CN113576764B

CN113576764B - Preparation method of sanitary product absorption core

Info

Publication number: CN113576764B
Application number: CN202111004771.4A
Authority: CN
Inventors: 吴晓彪; 邱光益; 林一速
Original assignee: Fujian Hengan Household Life Article Co Ltd
Current assignee: Fujian Hengan Household Life Article Co Ltd
Priority date: 2021-08-30
Filing date: 2021-08-30
Publication date: 2022-07-05
Anticipated expiration: 2041-08-30
Also published as: CN113576764A

Abstract

The invention discloses a preparation method of an absorption core body of a hygienic product, wherein the absorption core body is prepared by spraying an acrylate foaming material prepared by a high internal phase emulsion method on a working table; the acrylic ester foaming material is formed by mixing a first raw material and a second raw material; the absorption core body is formed by spraying and stacking layer by utilizing a spray head with the same width as the absorption core body in the depth direction; wherein, the proportion of the first raw material and the second raw material in the sprayed acrylic ester foam material is continuously adjusted, so that the pore diameter of each layer of the absorption core body is gradually reduced from the middle to two sides in the length direction; and increasing the vacuum degree provided by the working table surface layer by layer in the spraying process so as to gradually reduce the pore diameter of the foam pores of the absorption core body in the depth direction from bottom to top or from top to bottom.

Description

Preparation method of sanitary product absorption core

Technical Field

The invention relates to a preparation method of an absorption core body of a hygienic product.

Background

The acrylic ester foaming material prepared by the high internal phase emulsion method is widely applied to the absorption core body of sanitary products (sanitary towels and paper diapers).

However, the absorbent cores produced by the prior art have the following drawbacks: the absorbent core is generally of a single-layer or double-layer structure, the control of the contradiction relation between the absorption speed and the back-permeation quantity is poor, the cell sizes are consistent in the length direction, and the liquid is not favorably diffused to two sides.

Disclosure of Invention

In order to overcome the defects, the invention provides a preparation method of a novel sanitary product absorption core body.

In order to achieve the aim, the invention provides a preparation method of an absorption core body of a hygienic product, wherein the absorption core body is prepared by spraying an acrylate foaming material prepared by a high internal phase emulsion method on a working table; the acrylate foaming material is formed by mixing a first raw material and a second raw material; the absorption core body is formed by spraying and stacking a spray head with the same width as the absorption core body layer by layer in the depth direction;

wherein, the proportion of the first raw material and the second raw material in the sprayed acrylic ester foam material is continuously adjusted, so that the pore diameter of each layer of the absorption core body is gradually reduced from the middle to two sides in the length direction; and increasing the vacuum degree provided by the working table surface layer by layer in the spraying process so as to gradually reduce the pore diameter of the foam pores of the absorption core body in the depth direction from bottom to top or from top to bottom.

Further, the method specifically comprises the following steps:

21) reading a preset value table, wherein the preset value table records the continuous change value of the ratio of the first raw material to the second raw material in each layer of the acrylate foaming material of the absorption core body along the length direction of the core body, the initial spraying amount of the corresponding spray head, the thickness value of each layer of the absorption core body and the vacuum degree of each layer;

22) spraying layer by layer according to a preset value table, and providing a preset vacuum degree through a working table;

23) monitoring whether the thickness of the current-layer absorption core body exceeds a preset threshold value in real time:

if the amount of the absorption core is over, the next layer is sprayed after the spraying amount of the next layer of the absorption core is proportionally reduced or increased;

if not, spraying the next layer according to the preset spraying amount;

24) whether the current layer is the last layer or not, if not, returning to the step 22);

if the last layer is selected, detecting whether the thickness of the current absorption core body exceeds a preset threshold value;

if the spraying amount of the spray head of the first layer of the next absorption core in the preset value table is exceeded, the spraying amount of the spray head of the first layer of the next absorption core in the preset value table is proportionally reduced or increased, and a new preset value table is formed; returning to step 21);

if the spraying amount of the spray head of each layer of the current absorption core body is not exceeded, recording the spraying amount of the spray head of each layer of the current absorption core body to form a new preset value table; return to step 21).

Further, the method specifically comprises the following steps:

31) reading a preset value table, wherein the preset value table records the proportion of a first raw material and a second raw material in each layer of acrylate foaming material of the absorption core body, the initial spraying amount of a corresponding spray head, the thickness value of each layer of the absorption core body and the vacuum degree of each layer;

32) spraying layer by layer according to a preset value table, and providing a preset vacuum degree through a working table;

33) monitoring whether the thickness of the current-layer absorption core body exceeds a preset threshold value in real time:

if the spraying amount of the next layer of the absorption core body is exceeded, the next layer is sprayed after the spraying amount of the next layer of the absorption core body is proportionally reduced or increased;

if not, spraying the next layer according to the preset spraying amount;

34) whether the current layer is the last layer, if not, returning to the step 32);

if the spraying amount of the spray head of the first layer of the next absorption core in the preset value table is exceeded, the spraying amount of the spray head of the first layer of the next absorption core in the preset value table is proportionally reduced or increased, and a new preset value table is formed; returning to step 31);

if not: go to step 35);

35) detecting whether the weight of the current absorbent core exceeds a predetermined threshold;

if the weight of the current absorbing core body does not exceed the preset threshold value, recording the spraying amount of each layer of the current absorbing core body to form a new preset value table; returning to step 31);

if the weight of the current absorbing core body exceeds a preset threshold value, the mixing ratio and/or the spraying amount of the first raw material and the second raw material are increased or decreased according to a preset ratio, and a new preset value table is formed; returning to step 31.

The invention relates to a hygienic product, which comprises a surface layer and the absorption core body, wherein the surface layer is made of pure cotton non-woven fabric doped with 25-35% of moisture absorption fibers, and the moisture absorption fibers comprise a surface layer and a core layer; the skin layer is prepared from polyethylene, pore-forming materials and temperature-sensitive materials; the core layer is made of super absorbent resin or absorbent fibers;

wherein the micropores of the skin layer are in an open state at a temperature of above 33 ℃; the micropores of the skin layer are in a closed state at the temperature of below 33 ℃;

the moisture absorption fiber is prepared by adopting the following process:

70-90 parts of polyethylene, 0.5-3 parts of toughening agent, 1-5 parts of fluorine-containing acrylate resin, 0.5-3 parts of N-isopropyl acrylamide polymer and 10-30 parts of zinc oxide are mixed with 50-150 parts of core layer super absorbent resin material to prepare the moisture absorption fiber through spinning.

The pure cotton non-woven fabric needs to be subjected to after-treatment according to the following steps:

1) preparing an after-finishing agent;

2) adopting the prepared after-finishing agent to dip and prick the spunlace pure cotton non-woven fabric;

3) ionizing radiation grafting the soaked spunlace pure cotton non-woven fabric;

4) drying;

wherein the molecular formula of the after-finishing agent is as follows:

wherein R1 and R2 are higher fatty alcohol methacrylate ester or H, and the ester is cetyl ester or stearyl ester.

Adding trihydroxyethyl ethane, higher fatty alcohol methacrylate and fatty alcohol-polyoxyethylene ether into a composite emulsification system consisting of water, cetyl trimethyl ammonium bromide and tween 80, introducing nitrogen for protection, stirring at a constant temperature of 60-80 ℃, and adding an initiator (azodiisobutyronitrile and persulfate composite initiation system) to prepare the emulsion containing the system with the structural formula, wherein the emulsion contains polyhydric alcohol, higher fatty alcohol methacrylate water repellent groups and polyoxyethylene ether water repellent groups.

The absorption core body is formed by continuously spraying and stacking layer by layer in the depth direction by utilizing a spray head with the same width as the absorption core body, so that each layer of the absorption core body is continuous in the length direction; in the depth direction, in the continuous spraying process, due to the existence of vacuum provided by the working table, the pore diameter of each layer of absorption core body positioned below is larger than that positioned above; the ratio of the first raw material to the second raw material of the two adjacent layers of absorption cores and/or the vacuum degree corresponding to each layer of absorption core are adjusted, so that the pore diameter above the lower layer of absorption core in the two adjacent layers of absorption cores is the same as (or close to) the pore diameter below the upper layer of absorption core, and the interface between the two layers is eliminated; so that the aperture of the whole absorbing core body is gradually reduced from bottom to top along the depth direction.

Detailed Description

The invention aims to produce a multilayer absorption core body, wherein the absorption core body is prepared by spraying an acrylate foaming material prepared by a high internal phase emulsion method on a working table; the acrylic ester foaming material is formed by mixing a first raw material and a second raw material; the absorption core body is formed by spraying and stacking a spray head with the same width as the absorption core body layer by layer in the depth direction;

The vacuum degree can be provided by a negative pressure fan or a vacuum device.

The spray head is a controlled spray head and is used for continuously adjusting the proportion and the spraying amount of the first raw material and the second raw material in the sprayed acrylic ester foaming material; the controlled spray head and the working platform move relatively to complete the spraying of each layer, the controlled spray head can be fixed, and the working platform moves relatively to the controlled spray head continuously; or the working platform can be fixed, and the controlled spray head continuously moves relative to the working platform. The working platform can be a flat plate type platform and is driven to reciprocate by a reciprocating driving device; or a die wheel, which is driven to rotate by a rotating device to realize relative motion.

In the production process, a system containing a low emulsifier can be mixed with the emulsifier by a double-screw extrusion mode, and the proportion of the emulsifier in the length direction of the high internal phase emulsion can be continuously regulated and controlled by continuously regulating and controlling the mixing proportion of the first raw material and the second raw material; then a layer of absorbing core body can be formed on the working table surface by continuously spraying the absorbing core body with a spray head with the same width as the absorbing core body according to a preset proportion value at a constant speed. When the absorption core is stacked layer by layer in the depth direction, the pore diameter of each layer of absorption core body positioned below is larger than the pore diameter of each layer of absorption core body positioned above due to the existence of vacuum provided by the working table; the ratio of the first raw material to the second raw material of the two adjacent layers of absorption cores and/or the vacuum degree corresponding to each layer of absorption core are adjusted, so that the pore diameter above the lower layer of absorption core in the two adjacent layers of absorption cores is the same as (or close to) the pore diameter below the upper layer of absorption core, and the interface between the two layers is eliminated; the pore diameter of the whole absorbing core body is gradually reduced from bottom to top along the depth direction (when in actual use, the pores are large and close to the surface layer of the sanitary product); the absorption core body with the structure between layers manufactured by the method has the following advantages: the pore diameter of the pores on the two sides is small, the capillary action is strong, the liquid can be absorbed towards the two sides, and the utilization rate of the absorption core body on the sanitary product is improved. The pore diameter of the lower layer of the foam pore is large, so that the foam pore can realize quick liquid infiltration when being used as an upper layer of an absorption core body and has low reverse osmosis; the pore diameter of the lower layer pores is small, so that the liquid can be quickly infiltrated when the lower layer is used as an absorption core body, and the high liquid retention capacity can be realized by utilizing the capillary action.

The raw materials of the acrylic ester foaming material comprise acrylic ester, a cross-linking agent, an initiator, an emulsifier and salt.

Wherein the acrylate is one or two of isooctyl acrylate and isooctyl methacrylate.

The cross-linking agent is ethylene glycol dimethacrylate, the emulsifier is Tween 80, the salt is calcium chloride, and the initiator is an oxidation-reduction initiation system and can be sodium persulfate, potassium persulfate, ammonium persulfate and the like.

The acrylate, the cross-linking agent, the initiator, the emulsifier and the water are emulsified by an emulsifying kettle to obtain stable emulsion as a first raw material. The second raw material is emulsifier Tween 80.

Usually, the amount of the cross-linking agent is 20-65% (wt, mass fraction, the same below) of the amount of the monomer, the amount of the initiator is 0.5-5% of the reactant, the amount of the emulsifier is 4-16% of the reactant, the emulsion concentration, i.e., the ratio of the water phase to the oil phase, is 10: 1-36: 1, and the emulsification temperature is 60-80 ℃.

As a further development of the invention, the absorbent core is produced by spraying on a die wheel: the die wheel is provided with an air vent communicated with vacuum equipment; a layer of polytetrafluoroethylene breathable film is coated on the die wheel corresponding to the air holes; the absorption core body is sprayed on the polytetrafluoroethylene breathable film, so that the finished absorption core body is favorably taken off from the die wheel; the absorbing core body can be sprayed one layer each time the absorbing core body rotates one circle, and a plurality of spray heads can be arranged above the peripheral side of the die wheel, and each spray head is sprayed one layer; in the spraying process of each layer, the vacuum equipment provides vacuum with preset vacuum degree for each absorption core body; thus, the absorption core body can be adsorbed on the die wheel by utilizing vacuum, which is beneficial to production; and adjusting the degree of vacuum as required can affect the thickness of each layer of the absorbent core, the formation of pores, and the like. For example, since the absorption core is sprayed layer by layer, under the condition of a certain vacuum degree, the vacuum has the largest influence on the absorption core in the spraying process of the lowest layer, and the influence is smaller as the absorption core goes upwards; meanwhile, due to the fact that the effect of the fan force on the polytetrafluoroethylene air-permeable membrane is different in different depth directions, the emulsion closer to the polytetrafluoroethylene air-permeable membrane has larger air volume and larger pore-forming size, and the pore diameter from the bottom to the top is gradually reduced. By combining with layer-by-layer accumulation, the aperture can be continuously changed in the depth direction and the adjustable range is large.

Example 1

The invention discloses a preparation method of an absorption core body of a hygienic product, which comprises the following steps:

the absorption core body is prepared by spraying an acrylate foaming material prepared by a high internal phase emulsion method on a working table; the acrylic ester foaming material is formed by mixing a first raw material and a second raw material; the absorption core body is formed by spraying and stacking layer by utilizing a spray head with the same width as the absorption core body in the depth direction;

The method specifically comprises the following steps:

23) monitoring in real time whether the thickness of the current-layer absorption core body exceeds a preset threshold value:

if not, spraying the next layer according to the preset spraying amount;

if the spraying amount of the first layer of spray heads of the next absorption core in the preset value table is exceeded, the spraying amount of the first layer of spray heads of the next absorption core in the preset value table is proportionally reduced or increased, and a new preset value table is formed; returning to step 21);

if not, recording the spraying amount of each layer of the current absorption core body to form a new preset value table; return to step 21).

In this embodiment, the thickness of each layer is monitored to achieve product consistency.

Example 2

The embodiment is an improvement on the basis of embodiment 1, and the method specifically comprises the following steps:

31) reading a preset value table, wherein the preset value table records the continuous change value of the ratio of the first raw material to the second raw material in each layer of the acrylate foaming material of the absorption core body along the length direction of the core body, the initial spraying amount of the corresponding spray head, the thickness value of each layer of the absorption core body and the vacuum degree of each layer;

if not, spraying the next layer according to the preset spraying amount;

if the spraying amount of the first layer of spray heads of the next absorption core in the preset value table is exceeded, the spraying amount of the first layer of spray heads of the next absorption core in the preset value table is proportionally reduced or increased, and a new preset value table is formed; returning to step 31);

if not: go to step 35);

if the weight of the current absorption core body does not exceed the preset threshold value, recording the spraying amount of each layer of the current absorption core body to form a new preset value table; returning to step 31);

The weight of each absorbent core is taken into account in this embodiment. Considering that the foaming effect of the acrylic ester may be different due to different raw materials of each batch, the weight of the absorbent core is different under the condition of the same thickness of the absorbent core of different batches, and the consistency of the product is affected.

And (3) comparison test:

1. a sanitary napkin made of a foaming material is laid on a table, 10ml of pig blood is placed into the sanitary napkin by a pipette in alignment with a liquid adding point, timing is started, the time (namely, absorption time s) required after the absorption of the pig blood on the surface layer of the sanitary napkin is recorded, and the diffusion length (mm) of the blood on the surface layer is measured.

2. Weighing filter paper (diameter 110mm), and recording the weight of the filter paper as W1;

3. after 10min, a filter paper W1 with known weight is covered on the liquid adding point of the product, a 2.5kg briquetting (diameter 110mm) is placed, after 2min, the weight W2 of the filter paper is weighed, and the weight added by the filter paper (namely the rewet amount W) is calculated, and the formula is calculated: experimental results of W-W2-W1

Explanation of the phenomenon:

1. sample 1 has uniform pore diameter of small pores, and because the liquid is not easy to infiltrate downwards due to small pore diameter, the absorption time is long, but the capillary action of the small pores is strong, the liquid diffuses towards two sides, the diffusion length is longer, meanwhile, the strong capillary action has better liquid retention capacity, and the rewet capacity is lower.

2. The pore diameter of the big pore of the sample 2 is uniform, and the liquid quickly seeps downwards due to the large pore diameter, so the absorption speed is high, but the capillary action of the big pore is weak, the liquid is not easy to diffuse towards two sides, the diffusion length is short, and meanwhile, the liquid retention capacity is poor due to the weak capillary action, and the back seepage quantity is high.

3. The sample 3 has uniform cells in the length direction, large pore diameter of the upper layer of cells and small pore diameter of the lower layer of cells, and has the advantages and the disadvantages of the 1 st and the 2 nd, and each property is positioned in the middle of the two.

4. The pore diameter of the cells in the length direction of sample 4 is discontinuously reduced from the middle to both sides, the pore diameter of the upper layer of cells is large, the pore diameter of the lower layer of cells is small, the pore diameters of both sides are expected to be small, the pore diameter of the middle layer is large, and the liquid diffusion is improved, but the performance is poorer than that of sample 3, and presumably, the pore diameter of the cells in the length direction is discontinuous, so that an interface is formed, and the liquid diffusion and absorption are not facilitated.

5. Sample 5 length direction cell aperture reduces from the centre to both sides gradually, and upper strata cell aperture is big, and lower floor's cell aperture is little, for sample 3, 4, because the little capillary action on aperture on both sides is strong, the absorption rate is fast, and diffusion length is long, and the rewet volume is low.

6. In the invention, the pore diameter of the cells in the length direction of the sample 6 is gradually reduced from the middle to two sides, and the pore diameter of the cells in the depth direction is gradually reduced from top to bottom, so that a three-dimensional continuous absorption capillary diffusion effect is formed, and the absorption speed, the diffusion length and the rewet capacity are further improved relative to the performance of the sample 5.

The above embodiments can be applied to various types of diapers, sanitary napkins, etc., for example, the surface layer of the diaper is made of the above pure cotton nonwoven fabric.

The invention relates to a hygienic product, which comprises a surface layer and an absorption core body, wherein the surface layer is made of spunlace pure cotton non-woven fabric doped with 25-35% of moisture absorption fibers, and the moisture absorption fibers comprise a surface layer and a core layer; wherein, the skin layer is made of polyethylene, pore-forming material and temperature-sensitive material;

the core layer is made of super absorbent resin or absorbent fiber. Wherein, the micropores of the temperature sensitive material are in an open state at the temperature of more than 33 ℃; the micropores of the temperature-sensitive material are in a closed state at the temperature of below 33 ℃;

the moisture absorption fiber is prepared by adopting the following process:

The moisture absorption fiber adopts a skin-core structure, and the skin layer zinc oxide is separated from the polyethylene base material part when the skin-core structure fiber is prepared and drafted, so that micropores are generated. But when the temperature is lower than 33 ℃, the N-isopropyl acrylamide polymer extends to block micropores; can absorb less moisture in the air. And the N-isopropyl acrylamide polymer shrinks at the temperature of more than 33 ℃ to open the micropores, and the generated micropores only allow water vapor to permeate but not allow water molecules to permeate, so that the super absorbent resin in the core layer is prevented from being saturated by urine, but can absorb the water vapor. The absorbent fibers in the core layer can absorb moisture in the area surrounded by the paper diaper, so that the surface of the paper diaper is kept dry.

The spunlace pure cotton non-woven fabric is subjected to after-treatment according to the following steps:

1) preparing an after-finishing agent;

2) adopting the prepared after finishing agent to dip and prick the spunlace pure cotton non-woven fabric;

4) drying;

wherein the molecular formula of the after-finishing agent is as follows:

The after-finishing agent is prepared by adding trihydroxyethyl ethane, higher fatty alcohol methacrylate and fatty alcohol-polyoxyethylene ether into a composite emulsifying system consisting of water, hexadecyl trimethyl ammonium bromide and tween 80, introducing nitrogen for protection, stirring at a constant temperature of 60-80 ℃, and adding an initiator (azodiisobutyronitrile and persulfate composite initiation system) to prepare the emulsion containing the system with the structural formula, wherein the emulsion contains polyalcohol, higher fatty alcohol methacrylate water repellent groups and polyoxyethylene ether hydrophilic groups.

Through the treatment, the hydroxyl of the polyhydric alcohol and the cellulose is crosslinked and grafted, the hydroxyl end group is sealed, the hydrophilicity is reduced, and meanwhile, the water repellent group, namely the higher aliphatic acrylate or the siloxane acrylate, forms a net to cover the surface of the cellulose, so that the hydrophilicity of the fiber is further reduced. Meanwhile, the polyoxyethylene ether group realizes the hydrophilic performance of the material and realizes the unification of the infiltration and the rewet of the liquid. Ionizing radiation is used for assisting, so that the hydroxyl hydrogen bonds of the cellulose fibers are depolymerized by the ionizing radiation, the structure is loose, and the activity of the cellulose is increased; p-toluenesulfonic acid is used as a catalyst, ionizing radiation is used as an initiating system, and hydroxyl is dehydrated and condensed into ether, so that the finishing agent system is fixed on the cellulose fiber.

Claims

1. The preparation method of the sanitary product absorption core body is characterized in that the absorption core body is prepared by spraying an acrylate foaming material prepared by a high internal phase emulsion method on a working table; the acrylic ester foaming material is formed by mixing a first raw material and a second raw material; wherein, the first raw material is a system containing low emulsifier, and the second raw material is emulsifier; the absorbing core body is formed by spraying and stacking a spray head with the same width as the absorbing core body layer by layer in the depth direction;

wherein, the proportion of the first raw material and the second raw material in the sprayed acrylic ester foam material is continuously adjusted, so that the pore diameter of each layer of the absorption core body is gradually reduced from the middle to two sides in the length direction; and increasing the vacuum degree provided by the working table top layer by layer in the spraying process so as to gradually reduce the pore diameter of the foam pores of the absorption core body in the depth direction from bottom to top or from top to bottom;

the method specifically comprises the following steps:

1) reading a preset value table, wherein the preset value table records the proportion of a first raw material and a second raw material in each layer of acrylate foaming material of the absorption core body, the initial spraying amount of a corresponding spray head, the thickness value of each layer of the absorption core body and the vacuum degree of each layer;

2) spraying layer by layer according to a preset value table, and providing a preset vacuum degree through a working table;

3) monitoring whether the thickness of the current-layer absorption core body exceeds a preset threshold value in real time:

if not, spraying the next layer according to the preset spraying amount;

4) whether the current layer is the last layer or not, if not, returning to the step 2);

if the spraying amount of the spray head of the first layer of the next absorption core in the preset value table is exceeded, the spraying amount of the spray head of the first layer of the next absorption core in the preset value table is proportionally reduced or increased, and a new preset value table is formed; returning to the step 1);

if not: go to step 5);

5) detecting whether the weight of the current absorbent core exceeds a predetermined threshold;

if the weight of the current absorbing core body does not exceed the preset threshold value, recording the spraying amount of each layer of the current absorbing core body to form a new preset value table; returning to the step 1);

if the weight of the current absorbing core body exceeds a preset threshold value, the mixing ratio and/or the spraying amount of the first raw material and the second raw material are increased or decreased according to a preset ratio, and a new preset value table is formed; returning to the step 1;

the absorbent core is made by spraying on a die wheel: the die wheel is provided with an air vent communicated with vacuum equipment; a layer of polytetrafluoroethylene ventilated membrane is covered on the die wheel corresponding to the air holes; the absorption core body is sprayed on the polytetrafluoroethylene ventilated membrane; the absorption core body is sprayed one layer each time the absorption core body rotates one circle, or a plurality of spray heads are arranged above the peripheral side of the die wheel, and each spray head is sprayed one layer; during each layer spraying process, a vacuum apparatus supplies a vacuum of a predetermined degree to each absorbent core.