Antibacterial cultural paper, surface sizing agent, preparation method of surface sizing agent and antibacterial agent solution

Abstract

The invention provides antibacterial cultural paper, a surface sizing agent, a preparation method of the surface sizing agent and an antibacterial agent solution. The antibacterial agent solution comprises single-chain quaternary ammonium salt, double-chain quaternary ammonium salt and water. The antibacterial agent solution provided by the embodiment of the invention can be used in a surface sizing agent of cultural paper, and has the advantages of broad-spectrum bactericidal performance, low possibility of generating drug resistance to bacteria, stable alkaline environment, no heavy metal addition and the like, and positive charges of the antibacterial agent solution can neutralize negative charges of enzyme-digested starch, so that the antibacterial agent solution has a good antibacterial effect. The polar groups can form hydrogen bonds with hydroxyl groups of the enzyme-digested starch, the compatibility and dispersion stability of a composite system are enhanced, the antibacterial agent solution can endow the enzyme-digested starch with antibacterial performance, cell structures are destroyed through multiple targets, the antibacterial effect is remarkably improved, generation of bacteria is efficiently inhibited, the viscosity of the enzyme-digested starch is further reduced, and the antibacterial performance of the enzyme-digested starch is improved. The drying speed of paper is increased, the energy consumption is reduced, the sizing uniformity is improved, and the modified enzyme-digested starch is suitable for high-speed production of modern paper machines for cultural paper.

Description

Technical Field

[0001] The present application relates to the technical field of papermaking, and in particular to an antibacterial cultural paper, a surface sizing agent and a preparation method thereof, and an antibacterial agent solution. Background Art

[0002] Compared with other modified starches, enzyme-cut starch has become the mainstream choice for surface sizing of cultural paper due to its low viscosity, environmental friendliness and economy. It has the advantages of good sizing uniformity, strong permeability, and enhanced bonding between fibers. It can improve the density of the paper surface, reduce the roughness of the paper surface, reduce the phenomenon of hair loss and powder loss, and improve printing clarity. Enzyme-cut starch is a low-viscosity starch glue obtained by hydrolyzing and modifying natural starch (such as corn and cassava starch) with α-amylase or β-amylase, decomposing long-chain starch into short-chain dextrins. However, its short-chain dextrins and reducing sugars also provide a carbon source for microorganisms, making it more prone to corruption and deterioration than natural starch. As a result, paper produced by industrial surface sizing using it is more prone to the production of bacteria and mold during use, becoming a carrier of cross-transmission of bacteria.

[0003] Starch molecular chains are rich in active functional groups such as hydroxyl, carboxyl, and amino groups. Currently, research on the antimicrobial properties of starch primarily focuses on developing antimicrobial starch food packaging films. Improving starch antimicrobial properties is achieved by adding synthetic and natural antimicrobial agents. Synthetic antimicrobial agents include polyhexamethyleneguanidine hydrochloride, isothiazolinones, metal nanoparticles, and chlorine dioxide. Most organic antimicrobial agents decompose in the presence of strong acids, making them unsuitable for the alkaline environment of industrial papermaking. Metal nanoparticles are expensive and have a large surface area, making them prone to agglomeration under alkaline conditions. Furthermore, they are easily oxidized in humid environments, losing their antimicrobial activity. They are also difficult to degrade in the environment, and long-term accumulation can contaminate soil and water bodies. In industrial production, they are prone to environmental impact.

[0004] There are also many studies on the papermaking process of antibacterial paper. Preparation methods include pulp addition method, paper surface treatment method, fiber modification method, post-processing spray method, etc. Some studies have achieved antibacterial paper by adding nanosilver and chitosan to the pulp. Some studies have prepared composite coatings by nano-titanium dioxide / carboxymethyl chitosan and applied them on the surface of paper to prepare antibacterial paper. Some studies have dissolved cellulose in a sodium hydroxide / urea / zinc oxide system solvent and prepared oil-resistant antibacterial paper by casting. Some studies have modified dialdehyde cellulose with cinnamic acid to prepare modified cellulose-based non-overflow antibacterial paper. At present, antibacterial paper products are mainly concentrated in the application of food packaging paper and toilet paper, and there are no similar studies in the high-speed industrial production of modern cultural paper machines. Summary of the Invention

[0005] In a first aspect, an embodiment of the present application provides an antibacterial solution, which includes a single-chain quaternary ammonium salt, a double-chain quaternary ammonium salt, and water.

[0006] In some optional embodiments, the mass ratio of the single-chain quaternary ammonium salt to the double-chain quaternary ammonium salt is between 3:4 and 4:3.

[0007] In some optional embodiments, the mass ratio of the single-chain quaternary ammonium salt to the double-chain quaternary ammonium salt is 1:1.

[0008] In some optional embodiments, the single-chain quaternary ammonium salt is selected from any one or more of benzalkonium chloride, cetyltrimethylammonium chloride, and cetylpyridinium chloride.

[0009] In some optional embodiments, the double-chain quaternary ammonium salt is selected from any one or more of bis-octyldimethylammonium chloride, bis-decyldimethylammonium chloride, didodecyldimethylammonium chloride, cetylpyridinium chloride, dequalinium chloride, and benzethonium chloride.

[0010] In a second aspect, an embodiment of the present application provides a method for preparing a surface sizing agent for papermaking, the preparation method comprising:

[0011] placing a single-chain quaternary ammonium salt and a double-chain quaternary ammonium salt in water according to predetermined components and stirring to prepare an antibacterial solution;

[0012] preparing enzyme-cut starch glue solution;

[0013] The antibacterial agent solution is added to the enzyme-cut starch glue to obtain a surface sizing agent.

[0014] In some optional embodiments, the step of preparing enzyme-cut starch glue comprises:

[0015] placing starch in water to obtain a starch solution; wherein the starch comprises any one of corn starch and tapioca starch or a mixture of the two;

[0016] The starch solution is hydrolyzed and modified by using amylase to obtain starch glue; wherein the amylase includes any one of α-amylase and β-amylase or a mixture of the two.

[0017] In some optional embodiments, in the step of adding the antibacterial agent solution to the enzyme-cut starch glue to obtain a surface sizing agent, the absolute dry amount of the antibacterial agent solution added is 2-6% of the absolute dry amount of the enzyme-cut starch glue.

[0018] In a third aspect, an embodiment of the present application provides a surface sizing agent for papermaking, and the surface sizing agent is prepared using the preparation method described in the above embodiment.

[0019] In a fourth aspect, an embodiment of the present application provides an antibacterial cultural paper, the surface of which is provided with the surface sizing agent described in the above embodiment.

[0020] The antibacterial solution provided in the embodiments of the present application can be used in the surface sizing agent of cultural paper. The antibacterial solution has the advantages of broad-spectrum bactericidal properties, is not easy to cause bacterial resistance, has a stable alkaline environment, and does not contain heavy metals. Its positive charge can neutralize the negative charge of enzyme-cut starch, and the polar group can form hydrogen bonds with the hydroxyl groups of enzyme-cut starch, thereby enhancing the compatibility and dispersion stability of the composite system. The antibacterial solution can impart antibacterial properties to the enzyme-cut starch, and through multi-target destruction of the cell structure, achieve a significant improvement in the antibacterial effect, and effectively inhibit the production of bacteria and molds. The antibacterial solution is a low-volatile compound suitable for a long-term and stable antibacterial environment. It will not undergo significant thermal decomposition under the high-temperature environment of the paper machine. In addition, it also reduces the viscosity of the enzyme-cut starch, increases the drying rate of the paper, reduces energy consumption, and improves the uniformity of sizing. The modified enzyme-cut starch is suitable for high-speed production of cultural paper on modern paper machines. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0022] Figure 1 This is a flow chart of an embodiment of a method for preparing a surface sizing agent for papermaking according to the present application;

[0023] Figure 2 This is a schematic diagram of a process for preparing an enzymatic starch glue solution according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the stacked structure of an embodiment of the antibacterial cultural paper of the present application. DETAILED DESCRIPTION

[0025] The present application will be further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only intended to illustrate the present application and are not intended to limit the scope of the present application. Similarly, the following examples are only some examples of the present application and not all examples. All other examples obtained by those of ordinary skill in the art without creative work are intended to fall within the scope of protection of this application.

[0026] The terms "first", "second" and "third" in the embodiments of the present application are used only for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second" and "third" may explicitly or implicitly include at least one of such features. In the description of the present application, "multiple" means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined. All directional indications in the embodiments of the present application (such as up, down, left, right, front, back...) are only used to explain the relative positional relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly. The terms "including" and "having" in the embodiments of the present application and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or components inherent to these processes, methods, products or devices.

[0027] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0028] The embodiment of the present application first provides an antibacterial solution, which includes a single-chain quaternary ammonium salt, a double-chain quaternary ammonium salt and water.

[0029] Optionally, in the antibacterial solution of this embodiment, the mass ratio of the single-chain quaternary ammonium salt to the double-chain quaternary ammonium salt is between 3:4 and 4:3, specifically, it can be 3:4, 1:1, 4:3, etc. The single-chain quaternary ammonium salt is selected from any one or more of benzalkonium chloride, hexadecyltrimethylammonium chloride, and hexadecylpyridinium chloride. The double-chain quaternary ammonium salt is selected from any one or more of dioctyldimethylammonium chloride, bisdecyldimethylammonium chloride, didodecyldimethylammonium chloride, hexadecylpyridinium chloride, dequalinium chloride, and benzethonium chloride.

[0030] The high-efficiency antibacterial performance of the antibacterial agent is achieved by compounding the two (single-chain quaternary ammonium salt and double-chain quaternary ammonium salt). The two complexes have good compatibility and synergistic antibacterial properties. The single-chain structure is easier to adsorb on the surface of microorganisms, neutralizes the negative charge of the cell membrane through the positive charge, and interferes with enzyme activity or nucleic acid function. The double-chain quaternary ammonium salt (two long carbon chains C10) can effectively penetrate the double-layer lipid structure of the microbial cell membrane, destroying the membrane integrity and causing leakage of intracellular substances, destroying the physical barrier. After compounding, it can reduce surface tension and enhance the permeability to microbial biofilms and organic pollutants. It can still maintain high efficiency in complex environments (containing protein interferents). In addition, the hydrophobicity of the double-chain quaternary ammonium salt can delay the decomposition of the single-chain quaternary ammonium salt and prolong the antibacterial effect time. The positive charge of the complex can neutralize the negative charge of the enzyme-cut starch, and the polar group can form hydrogen bonds with the hydroxyl group of the enzyme-cut starch, ensuring compatibility and dispersion stability with the enzyme-cut starch.

[0031] In addition, the present invention also provides a method for preparing a surface sizing agent for papermaking. Figure 1 , Figure 1 1 is a flow chart of an embodiment of a method for preparing a surface sizing agent for papermaking according to the present application, and the method includes but is not limited to the following steps.

[0032] In step S100 , a single-chain quaternary ammonium salt and a double-chain quaternary ammonium salt are placed in water according to a predetermined composition and stirred to prepare an antibacterial solution.

[0033] In this step, the mass ratio of the single-chain quaternary ammonium salt to the double-chain quaternary ammonium salt is between 3:4 and 4:3, and can specifically be a ratio of 3:4, 1:1, 4:3, etc. Wherein, the single-chain quaternary ammonium salt is selected from: any one or more of benzalkonium chloride, cetyltrimethylammonium chloride, and cetylpyridinium chloride. The double-chain quaternary ammonium salt is selected from: any one or more of bis-octyldimethylammonium chloride, bis-heptyldimethylammonium chloride, didodecyldimethylammonium chloride, cetylpyridinium chloride, dequalinium chloride, and benzethonium chloride.

[0034] Please continue reading Figure 1 The preparation method in this embodiment further includes step S200, preparing enzyme-cut starch glue.

[0035] In this step, see Figure 2 , Figure 2 This is a schematic diagram of an embodiment of the present invention for preparing an enzyme-cut starch glue solution, which includes but is not limited to the following steps.

[0036] Step S210: placing starch in water to obtain a starch solution.

[0037] The starch comprises corn starch or cassava starch or a mixture of the two. The solid content of the starch solution is 25±5%.

[0038] Step S220: using amylase to hydrolyze and modify the starch solution to obtain starch glue.

[0039] In step S220, the amylase includes either α-amylase or β-amylase or a mixture of the two.

[0040] Please continue reading Figure 1 The preparation method in this embodiment further includes step S300, adding the antibacterial agent solution to the enzyme-cut starch glue to obtain a surface sizing agent.

[0041] In this step, the absolute dry amount of the antibacterial solution added is 2-6% of the absolute dry amount of the enzyme-cut starch glue, and specifically can be 2%, 2.2%, 2.5%, 3%, 3.7%, 4%, 5%, 6% and the like.

[0042] Several specific embodiments are described below.

[0043] Example 1

[0044] 1. Preparation of composite antibacterial agent: Compound single-chain quaternary ammonium salt and double-chain quaternary ammonium salt according to the active component ratio of 3:4. Avoid the generation of bubbles during the compounding process (slightly stir and mix evenly).

[0045] 2. Preparation of enzymatic starch glue: corn or cassava starch was used to obtain a starch solution with a solid content of 25 ± 5%. The starch molecular chain was cut by enzyme at an enzyme dosage of 40 ppm. The glue viscosity was controlled to 80 cps. The storage temperature was 70°C. 15% (absolute dry weight) of triazine stilbene hexasulfonic acid fluorescent whitening agent and 8% (absolute dry weight) of sodium sulfate were added.

[0046] 3. Dilution of the enzyme-cut starch glue solution: dilute the enzyme-cut starch glue solution in step 2. After dilution, the solid content is 8% and the viscosity is 7 cps;

[0047] 4. Addition of composite antimicrobial agent: Add the composite antimicrobial agent solution of step 1 to the enzyme-cut starch glue of step 3, with the addition amount being 2% of the glue mass and the viscosity being 5 cps;

[0048] 5. Surface sizing on the machine: Use the antibacterial enzyme-cut starch glue from step 4 to sizing the paper, with a sizing amount of 1.5g / m 2 After drying and soft pressing, high-efficiency antibacterial cultural paper can be obtained, with a paper weight of 70g / m 2 .

[0049] Example 2

[0050] 1. Preparation of composite antimicrobial agent: Compound single-chain quaternary ammonium salt and double-chain quaternary ammonium salt according to the active components (absolute dry antimicrobial agent and absolute dry starch) in a ratio of 1:1. Avoid the generation of bubbles during the compounding process (stir gently and mix evenly).

[0051] 2. Preparation of enzymatic starch glue: corn and cassava starch were used to obtain a starch solution with a solid content of 25%. The starch molecular chains were cut by enzyme at an enzyme dosage of 50 ppm. The glue viscosity was controlled at 85 cps. The storage temperature was 70°C. 18% triazine stilbene hexasulfonic acid fluorescent whitening agent and 9% sodium sulfate were added.

[0052] 3. Dilution of the enzymatic starch glue: dilute the enzymatic starch glue from step 2. After dilution, the solid content is 9.0% and the viscosity is 8 cps;

[0053] 4. Addition of composite antimicrobial agent: Add the composite antimicrobial agent solution of step 1 to the enzyme-cut starch glue of step 3, with the addition amount being 4% of the glue mass and the viscosity being 6 cps;

[0054] 5. Surface sizing on the machine: Use the antibacterial enzyme-cut starch glue from step 4 to apply glue to the paper, with a glue amount of 2g / m 2 After drying and soft pressing, high-efficiency antibacterial cultural paper can be obtained, with a paper weight of 80g / m 2 .

[0055] Example 3

[0056] 1. Preparation of composite antimicrobial agent: Compound single-chain quaternary ammonium salt and double-chain quaternary ammonium salt according to the ratio of active components (absolute dry antimicrobial agent and absolute dry starch) of 4:3. Avoid bubbles during compounding (stir gently and mix evenly).

[0057] 2. Preparation of enzymatic starch glue: corn and cassava starch were used to obtain a starch solution with a solid content of 30%. The starch molecular chains were cut by enzyme at an enzyme dosage of 60 ppm. The glue viscosity was controlled at 90 cps. The storage temperature was 70°C. 20% triazine stilbene hexasulfonic acid fluorescent brightener and 10% sodium sulfate were added.

[0058] 3. Dilution of the enzymatic starch glue: dilute the enzymatic starch glue prepared in step 2. After dilution, the solid content is 10% and the viscosity is 10 cps.

[0059] 4. Addition of composite antimicrobial agent: Add the composite antimicrobial agent solution of step 1 to the enzyme-cut starch glue of step 3, with the addition amount being 6% of the glue mass and the viscosity being 8 cps;

[0060] 5. Surface sizing on the machine: Use the antibacterial enzyme-cut starch glue from step 4 to apply glue to the paper, with a glue amount of 2.5g / m 2 After drying and soft pressing, high-efficiency antibacterial cultural paper can be obtained, with a paper weight of 90g / m 2 .

[0061] The antimicrobial properties of the antimicrobial papers produced in the three examples above were tested according to national standards. The control sample was pure enzyme-cut starch-sized paper. Both the control and test samples were sterilized using autoclave. According to Section 5.6 of GB / T 42702-2023, Determination of Antimicrobial Properties of Paper, Paperboard, and Paper Products, the results were expressed as follows: an inhibition rate ≥50% indicates that the sample has an antimicrobial effect against the control sample, and an inhibition rate ≥90% indicates that the sample has a stronger antimicrobial effect than the control sample. Detailed test results are shown in the table below.

[0062]

[0063] Enzyme-cut starch is modified with a composite quaternary ammonium salt, forming hydrogen and ionic bonds with the hydroxyl and carboxyl groups of the enzyme-cut starch. This composite system exhibits excellent compatibility and dispersion stability. The composite antimicrobial agent significantly enhances the antimicrobial efficacy of enzyme-cut starch by disrupting the cell structure at multiple targets. Furthermore, it reduces the viscosity of the enzyme-cut starch, increases the drying rate of paper, reduces energy consumption, and improves sizing uniformity. The modified enzyme-cut starch is suitable for use on modern high-speed paper machines to produce antimicrobial cultural paper products.

[0064] In addition, the present invention also provides an antibacterial cultural paper, please refer to Figure 3 , Figure 3 This is a schematic diagram of the laminated structure of an embodiment of the antimicrobial cultural paper of the present application. Antimicrobial cultural paper 300 comprises base paper 310 and a surface sizing agent layer 320 coated on the surface of base paper 310. The formulation of surface sizing agent layer 320 is described in the aforementioned embodiments. Other parameter characteristics of the antimicrobial cultural paper are within the purview of those skilled in the art and are not further elaborated here.

[0065] The antibacterial cultural paper provided in the embodiments of the present application has the advantages of broad-spectrum bactericidal properties in the antibacterial agent solution in the surface sizing agent, is not easy to produce drug resistance to bacteria, has a stable alkaline environment, and does not contain heavy metals. Its positive charge can neutralize the negative charge of enzyme-cut starch, and the polar group can form hydrogen bonds with the hydroxyl groups of enzyme-cut starch, thereby enhancing the compatibility and dispersion stability of the composite system. The antibacterial agent solution can impart antibacterial properties to the enzyme-cut starch, and through multi-target destruction of the cell structure, achieve a significant improvement in the antibacterial effect, and effectively inhibit the production of bacteria and molds. The antibacterial agent solution is a low-volatile compound, suitable for a long-term and stable antibacterial environment, and will not undergo significant thermal decomposition under the high-temperature environment of the paper machine. In addition, it also reduces the viscosity of the enzyme-cut starch, increases the drying rate of the paper, reduces energy consumption, and improves the uniformity of sizing. The modified enzyme-cut starch is suitable for high-speed production of cultural paper on modern paper machines.

[0066] The above descriptions are only some embodiments of the present application and do not limit the scope of protection of the present application. Any equivalent device or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the scope of patent protection of this application.

Claims

1. An antibacterial solution, characterized in that The antibacterial agent solution comprises a single-chain quaternary ammonium salt, a double-chain quaternary ammonium salt and water.

2. The antibacterial solution according to claim 1, characterized in that The mass ratio of the single-chain quaternary ammonium salt to the double-chain quaternary ammonium salt is between 3:4 and 4:

3.

3. The antibacterial solution according to claim 2, characterized in that The mass ratio of the single-chain quaternary ammonium salt to the double-chain quaternary ammonium salt is 1:

1.

4. The antibacterial solution according to claim 1, characterized in that The single-chain quaternary ammonium salt is selected from any one or more of benzalkonium chloride, cetyltrimethylammonium chloride, and cetylpyridinium chloride.

5. The antibacterial solution according to claim 4, characterized in that The double-chain quaternary ammonium salt is selected from any one or more of bis-octyldimethylammonium chloride, bis-decyldimethylammonium chloride, didodecyldimethylammonium chloride, cetylpyridinium chloride, dequalinium chloride, and benzethonium chloride.

6. A method for preparing a surface sizing agent for papermaking, characterized in that: The preparation method comprises: The single-chain quaternary ammonium salt and the double-chain quaternary ammonium salt are placed in water according to predetermined components and stirred to prepare an antibacterial solution; preparing enzyme-cut starch glue solution; The antibacterial agent solution is added to the enzyme-cut starch glue to obtain a surface sizing agent.

7. The preparation method according to claim 6, characterized in that The step of preparing enzyme-cut starch glue comprises: placing starch in water to obtain a starch solution; wherein the starch comprises any one of corn starch and tapioca starch or a mixture of the two; The starch solution is hydrolyzed and modified by using amylase to obtain starch glue; wherein the amylase includes any one of α-amylase and β-amylase or a mixture of the two.

8. The preparation method according to claim 6, characterized in that In the step of adding the antibacterial agent solution to the enzyme-cut starch glue to obtain the surface sizing agent, the absolute dry amount of the antibacterial agent solution added is 2-6% of the absolute dry amount of the enzyme-cut starch glue.

9. A surface sizing agent for papermaking, characterized in that: The surface sizing agent is prepared by the preparation method according to any one of claims 6 to 8. 10.An antibacterial cultural paper, characterized in that: The surface of the antibacterial cultural paper is provided with the surface sizing agent according to claim 9.

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