Water-absorbing antibacterial foaming sponge and preparation method thereof and insole

Abstract

The present invention relates to the technical field of shoe materials, and specifically discloses a water-absorbing antibacterial foaming sponge and a preparation method thereof and an insole, wherein the surface cloth of the insole is chemically bonded to the water-absorbing antibacterial foaming sponge, an aromatic primary amine group with a protective group is introduced into the molecular chain of the foaming sponge, and the surface of the water-absorbing antibacterial foaming sponge that is bonded to the surface cloth is surface-modified to obtain a diazotized group before bonding, and ultraviolet light is irradiated during bonding to cause the diazotized group to undergo a denitrification reaction with a carboxyl group. The present invention utilizes the antibacterial ability of citric acid chitosan to achieve excellent antibacterial performance and utilizes its rich hydrophilic groups to give the sponge good water absorption performance. On the one hand, the present invention undergoes a denitrification reaction with the surface carboxyl group of the plasma-treated surface cloth to chemically bond, so as to achieve a firm bonding without using hot melt adhesive or other adhesive materials, and on the other hand, undergoes a denitrification reaction with part of the carboxyl groups in the molecular chain of the foaming sponge to self-crosslink and realize a mesh structure, thereby ensuring the compression resistance of the foaming sponge and the insole.

Description

Technical Field

[0001] The invention relates to the technical field of shoe materials, and in particular to a water-absorbing antibacterial foaming sponge and a preparation method thereof, and an insole. Background Art

[0002] Polyurethane insoles are one of the commonly used insole materials in the prior art. The layer structure is generally composed of polyurethane sponge and surface cloth. PU hot melt adhesive is applied on the composite surface of polyurethane sponge and surface cloth, and polyurethane sponge is made by mixing and foaming a polyol component, an isocyanate component, a chain extension component and a catalytic component.

[0003] Polyurethane sponges are required to have certain hygroscopic and antibacterial properties in insole applications, and the general method is to mix a hydrophilic agent and / or an antibacterial agent into the polyurethane raw material in a blending manner. For example, the antibacterial polyurethane sponge disclosed in Chinese patent document CN114306709A can achieve hygroscopic and antibacterial effects, but the hydrophilic agent and the antibacterial agent are easy to precipitate and will cause the mechanical properties of the sponge to decrease. Summary of the invention

[0004] The purpose of the invention is to provide a water-absorbing and antibacterial foaming sponge and a preparation method thereof and an insole, which can impart good water absorption and moisture permeability, antibacterial properties and anti-compression properties, and can also be firmly combined with a surface cloth without using hot melt adhesive.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is:

[0006] The preparation method of the water-absorbing antibacterial foaming sponge specifically comprises the following steps:

[0007] S1. preparing a modifier: hydroxylating the sulfonic acid group in compound A by an alkali fusion method to obtain compound B having two hydroxyl groups and one aromatic primary amine group, and then introducing an Fmoc protecting group on the aromatic primary amine group by Fmoc-Cl to obtain compound C, and finally extracting with ethyl acetate, concentrating under reduced pressure to crystallize, filtering, and vacuum drying for later use;

[0008] The reaction route of compound C is as follows:

[0009] ;

[0010] S2, preparing a prepolymer: taking a diisocyanate component and the modifier of step S1 and mixing them in a molar ratio of 1.5-2:1, adding a catalyst, evacuating and passing nitrogen to react to obtain a prepolymerization product;

[0011] S3, mixing and foaming: 100 parts of citric acid chitosan, 10-20 parts of bio-based chain extender, 50-60 parts of prepolymerization product, 1-2 parts of silicone oil, and 3-6 parts of water are mixed under high pressure in a high pressure foaming machine, and then injected into a mold for foaming and molding, and then matured and cooled.

[0012] Preferably, the diisocyanate is petroleum-based isophorone diisocyanate or bio-based 1,4-butanediisocyanate.

[0013] Preferably, the catalyst is DBTDL.

[0014] Preferably, the bio-based chain extender is bio-based 1,3-propylene glycol or bio-based 1,4-butanediol.

[0015] Preferably, the molding temperature in step S3 is 60°C to 65°C.

[0016] Preferably, the hydroxylation in step S1 is carried out at a high temperature of 270° C. under normal pressure and with water vapor protection, so as to replace the sulfonic acid groups with hydroxyl groups.

[0017] Preferably, the method for introducing the Fmoc protecting group in step S1 is to dissolve compound B in THF solvent and add DIPEA and Fmoc-Cl.

[0018] The present invention also provides a water-absorbing and antibacterial foaming sponge prepared by the preparation method.

[0019] The present invention further provides an insole, comprising a face cloth and a water-absorbing antibacterial foam sponge, wherein the face cloth and the water-absorbing antibacterial foam sponge are chemically bonded, wherein the bonding surface of the face cloth that is bonded to the water-absorbing antibacterial foam sponge is plasma-treated before bonding to obtain carboxyl groups, and the bonding surface of the water-absorbing antibacterial foam sponge that is bonded to the face cloth is surface-modified before bonding to obtain diazotized groups, and during bonding, ultraviolet light is irradiated to cause a denitrification reaction between the diazotized groups and the carboxyl groups.

[0020] The surface modification process of the water-absorbing antibacterial foaming sponge is to first remove the Fmoc protecting group on the aromatic primary amine group using a deprotection solution, and then use a hydrochloric acid / sodium nitrite treatment solution to carry out a diazotization reaction in an ice bath.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The water-absorbing antibacterial foaming sponge of the present invention introduces citric acid chitosan into the molecular chain, utilizes the antibacterial ability of citric acid chitosan to achieve excellent antibacterial performance, and utilizes the rich hydrophilic groups of citric acid chitosan to give the sponge good water absorption performance; in addition, the present invention adopts a semi-prepolymer method to prepare the foaming sponge, and the prepolymer adopts a compound C having a hydroxyl group and an aromatic primary amine group with a protective group to transform the diisocyanate component, thereby introducing the aromatic primary amine group into the polyurethane molecular chain and inhibiting the aromatic primary amine group from participating in the reaction in the polyurethane synthetic foaming, and the Fmoc protective group is easy to remove, and when the insole is used, the foaming sponge does not need to be oxidized, but first undergoes a deprotection reaction and then a diazotization reaction, so that the foaming sponge has a diazotization component at the bonding surface, and the diazotization component can react with the surface carboxyl group of the plasma-treated face cloth under UV light to chemically bond, so that it can be firmly bonded without using hot melt adhesive or other adhesive materials, and on the other hand, it reacts with part of the carboxyl groups in the molecular chain of the foaming sponge to self-crosslink and realize a network structure, thereby ensuring the compression resistance of the foaming sponge and the insole.

[0023] Furthermore, the chain extension component and diisocyanate component of the present invention can be bio-based, with a high bio-based content, reducing dependence on non-renewable resources, and being environmentally friendly. The water-absorbing antibacterial foaming sponge of the present invention can also be used in the fields of sofas, soft beds, pillows, seats, underwear, etc. DETAILED DESCRIPTION Example 1

[0024] This embodiment provides an insole, including a face cloth and a water-absorbing antibacterial foam sponge, the face cloth and the water-absorbing antibacterial foam sponge are chemically bonded, and the mechanism of the chemical bonding is that the bonding surface of the face cloth that is bonded to the water-absorbing antibacterial foam sponge is plasma treated before bonding to obtain a carboxyl group, and the bonding surface of the water-absorbing antibacterial foam sponge that is bonded to the face cloth is surface-modified before bonding to obtain a diazotized group, and ultraviolet light is used during bonding to cause a denitrification reaction between the diazotized group and the carboxyl group. The reaction mechanism is as follows:

[0025]

[0026] Wherein: the surface cloth is made of polyester fabric, and its plasma treatment process is: the plasma gas is oxygen, the power frequency is 40KHz, the power is 100W, and the treatment time is 5 minutes.

[0027] The surface modification process of the water-absorbing antibacterial foaming sponge is as follows: cutting the sponge block according to the size of the insole, immersing the sponge block in a prepared piperidine / DMF deprotection solution, and reacting with nitrogen for 20 minutes to remove the Fmoc protecting group on the aromatic primary amine group; taking out, washing, and drying, and then immersing the sponge block in a prepared hydrochloric acid / sodium nitrite treatment solution, and causing a diazotization reaction in an ice bath at 5°C.

[0028] The UV light conditions were: UV lamp 15W, distance 10cm, irradiation for 30min, and during the irradiation process, the surface cloth and the water-absorbent antibacterial foam sponge were kept lightly pressed.

[0029] The water-absorbing antibacterial foaming sponge of this embodiment uses a chemical modification method to introduce a primary aromatic amine with a protective group into the molecular chain. The protective group is used to inhibit the reaction between the isocyanate group and the aromatic amine group so that the isocyanate group reacts with the hydroxyl group of the compound C to form a polyurethane prepolymer.

[0030] The preparation method of the water-absorbing antibacterial foaming sponge in this embodiment specifically comprises the following steps:

[0031] S1. Preparation of modifier: using alkali fusion method, the alkali solution is 80% caustic soda solution, at normal pressure and high temperature of 270°C and passing water vapor to protect the sulfonic acid group in compound A to hydroxylate, to obtain compound B with two hydroxyl groups and one aromatic primary amine group, then dissolving compound B in tetrahydrofuran THF solvent and adding N,N-diisopropylethylamine DIPEA and fluorenylmethoxycarbonyl chloride Fmoc-Cl, the volume ratio of Fmoc-Cl to compound B is 1:2, the molar ratio of DIPEA to compound B is 6:1, introducing Fmoc protecting group on the aromatic primary amine group to obtain compound C, finally extracting with ethyl acetate, concentrating under reduced pressure to crystallize, filtering, vacuum drying for standby use. The reaction route is as follows:

[0032]

[0033] S2. Preparing a prepolymer: taking bio-based 1,4-butanediisocyanate and the modifier of step S1 in a molar ratio of 1.5:1, mixing them in ethyl acetate, adding 100 ppm of catalyst dibutyltin dilaurate DBTDL, evacuating and passing nitrogen at 80° C. to obtain a prepolymerization product.

[0034] S3, mixing and foaming: 100 parts of citric acid chitosan, 20 parts of bio-based 1,3-propylene glycol, 60 parts of prepolymerization product, 2 parts of silicone oil and 5 parts of water are mixed under high pressure in a high pressure foaming machine, and then injected into a mold for foaming at 60°C, and matured and cooled.

[0035] The test results of the water absorption and moisture permeability of the water-absorbing antibacterial foam sponge in this embodiment are as follows:

[0036]

[0037] The test results of the antibacterial properties of the water-absorbing antibacterial foaming sponge in this embodiment are as follows:

[0038]

[0039] Note: The control sample is 100% pure cotton cloth; F: growth value F of the control sample (F= gCt-lgC0); G: growth value G of the test sample (G=lgTt-LgT0); A*: antibacterial activity value A (A=FG); the sterilization method of the test sample is high-pressure steam sterilization (121℃, 15min); the culture time of the test sample after inoculation of the bacterial solution is 24 hours; the detection counting method is the plate counting method.

[0040] lgCt: The average of the common logarithms of the bacterial counts on three control samples 24 hours after inoculation with the test strain.

[0041] lgC0: The average of the common logarithms of the bacterial counts on three control samples at 0 hours after inoculation with the test strain.

[0042] lgTt: The average of the common logarithms of the bacterial counts on three test samples 24 hours after inoculation with the test strain.

[0043] LgT0: The average of the common logarithms of the bacterial counts on the three test samples at 0 hours after inoculation of the test bacteria.

[0044] In addition, according to ASTM D395:2003, the compression performance of the insole of this embodiment is less than 15%, and the peeling strength between the surface cloth and the water-absorbing antibacterial foam sponge also meets the requirements.

[0045] Example 2

[0046] This embodiment provides a method for preparing a water-absorbing antibacterial foam sponge, which specifically includes the following steps:

[0047] S1. Preparation of modifier: using alkali fusion method, the alkali solution is 80% caustic soda solution, at normal pressure and high temperature of 270°C and passing water vapor to protect the sulfonic acid group in compound A to hydroxylate, to obtain compound B having two hydroxyl groups and one aromatic primary amine group, then dissolving compound B in tetrahydrofuran THF solvent and adding N,N-diisopropylethylamine DIPEA and fluorenylmethoxycarbonyl chloride Fmoc-Cl, the volume ratio of Fmoc-Cl to compound B is 1:2, the molar ratio of DIPEA to compound B is 6:1, introducing Fmoc protecting group on the aromatic primary amine group to obtain compound C, finally extracting with ethyl acetate, concentrating under reduced pressure to crystallize, filtering, and vacuum drying for use.

[0048] S2, preparing a prepolymer: petroleum-based isophorone diisocyanate and the modifier of step S1 are mixed in ethyl acetate at a molar ratio of 2:1, 100 ppm of catalyst dibutyltin dilaurate DBTDL is added, and the mixture is reacted at 80° C. under vacuum and nitrogen flow to obtain a prepolymerization product.

[0049] S3, mixing and foaming: 100 parts of citric chitosan, 15 parts of bio-based 1,4-butanediol, 55 parts of prepolymerization product, 1.5 parts of silicone oil and 4 parts of water are mixed under high pressure in a high pressure foaming machine, and then injected into a mold for foaming at 65°C, and matured and cooled.

[0050] After testing, the water-absorbing and antibacterial foamed sponge of Example 2 also has the same level of water absorption, moisture permeability and antibacterial performance as Example 1, the surface cloth of the insole cannot be peeled off, and the compression performance is less than 15%.

[0051] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention shall be defined by the attached claims and their equivalents.

Claims

1. An insole, characterized in that: The invention comprises a face cloth and a water-absorbing antibacterial foam sponge, wherein the face cloth and the water-absorbing antibacterial foam sponge are chemically bonded, wherein the bonding surface of the face cloth that is bonded to the water-absorbing antibacterial foam sponge is subjected to plasma treatment to obtain carboxyl groups before bonding, and the bonding surface of the water-absorbing antibacterial foam sponge that is bonded to the face cloth is surface-modified to obtain diazotized groups before bonding, and ultraviolet light is used to cause a denitrification reaction between the diazotized groups and the carboxyl groups during bonding; The surface modification process of the water-absorbing antibacterial foaming sponge is to first remove the Fmoc protecting group on the aromatic primary amine group using a deprotection solution, and then use a hydrochloric acid / sodium nitrite treatment solution to carry out a diazotization reaction in an ice bath; The method for preparing the water-absorbing antibacterial foaming sponge specifically comprises the following steps: S1. preparing a modifier: hydroxylating the sulfonic acid group in compound A by an alkali fusion method to obtain compound B having two hydroxyl groups and one aromatic primary amine group, and then introducing an Fmoc protecting group on the aromatic primary amine group by Fmoc-Cl to obtain compound C, and finally extracting with ethyl acetate, concentrating under reduced pressure to crystallize, filtering, and vacuum drying for later use; The reaction route of compound C is as follows: ； S2, preparing a prepolymer: taking a diisocyanate component and the modifier of step S1 and mixing them in a molar ratio of 1.5-2:1, adding a catalyst, evacuating and passing nitrogen to react to obtain a prepolymerization product; S3, mixing and foaming: 100 parts of citric acid chitosan, 10-20 parts of bio-based chain extender, 50-60 parts of prepolymerization product, 1-2 parts of silicone oil, and 3-6 parts of water are mixed under high pressure in a high pressure foaming machine, and then injected into a mold for foaming and molding, and then matured and cooled.

2. The insole according to claim 1, characterized in that: The diisocyanate is petroleum-based isophorone diisocyanate or bio-based 1,4-butanediisocyanate.

3. The insole according to claim 1, characterized in that: The catalyst is DBTDL.

4. The insole according to claim 1, characterized in that: The bio-based chain extender is bio-based 1,3-propylene glycol or bio-based 1,4-butanediol.

5. The insole according to claim 1, characterized in that: The molding temperature in step S3 is 60°C to 65°C.

6. The insole according to claim 1, characterized in that: The hydroxylation in step S1 is carried out at a high temperature of 270° C. under normal pressure and with water vapor protection, so as to replace the sulfonic acid group with a hydroxyl group.

7. The insole according to claim 1, characterized in that: The method for introducing the Fmoc protecting group in step S1 is to dissolve compound B in THF solvent and add DIPEA and Fmoc-Cl.

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