base fabric to be stiff. That is to say, we expect to achieve sufficient polyurethane wrapping to obtain high wear resistance and the surface fibers are not easy to shed hair, but we do not expect the polyurethane to overly fill the gaps, making the feel of the superfine fiber base fabric hard. We expect a more sufficient resin coating degree in the direction close to the base layer and a smaller resin coating degree in the direction close to the pile surface layer, so as to make the surface feel softer.

[0027] For the first impregnation, the concentration range of the impregnating material is controlled to be 13 - 22 wt%, and the control of the liquid carrying rate of the impregnating material is based on the premise that the resin sizing amount is 17 - 25 wt%. A lower concentration of the impregnation amount means that the continuous phase filled in the gaps of the non-woven fabric consists of less polyurethane resin (17 - 25 wt%) and more water (75 - 83 wt%); in the subsequent drying and curing process, these waters vaporize and diffuse outwards, while the polyurethane resin shrinks inward to fill the space left by the vaporization of the moisture. The large proportion of solvent water is conducive to the extraction of moisture during the curing stage to form sufficient gaps. The control of this step determines the softness of the entire base fabric; after the first impregnation and curing are completed, the space near the base layer is easily filled by the shrinkage of polyurethane, while the space far from the base layer is less filled. Especially, the entanglement of the surface fibers is less, and they are basically upright in the direction of the fiber web. Polyurethane adheres more independently to the surface of the fibers. Since the resin content of the polyurethane in the first impregnation is less, the total liquid carrying rate is not high, and relatively the curing time is short, which will not cause the polyurethane between two fibers to converge and accumulate when moving as in the prior art, but only flow along the direction of the fibers and finally slightly accumulate on the matrix layer, which is what we expect. This can not only make the implantation of the fibers in the base fabric more firm, but also does not affect the hand feeling. Due to the low resin content of the polyurethane, it is impossible to achieve a relatively complete coating of the fiber bundle during the curing and shrinking process.

[0028] For the second impregnation, the concentration of the impregnating material is controlled to be 5 - 12 wt%, and the liquid carrying rate is controlled so that the resin sizing amount W2 is 6.5 - 14 wt%. During the second impregnation, the impregnation amount is distributed in the gaps formed by the fibers and the cured polyurethane. A lower concentration of polyurethane is selected, which means that the polyurethane slurry can more fully fill the internal gaps, which is crucial for making up for the imperfect coating of polyurethane during the first impregnation. In the second curing stage, the uncured polyurethane tends to undergo micro-crosslinking curing around the cured polyurethane, so that the fibers are more completely coated, and the overall distribution still shows a trend of gradually decreasing content from the base layer to the fluff layer.

[0029] In step (1), the sea-island weight ratio in the sea-island fiber is 20:80 - 50:50;

[0030] After the waterborne polyurethane sea-island fiber base fabric obtained in step (2) is opened, the resin content therein ≤ 40 wt%, and the calculation formula is as follows:

[0031] PU% = (100 * W1 + (100 + 100 * W1) * W2) / (100 * M + 100 * W1 + (100 + 100 * W1) * W2);

[0032] PU%: Resin content in the fibrillated base fabric;

[0033] W1: Sizing amount of resin in the first impregnation;

[0034] W2: Sizing amount of resin in the second impregnation;

[0035] M: Island content in the sea-island fiber;

[0036] During the entire impregnation stage, the resin content of the impregnation should not be too high to prevent the base fabric from becoming stiff due to excessive resin filling. During a single impregnation process, the concentration range of the impregnating material should be controlled at a relatively low level. If the resin content is too low, the resin will wrap too little around the fiber bundle, and it will be impossible to obtain a sufficient proportion of crabstick-shaped ultrafine fiber bundles. After fibrillating, if the resin content in the base fabric exceeds 40 wt%, the resin will wrap too tightly around the fiber bundle, failing to meet the requirement of a plush feel, and the finished product will feel too hard.

[0037] The curing of the impregnation is divided into two stages: a low-temperature zone of 80 - 95 °C with a water evaporation rate ≥ 70%; a high-temperature zone of 130 - 140 °C with a water evaporation rate ≥ 99.8%. The low-temperature zone is set first to control the water evaporation rate. As the water slowly evaporates at low temperature, the resin can cure quickly, achieving uniform coating of the resin on the surface of the fiber. Then, high temperature is applied to completely evaporate the water and completely crosslink and cure the resin. If direct high-temperature curing is used, the instantaneous water evaporation rate is too fast, which will drive the movement of the resin. Due to the random arrangement of the fibers, the distribution of the resin will be more discontinuous, which is not conducive to the wrapping of the resin around the fiber.

[0038] As a preferred technical solution:

[0039] In the method as described above, the sea-island fiber in step (1) is a sea-island fiber with conventional components. Appropriate sea components and island components can be selected according to requirements. The sea component is a conventional COPET or LDPE resin, and the island component is conventionally PA6, PET, etc.

[0040] In the method as described above, in order to increase the density of the non-woven fabric and prevent the non-woven fabric from deforming during processing, after step (1) of needling, a heat shrinkage setting process is also carried out.

[0041] In the method as described above, the heat shrinkage setting is carried out in a manner of gradient heating, and the temperature of the heat shrinkage setting is 90 - 140 °C.

[0042] For the method described above, in step (3), the fiber opening process is a conventional fiber opening process. It can be based on "Synthetic Leather Technology" written by Qu Jianbo, Chemical Industry Press, or can be carried out with reference to the following process: For the resin with a sea component of COPET, an alkali solution is used as the fiber opening solvent, and the alkali solution concentration can be set at 2-8%, and the temperature is 90-95°C; for the resin with a sea component of LDPE, toluene is used as the fiber opening solvent, and the toluene circulation rate can be set at 10-15m 3 / h, the roll pressure is 0.1-0.5 MPa, and the toluene temperature is 80-110°C.

[0043] For the method described above, in step (3), napping is carried out by using conventional sandpaper to polish to form a nap layer. This process is to disperse the fibers after the nap layer is completely fiber-opened, grind the surface flat, and present the texture of suede. This process is applicable to conventional processes, and those skilled in the art can make corresponding adjustments according to needs.

[0044] Beneficial effects:

[0045] The characteristics of the superfine fiber base fabric of the present invention are that the superfine fiber base fabric contains a large number of crab stick-shaped ultrafine fiber bundles. The crab stick-shaped ultrafine fiber bundles form scattered fluff in the nap layer part, while in the base layer part, they are wrapped by polyurethane basically intact and form bundles. Compared with traditional ultrafine fiber bundles, the crab stick-shaped ultrafine fiber bundles are more firmly bound in the waterborne polyurethane resin, with less fluff shedding, and the abrasion resistance can be comparable to that of the superfine fiber base fabric made of solvent-based polyurethane. Description of the drawings

[0046] Figure 1 It is the coating state of the ultrafine fibers by the waterborne polyurethane presented by the cross-section of the polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles prepared in Example 1;

[0047] Figure 2 It is the coating state of the waterborne polyurethane resin on the ultrafine fibers presented by the cross-section of the waterborne polyurethane superfine fiber base fabric of Comparative Example 5. Detailed implementation manners

[0048] The following further elaborates the present invention in combination with specific implementation manners. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0049] In the present invention, the calculated value obtained by multiplying the concentration of the impregnating material by the liquid carrying rate of the impregnating material is defined as the resin sizing amount;

[0050] The calculation formula for the resin content in the polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles is as follows:

[0051] PU% = (100 * W1 + (100 + 100 * W1) * W2) / (100 * M + 100 * W1 + (100 + 100 * W1) * W2);

[0052] PU%: Resin content in the fibrillated base fabric;

[0053] W1: Sizing amount of resin in the first impregnation;

[0054] W2: Sizing amount of resin in the second impregnation;

[0055] M: Island content in the sea-island fiber;

[0056] In the embodiments of the present invention, heat shrinkage setting is carried out in a gradient heating manner, successively at 90 °C for 1 min, 100 °C for 1 min, 110 °C for 1 min, 120 °C for 1 min, 130 °C for 1 min, and 140 °C for 1 min;

[0057] In the embodiments of the present invention, when the sea component is COPET, an alkali solution (NaOH solution) is used as the fibrillating solvent, the concentration of the alkali solution is 5 wt%, and the temperature is 92 °C; when the sea component is LDPE, toluene is used as the fibrillating solvent, the set toluene circulation amount is 12 m 3 / h, the roll pressure is 0.3 MPa, and the toluene temperature is 95 °C.

[0058] Example 1

[0059] A preparation method of a polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles is as follows:

[0060] (1) Raw material preparation:

[0061] The raw material is sea-island fiber, the fineness of the sea-island fiber is 3.5 dtex, the sea component is COPET, the island component is PA6, and the sea-island weight ratio in the sea-island fiber is 30:70;

[0062] (2) Card and lay the sea-island fiber, and then carry out needling using a single barbed needle type (model: R100), the needling density is 4500 needles / cm 2 , and after needling, carry out heat shrinkage setting to make a non-woven fabric;

[0063] (3) Immerse the non-woven fabric prepared in step (2) in an aqueous polyurethane emulsion, and obtain an aqueous polyurethane sea-island fiber base fabric by using a two-time impregnation and curing process;

[0064] Among them, the concentration of the impregnating material during the first impregnation is 18 wt%, and the liquid carrying rate is controlled so that the resin sizing amount is 25%; the concentration of the impregnating material during the second impregnation is 5 wt%, and the liquid carrying rate is controlled so that the resin sizing amount is 6.5%.

[0065] The curing after each impregnation is divided into two stages. The first stage is the low temperature zone of 85 °C, and the water evaporation rate is 70%. The second stage is the high temperature zone of 140 °C, and the water evaporation rate is 99.8%.

[0066] (4) Open the waterborne polyurethane sea-island fiber base fabric obtained in step (3), and then use sandpaper to repeatedly polish one layer of the opened superfine fiber base fabric to form a velvet surface layer, thus obtaining a polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles.

[0067] The obtained polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles includes a base layer at the lower layer and a velvet surface layer at the upper layer; the ultrafine fibers penetrate through the base layer and the velvet surface layer of the superfine fiber base fabric in units of the ultrafine fiber bundles formed after the opening of the sea-island fibers; the waterborne polyurethane resin is filled in the gaps between the ultrafine fibers of the base layer; the resin content in the polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles is 32.1 wt%.

[0068] The proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles (referring to the quantity proportion) is 65%. The crab stick-shaped ultrafine fiber bundles are in a trumpet shape. The part of the crab stick-shaped ultrafine fiber bundles in the velvet surface layer is not wrapped with the waterborne polyurethane resin and is in a dispersed fluff state, while the part of the crab stick-shaped ultrafine fiber bundles in the base layer is wrapped with the waterborne polyurethane and gathered into a bundle; as Figure 1 shown, the circled part in the figure is the crab stick-shaped ultrafine fiber bundles. It can be seen that the ultrafine fiber bundles are well coated with the waterborne polyurethane and gathered into a bundle; the velvet surface layer basically does not contain the waterborne polyurethane resin.

[0069] The polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles, when tested according to the standard of GB / T 21196.2-2007, after 35000 tests, the abrasion loss is 15 mg.

[0070] Comparative Example 1

[0071] A preparation method of a waterborne polyurethane superfine fiber base fabric, the specific steps are basically the same as those in Example 1, the difference is only that in step (2), a three-hook needle type is used for needling (model: R111).

[0072] The resin content in the obtained polyurethane superfine fiber base fabric is 32.1 wt%; the proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles (referring to the quantity proportion) is 45%.

[0073] The polyurethane superfine fiber base fabric is tested according to the standard of GB / T 21196.2-2007, and the abrasion loss after 35000 tests is 35 mg.

[0074] Comparing Comparative Example 1 with Example 1, it can be found that the proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles in Example 1 is significantly higher than that in Comparative Example 1, while the abrasion amount after 35,000 tests in Example 1 is significantly lower than that in Comparative Example 1; this is because after modifying the single-hook needle to a multi-hook needle such as a three-hook needle, the longitudinal distribution of the fibers will tend to be flattened, which is not conducive to the upright of the fibers, and thus not conducive to obtaining the coated state of the crab stick-shaped ultrafine fiber bundles.

[0075] Comparative Example 2

[0076] A preparation method of a waterborne polyurethane ultrafine fiber base fabric, the specific steps are basically the same as those in Example 1, the difference is only that the needling density in step (2) is 2000 needles / cm 2 ;

[0077] The resin content in the prepared polyurethane ultrafine fiber base fabric is 32.1 wt%; the proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles (referring to the quantity proportion) is 35%;

[0078] The polyurethane ultrafine fiber base fabric is tested according to the GB / T 21196.2-2007 standard, and the abrasion amount after 35,000 tests is 43 mg.

[0079] Comparing Comparative Example 2 with Example 1, it can be found that the proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles in Example 1 is significantly higher than that in Comparative Example 2, while the abrasion amount after 35,000 tests in Example 1 is significantly lower than that in Comparative Example 2; this is because the needling density is too small to change the state of the fibers parallel to the fiber web distribution to form sufficient fiber interpenetration and entanglement, which is not conducive to uniform wrapping.

[0080] Comparative Example 3

[0081] A preparation method of a waterborne polyurethane ultrafine fiber base fabric, the specific steps are basically the same as those in Example 1, the difference is only that the needling density in step (2) is 5000 needles / cm 2 ;

[0082] The resin content in the prepared polyurethane ultrafine fiber base fabric is 32.1 wt%; the proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles (referring to the quantity proportion) is 50%;

[0083] The polyurethane ultrafine fiber base fabric is tested according to the GB / T 21196.2-2007 standard, and the abrasion amount after 35,000 tests is 31 mg.

[0084] Comparing Comparative Example 3 with Example 1, it can be found that the proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles in Example 1 is significantly higher than that in Comparative Example 3, while the abrasion amount after 35,000 tests in Example 1 is significantly lower than that in Comparative Example 3. This is because when the needling density is too high, the fibers that are longitudinally interspersed will be pressed in again, and the distribution of the fibers in the longitudinal direction tends to be flattened, and the density increases. Although there are more fiber entanglements, it is not conducive to obtaining more upright fibers, and at the same time, fiber breakage is likely to occur. Because when the waterborne polyurethane impregnates and cures the fibers, it will move with the curing process, and the upright fibers are conducive to the movement and spreading of the waterborne polyurethane in the direction of single sea-island fibers, rather than accumulating in the gaps between multiple fibers.

[0085] Comparative Example 4

[0086] A preparation method of a waterborne polyurethane superfine fiber base fabric, the specific steps are basically the same as those in Example 1, the difference is only that in the first impregnation in step (3), the liquid pick-up rate of the impregnating material is controlled so that the resin sizing amount is 30%;

[0087] The resin content in the prepared polyurethane superfine fiber base fabric is 35.5 wt%; the proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles (referring to the quantity proportion) is 52%;

[0088] The polyurethane superfine fiber base fabric is tested according to the GB / T 21196.2-2007 standard, and the abrasion amount after 35,000 tests is 28 mg.

[0089] Comparing Comparative Example 4 with Example 1, it can be found that the proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles in Example 1 is significantly higher than that in Comparative Example 4, while the abrasion amount after 35,000 tests in Example 1 is significantly lower than that in Comparative Example 4. This is because when the resin amount is too high during the first impregnation, the polyurethane between two fibers accumulates at the intersection during movement, which is likely to cause local agglomeration and detachment from the fiber surface.

[0090] Comparative Example 5

[0091] A preparation method of a waterborne polyurethane superfine fiber base fabric, the specific steps are basically the same as those in Example 1, the difference is only that in step (3), a one-time impregnation and curing process is adopted, the concentration of the impregnating material during impregnation is 30 wt%, and the liquid pick-up rate is controlled so that the resin sizing amount is 33.1%;

[0092] The resin content in the prepared polyurethane superfine fiber base fabric is 32.1 wt%; the proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles (referring to the quantity proportion) is 32%; as Figure 2 shown, the circled part in the figure is the crab stick-shaped ultrafine fiber bundle. It can be seen that the waterborne polyurethane shows local agglomeration, and the fiber bundle is not well coated and presents a loose state, making it difficult to clearly distinguish the ultrafine fiber bundles obtained from different sea-island fibers;

[0093] The polyurethane ultra-fine fiber base fabric was tested according to the standard of GB / T 21196.2-2007, and the abrasion loss after 35,000 tests was 45 mg.

[0094] Comparing Comparative Example 5 with Example 1, it can be found that the proportion of crab stick-shaped ultra-fine fiber bundles in the ultra-fine fiber bundles in Example 1 is significantly higher than that in Comparative Example 5, while the abrasion loss after 35,000 tests in Example 1 is significantly lower than that in Comparative Example 5. This is because when using single impregnation, a large amount of resin filling needs to be achieved at one time, and the resin is extremely prone to local accumulation during movement. Therefore, the local coating of the waterborne polyurethane around the fiber surface obtained is usually discontinuous.

[0095] Example 2

[0096] A preparation method of a polyurethane ultra-fine fiber base fabric containing crab stick-shaped ultra-fine fiber bundles is as follows:

[0097] (1) Raw material preparation:

[0098] The raw material is sea-island fiber. The fineness of the sea-island fiber is 3.5 dtex. The sea component is COPET, and the island component is PA6. The weight ratio of sea to island in the sea-island fiber is 30:70;

[0099] (2) Card and lay the sea-island fiber, and then use a single barbed needle type for needling (model: R100). The needling density is 4,500 needles / cm 2 , and after needling, perform heat shrinkage setting to make a non-woven fabric;

[0100] (3) Immerse the non-woven fabric prepared in step (2) in a waterborne polyurethane emulsion, and use a two-time impregnation and curing process to obtain a waterborne polyurethane sea-island fiber base fabric;

[0101] Among them, the concentration of the impregnating material during the first impregnation is 22 wt%, and the liquor pickup rate is controlled so that the resin sizing amount is 25%; the concentration of the impregnating material during the second impregnation is 5 wt%, and the liquor pickup rate is controlled so that the resin sizing amount is 6.5%;

[0102] The curing after each impregnation is divided into two stages. The first stage is the low temperature zone of 85 °C, and the water evaporation rate is 70%. The second stage is the high temperature zone of 140 °C, and the water evaporation rate is 99.8%;

[0103] (4) Open the fiber of the waterborne polyurethane sea-island fiber base fabric obtained in step (3), and then use sandpaper to repeatedly polish one layer of the opened ultra-fine fiber base fabric to form a velvet surface layer, and obtain a polyurethane ultra-fine fiber base fabric containing crab stick-shaped ultra-fine fiber bundles.

[0104] The polyurethane superfine fiber base fabric containing crab stick-shaped superfine fiber bundles includes a base layer at the lower layer and a velvet layer at the upper layer; the superfine fibers penetrate through the base layer and the velvet layer of the superfine fiber base fabric in units of superfine fiber bundles formed after splitting sea-island fibers; waterborne polyurethane resin is filled in the gaps between the superfine fibers in the base layer; the velvet layer basically does not contain waterborne polyurethane resin;

[0105] In the polyurethane superfine fiber base fabric containing crab stick-shaped superfine fiber bundles, the resin content is 32.1 wt%; the proportion of crab stick-shaped superfine fiber bundles in the superfine fiber bundles (referring to the quantity proportion) is 60%, the crab stick-shaped superfine fiber bundles are trumpet-shaped, the part of the crab stick-shaped superfine fiber bundles in the velvet layer is not wrapped with waterborne polyurethane resin and is dispersed into fluff, and the part of the crab stick-shaped superfine fiber bundles in the base layer is wrapped with waterborne polyurethane and gathered into a bundle;

[0106] The polyurethane superfine fiber base fabric containing crab stick-shaped superfine fiber bundles, when tested according to the standard of GB / T 21196.2-2007, is tested 35000 times, and the abrasion loss is 18 mg.

[0107] Example 3

[0108] A preparation method of a polyurethane superfine fiber base fabric containing crab stick-shaped superfine fiber bundles is as follows:

[0109] (1) Raw material preparation:

[0110] The raw material is sea-island fiber, the fineness of the sea-island fiber is 5.5 dtex, the sea component is COPET, the island component is PA6, and the sea-island weight ratio in the sea-island fiber is 20:80;

[0111] (2) Card and lay the sea-island fibers, and then use a single barbed needle type for needling (model: R100), the needling density is 3000 needles / cm 2 , and after needling, perform heat shrinkage setting to make a non-woven fabric;

[0112] (3) Immerse the non-woven fabric obtained in step (2) in a waterborne polyurethane emulsion, and use a two-time impregnation and curing process to obtain a waterborne polyurethane sea-island fiber base fabric;

[0113] Among them, when impregnating for the first time, the concentration of the impregnating material is 15 wt%, and the pick-up rate is controlled so that the resin sizing amount is 18%; when impregnating for the second time, the concentration of the impregnating material is 12 wt%, and the pick-up rate is controlled so that the resin sizing amount is 14%;

[0114] The curing after each impregnation is divided into two stages. The first stage is the low temperature zone of 85 °C, and the water evaporation rate is 75%. The second stage is the high temperature zone of 140 °C, and the water evaporation rate is 99.9%;

[0115] (4) Open the fibers of the waterborne polyurethane sea-island fiber base fabric obtained in step (3), and then use sandpaper to repeatedly polish one layer of the opened microfiber base fabric for multiple times to form a velvet layer, thereby obtaining a polyurethane microfiber base fabric containing crab stick-shaped ultrafine fiber bundles.

[0116] The polyurethane microfiber base fabric containing crab stick-shaped ultrafine fiber bundles includes a base layer at the lower layer and a velvet layer at the upper layer; the ultrafine fibers penetrate through the base layer and the velvet layer of the microfiber base fabric in units of ultrafine fiber bundles formed after opening the sea-island fibers; the waterborne polyurethane resin is filled in the gaps between the ultrafine fibers in the base layer; the velvet layer basically does not contain waterborne polyurethane resin;

[0117] In the polyurethane microfiber base fabric containing crab stick-shaped ultrafine fiber bundles, the resin content is 30.1 wt%; the proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles (referring to the quantity proportion) is 56%, the crab stick-shaped ultrafine fiber bundles are in a trumpet shape, the part of the crab stick-shaped ultrafine fiber bundles in the velvet layer is not wrapped with waterborne polyurethane resin and is dispersed into fluff, and the part of the crab stick-shaped ultrafine fiber bundles in the base layer is wrapped with waterborne polyurethane and gathered into a bundle;

[0118] The polyurethane microfiber base fabric containing crab stick-shaped ultrafine fiber bundles, when tested according to the standard of GB / T 21196.2-2007, after 35000 tests, the abrasion loss is 20 mg.

[0119] Example 4

[0120] A preparation method of a polyurethane microfiber base fabric containing crab stick-shaped ultrafine fiber bundles, the specific steps are as follows:

[0121] (1) Raw material preparation:

[0122] The raw material is sea-island fiber, the fineness of the sea-island fiber is 2.5 dtex, the sea component is LDPE, the island component is PA6, and the sea-island weight ratio in the sea-island fiber is 50:50;

[0123] (2) Card and lay the sea-island fibers, and then use a single barbed needle type for needling (model: R100), the needling density is 3500 needles / cm 2 , and perform heat shrinkage setting after needling to make a non-woven fabric;

[0124] (3) Immerse the non-woven fabric prepared in step (2) in a waterborne polyurethane emulsion, and use a two-time impregnation and curing process to obtain a waterborne polyurethane sea-island fiber base fabric;

[0125] Among them, when impregnating for the first time, the concentration of the impregnating material is 20 wt%, and the liquor pickup rate is controlled so that the resin sizing amount is 23%; when impregnating for the second time, the concentration of the impregnating material is 7 wt%, and the liquor pickup rate is controlled so that the resin sizing amount is 8.4%;

[0126] The curing after each impregnation is divided into two stages. The first stage is the low-temperature zone at 85°C with a water evaporation rate of 80%, and the second stage is the high-temperature zone at 140°C with a water evaporation rate of 99.9%.

[0127] (4) Open the waterborne polyurethane sea-island fiber base fabric obtained in step (3), and then use sandpaper to repeatedly polish one layer of the opened superfine fiber base fabric to form a velvet layer, thus obtaining a polyurethane superfine fiber base fabric containing crabstick-shaped ultrafine fiber bundles.

[0128] The polyurethane superfine fiber base fabric containing crabstick-shaped ultrafine fiber bundles includes a base layer at the lower layer and a velvet layer at the upper layer; the ultrafine fibers penetrate through the base layer and the velvet layer of the superfine fiber base fabric in units of ultrafine fiber bundles formed after opening the sea-island fibers; the waterborne polyurethane resin is filled in the gaps between the ultrafine fibers in the base layer; the velvet layer basically does not contain waterborne polyurethane resin.

[0129] In the polyurethane superfine fiber base fabric containing crabstick-shaped ultrafine fiber bundles, the resin content is 40 wt%; the proportion of crabstick-shaped ultrafine fiber bundles in the ultrafine fiber bundles (referring to the quantity proportion) is 55%. The crabstick-shaped ultrafine fiber bundles are in a horn shape. The part of the crabstick-shaped ultrafine fiber bundles in the velvet layer is not wrapped with waterborne polyurethane resin and is dispersed into fluff, while the part of the crabstick-shaped ultrafine fiber bundles in the base layer is wrapped with waterborne polyurethane and gathered into a bundle.

[0130] The polyurethane superfine fiber base fabric containing crabstick-shaped ultrafine fiber bundles, when tested according to the standard of GB / T 21196.2-2007 for 35000 times, has a wear loss of 17 mg.

[0131] Example 5

[0132] A preparation method of a polyurethane superfine fiber base fabric containing crabstick-shaped ultrafine fiber bundles, the specific steps are as follows:

[0133] (1) Raw material preparation:

[0134] The raw material is sea-island fiber. The fineness of the sea-island fiber is 4 dtex, the sea component is COPET, the island component is PA6, and the sea-island weight ratio in the sea-island fiber is 40:60.

[0135] (2) Card and lay the sea-island fibers, and then use a single barbed needle type for needling (model: R100), the needling density is 4000 needles / cm 2 , and after needling, perform heat shrinkage setting to make a non-woven fabric.

[0136] (3) Immerse the non-woven fabric prepared in step (2) in a waterborne polyurethane emulsion, and use a two-time impregnation and curing process to obtain a waterborne polyurethane sea-island fiber base fabric.

[0137] Among them, the concentration of the impregnating material during the first impregnation is 13 wt%, and the liquid carrying rate is controlled so that the resin sizing amount is 16.9%; the concentration of the impregnating material during the second impregnation is 10 wt%, and the liquid carrying rate is controlled so that the resin sizing amount is 12%.

[0138] The curing after each impregnation is divided into two stages. The first stage is the low-temperature zone at 85 °C with a water evaporation rate of 75%, and the second stage is the high-temperature zone at 140 °C with a water evaporation rate of 99.9%.

[0139] (4) Open the fibers of the waterborne polyurethane sea-island fiber base fabric obtained in step (3), and then use sandpaper to repeatedly polish one layer of the opened superfine fiber base fabric for many times to form a velvet surface layer, thereby obtaining a polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles.

[0140] The polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles includes a base layer at the lower layer and a velvet surface layer at the upper layer; the ultrafine fibers penetrate through the base layer and the velvet surface layer of the superfine fiber base fabric in units of ultrafine fiber bundles formed after the opening of the sea-island fibers; the waterborne polyurethane resin is filled in the gaps between the ultrafine fibers of the base layer; the velvet surface layer basically does not contain waterborne polyurethane resin.

[0141] In the polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles, the resin content is 34 wt%; the proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles (referring to the quantity proportion) is 50%. The crab stick-shaped ultrafine fiber bundles are in a trumpet shape. The part of the crab stick-shaped ultrafine fiber bundles in the velvet surface layer is not wrapped with waterborne polyurethane resin and is dispersed into fluff, while the part of the crab stick-shaped ultrafine fiber bundles in the base layer is wrapped with waterborne polyurethane and gathered into a bundle.

[0142] The polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles is tested according to the GB / T 21196.2-2007 standard for 35,000 times, and the abrasion loss is 25 mg.

Claims

1. A polyurethane ultra-fine fiber base fabric containing crab stick-shaped ultra-fine fiber bundles, comprising a base layer at the lower layer and a plush layer at the upper layer, characterized in that: The ultrafine fibers penetrate through the base layer and the velvet layer of the superfine fiber base fabric in units of ultrafine fiber bundles formed after the sea-island fibers are split, and the waterborne polyurethane resin is filled in the gaps between the ultrafine fibers or on the surfaces of the ultrafine fibers in the base layer; The proportion of crab stick-shaped ultrafine fiber bundles in the ultrafine fiber bundles is ≥50%; The crab stick-shaped ultrafine fiber bundles are in a trumpet shape. The part of the crab stick-shaped ultrafine fiber bundles in the velvet layer is not wrapped with the waterborne polyurethane resin and is in the form of dispersed fluff, while the part of the crab stick-shaped ultrafine fiber bundles in the base layer is wrapped with the waterborne polyurethane and gathered into a bundle; The part of the crab stick-shaped ultrafine fiber bundles in the base layer is wrapped with the waterborne polyurethane and gathered into a bundle, which means that when observing the cross-sectional morphology of the base layer under an electron scanning electron microscope, at least 3 / 4 of the edge perimeter of the ultrafine fiber bundle is covered by the waterborne polyurethane, so that the fiber bundle is in a gathered state without spreading; The preparation method includes the following steps: (1) The sea-island fibers are made into a non-woven fabric through carding, web laying, and needling; (2) The non-woven fabric obtained in step (1) is impregnated with a waterborne polyurethane emulsion, and a waterborne polyurethane sea-island fiber base fabric is obtained by using a two-time impregnation and curing process; (3) The waterborne polyurethane sea-island fiber base fabric obtained in step (2) is split and fluffed to obtain the polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles; In step (1), single crochet needle type is used for needling, and the needling density is 3000 - 4500 needles / cm 2 ; In step (2), the calculated value of multiplying the concentration of the impregnating material by the liquid pickup rate of the impregnating material on the non-woven fabric is defined as the resin sizing amount. The concentration of the impregnating material during the first impregnation is 13-22 wt%, and the liquid pickup rate is controlled so that the resin sizing amount is 17-25 wt%; the concentration of the impregnating material during the second impregnation is 5-12 wt%, and the liquid pickup rate is controlled so that the resin sizing amount is 6.5-14 wt%; The curing after each impregnation is divided into two stages. The first stage is a low-temperature zone of 80-95 °C, and the water evaporation rate is ≥70%. The second stage is a high-temperature zone of 130-140 °C, and the water evaporation rate is ≥99.8%.

2. The polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles according to claim 1, characterized in that, The abrasion loss of the polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles is 15-25 mg when tested 35,000 times according to the standard of GB / T 21196.2-2007.

3. The preparation method of a polyurethane ultra-fine fiber base fabric containing crab stick-shaped ultra-fine fiber bundles according to any one of claims 1 to 2, characterized in that It includes the following steps: (1) The sea-island fibers are made into a non-woven fabric through carding, web laying, and needling; (2) The non-woven fabric obtained in step (1) is impregnated with a waterborne polyurethane emulsion, and a waterborne polyurethane sea-island fiber base fabric is obtained by using a two-time impregnation and curing process; (3) The waterborne polyurethane sea-island fiber base fabric obtained in step (2) is split and fluffed to obtain the polyurethane superfine fiber base fabric containing crab stick-shaped ultrafine fiber bundles; In step (1), single crochet type needle punching is adopted, and the needle punching density is 3000 - 4500 punches / cm 2 ; In step (2), the calculated value of multiplying the concentration of the impregnating material by the liquid pickup rate of the impregnating material on the non-woven fabric is defined as the resin sizing amount. The concentration of the impregnating material during the first impregnation is 13-22 wt%, and the liquid pickup rate is controlled so that the resin sizing amount is 17-25 wt%; the concentration of the impregnating material during the second impregnation is 5-12 wt%, and the liquid pickup rate is controlled so that the resin sizing amount is 6.5-14 wt%; The curing after each impregnation is divided into two stages. The first stage is a low-temperature zone of 80-95 °C, and the water evaporation rate is ≥70%. The second stage is a high-temperature zone of 130-140 °C, and the water evaporation rate is ≥99.8%.

4. The method according to claim 3, characterized in that, In step (1), the weight ratio of sea to island in the sea-island fiber is 20:80 to 50:

50.

5. The method according to claim 3, characterized in that, After fibrillation of the waterborne polyurethane sea-island fiber base fabric obtained in step (2), the resin content therein is ≤ 40 wt%.

6. The method according to claim 3, characterized in that In step (1), the sea component of the sea-island fiber is COPET or LDPE, and the island component is PA6 or PET.

7. The method according to claim 3, characterized in that, After needling in step (1), a heat shrinkage setting process is further carried out, and the temperature of the heat shrinkage setting is 90~140 °C.

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