CN118022035B

CN118022035B - Memory core and preparation method and application thereof

Info

Publication number: CN118022035B
Application number: CN202410118652.9A
Authority: CN
Inventors: 李敬
Original assignee: Guangdong Meideng New Material Technology Co ltd
Current assignee: Guangdong Meideng New Material Technology Co ltd
Priority date: 2024-01-29
Filing date: 2024-01-29
Publication date: 2024-09-13
Anticipated expiration: 2044-01-29
Also published as: CN118022035A

Abstract

The application discloses a memory core, a preparation method and application thereof, and belongs to the field of absorbent cores. The memory core is prepared by thermally bonding the following raw materials in parts by weight: 10-30 parts of wood pulp fiber; 20-100 parts of water-absorbent resin; 3-15 parts of composite fiber; the composite fiber comprises a core layer and a surface layer, wherein the core layer and the surface layer are both made of polymer materials, and the melting point of the polymer materials of the core layer is higher than that of the polymer materials of the surface layer. The application has the advantages of improving the elasticity of the absorbent core and improving the comfort when wearing the absorbent core.

Description

Memory core and preparation method and application thereof

Technical Field

The application relates to the field of absorption cores, in particular to a memory core, a preparation method and application thereof.

Background

Absorbent cores are commonly used in sanitary products, such as diapers and napkins, and have the functions of absorbing and storing liquid, and therefore the position in sanitary products is extremely important.

The classification of the absorption cores comprises wood pulp cores and composite cores, wherein the wood pulp cores consist of wood pulp fibers and water-absorbent resin and are characterized by rapid liquid absorption, but have the defect of easy lump formation; the composite core body is formed by laminating water-absorbent resin by adopting a plurality of layers of non-woven fabrics together with hot melt adhesive, and the non-woven fabrics limit the movement of the water-absorbent resin, so that the composite core body is smooth and is not easy to stick together.

However, due to the non-woven fabrics and the hot melt adhesive, the composite core body is hard in overall texture and lacks elasticity, so that the core body cannot recover the shape in time after being extruded, and the experience of a user when wearing the sanitary product is reduced.

Disclosure of Invention

In order to improve the elasticity of the absorbent core and improve the comfort of wearing the absorbent core, the application provides a memory core and a preparation method and application thereof.

In a first aspect, the present application provides a memory core, which adopts the following technical scheme:

The memory core is prepared by thermally bonding the following raw materials in parts by weight:

10-30 parts of wood pulp fiber;

20-100 parts of water-absorbent resin;

3-15 parts of composite fiber;

The composite fiber comprises a core layer and a surface layer, wherein the core layer and the surface layer are both composed of polymer materials, and the melting point of the polymer materials of the core layer is higher than that of the polymer materials of the surface layer.

Through adopting above-mentioned technical scheme, utilize the characteristic of composite fiber's top layer low melting point, at the in-process of thermal bonding, the partial melting softening of top layer produces the adhesion force, make composite fiber interweave with wood pulp fiber and form network structure, the high melting point characteristic of sandwich layer provides intensity and stability for this network structure, and composite fiber interweaves with wood pulp fiber also forms the surrounding and supports to the water-absorbent resin that disperses in network structure, improve water-absorbent resin's dispersion stability, effectively reduce the water-absorbent resin and agglomerate, stick together the possibility when guaranteeing the liquid absorption ability of core, thereby improve the planarization of core. In addition, because the structure is stable, a nonwoven fabric and other nonwoven materials are not needed to be used as the basis of the core body, the structure formed by the wood pulp fiber, the water-absorbent resin and the composite fiber has higher elasticity, so that the core body can quickly recover the original shape after being extruded, and the deformation recovery function similar to that of a memory sponge is obtained, namely the memory core body is obtained.

Optionally, the core layer is made of polypropylene material or polyester material, and the surface layer is made of polyethylene material.

By adopting the technical scheme, the polypropylene and the polyester have higher strength and higher melting point than the polyethylene, so the polypropylene and the polyester are suitable for being used as core layer materials, the polyethylene has lower melting point and is suitable for being partially melted and softened in the thermal bonding process, and the connection bonding between the composite fibers, the wood pulp fibers and the water absorbent resin are realized.

Optionally, the wood pulp fiber is modified wood pulp fiber, the modified wood pulp fiber is pretreated by an epoxy silane coupling agent and a vinyl silane coupling agent, then acrylonitrile and isoprene are copolymerized and grafted, and then polyamine compound is grafted, so that the modified wood pulp fiber is obtained.

By adopting the technical scheme, the epoxy functional group and the vinyl functional group are connected to the surface of the wood pulp fiber by the pretreatment of the epoxy silane coupling agent and the vinyl silane coupling agent, wherein the vinyl functional group can provide an access basis for the copolymerization grafting of acrylonitrile and isoprene, so that the copolymer of acrylonitrile and isoprene is grafted to the surface of the wood pulp fiber, and the copolymerization structure of acrylonitrile and isoprene is similar to the polyolefin structure of the composite fiber, so that the compatibility of the wood pulp fiber and the composite fiber is improved, and the dispersibility and the bonding effect are better; the epoxy functional group can provide an access basis for grafting the polyamine compound, and the polyamine can form functional group bonding with the water absorbent resin, so that the wood pulp fiber, the water absorbent resin and the composite fiber form a core with higher strength, the diversion channel in the core is more stable, and the liquid absorption capability is also improved due to the improvement of the connection stability of the wood pulp fiber and the water absorbent resin.

Optionally, the mass ratio of the wood pulp fiber to the epoxy silane coupling agent to the vinyl silane coupling agent to the acrylonitrile to the isoprene to the polyamine compound is 10 (0.5-1) (0.15-0.3) (0.2-0.4) (0.18-0.3).

By adopting the technical scheme, the addition proportion of the epoxy silane coupling agent, the vinyl silane coupling agent, the acrylonitrile, the isoprene and the polyamine compound is controlled, and the surface grafting state of the wood pulp fiber is regulated, so that the wood pulp fiber is better combined with the composite fiber and the water-absorbent resin.

Optionally, the polyamine compound is one or two of butanediamine and hexanediamine.

By adopting the technical scheme, the butanediamine and the hexanediamine have longer carbon chains, so that the bonding structure of the wood pulp fiber and the water-absorbent resin is more reasonable, the flow of liquid in the core body is promoted, and the liquid storage capacity is improved.

Optionally, the water absorbent resin is an acrylic acid type water absorbent resin.

By adopting the technical scheme, the acrylic acid in the water-absorbent resin and the polyamine compound in the wood pulp fiber form bonding, so that the connection stability of the wood pulp fiber and the water-absorbent resin is improved.

In a second aspect, the present application provides a method for preparing a memory core, which adopts the following technical scheme:

a preparation method of a memory core body comprises the following steps:

Mixing wood pulp fiber and composite fiber, scattering, air-laying, adding water-absorbent resin in the air-laying process to form fiber web, then heat-bonding and reinforcing, compacting, and cooling to obtain the memory core.

By adopting the technical scheme, the air-laid mode ensures that the wood pulp fibers and the composite fibers are uniformly dispersed, so that the water-absorbent resin can be ensured to have good dispersibility after being added, and the flatness and elasticity of the core body are improved.

Optionally, the thermal bonding is performed by hot air penetration, and the temperature of the hot air is 120-140 ℃.

By adopting the technical scheme, the hot air penetrating mode promotes the composite fiber to be heated uniformly, and the composite fiber is better melted and softened, so that the adhesive force is generated, and the stable fiber net is formed.

Optionally, prior to mixing the wood pulp fibers and the composite fibers, further comprising comminuting and opening the wood pulp fibers and opening the composite fibers.

By adopting the technical scheme, the aggregation of wood pulp fibers and composite fibers is reduced, and the wood pulp fibers and the composite fibers are promoted to be uniformly mixed.

Optionally, the step of forming the web is provided a plurality of times, the latter step being performed on the web-bearing surface formed by the previous step.

By adopting the technical scheme, the fiber webs are laid layer by layer, which is beneficial to improving the dispersibility of the water-absorbent resin in the core body.

Optionally, the preparation method of the modified wood pulp fiber comprises the following steps:

dispersing wood pulp fiber in a first solvent, adding an epoxy silane coupling agent and a vinyl silane coupling agent, heating for reaction, and filtering after the reaction is finished to obtain first wood pulp fiber;

Dispersing the first wood pulp fiber in a second solvent, adding acrylonitrile and isoprene, heating, slowly adding an initiator, continuing to react after the addition is finished, and filtering after the reaction is finished to obtain second wood pulp fiber;

Dispersing the second wood pulp fiber in a third solvent, adding a polyamine compound, heating for reaction, and filtering after the reaction is finished to obtain the modified wood pulp fiber.

In a third aspect, the application provides an application of a memory core, including applications in paper diapers, sanitary napkins, breast-feeding and breast-absorbing napkins, sweat-absorbing napkins and kitchen papers.

In summary, the application has the following beneficial effects:

1. according to the application, the characteristic of low melting point of the surface layer of the composite fiber is utilized, in the process of thermal bonding, the surface layer part is melted and softened to generate adhesive force, so that the composite fiber and the wood pulp fiber are interwoven to form a network structure, the composite fiber and the wood pulp fiber are interwoven to form a surrounding and supporting structure for the water-absorbent resin dispersed in the network structure, the dispersion stability of the water-absorbent resin is improved, the liquid absorption capacity of the core body is ensured, and meanwhile, the aggregation and lump formation possibility of the water-absorbent resin is effectively reduced, so that the flatness of the core body is improved. In addition, because the structure is stable, a nonwoven fabric and other nonwoven materials are not needed to be used as the basis of the core body, the structure formed by the wood pulp fiber, the water-absorbent resin and the composite fiber has higher elasticity, so that the core body can quickly recover the original shape after being extruded, and the deformation recovery function similar to that of a memory sponge is obtained, namely the memory core body is obtained.

2. The application also adopts modified wood pulp fiber, improves the compatibility of the wood pulp fiber and the composite fiber and improves the bonding capability of the wood pulp fiber and the water-absorbent resin, so that the wood pulp fiber, the water-absorbent resin and the composite fiber form a core body with higher strength, the flow guide channel in the core body is more stable, and the liquid absorption capability is also improved because the connection stability of the wood pulp fiber and the water-absorbent resin is improved.

Detailed Description

The present application will be described in further detail below.

Preparation example 1

A method for preparing a modified wood pulp fiber comprising the steps of:

1kg of wood pulp fiber, 0.05kg of an epoxy silane coupling agent, 0.05kg of a vinyl silane coupling agent, 0.015kg of acrylonitrile, 0.02kg of isoprene, and 0.018kg of a polyamine compound were weighed. Wherein the epoxy silane coupling agent is KH-560, the vinyl silane coupling agent is KH-570, and the polyamine compound is butanediamine.

An initiator solution was additionally prepared, the initiator solution comprising 2g benzoyl peroxide and 500mL toluene.

Dispersing wood pulp fiber in 7L of 80wt% ethanol solution, adding epoxy silane coupling agent and vinyl silane coupling agent, heating to 65 ℃ for reaction for 1.5h, and filtering after the reaction is finished to obtain first wood pulp fiber;

Dispersing the first wood pulp fiber in 7L of toluene, adding acrylonitrile and isoprene, heating to 95 ℃, slowly dripping an initiator solution, continuing to react for 2 hours after the addition, and filtering after the reaction is finished to obtain a second wood pulp fiber;

dispersing the second wood pulp fiber in 5L of 50wt% ethanol solution, adding 50g of sodium carbonate, uniformly stirring, adding a polyamine compound, heating to 55 ℃ for reaction for 3 hours, and filtering after the reaction is finished to obtain the modified wood pulp fiber.

Preparation example 2

A method for preparing a modified wood pulp fiber comprising the steps of:

the difference between this preparation and preparation 1 is the different amounts of the preparation materials.

1Kg of wood pulp fiber, 0.1kg of epoxy silane coupling agent, 0.1kg of vinyl silane coupling agent, 0.03kg of acrylonitrile, 0.04kg of isoprene, and 0.03kg of polyamine compound were weighed. Wherein the epoxy silane coupling agent is KH-560, the vinyl silane coupling agent is KH-570, and the polyamine compound is hexamethylenediamine.

Preparation example 3

A method for preparing a modified wood pulp fiber comprising the steps of:

the difference between this preparation and preparation 2 is that the polyamine compound was used in an amount of 0.015kg, and ethylenediamine was used as the polyamine compound.

Preparation example 4

A method for preparing a modified wood pulp fiber comprising the steps of:

1kg of wood pulp fiber, 0.057kg of aminosilane coupling agent, 0.05kg of vinylsilane coupling agent, 0.015kg of acrylonitrile and 0.02kg of isoprene were weighed. Wherein the amino group is KH-550, and the vinyl silane coupling agent is KH-570.

Dispersing wood pulp fiber in 7L of 80wt% ethanol solution, adding an aminosilane coupling agent and a vinyl silane coupling agent, heating to 65 ℃ for reaction for 1.5h, and filtering after the reaction is finished to obtain first wood pulp fiber;

dispersing the first wood pulp fiber in 7L of toluene, adding acrylonitrile and isoprene, heating to 95 ℃, slowly dripping an initiator solution, continuing to react for 2 hours after the addition, and filtering after the reaction is finished to obtain the modified wood pulp fiber.

Preparation example 5

A method for preparing a modified wood pulp fiber comprising the steps of:

1kg of wood pulp fiber, 0.05kg of an epoxy silane coupling agent, and 0.018kg of a polyamine compound were weighed. Wherein the epoxy silane coupling agent is KH-560, and the polyamine compound is hexamethylenediamine.

Dispersing wood pulp fiber in 7L of 80wt% ethanol solution, adding epoxy silane coupling agent, heating to 65 ℃ for reaction for 1.5h, and filtering after the reaction is finished to obtain first wood pulp fiber;

dispersing the first wood pulp fiber in 5L of 50wt% ethanol solution, adding 50g of sodium carbonate, uniformly stirring, adding a polyamine compound, heating to 55 ℃ for reaction for 3 hours, and filtering after the reaction is finished to obtain the modified wood pulp fiber.

Preparation example 6

A method for preparing a modified wood pulp fiber comprising the steps of:

This preparation differs from preparation 2 in that in the preparation of the second wood pulp fiber, no acrylonitrile was added, but instead 0.058kg of styrene was added.

Example 1

The preparation method of the memory core body comprises the following steps:

crushing and opening wood pulp fibers, and opening composite fibers, wherein the wood pulp fibers are needle-leaved wood fibers with the length of 2.5mm; the composite fiber adopts ES fiber, the core layer of the composite fiber is polypropylene, the surface layer of the composite fiber is polyethylene, the fineness of the composite fiber is 2D, and the length is 8mm.

The wood pulp fiber and the composite fiber are mixed, enter a forming box for scattering and are in a floating state, and reach a net curtain under the action of air flow to obtain a coarse fiber net.

The forming boxes are provided with a plurality of, after the former forming box forms a coarse fiber web, the coarse fiber web enters the latter forming box, and a resin blanking device is arranged between the adjacent forming boxes, the resin blanking device is used for sowing water absorbent resin, the water absorbent resin is acrylic acid type macromolecule water absorbent resin, the water absorbent resin is purchased from Chunhui macromolecule material company, the water absorbent resin is sown to the coarse fiber web to form the fiber web, then the next fiber web is continuously formed on the bearing surface of the fiber web, and in the embodiment, the forming boxes are provided with three. The mass ratio of the wood pulp fiber, the water absorbent resin and the composite fiber is 10:20:3.

And (3) the formed fiber web enters a hot air box, is subjected to thermal bonding reinforcement in a hot air penetrating mode, and is compacted by a compacting roller, cooled and wound to obtain the memory core body at the hot air temperature of 120 ℃.

Example 2

The preparation method of the memory core body comprises the following steps:

this example differs from example 1 in that the mass ratio of wood pulp fibers, water absorbent resin and composite fibers used was 30:100:15.

Example 3

The preparation method of the memory core body comprises the following steps:

This example differs from example 1 in that the mass ratio of wood pulp fibers, water absorbent resin and composite fibers used was 20:50:7.

Examples 4 to 9

Examples 4 to 9 differ from example 1 in that the wood pulp fibers were modified wood pulp fibers, the sources of which are shown in Table 1.

TABLE 1

	Modified wood pulp fiber source
		Example 4	Preparation example 1
Example 5	Preparation example 2
		Example 6	Preparation example 3
Example 7	Preparation example 4
		Example 8	Preparation example 5
Example 9	Preparation example 6

Comparative example 1

The preparation method of the memory core body comprises the following steps:

this comparative example differs from example 1 in that no conjugate fiber was added.

Comparative example 2

The commercial composite core body adopts a dust-free paper-high polymer resin-non-woven fabric-high polymer resin-dust-free paper structure, and hot melt adhesive is sprayed between the dust-free paper and the high polymer resin.

Performance testing

With reference to GB/T24442.1-2009 "determination of compression Property of textiles", the compression elastic rate of the core was tested, wherein the compression elastic rate was 10s at a light pressure of 0.02kPa, 60s at a heavy pressure of 1kPa, and the recovery time was 60s, and the test results are shown in Table 2.

Taking 100mL of physiological saline (the mass concentration is 0.9%) and heating to 40 ℃, then adding the physiological saline into a core body, placing an absorption core body sample into a RH test box with the temperature of 40+/-1 ℃ and the concentration of 65+/-1% for 10min, and then taking out the absorption core body sample for testing; the tester holds the two ends of the sample of the absorbent core with two hands respectively, and first, the tester swings one end of the sample of the absorbent core with one hand, repeats 10 times, then the two hands repeatedly stretch the two ends of the sample of the absorbent core for 10 times, then the two hands rub the core, repeat 10 times, finally, observe whether the phenomenon of piling up occurs on the absorbent core, and record the result of the phenomenon in table 2.

Referring to QB/T5650-2021, composite absorbent core for Disposable paper sanitary products, the absorption rate, absorption speed and rewet amount of the core were tested, physiological saline, simulated menstrual blood and milk were used as test solutions, respectively, and test results were recorded in Table 3.

TABLE 2

	Modulus of elasticity under compression (%)	Lump formation phenomenon
			Example 1	88	No lump
Example 2	90	No lump
			Example 3	87	No lump
Example 4	86	No lump
			Example 5	85	No lump
Example 6	85	No lump
			Example 7	86	No lump
Example 8	85	No lump
			Example 9	85	No lump
Comparative example 1	83	Lump
			Comparative example 2	67	No lump

TABLE 3 Table 3

As can be seen from table 2, compared with the conventional composite core of nonwoven fabric-water absorbent resin and the wood pulp core of wood pulp fiber-water absorbent resin, the memory core composed of wood pulp fiber-water absorbent resin-composite fiber has the advantages of no lump formation and high compression elasticity, i.e., stable structure and high elasticity and comfort.

With the analysis of table 3, the memory core composed of wood pulp fiber, water-absorbent resin and composite fiber has higher absorption rate, faster absorption speed and smaller rewet amount for normal saline, simulated menstrual blood and milk, so the memory core has good liquid absorption and liquid storage capacity for various use scenes, and can be applied to the fields of paper diapers, sanitary napkins, breast-feeding and milk-absorbing napkins, sweat-absorbing napkins, kitchen papers and the like.

It can be seen that the modified wood pulp fiber can exert better liquid-absorbing and liquid-storing effects when the test solution is prepared from the simulated menstrual blood and milk which are difficult to absorb, as compared with the test solutions of the examples 4-5, and the obvious liquid-absorbing and liquid-storing effects are also obtained.

In comparison with example 6 in combination with example 5, it can be seen that long chain polyamine compounds such as hexamethylenediamine have a better modifying effect than ethylenediamine as polyamine compound to modify wood pulp fibers; compared with the embodiment 7, the embodiment 5 is combined, and compared with the embodiment 7, the embodiment has the advantages that the epoxy silane coupling agent is firstly used for grafting the wood pulp fiber, and then the hexamethylenediamine is connected with the epoxy group in a reaction way to realize the grafting, so that the modification effect of the wood pulp fiber and the liquid absorption and storage effect of the final core body are better improved.

By combining example 5 with examples 8-9, it can be seen that the wood pulp fibers are modified to incorporate the acrylonitrile-isoprene copolymer, which helps to improve the compatibility of the wood pulp fibers with the composite fibers, thereby promoting higher stability of the web forming the core, and more stable flow guide channels in the core, and further improving the liquid absorption and storage capacity of the core.

The present embodiment is merely illustrative of the present application and not limiting, and one skilled in the art, after having read the present specification, may make modifications to the embodiment without creative contribution as required, but is protected by patent law within the scope of the claims of the present application.

Claims

1. A memory core, characterized by: the adhesive is prepared by thermally bonding the following raw materials in parts by weight:

10-30 parts of wood pulp fiber;

20-100 parts of water-absorbent resin;

3-15 parts of composite fiber;

the composite fiber comprises a core layer and a surface layer, wherein the core layer and the surface layer are both composed of polymer materials, and the melting point of the polymer materials of the core layer is higher than that of the polymer materials of the surface layer;

The wood pulp fiber is modified wood pulp fiber, the modified wood pulp fiber is pretreated by an epoxy silane coupling agent and a vinyl silane coupling agent, then acrylonitrile and isoprene are copolymerized and grafted, and then polyamine compound is grafted, so that the modified wood pulp fiber is obtained.

2. A memory core according to claim 1, wherein: the core layer is made of polypropylene material or polyester material, and the surface layer is made of polyethylene material.

3. A memory core according to claim 1, wherein: the mass ratio of the wood pulp fiber to the epoxy silane coupling agent to the vinyl silane coupling agent to the acrylonitrile to the isoprene and polyamine compound is 10 (0.5-1) (0.15-0.3) (0.2-0.4) (0.18-0.3).

4. A memory core according to claim 1, wherein: the polyamine compound is one or two of butanediamine and hexanediamine.

5. A memory core according to claim 1, wherein: the water-absorbent resin is acrylic acid type water-absorbent resin.

6. A method for manufacturing a memory core according to any one of claims 1 to 5, characterized in that: the method comprises the following steps:

7. The method for manufacturing a memory core according to claim 6, wherein: the thermal bonding adopts a hot air penetrating mode.

8. The method for manufacturing a memory core according to claim 6, wherein: the preparation method of the modified wood pulp fiber comprises the following steps:

9. Use of a memory core according to any of claims 1-5, characterized in that: including applications in diapers, sanitary napkins, breast-feeding and absorbent napkins, sweat-absorbing napkins and kitchen papers.