Children picture book environment-friendly glue based on natural plant extracts as well as preparation method and application of children picture book environment-friendly glue

Abstract

The invention relates to the technical field of adhesives, in particular to child picture book environment-friendly glue based on natural plant extracts and a preparation method and application of the child picture book environment-friendly glue. The loofah sponge facial mask is prepared from the following components in parts by weight: 10 to 15 parts of loofah sponge extract, 45 to 55 parts of dynamic network base liquid, 0.5 to 1.5 parts of xanthan gum, 1.2 to 2.3 parts of nano cellulose, 0.3 to 0.6 part of methyl cellulose, 2 to 4 parts of aloe vera gel, 1 to 2 parts of glycerol, 2 to 4 parts of sorbitol and 0.3 to 0.7 part of rosemary extract, wherein the dynamic network base solution is obtained by mixing oxidized konjac glucomannan, silk fibroin, tannic acid and ferric chloride. A dynamic multi-cross-linked network design is adopted, dynamic covalent bonds are formed through oxidized konjac glucomannan and silk fibroin, and a three-dimensional network with the synergistic effect of the dynamic covalent bonds and coordination bonds is constructed by combining tannic acid-Fe coordination complexation.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and in particular, to an environment-friendly glue for children's picture books based on natural plant extracts, its preparation method and application. Background Art

[0002] Publication No. CN1944560A discloses a glue for an environment-friendly pressure-sensitive adhesive composite material and its preparation method. Through the optimization of the formula, appropriate components and ratios are selected to greatly improve its performance. Its components include octyl ester, butyl ester, acrylic acid, ethyl hydroxyacetate, vinyl acetate, ammonium persulfate, ammonium bicarbonate, etc. The initial tack and holding tack of this glue are stable, the peeling performance is good, there is no pungent smell, and the environmental protection performance is good. However, the glue protected by the above patent document, like traditional synthetic glues, contains harmful substances such as volatile organic compounds (VOCs) and formaldehyde, and there are health and environmental pollution risks in long-term use. In recent years, with the improvement of environmental protection and health awareness, natural plant extracts (such as guar gum, locust bean gum, sesbania gum) have become a research hotspot again due to their non-toxic and biodegradable characteristics. Through modern extraction and modification technologies, plant-based glues have optimized their performance while retaining their environmental protection advantages. However, existing environment-friendly glues for children's picture books are prone to brittle fracture during children's use due to the shear force generated by frequent page turning, which leads to a decrease in bonding strength. In view of this, we propose an environment-friendly glue for children's picture books based on natural plant extracts, its preparation method and application. Summary of the Invention

[0003] The purpose of the present invention is to provide an environment-friendly glue for children's picture books based on natural plant extracts, its preparation method and application, so as to solve the problems raised in the above background art.

[0004] To achieve the above purpose, the present invention provides an environment-friendly glue for children's picture books based on natural plant extracts, which includes the following components: 10-15 parts by weight of loofah sponge extract, 45-55 parts by weight of dynamic network base liquid, 0.5-1.5 parts by weight of xanthan gum, 1.2-2.3 parts by weight of nanocellulose, 0.3-0.6 parts by weight of methylcellulose, 2-4 parts by weight of aloe vera gel, 1-2 parts by weight of glycerol, 2-4 parts by weight of sorbitol, and 0.3-0.7 parts by weight of rosemary extract; Among them, the dynamic network base liquid is obtained by mixing oxidized konjac glucomannan, silk fibroin, tannic acid and ferric chloride.

[0005] Introduce oxidized konjac glucomannan, silk fibroin, tannic acid and ferric chloride to form a dynamic network. Since oxidized konjac glucomannan has aldehyde groups and carboxyl groups, the aldehyde groups form Schiff base (-CH=N-) structures with the amino groups in silk fibroin. This reaction is a kind of dynamic covalent bond with certain reversibility. At the same time, the carboxyl groups of oxidized konjac glucomannan can form chemical bonding with iron ions in ferric chloride, and multiple ortho-phenolic hydroxyl groups of tannic acid can act as ligands to complex with iron ions to form a dynamic coordination network. Therefore, silk fibroin serves as a cross-linking carrier, the complex of tannic acid and iron ions, and oxidized konjac glucomannan serves as cross-linking and bridging, integrating dynamic covalent bonds and dynamic coordination bonds, achieving multiple cross-linkings, jointly promoting the formation of a complex dynamic three-dimensional network, adapting to the repeated opening and closing during the use of children's picture books, and extending the service life.

[0006] Preferably, the specific preparation steps of the loofah extract are as follows: Mechanically crush the dried loofah to a particle size of 0.5 - 1 mm, degrease it with 70 - 75% ethanol at 60 - 65 °C for 2 - 3 h to obtain degreased loofah. Mix the degreased loofah with 2 - 3 mol / L NaOH solution at a mass ratio of 1:13 - 15, reflux at 85 - 90 °C for 3 - 4 h, centrifuge and separate. Reflux the supernatant with acetic acid and hydrochloric acid with a volume ratio of 9:1 at 70 - 75 °C for 2 - 3 h. Wash the precipitate until neutral, freeze-dry, and react with sodium sulfite at 120 - 125 °C for 2 - 3 h to obtain the loofah extract.

[0007] Since the adhesiveness of oxidized konjac glucomannan is weaker than that of traditional glue substrates, loofah extract is added to further make up for the initial adhesive strength. Moreover, the loofah extract has the ability to coordinate with Fe³⁺, which can enhance the stability of the dynamic cross-linking network.

[0008] Preferably, the mass ratio of the precipitate to sodium sulfite is 1:0.3 - 0.5.

[0009] Preferably, the preparation method of the dynamic network base liquid is as follows: Dissolve oxidized konjac glucomannan in deionized water to obtain an oxidized konjac glucomannan solution. After adding silk fibroin to the oxidized konjac glucomannan solution, adjust the pH to 8.5 - 9.0, stir at 40 - 50 °C for 1 - 2 h, then add tannic acid and stir to mix evenly. Dropwise add 0.5 - 1 mol / L ferric chloride solution and stir at room temperature for 20 - 30 min to obtain the dynamic network base liquid; use inductively coupled plasma mass spectrometry to detect the Fe³⁺ residue, remove the Fe³⁺ residue and ensure that the final free Fe³⁺ residue does not exceed 70 mg / kg to ensure that the glue meets the safety standards for children's products.

[0010] Preferably, the mass fraction of the oxidized konjac glucomannan solution is 5 - 8%.

[0011] Preferably, the mass ratio of the oxidized konjac glucomannan to the fibroin is 1:0.3 - 0.5.

[0012] Preferably, the mass ratio of the oxidized konjac glucomannan to the tannic acid is 1:0.1 - 0.2.

[0013] Preferably, the molar ratio of the tannic acid to the ferric chloride is 2 - 4:1.

[0014] On the other hand, the present invention provides a preparation method of an environment-friendly glue for children's picture books based on natural plant extracts, which is used to prepare the above-mentioned environment-friendly glue for children's picture books based on natural plant extracts, and comprises the following steps: Mix the dynamic network base liquid with the loofah extract, homogenize at a high speed of 8000 - 9000 rpm at 60 °C for 15 - 20 min, successively add xanthan gum, nanocellulose and methyl cellulose, stir at 40 - 45 °C until there are no particles, add glycerol, aloe vera gel, sorbitol and rosemary extract, adjust the pH to 6.5 - 7.5, carry out vacuum homogenization at -0.08 MPa for 25 - 30 min to remove bubbles, and fill and seal after passing through a 200-mesh sieve to obtain an environment-friendly glue for children's picture books based on natural plant extracts.

[0015] The present invention also provides an application of the environment-friendly glue for children's picture books based on natural plant extracts, including the environment-friendly glue for children's picture books based on natural plant extracts prepared by the preparation method of the environment-friendly glue for children's picture books based on natural plant extracts as described above. This environment-friendly glue for children's picture books based on natural plant extracts is applied to the bonding of picture books and paper materials.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: In the environment-friendly glue for children's picture books based on natural plant extracts, its preparation method and application, a dynamic multiple cross-linked network design is adopted. Through the formation of dynamic covalent bonds between oxidized konjac glucomannan and fibroin, combined with the tannic acid-Fe³⁺ coordination complexation, a three-dimensional network with the synergistic action of dynamic covalent bonds and coordination bonds is constructed. This structure has both reversibility and stability, endowing the glue with self-healing ability to adapt to the use scenario of the picture book being repeatedly opened and closed. The loofah extract is used to retain phenolic hydroxyl groups and introduce sulfonic acid groups, which not only enhance the stability of the dynamic network through Fe³⁺ coordination but also make up for the insufficient initial bonding strength of oxidized konjac glucomannan, realizing performance complementarity. The use of plant-derived components such as loofah, aloe vera gel, and rosemary extract avoids harmful substances such as formaldehyde and benzene series in traditional glues and meets the safety standards for children's products. Specific embodiments

[0017] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0018] The children's picture book environmental protection glue based on natural plant extracts of the present invention comprises the following components: 10-15 parts by weight of loofah sponge extract, 45-55 parts by weight of dynamic network base liquid, 0.5-1.5 parts by weight of xanthan gum, 1.2-2.3 parts by weight of nanocellulose, 0.3-0.6 parts by weight of methylcellulose, 2-4 parts by weight of aloe vera gel, 1-2 parts by weight of glycerol, 2-4 parts by weight of sorbitol, and 0.3-0.7 parts by weight of rosemary extract; Among them, the dynamic network base liquid is obtained by mixing oxidized konjac glucomannan, silk fibroin, tannic acid and ferric chloride; The main active ingredients in the rosemary extract include terpene compounds (monoterpenes, sesquiterpenes, diterpenes), phenolic acid compounds (rosmarinic acid and its derivatives), flavonoid compounds (luteolin and its glycosides, apigenin), and volatile oils (α-pinene, β-pinene).

[0019] Example 1: The children's picture book environmental protection glue based on natural plant extracts, its preparation method and application, comprising the following steps: Prepare the components: 10 parts by weight of loofah sponge extract, 45 parts by weight of dynamic network base liquid, 1.5 parts by weight of xanthan gum, 2.3 parts by weight of nanocellulose, 0.6 parts by weight of methylcellulose, 4 parts by weight of aloe vera gel, 2 parts by weight of glycerol, 4 parts by weight of sorbitol, and 0.7 parts by weight of rosemary extract; Among them, the dynamic network base liquid is obtained by mixing oxidized konjac glucomannan, silk fibroin, tannic acid and ferric chloride; Mechanically crush the dry loofah sponge to a particle size of 0.5 mm, degrease it with 70% ethanol at 60 °C for 2 h to obtain degreased loofah sponge. Mix the degreased loofah sponge with 2 mol / L NaOH solution at a mass ratio of 1:15, reflux at 90 °C for 3 h, centrifuge and separate. The supernatant is refluxed with acetic acid and hydrochloric acid with a volume ratio of 9:1 at 70 °C for 2 h. The precipitate is washed with water until neutral, freeze-dried, and reacted with sodium sulfite at a mass ratio of 1:0.5 at 120 °C for 2 h to obtain loofah sponge extract; Dissolve oxidized konjac glucomannan in deionized water to obtain an oxidized konjac glucomannan solution with a mass fraction of 5%. After adding silk fibroin to the oxidized konjac glucomannan solution at a mass ratio of 1:0.3, adjust the pH to 9.0, stir at 50 °C for 1 h, then add tannic acid and stir to mix evenly. The mass ratio of oxidized konjac glucomannan to tannic acid is 1:0.1. Dropwise add 0.5 mol / L ferric chloride solution, with the molar ratio of tannic acid to ferric chloride being 3:1, and stir at room temperature for 30 min to obtain a dynamic network base liquid; Mix the dynamic network base liquid with loofah extract, homogenize at a high speed of 8000 rpm at 60 °C for 15 min. Sequentially add xanthan gum, nanocellulose, and methyl cellulose, and stir at 45 °C until there are no particles. Add glycerol, aloe vera gel, sorbitol, and rosemary extract, adjust the pH to 7.0, perform vacuum homogenization at -0.08 MPa for 30 min to remove bubbles, pass through a 200-mesh sieve, and then fill and seal to obtain an environmentally friendly glue for children's picture books based on natural plant extracts.

[0020] Example 2: An environmentally friendly glue for children's picture books based on natural plant extracts, its preparation method and application, including the following steps: Prepare the components: 10 parts by weight of loofah extract, 50 parts by weight of dynamic network base liquid, 1.5 parts by weight of xanthan gum, 2.3 parts by weight of nanocellulose, 0.6 parts by weight of methyl cellulose, 4 parts by weight of aloe vera gel, 2 parts by weight of glycerol, 4 parts by weight of sorbitol, and 0.7 parts by weight of rosemary extract; Among them, the dynamic network base liquid is obtained by mixing oxidized konjac glucomannan, silk fibroin, tannic acid, and ferric chloride; Mechanically crush dry loofah to a particle size of 0.5 mm, degrease it with 70% ethanol at 60 °C for 2 h to obtain degreased loofah. Mix the degreased loofah with 2 mol / L NaOH solution at a mass ratio of 1:15, reflux at 90 °C for 3 h, perform centrifugal separation. The supernatant is refluxed with acetic acid and hydrochloric acid with a volume ratio of 9:1 at 70 °C for 2 h. The precipitate is washed with water until neutral, freeze-dried, and reacted with sodium sulfite at a mass ratio of 1:0.5 at 120 °C for 2 h to obtain loofah extract; Dissolve oxidized konjac glucomannan in deionized water to obtain an oxidized konjac glucomannan solution with a mass fraction of 5%. After adding silk fibroin to the oxidized konjac glucomannan solution at a mass ratio of 1:0.4, adjust the pH to 9.0, stir at 50 °C for 1 h, then add tannic acid and stir to mix evenly. The mass ratio of oxidized konjac glucomannan to tannic acid is 1:0.15. Dropwise add 0.5 mol / L ferric chloride solution, with the molar ratio of tannic acid to ferric chloride being 3:1, and stir at room temperature for 30 min to obtain a dynamic network base liquid; Mix the dynamic network base liquid with loofah extract, homogenize at 8000 rpm for 15 min at 60 °C, successively add xanthan gum, nanocellulose and methylcellulose, stir at 45 °C until there are no particles, add glycerol, aloe vera gel, sorbitol and rosemary extract, adjust the pH to 7.0, homogenize under vacuum at -0.08 MPa for 30 min to remove air bubbles, sieve through a 200-mesh sieve and then fill and seal to obtain an environmentally friendly glue for children's picture books based on natural plant extracts.

[0021] Example 3: An environmentally friendly glue for children's picture books based on natural plant extracts, its preparation method and application, including the following steps: Prepare the components: 10 parts by weight of loofah extract, 55 parts by weight of dynamic network base liquid, 1.5 parts by weight of xanthan gum, 2.3 parts by weight of nanocellulose, 0.6 parts by weight of methylcellulose, 4 parts by weight of aloe vera gel, 2 parts by weight of glycerol, 4 parts by weight of sorbitol and 0.7 parts by weight of rosemary extract; Among them, the dynamic network base liquid is obtained by mixing oxidized konjac glucomannan, silk fibroin, tannic acid and ferric chloride; Mechanically crush dry loofah to a particle size of 0.5 mm, degrease it with 70% ethanol at 60 °C for 2 h to obtain defatted loofah. Mix the defatted loofah with 2 mol / L NaOH solution at a mass ratio of 1:15, reflux at 90 °C for 3 h, centrifuge and separate. The supernatant is refluxed with acetic acid and hydrochloric acid at a volume ratio of 9:1 at 70 °C for 2 h. The precipitate is washed with water until neutral, freeze-dried, and reacted with sodium sulfite at a mass ratio of 1:0.5 at 120 °C for 2 h to obtain loofah extract; Dissolve oxidized konjac glucomannan in deionized water to obtain an oxidized konjac glucomannan solution with a mass fraction of 5%. After adding silk fibroin to the oxidized konjac glucomannan solution at a mass ratio of 1:0.5, adjust the pH to 9.0, stir at 50 °C for 1 h, then add tannic acid and stir to mix evenly. The mass ratio of oxidized konjac glucomannan to tannic acid is 1:0.2. Dropwise add 0.5 mol / L ferric chloride solution. The molar ratio of tannic acid to ferric chloride is 3:1. Stir at room temperature for 30 min to obtain the dynamic network base liquid; Mix the dynamic network base liquid with loofah extract, homogenize at 8000 rpm for 15 min at 60 °C, successively add xanthan gum, nanocellulose and methylcellulose, stir at 45 °C until there are no particles, add glycerol, aloe vera gel, sorbitol and rosemary extract, adjust the pH to 7.0, homogenize under vacuum at -0.08 MPa for 30 min to remove air bubbles, sieve through a 200-mesh sieve and then fill and seal to obtain an environmentally friendly glue for children's picture books based on natural plant extracts.

[0022] Example 4: An environmentally friendly glue for children's picture books based on natural plant extracts, its preparation method and application, including the following steps: Preparation components: 13 parts by weight of loofah sponge extract, 55 parts by weight of dynamic network base liquid, 1.5 parts by weight of xanthan gum, 2.3 parts by weight of nanocellulose, 0.6 parts by weight of methylcellulose, 4 parts by weight of aloe vera gel, 2 parts by weight of glycerol, 4 parts by weight of sorbitol, and 0.7 parts by weight of rosemary extract; Among them, the dynamic network base liquid is obtained by mixing oxidized konjac glucomannan, silk fibroin, tannic acid, and ferric chloride; Mechanically crush the dried loofah sponge to a particle size of 0.5 mm, degrease it with 70% ethanol at 60 °C for 2 h to obtain defatted loofah sponge. Mix the defatted loofah sponge with 2 mol / L NaOH solution at a mass ratio of 1:15, reflux at 90 °C for 3 h, centrifuge and separate. The supernatant is refluxed with acetic acid and hydrochloric acid with a volume ratio of 9:1 at 70 °C for 2 h. The precipitate is washed with water until neutral, freeze-dried, and reacted with sodium sulfite at a mass ratio of 1:0.5 at 120 °C for 2 h to obtain loofah sponge extract; Dissolve oxidized konjac glucomannan in deionized water to obtain an oxidized konjac glucomannan solution with a mass fraction of 5%. After adding silk fibroin to the oxidized konjac glucomannan solution at a mass ratio of 1:0.5, adjust the pH to 9.0, stir at 50 °C for 1 h, then add tannic acid and stir to mix evenly. The mass ratio of oxidized konjac glucomannan to tannic acid is 1:0.2. Dropwise add 0.5 mol / L ferric chloride solution. The molar ratio of tannic acid to ferric chloride is 3:1. Stir at room temperature for 30 min to obtain the dynamic network base liquid; Mix the dynamic network base liquid with the loofah sponge extract, homogenize at 8000 rpm at 60 °C for 15 min. Sequentially add xanthan gum, nanocellulose, and methylcellulose, and stir at 45 °C until there are no particles. Add glycerol, aloe vera gel, sorbitol, and rosemary extract, adjust the pH to 7.0, homogenize under -0.08 MPa vacuum for 30 min to remove bubbles, pass through a 200-mesh sieve and then fill and seal to obtain an environmentally friendly glue for children's picture books based on natural plant extracts.

[0023] Example 5: An environmentally friendly glue for children's picture books based on natural plant extracts, its preparation method and application, including the following steps: Preparation components: 15 parts by weight of loofah sponge extract, 55 parts by weight of dynamic network base liquid, 1.5 parts by weight of xanthan gum, 2.3 parts by weight of nanocellulose, 0.6 parts by weight of methylcellulose, 4 parts by weight of aloe vera gel, 2 parts by weight of glycerol, 4 parts by weight of sorbitol, and 0.7 parts by weight of rosemary extract; Among them, the dynamic network base liquid is obtained by mixing oxidized konjac glucomannan, silk fibroin, tannic acid, and ferric chloride; Mechanically crush the dried loofah sponge to a particle size of 0.5 mm, degrease it with 70% ethanol at 60 °C for 2 h to obtain degreased loofah sponge. Mix the degreased loofah sponge with 2 mol / L NaOH solution at a mass ratio of 1:15, reflux at 90 °C for 3 h, centrifuge, reflux the supernatant with acetic acid and hydrochloric acid with a volume ratio of 9:1 at 70 °C for 2 h, wash the precipitate until neutral, freeze-dry, and react with sodium sulfite at a mass ratio of 1:0.5 at 120 °C for 2 h to obtain loofah sponge extract; Dissolve oxidized konjac glucomannan in deionized water to obtain an oxidized konjac glucomannan solution with a mass fraction of 5%. After adding silk fibroin to the oxidized konjac glucomannan solution at a mass ratio of 1:0.5, adjust the pH to 9.0, stir at 50 °C for 1 h, then add tannic acid and stir to mix evenly. The mass ratio of oxidized konjac glucomannan to tannic acid is 1:0.2. Dropwise add 0.5 mol / L ferric chloride solution, and the molar ratio of tannic acid to ferric chloride is 3:1. Stir at room temperature for 30 min to obtain a dynamic network base liquid; Mix the dynamic network base liquid with the loofah sponge extract, homogenize at high speed at 8000 rpm at 60 °C for 15 min, sequentially add xanthan gum, nanocellulose and methyl cellulose, stir at 45 °C until there are no particles, add glycerol, aloe vera gel, sorbitol and rosemary extract, adjust the pH to 7.0, homogenize under vacuum at -0.08 MPa for 30 min to defoam, pass through a 200-mesh sieve and then fill and seal to obtain an environment-friendly glue for children's picture books based on natural plant extracts.

[0024] Example 6: An environment-friendly glue for children's picture books based on natural plant extracts, its preparation method and application, including the following steps: Prepare the components: 15 parts by weight of loofah sponge extract, 55 parts by weight of dynamic network base liquid, 0.5 part by weight of xanthan gum, 1.2 parts by weight of nanocellulose, 0.3 part by weight of methyl cellulose, 2 parts by weight of aloe vera gel, 1 part by weight of glycerol, 2 parts by weight of sorbitol and 0.3 part by weight of rosemary extract; Among them, the dynamic network base liquid is obtained by mixing oxidized konjac glucomannan, silk fibroin, tannic acid and ferric chloride; Mechanically crush the dried loofah sponge to a particle size of 0.5 mm, degrease it with 70% ethanol at 60 °C for 2 h to obtain degreased loofah sponge. Mix the degreased loofah sponge with 2 mol / L NaOH solution at a mass ratio of 1:15, reflux at 90 °C for 3 h, centrifuge, reflux the supernatant with acetic acid and hydrochloric acid with a volume ratio of 9:1 at 70 °C for 2 h, wash the precipitate until neutral, freeze-dry, and react with sodium sulfite at a mass ratio of 1:0.5 at 120 °C for 2 h to obtain loofah sponge extract; Dissolve oxidized konjac glucomannan in deionized water to obtain an oxidized konjac glucomannan solution with a mass fraction of 5%. After adding silk fibroin to the oxidized konjac glucomannan solution at a mass ratio of 1:0.5, adjust the pH to 9.0, stir at 50 °C for 1 h, then add tannic acid and stir to mix evenly. The mass ratio of oxidized konjac glucomannan to tannic acid is 1:0.2. Dropwise add 0.5 mol / L ferric chloride solution, and the molar ratio of tannic acid to ferric chloride is 3:1. Stir at room temperature for 30 min to obtain a dynamic network base liquid; Mix the dynamic network base liquid with loofah extract, homogenize at 8000 rpm at 60 °C for 15 min. Sequentially add xanthan gum, nanocellulose and methyl cellulose, and stir at 45 °C until there are no particles. Add glycerol, aloe vera gel, sorbitol and rosemary extract, adjust the pH to 7.0, homogenize under vacuum at -0.08 MPa for 30 min to remove bubbles, sieve through a 200-mesh sieve and then fill and seal to obtain an environmentally friendly glue for children's picture books based on natural plant extracts.

[0025] Comparative Example 1: Adopt the method of Example 5, and replace the dynamic network base liquid with starch.

[0026] Comparative Example 2: Adopt the method of Example 5, directly use oxidized konjac glucomannan and silk fibroin, and do not modify oxidized konjac glucomannan and silk fibroin through tannic acid and ferric chloride.

[0027] The environmentally friendly glue for children's picture books based on natural plant extracts prepared by the present invention using a dynamic network base liquid, wherein the performance index test items and test standards of the glue are as follows: Cut 80 g / m² coated paper into test pieces of 25 mm × 100 mm, coat the glue (coating amount 0.2 g / cm²), the bonding area is 25 mm × 25 mm, keep the pressure at 0.5 MPa for 30 s to compact, and after curing for 24 hours, conduct 180° peeling at a speed of 100 mm / min through a universal material testing machine, record the average peeling strength (N / 25 cm), and evaluate the adhesion of the glue to the picture book paper; simulate the scenario of children repeatedly turning pages, test the anti-fatigue performance of the bonding part, prepare bonding test pieces with a bonding area of 10 mm × 50 mm, fix the test pieces on a folding tester, the bending angle is 180°, the frequency is 60 times / min, test the peeling strength after 100 open-close operations, and test the number of bending times when the glue layer cracks.

[0028] Through the above standards, test the environmentally friendly glue for children's picture books based on natural plant extracts prepared in the above Examples 1-6 and Comparative Examples 1-2, and the obtained data are shown in Table 1: Table 1 Performance data of Examples 1-6 and Comparative Examples 1-2

[0029] The above data fully demonstrate that, compared with Comparative Examples 1-2, Examples 1-6 can clearly show the effect of the dynamic network base liquid on the bonding strength and bending resistance of the children's picture book environmental protection glue based on natural plant extracts.

[0030] Since the present invention uses a dynamic network base liquid to prepare a children's picture book environmental protection glue based on natural plant extracts, the performance of the children's picture book environmental protection glue based on natural plant extracts is effectively improved by the dynamic network base liquid, as follows: It can be seen from Examples 1-3 that as the content and component ratio of the dynamic network base liquid continuously increase, the bonding strength and bending resistance of the children's picture book environmental protection glue based on natural plant extracts are significantly improved. The dynamic covalent bonds formed by the aldehyde groups of oxidized konjac glucomannan and the amino groups of silk fibroin increase with the increase of the base liquid ratio, thus forming a denser covalent crosslinking network with higher interfacial adhesion ability. The proportion of dynamic non-covalent bonds formed by tannic acid-Fe³⁺ coordination bonds synchronously increases, providing an additional energy dissipation path and enhancing the anti-shear ability. Therefore, the bending resistance is significantly improved.

[0031] It can be seen from Examples 3-5 that as the content of loofah sponge extract continuously increases, the bonding strength and bending resistance of the children's picture book environmental protection glue based on natural plant extracts continuously increase. The loofah sponge extract is rich in lignin, and its rigid aromatic ring structure can enhance the initial bonding strength of the glue layer and provide additional support for the glue. Since the phenolic hydroxyl groups and sulfonic acid groups in lignin can also form coordination bonds with Fe³⁺, the stability of the dynamic network is further enhanced. Moreover, the loofah sponge extract, as a natural filler, fills the pores in the dynamic network base liquid, reduces the internal defects of the glue layer, improves the overall mechanical properties, and delays the cracking of the glue layer. At the same time, the polar groups in the loofah sponge extract can form hydrogen bonds or van der Waals forces with the cellulose on the paper surface, enhancing the adhesion of the glue to the paper. Therefore, the loofah sponge extract optimizes the glue performance through the dual mechanisms of chemical coordination enhancement and physical toughening.

[0032] It can be seen from Examples 5 and 6 that as the content of other components continuously changes, the bonding strength and bending resistance of the children's picture book environmental protection glue based on natural plant extracts do not change significantly, indicating that small changes within a certain range of other components are not sufficient to significantly affect the bonding strength and bending resistance of the children's picture book environmental protection glue based on natural plant extracts.

[0033] According to the above test experiments, the children's picture book environmental protection glue based on natural plant extracts prepared according to Example 5 has the optimal performance, so Example 5 is taken as the optimal example; It can be seen from the comparison between Example 5 and Comparative Examples 1-2 that: In Comparative Example 1, the dynamic network base liquid is replaced with starch. The bonding strength and bending resistance of the environmentally friendly glue for children's picture books based on natural plant extracts are worse. Since the starch molecules are cross-linked by hydrogen bonds and van der Waals forces to form a rigid network, it lacks the reversibility of dynamic bonds and is prone to brittle fracture when stress is concentrated. It cannot release energy by bond reorganization when bending, and the cracks expand rapidly, resulting in debonding, making it unable to adapt to repeated stress.

[0034] Comparative Example 2 directly uses oxidized konjac glucomannan and silk fibroin, and does not modify the oxidized konjac glucomannan and silk fibroin by tannic acid and ferric chloride. The bonding strength and bending resistance of the environmentally friendly glue for children's picture books based on natural plant extracts are worse. When the dynamic network only relies on the action of dynamic covalent bonds, its cross-linking density is significantly lower, which leads to an unstable network structure. The lack of tannic acid-Fe³⁺ coordination bonds makes the network lack fast-response dynamic bonds, which leads to poor bonding strength and bending resistance.

[0035] In summary, through the dynamic network base liquid and loofah extract, in the dynamic network base liquid, the aldehyde group of oxidized konjac glucomannan forms a reversible covalent bond with the amino group of silk protein, giving the glue self-healing ability. At the same time, the ortho-phenolic hydroxyl group of tannic acid coordinates with Fe³⁺ in ferric chloride to form a stable three-dimensional network, which significantly enhances the cohesion and fatigue resistance of the glue layer. The loofah extract is rich in lignin, and its phenolic hydroxyl group further coordinates with Fe³⁺, which strengthens the stability of the dynamic network and reinforces the glue layer through a rigid structure to improve the initial bonding strength. The synergistic effect of the two enables the glue to disperse stress through bond reorganization during repeated bending and maintain high peel strength.

[0036] 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 by the above embodiments, and the above embodiments and descriptions are only preferred examples of the present invention, and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. Environmentally friendly glue for children's picture books based on natural plant extracts, characterized in that: The invention comprises the following components: 10-15 parts by weight of loofah extract, 45-55 parts by weight of dynamic network base liquid, 0.5-1.5 parts by weight of xanthan gum, 1.2-2.3 parts by weight of nanocellulose, 0.3-0.6 parts by weight of methylcellulose, 2-4 parts by weight of aloe vera gel, 1-2 parts by weight of glycerol, 2-4 parts by weight of sorbitol and 0.3-0.7 parts by weight of rosemary extract; The dynamic network base liquid is obtained by mixing oxidized konjac glucomannan, silk fibroin, tannic acid and ferric chloride.

2. The environmentally friendly glue for children's picture books based on natural plant extracts according to claim 1, characterized in that: The specific preparation steps of the loofah extract are: The dried loofah was mechanically crushed to a particle size of 0.5-1 mm, and defatted with 70-75% ethanol at 60-65°C for 2-3 h to obtain defatted loofah. The defatted loofah was mixed with 2-3 mol / L NaOH solution at a mass ratio of 1:13-15, refluxed at 85-90°C for 3-4 h, and centrifuged. The supernatant was refluxed with acetic acid and hydrochloric acid at a volume ratio of 9:1 at 70-75°C for 2-3 h. The precipitate was washed with water until neutral, freeze-dried, and reacted with sodium sulfite at 120-125°C for 2-3 h to obtain the loofah extract.

3. The environmentally friendly glue for children's picture books based on natural plant extracts according to claim 2, characterized in that: The mass ratio of the precipitate to sodium sulfite is 1:0.3-0.

5.

4. The environmentally friendly glue for children's picture books based on natural plant extracts according to claim 1, characterized in that: The preparation method of the dynamic network base liquid is as follows: The oxidized konjac glucomannan is dissolved in deionized water to obtain an oxidized konjac glucomannan solution. After adding silk fibroin to the oxidized konjac glucomannan solution, the pH is adjusted to 8.5-9.0, stirred at 40-50° C. for 1-2 hours, and then tannic acid is added and stirred to mix evenly. A 0.5-1 mol / L ferric chloride solution is added dropwise, and stirred at room temperature for 20-30 minutes to obtain a dynamic network base liquid.

5. The environmentally friendly glue for children's picture books based on natural plant extracts according to claim 4, characterized in that: The mass fraction of the oxidized konjac glucomannan solution is 5-8%.

6. The environmentally friendly glue for children's picture books based on natural plant extracts according to claim 4, characterized in that: The mass ratio of the oxidized konjac glucomannan to the silk fibroin is 1:0.3-0.

5.

7. The environmentally friendly glue for children's picture books based on natural plant extracts according to claim 4, characterized in that: The mass ratio of the oxidized konjac glucomannan to tannic acid is 1:0.1-0.

2.

8. The environmentally friendly glue for children's picture books based on natural plant extracts according to claim 4, characterized in that: The molar ratio of the tannic acid to the ferric chloride is 2-4:

1.

9. A method for preparing environmentally friendly glue for children's picture books based on natural plant extracts, which is used to prepare the environmentally friendly glue for children's picture books based on natural plant extracts as claimed in any one of claims 1 to 8, characterized in that: The steps include: The dynamic network base liquid is mixed with the loofah extract, and the mixture is homogenized at 8000-9000 rpm for 15-20 min at 60° C., xanthan gum, nanocellulose and methylcellulose are added in sequence, and stirred at 40-45° C. until there are no particles, glycerin, aloe vera gel, sorbitol and rosemary extract are added, the pH is adjusted to 6.5-7.5, and the mixture is homogenized in a vacuum at -0.08 MPa for 25-30 min for degassing. The mixture is sieved through a 200-mesh sieve and then filled and sealed to obtain an environmentally friendly glue for children's picture books based on natural plant extracts.

10. Application of environmentally friendly glue for children's picture books based on natural plant extracts, comprising environmentally friendly glue for children's picture books based on natural plant extracts prepared by the method for preparing environmentally friendly glue for children's picture books based on natural plant extracts as claimed in claim 9, characterized in that: The environmentally friendly glue for children's picture books based on natural plant extracts is used for bonding picture books to paper materials.

Images