Degradable nonwoven fabric of sisal hemp and wet-laid spunlace and its preparation method

Abstract

This invention relates to a wet-laid hydrospun biodegradable sisal nonwoven fabric and its preparation method. The method is characterized by: firstly, pre-treated sisal fibers are pulped and mixed with PHBV short fibers to obtain a mixed fiber slurry; finally, the wet-laid hydrospun biodegradable sisal nonwoven fabric is prepared using wet web forming, hydrospun, and hot rolling. In the mixed fiber slurry, the mass content of the mixed fibers is 1-5%, with the remainder being water; the mass content of the PHBV short fibers in the mixed fibers is not less than 20%; during hot rolling, the hot rolling temperature is 135-142℃, the conveyor speed is 25-45 m / min, and the pressure roller linear pressure is 300-500 N / cm; the resulting wet-laid hydrospun biodegradable sisal nonwoven fabric has an areal density of 50-70 g / m³. 2 The transverse breaking strength is 60–80 N, the longitudinal breaking strength is 55–70 N, the bursting strength is 50–85 N, and the abrasion resistance index is 90–105 cycles / mg. The method of this invention is simple, and the nonwoven material produced is completely biodegradable and possesses excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of nonwoven technology and relates to a sisal wet-process hydroentangled biodegradable nonwoven fabric and its preparation method. Background Technology

[0002] Current wallpapers use bleached chemical wood pulp to produce base paper, which is then processed through various steps (such as coating, printing, embossing, or surface lamination). The resulting products lack strength and are prone to scratches and damage. Sisal fiber, on the other hand, is white, tough, and strong, possessing properties such as abrasion resistance, acid and alkali resistance, and corrosion resistance. Wallpaper made from sisal fiber is characterized by high strength and abrasion resistance, non-toxicity and odorlessness, sound absorption and moisture resistance, warmth and breathability, resistance to aging, and soft light reflection. Combining the excellent properties of sisal fiber with nonwoven processing technology to prepare high-performance nonwoven materials is a research hotspot in the field of sisal applications. However, due to the coarse, non-curly, and rough surface of sisal fibers, along with horizontal and vertical striations, high fiber stiffness, poor cohesion, and difficulty in fiber entanglement, dry web formation is challenging. Therefore, fine and soft poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fibers are added to improve web formation. PHBV, as an ideal green polymer material, is widely used, with abundant and renewable raw material sources. PHBV short fibers have good biocompatibility, biodegradability and thermal processability.

[0003] Therefore, the problems of sisal fiber being difficult to form into a web by wet processing, hydroentangling reinforcement, and hot rolling can be solved by using PHBV fiber and sisal fiber to form a web, and by using hot rolling to set the web. This can solve the problems of low strength and poor abrasion resistance of existing wallpaper. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a wet-process hydroentangled biodegradable nonwoven fabric of sisal and its preparation method;

[0005] To achieve the above objectives, the present invention adopts the following solution:

[0006] A method for preparing wet-laid hydrospun biodegradable nonwoven fabric of sisal involves first pulping softened pretreated sisal fibers into a slurry and mixing it with PHBV (poly(3-hydroxybutyrate-co-3-hydroxyvalerate)) short fibers to obtain a mixed fiber slurry. Finally, wet-laid, hydrospun, and hot-rolled sizing processes are used to prepare the wet-laid hydrospun biodegradable nonwoven fabric of sisal.

[0007] In the mixed fiber slurry, the mass content of mixed fibers is 1-5%, and the balance is water; in the mixed fibers, the mass content of PHBV short fibers is not less than 20%;

[0008] During hot rolling and setting, the hot rolling temperature is 135-142℃, the conveyor belt speed is 25-45m / min, and the pressure roller linear pressure is 300-500N / cm.

[0009] As a preferred technical solution:

[0010] In the above-described method for preparing a wet-spun hydroentangled biodegradable nonwoven fabric from sisal, the mass content of sisal fiber in the mixed fibers is 30-80%, and the mass content of PHBV short fiber is 20-70%.

[0011] The method for preparing wet-spun hydroentangled biodegradable nonwoven fabric of sisal, as described above, has PHBV short fibers with a fineness of 1.3 to 1.5 dtex and melting points of 137°C and 145°C.

[0012] The preparation method of the above-mentioned wet-process hydroentangling biodegradable nonwoven fabric of sisal includes the following specific preparation steps:

[0013] (1) Preparation of pretreatment solution: Sisal fiber is pretreated by immersing it in an aqueous ethanol solution;

[0014] (2) Preparation of sisal fiber pulp: The pretreated sisal fibers are cut and ground, mixed with water and pulped to obtain sisal fiber pulp;

[0015] (3) Preparation of mixed fiber slurry: Sisal fiber slurry and chopped and ground PHBV short fibers are mixed evenly to obtain mixed fiber slurry;

[0016] (4) Preparation of sisal wet-spun biodegradable nonwoven fabric: The mixed fiber slurry is diluted and fed into the inclined wire forming machine to form a fiber web. Then, the fiber web is pre-wetted, pre-spun, spun, dried, wound, unwound, hot-rolled and shaped, and then wound up to obtain sisal wet-spun biodegradable nonwoven fabric.

[0017] As described above, in the preparation method of sisal wet-spunlace biodegradable nonwoven fabric, in step (1), the ethanol aqueous solution has an ethanol mass fraction of 65-75%, with the remainder being water. Under these parameters, the removal rate of non-cellulose substances in sisal fibers is high. The bath ratio during pretreatment is 1:10-15, and the temperature is 175-190℃. At this temperature, acetic acid is generated, which helps to improve the removal rate of non-cellulose substances. The pretreatment time is 80-120 min. Sisal contains a large amount of non-cellulose substances such as hemicellulose, lignin, and pectin, resulting in coarse, hard sisal fibers with low elasticity and elongation. During dry web forming and needle punching reinforcement, the fibers are not easily entangled, resulting in low web strength. The ethanol aqueous solution has low surface tension at high temperatures and can penetrate into the sisal fibers. Through hydrogen bonding, the ether bonds of the lignin side chains are broken, leading to degradation. During the reaction, the presence of acetyl groups in hemicellulose will generate acetic acid, promoting the removal of lignin and hydrolyzing hemicellulose, thereby achieving the purpose of removing non-cellulose substances. Pretreatment with an ethanol-water solution makes sisal fibers finer, and improves their softness and elongation.

[0018] The above-described method for preparing wet-spun hydroentangled biodegradable nonwoven fabric from sisal significantly improves the properties of the pretreated sisal fibers, with a breaking strength of 160–260 cN, a fineness of 5.5–8 tex, a breaking elongation of 1.6–5%, and a twist count of 85–110 twists / 10 cm.

[0019] In the preparation method of the sisal wet-spun hydroentangled biodegradable nonwoven fabric as described above, in step (2), the pulping concentration is 15-20%, and after pulping, the pulping degree of the sisal fiber pulp is 45-65°SR; in order to ensure the entanglement of fibers in the fiber web and to take into account the uniformity of fiber web formation, the length of the pulped sisal fiber is 2-8mm.

[0020] In the above-mentioned method for preparing a wet-process hydroentangled biodegradable nonwoven fabric of sisal, in step (3), in order to ensure the entanglement of fibers in the fiber web and to take into account the uniformity of the fiber web, the length of the PHBV fibers after cutting and grinding is 3 to 10 mm.

[0021] In the above-mentioned method for preparing a sisal wet-spun hydrospun biodegradable nonwoven fabric, in step (4), the mass content of mixed fibers in the diluted mixed fiber slurry is 0.2-1%; the tilt angle of the inclined wire forming device is 15-20°; the hydrospun pressure is 6-10 MPa; and since the sisal fibers are relatively coarse, the water needle aperture is selected to be 0.3-0.5 mm.

[0022] The sisal wet-spun biodegradable nonwoven fabric prepared by the method described above has an areal density of 50–70 g / m². 2 The transverse breaking strength is 60-80N, the longitudinal breaking strength is 55-70N, the bursting strength is 50-85N, and the abrasion resistance index is 90-105 cycles / mg.

[0023] The principle of this invention is:

[0024] This invention utilizes pretreated sisal fibers, which are then milled and pulped to form sisal pulp, which is then uniformly mixed with PHBV short fibers. This process helps to improve the entanglement between fibers. After the mixed fiber pulp is wet-laid, it is hydroentangled to strengthen the fiber web and give it a certain strength. The nonwoven material made from the mixture of PHBV short fibers and sisal short fibers is completely biodegradable, ensuring that it does not pollute the environment after disposal. Hydroentangled nonwoven fabrics have a rough and uneven surface with low smoothness, while wallpaper requires a smooth, flat, and wear-resistant surface. Therefore, after hydroentanglement, the sisal fiber web is subjected to a hot-rolling and setting process to improve its smoothness and wear resistance.

[0025] Roller temperature, pressure, and hot rolling speed are key factors in hot rolling and setting. High temperature, high pressure, and low speed all promote the melting of the bonding fibers. Melting increases the smoothness and stiffness of nonwoven fabrics, but wallpaper requires a certain degree of flexibility. Therefore, the degree of melting needs to be controlled so that the bonding effect of the nonwoven material is limited to the surface layer. PHBV fiber has a lower melting point than sisal fiber's thermal decomposition point. Through a reasonable hot rolling process, it can be used as both a bonding fiber and an entanglement fiber. When the fiber web enters the hot-rolled bonding zone formed by the rollers, the PHBV short fibers undergo molecular chain movement due to heat. Intense movement can cause the fibers to melt. If the hot-rolling temperature is too high, the molten PHBV short fibers will enter the interior of the fiber web, and the PHBV short fibers inside the fiber web will also melt. Conversely, if the hot-rolling temperature is too low, the PHBV short fibers cannot melt and thus fail to provide bonding. This invention uses a hot-rolling and setting temperature slightly lower than that of the PHBV short fibers. Utilizing the thermal effect generated by the deformation of the fiber web during hot-rolling and setting, the PHBV short fibers located only on the surface of the nonwoven fabric melt, forming surface bonding. Meanwhile, the PHBV fibers inside the fiber web do not melt or melt only slightly. This structure, where the inner layer of PHBV short fibers is entangled with sisal fibers, plays a decisive role in the flexibility and smooth surface properties of the nonwoven material.

[0026] Based on the results of previous experiments, the hot rolling temperature used in this invention is 135-142℃, the conveyor speed is 25-45m / min, and the pressure of the pressure roller is 300-500N / cm. Under these conditions, the PHBV short fibers on the surface of the fiber web melt and flow, diffusing to the surface of the sisal fibers, thereby producing an adhesive effect.

[0027] Beneficial effects

[0028] (1) A method for preparing a wet-spun hydroentangled biodegradable nonwoven fabric of sisal, wherein the treated sisal fibers are milled and pulped to form sisal pulp, which is then uniformly mixed with PHBV short fibers to produce a nonwoven material that is completely biodegradable.

[0029] (2) A sisal wet-spun hydrodegradable nonwoven fabric of the present invention, wherein the areal density of the sisal wet-spun hydrodegradable nonwoven fabric is 50-70 g / m³. 2 The transverse breaking strength is 60-80N, the longitudinal breaking strength is 55-70N, the bursting strength is 50-85N, and the abrasion resistance index is 90-105 cycles / mg. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0031] Example 1

[0032] A method for preparing a wet-process hydroentangled biodegradable nonwoven fabric from sisal, the specific preparation steps are as follows:

[0033] (1) Preparation of pretreatment solution: Sisal fiber is pretreated by immersing it in an ethanol aqueous solution; wherein, the mass fraction of ethanol in the ethanol aqueous solution is 65% and the remainder is water; the bath ratio during pretreatment is 1:10; the pretreatment temperature is 175℃; and the pretreatment time is 117min.

[0034] The pretreated sisal fiber has a breaking strength of 160 cN, a fineness of 5.5 tex, a breaking elongation of 5%, and a twist count of 85 per 10 cm.

[0035] (2) Preparation of sisal fiber pulp: The pretreated sisal fibers are cut, ground, mixed with water and pulped to obtain sisal fiber pulp; the pulping concentration is 15%, the pulping degree of the sisal fiber pulp after pulping is 45°SR; the average length of the pulped sisal fibers is 3mm.

[0036] (3) Preparation of mixed fiber slurry: Sisal fiber slurry and PHBV short fibers with an average length of 4 mm after being cut and ground are mixed evenly to obtain a mixed fiber slurry with a mass content of 1% of the mixed fibers; in the mixed fibers, the mass content of sisal fiber is 80% and the mass content of PHBV short fiber is 20%; the fineness of PHBV short fiber is 1.3 dtex and the melting point of PHBV short fiber is 137℃.

[0037] (4) Preparation of sisal wet-spun biodegradable nonwoven fabric: The mixed fiber slurry was diluted and fed into an inclined wire forming machine to form a fiber web. The fiber web was then subjected to pre-wetting, pre-hydrating, spun, drying, winding, unwinding, hot rolling and setting, and finally winding to obtain the sisal wet-spun biodegradable nonwoven fabric. The mass content of the mixed fibers in the diluted mixed fiber slurry was 0.2%; the inclination angle of the inclined wire forming machine was 15°; the spun pressure was 6 MPa, and the water needle aperture was 0.3 mm. During hot rolling and setting, the hot rolling temperature was 135℃, the wire conveying speed was 25 m / min, and the pressure roller linear pressure was 300 N / cm.

[0038] The resulting wet-processed hydroentangled biodegradable sisal nonwoven fabric has an areal density of 50 g / m². 2The transverse breaking strength is 60N, the longitudinal breaking strength is 55N, the bursting strength is 50N, and the abrasion resistance index is 90 cycles / mg.

[0039] Example 2

[0040] A method for preparing a wet-process hydroentangled biodegradable nonwoven fabric from sisal, the specific preparation steps are as follows:

[0041] (1) Preparation of pretreatment solution: Sisal fiber is pretreated by immersing it in an ethanol aqueous solution; wherein, the mass fraction of ethanol in the ethanol aqueous solution is 71%, and the remainder is water; the bath ratio during pretreatment is 1:14; the pretreatment temperature is 177℃; and the pretreatment time is 110min.

[0042] The pretreated sisal fiber has a breaking strength of 246 cN, a fineness of 8 tex, a breaking elongation of 2%, and a twist count of 99 twists / 10 cm.

[0043] (2) Preparation of sisal fiber pulp: The pretreated sisal fibers are cut, ground, mixed with water and pulped to obtain sisal fiber pulp; the pulping concentration is 18%, and the pulping degree of the sisal fiber pulp after pulping is 47°SR; the average length of the pulped sisal fibers is 3.5mm.

[0044] (3) Preparation of mixed fiber slurry: Sisal fiber slurry and PHBV short fibers with an average length of 4.5 mm after cutting and grinding are mixed evenly to obtain a mixed fiber slurry with a mass content of 4% of the mixed fibers; in the mixed fibers, the mass content of sisal fiber is 80% and the mass content of PHBV short fiber is 20%; the fineness of PHBV short fiber is 1.4 dtex and the melting point of PHBV short fiber is 145℃.

[0045] (4) Preparation of sisal wet-spun biodegradable nonwoven fabric: The mixed fiber slurry was diluted and fed into an inclined wire forming machine to form a fiber web. The fiber web was then subjected to pre-wetting, pre-hydrating, spun, drying, winding, unwinding, hot rolling and setting, and finally winding to obtain the sisal wet-spun biodegradable nonwoven fabric. The mass content of the mixed fibers in the diluted mixed fiber slurry was 0.6%; the inclination angle of the inclined wire forming machine was 15°; the spun pressure was 7 MPa, and the water needle aperture was 0.3 mm. During hot rolling and setting, the hot rolling temperature was 141℃, the wire conveying speed was 27 m / min, and the pressure roller linear pressure was 475 N / cm.

[0046] The areal density of the resulting wet-processed hydroentangled biodegradable sisal nonwoven fabric is 66 g / m². 2 The transverse breaking strength is 74N, the longitudinal breaking strength is 65N, the bursting strength is 75N, and the abrasion resistance index is 96 cycles / mg.

[0047] Example 3

[0048] A method for preparing a wet-process hydroentangled biodegradable nonwoven fabric from sisal, the specific preparation steps are as follows:

[0049] (1) Preparation of pretreatment solution: Sisal fiber is pretreated by immersing it in an ethanol aqueous solution; wherein, the mass fraction of ethanol in the ethanol aqueous solution is 72% and the remainder is water; the bath ratio during pretreatment is 1:10; the pretreatment temperature is 190℃; and the pretreatment time is 82min.

[0050] The pretreated sisal fiber has a breaking strength of 259 cN, a fineness of 7 tex, a breaking elongation of 1.7%, and a twist count of 105 / 10cm.

[0051] (2) Preparation of sisal fiber pulp: The pretreated sisal fibers are cut, ground, mixed with water and pulped to obtain sisal fiber pulp; the pulping concentration is 16%, the pulping degree of the sisal fiber pulp after pulping is 45°SR; the average length of the pulped sisal fibers is 4mm.

[0052] (3) Preparation of mixed fiber slurry: Sisal fiber slurry and PHBV short fibers with an average length of 4.5 mm after cutting and grinding are mixed evenly to obtain a mixed fiber slurry with a mass content of 5% of the mixed fibers; in the mixed fibers, the mass content of sisal fiber is 75% and the mass content of PHBV short fiber is 25%; the fineness of PHBV short fiber is 1.3 dtex and the melting point of PHBV short fiber is 145℃.

[0053] (4) Preparation of sisal wet-spun biodegradable nonwoven fabric: The mixed fiber slurry was diluted and fed into an inclined wire forming machine to form a fiber web. The fiber web was then subjected to pre-wetting, pre-hydrating, spun, drying, winding, unwinding, hot rolling and setting, and finally winding to obtain the sisal wet-spun biodegradable nonwoven fabric. The mass content of the mixed fibers in the diluted mixed fiber slurry was 0.8%; the inclination angle of the inclined wire forming machine was 17°; the spun pressure was 6 MPa, and the water needle aperture was 0.3 mm. During hot rolling and setting, the hot rolling temperature was 141℃, the wire conveying speed was 30 m / min, and the pressure roller linear pressure was 350 N / cm.

[0054] The areal density of the resulting wet-processed hydroentangled biodegradable sisal nonwoven fabric is 68 g / m². 2 The transverse breaking strength is 79N, the longitudinal breaking strength is 68N, the bursting strength is 81N, and the abrasion resistance index is 100 cycles / mg.

[0055] Example 4

[0056] A method for preparing a wet-process hydroentangled biodegradable nonwoven fabric from sisal, the specific preparation steps are as follows:

[0057] (1) Preparation of pretreatment solution: Sisal fiber is pretreated by immersing it in an ethanol aqueous solution; wherein, the mass fraction of ethanol in the ethanol aqueous solution is 66% and the remainder is water; the bath ratio during pretreatment is 1:15; the pretreatment temperature is 175℃; and the pretreatment time is 120min.

[0058] The pretreated sisal fiber has a breaking strength of 172 cN, a fineness of 5.8 tex, a breaking elongation of 4.5%, and a twist count of 85 per 10 cm.

[0059] (2) Preparation of sisal fiber pulp: The pretreated sisal fibers are cut, ground, mixed with water and pulped to obtain sisal fiber pulp; the pulping concentration is 15%, the pulping degree of the sisal fiber pulp after pulping is 62°SR; the average length of the pulped sisal fibers is 4mm.

[0060] (3) Preparation of mixed fiber slurry: Sisal fiber slurry and PHBV short fibers with an average length of 5 mm after being cut and ground are mixed evenly to obtain a mixed fiber slurry with a mass content of 2% of the mixed fibers; in the mixed fibers, the mass content of sisal fiber is 75% and the mass content of PHBV short fiber is 25%; the fineness of PHBV short fiber is 1.5 dtex and the melting point of PHBV short fiber is 137℃.

[0061] (4) Preparation of sisal wet-spun biodegradable nonwoven fabric: The mixed fiber slurry was diluted and fed into an inclined wire forming machine to form a fiber web. The fiber web was then subjected to pre-wetting, pre-hydrating, spun, drying, winding, unwinding, hot rolling and setting, and finally winding to obtain the sisal wet-spun biodegradable nonwoven fabric. The mass content of the mixed fibers in the diluted mixed fiber slurry was 0.2%; the inclination angle of the inclined wire forming machine was 15°; the spun pressure was 8 MPa, and the water needle aperture was 0.4 mm. During hot rolling and setting, the hot rolling temperature was 134℃, the wire conveying speed was 25 m / min, and the pressure roller linear pressure was 310 N / cm.

[0062] The areal density of the resulting wet-processed hydroentangled biodegradable sisal nonwoven fabric is 54 g / m². 2 The transverse breaking strength is 65N, the longitudinal breaking strength is 58N, the bursting strength is 65N, and the abrasion resistance index is 91 cycles / mg.

[0063] Example 5

[0064] A method for preparing a wet-process hydroentangled biodegradable nonwoven fabric from sisal, the specific preparation steps are as follows:

[0065] (1) Preparation of pretreatment solution: Sisal fiber is pretreated by immersing it in an ethanol aqueous solution; wherein, the mass fraction of ethanol in the ethanol aqueous solution is 71%, and the remainder is water; the bath ratio during pretreatment is 1:13; the pretreatment temperature is 188℃; and the pretreatment time is 84min.

[0066] The pretreated sisal fiber has a breaking strength of 190 cN, a fineness of 7.2 tex, a breaking elongation of 3.7%, and a twist count of 96 per 10 cm.

[0067] (2) Preparation of sisal fiber pulp: The pretreated sisal fibers are cut, ground, mixed with water and pulped to obtain sisal fiber pulp; the pulping concentration is 20%, and the pulping degree of the sisal fiber pulp after pulping is 50°SR; the average length of the pulped sisal fibers is 4.5mm.

[0068] (3) Preparation of mixed fiber slurry: Sisal fiber slurry and PHBV short fibers with an average length of 5 mm after being cut and ground are mixed evenly to obtain a mixed fiber slurry with a mass content of 5% of the mixed fibers; in the mixed fibers, the mass content of sisal fiber is 55% and the mass content of PHBV short fiber is 45%; the fineness of PHBV short fiber is 1.4 dtex and the melting point of PHBV short fiber is 137℃.

[0069] (4) Preparation of sisal wet-spun biodegradable nonwoven fabric: The mixed fiber slurry was diluted and fed into an inclined wire forming machine to form a fiber web. The fiber web was then subjected to pre-wetting, pre-hydrating, spun, drying, winding, unwinding, hot rolling and setting, and finally rewinding to obtain the sisal wet-spun biodegradable nonwoven fabric. The mass content of the mixed fibers in the diluted mixed fiber slurry was 0.5%; the inclination angle of the inclined wire forming machine was 19°; the spun pressure was 10 MPa, and the water needle aperture was 0.3 mm. During hot rolling and setting, the hot rolling temperature was 135℃, the wire conveying speed was 29 m / min, and the pressure roller linear pressure was 420 N / cm.

[0070] The resulting wet-processed hydroentangled biodegradable sisal nonwoven fabric has an areal density of 62 g / m². 2 The transverse breaking strength is 71N, the longitudinal breaking strength is 62N, the bursting strength is 72N, and the abrasion resistance index is 94 cycles / mg.

[0071] Example 6

[0072] A method for preparing a wet-process hydroentangled biodegradable nonwoven fabric from sisal, the specific preparation steps are as follows:

[0073] (1) Preparation of pretreatment solution: Sisal fiber is pretreated by immersing it in an ethanol aqueous solution; wherein, the mass fraction of ethanol in the ethanol aqueous solution is 68%, and the remainder is water; the bath ratio during pretreatment is 1:10; the pretreatment temperature is 176℃; and the pretreatment time is 114min.

[0074] The pretreated sisal fiber has a breaking strength of 226 cN, a fineness of 5.6 tex, a breaking elongation of 2.1%, and a twist count of 86 / 10 cm.

[0075] (2) Preparation of sisal fiber pulp: The pretreated sisal fibers are cut, ground, mixed with water and pulped to obtain sisal fiber pulp; the pulping concentration is 18%, and the pulping degree of the sisal fiber pulp after pulping is 63°SR; the average length of the pulped sisal fibers is 4.5mm.

[0076] (3) Preparation of mixed fiber slurry: Sisal fiber slurry and PHBV short fibers with an average length of 6 mm after being cut and ground are mixed evenly to obtain a mixed fiber slurry with a mass content of 5% of the mixed fibers; in the mixed fibers, the mass content of sisal fiber is 50% and the mass content of PHBV short fiber is 50%; the fineness of PHBV short fiber is 1.4 dtex and the melting point of PHBV short fiber is 145℃.

[0077] (4) Preparation of sisal wet-spun biodegradable nonwoven fabric: The mixed fiber slurry was diluted and fed into an inclined wire forming machine to form a fiber web. The fiber web was then subjected to pre-wetting, pre-hydrating, spun, drying, winding, unwinding, hot rolling and setting, and finally winding to obtain the sisal wet-spun biodegradable nonwoven fabric. The mass content of the mixed fibers in the diluted mixed fiber slurry was 0.7%; the inclination angle of the inclined wire forming machine was 16°; the spun pressure was 8 MPa, and the water needle aperture was 0.4 mm. During hot rolling and setting, the hot rolling temperature was 140℃, the wire conveying speed was 30 m / min, and the pressure roller linear pressure was 470 N / cm.

[0078] The resulting wet-processed hydroentangled biodegradable sisal nonwoven fabric has an areal density of 67 g / m². 2 The transverse breaking strength is 76N, the longitudinal breaking strength is 66N, the bursting strength is 78N, and the abrasion resistance index is 98 cycles / mg.

[0079] Example 7

[0080] A method for preparing a wet-process hydroentangled biodegradable nonwoven fabric from sisal, the specific preparation steps are as follows:

[0081] (1) Preparation of pretreatment solution: Sisal fiber is pretreated by immersing it in an ethanol aqueous solution; wherein, the mass fraction of ethanol in the ethanol aqueous solution is 70%, and the remainder is water; the bath ratio during pretreatment is 1:11; the pretreatment temperature is 185℃; and the pretreatment time is 84min.

[0082] The pretreated sisal fiber has a breaking strength of 183 cN, a fineness of 6.1 tex, a breaking elongation of 4%, and a twist count of 88 twists / 10 cm.

[0083] (2) Preparation of sisal fiber pulp: The pretreated sisal fibers are cut, ground, mixed with water and pulped to obtain sisal fiber pulp; the pulping concentration is 18%, the pulping degree of the sisal fiber pulp after pulping is 61°SR; the average length of the pulped sisal fibers is 5mm.

[0084] (3) Preparation of mixed fiber slurry: Sisal fiber slurry and PHBV short fibers with an average length of 6 mm after being cut and ground are mixed evenly to obtain a mixed fiber slurry with a mass content of 1% of the mixed fibers; in the mixed fibers, the mass content of sisal fiber is 45% and the mass content of PHBV short fiber is 55%; the fineness of PHBV short fiber is 1.3 dtex and the melting point of PHBV short fiber is 145℃.

[0085] (4) Preparation of sisal wet-spun biodegradable nonwoven fabric: The mixed fiber slurry was diluted and fed into an inclined wire forming machine to form a fiber web. The fiber web was then subjected to pre-wetting, pre-hydrating, spun, drying, winding, unwinding, hot rolling and setting, and finally winding to obtain the sisal wet-spun biodegradable nonwoven fabric. The mass content of the mixed fibers in the diluted mixed fiber slurry was 0.4%; the inclination angle of the inclined wire forming machine was 16°; the spun pressure was 9 MPa, and the water needle aperture was 0.3 mm. During hot rolling and setting, the hot rolling temperature was 140℃, the wire conveying speed was 33 m / min, and the pressure roller linear pressure was 340 N / cm.

[0086] The areal density of the resulting wet-processed hydroentangled biodegradable sisal nonwoven fabric is 57 g / m². 2 The transverse breaking strength is 68N, the longitudinal breaking strength is 60N, the bursting strength is 68N, and the abrasion resistance index is 92 cycles / mg.

[0087] Example 8

[0088] A method for preparing a wet-process hydroentangled biodegradable nonwoven fabric from sisal, the specific preparation steps are as follows:

[0089] (1) Preparation of pretreatment solution: Sisal fiber is pretreated by immersing it in an ethanol aqueous solution; wherein, the mass fraction of ethanol in the ethanol aqueous solution is 75% and the remainder is water; the bath ratio during pretreatment is 1:15; the pretreatment temperature is 190℃; and the pretreatment time is 80min.

[0090] The pretreated sisal fiber has a breaking strength of 260 cN, a fineness of 8 tex, a breaking elongation of 1.6%, and a twist count of 110 / 10 cm.

[0091] (2) Preparation of sisal fiber pulp: The pretreated sisal fibers are cut, ground, mixed with water and pulped to obtain sisal fiber pulp; wherein, the pulping concentration is 20%, and the pulping degree of the sisal fiber pulp after pulping is 65°SR; the average length of the pulped sisal fibers is 5mm.

[0092] (3) Preparation of mixed fiber slurry: Sisal fiber slurry and PHBV short fibers with an average length of 7 mm after being cut and ground are mixed evenly to obtain a mixed fiber slurry with a mass content of 5% of the mixed fibers; in the mixed fibers, the mass content of sisal fiber is 30% and the mass content of PHBV short fiber is 70%; the fineness of PHBV short fiber is 1.5 dtex and the melting point of PHBV short fiber is 145℃.

[0093] (4) Preparation of sisal wet-spun biodegradable nonwoven fabric: The mixed fiber slurry was diluted and fed into an inclined wire forming machine to form a fiber web. The fiber web was then subjected to pre-wetting, pre-hydrating, spun, drying, winding, unwinding, hot rolling and setting, and finally winding to obtain the sisal wet-spun biodegradable nonwoven fabric. The mass content of the mixed fibers in the diluted mixed fiber slurry was 1%; the inclination angle of the inclined wire forming machine was 20°; the spun pressure was 10 MPa, and the water needle aperture was 0.5 mm. During hot rolling and setting, the hot rolling temperature was 142℃, the wire conveying speed was 45 m / min, and the pressure roller linear pressure was 500 N / cm.

[0094] The resulting wet-processed hydroentangled biodegradable sisal nonwoven fabric has an areal density of 70 g / m². 2 The transverse breaking strength is 80N, the longitudinal breaking strength is 70N, the bursting strength is 85N, and the abrasion resistance index is 105 cycles / mg.

Claims

1. A process for the production of a degradable nonwoven fabric of wet-laid sisal hemp, characterized by: The soft pretreated sisal fibers are beaten into pulp and mixed with PHBV short fibers to obtain a mixed fiber slurry, and then a wet-laid, spunlace and hot-rolled process is adopted to prepare the sisal wet-spun degradable nonwoven fabric. In the mixed fiber slurry, the mass content of the mixed fibers is 1-5%, and the rest is water; in the mixed fibers, the mass content of the PHBV short fibers is not less than 20%. In the hot-rolling process, the hot-rolling temperature is 135-142℃, the web conveying speed is 25-45m / min, and the line pressure of the compression roller is 300-500N / cm. In the hot-rolling process, the hot-rolling pressure and speed are selected to make the heat effect generated by the deformation of the fiber web melt the PHBV short fibers only on the surface of the sisal wet-spun degradable nonwoven fabric to form surface bonding, while the PHBV fibers in the interior of the fiber web do not melt or melt a little, and the inner PHBV short fibers are entangled with the sisal fibers. The soft pretreatment of the sisal fibers refers to immersing the sisal fibers in an ethanol aqueous solution for pretreatment; the pretreatment temperature is 175-190℃; and the pretreatment time is 80-120min. The face density of the degradable nonwoven fabric of the wet-laid pina is 50-70 g / m 2 , the transverse breaking strength is 60-80 N, the longitudinal breaking strength is 55-70 N, the bursting strength is 50-85 N, and the wear resistance index is 90-105 times / mg.

2. A process for the production of a degradable nonwoven fabric of sisal hemp by wet-lap process as claimed in claim 1, wherein, In the mixed fibers, the mass content of the sisal fibers is 30-80%, and the mass content of the PHBV short fibers is 20-70%.

3. A process for the production of a degradable nonwoven fabric of sisal hemp by wet-laplace according to claim 1, characterized in that, The fineness of the PHBV short fibers is 1.3-1.5dtex, and the melting point of the PHBV short fibers is 137℃ and 145℃.

4. The process for the production of a degradable nonwoven fabric of sisal hemp by wet-laplace according to claim 1, characterized in that, The specific preparation steps are as follows: (1) preparing a pretreatment solution: immersing the sisal fibers in an ethanol aqueous solution for pretreatment; (2) preparing a sisal fiber pulp: cutting and grinding the pretreated sisal fibers, mixing with water and beating to obtain a sisal fiber pulp; (3) preparing a mixed fiber slurry: uniformly mixing the sisal fiber pulp and the cut and ground PHBV short fibers to obtain a mixed fiber slurry; (4) preparing a sisal wet-spun degradable nonwoven fabric: diluting the mixed fiber slurry and feeding into an inclined web former to form a fiber web, and then sequentially performing pre-wetting, pre-spunlacing, spunlacing, drying, winding, unwinding, hot-rolling, and collecting to obtain a sisal wet-spun degradable nonwoven fabric.

5. A process for the production of a degradable nonwoven fabric of sisal hemp by wet-lap process as claimed in claim 4, wherein the said process is characterized by, In step (1), in the ethanol aqueous solution, the mass fraction of ethanol is 65-75%, and the rest is water; and the bath ratio in the pretreatment is 1:10-15.

6. A process for the production of a degradable nonwoven fabric of sisal hemp by wet-lap process as claimed in claim 4, wherein the said process is characterized by the steps of: In step (2), the beating consistency is 15-20%, and after beating, the beating degree of the sisal fiber pulp is 45-65°SR; and the length of the beaten sisal fibers is 2-8mm.

7. A process for the production of a degradable nonwoven fabric of sisal hemp by wet-lap process as claimed in claim 4, wherein the said process is characterized by, In step (3), the length of the cut and ground PHBV fibers is 3-10mm.

8. A process for the production of a degradable nonwoven fabric of sisal hemp by wet-laplace hydroentanglement according to claim 4, characterized in that, In step (4), in the diluted mixed fiber slurry, the mass content of the mixed fibers is 0.2-1%; the inclination angle of the inclined web former is 15-20°; the pressure of the spunlacing is 6-10Mpa, and the water needle aperture is 0.3-0.5mm.

9. A process for the production of a degradable nonwoven fabric of sisal hemp by wet-laplace hydroentanglement according to claim 4, characterized in that, The breaking strength of the pretreated sisal fibers is 160-260cN, the fineness is 5.5-8tex, the breaking elongation is 1.6-5%, and the twist turns are 85-110 / 10cm.