Three-dimensional embossed non-woven fabric containing cotton layer and preparation method thereof
Technical Field
The invention relates to a non-woven fabric and a manufacturing method thereof, in particular to a three-dimensional embossed cotton-containing layer non-woven fabric which can be used for a surface layer of an absorbent product and a preparation method thereof.
Background
At present, a large number of non-woven fabrics are applied to the surface layers of sanitary absorption articles such as sanitary towels, sanitary pads, paper diapers and the like. Mainly comprises hot air non-woven fabric, hot rolling non-woven fabric and spun-bonded non-woven fabric. When the nonwoven fabric is used as a top sheet of an absorbent article, it is required to be in close contact with the human body, and therefore, the nonwoven fabric is required to be soft, breathable and skin-friendly. Although the existing hot air non-woven fabric, hot rolled non-woven fabric and spun-bonded non-woven fabric are soft in hand feeling, compared with the spunlace non-woven fabric, the spunlace non-woven fabric is softer and more skin-friendly, and the touch feeling of cotton fabrics is better brought to people.
The known production process of non-woven fabric comprises the following steps: when the hot-air non-woven fabric is produced, part of cotton fibers are added in a fiber-separating link or a cotton-carding link, and then the integrated cotton-containing surface layer is manufactured by netting and cloth formation after secondary combing; the further improvement is realized by double-layer carding, namely, the lower ES fiber layer is formed on the net by using the traditional production process, a cotton fiber layer is added on the lower ES fiber layer, and then the cotton fiber layer and the ES fibers are fixed into a whole by a spunlace process. Although the cotton-containing nonwoven fabric has improved skin touch and softness and acceptable penetration rate, the reverse penetration (moisture regain) during use is high, which is caused by the inherent characteristics of the cotton fiber, and although the hydrophilic treatment of the ES fiber itself is still required to be further improved.
As for the improvement of the non-woven fabric technology in the current hygienic product industry, the following problems exist:
1. based on the rapid rise of the existing labor cost, the spoke width of a non-woven fabric production line is increased, and the linear velocity of the production line is also increased; the line speed of a diaper or sanitary napkin manufacturing line using a nonwoven fabric is increased, and the cost of the related materials is also increased (in addition to SAP);
2. the non-woven fabric development needs to change the production process, including the change of equipment structure, the change of process, the change of diaper equipment and the change of diaper production process;
for the reasons mentioned above, the diaper production line has 500 sheets per minute, and the cost of one sheet is 0.7 yuan, so the cost of developing non-woven fabrics (and other materials are the same) is very high, the material cost is 10.5 ten thousand yuan per 5 hours of starting up the machine in one day, no water, electricity, gas and labor cost are contained, and the equipment transformation cost is not included, so that any small change to the material part is a matter of moving the whole body in a short time. As for the subsequent small-scale trial production, medium-scale setup and debugging, the cost required to be invested is larger. Also for cost reasons, the problems of the cotton-containing nonwoven fabric itself have not been solved well.
Disclosure of Invention
The invention provides a three-dimensional embossed non-woven fabric with a cotton-containing layer and a preparation method thereof, aiming at solving the problem of high reverse osmosis of the non-woven fabric with cotton in the prior art, and mainly solving the contradiction between the skin touch feeling and the reverse osmosis of the non-woven fabric with cotton.
The technical scheme adopted by the invention for solving the technical problems is as follows: a method for preparing three-dimensional embossed non-woven fabric containing cotton layers comprises the following steps:
a. preparing ES fibers, carding the ES fibers after opening the ES fibers to form a web to obtain an ES fiber layer, wherein the square gram weight of the ES fiber layer is 15-25 g/m2The linear density of the ES fiber is 2.0 dtex-2.3 dtex;
b. b, preparing a cotton fiber layer, namely carding cotton fibers containing 0.05 to 0.10 percent of water-repellent oil agent by a carding machine, and then flatly paving the cotton fibers on the upper surface of the ES fiber layer prepared in the step a at intervals, wherein the paving area of the cotton fiber layer accounts for 30 to 70 percent of the area of the ES fiber layer; the square gram weight of the cotton fiber layer is 10-25 g/m2The linear density of the cotton fiber is 1.8 dtex-2.2 dtex;
c. b, reinforcing the two fiber layers in the step b through hot air or a spunlace process, so that the cotton fiber layer is fixed on the upper surface of the ES fiber layer;
d. b, embossing and reinforcing the cotton fiber layer treated in the step c, wherein the embossing area accounts for 15% -30% of the area of the cotton fiber layer;
the preparation of the ES fiber in the step a comprises the following steps:
a1, preparing an ES fiber filament according to the preparation steps of the known ES fiber;
a2, oiling the tows in the step 1 by an oiling roller, wherein the oiling agent is a mixture of polyether silicone oil and isomeric alcohol ether, the weight ratio of the polyether silicone oil to the isomeric alcohol ether is 5:1, and the oiling rate is controlled to be 0.2-0.25%;
a3, winding, bundling and drafting the tows oiled in the step a 2;
a4, performing secondary oiling treatment on the filament bundle obtained in the step a3 through a second oiling roller, wherein the oiling oil agent is a mixture of polyether silicone oil and citric acid, the weight ratio of the polyether silicone oil to the citric acid is 5:1, and the oiling rate is controlled to be 0.3% -0.4%;
a5, drying the tows oiled twice in the step a4, wherein the drying temperature is 125-135 ℃;
a6, cutting the dried tows in the step a5 into fibers of 38 +/-3 mm, and performing compression packaging on the fibers to complete the preparation of the ES fibers.
The further improvement is that: in the step b of the preparation method of the three-dimensional embossed cotton-layer-containing non-woven fabric, the cotton fiber layer is formed by paving a plurality of cotton fiber units on the upper surface of the ES fiber layer side by side along the conveying direction of the ES fiber layer, the distance between every two adjacent cotton fiber units is 10-30 mm along the transverse direction of the ES fiber layer, and the transverse width of each cotton fiber unit is 10-30 mm.
The further improvement is that: in the step b of the preparation method of the three-dimensional embossed cotton-layer-containing non-woven fabric, the cotton fiber layer is formed by flatly paving a plurality of cotton fiber units on the upper surface of the ES fiber layer in a grid arrangement mode, and the paving area of the cotton fiber layer accounts for 60-70% of the area of the ES fiber layer.
The further improvement is that: in the step b of the preparation method of the three-dimensional embossed cotton-layer-containing non-woven fabric, the ratio of the conveying speed of the cotton fiber layer to the conveying speed of the ES fiber layer is 0.95-0.97.
The invention also provides three-dimensional embossed non-woven fabric with a cotton layer based on the preparation method, which comprises an ES fiber layer and a cotton fiber layer fixedly arranged above the ES fiber layer through hot air or spunlace, wherein the cotton fiber layer contains 0.05-0.10% of water-repellent oiling agent, the cotton fiber layer is formed by flatly laying a plurality of cotton fiber units on the upper surface of the ES fiber layer side by side along the longitudinal direction of the ES fiber layer, the distance between two adjacent cotton fiber units is 10-30 mm along the transverse direction of the ES fiber layer, the transverse width of each cotton fiber unit is 10-30 mm, the laying area of the cotton fiber layer accounts for 30-70% of the area of the ES fiber layer, and the square gram weight of the cotton fiber layer is 10-25 g/m2The linear density of the cotton fiber is 1.8dtex to 2.2dtex, and the square gram weight of the ES fiber layer is 15g/m to 25g/m2The linear density of the ES fiber is 2.0 dtex-2.3 dtex, the cotton fiber layer and the ES fiber layer below the cotton fiber layer are provided with embossments, the area of the embossments accounts for 15% -30% of the area of the cotton fiber layer, and the ES fiber contains a mixture of polyether silicone oil, isomeric alcohol ether and citric acid.
Preferably, the three-dimensionally embossed cotton layer-containing nonwoven fabric has different embossing depths in the cotton fiber layer in a direction perpendicular to the thickness of the cotton fiber layer to form three-dimensionally embossed patterns.
By adopting the technical scheme, the invention has the beneficial effects that:
1. cotton fibers are in contradiction with respect to skin touch and reverse osmosis, ES fibers are in contradiction with respect to skin touch and hydrophilicity, and the problem that the superposition of two fibers needs to be solved and considered is more, and in most cases, theoretical or laboratory technical solutions are feasible, but no enterprise or unit is willing to provide a verification channel, because the cost is too high, and experimental conditions or verification channels cannot be provided for all technical solutions even for enterprises with larger scales. The invention is one of 10 problems in 2019, and the proposed guiding ideas for solving the problems are as follows: on one hand, the cotton fiber is subjected to hydrophobic treatment while the chance of contacting liquid is reduced under the condition of keeping the skin touch feeling of the cotton fiber; on the other hand, the hydrophilicity of the ES fibers is improved under the condition of improving the skin touch feeling of the ES fibers, and meanwhile, the area ratio of the cotton fibers to the ES fibers is optimized; and the ES fiber uses different blending hydrophilic oil agents in the pre-spinning and the post-spinning. The test result of the infiltration speed of the non-woven fabric prepared by the method is within 2S, the infiltration speed is expressed in the rapid absorption of the skin side and the rapid absorption of liquid remained in cotton fibers, the effect is really unexpected, a quality inspection part person independently peels and weighs the composite fiber layer after liquid absorption to find that the weight difference with the conventional fiber layer is obvious, meanwhile, the reverse osmosis amount of the composite fiber layer is not more than 0.15g, and the reverse osmosis amount of the prior paper diaper made of cotton fiber fabric is generally more than 0.5 g. The inventor simultaneously tests the reverse osmosis amount of the composite of the ES fiber after common hydrophilic treatment and the cotton fiber layer, and the effect is improved, but the effect of the reverse osmosis of the cotton layer-containing non-woven fabric prepared by the preparation method cannot be achieved.
2. The further improvement of the invention is based on the long-term working experience of the inventor, in the preparation method process, the ratio of the conveying speed of the cotton fiber layer to the conveying speed of the ES fiber layer is set to be 0.95-0.97, the speed difference is that for the composite fiber layer subjected to the subsequent spunlace treatment, the fabric is flat and has no crease, especially for the non-woven fabric production line which is only subjected to one oven, the number of the subsequent finishing rollers can be reduced by half, and the corresponding energy consumption can be reduced by more than 10%.
Drawings
FIG. 1a is a front view of a three-dimensional embossed nonwoven fabric containing a cotton layer according to one embodiment of the present invention;
FIG. 1b is a front view of a three-dimensional embossed nonwoven fabric containing a cotton layer according to a second embodiment of the present invention;
FIG. 2 is a transverse cross-sectional view (before embossing) of FIG. 1 a;
in the figure: 1 and 1' are cotton fiber layers; 2 and 2' are layers of ES fibers;
Detailed Description
The following detailed description will be provided for the embodiments of the present invention with reference to specific embodiments, so that how to apply the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented.
Unless otherwise indicated, the technical means employed in the examples are conventional and well known to those skilled in the art, and the reagents and starting materials employed are also commercially available, and the source, trade name and if necessary the constituents of the reagents used are indicated at the first appearance.
Example one
Referring to fig. 1a and 2, a method for preparing a three-dimensional embossed cotton layer-containing non-woven fabric comprises the following steps:
a. preparing ES fibers and carding to form a web, wherein the step is realized through two production links:
as a well-known ES fiber production process, it includes: polyethylene/polypropylene melt spinning, oiling, winding, bundling, drawing, oiling, curling, drying, shearing and packaging.
The preparation process of the ES fiber of the embodiment comprises the following steps:
a1, preparing ES fiber filaments by melt spinning polyethylene and polypropylene according to the known ES fiber preparation steps;
a2, oiling the fiber filament bundle obtained in the step 1 by an oiling roller, wherein the oiling agent is a mixture of polyether silicone oil and isomeric alcohol ether, the weight ratio of the polyether silicone oil to the isomeric alcohol ether is 5:1, and the oiling rate is controlled to be 0.2-0.25% (oil rate measured by drying after oiling);
a3, winding, bundling and drafting the tows oiled in the step a 2;
a4, performing secondary oiling treatment on the tows in the step a3 by using a second oiling roller, wherein the oiling agent is a mixture of polyether silicone oil and citric acid, the weight ratio of the polyether silicone oil to the citric acid is 5:1, and the oiling rate is controlled to be 0.3% -0.4% (the total oiling rate measured by drying after secondary oiling);
the oil agent in the step a2 and the step a4 is prepared into 3.5 weight percent of working solution by distilled water in the production process, oiling is carried out (the weight ratio of the oil agent to the working solution is referred to), a proper amount of propylene glycol can be added for assisting dissolution if necessary, and the polyether silicone oil can be produced by Japan shiner company according to the linear velocity and the environmental temperature.
a5, drying the tow subjected to secondary oiling in the step a4, wherein the drying temperature is 130 ℃;
a6, cutting the dried tows in the step a5 into fibers of 38 +/-3 mm, wherein the linear density of the ES fibers is required to be 2.0 dtex-2.3 dtex, and performing compression packaging on the fibers to complete the preparation of the ES fibers.
The back-end workshop is used for carding and forming non-woven fabrics for ES fibers, and comprises the following components: rough opening, fine opening, carding and forming a net, spunlace curing, drying, finishing, slitting, reeling and packaging.
The rear-stage workshop in the embodiment specifically comprises the following steps: the method comprises the steps of carrying out rough opening, fine opening and carding on an ES fiber board to form a net to obtain an ES fiber layer, and controlling the fiber throwing speed to enable the square gram weight of the ES fiber layer to be 15-25 g/m2In this embodiment, the control is at 20g/m2。
b. Preparing a cotton fiber layer, adopting a known cotton fiber production process, controlling the linear density to be 1.8 dtex-2.2 dtex, adding a water-repellent oiling agent into cotton fibers in a later process in an atomizing spraying or rolling oiling mode, then drying to ensure that the content of the water-repellent oiling agent of the dried cotton fibers is 0.05-0.10% (weight ratio), wherein the step is generally implemented by an upstream supplier, the adopted water-repellent oiling agent is mixed by long-chain alkyl pyridine quaternary ammonium salt and a fluorine compound (3M company) according to the weight ratio of 3:1 for water-repellent blending treatment, and the later section adopts three-section drying treatment, and the step mainly comprises the step of uniformly performing water-repellent treatment on the cotton fibers.
B, removing the package of the cotton fiber board subjected to the water repellency treatment in a non-woven fabric production workshop, carding the cotton fiber board by a carding machine, and paving the cotton fiber board on the upper surface of the ES fiber layer 2 prepared in the step a at intervals by a mesh belt, wherein the square gram weight of the cotton fiber layer 1 is 15g/m2Here, the spaced tiling is such that: the cotton fiber layer 1 is formed by paving five cotton fiber units on the upper surface of the ES fiber layer 2 side by side along the conveying direction of the ES fiber layer 2, the distance between every two adjacent cotton fiber units is 30mm along the transverse direction of the ES fiber layer 2, the transverse width of each cotton fiber unit is 30mm, meanwhile, a certain width is reserved at the outermost side of the ES fiber layer for facilitating subsequent treatment, and in the implementation, the paving area of the cotton fiber layer 1 accounts for 45.5% of the area of the ES fiber layer 2; meanwhile, the ratio of the conveying speed of the fiber layer 1 to the conveying speed of the ES fiber layer 2 is controlled to be 0.97, namely the rotating speed of a roller and a cylinder of the ES fiber layer carding machine is higher than that of a cotton fiber layer carding machine.
c. B, reinforcing the two fiber layers in the step b through a known spunlace process, so that the cotton fiber layer 1 is fixed on the upper surface of the ES fiber layer 2;
d. and c, embossing and reinforcing the cotton fiber layer 1 treated in the step c, wherein the embossing area accounts for 15% of the area of the cotton fiber layer, embossing male dies on the outer circumferential side surface of the embossing roller used in the step have different sizes along the radial direction of the embossing roller, the sizes are shown in the way that the embossed cotton fiber layer 1 is perpendicular to the thickness direction of the cotton fiber layer, the embossing has different embossing depths on the cotton fiber layer 1, and the embossing roller and a corresponding bottom roller are heated to 65 ℃ during embossing.
Referring to fig. 1a and 2, the three-dimensional embossed cotton-containing layer prepared based on the production method is free ofThe woven cloth has the following technical characteristics: this non-woven fabrics sets firmly cotton fiber layer 1 in its top including the ES fibrous layer 2 of range upon range of setting and through water thorn, cotton fiber layer 1 contains the water finish of refusing of 0.05% ~ 0.10% (cotton fiber raw materials throw-in link survey) to cotton fiber layer 1 comprises at the upper surface of ES fibrous layer 1 by five cotton fiber unit flats side by side along the longitudinal direction of ES fibrous layer 2, along the transverse direction of ES fibrous layer 2, and the distance between two adjacent cotton fiber unit is 30mm, each the transverse width of cotton fiber unit is 30mm, cotton fiber layer lays the area and accounts for 45.5% of ES fibrous layer area, the square grammes per square of cotton fiber layer is 15g/m2The linear density of the cotton fiber is 1.8dtex to 2.2dtex, and the square gram weight of the ES fiber layer 2 is 20g/m2The linear density of the ES fiber is 2.0dtex to 2.3dtex, the cotton fiber layer 1 and the ES fiber layer 2 below the cotton fiber layer are provided with embossments, the embossed area accounts for 15 percent of the area of the cotton fiber layer, and the ES fiber contains a mixture of polyether silicone oil, isomeric alcohol ether and citric acid (the mixture is measured after the drying of the mixture in the oiling link of pre-spinning and post-spinning of the ES fiber).
Based on the stability of production equipment and the difficulty of process control, the related indexes cannot be accurately controlled, for example, the linear density, the square gram weight and the content of the water-repellent oil agent or the hydrophilic oil agent are more and can only be represented by one numerical range.
Example two: in view of the fact that the three-dimensional embossed cotton-containing layer nonwoven fabric is applied to the surface layer material of a diaper or a sanitary napkin, the second embodiment provides a method for preparing a three-dimensional embossed cotton-containing layer nonwoven fabric with a more friendly skin-friendly effect, which is different from the first embodiment in that:
referring to fig. 1b, in step b, the cotton fiber layer 1 'is composed of a plurality of cotton fiber units laid on the upper surface of the ES fiber layer 2' in a grid arrangement, the cotton fiber layer 1 'has a laying area of 65% of the area of the ES fiber layer 2', the web forming process greatly sacrifices the speed of a non-woven fabric production line, and under the same process conditions, the power consumption is increased by more than 20% compared with the first embodiment, but the skin-friendly feeling of the three-dimensional embossed non-woven fabric is obviously improved compared with the first embodiment, when the diaper sample manufactured by the inventor is used for blindness, the users with more than nine times of the diaper sample think that the fabric touch feeling of the second embodiment is better than that of the first embodiment, while the amount of reverse osmosis did not significantly deteriorate relative to example one, it further indicates that the absorption of the liquid retained by the upper cotton fibers after hydrophilic treatment of the ES fiber layer is very significant.
The present invention relates to various material or process parameters, such as the linear density of cotton or ES fibers, which are generally averaged in practice as a batch of raw material, the linear density of which is controlled within a set range to ensure skin-friendly properties, and which cannot be, and does not necessarily need to be, 1.8dtex, or individually higher than 2.3 dtex. The content of the water-repellent oil agent of the cotton fiber layer is a measured value after the cotton fiber is oiled and dried, the content fluctuation of the cotton fiber layer is large, and the cotton fiber layer is suitable for batch detection, so that the content range is large; the area ratio of the cotton fiber layer to the ES fiber layer is relatively flexible, tests are carried out on 75% of the area ratio of the cotton fiber layer to the ES fiber layer, the beneficial effects of the invention can be achieved integrally, based on the consideration of cost, the cotton fiber layer and the ES fiber layer tend to adopt smaller square gram weight, so that the cost is favorably controlled, but the corresponding skin touch feeling is also reduced, and the adjustment can be flexibly carried out according to the product selling price. The oiling rates of the ES fibers in the fore spinning and the after spinning are measured after drying, and due to uncertainty of filament bundle swing and oil outlet of an oil groove in an oiling roller, the corresponding oiling rate can only be controlled in one range, and the oiling rate is convenient to operate and can be realized in each limited range.
The above description is only an embodiment utilizing the technical content of the present disclosure, and any modification and variation made by those skilled in the art can be covered by the claims of the present disclosure, and not limited to the embodiments disclosed.