Environment-friendly degradable wet tissue and preparation method thereof

Abstract

The invention discloses an environment-friendly degradable wet tissue and a preparation method thereof, and belongs to the technical field of wet tissues. Comprising a wet tissue base material and wet tissue immersion liquid. Wherein the wet tissue base material is prepared from the following raw materials in parts by mass: 67 to 83 parts of modified polylactic acid fiber, 37 to 49 parts of cotton fiber and 26 to 38 parts of wood pulp fiber. The wet tissue immersion liquid is prepared from the following raw materials in parts by mass: 80 to 100 parts of deionized water, 2 to 4 parts of glycerol, 1 to 3 parts of propylene glycol, 0.5 to 1.5 parts of hyaluronic acid and 0.3 to 0.5 part of preservative. The wet tissue base material endows the wet tissue with excellent degradability; modified polyethylene glycol is added into the modified polylactic acid fibers, so that the hydrophilicity of polylactic acid can be greatly enhanced, antibacterial groups are connected into molecules and can also play a synergistic role with polylactic acid, and the antibacterial property of the wet tissue is improved; in conclusion, the prepared wet tissue has hydrophilicity and antibacterial property, is environment-friendly and degradable, and has important application value in the technical field of wet tissues.

Description

Technical Field

[0001] The present invention belongs to the technical field of wet wipes, and specifically, relates to an environmentally friendly degradable wet wipe and a preparation method thereof. Background Art

[0002] A wet wipe is usually a kind of tissue paper made of pure water, spunlace non-woven fabric and propylene glycol, which is used for wiping the face, hands or skin. Among them, the spunlace non-woven fabric is a non-woven material that uses high-pressure water flow to puncture and entangle the fiber web to reinforce it into cloth. Due to its product characteristics, the preparation of non-woven fabric has the advantages of simple process, high production efficiency, low cost, wide use, diverse sources, etc., so it is widely used in many fields such as clothing lining, medical dressings, industrial filter linings, thermal insulation packaging, etc.

[0003] Traditional non-woven fabrics are made of synthetic fiber materials such as polyethylene, polypropylene, aramid, polyester, and natural fiber materials such as cotton and hemp. This results in the non-woven fabrics being difficult to degrade in the natural environment. This non-degradable characteristic makes it easy for non-woven fabrics to form garbage piles after being discarded. According to statistics, about 70% of the wet wipe waste generated globally each year eventually enters landfills or natural water bodies. These non-degradable materials can remain in the soil for hundreds of years, not only occupying a large amount of land resources, but also washing microplastic particles into the marine ecosystem through rainwater scouring, posing a threat to biodiversity.

[0004] With the development of microbial technology, there are already several biodegradable plastic varieties in the world, and the more and more popular one is polylactic acid. Polylactic acid is a polyester polymer obtained by polymerizing lactic acid as the main raw material. Its raw material is made from starch raw materials extracted from renewable plant resources. After use, it can be completely degraded by microorganisms in nature, and finally generate carbon dioxide and water. Its source and post-treatment are extremely environmentally friendly, and it is an ideal green polymer material. Therefore, various non-woven fabrics made of polylactic acid are biodegradable. However, polylactic acid has relatively strong lipophilicity, which is not conducive to improving water absorption and water retention as a disinfected wet wipe material; finally, although polylactic acid fibers have certain natural antibacterial properties, as a disinfected wet wipe, the antibacterial properties still need to be further enhanced. To sum up, there is an urgent need to invent an environmentally friendly degradable wet wipe with both water absorption and antibacterial properties to meet the higher requirements in the technical field of wet wipes. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide an environmentally friendly degradable wet wipe and a preparation method thereof.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] An environmentally friendly degradable wet wipe includes a wet wipe substrate and a wet wipe soaking solution.

[0008] Furthermore, the wet wipe substrate comprises raw materials in the following parts by mass: 67 - 83 parts of modified polylactic acid fiber, 37 - 49 parts of cotton fiber, and 26 - 38 parts of wood pulp fiber.

[0009] Furthermore, the wet wipe infusion comprises raw materials in the following parts by mass: 80 - 100 parts of deionized water, 2 - 4 parts of glycerol, 1 - 3 parts of propylene glycol, 0.5 - 1.5 parts of hyaluronic acid, and 0.3 - 0.5 parts of preservative.

[0010] Still further, the preservative is one of p - hydroxybenzoate, phenoxyethanol, and potassium sorbate.

[0011] Still further, the modified polylactic acid fiber is prepared through the following steps:

[0012] Step 1: Dry and mix PLLA polylactic acid, modified polyethylene glycol, talcum powder, and antioxidant to form a mixture.

[0013] Step 2: Add the mixture into a melt spinning device for melt spinning, and collect the as - spun fibers obtained.

[0014] Step 3: Perform hot drawing and heat setting on the as - spun fibers in sequence to obtain the modified polylactic acid fiber.

[0015] Still further, each raw material is as follows by parts by mass: 62 - 76 parts of PLLA polylactic acid, 12 - 18 parts of modified polyethylene glycol, 1 - 3 parts of talcum powder, and 3 - 6 parts of antioxidant.

[0016] Still further, the antioxidant is a hindered phenol antioxidant.

[0017] Still further, the temperature of the drying is 80 - 120 °C, and the time is 6 - 12 h.

[0018] Still further, the spinning temperature of the melt spinning is 180 - 220 °C, and the spinning speed is 300 - 400 m / min.

[0019] Adding a small amount of talcum powder to the modified polylactic acid fiber can enhance the mechanical properties of polylactic acid; adding a hindered phenol antioxidant can also improve the antioxidant performance of polylactic acid.

[0020] Still further, the modified polyethylene glycol is prepared through the following steps:

[0021] A1. Under the protection of nitrogen atmosphere, pyridine, polyethylene glycol and anhydrous toluene were successively added into a 500 mL three-necked flask containing a magnetic stirrer. After stirring evenly, the device was heated. When the temperature reached 70 °C, thionyl chloride was slowly added dropwise into the flask, and the reaction was carried out at a constant temperature for 5 h. During the reaction process, the solution changed from a colorless solution to a white emulsion. After the reaction was completed, the mixture was allowed to stand for liquid separation. The upper layer solution was directly filtered to remove pyridine chloride, and the upper layer filtrate was obtained. Then, the lower layer oily substance was washed with toluene, and after washing, it was mixed with the upper layer filtrate. Thionyl chloride and most of the toluene were removed by distillation using a rotary evaporator. After cooling and filtration, the remaining toluene was removed by distillation again to obtain chlorinated polyethylene glycol;

[0022] Under the catalysis of pyridine, excessive thionyl chloride reacts with polyethylene glycol; the reaction equation is as follows:

[0023]

[0024] A2. 5,5-Dimethylhydantoin, deionized water and sodium hydroxide were successively added into a 500 mL three-necked flask containing a magnetic stirrer. After continuous stirring until the solute was completely dissolved, chlorinated polyethylene glycol was added. The device was heated. When the temperature reached 50 °C, the reaction was carried out with constant stirring for 4 h. After the reaction was completed, the water in the reaction solution was removed by vacuum distillation using a rotary evaporator. The obtained solid was dissolved in absolute ethanol and filtered by suction to obtain an intermediate product;

[0025] Under the catalysis of sodium hydroxide, chlorinated polyethylene glycol and 5,5-dimethylhydantoin undergo a nucleophilic substitution reaction, and the molar ratio of their dosages is controlled at 2:1 (5,5-dimethylhydantoin is slightly in excess). The reaction equation is as follows:

[0026]

[0027] A3. The intermediate product, tert-butanol and deionized water were successively added into a 500 mL three-necked flask containing a magnetic stirrer. After stirring evenly, sodium hypochlorite was added into the three-necked flask. The device was placed in the dark and stirred at room temperature for 6 h. After the reaction was completed, the water was removed by vacuum distillation using a rotary evaporator and dried under vacuum to obtain modified polyethylene glycol;

[0028] Under the action of sodium hypochlorite, the N-H bond in the intermediate product molecule is transformed into an N-Cl bond to obtain modified polyethylene glycol.

[0029] Furthermore, in step A1, the dosage ratio of pyridine, polyethylene glycol, anhydrous toluene and thionyl chloride is 2.1 g:100 g:200 mL:29.7 g.

[0030] Further, the dosage ratio of 5,5-dimethylhydantoin, deionized water, sodium hydroxide, and chlorinated polyethylene glycol in step A2 is 26.7 g: 150 mL: 9.6 g: 102.1 g.

[0031] Further, the dosage ratio of the intermediate product, tert-butanol, deionized water, and sodium hypochlorite in step A3 is 121.7 g: 80 mL: 70 mL: 14.8 g.

[0032] The polyethylene glycol molecule contains a large number of ether bonds. Therefore, polyethylene glycol is a high-molecular compound with excellent hydrophilicity. Using it as a raw material to modify polylactic acid can significantly improve the hydrophilicity of polylactic acid. In addition, in the present invention, polyethylene glycol is modified to introduce chloramine groups on its molecular chain, releasing active halogens to destroy the cell membranes of microorganisms, inhibit enzyme activity, oxidize nucleic acids, and interfere with protein functions to achieve an efficient bactericidal effect. Moreover, it has a broad antibacterial spectrum and is relatively safe for the human body, greatly enhancing the antibacterial performance of polylactic acid. Finally, polyethylene glycol with a molecular weight of 1000 is selected in the present invention. It has a relatively large molecular weight and is not prone to migration in the polylactic acid matrix, and its performance is relatively stable.

[0033] A preparation method of an environmentally friendly and degradable wet wipe, comprising the following steps:

[0034] Lay the modified polylactic acid fiber, cotton fiber, and wood pulp fiber in layers in the order of the upper layer, middle layer, and lower layer to form a fiber web, then use the hydrospinning process to reinforce the fiber web to form a non-woven fabric, dry the non-woven fabric, and then wind it into a cloth roll through a winding device, cut it, add a wet wipe soaking solution, and perform sealed packaging to obtain an environmentally friendly and degradable wet wipe.

[0035] Advantages of the present invention:

[0036] 1. The wet wipe base material prepared in the present invention is a modified polylactic acid fiber, cotton fiber, and wood pulp fiber, endowing the wet wipe with excellent degradability and being environmentally friendly;

[0037] 2. By adding antioxidants, talcum powder, and modified polyethylene glycol to modify polylactic acid, the modified polyethylene glycol can significantly enhance the hydrophilicity of polylactic acid, and there are antibacterial groups connected to its molecules, and it can also play a synergistic role with polylactic acid to improve the antibacterial property of the wet wipe;

[0038] In summary, the wet wipe prepared in the present invention has both hydrophilicity and antibacterial properties, and is environmentally friendly and degradable, having important application value in the wet wipe technology field. Specific embodiments

[0039] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0040] Example 1

[0041] Preparation of modified polyethylene glycol:

[0042] A1. Under the protection of a nitrogen atmosphere, 2.1 g of pyridine, 100 g of polyethylene glycol, and 200 mL of anhydrous toluene were successively added to a 500 mL three-necked flask containing a magnetic stirrer. After stirring evenly, the device was heated. When the temperature reached 70 °C, 29.7 g of thionyl chloride was slowly added dropwise to the flask, and the reaction was carried out at a constant temperature for 5 h. During the reaction, the solution changed from a colorless solution to a white emulsion. After the reaction was completed, the mixture was allowed to stand and layer. The upper layer solution was directly filtered to remove pyridine chloride, and the upper layer filtrate was obtained. Then, the lower oily substance was washed with toluene, and after washing, it was mixed with the upper layer filtrate. Thionyl chloride and most of the toluene were removed by distillation using a rotary evaporator. After cooling and filtration, the remaining toluene was removed by distillation again to obtain chlorinated polyethylene glycol.

[0043] A2. 26.7 g of 5,5-dimethylhydantoin, 150 mL of deionized water, and 9.6 g of sodium hydroxide were successively added to a 500 mL three-necked flask containing a magnetic stirrer. After continuous stirring until the solute was completely dissolved, 102.1 g of chlorinated polyethylene glycol was added. The device was heated. When the temperature reached 50 °C, the reaction was carried out with constant stirring for 4 h. After the reaction was completed, the water in the reaction solution was removed by vacuum distillation using a rotary evaporator. The obtained solid was dissolved in absolute ethanol and filtered by suction to obtain an intermediate product.

[0044] A3. 121.7 g of the intermediate product, 80 mL of tert-butanol, and 70 mL of deionized water were successively added to a 500 mL three-necked flask containing a magnetic stirrer. After stirring evenly, 14.8 g of sodium hypochlorite was added to the three-necked flask. The device was placed in the dark and stirred at room temperature for 6 h. After the reaction was completed, the mixture was subjected to vacuum distillation using a rotary evaporator and vacuum dried to obtain modified polyethylene glycol.

[0045] Example 2

[0046] Preparation of modified polyethylene glycol:

[0047] A1. Under the protection of nitrogen atmosphere, 4.1 g of pyridine, 200 g of polyethylene glycol and 400 mL of anhydrous toluene were successively added to a 1000 mL three-necked flask containing a magnetic stirrer. After stirring evenly, the device was heated. When the temperature reached 70 °C, 59.4 g of thionyl chloride was slowly added dropwise to the flask, and the reaction was carried out at a constant temperature for 5 h. During the reaction, the solution changed from a colorless solution to a white emulsion. After the reaction was completed, the mixture was allowed to stand for layer separation. The upper layer solution was directly filtered to remove pyridine chloride, and the upper layer filtrate was obtained. Then, the lower layer oily substance was washed with toluene, and after washing, it was mixed with the upper layer filtrate. Thionyl chloride and most of the toluene were removed by distillation using a rotary evaporator. After cooling and filtration, the remaining toluene was removed by distillation again to obtain chlorinated polyethylene glycol;

[0048] A2. 53.4 g of 5,5-dimethylhydantoin, 300 mL of deionized water and 19.2 g of sodium hydroxide were successively added to a 1000 mL three-necked flask containing a magnetic stirrer. After continuous stirring until the solute was completely dissolved, 204.2 g of chlorinated polyethylene glycol was added. The device was heated. When the temperature reached 50 °C, the reaction was stirred at a constant temperature for 4 h. After the reaction was completed, the water in the reaction solution was removed by vacuum distillation using a rotary evaporator. The obtained solid was dissolved in absolute ethanol and filtered by suction to obtain an intermediate product;

[0049] A3. 243.4 g of the intermediate product, 160 mL of tert-butanol and 140 mL of deionized water were successively added to a 1000 mL three-necked flask containing a magnetic stirrer. After stirring evenly, 29.6 g of sodium hypochlorite was added to the three-necked flask. The device was placed in the dark and stirred at room temperature for 6 h. After the reaction was completed, vacuum distillation was carried out using a rotary evaporator, and vacuum drying was carried out to obtain modified polyethylene glycol.

[0050] Example Three

[0051] Preparation of modified polylactic acid fiber:

[0052] Step 1. 62 g of PLLA polylactic acid (molecular weight 1000), 12 g of the modified polyethylene glycol prepared in Example One, 1 g of talc powder and 3 g of antioxidant 1010 were dried at 80 °C for 6 h and then mixed to form a mixture;

[0053] Step 2. The mixture was added to a melt spinning device, and melt spinning was carried out at a temperature of 180 °C and a spinning speed of 300 m / min, and the obtained as-spun fiber was collected;

[0054] Step 3. The as-spun fiber was successively subjected to hot drawing and heat setting to obtain modified polylactic acid fiber.

[0055] Example Four

[0056] Preparation of modified polylactic acid fiber:

[0057] Step 1: Mix 76 g of PLLA polylactic acid (molecular weight 1000), 18 g of the modified polyethylene glycol prepared in Example 2, 3 g of talcum powder, and 6 g of antioxidant 1010 after drying at 120°C for 12 h to form a mixture.

[0058] Step 2: Add the mixture into a melt spinning device, and perform melt spinning at a temperature of 220°C and a spinning speed of 400 m / min, and collect the as-spun fibers obtained.

[0059] Step 3: Perform hot drawing and heat setting on the as-spun fibers in sequence to obtain the modified polylactic acid fibers.

[0060] Example 5

[0061] Lay 67 g of the modified polylactic acid fibers prepared in Example 3, 37 g of cotton fibers, and 26 g of wood pulp fibers in layers in the order of upper layer, middle layer, and lower layer to form a fiber web, and then reinforce the fiber web by a hydroentangling process to obtain a non-woven fabric.

[0062] Example 6

[0063] Lay 75 g of the modified polylactic acid fibers prepared in Example 4, 43 g of cotton fibers, and 32 g of wood pulp fibers in layers in the order of upper layer, middle layer, and lower layer to form a fiber web, and then reinforce the fiber web by a hydroentangling process to obtain a non-woven fabric.

[0064] Example 7

[0065] Lay 83 g of the modified polylactic acid fibers prepared in Example 4, 49 g of cotton fibers, and 38 g of wood pulp fibers in layers in the order of upper layer, middle layer, and lower layer to form a fiber web, and then reinforce the fiber web by a hydroentangling process to obtain a non-woven fabric.

[0066] Example 8

[0067] Lay 67 g of the modified polylactic acid fibers prepared in Example 3, 37 g of cotton fibers, and 26 g of wood pulp fibers in layers in the order of upper layer, middle layer, and lower layer to form a fiber web, and then reinforce the fiber web by a hydroentangling process to obtain a non-woven fabric; dry the non-woven fabric, then wind it into a cloth roll through a winding device, slit it, and then add a wet wipe soaking solution and perform sealed packaging to obtain an environmentally friendly degradable wet wipe;

[0068] Among them, the wet wipe soaking solution is prepared by uniformly mixing 80 g of deionized water, 2 g of glycerol, 1 g of propylene glycol, 0.5 g of hyaluronic acid, and 0.3 g of p-hydroxybenzoate.

[0069] Example 9

[0070] 83 g of the modified polylactic acid fibers prepared in Example 4, 49 g of cotton fibers and 38 g of wood pulp fibers were laid in layers in the order of upper layer, middle layer and lower layer to form a fiber web, and then the fiber web was reinforced by a hydroentangling process to obtain a non-woven fabric; the non-woven fabric was dried, wound into a cloth roll by a winding device, slit, and then added with a wet wipe soaking solution and sealed and packaged to obtain an environmentally friendly degradable wet wipe;

[0071] Among them, the wet wipe soaking solution was prepared by uniformly mixing 100 g of deionized water, 4 g of glycerol, 3 g of propylene glycol, 1.5 g of hyaluronic acid, and 0.5 g of potassium sorbate.

[0072] Comparative Example 1

[0073] In the preparation process of Example 7, only the modified polylactic acid fibers were replaced with an equal amount of ordinary polylactic acid fibers, and the other conditions remained unchanged to obtain a non-woven fabric.

[0074] Comparative Example 2

[0075] Commercially available polylactic acid non-woven fabric was used.

[0076] Examples 5, 6, 7 and Comparative Examples 1 and 2 were subjected to the following performance tests:

[0077] The national standard GB / T 20944.3-2008 was adopted to measure the antibacterial rates of Streptococcus mutans and Staphylococcus aureus;

[0078] The national standard GB / T 24218-2017 was adopted to measure the water absorption ratio;

[0079] The standard ISO14855:1999 was adopted to measure compost degradation;

[0080] The measured results are shown in the following table:

[0081]

[0082] As can be seen from the above table, the non-woven fabric prepared in the embodiment of the present invention has higher hydrophilicity and antibacterial properties than the comparative examples, and has degradability. Using it as a raw material for wet wipes can improve the hydrophilicity and antibacterial properties of wet wipes. Therefore, the present invention has important application value in the technical field of wet wipes.

[0083] In the description of the specification, the descriptions referring to the terms "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0084] The above content is only an example and illustration of the present invention. Those skilled in the art to which the present technology pertains may make various modifications or supplements to the described specific embodiments or use similar methods for substitution, and all should fall within the protection scope of the present invention.

Claims

1. An environmentally friendly and degradable wet wipe, comprising a wet wipe substrate and a wet wipe infusion, characterized in that, The wet wipe substrate comprises raw materials in the following parts by mass: 67 - 83 parts of modified polylactic acid fiber, 37 - 49 parts of cotton fiber, and 26 - 38 parts of wood pulp fiber.

2. The environmentally friendly and degradable wet wipes according to claim 1, characterized in that, The modified polylactic acid fiber is prepared by melt spinning from raw materials in the following parts by mass: 62 - 76 parts of PLLA polylactic acid, 12 - 18 parts of modified polyethylene glycol, 1 - 3 parts of talcum powder, and 3 - 6 parts of antioxidant.

3. The environmentally friendly and degradable wet wipes according to claim 2, characterized in that, The modified polyethylene glycol is prepared through the following steps: A1. Under nitrogen protection, pyridine, polyethylene glycol, and anhydrous toluene are sequentially added into a flask. After stirring evenly, it is heated to 70°C, and then thionyl chloride is added dropwise. The reaction is carried out at a constant temperature for 5 h. After the reaction is completed, chlorinated polyethylene glycol is obtained. A2. 5,5 - dimethylhydantoin, deionized water, and sodium hydroxide are sequentially added into the flask. After stirring until the solute is dissolved, chlorinated polyethylene glycol is added. When it is heated to 50°C, the reaction is stirred at a constant temperature for 4 h. After the reaction is completed, an intermediate product is obtained. A3. The intermediate product, tert - butyl alcohol, and deionized water are sequentially added into the flask. After stirring evenly, sodium hypochlorite is added into the flask. Under dark conditions, the reaction is stirred at room temperature for 6 h. After the reaction is completed, modified polyethylene glycol is obtained.

4. The environmentally friendly and degradable wet wipe according to claim 3, characterized in that, In step A1, the dosage ratio of pyridine, polyethylene glycol, anhydrous toluene, and thionyl chloride is 2.1 g:100 g:200 mL:29.7 g.

5. The environmentally friendly and degradable wet wipe according to claim 3, characterized in that, In step A2, the dosage ratio of 5,5 - dimethylhydantoin, deionized water, sodium hydroxide, and chlorinated polyethylene glycol is 26.7 g:150 mL:9.6 g:102.1 g.

6. An environmentally friendly degradable wet wipe according to claim 3, characterized in that, In step A3, the dosage ratio of the intermediate product, tert - butyl alcohol, deionized water, and sodium hypochlorite is 121.7 g:80 mL:70 mL:14.8 g.

7. An environmentally friendly and degradable wet wipe according to claim 1, characterized in that, The wet wipe infusion comprises raw materials in the following parts by mass: 80 - 100 parts of deionized water, 2 - 4 parts of glycerol, 1 - 3 parts of propylene glycol, 0.5 - 1.5 parts of hyaluronic acid, and 0.3 - 0.5 parts of preservative.

8. The environmentally friendly and degradable wet wipe according to claim 7, characterized in that, The preservative is one of p - hydroxybenzoate, phenoxyethanol, and potassium sorbate.

9. The preparation method of an environmentally friendly degradable wet wipe according to any one of claims 1-8, characterized in that , including the following steps: The modified polylactic acid fiber, cotton fiber, and wood pulp fiber are laid in layers in the order of upper layer, middle layer, and lower layer to form a fiber web. Then, through a hydro - entanglement process, a non - woven fabric is formed. The non - woven fabric is dried, wound, slit, and then the wet wipe infusion is added for packaging to obtain an environmentally friendly and degradable wet wipe.

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