Wet tissue liquid spraying equipment and method for wet tissue production

Abstract

The invention discloses a wet tissue liquid spraying device and method for wet tissue production, and relates to the field of liquid phase treatment of textile materials.The method comprises the following steps that S1, wet tissue liquid is sprayed to the surface of a wet tissue base material at the pressure of 0.15-0.25 MPa; s2, spraying the residual wet tissue liquid to the surface of the pre-wetted wet tissue base material at the pressure of 0.6-0.8 MPa; and S3, during the period of pre-wetting spraying and post-high-pressure spraying, gas is sprayed to the edge of the wet tissue base material, and edge gas curtain constraint liquid drops are formed. Through the composite process of staged spraying and air curtain constraint, low-pressure pre-spraying mildly wets the surface of a base material, high-pressure post-spraying drives liquid molecules to penetrate into the base material by means of guiding of a pre-wetting channel, meanwhile, air curtain constraint effectively prevents liquid drops from flying and escaping, the spraying efficiency and the liquid utilization rate are further improved, and the spraying effect is improved. Therefore, the foaming rate is obviously reduced, the liquid utilization rate is improved, the distribution uniformity of the liquid on the wet tissue base material is ensured, and the use effect of the wet tissue is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid-phase treatment of textile materials, particularly to spraying or jetting, and specifically to a wet wipe liquid spraying device and method for wet wipe production. Background Art

[0002] With the increasing global environmental awareness, the application of degradable materials in the field of personal hygiene products is becoming more and more extensive, especially environmentally friendly wet wipes based on natural materials such as bamboo fiber and cotton fiber. Such degradable wet wipes can not only reduce plastic pollution, but also be favored by consumers due to their natural skin-friendly characteristics. However, the performance of environmentally friendly degradable wet wipes highly depends on the uniform distribution and effective penetration of the wet wipe liquid, and the formula of the wet wipe liquid is gradually transforming towards naturalization, for example, using plant extracts such as saponins and polysaccharides as surface active ingredients. Although such natural ingredients are environmentally friendly and safe, their physical properties (such as large viscosity fluctuations, easy foaming, and complex interfacial activity) pose higher requirements for the spraying process.

[0003] Traditional wet wipe liquid spraying mostly relies on high-pressure jetting to achieve rapid coverage through high-speed liquid flow. However, the surface active substances in the natural ingredient wet wipe liquid are prone to generate foam under high shear force, and when the high-viscosity liquid penetrates into the degradable substrate with complex pores, the interfacial tension easily causes the liquid to accumulate on the fiber surface, forming local dry areas or bubble retention. The presence of bubbles not only reduces the liquid utilization rate, but also affects the cleaning effect and touch of the wet wipes.

[0004] Therefore, it is necessary to improve the deficiencies in the prior art to solve the above problems. Summary of the Invention

[0005] The present invention overcomes the deficiencies of the prior art and provides a wet wipe liquid spraying device and method for wet wipe production. Through innovative processes and equipment, uniform spraying of the wet wipe liquid is achieved, the liquid utilization rate is increased, and the production cost is reduced, thereby meeting the market demand for high-quality and environmentally friendly wet wipes.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a wet wipe liquid spraying method for wet wipe production, the spraying method is applicable to the spraying operation of degradable environmentally friendly wet wipes containing natural ingredient wet wipe liquid, and the spraying method includes the following steps: S1. Spray the wet wipe liquid onto the surface of the wet wipe substrate at a pressure of 0.15 - 0.25 MPa to achieve pre-wetting spraying; S2. After a certain time interval after the low-pressure pre-spraying, spray the remaining total amount of the wet wipe liquid onto the pre-wetted wet wipe substrate at a pressure of 0.6 - 0.8 MPa to achieve post-high-pressure spraying; S3. During the pre-wetting spraying and post-high-pressure spraying, spray gas onto the edges of the wet wipe substrate to form an edge air curtain to restrain the liquid droplets.

[0007] In a preferred embodiment of the present invention, the natural ingredient wet wipe solution contains saponin or polysaccharide components and has a viscosity of 50-200 mPa·s; the substrate of the degradable and environmentally friendly wet wipe is one of bamboo fiber, cotton fiber or non-woven fabric, and the porosity of the substrate is 30-70%.

[0008] In a preferred embodiment of the present invention, in the step of S1, the duration of the pre-wetting spray is 1-2 s, the droplet size is 80-120 μm, and the spraying amount is 15-30% of the total spraying amount.

[0009] In a preferred embodiment of the present invention, the spraying distances of the pre-wetting spray and the post-high-pressure spray relative to the wet wipe substrate are 10-15 cm, and the spraying interval time between the two is 3-6 s.

[0010] In a preferred embodiment of the present invention, in the step of S2, the duration of the post-high-pressure spray is 3-4 s, the droplet size is 20-50 μm, and the spraying amount is 70-85% of the total spraying amount.

[0011] In a preferred embodiment of the present invention, in the step of S3, the jet angle of the gas from the outside to the edge direction of the wet wipe substrate is 15-30°, the air flow pressure is 0.05-0.1 MPa, the air flow velocity is 5-8 m / s, and the distance between the edge of the edge air curtain and the edge of the wet wipe substrate is 0-13 mm.

[0012] The present invention provides a spraying device for a wet wipe solution spraying method for wet wipe production, including: an equipment frame, a plurality of conveying rollers rotatably connected to the top of the equipment frame, and two spraying boxes fixedly segmented on the top of the equipment frame; Spraying mechanisms and jetting mechanisms are arranged inside both of the two spraying boxes. The spraying mechanisms are used to respectively perform pre-wetting spraying and post-high-pressure spraying on the wet wipe substrate, and the jetting mechanisms are used to realize droplet constraint at the edge of the wet wipe substrate during pre-wetting spraying and post-high-pressure spraying; a power mechanism for driving the plurality of conveying rollers to rotate synchronously is installed on the equipment frame.

[0013] In a preferred embodiment of the present invention, the spraying mechanism includes: a plurality of mounting plates fixed inside the spraying box, a plurality of spray heads mounted on the mounting plates, and an infusion pipe fixed on the tops of the plurality of spray heads; an infusion head for externally connecting an infusion device to supply the wet wipe solution is installed on the top of the infusion pipe.

[0014] In a preferred embodiment of the present invention, the jetting mechanism includes: a plurality of mounting rods fixed inside the spraying box, a plurality of connecting rods disposed at the bottom of the mounting rods, and a plurality of jetting heads disposed on one side of the plurality of connecting rods; a gas delivery head for externally connecting a gas delivery device to achieve gas supply is installed at the top end of the jetting head, and both ends of the connecting rod are respectively connected to the mounting rod and the jetting head through pipe clamps for adjusting the jetting direction of the jetting head.

[0015] In a preferred embodiment of the present invention, a limiting plate for preventing deviation during the conveyance of the wet wipe substrate is fixed to the side of the spraying box, and conical frames for recovering the wet wipe liquid are installed at the bottoms of both the equipment frame and the spraying box, and a recovery pipe is fixed to the bottom of the conical frame.

[0016] The present invention solves the defects existing in the background art and has the following beneficial effects: (1) The present invention provides a wet wipe liquid spraying device and method for wet wipe production. Through the composite process of staged spraying and air curtain constraint, the spraying process of degradable wet wipes is comprehensively optimized. By using low-pressure pre-spraying, the surface of the substrate is gently wetted to form a continuous liquid film, reducing the interfacial tension between the fiber and the liquid, reducing the bubble nuclei generated when the high-viscosity liquid contacts the pore structure, and through high-pressure post-spraying, with the guidance of the pre-wetting channel, driving the liquid molecules to penetrate deep into the substrate, and avoiding the direct impact of high pressure on the non-wetted area resulting in gas retention. At the same time, the air curtain constraint effectively prevents the scattering and escape of liquid droplets, further improving the spraying efficiency and liquid utilization rate, thereby significantly reducing the foaming rate, increasing the liquid utilization rate, and ensuring the uniform distribution of the liquid on the wet wipe substrate, thus greatly enhancing the use effect of the wet wipes.

[0017] (2) In the present invention, by adopting low-pressure pre-spraying, the kinetic energy of the liquid droplets is relatively low, and the surfactant molecules in the wet wipe liquid can be orderly arranged on the fiber surface to form a stable liquid film through hydrogen bonds and van der Waals forces, reducing the interfacial energy between the liquid and the fiber, promoting capillary penetration, and using the conductive effect of the polar molecules in the wetting liquid film to neutralize the surface charge of the substrate, eliminating electrostatic repulsion, and preventing the liquid droplets from scattering due to electrostatic repulsion during subsequent spraying, thereby providing a basis for uniform liquid distribution and ensuring the uniform coverage effect of the wet wipe liquid on the substrate.

[0018] (3) In the present invention, by adopting high-pressure post-spraying on the basis of pre-wetting, using kinetic energy conversion, it can drive the liquid to penetrate deep into the substrate along the pre-wetting channel, achieving deeper penetration, thereby improving the uniformity of liquid distribution. At the same time, since the pre-wetting liquid film has occupied the pores of the substrate, the residual gas is compressed and discharged, which can avoid the formation of bubble residues due to gas compression under high pressure, thereby further improving the quality and use effect of the wet wipes.

[0019] (4) In the present invention, during the spraying process, an edge air curtain formed by injecting gas is used to constrain the droplet trajectory by means of hydrodynamic effects. The Coanda effect generated causes the air flow to flow along the curved surface of the substrate edge. The escaping droplets are affected by the shear force of the air curtain and change their movement direction, so that they are re-adsorbed into the spraying area. Furthermore, the directional guidance of the air flow to the droplets enhances the contact probability between the liquid and the fibers, improves the effective utilization rate of the intermolecular force, not only reduces liquid waste, but also ensures uniform wetting in the edge area, thereby improving the moisture retention performance and cleaning effect of the wet wipes. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. Figure 1 It is a three-dimensional structural diagram of the spraying device according to the preferred embodiment of the present invention. Figure 2 It is a front half-sectional view structural diagram of the spraying box according to the preferred embodiment of the present invention. Figure 3 It is a side half-sectional view structural diagram of the spraying box according to the preferred embodiment of the present invention. In the figure: 1, equipment frame; 2, conveying roller; 3, spraying box; 31, mounting plate; 311, spraying head; 312, infusion pipe; 313, infusion head; 32, mounting rod; 321, connecting rod; 322, air jet head; 323, air delivery head; 4, limiting plate; 5, conical frame; 51, recovery pipe. Specific Embodiments

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all 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.

[0022] Many specific details are set forth in the following description in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0023] In the description of this application, it should be understood that the orientation or positional relationship indicated by "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of this application. In addition, in the description of this invention, unless otherwise specified, the meaning of "several" is two or more.

[0024] In the description of this application, it should be noted that unless otherwise clearly specified and defined, the terms "install", "connect", and "couple" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood through specific circumstances.

[0025] It should be noted that the raw materials, equipment, reagents, etc. used in this invention can all be obtained through market purchase or by means of preparation in the prior art.

[0026] A wet wipe liquid spraying method for wet wipe production, the spraying method is applicable to the spraying operation of degradable and environmentally friendly wet wipes containing natural ingredient wet wipe liquid. The spraying method includes the following steps: S1. Spray the wet wipe liquid onto the surface of the wet wipe substrate at a pressure of 0.15 - 0.25 MPa to achieve pre-wetting spraying; S2. After a certain time interval after the low-pressure pre-spraying, spray the remaining total amount of the wet wipe liquid onto the pre-wetted wet wipe substrate at a pressure of 0.6 - 0.8 MPa to achieve post-high-pressure spraying; S3. During the pre-wetting spraying and the post-high-pressure spraying, jet gas towards the edge of the wet wipe substrate to form an edge air curtain to confine the droplets.

[0027] In some specific embodiments, the natural ingredient wet wipe liquid contains saponin or polysaccharide components, and the viscosity is 50 - 200 mPa·s; the substrate of the degradable and environmentally friendly wet wipe is one of bamboo fiber, cotton fiber or non-woven fabric, and the porosity of the substrate is 30 - 70%.

[0028] In some specific embodiments, in the step of S1, the duration of the pre-wetting spraying is 1 - 2 s, the droplet diameter is 80 - 120 μm, and the spraying amount is 15 - 30% of the total spraying amount.

[0029] In some specific embodiments, the spraying distances of the pre-wetting spraying and the post-high-pressure spraying with respect to the wet wipe substrate are 10 - 15 cm, and the spraying interval time between the two is 3 - 6 s.

[0030] In some specific embodiments, in the step of S2, the duration of the post-high-pressure spraying is 3 - 4 s, the droplet size is 20 - 50 μm, and the spraying amount is 70 - 85% of the total spraying amount.

[0031] In some specific embodiments, in the step of S3, the jetting angle of the gas from the outside to the edge direction of the wet wipe substrate is 15 - 30°, the air flow pressure is 0.05 - 0.1 MPa, the air flow velocity is 5 - 8 m / s, and the distance between the edge of the edge air curtain and the edge of the wet wipe substrate is 0 - 13 mm.

[0032] To further make the object and effect of the present invention simple and easy to understand, the present invention is further elaborated in combination with examples and comparative examples.

[0033] It should be noted that in the examples and comparative examples, the wet wipe substrate and the wet wipe liquid are described as follows: Wet wipe substrate: Bamboo fiber non-woven fabric, porosity 47%, gram weight 60 g / m², thickness 1.8 mm, initial humidity: 3.45 kg of water content per 100 kg of substrate; Wet wipe liquid: It includes the following preparation raw materials: saponin extract (purity ≥ 95%) with a mass ratio of 5%, seaweed polysaccharide (molecular weight 10 - 50 kDa) with a mass ratio of 3%, glycerol with a mass ratio of 2%, water with a mass ratio of 89.8%, and phenoxyethanol with a mass ratio of 0.2%; It includes the following preparation steps: 1. Heat the water to 40 °C, stir at 200 rpm, slowly add the saponin extract, and continuously stir for 30 min until completely dissolved to form a transparent solution; 2. Then add the seaweed polysaccharide, raise the temperature to 50 °C, and stir for 1 h until the polysaccharide is fully swollen and evenly dispersed; 3. Cool down to below 30 °C, add glycerol and phenoxyethanol in sequence, and stir for 15 min to mix evenly; 4. Pass through a 200-mesh filter screen, let it stand to defoam, and obtain a wet wipe liquid with a viscosity of 120 mPa·s.

[0034] Example 1

[0035] A method for spraying a wet wipe liquid for wet wipe production includes the following steps: S1. Spray 3 kg of the wet wipe liquid onto the surface of the wet wipe substrate at a pressure of 0.2 MPa, a droplet size of 100 μm, and a duration of 1.5 s to achieve pre-wetting spraying; S2. After a 5-s interval following low-pressure pre-spraying, spray 7 kg of wet wipe liquid onto the pre-wetted wet wipe substrate surface at a pressure of 0.7 MPa with a droplet size of 40 μm for 3.5 s to achieve post-high-pressure spraying. S3. During pre-wetting spraying and post-high-pressure spraying, eject gas at a jet angle of 20°, an air flow pressure of 0.08 MPa, and an air flow velocity of 6 m / s towards the edge of the wet wipe substrate to form an edge air curtain to confine the droplets, and keep the distance between the edge of the edge air curtain and the edge of the wet wipe substrate at 5 mm.

[0036] Among them, the spraying distances of the pre-wetting spraying and the post-high-pressure spraying with respect to the wet wipe substrate are 12 cm.

[0037] Example 2

[0038] This example is basically the same as Example 1, the difference is that: the specific steps of S2 are: after a 3-s interval following low-pressure pre-spraying, spray 7 kg of wet wipe liquid onto the pre-wetted wet wipe substrate surface at a pressure of 0.7 MPa with a droplet size of 40 μm for 3.5 s to achieve post-high-pressure spraying.

[0039] Example 3

[0040] This example is basically the same as Example 1, the difference is that: the specific steps of S2 are: after a 6-s interval following low-pressure pre-spraying, spray 7 kg of wet wipe liquid onto the pre-wetted wet wipe substrate surface at a pressure of 0.7 MPa with a droplet size of 40 μm for 3.5 s to achieve post-high-pressure spraying.

[0041] Example 4

[0042] This example is basically the same as Example 1, the difference is that: the specific steps of S3 are: during pre-wetting spraying and post-high-pressure spraying, eject gas at a jet angle of 15°, an air flow pressure of 0.08 MPa, and an air flow velocity of 6 m / s towards the edge of the wet wipe substrate to form an edge air curtain to confine the droplets, and keep the distance between the edge of the edge air curtain and the edge of the wet wipe substrate at 5 mm.

[0043] Example 5

[0044] This example is basically the same as Example 1, the difference is that: the specific steps of S3 are: during pre-wetting spraying and post-high-pressure spraying, eject gas at a jet angle of 30°, an air flow pressure of 0.08 MPa, and an air flow velocity of 6 m / s towards the edge of the wet wipe substrate to form an edge air curtain to confine the droplets, and keep the distance between the edge of the edge air curtain and the edge of the wet wipe substrate at 5 mm.

[0045] Example 6

[0046] This embodiment is basically the same as Embodiment 1, except that: The steps of S3 are specifically as follows: During pre-wetting spraying and post-high-pressure spraying, gas is sprayed at a jet angle of 20°, a gas flow pressure of 0.08 MPa, and a gas flow velocity of 6 m / s towards the edge of the wet wipe substrate to form an edge air curtain to restrain droplets, and the edge of the edge air curtain is kept coincident with the edge of the wet wipe substrate.

[0047] Embodiment 7

[0048] This embodiment is basically the same as Embodiment 1, except that: The steps of S3 are specifically as follows: During pre-wetting spraying and post-high-pressure spraying, gas is sprayed at a jet angle of 20°, a gas flow pressure of 0.08 MPa, and a gas flow velocity of 6 m / s towards the edge of the wet wipe substrate to form an edge air curtain to restrain droplets, and the distance between the edge of the edge air curtain and the edge of the wet wipe substrate is kept at 13 mm.

[0049] Comparative Example 1 A method for spraying wet wipe liquid in wet wipe production includes the following steps: S1. Spray 10 kg of wet wipe liquid onto the surface of the pre-wetted wet wipe substrate at a pressure of 0.7 MPa, with a droplet size of 40 μm, for 3.5 s to achieve high-pressure spraying; S2. During high-pressure spraying, gas is sprayed at a jet angle of 20°, a gas flow pressure of 0.08 MPa, and a gas flow velocity of 6 m / s towards the edge of the wet wipe substrate to form an edge air curtain to restrain droplets, and the distance between the edge of the edge air curtain and the edge of the wet wipe substrate is kept at 5 mm.

[0050] Comparative Example 2 A method for spraying wet wipe liquid in wet wipe production includes the following steps: S1. Spray 7 kg of wet wipe liquid onto the surface of the wet wipe substrate at a pressure of 0.7 MPa, with a droplet size of 40 μm, for 3.5 s to achieve pre-high-pressure spraying; S2. After a 5-s interval from pre-high-pressure spraying, spray 3 kg of wet wipe liquid onto the surface of the wet wipe substrate at a pressure of 0.2 MPa, with a droplet size of 100 μm, for 1.5 s to achieve post-low-pressure spraying; S3. During pre-high-pressure spraying and post-low-pressure spraying, gas is sprayed at a jet angle of 20°, a gas flow pressure of 0.08 MPa, and a gas flow velocity of 6 m / s towards the edge of the wet wipe substrate to form an edge air curtain to restrain droplets, and the distance between the edge of the edge air curtain and the edge of the wet wipe substrate is kept at 5 mm.

[0051] Comparative Example 3 This comparative example is basically the same as Example 1, the difference being that: the steps of S2 are specifically as follows: after low-pressure pre-spraying, with an interval of 1.5 s, then 7 kg of wet wipe liquid is sprayed onto the pre-wetted wet wipe substrate surface at a pressure of 0.7 MPa and a droplet size of 40 μm for 3.5 s to achieve post-high-pressure spraying.

[0052] Comparative Example 4 This comparative example is basically the same as Example 1, the difference being that: the steps of S2 are specifically as follows: after low-pressure pre-spraying, with an interval of 7 s, then 7 kg of wet wipe liquid is sprayed onto the pre-wetted wet wipe substrate surface at a pressure of 0.7 MPa and a droplet size of 40 μm for 3.5 s to achieve post-high-pressure spraying.

[0053] Comparative Example 5 This comparative example is basically the same as Example 1, the difference being that: there is no edge air curtain constraint in step S3.

[0054] Comparative Example 6 This comparative example is basically the same as Example 1, the difference being that: the steps of S3 are specifically as follows: during pre-wetting spraying and post-high-pressure spraying, gas is sprayed onto the edge of the wet wipe substrate at a vertical jet angle, an air flow pressure of 0.08 MPa, and an air flow speed of 6 m / s to form an edge air curtain to constrain droplets, and the distance between the edge of the edge air curtain and the edge of the wet wipe substrate is maintained at 5 mm.

[0055] Comparative Example 7 This comparative example is basically the same as Example 1, the difference being that: the steps of S3 are specifically as follows: during pre-wetting spraying and post-high-pressure spraying, gas is sprayed onto the edge of the wet wipe substrate at a jet angle of 35°, an air flow pressure of 0.08 MPa, and an air flow speed of 6 m / s to form an edge air curtain to constrain droplets, and the distance between the edge of the edge air curtain and the edge of the wet wipe substrate is maintained at 5 mm.

[0056] Comparative Example 8 This comparative example is basically the same as Example 1, the difference being that: the steps of S3 are specifically as follows: during pre-wetting spraying and post-high-pressure spraying, gas is sprayed onto the edge of the wet wipe substrate at a jet angle of 20°, an air flow pressure of 0.08 MPa, and an air flow speed of 6 m / s to form an edge air curtain to constrain droplets, and the distance between the edge of the edge air curtain and the edge of the wet wipe substrate is maintained at 15 mm.

[0057] Performance detection: The wet wipes after spraying wet wipe liquid in Examples 1-7 and Comparative Examples 1-8 were successively subjected to performance tests on the uniformity of wet wipe liquid distribution, foaming rate, and wet wipe liquid utilization rate, and the results are shown in Table 1.

[0058] Wet wipe liquid distribution uniformity: Referring to the test method for liquid content in Article 6.3 of the standard GB / T 27728-2011 "Wet Wipes", take 5 wet wipes, cut them into 9 zones, calculate the liquid volume difference in each zone by the weighing method, and evaluate with the CV value.

[0059] Foaming rate: The sprayed wet wipe is cut into 10 cm in size, weigh and record , cut the wet wipe into pieces and put them into a 50 mL centrifuge tube, add 40 mL of water, seal and let stand for 5 min, centrifuge at 2000 rpm for 5 min to break and float the bubbles in the wet wipe, carefully pour out the supernatant, collect the wet wipe fragments and liquid remaining at the bottom of the tube, transfer the residue to a filter paper of known mass, dry the surface moisture and then weigh , calculate the liquid mass in the wet wipe: , According to the liquid density , calculate the actual liquid volume: , Total pore volume of wet wipe Pre-determined by mercury intrusion method, bubble volume: , , convert the unit to mL / 100g wet wipe to measure the foaming rate.

[0060] Utilization rate of wet wipe liquid: .

[0061] Table 1: Performance test results of Examples 1-7 and Comparative Examples 1-8

[0062] As shown in Table 1: By comparing Example 1 with Comparative Example 1, it can be known that: when directly impacting the un-wetted substrate by single high-pressure spraying, the interfacial tension between the liquid and the fiber is not destroyed, the surfactant molecules cannot be arranged orderly, and the liquid is difficult to penetrate evenly. Furthermore, when high-pressure impacts the un-wetted area, the residual gas is compressed to form bubble nuclei, and electrostatic repulsion causes the liquid droplets to scatter. Although there is an air curtain constraint, the problems of uneven liquid distribution and bubble residue cannot be solved.

[0063] It can be known from the comparison between Example 1 and Comparative Example 2 that when the high-pressure liquid flow directly impacts the drying substrate first, the kinetic energy of the surfactant molecules is too high to form a stable liquid film, resulting in the aggregation of liquid on the surface layer and insufficient deep penetration. The subsequent low-pressure spraying cannot effectively drive the liquid deep into the pores, but instead exacerbates the droplet scattering, reducing the air curtain constraint efficiency. As a result, the distribution uniformity (CV value of 14.3 %), the foaming rate (12.5 mL / 100g), and the utilization rate (72.1%) are all much lower than those of Example 1.

[0064] It can be known from the comparison between Examples 1-3 and Comparative Examples 3 and 4 that when the interval time after pre-spraying is too short and post-high-pressure spraying is carried out directly, the pre-wetting liquid film is not fully stabilized, the residual gas is not completely discharged, and the bubbles are compressed and retained during the high-pressure post-spraying, resulting in an increase in the foaming rate (8.3 mL / 100g). Moreover, when the interval time is too long, the pre-wetting liquid film is partially dried, and the secondary interfacial tension is locally formed, hindering the liquid penetration, thus making it difficult to maintain the performance.

[0065] It can be known from the comparison between Example 1 and Comparative Example 5 that when there is no air curtain constraint, the droplets scatter to non-target areas due to impacts and air flow disturbances, etc., resulting in insufficient edge wetting and a decrease in the liquid utilization rate. At the same time, the scattered droplets volatilize in the air, leading to unstable composition and exacerbating bubble formation.

[0066] It can be known from the comparison between Examples 1, 4, and 5 and Comparative Examples 6 and 7 that when there is no air curtain constraint, for the edge air curtain formed by the vertical jetting angle, the air flow conflicts with the droplet movement direction, easily causing the escaped droplets not to be adsorbed back into the spraying area, resulting in insufficient liquid volume at the edge. Moreover, with too large a jetting angle, the air flow coverage range is dispersed, the Coanda effect is weakened, and the droplet trajectory constraint efficiency is reduced.

[0067] It can be known from the comparison between Examples 1, 6, and 7 and Comparative Example 8 that when the distance between the outer edge of the air curtain and the outer edge of the substrate is too large, the escaped droplets exceed the air curtain constraint range and cannot be adsorbed back into the spraying area, resulting in uneven liquid volume in the edge area and exacerbating the component separation due to the volatilization of the droplets in the air.

[0068] As Figure 1 shown, the present invention provides a spraying device for a wet wipe liquid spraying method for wet wipe production, including: an equipment frame 1, a plurality of conveying rollers 2 rotatably connected to the top of the equipment frame 1, and two spraying boxes 3 fixedly segmented on the top of the equipment frame 1; spraying mechanisms and jetting mechanisms are arranged inside both of the two spraying boxes 3. The spraying mechanisms are used to respectively perform pre-wetting spraying and post-high-pressure spraying on the wet wipe substrate, and the jetting mechanisms are used to achieve droplet constraint at the edges of the wet wipe substrate during pre-wetting spraying and post-high-pressure spraying; a power mechanism for driving the plurality of conveying rollers 2 to rotate synchronously is installed on the equipment frame 1.

[0069] It should be noted that the power mechanism is a structure for rotational power transmission, which at least includes a servo motor that provides rotational power, and a power transmission structure located at the output end of the servo motor and one end of several conveying rollers 2. The power transmission structure is one of belt transmission, synchronous belt transmission, or sprocket transmission, which belongs to the common knowledge in the field. Therefore, this application will not explain the control method and specific structure in detail and will not elaborate here; the equipment frame 1 serves as the support structure of the entire spraying equipment, and several conveying rollers 2 are rotatably connected to the top of the equipment frame 1 for conveying the wet wipe substrate. Its power mechanism drives the synchronous rotation of the conveying rollers 2, thereby driving the wet wipe substrate to move on the equipment, enabling pre-wetting spraying and post-high-pressure spraying to be respectively achieved on the wet wipe substrate through two spraying boxes 3, and droplet constraint operations to be achieved at the edges of the wet wipe substrate during pre-wetting spraying and post-high-pressure spraying.

[0070] As Figure 2 and Figure 3 shown, in some specific embodiments, the spraying mechanism includes: several mounting plates 31 fixed inside the spraying box 3, several spraying heads 311 mounted on the mounting plates 31, and an infusion tube 312 fixed on the tops of several spraying heads 311; an infusion head 313 for externally connecting an infusion device to achieve wet wipe liquid supply is mounted on the top of the infusion tube 312.

[0071] It should be noted that several mounting plates 31 are evenly distributed in a linear array along the traveling direction of the wet wipe substrate, and several said spraying heads 311 are evenly distributed in a linear array along the length direction of the mounting plates 31; several mounting plates 31 are fixed inside the spraying box 3 to provide a mounting basis for the spraying heads 311, the infusion tube 312 is fixed on the tops of several spraying heads 311, the infusion head 313 is mounted on the top of the infusion tube 312, and an external infusion device is connected to achieve the supply of wet wipe liquid. The wet wipe liquid enters the infusion tube 312 through the infusion head 313 and then is distributed to each spraying head 311. The spraying heads 311 perform pre-wetting spraying and post-high-pressure spraying on the wet wipe substrate respectively according to predetermined spraying parameters, enabling the wet wipe substrate to evenly absorb the wet wipe liquid and achieve the required spraying effect.

[0072] In some specific embodiments, the air jetting mechanism includes: several mounting rods 32 fixed inside the spraying box 3, several connecting rods 321 arranged at the bottoms of the mounting rods 32, and several air jetting heads 322 arranged on one side of several connecting rods 321; an air supply head 323 for externally connecting an air supply device to achieve gas supply is mounted at the top ends of the air jetting heads 322, and both ends of the connecting rods 321 are connected to the mounting rods 32 and the air jetting heads 322 respectively through pipe clamps for adjusting the jetting direction of the air jetting heads 322.

[0073] It should be noted that the number of jet heads 322 is the same as that of connecting rods 321, and a number of connecting rods 321 are evenly distributed in a linear array; a number of mounting rods 32 are fixed inside the spraying tank 3 to provide a mounting basis for the connecting rods 321 and the jet heads 322. The connecting rods 321 are arranged at the bottom of the mounting rods 32, and the jet heads 322 are arranged on one side of the a number of connecting rods 321. Both ends of the connecting rods 321 are connected to the mounting rods 32 and the jet heads 322 respectively through pipe clamps. The jet direction of the jet heads 322 can be adjusted by adjusting the pipe clamps. The gas delivery head 323 is installed at the top of the jet head 322, and an external gas delivery device is connected to achieve gas supply; during pre-wetting spraying and post-high-pressure spraying, the jet heads 322 eject gas to form an air curtain at the edge of the wet wipe substrate, realizing droplet constraint, preventing the wet wipe liquid from overflowing at the edge of the wet wipe substrate, and ensuring the uniformity and quality of spraying.

[0074] In some specific embodiments, a limiting plate 4 for preventing deviation during the conveyance of the wet wipe substrate is fixed to the side of the spraying tank 3. Conical frames 5 for recovering the wet wipe liquid are installed at the bottoms of the equipment frame 1 and the spraying tank 3, and a recovery pipe 51 is fixed to the bottom of the conical frame 5.

[0075] It should be noted that the limiting plate 4 is made of polytetrafluoroethylene (PTFE) with a smooth surface to reduce friction. It is installed on the inlet and outlet sides of the spraying tank 3, 2-3 mm away from the edge of the substrate, to guide the substrate to be conveyed in the center; for the conical frames 5 at the bottoms of the equipment frame 1 and the spraying tank 3, the wet wipe liquid is collected by gravity into the recovery pipe 51, accelerating the liquid reflux collection, guiding the recovered wet wipe liquid to a designated recovery device, realizing the recycling of the wet wipe liquid, and reducing resource waste and environmental pollution.

[0076] Based on the ideal embodiments of the present invention as inspiration, through the above description, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, in any aspect, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed within the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0077] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for spraying wet wipe liquid in wet wipe production, characterized in that, The spraying method is applicable to the spraying operation of degradable environmental protection wet wipes containing natural ingredient wet wipe solution. The spraying method includes the following steps: S1. Spray the wet wipe solution onto the surface of the wet wipe substrate at a pressure of 0.15 - 0.25 MPa to achieve pre-wetting spraying; S2. After a certain time interval after the low-pressure pre-spraying, spray the remaining total amount of the wet wipe solution onto the pre-wetted wet wipe substrate at a pressure of 0.6 - 0.8 MPa to achieve post-high-pressure spraying; S3. During the pre-wetting spraying and the post-high-pressure spraying, spray gas towards the edge of the wet wipe substrate to form an edge air curtain to restrain droplets.

2. The method for spraying wet wipe liquid in wet wipe production according to claim 1, characterized in that: The natural ingredient wet wipe solution contains saponin or polysaccharide components and has a viscosity of 50 - 200 mPa·s; the substrate of the degradable environmental protection wet wipes is one of bamboo fiber, cotton fiber or non-woven fabric, and the porosity of the substrate is 30 - 70%.

3. The method for spraying wet wipe liquid in wet wipe production according to claim 1, characterized in that: In the step of S1, the duration of the pre-wetting spraying is 1 - 2 s, the droplet diameter is 80 - 120 μm, and the spraying amount is 15 - 30% of the total spraying amount.

4. The method for spraying wet wipe liquid in wet wipe production according to claim 1, characterized in that: The spraying distances of the pre-wetting spraying and the post-high-pressure spraying relative to the wet wipe substrate are 10 - 15 cm, and the spraying interval time between the two is 3 - 6 s.

5. The method for spraying wet wipe liquid in wet wipe production according to claim 1, characterized in that: In the step of S2, the duration of the post-high-pressure spraying is 3 - 4 s, the droplet diameter is 20 - 50 μm, and the spraying amount is 70 - 85% of the total spraying amount.

6. The method for spraying wet wipe liquid in wet wipe production according to claim 1, characterized in that: In the step of S3, the jetting angle of the gas from the outside to the edge direction of the wet wipe substrate is 15 - 30°, the air flow pressure is 0.05 - 0.1 MPa, the air flow velocity is 5 - 8 m / s, and the distance between the edge of the edge air curtain and the edge of the wet wipe substrate is 0 - 13 mm.

7. A spraying device for the method for spraying wet wipe liquid in wet wipe production according to any one of claims 1 - 6, characterized in that, Including: An equipment frame, several conveying rollers rotatably connected to the top of the equipment frame, and two spraying boxes fixedly segmented on the top of the equipment frame; Spraying mechanisms and jetting mechanisms are arranged inside both of the two spraying boxes. The spraying mechanisms are used to respectively achieve pre-wetting spraying and post-high-pressure spraying on the wet wipe substrate, and the jetting mechanisms are used to restrain droplets at the edge of the wet wipe substrate during the pre-wetting spraying and the post-high-pressure spraying; a power mechanism for driving several of the conveying rollers to rotate synchronously is installed on the equipment frame.

8. The spraying device for the method for spraying wet wipe liquid in wet wipe production according to claim 7, characterized in that: The spraying mechanism includes: several mounting plates fixed inside the spraying box, several spraying heads mounted on the mounting plates, and a liquid infusion pipe fixed on the tops of several of the spraying heads; a liquid infusion head for externally connecting an infusion device to supply the wet wipe solution is installed on the top of the liquid infusion pipe.

9. The spraying device for the method for spraying wet wipe liquid in wet wipe production according to claim 7, characterized in that: The jetting mechanism includes: several mounting rods fixed inside the spraying box, several connecting rods arranged at the bottoms of the mounting rods, and several jetting heads arranged on one side of several of the connecting rods; an air supply head for externally connecting an air supply device to supply gas is installed at the top ends of the jetting heads, and both ends of the connecting rods are respectively connected to the mounting rods and the jetting heads through pipe clamps for adjusting the jetting direction of the jetting heads.

10. The spraying device for the method for spraying wet wipe liquid in wet wipe production according to claim 7, characterized in that: A limiting plate for preventing deviation during the conveyance of the wet wipe substrate is fixed to the side of the spraying box. Conical frames for recovering the wet wipe liquid are installed at the bottoms of both the equipment frame and the spraying box, and a recovery pipe is fixed to the bottom of the conical frame.

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