Paper adhesive selection method

Abstract

The invention provides a paper adhesive selection method which comprises the following steps: S1, acquiring first to-be-detected paper, and performing liquid dropping treatment on the first to-be-detected paper; s2, measuring the first to-be-measured paper and the liquid according to the contact position of the first to-be-measured paper and the liquid to obtain contact angle information of the first to-be-measured paper and the liquid; and S3, according to the contact angle information, a target paper adhesive is determined, and the target paper adhesive is represented as a polar adhesive or a non-polar adhesive. By accurately measuring the contact angle parameter of the paper and the liquid, the adhesive highly matched with the characteristics of the paper can be screened out in a targeted manner, so that the bonding strength of the paper is remarkably improved. By means of driving analysis of contact angle data, the optimal adhesive selection can be accurately positioned, the bonding process matched with the optimal adhesive selection can be designed in a customized mode, the test period is effectively shortened, the process adjusting cost is reduced, and the production efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of paper adhesives, and in particular to a method for selecting a paper adhesive. Background Art

[0002] In today's wide range of paper processing and applications, the bonding between paper and adhesives plays a crucial role in the quality of the final product. Paper, as an extremely common material, is widely used in numerous industries, including packaging, printing, and stationery. The primary function of adhesives is to firmly bond paper to various other materials.

[0003] In practical applications, bond strength and uniformity are considered key indicators of bonding effectiveness. Bond strength directly determines the stability of the connection between paper and other materials, while bond uniformity affects the smoothness of the product's appearance and the consistency of its overall performance.

[0004] However, the bonding of paper and adhesives currently faces a pressing challenge. The paper surface has unique polarity properties, and the adhesive also possesses its own polarity. When the polarity mismatches between the two, insufficient bond strength frequently occurs, resulting in a weak connection between the paper and the other material and the tendency for separation during use. Furthermore, this polarity mismatch can lead to uneven bonding, resulting in localized excess or insufficient strength at the bonded area, compromising the overall quality and aesthetics of the product. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a method for selecting paper adhesives to solve the above problems.

[0006] In order to solve the above technical problems, this application adopts the following technical solutions:

[0007] The present application provides a paper adhesive selection method, which includes: step S1: obtaining a first paper to be tested and performing a liquid drop treatment on the first paper to be tested; step S2: measuring the first paper to be tested and the liquid based on the contact position between the first paper to be tested and the liquid to obtain contact angle information of the first paper to be tested and the liquid; step S3: determining a target paper adhesive based on the contact angle information, wherein the target paper adhesive is characterized as a polar adhesive or a non-polar adhesive.

[0008] Furthermore, step S2 includes: step S21: measuring the first paper to be tested and the liquid using a contact angle meter and / or a surface energy meter to obtain contact angle information between the first paper to be tested and the liquid.

[0009] Furthermore, step S3 includes: step A31: determining whether the contact angle information is greater than a preset contact angle threshold; if so, determining that the first paper to be tested is hydrophilic paper; step A32: determining whether the first paper to be tested is hydrophilic paper; if so, selecting the target paper adhesive as a polar adhesive.

[0010] Furthermore, step S3 includes: step B31: determining whether the contact angle information is less than a preset contact angle threshold; if so, determining that the first paper to be tested is hydrophobic paper; step B32: determining whether the first paper to be tested is hydrophobic paper; if so, selecting the target paper adhesive as a non-polar adhesive.

[0011] Furthermore, the polar adhesive includes at least one of the following: polyvinyl alcohol adhesive, polyacrylate adhesive and polyvinyl aldehyde adhesive.

[0012] Furthermore, the non-polar adhesive includes at least one of the following: hot melt adhesive, silicone adhesive, polyethylene adhesive and polyurethane hot melt adhesive.

[0013] Furthermore, the paper adhesive selection method further includes: step S4: performing bonding processing on the first paper to be tested according to the target paper adhesive to obtain strength test paper; step S5: performing bonding strength testing on the strength test paper to determine the bonding effect of the target paper adhesive.

[0014] Furthermore, step S4 includes: step S41: evenly applying the target paper adhesive on the bonding area of the first paper to be tested; step S42: aligning the second paper to be tested with the bonding area, and applying pressure to the second paper to be tested so that the second paper to be tested is bonded to the first paper to be tested, thereby obtaining strength test paper.

[0015] Furthermore, step S5 includes: step S51: fixing the two ends of the strength test paper on the clamping mechanism of the tensile testing machine respectively; step S52: starting the tensile testing machine, and the clamping mechanism pulls the two ends of the strength test paper apart from each other according to a preset fixed speed, and records the maximum tensile force value; step S53: determining the bonding effect of the target paper adhesive based on the maximum tensile force value.

[0016] Adhesive refers to a class of natural or synthetic, organic or inorganic substances that can connect two or more parts or materials together through interfacial adhesion and cohesion. Polarity parameters refer to numerical values that reflect the charge distribution characteristics of the material surface, such as surface free energy. The bonding process refers to the process of applying the adhesive to the surface of the material to be bonded, compacting it, and curing it. A polarity detector refers to an instrument used to measure the polarity characteristics of the material surface. Surface free energy refers to the energy formed on the surface of the material due to intermolecular interactions, and its unit is mN / m (millinewtons per meter). The contact angle refers to the angle formed by a droplet on a solid surface and is used to evaluate the surface wettability. A tensile testing machine refers to a device used to test the tensile strength of a material.

[0017] As can be seen from the above technical solutions, the advantages and positive effects of the paper adhesive selection method proposed in this application are:

[0018] This application proposes an innovative method for screening paper adhesives based on contact angle measurements. By precisely measuring the contact angle parameters between paper and liquid, adhesives that are highly compatible with the paper's properties can be specifically screened, significantly improving the paper's bonding strength. Driven by analysis based on contact angle data, not only can the optimal adhesive be precisely identified, but also a customized bonding process can be designed to match it. This effectively shortens testing cycles, reduces process adjustment costs, and significantly improves production efficiency.

[0019] To ensure reliable bonding quality, this application established a standardized paper tensile strength testing system. By combining biaxial tensile testing, which simulates actual usage scenarios, and combining quantitative evaluation indicators, this method enables high-precision testing of bonding effectiveness. This method not only ensures product quality stability but also provides data support for process optimization, forming a complete technical closed loop from material screening to process verification.

[0020] This invention's technological breakthrough lies in systematically advancing paper bonding technology through collaborative innovation across materials, processes, and testing, providing an innovative, efficient, and reliable solution for the packaging, printing, and other related industries. This technological achievement not only holds significant value for technical protection but also demonstrates broad application prospects in areas such as intelligent manufacturing and green packaging, potentially driving the upgrading and iteration of industry technical standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above content of this application and the following specific embodiments will be better understood when read in conjunction with the accompanying drawings. It should be noted that the accompanying drawings are only examples of the technical solutions claimed.

[0022] Figure 1 is a flow chart of the paper adhesive selection method provided by this application;

[0023] Figure 2This is a schematic diagram of a test of a strength test paper by a tensile testing machine according to the first embodiment of the present application;

[0024] Figure 3 This is a schematic diagram of a test of a strength test paper by a tensile testing machine according to the second embodiment of the present application.

[0025] The description of the accompanying drawings is as follows:

[0026] Clamp: 1;

[0027] Strength test paper: 2. DETAILED DESCRIPTION

[0028] The detailed features and advantages of the present application are described in detail below in the specific implementation methods, and the content is sufficient to enable any technical personnel in this field to understand the technical content of the present application and implement it accordingly. Based on the description, claims and drawings disclosed in this specification, technical personnel in this field can easily understand the relevant purposes and advantages of the present application.

[0029] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0030] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product is usually placed when in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0031] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0032] Please refer to Figure 1 The present application provides a method for selecting a paper adhesive, which may specifically include the following steps:

[0033] Step S1: obtaining a first paper to be tested, and performing a liquid dripping process on the first paper to be tested.

[0034] For example, a sample of the first paper to be tested is cut into an appropriate size to ensure that the surface of the sample is clean and free of contamination. The liquid can be a common liquid such as water, and a small drop of water is dropped on the surface of the first paper to be tested.

[0035] Step S2: measuring the first paper to be tested and the liquid according to the contact position between the first paper to be tested and the liquid to obtain contact angle information between the first paper to be tested and the liquid.

[0036] Specifically, the contact angle information of the first paper to be tested and the liquid can be obtained by measuring the contact angle between the first paper to be tested and the liquid using a contact angle meter and / or a surface energy meter.

[0037] It can be understood that a small drop of water is dropped on the surface of the sample and the contact angle is measured using a contact angle meter or a surface energy meter to obtain information on the size of the contact angle.

[0038] For example, the contact angle may be detected using a Krüss K100 fully automatic surface tensiometer, which integrates the functions of a contact angle meter and a surface energy meter.

[0039] Step S3: determining a target paper adhesive based on the contact angle information, wherein the target paper adhesive is characterized as a polar adhesive or a non-polar adhesive.

[0040] Specifically, step S3 includes: step A31: determining whether the contact angle information is greater than a preset contact angle threshold; if so, determining that the first paper to be tested is hydrophilic paper; step A32: determining whether the first paper to be tested is hydrophilic paper; if so, selecting the target paper adhesive as a polar adhesive.

[0041] Step S3 includes: Step B31: determining whether the contact angle information is less than a preset contact angle threshold; if so, determining that the first paper to be tested is hydrophobic paper; Step B32: determining whether the first paper to be tested is hydrophobic paper; if so, selecting the target paper adhesive as a non-polar adhesive.

[0042] For example, the preset contact angle threshold can be 90°. If the contact angle between the first paper to be tested and the liquid is less than 90°, it indicates that the first paper to be tested is hydrophilic; if the contact angle between the first paper to be tested and the liquid is greater than 90°, it indicates that the first paper to be tested is hydrophobic.

[0043] The target paper adhesive is determined based on the hydrophilicity and hydrophobicity of the first paper to be tested. For example, the polar adhesive corresponding to the hydrophilic paper may be polyvinyl alcohol adhesive, polyacrylate adhesive, or polyvinyl aldehyde adhesive.

[0044] Polyvinyl alcohol adhesives are made primarily from polyvinyl alcohol (PVA). Polyvinyl alcohol is a synthetic polymer that is odorless, non-toxic, and water-soluble, appearing as a yellow or white powder. Polyvinyl alcohol adhesives offer strong adhesion, form tough films, are inexpensive, and are easy to prepare. However, high-solids solutions are difficult to prepare and cure slowly.

[0045] Polyacrylate adhesives are made by copolymerizing (meth)acrylate monomers. They offer a wide range of design options for their molecular chain structure, allowing for a variety of soft and hard materials. These adhesives offer advantages such as weather resistance, aging resistance, and high bond strength.

[0046] Polyvinyl acetal adhesives are formed by the polycondensation of polyvinyl alcohol (PVA) and aldehydes under acidic conditions. Their performance depends on the molecular weight and degree of alcoholysis of the PVA, the chemical structure of the aldehyde used, and the extent of the acetalization reaction. Polyvinyl acetal adhesives exhibit excellent toughness, light resistance, and moisture resistance.

[0047] The non-polar adhesives corresponding to hydrophobic paper can be hot melt adhesive, silicone adhesive, polyethylene adhesive and polyurethane hot melt adhesive.

[0048] Hot melt adhesive is a plastic adhesive primarily composed of EVA resin, a copolymer of ethylene and vinyl acetate under high temperature and pressure. It is solid at room temperature but becomes a flowable, viscous liquid when heated and melted to a certain temperature. Hot melt adhesive offers advantages such as fast curing, pollution-free, non-toxic, and odorless properties, as well as ease of packaging, transportation, and storage.

[0049] Silicone adhesive is a high-grade adhesive and sealing material made from a hydroxyl-terminated siloxane polymer and a multifunctional siloxane crosslinker, supplemented with plasticizers, reinforcing agents, and other auxiliary materials. Upon exposure to moisture in the air, it solidifies into a tough, rubbery solid. Silicone adhesive exhibits strong adhesion, high tensile strength, weather resistance, and high and low temperature resistance.

[0050] Polyethylene adhesive is a glue used for bonding and sealing. Its primary ingredient is ethyl cyanoacrylate. It undergoes an addition polymerization reaction catalyzed by trace amounts of water in the air, rapidly curing and securing the adherends. Polyethylene adhesives are specialized for fast and perfect bonding between PE and PE, as well as between PE and various materials, including plastics, metals, wood, ceramics, stone, and rubber.

[0051] Polyurethane hot melt adhesive (PUR) is a moisture-curing reactive hot melt adhesive primarily composed of an isocyanate-terminated polyurethane prepolymer. PUR hot melt adhesive exhibits excellent bonding strength, temperature resistance, chemical resistance, and aging resistance. Its adhesiveness and toughness can be adjusted, demonstrating excellent adhesion to a wide range of materials.

[0052] In an embodiment of the present application, an information database containing various paper adhesives can be established, and the adhesives can be classified according to their characteristics in the information database. After the central control system, processor and other devices obtain the contact angle information of the contact between paper and liquid, the target paper adhesive can be selected from the information database based on the contact angle information.

[0053] After determining the target paper adhesive, the paper adhesive selection method also includes:

[0054] Step S4: performing a bonding process on the first paper to be tested according to the target paper adhesive to obtain strength test paper.

[0055] Step S4 includes: step S41: evenly coating the target paper adhesive on the bonding area of the first paper to be tested; step S42: aligning the second paper to be tested with the bonding area, and applying pressure to the second paper to be tested so that the second paper to be tested is bonded to the first paper to be tested, thereby obtaining strength test paper.

[0056] For example, the target paper adhesive must be precisely and evenly applied to the intended bonding area of the first test paper. The coating process is strictly controlled to ensure a uniform adhesive layer thickness (within 50-100 microns) and to eliminate bubbles and voids. This step aims to create a homogeneous bonding interface, fundamentally eliminating test errors caused by uneven adhesive distribution.

[0057] Next, the second test paper is precisely aligned with the adhesive-coated area of the first test paper, achieving seamless bonding between the two sheets through precise alignment. Controlled pressure (0.5-1.0 MPa) is then applied and maintained for several seconds to promote sufficient infiltration and interfacial bonding between the adhesive molecules. Finally, a standardized curing process is performed according to the adhesive's curing process parameters to ensure complete crosslinking and hardening of the adhesive system, ultimately forming a strength test paper with stable mechanical properties.

[0058] A stable bonding interface is formed between the first paper to be tested and the second paper to be tested, providing a reliable basis for subsequent tests.

[0059] It is understood that, depending on the properties of the adhesive, appropriate curing conditions (such as temperature and time) can be set to ensure that the bonding interface is fully cured. For example, polar adhesives can be cured at room temperature, while non-polar adhesives such as hot melt adhesives require heating to cure.

[0060] Step S5: performing a bonding strength test on the strength test paper to determine the bonding effect of the adhesive on the target paper.

[0061] Step S5 includes: Step S51: securing the two ends of the strength test paper to the clamping mechanism of the tensile testing machine. Step S52: activating the tensile testing machine, causing the clamping mechanism to pull the two ends of the strength test paper apart at a preset fixed speed, and recording the maximum tensile force. Step S53: determining the bonding effect of the adhesive on the target paper based on the maximum tensile force.

[0062] For example, please refer to Figure 2 and Figure 3After the strength test paper is cured, fix the strength test paper 2 to the two clamps 1 of the tensile testing machine and pull them apart at a constant speed. During the pull-apart test, apply a uniform tensile force and record the maximum tensile force as the bonding strength data.

[0063] It is understandable that in the prior art, the bonding effect of adhesives is usually measured by tearing and shearing.

[0064] Among them, the tearing test is a common bonding strength test method. The bonding strength is evaluated by tearing two pieces of paper together with force and measuring the maximum force during the tearing process.

[0065] This method is simple and easy to use, but because the distribution of the adhesive in the bonding area may be uneven, the test results may fluctuate greatly and are not stable enough.

[0066] The shear test measures the bond strength by applying a force parallel to the bonding surface, causing shear failure at the bonding interface.

[0067] The shear test can reflect the overall strength of the bonding interface, but the problem of uneven force still exists during the test.

[0068] As shown in Table 1, this application innovatively employs a bilateral tensile test method. By uniformly applying tension, this method effectively avoids test data deviations caused by uneven local distribution of the adhesive, significantly improving the stability and reliability of the test results. This bidirectional force mechanism enables a more comprehensive assessment of the mechanical properties of the bonding interface, ensuring that the measured data truly reflects the intrinsic properties of the material.

[0069] Table 1: Test results of paper double-sided stretching

[0070]

[0071]

[0072] It should be noted that this application pioneers a paper adhesive screening technology based on precise contact angle measurement. By systematically measuring the contact angle characteristic parameters between the paper surface and the test liquid, it can efficiently identify adhesive systems that precisely match the physical and chemical properties of the paper, significantly improving the mechanical strength of the paper bonding interface. Relying on in-depth analysis of contact angle data, this technology not only enables intelligent optimization of adhesive formulations but also enables the simultaneous development of customized bonding process solutions, effectively shortening the R&D cycle, reducing process debugging costs, and promoting a qualitative leap in production efficiency.

[0073] This application also innovatively developed a standardized method for assessing paper bonding strength. By combining bidirectional dynamic tensile testing that simulates real-world operating conditions with multi-dimensional quantitative evaluation indicators, high-precision characterization of bonding performance was achieved. This technical system not only ensures the continued stability of product quality but also provides reliable data support for iterative process optimization. It successfully establishes a complete technical closed loop from material screening to process verification, providing an innovative solution for the intelligent upgrade of paper bonding technology.

[0074] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0075] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0076] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0077] The terms and expressions used herein are for descriptive purposes only, and this application is not intended to be limited to these terms and expressions. The use of these terms and expressions does not exclude any equivalent features of the features illustrated and described (or portions thereof), and it should be recognized that various modifications that may exist are also intended to be included within the scope of the claims. Other modifications, variations, and substitutions are also possible. Accordingly, the claims should be deemed to cover all such equivalents.

[0078] Similarly, it should be pointed out that although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should realize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions can be made without departing from the spirit of the invention. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A method for selecting a paper adhesive, characterized in that: The paper adhesive selection method comprises: Step S1: obtaining a first paper to be tested, and performing a liquid dripping process on the first paper to be tested; Step S2: measuring the first paper to be tested and the liquid according to the contact position between the first paper to be tested and the liquid to obtain contact angle information between the first paper to be tested and the liquid; Step S3: determining a target paper adhesive based on the contact angle information, wherein the target paper adhesive is characterized as a polar adhesive or a non-polar adhesive.

2. The paper adhesive selection method according to claim 1, characterized in that: The step S2 comprises: Step S21: measuring the first paper to be tested and the liquid using a contact angle meter and / or a surface energy meter to obtain contact angle information between the first paper to be tested and the liquid.

3. The paper adhesive selection method according to claim 1, characterized in that: The step S3 comprises: Step A31: determining whether the contact angle information is greater than a preset contact angle threshold; if so, determining that the first paper to be tested is hydrophilic paper; Step A32: determining whether the first paper to be tested is the hydrophilic paper; if so, selecting the target paper adhesive as the polar adhesive.

4. The paper adhesive selection method according to claim 1, characterized in that: The step S3 comprises: Step B31: determining whether the contact angle information is less than a preset contact angle threshold; if so, determining that the first paper to be tested is hydrophobic paper; Step B32: determining whether the first paper to be tested is the hydrophobic paper; if so, selecting the target paper adhesive as the non-polar adhesive.

5. The paper adhesive selection method according to claim 1, characterized in that: The polar adhesive includes at least one of the following: polyvinyl alcohol adhesive, polyacrylate adhesive and polyvinyl aldehyde adhesive.

6. The paper adhesive selection method according to claim 1, characterized in that: The non-polar adhesive includes at least one of the following: hot melt adhesive, silicone adhesive, polyethylene adhesive and polyurethane hot melt adhesive.

7. The paper adhesive selection method according to claim 1, characterized in that: The paper adhesive selection method further comprises: Step S4: performing a bonding process on the first paper to be tested according to the target paper adhesive to obtain strength test paper; Step S5: performing a bonding strength test on the strength test paper to determine the bonding effect of the adhesive on the target paper.

8. The paper adhesive selection method according to claim 7, characterized in that: The step S4 comprises: Step S41: evenly coating the target paper adhesive on the bonding area of the first paper to be tested; Step S42: aligning a second paper to be tested with the bonding area, and applying pressure to the second paper to be tested so that the second paper to be tested is bonded to the first paper to be tested, thereby obtaining the strength test paper.

9. The paper adhesive selection method according to claim 7, characterized in that: The step S5 comprises: Step S51: fixing the two ends of the strength test paper on the clamping mechanism of the tensile testing machine respectively; Step S52: starting the tensile testing machine, and the clamping mechanism pulls the two ends of the strength test paper apart from each other at a preset fixed speed, and records the maximum tensile force value; Step S53: determining the bonding effect of the target paper adhesive according to the maximum tension value.

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