Coated fabric with the wetting effect of rice paper

Abstract

The present invention provides a coated fabric with the effect of wetting rice paper, which includes a polyester plain weave fabric base layer, an esterification layer, and a scrape-coated slurry layer. The esterification layer is tightly bonded to the upper surface of the polyester plain weave fabric base layer and the gaps between the polyester warp and weft threads, and the scrape-coated slurry layer is integrally formed with the esterification layer. The main components of the scrape-coated slurry layer are oxidized starch and carboxylated nanocellulose, and the content of hydroxyl functional groups in the oxidized starch in the scrape-coated slurry layer is greater than the content of carboxyl functional groups in the carboxylated nanocellulose. The esterification layer is formed by an esterification reaction between the surplus hydroxyl functional groups of the oxidized starch and citric acid impregnated on the surface of the polyester plain weave fabric base layer. In the present invention, citric acid is used as a mediator to react with the surplus hydroxyl groups in the scrape-coated slurry to form an esterification layer, thereby making the bonding force between the scrape-coated slurry and the polyester plain weave fabric base layer better; and the anhydrous form of citric acid can also absorb water to obtain a hydrate, thereby making the wetting effect of the coated fabric better.

Description

Technical Field

[0001] The present invention relates to the technical field of canvas, and particularly to a coated fabric with the wetting effect of rice paper. Background Art

[0002] Using canvas for painting is usually only used in the field of Western oil painting. Chinese ink painting generally can only choose rice paper for painting. However, the traditional production process of rice paper has high requirements for the process environment, climate, temperature, and the skills of operators, resulting in the difficulty of continuous production of rice paper. Moreover, the market price of high-quality rice paper is relatively high, and the purchase and use costs for ordinary painters are also high.

[0003] The applicant has previously applied for multiple patents for canvases with the effect of rice paper. For example, a kind of rice paper-like coating material, rice paper-like paper, preparation method and its application disclosed in Patent Publication No. CN117738024A, a preparation method of an imitation rice paper bleeding hand-painted canvas disclosed in Patent Application Publication No. CN115341381A, and an ink-absorbing and quick-drying canvas disclosed in Patent Publication No. CN103741481B. However, the domestic research and development of this technology is limited, and there are still some problems. For example, a method of combining fillers (such as cellulose fibers, nano calcium carbonate, etc.) and sizing agents (such as starch, modified starch, etc.) is used to scrape and coat on the surface of fabrics. However, when combined with chemical fiber materials such as polyester as the base material, there is still room for improvement in the bonding force between the sizing agent and polyester. Summary of the Invention

[0004] The technical problem to be solved by the embodiments of the present invention is to provide a coated fabric with the wetting effect of rice paper, and solve the problem of weak bonding force between the coated fabric with the wetting effect of rice paper made of polyester plain weave fabric as the base material and the slurry.

[0005] To solve the above technical problem, the present invention provides a coated fabric with the wetting effect of rice paper, which includes a polyester plain weave fabric base layer, an esterification layer, and a scrape-coated slurry layer. The esterification layer is tightly combined on the upper surface of the polyester plain weave fabric base layer and in the gaps between the polyester warp and weft threads. The scrape-coated slurry layer is integrally formed with the esterification layer. The main components of the scrape-coated slurry layer are oxidized starch and carboxylated nanocellulose, and the oxidized starch and carboxylated nanocellulose are formulated in a weight ratio of (3 - 20):1. Moreover, the content of hydroxyl functional groups in the oxidized starch in the scrape-coated slurry layer is greater than the content of carboxyl functional groups in the carboxylated nanocellulose. The esterification layer is formed by an esterification reaction between the surplus hydroxyl functional groups of the oxidized starch and citric acid impregnated on the surface of the polyester plain weave fabric base layer.

[0006] The thickness of the polyester plain weave fabric base layer is 0.3 - 0.6 mm; the average thickness of the scrape-coated slurry layer is between 0.1 - 0.2 mm; the thickness of the esterification layer on the upper surface of the polyester plain weave fabric base layer is between 0.02 - 0.05 mm, and the depth of the esterification layer sinking into the gaps between the polyester warp and weft threads is between 0.2 - 0.4 mm; among them, the formation of the esterification layer is to first dip the polyester plain weave fabric base layer in a citric acid solution, and then use wind force to make the slurry coated on the polyester plain weave fabric base layer penetrate into the gaps between the warp and weft threads of the polyester plain weave fabric base layer, and heat to cause an esterification reaction between the oxidized starch and citric acid in the slurry.

[0007] The citric acid is obtained by immersing the polyester plain weave fabric base layer in a citric acid solution before scraping the slurry, or by spraying it onto the upper surface of the polyester plain weave fabric base layer. The citric acid content in the citric acid solution is 3 - 5 wt%.

[0008] Before scraping the slurry, hot air also needs to be blown onto the lower surface of the polyester plain weave fabric base layer to evaporate the water in the citric acid solution and retain the citric acid on the upper surface of the polyester plain weave fabric base layer and in the gaps between the polyester warp and weft threads.

[0009] The temperature of the hot air is between 60 - 75 °C to avoid decomposing the citric acid hydrate.

[0010] In the scrape-coated slurry, the weight of the oxidized starch and carboxylated nanocellulose does not exceed 10% of the total weight.

[0011] The scrape-coated slurry also contains 0.5 wt% of a waterborne polyurethane thickener, 0.02 wt% of an isothiazolinone preservative, 0.2 wt% of a leveling agent, 0.15 wt% of a dispersant, and 0.15 wt% of an antifoaming agent.

[0012] The pulping process of the scrape-coated slurry includes:

[0013] Preparing an oxidized starch solution and gelatinizing the oxidized starch solution;

[0014] Preparing a carboxylated nanocellulose dispersion;

[0015] Mix the gelatinized oxidized starch solution and the carboxylated nanocellulose dispersion in a mass ratio of 2:8, and then mix them evenly by magnetic stirring.

[0016] The carboxylated nanocellulose is prepared by Acetobacter xylinum and then subjected to a carboxylation reaction.

[0017] The preparation process of the carboxylated nanocellulose includes:

[0018] (1) Acetobacter xylinum biosynthesizes nanocellulose;

[0019] 1. Culture Conditions

[0020] Culture medium: Commonly used HS medium (containing glucose, yeast extract, peptone, phosphate, etc.), providing carbon source and nitrogen source.

[0021] Culture method:

[0022] Promote bacterial dispersion through stirring or airlift reactor to generate granular cellulose.

[0023] Culture period: Usually 5 - 7 days, temperature 28 - 30 °C, pH 4.5 - 6.0.

[0024] 2. Synthesis mechanism of nanocellulose

[0025] Acetobacter xylinum polymerizes glucose into β-1,4-glucan chains through the cellulose synthase complex on the cell membrane.

[0026] Multiple glucan chains self-assemble into nanofibers (diameter 3 - 50 nm) through hydrogen bonds to form a three-dimensional network structure.

[0027] 3. Post-treatment

[0028] Purification: Remove cell residues and medium residues, common steps:

[0029] Alkali treatment (0.1 - 1 M NaOH, 80 °C, 1 - 2 hours) to dissolve bacterial proteins.

[0030] Wash repeatedly with water until neutral.

[0031] Mechanical homogenization or ultrasonic treatment to disperse nanofibers.

[0032] (II) Carboxylation reaction of nanocellulose: Chemical grafting;

[0033] The chemical grafting includes: introducing carboxylic acid groups through esterification or etherification reactions (such as reacting with maleic anhydride).

[0034] The aspect ratio of the carboxylated nanocellulose is between 25 - 100, where the diameter is 10 - 20 nm and the length is 0.5 - 1 μm.

[0035] After the scraping slurry is scraped on the upper surface of the polyester plain fabric substrate, hot air at a temperature of 60 - 75 °C is blown vertically onto the slurry on the polyester plain fabric substrate. After the slurry is subjected to the pressure of the hot air, a part of the slurry enters the gaps between the warp and weft threads of the polyester plain fabric substrate;

[0036] After the slurry is dried and the esterification reaction between the surplus hydroxyl groups in the slurry and the carboxyl groups of citric acid is sufficient to form an esterification layer, hot air at a temperature of 78-90°C is blown upward from the lower surface of the polyester plain fabric base layer to decompose the remaining citric acid hydrate to obtain anhydrate.

[0037] The coated cloth with rice paper wetting effect provided by the present invention uses citric acid as a medium to react with surplus hydroxyl groups in the scraping slurry to form an esterification layer, thereby improving the bonding strength between the scraping slurry and the polyester plain weave fabric base layer; and the anhydrate of citric acid can also absorb water to obtain a hydrate, thereby improving the wetting effect of the coated cloth. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the planar structure of the polyester plain weave fabric base layer (the size ratio of the gap and the warp and weft lines shown in the figure is not the real ratio, the actual gap is very small, and the gap is enlarged for explanation).

[0039] Figure 2 Schematic diagram of the cross-sectional structure of the polyester plain weave fabric base layer.

[0040] Figure 3 Schematic diagram of the layered structure of the coated cloth with rice paper wetting effect.

[0041] Figure 4 Schematic diagram of the layered structure of the coated cloth with rice paper wetting effect (with Figure 3 The cutting position is different).

[0042] Figure 5 This is an electron microscope photo of the coated cloth with the wetting effect of rice paper (the picture shows the random distribution of linear carboxylated nanocellulose).

[0043] Figure 6 This is an electron microscope photo of the green pigment soaked in the coated cloth with the wetting effect of rice paper.

[0044] Figure 7 This is an electron microscope photograph of the red pigment soaked in the coated cloth with the wetting effect of rice paper.

[0045] Figure 8 This is an electron microscope photograph of the coated cloth with the wetting effect of rice paper and the infiltrated black pigment.

[0046] Figure 9 This is an electron microscope photo of the red stripe wetting effect of the coated cloth with the wetting effect of rice paper.

[0047] In the figure: 1- polyester plain weave fabric base layer, 2- esterification layer, 3- scraping slurry layer; 11- warp, 12- weft, 13- gap. DETAILED DESCRIPTION

[0048] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the following describes in detail the specific embodiments of the present invention with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0049] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can also be a central element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0051] Combined with Figures 1-9As shown in the figure, the present invention provides a coated fabric with the effect of wetting rice paper, which includes a polyester plain weave fabric base layer 1, an esterification layer 2, and a scrape-coated slurry layer 3. The esterification layer 2 is tightly bonded to the upper surface of the polyester plain weave fabric base layer 1 and the gaps 13 between the polyester warp and weft threads. The scrape-coated slurry layer 3 is integrally formed with the esterification layer 2. The main components of the scrape-coated slurry layer 3 are oxidized starch and carboxylated nanocellulose, and the oxidized starch and carboxylated nanocellulose are formulated in a weight ratio of (3-20):1. Moreover, the content of hydroxyl functional groups in the oxidized starch in the scrape-coated slurry layer is greater than the content of carboxyl functional groups in the carboxylated nanocellulose. The esterification layer 2 is formed by an esterification reaction between the surplus hydroxyl functional groups of the oxidized starch and the citric acid impregnated on the surface of the polyester plain weave fabric base layer 1. That is to say, after the scrape-coated slurry layer 3 is scrape-coated on the polyester plain weave fabric base layer, the oxidized starch in the scrape-coated slurry contacts the polyester plain weave fabric base layer 1, and then an esterification reaction occurs with the citric acid attached to the polyester plain weave fabric base layer at an appropriate temperature (such as about 60°C). The citric acid is obtained by immersing the polyester plain weave fabric base layer 1 in a citric acid solution, so that the citric acid solution adheres to the polyester plain weave fabric base layer. Then, the citric acid solution on the polyester plain weave fabric base layer can be dried by a certain temperature, such as hot air below 60°C, to ensure that the citric acid does not undergo a decomposition reaction, thereby increasing the concentration of the remaining citric acid solution for easy contact and reaction with the scrape-coated slurry.

[0052] The thickness of the polyester plain weave fabric base layer is 0.3-0.6 mm; the average thickness of the scrape-coated slurry layer is between 0.1-0.2 mm, and the maximum thickness of the scrape-coated slurry layer can reach 0.3 mm; the thickness of the esterification layer on the upper surface of the polyester plain weave fabric base layer is between 0.02-0.05 mm, and the depth of the esterification layer sinking into the gaps between the polyester warp and weft threads is between 0.2-0.4 mm. This sinking depth is very important as it can greatly increase the bonding force between the polyester plain weave fabric base layer 1 and the slurry thereon. Among them, the formation of the esterification layer is that the polyester plain weave fabric base layer is first impregnated with a citric acid solution, and then the slurry coated on the polyester plain weave fabric base layer is infiltrated into the gaps between the warp and weft threads of the polyester plain weave fabric base layer by wind force, and heating causes an esterification reaction between the oxidized starch and citric acid in the slurry.

[0053] The citric acid is obtained by immersing the polyester plain weave fabric base layer in a citric acid solution before scrape-coating the slurry, or by spraying it onto the upper surface of the polyester plain weave fabric base layer. The content of citric acid in the citric acid solution is 3-5 wt%.

[0054] Before scraping the slurry, it is also necessary to blow hot air onto the lower surface of the polyester plain weave fabric base layer 1 to evaporate the moisture in the citric acid solution and retain the citric acid on the upper surface of the polyester plain weave fabric base layer and in the gaps between the polyester warp and weft threads. The function of blowing hot air onto the lower surface of the polyester plain weave fabric base layer 1 is also to blow the citric acid solution from bottom to top, so that more of the citric acid solution moves towards the upper surface of the polyester plain weave fabric base layer 1. The upper surface of the polyester plain weave fabric base layer serves as the sizing surface and comes into contact with the slurry, so that the citric acid can come into more sufficient contact with the slurry and react fully to obtain a better bonding force with the slurry.

[0055] The temperature of the hot air is between 60 - 75 °C to avoid decomposing the citric acid hydrate; since the hydrate in the citric acid solution will start to decompose when the temperature exceeds 78 °C, it is necessary to avoid the decomposition of the citric acid hydrate into the anhydrous form when heating and evaporating the citric acid.

[0056] In the scraped slurry, the weight of oxidized starch and carboxylated nanocellulose does not exceed 10% of the total weight, and is preferably 1% - 1.5%.

[0057] The scraped slurry also contains 0.5 wt% of an aqueous polyurethane thickener, 0.02 wt% of an isothiazolinone preservative, 0.2 wt% of a leveling agent, 0.15 wt% of a dispersant, and 0.15 wt% of an antifoaming agent. These additives can be added during the mixing process of the oxidized starch paste and the carboxylated nanocellulose dispersion, and stirred thoroughly.

[0058] The pulping process of the scraped slurry includes:

[0059] Prepare an oxidized starch solution and gelatinize the oxidized starch solution; specifically, modify the nano-starch to obtain oxidized starch, then mix the oxidized starch and pure water and stir evenly, and then heat to 62 - 68 °C to gelatinize the oxidized starch;

[0060] Prepare a carboxylated nanocellulose dispersion; specifically, mix carboxylated nanocellulose with pure water, and then stir evenly to form a dispersion;

[0061] Mix the gelatinized oxidized starch solution and the carboxylated nanocellulose dispersion in a mass ratio of 2:8, then add additives such as thickener, preservative, leveling agent, dispersant, and antifoaming agent, and then mix evenly by magnetic stirring.

[0062] The carboxylated nanocellulose is prepared by Acetobacter xylinum and then undergoes a carboxylation reaction, and the carboxyl content on its surface is 1.5 - 2.5 mmol / g.

[0063] The preparation process of the carboxylated nanocellulose includes:

[0064] (1) Gluconacetobacter xylinus produces nanocellulose through biosynthesis;

[0065] 1. Culture conditions

[0066] Culture medium: Commonly used HS medium (containing glucose, yeast extract, peptone, phosphate, etc.), which provides carbon source and nitrogen source.

[0067] Culture method:

[0068] Stirring or air-lift reactor is used to promote bacterial dispersion to produce granular cellulose.

[0069] Culture period: Usually 5 - 7 days, temperature 28 - 30 °C, pH 4.5 - 6.0.

[0070] 2. Synthesis mechanism of nanocellulose

[0071] Gluconacetobacter xylinus polymerizes glucose into β-1,4-glucan chains through the cellulose synthase complex on the cell membrane.

[0072] Multiple glucan chains self-assemble into nanofibers (diameter 3 - 50 nm) through hydrogen bonds to form a three-dimensional network structure.

[0073] 3. Post-treatment

[0074] Purification: Remove the residues of bacteria and culture medium. Common steps:

[0075] Alkali treatment (0.1 - 1 M NaOH, 80 °C, 1 - 2 hours) to dissolve bacterial proteins.

[0076] Wash repeatedly with water until neutral.

[0077] Mechanical homogenization or ultrasonic treatment to disperse nanofibers.

[0078] (2) Carboxylation reaction of nanocellulose: Chemical grafting;

[0079] The chemical grafting includes: introducing carboxylic acid groups through esterification or etherification reactions (such as reacting with maleic anhydride).

[0080] The aspect ratio of the carboxylated nanocellulose is between 25 - 100, where the diameter is 10 - 20 nm and the length is 0.5 - 1 μm.

[0081] After the scraping slurry is scraped on the upper surface of the polyester plain weave fabric substrate, hot air at 60 - 75 °C is blown vertically onto the slurry on the polyester plain weave fabric substrate. After the slurry is subjected to the pressure of the hot air, a part of the slurry enters the gaps between the warp and weft threads of the polyester plain weave fabric substrate;

[0082] After the slurry is dried and the esterification reaction between the surplus hydroxyl groups in the slurry and the carboxyl groups of citric acid is sufficient to form an esterification layer, hot air at a temperature of 78 - 90 °C is blown upward from the lower surface of the polyester plain fabric base layer to decompose the hydrate of the remaining citric acid to obtain the anhydrate. Because citric acid will decompose into water vapor and carbon dioxide when the temperature exceeds 90 °C. Citric acid has slight deliquescence in humid air and can exist in the form of anhydrate or monohydrate. When heated to 78 °C, it will decompose to obtain the anhydrate. Therefore, the temperature of the hot air is controlled to exceed 78 °C but not exceed 90 °C. The effect is to promote the decomposition of citric acid into anhydrate, but avoid further decomposition into water vapor and carbon dioxide due to too high temperature. By retaining the effective components of citric acid and making it exist in the form of anhydrate, it can play a moisture absorption role after the coated fabric is formed, making the wetting effect of the coated fabric better.

[0083] The coated fabric with the wetting effect of rice paper provided by the present invention uses citric acid as a mediator to react with the surplus hydroxyl groups in the scrape-coated slurry to form an esterification layer, so that the binding force between the scrape-coated slurry and the polyester plain fabric base layer is better; and the anhydrate of citric acid can also absorb water to obtain the hydrate, so that the wetting effect of the coated fabric is better.

[0084] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0085] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A coated cloth having a rice paper wetting effect, characterized in that: The invention comprises a polyester plain weave fabric base, an esterification layer and a scraping slurry layer, wherein the esterification layer is tightly combined with the upper surface of the polyester plain weave fabric base and the gaps between the polyester warp and weft lines, and the scraping slurry layer and the esterification layer are integrally formed; wherein the scraping slurry layer comprises oxidized starch and carboxylated nanocellulose, wherein the oxidized starch and the carboxylated nanocellulose are prepared in a weight ratio of (3-20):1, and the hydroxyl functional group content of the oxidized starch in the scraping slurry layer is greater than the carboxyl functional group content of the carboxylated nanocellulose, and the esterification layer is formed by an esterification reaction between the surplus hydroxyl functional groups of the oxidized starch and citric acid dipped or sprayed on the surface of the polyester plain weave fabric base; wherein the esterification layer is formed by firstly dipping or spraying the polyester plain weave fabric base with a citric acid solution, and then using wind to make the slurry coated on the polyester plain weave fabric base penetrate into the gaps between the warp and weft lines of the polyester plain weave fabric base, and heating to cause an esterification reaction between the oxidized starch in the slurry and the citric acid; Before applying the slurry, hot air needs to be blown to the lower surface of the polyester plain fabric base layer to evaporate the water in the citric acid solution and keep the citric acid on the upper surface of the polyester plain fabric base layer and the gaps between the polyester warp and weft lines; After the slurry is scraped onto the upper surface of the polyester plain fabric base, hot air at a temperature of 60-75°C is blown vertically onto the slurry on the polyester plain fabric base, so that the slurry is subjected to the pressure of the hot air, and a part of the slurry enters the gaps between the warp and weft lines of the polyester plain fabric base; After the slurry is dried and the esterification reaction between the surplus hydroxyl groups in the slurry and the carboxyl groups of citric acid is sufficient to form an esterification layer, hot air at a temperature of 78-90°C is blown upward from the lower surface of the polyester plain fabric base layer to decompose the remaining citric acid hydrate to obtain anhydrate.

2. The coated cloth according to claim 1, characterized in that: The thickness of the polyester plain weave fabric base layer is 0.3-0.6mm; the average thickness of the scraped slurry layer is between 0.1-0.2mm; the thickness of the esterification layer on the upper surface of the polyester plain weave fabric base layer is between 0.02-0.05mm, and the depth of the esterification layer sinking into the gap between the polyester warp and weft lines is between 0.2-0.4mm.

3. The coated cloth according to claim 1, characterized in that: The citric acid is obtained by immersing the polyester plain weave fabric base layer in a citric acid solution before applying the slurry, or by spraying the citric acid solution onto the upper surface of the polyester plain weave fabric base layer; the citric acid content in the citric acid solution is 3-5wt%.

4. The coated cloth according to claim 1, characterized in that: In the doctor blade coating slurry, the weight of the oxidized starch and the carboxylated nanocellulose does not exceed 10% of the total weight.

5. The coated cloth according to claim 4, characterized in that: The scraping slurry also includes 0.5wt% of a water-based polyurethane thickener, 0.02wt% of an isothiazolinone preservative, 0.2wt% of a leveling agent, 0.15wt% of a dispersant and 0.15wt% of a defoaming agent.

6. The coated cloth according to claim 1, characterized in that: The slurry preparation process of scraper coating includes: preparing an oxidized starch solution and gelatinizing the oxidized starch solution; preparing a carboxylated nanocellulose dispersion; The gelatinized oxidized starch solution and the carboxylated nanocellulose dispersion were mixed in a mass ratio of 2:8, and then mixed evenly by magnetic stirring.

7. The coated cloth according to claim 6, characterized in that: The carboxylated nanocellulose is prepared by Acetobacter xylinum and then subjected to a carboxylation reaction.

8. The coated cloth according to claim 6, characterized in that: The aspect ratio of the carboxylated nanocellulose is between 25 and 100, wherein the diameter is 10 to 20 nm and the length is 0.5 to 1 μm.

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