Polylactic acid composite fiber for diapers and preparation method thereof

Abstract

The invention relates to the technical field of fibers, and discloses a polylactic acid composite fiber for diapers and a preparation method thereof. The polylactic acid composite fiber comprises the following raw materials: polylactic acid, a montmorillonite additive, an antibacterial additive, a lubricant, cellulose acetate, and natural plant fiber. The polylactic acid is used as a matrix material, the montmorillonite additive is prepared by reacting modified montmorillonite with dextran, and can effectively improve the water absorption effect of the polylactic acid composite fiber. The antibacterial additive component is prepared by reacting carbonate diol with epoxy POSS and an antibacterial agent, and can effectively enhance the antibacterial property and mechanical property of the polylactic acid composite fiber. The invention prepares the polylactic acid composite fiber by combining polylactic acid with the montmorillonite additive and the antibacterial additive, and has excellent water absorption and antibacterial properties, and meets the use requirements of diapers.

Description

Technical Field

[0001] The present invention relates to the field of fiber technology, in particular to a polylactic acid composite fiber for diapers and a preparation method thereof. Background Art

[0002] Diapers are daily necessities for infants and children or those with limited mobility. Currently, traditional diapers are mainly made of non-woven fabrics, super absorbent resins, PE films and other materials. They are highly absorbent, soft and comfortable, and do not irritate the skin. They have the advantages of short process flow, fast production speed, high output, low cost, wide application, and multiple sources of raw materials. However, traditional diapers are not environmentally friendly. Polylactic acid is a polyester polymerized from lactic acid. It comes from bio-based raw materials, such as corn, cassava, sugarcane and other starch-rich crops. As a completely biodegradable and environmentally friendly polyester compound, it has a wide range of sources. Polylactic acid fiber made from polylactic acid is an environmentally friendly and completely biodegradable synthetic fiber that can be completely degraded into carbon dioxide and water It does not produce toxic gas when burned, does not cause pollution, is non-toxic and non-irritating, and is a renewable resource. In addition, polylactic acid fiber has many advantages such as good hydrophilicity, good air permeability, good hand feel and high comfort, good resilience, controllable shrinkage, good molding and processing, low flammability, small smoke emission, washing resistance, good biocompatibility, and excellent mechanical properties. It is widely used in non-woven fabrics, clothing, home decoration, health care, daily necessities, packaging materials and other fields, and has broad application prospects. Therefore, polylactic acid fiber can be used as a material for making diapers, but the water absorption and antibacterial properties of polylactic acid fiber are relatively poor, and other components need to be added to make polylactic acid composite fibers to meet the standards required for diaper products.

[0003] The patent with publication number CN114182435A discloses a polylactic acid antibacterial composite fiber membrane and its preparation method and application. A silver source is mixed with tea polyphenols and water to perform a reduction reaction to prepare a composite antibacterial agent. The composite antibacterial agent is mixed with polylactic acid, a solvent and a coupling agent to obtain a skin spinning solution. The polylactic acid is mixed with a solvent to obtain a core spinning solution. The skin spinning solution and the core spinning solution are coaxially electrospun to obtain a polylactic acid antibacterial composite fiber membrane, thereby improving the antibacterial properties of the polylactic acid composite fiber membrane. However, the patent does not solve the problem of water absorption of the polylactic acid composite fiber and it cannot be used as a material for diapers. For this reason, the present invention proposes a polylactic acid composite fiber for diapers and a preparation method thereof. Summary of the invention

[0004] The purpose of the present invention is to provide a polylactic acid composite fiber for diapers and a preparation method thereof. The following technical problems are solved:

[0005] (1) Solved the problem of poor water absorption of polylactic acid composite fibers;

[0006] (2) The problem of poor antibacterial properties of polylactic acid composite fibers has been solved.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A polylactic acid composite fiber for diapers comprises the following raw materials in parts by weight: 70-100 parts of polylactic acid, 4-10 parts of montmorillonite additive, 1-8 parts of antibacterial additive, 1-5 parts of lubricant, 5-15 parts of cellulose acetate and 10-30 parts of natural plant fiber.

[0009] Furthermore, the preparation method of the montmorillonite additive is:

[0010] Step A, adding montmorillonite to deionized water, stirring for 15-30 minutes, adding succinic anhydride, heating to 60-80° C., reacting for 1-2 hours, filtering, washing, and drying to obtain modified montmorillonite;

[0011] Step B: Disperse the modified montmorillonite evenly in N,N-dimethylformamide solution, add dextran and p-toluenesulfonic acid, stir evenly, heat to 90-100° C., react for 1-2 hours, discharge, and obtain montmorillonite additive.

[0012] By adopting the above technical scheme, the hydroxyl groups on the surface of montmorillonite are modified by succinic anhydride, and active carboxyl groups are introduced on the surface of montmorillonite to obtain modified montmorillonite. Under the action of a catalyst, these active carboxyl groups can react with the active hydroxyl groups in the glucan structure to obtain a montmorillonite additive.

[0013] Furthermore, the particle size of the montmorillonite is 3-5 μm.

[0014] Furthermore, the lubricant is fatty alcohol polyoxyethylene ether or ethylene bisstearamide.

[0015] Furthermore, the preparation method of the antibacterial additive is:

[0016] Ⅰ: Add polycarbonate diol and epoxy POSS to n-octane solution, disperse evenly, add catalyst, heat to 60-80°C, react for 7-9h, separate, wash and dry to obtain substance A;

[0017] II: Add substance A and the antibacterial agent to N,N-dimethylformamide solution, stir evenly, add p-toluenesulfonic acid, heat to 50-60°C, react for 2-4h, wash, and dry to obtain an antibacterial additive.

[0018] By adopting the above technical scheme, the hydroxyl group at one end of the polycarbonate diol structure and the epoxy group of the epoxy POSS can undergo a ring-opening reaction under the action of a catalyst to generate substance A, and the hydroxyl group at the other end of the polycarbonate diol structure in substance A can continue to undergo an esterification reaction with the carboxyl group in the antibacterial agent structure to obtain an antibacterial additive.

[0019] Furthermore, the catalyst in Ⅰ is tetrabutylammonium bromide or tetrabutylammonium chloride.

[0020] Furthermore, the antibacterial agent in Ⅱ is guanidinopropionic acid or guanidinoacetic acid.

[0021] A method for preparing polylactic acid composite fibers for diapers comprises the following steps:

[0022] Step 1: adding polylactic acid, montmorillonite additive, antibacterial agent additive, lubricant, cellulose acetate, and natural plant fiber into a mixer and uniformly dispersing them to obtain a mixture;

[0023] Step 2: melt-blending, extruding and vacuum-drying the mixture through a twin-screw extruder and then spinning it on a melt spinning machine to obtain polylactic acid composite fibers.

[0024] Furthermore, the spinning temperature is 180-230° C., the winding speed is 1400-2000 m / min, the drawing temperature is 70-90° C., and the drawing multiple is 2.5-4.5 times.

[0025] Beneficial effects of the present invention:

[0026] (1) The montmorillonite additive prepared by the present invention has excellent water absorption performance. The surface of the montmorillonite modified with dextran contains a polymer modification layer, which can produce a strong interface bonding with the polylactic acid matrix, thereby avoiding shedding and loss of water absorption, which helps to keep the skin dry and comfortable.

[0027] (2) The antibacterial additive prepared by the present invention contains a branched structure. Since polycarbonate and polylactic acid have similar structures, they can extend to various regions of the polylactic acid matrix, fix POSS in the polylactic acid matrix, and produce a physical cross-linking effect, thereby combining the advantages of POSS and effectively enhancing the mechanical properties of the polylactic acid fiber. In addition, the presence of guanidine groups can have a good antibacterial effect, and after chemical grafting, they can exist in the polylactic acid fiber for a long time, avoiding the loss of antibacterial properties caused by volatilization and migration.

[0028] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0030] Figure 1 The infrared spectrum of the montmorillonite additive in the embodiment of the present invention is shown in FIG.

[0031] Figure 2 It is the infrared spectrum of the antibacterial additive in the embodiment of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] A polylactic acid composite fiber for diapers comprises the following raw materials in parts by weight: 70 g of polylactic acid, 4 g of montmorillonite additive, 2 g of antibacterial additive, 2 g of ethylene bisstearamide, 5 g of cellulose acetate and 10 g of hemp fiber.

[0035] A method for preparing a polylactic acid composite fiber for diapers comprises the following steps:

[0036] Step 1, adding polylactic acid, montmorillonite additive, antibacterial agent additive, ethylene bisstearamide, cellulose acetate, and hemp fiber into a mixer and uniformly dispersing them to obtain a mixture;

[0037] Step 2: melt-blending, extruding and vacuum-drying the mixture through a twin-screw extruder and then spinning it on a melt spinning machine to obtain polylactic acid composite fibers. The spinning temperature is 180°C, the winding speed is 1500m / min, the drawing temperature is 70°C, and the drawing multiple is 2.5 times.

[0038] The preparation method of the montmorillonite additive comprises the following steps:

[0039] Step A, adding 4 g of montmorillonite to 50 mL of deionized water, stirring for 15 min, adding 6 g of succinic anhydride, reacting for 1.5 h, filtering, washing, and drying to obtain modified montmorillonite;

[0040] Step B: Disperse 3 g of modified montmorillonite evenly in 50 mL of N,N-dimethylformamide solution, add 5 g of dextran and 0.2 g of p-toluenesulfonic acid, stir evenly, heat to 95° C., react for 1.5 h, and discharge to obtain a montmorillonite additive.

[0041] The montmorillonite additive was mixed with potassium bromide and ground, and then tableted. The montmorillonite additive was tested by infrared spectrometer using Fourier transform infrared spectrometer. Figure 1 As shown, the spectral wavenumber test range is 4000cm -1 ~500cm -1 According to the analysis, in the infrared spectrum of montmorillonite additives, 1732cm -1 The absorption peak of the carbon-oxygen double bond of the ester group is 1028 cm -1 The absorption peak of silicon-oxygen bond is at 1732cm -1 The appearance of the absorption peak of the ester carbon-oxygen double bond indicates that dextran has been successfully grafted onto the modified montmorillonite and the montmorillonite additive has been successfully prepared.

[0042] The preparation method of the antibacterial additive comprises the following steps:

[0043] Ⅰ: Add 10g of polycarbonate diol and 6g of epoxy POSS to 50mL of n-octane solution, add 0.5g of tetrabutylammonium bromide, raise the temperature to 70°C, react for 8h, separate, wash and dry to obtain substance A;

[0044] Ⅱ: Take 6g of substance A and 10g of guanidine propionic acid antibacterial agent and add them to 50mL of N,N-dimethylformamide solution. After stirring evenly, add 0.25g of p-toluenesulfonic acid, heat to 60℃, react for 3h, wash and dry to obtain the antibacterial additive.

[0045] The antibacterial additives were mixed with potassium bromide and ground into tablets, and then the tablets were pressed. The antibacterial additives were tested by infrared spectrometer using Fourier transform infrared spectrometer. Figure 2 As shown, the spectral wavenumber test range is 4000cm -1 ~500cm -1 , analysis shows that in the infrared spectrum of substance A, 3340cm -1 The absorption peak of hydroxyl is 1740cm -1 The absorption peak of the carbon-oxygen double bond of the ester group is 1040 cm -1 The absorption peak of silicon-oxygen bond is 3335cm in the infrared spectrum of antibacterial additives. -1 The absorption peak of hydroxyl is at 3250cm -1 The absorption peak of nitrogen-hydrogen bond in the guanidine structure was found, indicating that the antibacterial additive was successfully prepared.

[0046] Example 2

[0047] A polylactic acid composite fiber for diapers comprises the following raw materials in parts by weight: 80 g of polylactic acid, 6 g of montmorillonite additive, 4 g of antibacterial additive, 3 g of ethylene bisstearamide, 7 g of cellulose acetate and 15 g of hemp fiber.

[0048] A method for preparing a polylactic acid composite fiber for diapers comprises the following steps:

[0049] Step 1, adding polylactic acid, montmorillonite additive, antibacterial agent additive, ethylene bisstearamide, cellulose acetate, and hemp fiber into a mixer and uniformly dispersing them to obtain a mixture;

[0050] Step 2: melt-blending, extruding and vacuum-drying the mixture through a twin-screw extruder and then spinning it on a melt spinning machine to obtain polylactic acid composite fibers. The spinning temperature is 190°C, the winding speed is 1600m / min, the drawing temperature is 75°C, and the drawing multiple is 3 times.

[0051] The preparation methods of the montmorillonite additive and the antibacterial additive are the same as those in Example 1.

[0052] Example 3

[0053] A polylactic acid composite fiber for diapers comprises the following raw materials in parts by weight: 90 g of polylactic acid, 8 g of montmorillonite additive, 6 g of antibacterial additive, 4 g of ethylene bisstearamide, 9 g of cellulose acetate and 20 g of hemp fiber.

[0054] A method for preparing a polylactic acid composite fiber for diapers comprises the following steps:

[0055] Step 1, adding polylactic acid, montmorillonite additive, antibacterial agent additive, ethylene bisstearamide, cellulose acetate, and hemp fiber into a mixer and uniformly dispersing them to obtain a mixture;

[0056] Step 2: melt-blending, extruding and vacuum-drying the mixture through a twin-screw extruder and then spinning it on a melt spinning machine to obtain polylactic acid composite fibers. The spinning temperature is 200°C, the winding speed is 1700m / min, the drawing temperature is 80°C, and the drawing multiple is 3.5 times.

[0057] The preparation methods of the montmorillonite additive and the antibacterial additive are the same as those in Example 1.

[0058] Example 4

[0059] A polylactic acid composite fiber for diapers comprises the following raw materials in parts by weight: 100 g of polylactic acid, 10 g of montmorillonite additive, 8 g of antibacterial additive, 5 g of ethylene bisstearamide, 12 g of cellulose acetate and 30 g of hemp fiber.

[0060] A method for preparing a polylactic acid composite fiber for diapers comprises the following steps:

[0061] Step 1, adding polylactic acid, montmorillonite additive, antibacterial agent additive, ethylene bisstearamide, cellulose acetate, and hemp fiber into a mixer and uniformly dispersing them to obtain a mixture;

[0062] Step 2: melt-blending, extruding and vacuum-drying the mixture through a twin-screw extruder and then spinning it on a melt spinning machine to obtain polylactic acid composite fibers. The spinning temperature is 210° C., the winding speed is 1800 m / min, the drawing temperature is 85° C., and the drawing multiple is 4 times.

[0063] The preparation methods of the montmorillonite additive and the antibacterial additive are the same as those in Example 1.

[0064] Comparative Example 1

[0065] A polylactic acid composite fiber for diapers comprises the following raw materials in parts by weight: 80 g of polylactic acid, 6 g of an antibacterial additive, 3 g of ethylene bisstearamide, 7 g of cellulose acetate, and 15 g of hemp fiber.

[0066] A method for preparing a polylactic acid composite fiber for diapers comprises the following steps:

[0067] Step 1, adding polylactic acid, antibacterial additive, ethylene bisstearamide, cellulose acetate, and hemp fiber into a mixer and uniformly dispersing them to obtain a mixture;

[0068] Step 2: melt-blending, extruding and vacuum-drying the mixture through a twin-screw extruder and then spinning it on a melt spinning machine to obtain polylactic acid composite fibers. The spinning temperature is 190°C, the winding speed is 1600m / min, the drawing temperature is 75°C, and the drawing multiple is 3 times.

[0069] The preparation method of the antibacterial additive is the same as that in Example 1.

[0070] Comparative Example 2

[0071] A polylactic acid composite fiber for diapers comprises the following raw materials in parts by weight: 80 g of polylactic acid, 6 g of montmorillonite additive, 3 g of ethylene bisstearamide, 7 g of cellulose acetate and 15 g of hemp fiber.

[0072] A method for preparing a polylactic acid composite fiber for diapers comprises the following steps:

[0073] Step 1, adding polylactic acid, montmorillonite additive, ethylene bisstearamide, cellulose acetate, and hemp fiber into a mixer and uniformly dispersing them to obtain a mixture;

[0074] Step 2: melt-blending, extruding and vacuum-drying the mixture through a twin-screw extruder and then spinning it on a melt spinning machine to obtain polylactic acid composite fibers. The spinning temperature is 190°C, the winding speed is 1600m / min, the drawing temperature is 75°C, and the drawing multiple is 3 times.

[0075] The preparation method of the montmorillonite additive is the same as that in Example 1.

[0076] Comparative Example 3

[0077] A polylactic acid composite fiber for diapers comprises the following raw materials in parts by weight: 80 g of polylactic acid, 6 g of montmorillonite additive, 4 g of epoxy POSS, 3 g of ethylene bisstearamide, 7 g of cellulose acetate and 15 g of hemp fiber.

[0078] A method for preparing a polylactic acid composite fiber for diapers comprises the following steps:

[0079] Step 1, adding polylactic acid, montmorillonite additive, epoxy POSS, ethylene bis stearamide, cellulose acetate, and hemp fiber into a mixer and uniformly dispersing them to obtain a mixture;

[0080] Step 2: melt-blending, extruding and vacuum-drying the mixture through a twin-screw extruder and then spinning it on a melt spinning machine to obtain polylactic acid composite fibers. The spinning temperature is 190°C, the winding speed is 1600m / min, the drawing temperature is 75°C, and the drawing multiple is 3 times.

[0081] The preparation method of the montmorillonite additive is the same as that in Example 1.

[0082] Performance Testing

[0083] Performance test of polylactic acid composite fibers for diapers prepared in Examples 1 to 4 of the present invention and Comparative Examples 1 to 3:

[0084] The specific test results are shown in the table below:

[0085]

[0086] It can be seen from the data in the above table that the polylactic acid composite fibers for diapers prepared in Examples 1 to 4 of the present invention have the advantages of high strength, strong water absorption, strong antibacterial properties, good air permeability, etc. Comparative Example 1 did not add montmorillonite additives, and the water absorption performance of the composite fibers was poor. Comparative Example 2 did not add antibacterial additives, and the antibacterial properties of the composite fibers were poor.

[0087] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A polylactic acid composite fiber for diapers, characterized in that: The invention comprises the following raw materials in parts by weight: 70-100 parts of polylactic acid, 4-10 parts of montmorillonite additive, 1-8 parts of antibacterial additive, 1-5 parts of lubricant, 5-15 parts of cellulose acetate and 10-30 parts of natural plant fiber; The preparation method of the montmorillonite additive is: Step A, adding montmorillonite to deionized water, stirring for 15-30 minutes, adding succinic anhydride, heating to 60-80° C., reacting for 1-2 hours, filtering, washing, and drying to obtain modified montmorillonite; Step B, dispersing the modified montmorillonite evenly in N,N-dimethylformamide solution, adding dextran and p-toluenesulfonic acid, stirring evenly, heating to 90-100° C., reacting for 1-2 hours, discharging, and obtaining a montmorillonite additive; The preparation method of the antibacterial additive is: Ⅰ: Add polycarbonate diol and epoxy POSS to n-octane solution, disperse evenly, add catalyst, heat to 60-80°C, react for 7-9h, separate, wash and dry to obtain substance A; II: Add substance A and the antibacterial agent to the N,N-dimethylformamide solution, stir evenly, add p-toluenesulfonic acid, heat to 50-60°C, react for 2-4h, wash, and dry to obtain the antibacterial additive; The antibacterial agent is guanidinopropionic acid or guanidinoacetic acid.

2. The polylactic acid composite fiber for diapers according to claim 1, characterized in that: In step A, the particle size of the montmorillonite is 3-5 μm.

3. The polylactic acid composite fiber for diapers according to claim 1, characterized in that: The lubricant is fatty alcohol polyoxyethylene ether or ethylene bisstearamide.

4. The polylactic acid composite fiber for diapers according to claim 1, characterized in that: In Ⅰ, the catalyst is tetrabutylammonium bromide or tetrabutylammonium chloride.

5. The polylactic acid composite fiber for diapers according to claim 1, characterized in that: The natural plant fiber is one or more of bamboo fiber, hemp fiber and straw fiber.

6. A method for preparing the polylactic acid composite fiber for diapers as claimed in claim 1, characterized in that: The following steps are involved: Step 1: Add polylactic acid, montmorillonite additive, antibacterial additive, lubricant, cellulose acetate, and natural plant fiber into a mixer and disperse them uniformly to obtain a mixture; Step 2: melt-blending, extruding and vacuum-drying the mixture through a twin-screw extruder and then spinning it on a melt spinning machine to obtain polylactic acid composite fibers.

7. The method for preparing polylactic acid composite fibers for diapers according to claim 6, characterized in that: The spinning temperature is 180-230° C., the winding speed is 1400-2000 m / min, the drawing temperature is 70-90° C., and the drawing multiple is 2.5-4.5 times.

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