CN118686003A - New process for preparing flushable nonwoven fabrics and its application - Google Patents

Abstract

The present invention provides a preparation method and application of a flushable nonwoven fabric which is energy-saving and maintains clear patterns, comprising: S1: preparing and forming a wet base sheet; S2: embossing the wet base sheet to form an embossed base sheet, the moisture content of the wet base sheet before embossing is: 280%-350%, during embossing, the wet base sheet is vacuum dehydrated, and after embossing, the moisture content of the embossed base sheet is 200%-300%, and the embossing pressure during embossing is (20±2) kgf/cm2; S3: drying the embossed base sheet to form a dry base sheet, the moisture content of the dry base sheet is 6%-9%, through the above settings, especially the control of moisture, the prepared flushable nonwoven fabric has physical property indicators that are basically equivalent to those of existing flushable nonwoven fabrics, and is far superior to existing embossing forms in terms of maintaining clarity, has good softness and hand feel and can reduce energy consumption. The present invention also provides a flushable nonwoven fabric using the above preparation method and a wet wipe using the flushable nonwoven fabric.

Description

New process for preparing flushable nonwoven fabrics and its application

Technical Field

The invention relates to a new process for preparing a flushable nonwoven fabric and the flushable nonwoven fabric and wet wipes prepared by the new process.

Background Art

With the improvement of people's living standards, flushable non-woven products are increasingly widely used in people's daily lives. These flushable non-woven products are mostly used in wet wipes products, such as wet toilet paper products. In further applications, people hope that these products have a more beautiful appearance, so that embossed wet toilet paper products come into being.

However, it is found in practice that for embossed flushable non-woven products, after being soaked in wet wipes liquid for a period of time, the embossed patterns will gradually become unclear or become unclear after being soaked in wet wipes liquid. Therefore, a new process for preparing flushable non-woven fabrics is needed to solve the above technical problems.

Summary of the invention

To this end, the present invention provides a new process for preparing a flushable non-woven fabric to solve the above technical problems.

A new process for preparing a flushable nonwoven fabric, characterized in that it comprises the following steps:

S1: preparing and forming a wet substrate;

S2: embossing the wet substrate to form an embossed substrate, wherein the moisture content of the wet substrate before embossing is 280% to 350%, and after embossing the wet substrate, the moisture content of the embossed substrate is 200% to 300%, and the embossing pressure during the embossing process is (20±2) kgf/cm2;

S3: drying the embossed base sheet to form a dry base sheet, wherein the moisture content of the dry base sheet is 6% to 9%.

The wet base sheet is embossed by a pair of embossing rollers, wherein the embossing rollers include an upper roller and a bottom roller, wherein the upper roller is provided with embossing protrusions corresponding to the embossing pattern, and the bottom roller includes a side wall and a cavity surrounded by the side wall, wherein the side wall is provided with a plurality of micropores penetrating the side wall, and the cavity is in a negative pressure state.

Wherein, the vacuum degree of the cavity is -5 to -12 kPa.

Wherein, the diameter of the micropores on the bottom roller is less than or equal to 1 mm, and the diameter of the micropores is smaller than the diameter of the top surface of the corresponding embossed protrusion.

Wherein, the density of the micropores on the bottom roller is 2 to 10 per cm2, and the micropores are arranged in a spiral shape.

The moisture content of the wet base sheet is in the range of 280% to 350% before embossing, and the moisture content of the embossed base sheet after embossing is in the range of 200% to 280%.

The present invention also provides a flushable nonwoven fabric, which is prepared by applying the new process for preparing the flushable nonwoven fabric.

The present invention also provides a wet wipe, comprising the above-mentioned flushable non-woven fabric and wet wipe liquid.

Wherein, the mass ratio of the wet wipes liquid to the flushable non-woven fabric is 2.8-3.5:1.

Beneficial effects: The present invention adopts a new process for preparing a flushable non-woven fabric, comprising the following steps: S1: preparing and forming a wet base sheet; S2: embossing the wet base sheet to form an embossed base sheet, wherein the moisture content of the wet base sheet before embossing is: 280% to 350%, and after the wet base sheet is embossed, the moisture content of the embossed base sheet is 200% to 300%, and the embossing pressure during the embossing process is (20±2) kgf/cm2; S3: drying the embossed base sheet to form a dry base sheet, and the moisture content of the dry base sheet is 6% to 9%. Through the above-mentioned arrangement, the prepared flushable non-woven fabric is basically equivalent to the physical properties of the existing plain flushable non-woven fabric in terms of physical properties such as flushability. The wet base sheet is embossed under precisely controlled moisture conditions, which is far superior to the existing embossing form in terms of maintaining clarity. The present invention also provides a flushable non-woven fabric using the above-mentioned new process for preparing a flushable non-woven fabric and a wet wipe using the flushable non-woven fabric.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of an embossing roller according to an embodiment of the present invention;

FIG2 is a schematic diagram of the embossing pattern and the position of the through holes during embossing;

Component Description:

Upper roller 11; embossed protrusion 111; embossed pattern 112; bottom roller 12; side wall 121; cavity 122; micropore 123.

DETAILED DESCRIPTION

The embodiment of the present invention provides a new process for preparing a flushable non-woven fabric, which is used to form a flushable non-woven fabric with embossing that can maintain a clear shape after being soaked in wet wipes liquid. The new process includes the following steps.

S1: Prepare and form a wet substrate.

In this embodiment, a wet substrate can be formed in the following manner.

S11: providing fiber raw materials and preparing pulp.

The fiber raw material comprises 12% to 25% of viscose fiber, 3% to 10% of tencel and 60% to 85% of wood pulp fiber, wherein the viscose fiber is 7 to 20 mm long, the tencel fiber is 8 to 15 mm long, and the wood pulp fiber is 1 to 4 mm long.

Furthermore, the viscose fiber is a flat viscose fiber. Specifically, the flat viscose fiber is obtained by dissolving natural fibers in a corresponding solvent and then wet spinning. Compared with round viscose fibers, flat viscose fibers have smaller bending stiffness and are more prone to entanglement. Generally, the fibers in the non-woven fabric substrate can be entangled by virtue of their own physical properties, and the entanglement is a frictional adhesion effect. It can be understood that since flat viscose fibers can be entangled with less external force than round viscose fibers, flat viscose fibers are easier to disperse in water than round viscose fibers.

In addition, the wood pulp fiber is coniferous wood fiber. Generally, coniferous wood fiber has a longer fiber length, and is twisted, entangled, and embraced with viscose fiber, tencel and wood pulp fiber itself to form a dispersible base sheet structure.

The fiber raw materials are dispersed and mixed to form a slurry mixture.

In this embodiment, the viscose fiber is prepared into 0.5% to 0.9% viscose fiber slurry, the tencel is prepared into 0.6% to 0.9% tencel slurry, and the wood pulp fiber is prepared into 2.0% to 5.0% wood pulp slurry.

Then, the viscose fiber pulp, tencel pulp and wood pulp pulp of the above concentrations are mixed to prepare a mixed pulp.

Furthermore, the mixed slurries may be mixed by stirring or the like so that the slurries are mixed evenly.

S12: Forming and hydroentanglement.

The mixed slurry is diluted to a concentration of 0.04% to 0.12%, and transported to a former to form a wet fiber web. Usually, an inclined wire former is used for forming. The vacuum degree of the inclined wire former is -10 to -15 kpa, and the tension of the forming wire is 4 to 8N.

After the wet fiber web is formed, it is reinforced by water entanglement. Usually, the wet fiber web is supported by a water entanglement mesh curtain, and a plurality of water entanglement heads are arranged on the upper side and/or the lower side of the water entanglement mesh curtain. The wet fiber web passes through the plurality of water entanglement heads in sequence. Each water entanglement head includes a plurality of water needles arranged along the width direction of the wet fiber web. The water needles spray high-pressure needle-shaped water flow to impact the wet fiber web, so that the fibers on the wet fiber web are entangled and tangled. At the same time, the high-pressure needle-shaped water flow passing through the wet fiber web is reflected by the cover plate and then passes through the wet fiber web again to entangle and entangle the fibers, thereby finally forming a wet substrate.

Furthermore, there are at least five water jet heads, and the pressures of the high-pressure needle-shaped water streams sprayed by the five water jet heads increase sequentially.

Furthermore, the pressures of the high-pressure needle water flow are 25±5 bar, 35±5 bar, 45±5 bar, 50±5 bar, and 55±5 bar, respectively.

S2: Embossing the wet substrate to form an embossed substrate, wherein the moisture content of the wet substrate before embossing is 280% to 350%, and during embossing, the wet substrate is simultaneously vacuum dehydrated, and after the wet substrate is embossed, the moisture content of the embossed substrate is 200% to 300%, and the embossing pressure during the embossing process is (20±2) kgf/cm2.

Please refer to Figures 1 and 2 together. The wet base sheet is embossed by a pair of embossing rollers. The embossing rollers include an upper roller 11 and a bottom roller 12, wherein the upper roller 11 is provided with an embossing protrusion 111 corresponding to the embossing pattern 112. It can be understood that the embossing protrusion 111 can be a dot-shaped protrusion or a line-shaped protrusion. When the embossing protrusion 111 is a dot-shaped protrusion, the embossing protrusion 111 is in the shape of a truncated cone, and its top surface is circular or elliptical, with an area of 0.2 to 2 mm2 and a height of 0.5 to 4 mm. At the same time, its peripheral cone has a cone angle of 30° to 55°. When the embossing protrusion 111 is a line-shaped protrusion, the embossing protrusion 111 is a long strip of truncated cone, and its top surface has an area of 2 to 15 mm2, and a length of 3 to 25 mm, and the peripheral cone has a cone angle of 30° to 55°.

The bottom roller 12 includes a side wall 121 and a cavity 122 surrounded by the side wall 121. The side wall 121 is provided with a plurality of micro holes 123 penetrating the side wall 121, and the cavity 122 is in a negative pressure state to form the following effects:

1. During the embossing process of the wet substrate, the bottom roller 12 at the lower side forms a drainage effect, thereby reducing the moisture content of the wet substrate.

Second, during the embossing process of the wet substrate, due to the negative pressure, the fibers are shaped during the embossing process.

3. Through vacuum dehydration during the embossing process, the energy consumption in the subsequent drying process is further reduced, saving more than 3% of energy compared to traditional methods.

Furthermore, the vacuum degree of the cavity 122 is -5 to -12 kPa, so that the moisture content of the embossed substrate after embossing is within a suitable range, and the suitable range is the moisture content: 200% to 280%.

At the same time, the embossing pressure during the embossing process is (20±2) kgf/cm2. Combined with the above settings, it was found in further research that when the moisture content is controlled within the range of 280% to 350% of the moisture content of the wet substrate before embossing, during the embossing process, the hydrogen bonds between the fibers in the corresponding area of the embossing are combined and some fibers are entangled or entangled again, so that only the fibers in the corresponding area of the embossing form a tighter bond. At the same time, a lower embossing pressure is used to control the moisture content of the embossed substrate after embossing within the range of 200% to 280%, so that after the subsequent drying process, relatively more consolidated fiber entanglement and fiber deformation are formed only in the corresponding area of the embossing, so that the fibers will not rebound during the re-immersion process, resulting in reduced clarity.

At the same time, since it is necessary to add water-containing wet wipes liquid again when preparing wet wipes, more specifically, the content of the wet wipes liquid is approximately 300%, which is basically equivalent to the moisture content in the wet substrate embossing process. The embossed pattern 112 of the finished wet wipes can maintain a clear shape. In addition, the flushable non-woven fabric prepared by the above preparation method has excellent softness and feel.

Furthermore, the diameter of the micropores 123 on the bottom roller 12 is less than or equal to 1 mm, more preferably, less than or equal to 0.8 mm, more preferably less than or equal to 0.5 mm. At the same time, the diameter of the micropores 123 should be smaller than the top surface diameter of the corresponding embossed protrusions 111.

Furthermore, the micropores 123 on the bottom roller 12 are arranged at a density of 2 to 10 per cm 2 , that is, the micropores 123 are arranged on the bottom roller 12 in a low-density manner.

Furthermore, the micropores 123 are arranged in a spiral form on the bottom roller 12. Please refer to Figure 2. When the micropores 123 are arranged in a spiral form on the bottom roller 12, on the one hand, the embossed protrusions 111 can be reduced to directly correspond to the micropores 123, thereby causing the fibers in the corresponding areas of the micropores 123 to be subjected to greater pressure or to be squeezed and deformed. On the other hand, since the micropores 123 are arranged in a spiral shape, the liquid passing through the micropores 123 during the rotation of the bottom roller 12 is separated from the inside under the action of centrifugal force.

Furthermore, the moisture content of the wet substrate before embossing is 300% to 330%, and after embossing the wet substrate, the moisture content of the embossed substrate is 250% to 280%.

S3: drying the embossed base sheet to form a dry base sheet, wherein the moisture content of the dry base sheet is 6% to 9%.

The embossed substrate is passed through several ovens in sequence, and the temperature difference of adjacent ovens is greater than or equal to 15°C. In a specific embodiment, the ovens include a first oven, a second oven and a third oven, wherein the temperature of the first oven is 105±2°C, the temperature of the second oven is 120±2°C, and the temperature of the third oven is 135±2°C.

Furthermore, a drying cylinder is arranged in the oven, and the embossed substrate is dried by the drying cylinder.

After passing through several ovens, it also includes a hot air penetration drying oven. The embossed substrate is subjected to hot air penetration drying in the hot air penetration drying oven. During the hot air penetration drying process, the hot air temperature is less than or equal to 250°C, and the hot air pressure is less than or equal to 0.1MPa to prevent the embossed structure from being damaged during the hot air penetration process.

The flushable nonwoven fabric of the present application is described below in conjunction with specific embodiments.

Embodiment 1:

S21: preparing and forming a wet base sheet, wherein the fiber raw material comprises 15% of viscose fiber, 4% of tencel and 71% of wood pulp fiber, wherein the viscose fiber has a length of 12.1 mm, the tencel fiber has a length of 14.2 mm, and the wood pulp fiber has a length of 3.7 mm.

S22: Embossing the wet substrate to form an embossed substrate, wherein the moisture content of the wet substrate before embossing is 330%, and after embossing the wet substrate, the moisture content of the embossed substrate is 285%, and the embossing pressure during the embossing process is 19.8kgf/cm2.

The embossing pattern is a linear pattern formed by adjacent embossing points, the negative pressure in the cavity is -8 kPa, the micropore diameter on the bottom roller is 0.5 mm, and the setting density is 8 pores/cm2.

S23: drying the embossed base sheet to form a dry base sheet, wherein the moisture content of the dry base sheet is 8.5%.

Comparative Example 1:

A plain weave nonwoven fabric is prepared with the same raw materials as those in Example 1, wherein the plain weave refers to a product without an embossed pattern.

Comparative Example 2:

The plain weave disintegratable nonwoven fabric product formed in Comparative Example 1 was embossed in a dry state, and the pattern was the same as that in Example 1.

unit Example 1 Comparative Example 1 Comparative Example 2 Basis Weight g/㎡ 61.1 62.2 62.0 Water dispersibility s 216 233 241 Longitudinal dry pull N/m 500 521 502 Transverse dry pull N/m 192 204 188 Longitudinal wet tension N/m 133 140 121 Transverse wet tension N/m 71 77 69 24h clarity / 18/20 / 17/20 7 days clarity / 16/20 / 9/20

Among them, the water dispersibility test is carried out by the following method: pre-treat the sample: according to the INDA/EDANA method, put the sample to be tested into 20L of water, stir for 30 seconds, and conduct a water dispersibility test: add 2L of water (water temperature 22±3℃) into the shaking box, shake the frequency to 33rpm, start the shaking box and start timing, record the time it takes for the sample to disintegrate, and the disintegration is to separate the first small piece of sample from the non-woven fabric.

The test method for the longitudinal dry tensile force and the transverse dry tensile force refers to the test method of "GB/T24218.3-2010 Textile nonwoven fabric test method Part 3: Determination of breaking strength and breaking elongation", wherein the sample width is 50mm, the clamp distance is 100mm, and the tensile speed is 100mm/min.

The longitudinal wet strength and transverse wet strength are measured with reference to the test method of GB/T 12914-2008 Determination of tensile strength of paper and paperboard, wherein the sample width is 50 mm, the clamping distance is 50 mm, and the tensile speed is 100 mm/min.

The clarity is tested in the following manner:

Cut the sample into 10cm×10cm size and fold it;

Add a standard wet wipes liquid equivalent to 300% of the sample weight to the sample. In this test method, the standard wet wipes liquid is water;

The predetermined rest time, in this test method, is 24 hours and 7 days.

Unfold the sample and observe the pattern clarity.

In this test, 20 testers observed the samples separately and evaluated the clarity of the samples. In the above table, 18/20 means that 18 of the 20 testers subjectively evaluated the samples as clear.

From the above test results, it can be seen that the physical properties of the flushable nonwoven fabric with clear embossing provided by the present invention are basically equivalent to those of the existing plain flushable nonwoven fabric, but it is far superior to the existing embossing form in terms of maintaining clarity.

The present invention also provides energy-saving and clear-patterned flushable non-woven fabric using the preparation method, and also provides wet wipes using the flushable non-woven fabric. The wet wipes include the flushable non-woven fabric and wet wipes liquid, wherein the mass ratio of the wet wipes liquid to the flushable non-woven fabric is 2.8 to 3.5:1, which is equivalent to a liquid content of 280% to 350%.

The above description is only an implementation mode of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims (9)

1. The novel process for preparing the flushable non-woven fabric is characterized by comprising the following steps of:

s1: preparing and forming a wet substrate;

S2: embossing the wet substrate to form an embossed substrate, wherein the moisture content of the wet substrate before embossing is as follows: 280% -350%, carrying out vacuum dehydration on the wet substrate at the same time when embossing, wherein after embossing the wet substrate, the water content of the embossed substrate is 200% -300%, and the embossing pressure is (20+/-2) kgf/cm <2 >;

S3: and drying the embossed substrate to form a dry substrate, wherein the moisture content of the dry substrate is 6-9%.

2. The process of claim 1, wherein the wet substrate is embossed by a pair of embossing rollers, the embossing rollers comprise an upper roller and a bottom roller, wherein the upper roller is provided with embossing protrusions corresponding to the embossing patterns, the bottom roller comprises side walls and cavities surrounded by the side walls, the side walls are provided with a plurality of micropores penetrating through the side walls, and the cavities are in a negative pressure state.

3. The novel process for preparing a flushable non-woven fabric according to claim 2, wherein the vacuum degree of the cavity is-5 to-12 kpa.

4. The novel process for preparing a flushable non-woven fabric according to claim 2, wherein the pore diameter of the micropores on the bottom roller is less than or equal to 1mm, and the pore diameter of the micropores is less than the top surface diameter of the embossing protrusions correspondingly arranged.

5. The process for preparing a flushable non-woven fabric according to claim 4, wherein the density of micropores arranged on the bottom roller is 2-10 micropores/cm 2, and the micropores are spirally arranged.

6. The process for preparing a flushable nonwoven fabric of claim 4, wherein the moisture content of the embossed substrate is in the range of 280% to 350% and the moisture content of the wet substrate is in the range of 200% to 280% before embossing.

7. A flushable nonwoven fabric prepared by the novel process for preparing a flushable nonwoven fabric according to claim 1.

8. A wet wipe comprising the flushable nonwoven fabric of claim 7 and a wet wipe liquid.

9. The wet wipe of claim 8 wherein said wet wipe is a flushable nonwoven with a flushable nonwoven

The mass ratio of the cloth is 2.8-3.5:1.