Embossed dust-free paper and preparation method thereof

Abstract

The present invention provides an embossed dust-free paper and a preparation method thereof, wherein the surface of the embossed dust-free paper is pressed with stripes, and the stripes are pressed by a mesh belt with protrusions. The embossed dust-free paper surface of the present invention is softer than the stripes pressed by a grooved roller, and the lateral softness of the product is significantly improved, the product has better fluffiness, has strong diffusivity, and thus obtains excellent dryness. The prepared diversion absorption integrated composite material not only takes into account the rapid absorption of liquid, but also the fibers quickly divert the liquid to the absorption layer, thereby achieving rapid liquid transfer and diffusion.

Description

Technical Field

[0001] The invention belongs to the field of sanitary materials and preparation processes, and in particular relates to embossed dust-free paper and a preparation method thereof. Background Art

[0002] In the field of diapers, sanitary napkins, and adult incontinence, porous nonwoven fabrics are usually used as diversion materials. Some absorbent materials are compressed cores composed of absorbent resin and fluff pulp, and some are five-layer absorbent cores. The diversion material and the absorbent core are bonded together by hot melt adhesive to become the core technical material of the sanitary material. However, the products made by this method have poor wet strength performance of some absorbent cores, and have phenomena such as lumps and faults. Some cores are not easy to diffuse and aggregate in local positions after absorbing liquid. After being under pressure, the liquid reverse osmosis is serious and will cause side leakage. At the same time, the traditional porous nonwoven fabric materials used for diversion are easy to be adsorbed in the pores of the nonwoven fabric materials during the diversion process. These liquids absorbed by the pores will cause high reverse osmosis values ​​and affect the surface dryness performance. In addition, the addition of hot melt adhesive not only increases the economic cost but also greatly affects the absorption effect of the liquid. Summary of the invention

[0003] In view of this, the present invention aims to overcome the drawbacks of the materials in the prior art. The embossed dust-free paper is produced by pressing stripes on the dust-free paper material with a mesh belt with projections. The dust-free paper has strong diffusivity and thus obtains excellent dryness, which effectively improves the defects of the existing materials. The present invention has not been reported on the market.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] According to a first aspect of the present invention, there is provided an embossed dust-free paper, wherein stripes are pressed on the surface of the embossed dust-free paper, and the stripes are pressed by a mesh belt with protrusions.

[0006] Furthermore, the mesh belt with protrusions includes a mesh belt substrate and protrusions arranged on the surface of the mesh belt substrate and parallel to its movement direction. The material of the mesh belt substrate and the material of the protrusions can be selected from polymer plastic materials (such as polyester, PPS, nylon, etc.) or metal, etc. In a specific embodiment of the present invention, the material of the mesh belt substrate is polyester.

[0007] Furthermore, the mesh size of the mesh belt substrate is 6-50 meshes, and more preferably 9-18 meshes.

[0008] Furthermore, the mesh belt base material is woven, and the protrusions are woven into the mesh belt base material or fixed on the surface of the mesh belt base material.

[0009] Furthermore, the distance between two adjacent protrusions is 0.5-20 mm, the width of a protrusion is 0.2-20 mm, and the height of a protrusion is 0.2-5 mm.

[0010] Preferably, the distance between two adjacent protrusions is 1-10 mm, the width of a protrusion is 1-10 mm, and the height of a protrusion is 0.5-2.0 mm.

[0011] The second aspect of the present invention provides a preparation process for the embossed dust-free paper, comprising the following steps: pressing the pre-pressed layer including one or more layers of dust-free paper raw materials into stripes before or after hot air drying, wherein the stripes are pressed using a mesh belt with protrusions.

[0012] The third aspect of the present invention provides an embossed dust-free paper prepared by the above-mentioned preparation process, wherein the basis weight of the embossed dust-free paper is 25-400 g / m 2 , thickness is 0.3-8mm, tensile strength is not less than 10N / 5cm, liquid penetration speed is not more than 3 seconds, and liquid absorption capacity is greater than 10g / g distilled water.

[0013] In a fourth aspect of the present invention, there is provided disposable sanitary products prepared from the embossed dust-free paper, including but not limited to women's sanitary products, adult incontinence products, diapers, food pads (such as fish pads, meat pads, etc.), and pet pads.

[0014] A fifth aspect of the present invention provides a process for preparing a flow-guiding and absorbing integrated composite material, comprising the following steps:

[0015] S1: spreading one or more layers of absorbent layer raw materials layer by layer and pre-pressing them to form a pre-pressed layer;

[0016] S2: Pressing the surface of the pre-pressed layer into stripes by a pressing roller with a mesh belt with protrusions on the surface, covering the surface of the pre-pressed layer with the guide layer material, and then sending it into a hot air drying device for drying and curing to obtain a composite layer; or

[0017] S3: Covering the guide layer material on the surface of the pre-pressed layer and sending it into a hot air drying device for drying and curing, and then pressing the surface of the pre-pressed layer with stripes by a pressing roller with a mesh belt with protrusions wound on the surface to obtain a composite layer;

[0018] S4: spraying water, drying, cooling and winding the composite layer to obtain a flow-guiding and absorbing integrated composite material.

[0019] Preferably, the mesh belt with protrusions in step S2 comprises a mesh belt substrate and protrusions arranged on the surface of the mesh belt substrate and parallel to the moving direction thereof.

[0020] Preferably, the mesh belt substrate is woven, and the protrusions are woven into the mesh belt substrate or fixed on the surface of the mesh belt substrate. The material of the mesh belt substrate and the protrusions can be selected from polymer plastic materials (such as polyester, PPS, nylon, etc.) or metals, etc. In a specific embodiment of the present invention, the material of the mesh belt substrate is polyester.

[0021] Preferably, the distance between two adjacent protrusions is 0.5-20 mm, the width of a protrusion is 0.2-20 mm, and the height of a protrusion is 0.2-5 mm.

[0022] More preferably, the distance between two adjacent protrusions is 1-10 mm, the width of a protrusion is 1-10 mm, and the height of a protrusion is 0.5-2.0 mm.

[0023] Preferably, the pressure of the pressing roller in step S2 is 5-50 N / mm, more preferably 10-40 N / mm.

[0024] Preferably, the temperature of the hot air drying device in step S3 is set to 110-150°C.

[0025] Preferably, the absorbent layer raw material in step S1 is spread layer by layer on the surface of the support layer, and the material of the support layer is air-permeable wadding paper.

[0026] Preferably, the raw material of the absorption layer includes cellulose fibers and bicomponent composite fibers and a polymer water-absorbing resin may be optionally added.

[0027] Preferably, the guide layer material is a porous nonwoven material.

[0028] Preferably, the porous nonwoven material is a carded hot air nonwoven fabric, a carded chemically bonded nonwoven fabric, a perforated nonwoven fabric or a spunlace nonwoven fabric.

[0029] Preferably, the cellulose fiber is one or a mixture of two or more of treated or untreated fluff pulp, coniferous wood pulp, hardwood pulp, straw pulp, chemical pulp, chemimechanical pulp, and thermomechanical pulp, has a length of 2-5 mm, and has various forms.

[0030] Preferably, the bicomponent composite fiber is a mixture of one or more of polypropylene-polyethylene copolymer, polyethylene terephthalate-polyethylene copolymer, polyethylene terephthalate-polypropylene copolymer, and the bicomponent composite fiber has a length of 2.5-10 mm, a fineness of 1.0-17 dtex, and a variety of cross-sectional structures.

[0031] Preferably, the polymer water-absorbing resin is a sodium polyacrylate mixture prepared by aqueous solution polymerization.

[0032] In a sixth aspect of the present invention, there is provided disposable sanitary products prepared from the above composite material, including but not limited to women's sanitary products, adult incontinence products, diapers, food pads (such as fish pads, meat pads, etc.), and pet pads.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] (1) The surface of the dust-free paper of the present invention is processed by pressing stripes with a mesh belt with protrusions, which is softer and has better fluffiness than dust-free paper with stripes pressed with grooved rollers. Because the grooved rollers are generally made of steel, the stripes pressed by the two steel rollers on both sides of the material are directly in contact with each other without gaps under pressure, and the stripes will be relatively stiff; while the process principle of pressing stripes with a mesh belt with protrusions is that one side of the material is in direct contact with one of the steel rollers, and the other side of the material is in direct contact with the mesh belt wrapped around the roller; the woven mesh belt is made of polymer plastic material as a whole, and has fine pores during the weaving and molding process, which allows the pre-pressed layer material to have a certain buffer space under pressure, so that the product has better fluffiness and air permeability, thereby giving the material a faster liquid absorption rate.

[0035] (2) The mesh belt with protrusions of the present invention may have a mesh belt substrate of one layer or more layers. The number of layers of the mesh belt substrate will affect the softness of the pressed dust-free paper and the density of the grooves, and embossed dust-free paper with different properties can be flexibly designed.

[0036] (3) After the dust-free paper of the present invention is processed by a pressure roller with a mesh belt with projections wrapped around its surface, it is given a higher density as a whole, and the stripes of the material itself also form a high and low density difference, so the liquid diffuses quickly along the stripes after being absorbed, and at the same time, the liquid will not seep back after being pressed, thereby achieving a dry and refreshing experience for consumers.

[0037] (4) During the online compounding process of the guide layer material and the absorption layer material in the guide layer and absorption integrated composite material described in the present invention, the wood pulp fibers can be embedded into the gaps of the guide layer material and fully interwoven through vacuum suction and hot air from an oven, and then the two layers of materials are compounded into one through the thermal bonding of the two-component fibers. This process molding feature enables the composite material to quickly absorb liquid while the fibers quickly guide the liquid to the absorption layer, thereby achieving rapid transfer and diffusion of the liquid.

[0038] (5) The guide layer material in the guide absorption integrated composite material of the present invention generally adopts the combed hot air non-woven fabric, combed chemical bonding non-woven fabric, perforated non-woven fabric or spunlace non-woven fabric and other materials, which are porous and are not subjected to pressure and extrusion by rollers or other methods during the online composite process with the absorption layer material, retaining the porous spatial structure of the material itself, giving the material the best absorption speed. Therefore, once it comes into contact with the liquid, it can absorb it quickly, and at the same time temporarily store the liquid in the gap, preparing for the absorption layer to play a role and avoiding side leakage.

[0039] (6) The preparation process of the guide and absorbent integrated composite material described in the present invention combines the guide layer material and the absorbent layer material into one, which is not easy to delaminate to meet the requirements of subsequent processing. Moreover, the material will not break, clump, or become uneven after absorbing a large amount of liquid during use.

[0040] (7) The guide layer material of the guide absorption integrated composite material described in the present invention is fluffy, soft and porous, and the pores are much larger than those of the absorption layer. In this way, a certain density gradient is formed inside the composite material of the present invention. When absorbing liquid, the surface liquid absorption point (Stain Size) of the product is small. Due to the novel and special gradient design, the absorbed liquid can quickly diffuse after passing through the guide layer. This effect enables the product to achieve a small surface liquid point area when absorbing liquid, and a large liquid absorption area in the absorption layer connected thereto, thus giving the terminal product (such as a sanitary napkin) a smaller surface visual effect, which is also one of the reasons why the product of the present invention has good re-seepage performance.

[0041] (8) The mixture of cellulose fibers and bicomponent composite fibers in the embossed dust-free paper of the present invention is fully stirred and then sprinkled onto the support layer. This process feature is also conducive to the diffusion of liquid.

[0042] (9) The guide layer of the composite material of the present invention is made of non-woven fabric, the middle layer is made of cellulose fiber and bicomponent composite fiber evenly mixed, and the bottom layer is made of low-weight lining paper with good air permeability, so that the surface uniformity and hand feel of the material are good and dust is significantly reduced.

[0043] (10) The composite material prepared by the method of the present invention can adapt to the high-speed production line in the field of sanitary materials, and the integrity of the guide layer and the absorption layer overcomes the complexity of online matching and compounding of the non-woven fabric and the absorbent core by adding hot melt adhesive, while avoiding the influence of hot melt adhesive on the absorption performance of the material, saving raw materials, and having good economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the preparation process of embossed dust-free paper embodiment 1;

[0045] Figure 2Schematic diagram of the preparation process of embossed dust-free paper embodiment 2;

[0046] Figure 3 A schematic diagram of the preparation process of Example 1 of the flow-guiding and absorption integrated composite material;

[0047] Figure 4 A schematic diagram of the preparation process of Example 2 of the flow-guiding and absorption integrated composite material;

[0048] Figure 5 It is a structural schematic diagram of the mesh belt of the present invention;

[0049] Figure 6 Another structural schematic diagram of the mesh belt of the present invention;

[0050] Figure 7 This is a scanning electron microscope image of the composite layer of Example 1 of the flow-guiding and absorption integrated molding composite material after being dry-cured in the first heating oven.

[0051] Description of reference numerals:

[0052] 1. First unwinder; 2. First forming head; 3. First pre-pressing roller; 4. Second forming head; 5. Third forming head; 6. Second pre-pressing roller; 7. First hot pressing roller; 8. Second unwinder; 9. Mesh belt; 9-1. Mesh belt substrate; 9-2. Protrusion; 10. First heating oven; 11. Second hot pressing roller; 12. First nozzle; 13. Second heating oven; 14. Third heating oven; 15. Paper winder; 16. Second nozzle. DETAILED DESCRIPTION

[0053] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0054] The present invention will be described in detail below with reference to the embodiments.

[0055] In the present invention, the absorption speed, diffusion length and reverse osmosis amount of the samples prepared in the embodiments and comparative examples were tested.

[0056] The test performance indicators are as follows:

[0057] 1. Absorption rate: Refer to the requirements for absorption rate in sanitary napkins (panty liners) in the National Standard of the People's Republic of China GB / T 8939-2018.

[0058] 2. Diffusion length: Let the sample with absorption rate tested stand for 5 minutes, observe and measure the length of the solution diffusion along the material longitudinally (record the highest diffusion point), in millimeters.

[0059] 3. Reverse osmosis: Let the sample with tested absorption speed stand for 5 minutes, put filter paper on it, then press a 1.2kg weight on it, let it stand for 1 minute, weigh the filter paper, and the weight change is the reverse osmosis value in grams.

[0060] 4. Stiffness: also known as flexural rigidity. The change in curvature when a specimen of unit width is bent to a fixed angle due to its own weight. The specific test method for stiffness is as follows (DANA50.6-02).

[0061] 4.1 Stiffness tester: Contains a test platform, which must be coated or covered with polytetrafluoroethylene, with a side bevel angle of 41.5°; single-sided adhesive slide ruler.

[0062] 4.2 Sample requirements

[0063] 4.2.1 Specimen size: (25 ± 1) mm × (250 ± 1) mm.

[0064] 4.2.2 Number of specimens: 6 pieces.

[0065] 4.2.3 The specimen is required to be equilibrated under constant temperature and humidity conditions for at least 4 hours.

[0066] Note: If the test is to be performed online in real time, no balancing is required, but the temperature and humidity at that time should be recorded for reference while measuring.

[0067] 4.3 Test steps

[0068] 4.3.1 Carry out sampling, sampling and cutting according to product requirements;

[0069] 4.3.2 Place a single specimen flat on the platform (if it is a specimen with non-woven fabric, the non-woven fabric should face downward), press the specimen with a ruler with single-sided adhesive, and align one end of the specimen with the zero point of the ruler on the platform;

[0070] 4.3.3 Push the ruler forward along the scale direction. The specimen will sag due to its own weight during the movement. Continue to push until the other end of the specimen is close to the groove on the side of the platform.

[0071] 4.3.4 Stay for 10 seconds, observe and adjust so that the position of the sample end and the side groove are close but not connected, and record the scale reading C at this time;

[0072] 4.3.5 After completing the above measurements, another measurement should be carried out from the other end of the sample using the same method as above; if the sample is a non-woven fabric sample, only the single-side value is measured.

[0073] 4.4 Result calculation

[0074] S = (Avg C / 2)3 ×GSM×10 -3

[0075] Where: S: sample stiffness m·Ncm;

[0076] Avg C: The average value of the hanging length of the sample, that is, after the sample is measured on both ends of the single side, four values ​​of C1 and C2 are obtained, and their average value is calculated. If it is a non-woven material, two values ​​of C1 and C2 are obtained, and their average value is also calculated;

[0077] GSM: The quantitative weight of the sample g / m 2 .

[0078] The structure of the mesh belt with projections used in the embodiments and comparative examples is as follows: Figure 3 As shown, it includes a mesh belt base material 9-1 woven by warp and weft and a protrusion 9-2 parallel to its moving direction. The protrusion 9-2 is woven in the mesh belt base material 9-1. The materials of the mesh belt base material 9-1 and the protrusion 9-2 are both plastic. Specifically, the material of the mesh belt base material 9-1 is polyester, and the material of the protrusion 9-2 is polyester. The mesh belt base material 9-1 can be woven into a single-layer mesh or a multi-layer mesh. The mesh belt 9 with protrusions can be directly put on the surface of the first hot pressing roller 7, or it can form an endless mesh belt wrapped around the guide roller and the first hot pressing roller 7. Of course, it can also be based on actual working conditions, such as Figure 4 As shown, the protrusions 9-2 are arranged on the surface of the mesh belt substrate 9-1 by secondary weaving or secondary fixing.

[0079] 1. Preparation and testing of embossed dust-free paper

[0080] Example 1

[0081] The total weight of the embossed dust-free paper in this embodiment is about 160 g / m 2 , thickness is about 1.55mm, its specific raw materials and structure are as follows: cellulose fiber is Weyerhauser NB416, fiber length is about 2-5mm; bicomponent composite fiber is composed of core layer and skin layer, core layer is polypropylene (PET), skin layer is polyethylene (PE), fiber length is about 3-6mm, fineness is about 1.7-3.0 dtex; polymer water-absorbing resin (SAP) is Formosa Plastics GK402 model, the main component is sodium polyacrylate mixture, its average particle size is 314 um. Among them, the dust-free paper passes through the surface of the mesh belt roller with protrusions, among which the mesh belt with protrusions uses mesh belt substrate 9-1 as a single-layer mesh, mesh belt substrate 9-1 has a mesh number of 12 meshes, protrusions 9-2 are circular, the spacing between adjacent protrusions is 5mm, the width of the protrusions is 1.2mm, the height of the protrusions is 1.2mm, the pressure of the roller is 40N / mm; the oven temperature is controlled at 130℃.

[0082] The material structure design is shown in Table 1. The weight of the first fiber layer accounts for about 31.5% of the total weight of the product, the weight of the second fiber layer accounts for about 31.44% of the total weight of the product, and the weight of the third fiber layer accounts for about 37.06% of the total weight of the product. The distribution of each component in each layer is shown in Table 1 below. The proportions in the table are expressed by the mass percentage of each material in the layer.

[0083] Table 1 Ratio of components in each layer

[0084]

[0085] The preparation process of the above materials is as follows (equipment diagram as shown in Figure 1 shown):

[0086] In the forming area, cellulose fibers, bicomponent composite fibers and high molecular water-absorbing resin (SAP) are first sent to the first forming head 2 (horizontal screen forming head) for uniform mixing. Through airflow forming and vacuum suction, the mixture passes through the first forming head 2 and is evenly spread on the forming mesh belt. A first pre-pressing roller 3 is designed between the first forming head 2 and the second forming head 4 (horizontal screen forming head) to selectively pre-press the pre-pressing layer to a certain extent.

[0087] Then, the pre-pressed layer is transferred to the second forming area, and the bi-component composite fiber and the cellulose fiber are uniformly mixed in the second forming head 4, and are spread on the first fiber layer by air forming and vacuum suction; after passing through the second forming area, the composite layer is transferred to the third forming area, and the bi-component composite fiber and the cellulose fiber are uniformly mixed in the third forming head 5 (horizontal screen type forming head), and are spread on the first two composite fiber layers by air forming and vacuum suction;

[0088] The pre-pressed layer of dust-free paper formed above is passed through the second pre-pressing roller 6 to further stabilize the structure, and then passed through the first hot pressing roller 7 to be transported to the second nozzle 16 to spray latex on the upper surface of the dust-free paper, and then transported to the first heating oven 10 for drying and curing, and then passed through a pressing roller with a raised mesh belt 9 on the surface to press stripes on the dust-free paper, turn, and be transported to the first nozzle 12 to spray latex on the lower surface of the dust-free paper, and then sent to the second heating oven 13 and the optional third heating oven 14 for continued heating, drying and curing to form a product; after the product is cooled, it is wound into a roll by a paper winder 15; as required, it is cut into products of different widths by a slitting machine.

[0089] The composite material of this example was tested for various properties, and the results are shown in Table 1.

[0090] Example 2

[0091] Example 2 is carried out in basically the same manner as Example 1, except that the mesh belt substrate is a double-layer mesh belt, the mesh belt substrate has a mesh size of 9, the protrusion spacing is 0.5mm, the protrusion width is 0.2mm, and the protrusion height is 0.2mm.

[0092] Example 3

[0093] The specific raw materials and structures of the embossed dust-free paper in this embodiment are the same as those in Embodiment 1, except that the mesh number of the mesh belt substrate is 18 meshes, the pitch of the protrusions is 20 mm, the width of the protrusions is 20 mm, and the height of the protrusions is 5 mm.

[0094] In addition, the preparation process of the embossed dust-free paper in this embodiment is different from that in embodiment 1. The specific preparation process is as follows (the equipment diagram is as follows: Figure 2 shown):

[0095] In the forming area, cellulose fibers, bicomponent composite fibers and high molecular water-absorbing resin (SAP) are first sent to the first forming head 2 (horizontal screen forming head) for uniform mixing. Through airflow forming and vacuum suction, the mixture passes through the first forming head 2 and is evenly spread on the mesh belt. A first pre-pressing roller 3 is designed between the first forming head 2 and the second forming head 4 (horizontal screen forming head) to selectively pre-press the pre-pressing layer to a certain extent.

[0096] Then, the pre-pressed layer is transferred to the second forming area, and the bi-component composite fiber and the cellulose fiber are uniformly mixed in the second forming head 4, and are spread on the first fiber layer by air forming and vacuum suction; after passing through the second forming area, the composite layer is transferred to the third forming area, and the bi-component composite fiber and the cellulose fiber are uniformly mixed in the third forming head 5 (horizontal screen type forming head), and are spread on the first two composite fiber layers by air forming and vacuum suction;

[0097] The dust-free paper pre-pressed layer, i.e., the absorption layer, formed above, is passed through the second pre-pressing roller 6 to further stabilize the structure, and then passed through the first hot pressing roller 7 and then passed through a pressing roller with a raised mesh belt wound around the surface to press stripes on the dust-free paper and be transported to the second nozzle 16 to spray latex on the upper surface of the dust-free paper, and then transported to the first heating oven 10 for drying and curing, turned, and transported to the first nozzle 12 to spray latex on the lower surface of the dust-free paper, and then sent to the second heating oven 13 and the optional third heating oven 14 for continued heating, drying and curing to form a product; after the product is cooled, it is wound into a roll by a paper winder 15; as required, it is cut into products of different widths by a slitting machine.

[0098] The embossed dust-free paper of this embodiment was tested for various properties, and the results are shown in Table 2.

[0099] Example 4

[0100] Example 4 is carried out in basically the same manner as Example 1, except that the mesh size of the mesh belt substrate is 6 meshes, the spacing between adjacent protrusions is 1 mm, the width of the protrusions is 1 mm, the height of the protrusions is 0.5 mm, the pressure of the pressure roller is 10 N / mm, and the oven temperature is controlled at 110°C.

[0101] Example 5

[0102] Example 5 is carried out in basically the same manner as Example 1, except that the mesh size of the mesh belt substrate is 50 mesh, the spacing between adjacent protrusions is 10 mm, the width of the protrusions is 10 mm, the height of the protrusions is 2 mm, the pressure of the pressure roller is 50 N / mm, and the oven temperature is controlled at 150°C.

[0103] Comparative Example 1

[0104] The raw material ratios of the products of Comparative Example 1 are basically the same as those of Example 1, except that the material is not subjected to stripe pressing by a mesh belt with projections.

[0105] Comparative Example 2

[0106] Comparative Example 2 is produced in basically the same manner as Example 1 with respect to the raw material ratio of the product, except that: a mesh belt with projections is no longer used, and the stripes of the material are pressed by a grooved roller, wherein the spacing between adjacent projections is 5 mm, the width of the projection is 1.2 mm, the height of the projection is 1.2 mm, and the pressure of the pressing roller is 40 N / mm; and the oven temperature is controlled at 130°C.

[0107] Comparative Example 3

[0108] Comparative Example 3 was carried out in substantially the same manner as Example 1, except that the spacing between adjacent protrusions was 0.2 mm.

[0109] Comparative Example 4

[0110] Comparative Example 4 was carried out in substantially the same manner as Example 1, except that the spacing between adjacent protrusions was 25 mm.

[0111] Comparative Example 5

[0112] Comparative Example 5 was carried out in substantially the same manner as Example 1, except that the width of the protrusion was 0.1 mm.

[0113] Comparative Example 6

[0114] Comparative Example 6 was carried out in substantially the same manner as Example 1, except that the width of the protrusion was 25 mm.

[0115] Comparative Example 7

[0116] Comparative Example 7 was carried out in substantially the same manner as Example 1, except that the height of the protrusions was 0.1 mm.

[0117] Comparative Example 8

[0118] Comparative Example 8 was carried out in substantially the same manner as Example 1, except that the height of the protrusions was 6 mm.

[0119] Comparative Example 9

[0120] Comparative Example 9 was carried out in substantially the same manner as Example 1, except that the mesh size of the mesh belt was 5 meshes.

[0121] Comparative Example 10

[0122] Comparative Example 10 was carried out in substantially the same manner as Example 1, except that the mesh size of the mesh belt was 55 meshes.

[0123] The embossed dust-free paper materials in Examples 1 to 5 and Comparative Examples 1 to 10 were tested for absorption rate, diffusion length, reverse osmosis value and stiffness value. The service life of the mesh belt and whether the stripes pressed on the surface of the product were offset in the longitudinal direction were evaluated. The results are shown in Table 2.

[0124] Table 2 Performance test results of embossed dust-free paper

[0125]

[0126] It can be seen from Table 2 that when the mesh number of the mesh belt exceeds 50 meshes, the service life of the mesh belt drops sharply and the economy is poor. At the same time, when the mesh number is too small, such as 6 meshes, the service life of the mesh belt is slightly improved, but the dimensional stability of the mesh belt is very poor, resulting in a large deviation of the pressed stripes in the longitudinal direction of the product, resulting in waste; in the embodiments and comparative examples, the absorption speed, diffusion length, reverse osmosis performance and softness of the dust-free paper with pressed stripes in Examples 1 to 5 all reach a relatively excellent level, among which Example 1 has the best comprehensive performance.

[0127] 2. Preparation and testing of flow-guiding and absorption integrated composite materials.

[0128] Example 6

[0129] The total weight of the composite material in this embodiment is about 175 g / m 2, thickness is about 2.30mm, its specific raw materials and structure are as follows: non-woven fabric uses 35gsm hot air non-woven fabric; cellulose fiber uses WeyerhauserNB416, fiber length is about 2-5mm; bicomponent composite fiber consists of core layer and skin layer, core layer is polypropylene (PET), skin layer is polyethylene (PE), fiber length is about 3-6mm, fineness is about 1.7-3.0 dtex; polymer absorbent resin (SAP) uses Formosa Plastics GK402 model, the main component is sodium polyacrylate mixture, its average particle size is 314 um; lining paper uses Yinge 13gsm high air permeability wadding paper. The absorption layer and lining paper are wrapped with a single-layer mesh belt with protrusions on the surface, the mesh belt has 12 meshes, the protrusion spacing is 5mm, the protrusion width is 1.2mm, the protrusion height is 1.2mm, and the pressure of the first hot pressing roller 7 is controlled at 40N / mm; the oven temperature is controlled at 130℃.

[0130] The structural design of the composite material is shown in Table 3. The basis weight of the guide layer accounts for about 20% of the total basis weight of the product, the basis weight of the first fiber layer accounts for about 26.29% of the total basis weight of the product, the basis weight of the second fiber layer accounts for about 25.14% of the total basis weight of the product, the basis weight of the third fiber layer accounts for about 21.14% of the total basis weight of the product, and the backing paper accounts for about 7.43% of the total basis weight of the product. The distribution of each component in each layer is shown in Table 3 below. The proportions in the table are expressed by the mass percentage of each material in the layer.

[0131] Table 3 Ratio of components in each layer

[0132]

[0133] The preparation process of the above composite material is as follows (equipment diagram as shown in Figure 3 shown):

[0134] First, the highly air-permeable backing paper is conveyed to the forming area and other subsequent processes by the first unwinding machine 1. The forming area is continuously conveyed by an endless conveyor belt. After the operation is stable, the cellulose fiber, the two-component composite fiber and the polymer absorbent resin (SAP) are sent to the first forming head 2 for uniform mixing. Through airflow forming and vacuum suction, the mixture passes through the first forming head 2 and is evenly spread on the backing paper. The first pre-pressing roller 3 is designed between the first forming head 2 and the second forming head 4 to selectively pre-press the initial composite layer.

[0135] Then, the pre-pressed layer is transferred to the second forming area, and the composite fiber, cellulose fiber and high molecular water-absorbing resin (SAP) are sent to the second forming head 4 for uniform mixing, and are spread on the backing paper and the first fiber layer through air forming and vacuum suction; after passing through the second forming area, the composite layer is transferred to the third forming area, and the two-component composite fiber and cellulose fiber are uniformly mixed by the third forming head 5, and are spread on the first two composite fiber layers through air forming and vacuum suction;

[0136] The pre-pressed layer, i.e., the absorbent layer, formed above, is passed through the second pre-pressing roller 6 to further stabilize the structure, and then the pre-pressed layer is pressed into stripes by the first hot pressing roller 7 and the mesh belt with protrusions 9, and then transported to the first heating oven 10 to heat and bond with the hot air non-woven fabric on the second unwinder 8 to form interlayer bonding strength. At this time, the composite material has been completely composited online; the scanning electron microscope image of the composite material after drying and curing in the first heating oven 10 is as follows Figure 7 As shown, it can be seen that under certain pressure control, the wood pulp fibers can be embedded into the gaps of the guide layer material and fully interwoven through vacuum suction and hot air penetration in the oven, and then the two layers of materials are compounded into one through the thermal bonding of the two-component fibers. This process molding feature allows the gradient material to quickly absorb liquid while the interwoven layer of wood pulp fibers quickly guides the liquid to the absorbent dust-free paper layer, thereby achieving rapid liquid transfer and diffusion.

[0137] After passing through the first heating oven 10, the composite material is turned and transported to the first nozzle 12, where water is sprayed on the outer surface of the absorbent layer liner to form a hydrogen bond between the liner and the fiber layer. The composite material is then sent to the second heating oven 13 and the optional third heating oven 14 for further heating, drying and curing to form a composite material product. After the composite material product is cooled, it is wound into a roll by a paper winder 15. According to demand, it is cut into products of different widths by a slitting machine.

[0138] The composite material product of this embodiment was tested for various properties, and the results are shown in Table 4.

[0139] Example 7

[0140] This embodiment is carried out in a manner similar to that of the product raw material ratio of embodiment 6, except for the preparation process. The preparation process of the composite material of this embodiment is as follows:

[0141] First, the highly air-permeable backing paper is conveyed to the forming area and other subsequent processes by the first unwinding machine 1. The forming area is continuously conveyed by an endless conveyor belt. After the operation is stable, the cellulose fiber, the two-component composite fiber and the polymer absorbent resin (SAP) are sent to the first forming head 2 (horizontal screen type) for uniform mixing. Through airflow forming and vacuum suction, the mixture passes through the first forming head 2 and is evenly spread on the backing paper. The first pre-pressing roller 3 is designed between the first forming head 2 and the second forming head 4 to selectively pre-press the initial composite layer.

[0142] Then, the pre-pressed layer is transferred to the second forming area, and the composite fiber, cellulose fiber and high molecular water-absorbing resin (SAP) are sent to the second forming head 4 for uniform mixing, and are spread on the backing paper and the first fiber layer through air forming and vacuum suction; after passing through the second forming area, the composite layer is transferred to the third forming area, and the two-component composite fiber and cellulose fiber are uniformly mixed by the third forming head 5, and are spread on the first two composite fiber layers through air forming and vacuum suction;

[0143] The pre-pressed layer, i.e., the absorbent layer, formed as above, is passed through the second pre-pressing roller 6 to further stabilize the structure, and then through the first hot pressing roller 7, the pre-pressed layer is transported to the first heating oven 10 to heat and bond with the hot air non-woven fabric on the second unwinder 8 to form interlayer bonding strength. At this time, the composite material has been completely composited online; after passing through the first heating oven 10, the composite material is pressed by the pressing roller of the wound raised mesh belt 9 to press the stripes as a whole, turn, and be transported to the first nozzle 12, and water is sprayed on the outer surface of the absorbent layer lining paper to form hydrogen bonding force between the lining paper and the fiber layer, and then it is sent to the second heating oven 13 and the optional third heating oven 14 for further heating, drying and curing to form a composite material product; after the composite material product is cooled, it is wound into a roll by the paper reel 15; according to demand, it is cut into products of different required widths by a slitting machine.

[0144] The composite material product of this embodiment was tested for various properties, and the results are shown in Table 4.

[0145] Comparative Example 11

[0146] This comparative example was prepared in substantially the same manner as the raw material ratio of Example 6, except that:

[0147] The product has no stripes, that is, the first hot pressing roller 7 is a smooth roller. After the absorption layer passes through the first hot pressing roller 7 to further stabilize the structure, it is directly transported to the first heating oven 10 to heat and bond with the hot air nonwoven fabric on the second unwinder 8 to form interlayer bonding strength.

[0148] The composite material product of this comparative example was tested for various properties, and the results are shown in Table 4.

[0149] Comparative Example 12

[0150] Comparative Example 12 was prepared in substantially the same manner as in Example 6, except that:

[0151] The first hot pressing roller is an embossing roller (groove roller), which is used to press stripes on the pre-pressed layer. Then, a temporary spraying device is used to spray hot melt adhesive on the upper surface of the absorbent layer (simulating the bonding method between the guide layer and the absorbent layer in the finished sanitary napkin), and then it is transported to the first heating oven 10 for heating and bonding with the hot air non-woven fabric on the second unwinder 8.

[0152] The composite material product of this comparative example was tested for various properties, and the results are shown in Table 4.

[0153] Comparative Example 13

[0154] Comparative Example 13 was prepared in substantially the same manner as in Example 6, except that:

[0155] The first hot pressing roller is an embossing roller (groove roller), which presses the pre-pressed layer into stripes through the groove roller and then conveys it to the first heating oven 10 to be heated and bonded with the hot air non-woven fabric on the second unwinder 8.

[0156] The composite material product of this comparative example was tested for various properties, and the results are shown in Table 4.

[0157] The composite materials prepared in Examples 6, 7 and Comparative Examples 11-13 were tested for absorption rate, diffusion length, reverse osmosis value and stiffness value. The results are shown in Table 4.

[0158] Table 4 Performance test results of composite materials

[0159]

[0160] It can be seen from Table 4 that Example 6 exhibits the best comprehensive performance, among which the absorption speed has a significant advantage. The reason is that the hot air non-woven fabric maintains the porous structure of the material itself without being pressed. Due to the characteristics of the molding process, the absorption layer fibers of the diversion and absorption integrated material can penetrate into the non-woven fabric layer to help the liquid to be quickly absorbed. At the same time, the absorption layer is pressed through stripes to make the infiltrated liquid quickly diffuse along the longitudinal direction of the material, thereby achieving an excellent reverse osmosis effect. In addition, the small liquid absorption points on the surface of the diversion material can also play a shielding role.

[0161] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An embossed dust-free paper, characterized in that: The surface of the embossed dust-free paper is pressed with stripes, and the stripes are pressed by a mesh belt with protrusions; the mesh belt with protrusions includes a mesh belt substrate and protrusions arranged on the surface of the mesh belt substrate and parallel to its movement direction; the mesh belt substrate is woven, and the protrusions are woven into the mesh belt substrate or fixed on the surface of the mesh belt substrate; the spacing between two adjacent protrusions is 0.5~20mm, the width of the protrusion is 0.2~20mm, the height of the protrusion is 0.2~5mm, and the mesh number of the mesh belt substrate is 6-50 meshes.

2. A process for preparing the embossed dust-free paper according to claim 1, characterized in that: The method comprises the following steps: pressing stripes on a pre-pressed layer including one or more layers of dust-free paper raw materials before or after hot air drying, wherein the stripes are pressed by a mesh belt with protrusions.

3. The process for preparing embossed dust-free paper according to claim 2, characterized in that: The mesh belt with protrusions is wound around the surface of the pressure roller, and the protrusions of the mesh belt are in contact with the surface of the pre-pressed layer. The pressure of the pressure roller is 5~50 N / mm.

4. The process for preparing embossed dust-free paper according to claim 2, characterized in that: The temperature of hot air drying is set to 110~150℃.

5. A preparation process of a flow-guiding and absorbing integrated composite material, characterized in that: The steps include: S1: spreading one or more layers of absorbent layer raw materials layer by layer and pre-pressing them to form a pre-pressed layer; S2: Pressing the surface of the pre-pressed layer into stripes by a pressing roller with a mesh belt with protrusions on the surface, covering the surface of the pre-pressed layer with the guide layer material, and then sending it into a hot air drying device for drying and curing to obtain a composite layer; or S3: Covering the guide layer material on the surface of the pre-pressed layer and sending it into a hot air drying device for drying and curing, and then pressing the surface of the pre-pressed layer with stripes by a pressing roller with a mesh belt with protrusions wound on the surface to obtain a composite layer; S4: spraying water, drying, cooling and winding the composite layer to obtain a flow-guiding and absorbing integrated composite material; The mesh belt with protrusions includes a mesh belt base material and protrusions arranged on the surface of the mesh belt base material and parallel to its movement direction; the mesh belt base material is woven, and the protrusions are woven into the mesh belt base material or fixed on the surface of the mesh belt base material; the spacing between two adjacent protrusions is 0.5~20mm, the width of the protrusion is 0.2~20mm, the height of the protrusion is 0.2~5mm, and the mesh number of the mesh belt base material is 6-50 meshes.

6. The flow-guiding and absorbing integrated composite material prepared by the preparation process of claim 5 is characterized in that: The flow-guiding and absorbing integrally formed composite material is used for preparing disposable sanitary products.

7. The flow-guiding and absorbing integrated composite material according to claim 6, characterized in that: The disposable sanitary products include women's sanitary products, adult incontinence products, diapers, food mats, and pet mats.

8. A disposable sanitary product prepared using the embossed dust-free paper according to claim 1.

9. The disposable sanitary product according to claim 8, characterized in that: The disposable sanitary products include but are not limited to women's sanitary products, adult incontinence products, diapers, food mats, and pet mats.

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