CN116536964A - Preparation method of multilayer laminated paper and multilayer laminated paper - Google Patents

Abstract

The application provides a preparation method of multilayer laminated paper and the multilayer laminated paper, and relates to the technical field of papermaking. The preparation method of the multilayer laminated paper comprises the steps of spraying starch solution and latex with a Tg value not more than 2 and not less than-2 on the surfaces to be combined of the multilayer formed paper, laminating the sprayed multilayer formed paper, carrying out multiple combined pressing, and drying the paper subjected to combined pressing to obtain the multilayer laminated paper. According to the method, the starch solution and the latex are sprayed, so that the multi-layer forming paper has higher cohesive force after lamination, the latex with the Tg value not more than 2 and not less than-2 is selected to improve the flexibility of the dried multi-layer laminating paper, and the multi-layer combination squeezing can improve the tightness of the paper formed by lamination, so that the effect of improving the interlayer bonding strength of the multi-layer laminating paper is achieved.

Description

Preparation method of multi-layer laminated paper and multi-layer laminated paper

technical field

The present application relates to the technical field of papermaking, in particular to a method for preparing multilayer laminated paper and the multilayer laminated paper.

Background technique

Multi-layer laminated paper is a multi-layer laminated structure with a high grammage. It can be used as a positioning substrate for electronic devices, dinner plate paper, paper for Lego product production, etc., and plays a role in many fields. Taking the positioning substrate of electronic devices as an example, chip capacitors (MLCC) need to have substrate positioning when they are assembled on the motherboard. The traditional plastic products for positioning the substrate, but with the miniaturization of MLCC products, plastic products are used as When positioning substrates for small-sized MLCC products, it is difficult to round the corners of punched holes, and plastic products are prone to static electricity problems, which will absorb these smaller and smaller electronic MLCC products, so plastic products are gradually being replaced by more and more heavy-weight products. Laminated paper instead.

Multi-layer laminated paper often needs to be processed during application, such as punching, punching, etc., which has higher requirements for the interlayer bonding strength of multi-layer laminated paper. The inter-layer bonding of related multi-layer laminated paper is usually achieved by the combination of hydroxyl groups of fiber pulp and spraying starch between layers, but this method can only meet the requirements of multi-layer laminated paper with relatively low grammage. The grammage of the multilayer laminated paper is relatively high, for example, when the grammage is greater than 600g/m ² , the above method is not enough to make the multilayer laminated paper have a sufficiently high interlayer bonding strength, which will easily lead to the high grammage of the multilayer laminated paper. Delamination occurs during processing, and the delaminated multi-layer laminated paper is likely to cause other problems when used. For example, when filling MLCC products, these MLCC products may be caught in the delamination and cannot be used.

Contents of the invention

The technical problem mainly solved by this application is how to improve the bonding strength between layers of laminated paper.

In order to solve the above technical problems, a technical solution adopted by the present application is to provide a method for preparing multi-layer laminated paper, including:

Perform beating and pulping to obtain the pulp required for papermaking;

Send the pulp to multiple paper nets of the paper machine to dehydrate and form the pulp to obtain multi-layer formed paper;

Spray the spray agent on the surface to be bonded of the multi-layer forming paper, the spray agent includes starch liquid and latex, and the Tg value of the latex is not greater than 2 and not less than -2;

Stack the sprayed multi-layer molding paper and perform multi-channel combined pressing;

Dry the combined pressed paper to obtain multi-layer laminated paper.

In some embodiments, the latex is any one of acrylic latex, nitrile latex, carboxylated styrene-butadiene latex, and styrene-acrylic latex.

In some embodiments, the spray amount of latex is 3.0kg-3.5kg per ton of paper.

In some embodiments, the preparation process of starch liquid comprises:

mixing raw starch with water to form a starch solution with a concentration of 1%-10%;

The starch solution is gelatinized into starch liquid at 90°C-100°C.

In some embodiments, the spray amount of the starch liquid is 30kg-35kg per ton of paper.

In some embodiments, in the step of performing multiple combined pressing, the tightness of the paper is pressed to not less than 0.9 g/m ³ .

In some embodiments, during the step of performing multi-pass combined pressing, the pressure of the multi-pass pressed tends to increase gradually.

In some embodiments, the grammage of each layer of forming paper is controlled within the range of 85g/m ² -95g/m ²

In some embodiments, the steps of beating and pulping include:

Use a conical refiner for the first stage of beating to separate the fibers in the pulp into filaments;

A single-disk mill beater is used for the second stage of beating, and beating aids are added during the second stage of beating, so that the beating aids can fully contact the fibers.

In some embodiments, the beating concentration of the first stage of beating is 8%-12%, and the beating degree is 20°SR-30°SR; the beating concentration of the second stage beating is 3%-5%, and the beating degree is 38° For SR-42°SR, the amount of beating aid added is 10%-20% of the absolute dry mass of the fiber.

In some embodiments, the steps of beating and pulping further include: after the second stage of beating is completed, adding starch in the pulp and a wet strength agent, the starch in the pulp is added in an amount of 6kg-15kg per ton of paper, and the wet strength agent Add in an amount of 1kg-2kg per ton of paper to dilute the slurry concentration to 1%-2%; then add alkyl ketene dimer in an amount of 20kg-35kg per ton of paper.

In order to solve the above technical problems, another technical solution adopted by the present application is to provide a multi-layer laminated paper, which is produced by the above-mentioned preparation method of the multi-layer laminated paper.

Different from the prior art, the preparation method of the multi-layer laminated paper provided by the present application and the beneficial effects of the multi-layer laminated paper are:

In this application, starch liquid and latex with a Tg value not greater than 2 and not less than -2 are sprayed on the surface of the multi-layer forming paper to be bonded, and then the sprayed multi-layer forming paper is stacked and multi-channel combined pressing is carried out. Then dry the combined and pressed paper to obtain multi-layer laminated paper; among them, spraying starch liquid and latex can make the multi-layer formed paper have higher cohesion after lamination, and the selected Tg value is not greater than 2 and not less than - The latex of 2 can improve the flexibility of the multi-layer laminated paper after drying, and the multi-pass combined pressing can increase the tightness of the laminated paper, thereby achieving the effect of improving the interlayer bonding strength of the multi-layer laminated paper.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following will briefly introduce the drawings that are used in the embodiments. Apparently, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative efforts.

Fig. 1 is a schematic flow chart of the preparation method of multi-layer laminated paper provided by some embodiments of the present application;

Fig. 2 is a schematic diagram of the beating process provided by some embodiments of the present application;

Fig. 3 is a schematic flow chart of the preparation method of multi-layer laminated paper provided by some embodiments of the present application;

Fig. 4 is a schematic structural view of a multi-layer laminated paper provided by some embodiments of the present application.

Detailed ways

In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

In order to make the above purpose, features and advantages of the present application more obvious and understandable, the specific implementation manners of the present application will be described in detail below in conjunction with the accompanying drawings. It should be understood that the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

It should be understood that the terms "comprising", "comprising", "having" and any variations thereof used in the specification and appended claims of this application are intended to cover a non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes unlisted steps or units, or optionally further includes For other steps or units inherent in these processes, methods, products or apparatuses.

The application provides a method for preparing multilayer laminated paper.

Please refer to FIG. 1 . FIG. 1 is a schematic flowchart of a method for preparing multi-layer laminated paper provided in some embodiments of the present application.

The preparation method of multi-layer laminated paper comprises:

S11, beating and blending.

Perform beating and pulping to obtain the pulp required for papermaking. Wherein, pulp for beating may include bleached kraft softwood and kraft bleached hardwood. The fiber length of coniferous wood is longer (2-4mm), which can provide sufficient strength for paper, while the fiber length of hardwood wood is shorter (less than 1mm), which can make paper have better surface touch and softness. By using softwood pulp and The combination of hardwood pulp can meet the requirements of different products.

Optionally, take 10-30 parts of sulfate bleached coniferous wood, such as 15 parts, 20 parts, 25 parts, etc., and take 70-90 parts of sulfate bleached hardwood, such as 75 parts, 80 parts, 85 parts, etc., and mix beating.

Some embodiments may adopt a segmented beating method. Please refer to FIG. 2 . FIG. 2 is a schematic diagram of a beating process provided by some embodiments of the present application.

The beating process includes:

S21, the first stage of beating.

In the first beating process, the beating concentration can be controlled at 8%-12%, such as 9%, 10%, 11% and so on. The beating consistency refers to the concentration of pulp in water during beating. In this section of beating, a conical refiner can be used to beat the above mixed pulp to 20°SR-30°SR, such as 21°SR, 23°SR, 25°SR, 27°SR, 29°SR, etc. The fibers are divided into filaments.

Among them, "°SR" is the unit of beating degree, also known as beating degree, which is one of the indicators to measure the quality of pulp. It can indicate the degree of pulp drainage when making paper online.

S22, the second stage of beating.

The second stage of beating is carried out after the first stage of beating is completed. In the second beating process, the beating concentration can be controlled at 3%-5%, such as 3.5%, 4%, 4.5% and so on. In the second beating process, a beating aid is added, and the amount of the beating aid is 10%-20% of the absolute dry mass of the pulp fiber, such as 12%, 14%, 16%, 18%, etc. The beating aid can be alkali, surfactant, CMC, modified lignin, etc., and any one or several of them can be selected according to the requirements of paper making. For example, caustic soda and sodium phosphate can be used as beating aids to improve paper strength.

In the second stage of beating, a disc refiner and beater can be used for beating, so as to ensure that the beating aid can fully contact the pulp limit. The beating degree of the second stage of beating is controlled at 38°SR-42°SR, such as 39°SR, 40°SR, 41°SR, etc.

Beating is the process of processing pulp fibers. Through mechanical action, the fibers are rubbed and rubbed against each other, and the thick and long fibers are cut short, crushed and divided into filaments to achieve a certain beating degree, wet weight, hydration degree and strength, etc. Index, which is beneficial to greatly increase the external specific surface area of the fiber, so that the rigidity of the fiber decreases, the elasticity is weakened, the plasticity is increased, the fiber becomes softer and more plastic, and it can also expose more hydroxyl groups in the fiber molecular chain, which promotes The formation of hydrogen bonds between fibers makes the pulp more suitable for different performance requirements of paper. The beating process and strength of paper play a very important role in the toughness, burst resistance and tear resistance of paper.

In the embodiment of the present application, by using a conical refiner and a disc refiner to perform two-stage beating, the degree of fibrous separation of pulp fibers can be improved, which is beneficial to improving the quality of paper. It should be noted that in other embodiments of the present application, the beating can also be designed in a single-stage or more than two-stage manner, and each stage of beating can use equipment with corresponding characteristics as required, and is not limited to this embodiment.

Please continue with Figure 1. The pulp is mixed after beating, and an appropriate amount of additives can be added to the pulp during the pulping process to improve the strength of the paper.

Specifically, after the second stage of beating is completed, starch in the slurry and a wet strength agent can be added to the slurry. Wherein, the starch in pulp can be cationic oxidized starch. The starch in the pulp (absolutely dry pulp) can be added in an amount of 6kg-15kg per ton of paper, such as 7kg/t, 9kg/t, 11kg/t, 13kg/t, etc. The wet strength agent can form a cross-linked, water-insoluble and covalent bond network structure with cellulose and hemicellulose, so that the paper can still maintain a high strength in a wet state. It can be formaldehyde resin, polyamide epoxy chloride Propane resin, polyethyleneimine, etc. Wet strength agent (absolutely dry pulp) can be added in an amount of 1kg-2kg per ton of paper, such as 1.2kg/t, 1.4kg/t, 1.6kg/t, 1.8kg/t, etc.

The addition amount of starch and wet strength agent in the slurry can be adjusted appropriately according to the situation, so as to dilute the slurry concentration to 1%-2%. After dilution, add alkyl ketene dimer (AKD) at an amount of 20kg-35kg per ton of paper, such as 23kg/t, 26kg/t, 29kg/t, 32kg/t, etc., to further increase the paper strength .

After beating and pulping, the obtained slurry can be degassed and defoamed, and then finely screened to obtain pulp that can be used for papermaking. Degassing and defoaming can be achieved by using mechanical equipment (such as degassing tank, degasser) or adding chemicals (such as degassing agent, defoaming agent) to the pulp or both to remove the air in the pulp. Fine screening can be done with corresponding pulp screening equipment.

S12. Paper molding.

After the pulp that can be used for papermaking is obtained, papermaking equipment can be used to make molding paper. Specifically, the pulp is sent to multiple paper wires of the paper machine respectively, and the pulp is dehydrated and shaped to obtain multi-layer molded paper. For example, the pulp is sprayed onto a plurality of cylinders of a cylinder paper machine to form a multi-layer forming paper.

Among them, the number of paper webs of the paper machine determines the number of layers of the final multi-layer laminated paper. The number of paper webs of the paper machine used in this application is two or more, including but not limited to three, five, Seven, ten, etc., the more the number of forming paper, the more layers of laminated paper made by lamination, and the heavier the weight.

S13. Spray additives.

The multi-layer forming paper will be laminated in the subsequent preparation process to form a multi-layer laminated paper. In order to ensure that the multi-layer laminated paper has a sufficiently high interlayer bonding strength to avoid delamination during processing, the embodiment of the present application is made in the forming paper After the preparation, the spraying agent is sprayed on the surface of the multi-layer molding paper to be bonded, so as to improve the bonding strength of the multi-layer molding paper after lamination. It should be noted that the surface to be bonded refers to the surface of the forming paper used to combine with other forming papers to form a multi-layer laminated paper. The spray liquid can be evenly sprayed onto the surface to be bonded of each layer of forming paper.

The spray agent provided in the embodiment of the present application includes starch liquid and latex. Wherein, the starch solution is composed of raw starch and water. The preparation process of the starch liquid includes: mixing the original starch and water into a starch solution with a concentration of 1%-10%, such as 3%, 5%, 7% and so on; °C, 95 °C, 97 °C, 99 °C, etc., the starch solution is gelatinized into starch liquid.

Among them, raw starch refers to all kinds of starch produced without any chemical treatment and without changing the inherent physical and chemical properties of starch; gelatinization refers to the phenomenon that starch forms a uniform paste after being heated. After gelatinization, starch The viscosity will increase sharply.

The applicant's research found that spraying the starch solution formed by gelatinization of a starch solution with a concentration of 1%-10% at 90°C-100°C onto the surface to be bonded of the forming paper can effectively improve the quality of the multi-layer laminated paper produced. interlayer bonding strength.

The requirement for the selection of latex is that the Tg value is not greater than 2 and not less than -2, for example, the Tg value is -1, the Tg value is 0, the Tg value is 1, etc. The Tg value refers to the glass transition temperature. The applicant found that Tg The latex with a value within this range can improve the flexibility of the formed paper after drying after it is made into a spray agent and sprayed onto the surface of the formed paper to be bonded.

Among them, the latex can adopt different types of water-based latex. The selection of latex can also refer to its bonding performance. Further research by the applicant has found that acrylic latex, nitrile latex, carboxylated styrene-butadiene latex and styrene-acrylic latex with Tg values within the above range can meet the requirements.

Among them, carboxylated styrene-butadiene latex is a copolymer produced by emulsion polymerization with butadiene, styrene and a small amount of carboxylic acid and other additives. It is a water dispersion with high cohesive force and conjunctival strength. It has good chemical stability, good fluidity and storage stability, and large filling capacity. The residual benzene monomer is very small, and it is an environmentally friendly product.

Nitrile latex is prepared by copolymerization of butadiene and acrylonitrile emulsion. Since the molecular chain of the copolymer contains nitrile groups, it has good oil resistance, solvent resistance and chemical resistance, and has good adhesion to fibers and has good adhesion to starch. Good compatibility.

Styrene-acrylic latex is obtained by emulsion copolymerization of styrene and acrylate monomers. It has good adhesion, transparent film, water resistance, oil resistance, heat resistance, and aging resistance. It can be used as an adhesive in combination with starch.

Acrylic latex includes pure acrylic resin and ethyl acrylate-styrene copolymer, which is beneficial to improve the hardness, tensile strength, water resistance, adhesion and scrub resistance of the spray layer.

The latex in the spray agent provided in the embodiment of the present application may be any one of acrylic latex, nitrile latex, carboxylated styrene-butadiene latex, and styrene-acrylic latex.

Furthermore, the applicant also found that the spraying agent for interlayer spraying may flow into the white water system of the paper machine along with the dehydration of the paper roll during the subsequent pressing process. Since part of the white water will be directly reused in the papermaking process, The spray agent transferred to the white water may affect the cleanliness of the whole white water system, and it is easy to cause bacterial growth when the production environment temperature is high. Therefore, the spray agent provided by the embodiment of the present application may optionally only consist of the above-mentioned starch liquid and a kind of latex, that is, only spray a kind of starch liquid and a kind of latex, so as to reduce the number of components of the spray agent as much as possible .

Optionally, the spraying amount of the starch solution is 30kg-35kg per ton of paper, such as 31kg/t, 32kg/t, 33kg/t, 34kg/t, etc. The spray amount of latex is 3.0kg-3.5kg per ton of paper, such as 3.1kg/t, 3.2kg/t, 3.3kg/t, 3.4kg/t, etc. Wherein, the spraying amount of the latex can be 8%-12% of the spraying amount of the starch liquid, such as 9%, 10%, 11% and so on.

It should be noted that the starch solution and the latex can be sprayed onto the molding paper separately, or they can be mixed into a solution and then sprayed onto the molding paper. Wherein, the proportioning of the spray liquid formed by mixing the starch liquid and the latex is determined according to the spray amount ratio of the above-mentioned latex and the starch liquid, that is, the ratio of the latex to the starch liquid is 8%-12%, and the prepared spray liquid The concentration can be 0.9%-1.2%, such as 0.93%, 0.97%, 1.03%, 1.08%, 1.15% and so on.

S14. Combination pressing.

After the spraying is completed, the sprayed multi-layer molded papers are stacked and pressed in multiple passes. Specifically, the sprayed multi-layer molding paper can be transferred to the surface of the drying cylinder, and the laminated multi-layer molding paper can be pressed and dehydrated by using the pressure roller and the drying cylinder. A press roll is used for the next press dehydration, and this is repeated many times to press the tightness of the paper to not less than 0.9g/m ³ .

Among them, the number of pressing can be adjusted according to the actual situation, for example, it can be pressed 3 times, 4 times, 5 times, 6 times, 7 times, etc. Similarly, the pressure can also be adjusted accordingly, and the specific pressing pressure can be controlled at 0.1MPa-1.0 Within the range of MPa, such as 0.2MPa, 0.4MPa, 0.6MPa, etc., as long as the paper is pressed to the preset tightness while achieving dehydration.

Optionally, in the combined pressing step, the pressure of the multi-pass pressing is gradually increasing. For example, in the 3-pass combined pressing, the pressures from the first pressing to the third pressing are 0.2MPa, 0.4MPa, 0.6MPa in turn .

It should be noted that the above-mentioned "gradually increasing trend" does not mean that the pressure of the multi-pass pressing in the combined pressing must gradually increase, but means that the pressure of the combined pressing is on the rise as a whole. For example, the number of combined pressing is 5, of which the pressing pressure of the 1st and 2nd lanes is 0.2MPa, the pressing pressure of the 3rd lane is 0.4MPa, and the pressing pressure of the 4th and 5th lanes is 0.6MPa. For another example, the number of combined pressing is 5, of which the pressing pressure of the 1st and 2nd lanes is 0.2MPa, the pressing pressure of the 3rd and 4th lanes is 0.4MPa, and the pressing pressure of the 5th lane is 0.6MPa. The specific pressing times and pressing pressure of combined pressing can be adjusted according to needs, which are not shown here one by one.

Certainly, the pressure of multiple pressings can also be set to increase sequentially, for example, the pressures of 5 pressings are 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa in sequence. Similarly, the specific pressing times and pressing pressure of combined pressing can be adjusted according to needs, which are not shown here one by one.

S15, drying.

Dry the combined pressed paper to obtain multi-layer laminated paper. Wherein, the grammage of each layer of forming paper of the multi-layer laminated paper is controlled within the range of 85g/m ² -95g/m ² through the above steps, such as 87g/m ² , 90g/m ² , 93g/m ² , and The overall thickness uniformity of the prepared multi-layer laminated paper tape is guaranteed. After drying, the multi-layer laminated paper can be subjected to surface treatment such as calendering, and then rolled.

It should be noted that the above-mentioned method for preparing multi-layer laminated paper only shows some key steps. The production process of multi-layer laminated paper can actually include some other steps. Please refer to FIG. 3 . FIG. 3 is a schematic flowchart of a method for preparing multi-layer laminated paper provided in some embodiments of the present application.

The preparation process of multi-layer laminated paper includes:

Take 10-30 parts of kraft bleached coniferous wood, and sequentially carry out the treatment of the four steps of loose pulp A1, deployment A2, slag removal A3 and beating A4; wherein the step of loose pulp A1 can be completed by the loose pulp equipment; After A1 is transferred to the pulping tower for blending A2, the pulping tower is a kind of normal-pressure container used for storing and blending pulp in the paper industry; then further use filtering equipment to remove slag A3, and then beat A4 to make pulp The specific process can be found above.

Take 70-90 parts of sulfate-bleached broad-leaved wood, and sequentially carry out four steps of pulping B1, blending B2, slag removal B3 and beating B4. The above-mentioned processing steps of the two pulps are basically the same, and the processing of the two pulps can be carried out synchronously.

After the two kinds of pulp are processed, the pulp is blended, specifically including pulping C1 and adding reagent C2, that is, the two pulps are mixed together in the pulping tank and mixed, and the corresponding reagents are added in the grid-connected pulping tank. For specific reagents, please refer to The above description about the slurry preparation will not be repeated here. Pulp storage C3 is carried out after the addition of reagents is completed, that is, the slurry is transferred to the pulp storage tank, so that the above two pulps and the added reagents are mixed evenly in the pulp storage tank. Then carry out pre-copying preparation C4, that is, transfer the uniformly mixed slurry to the surface/bottom forecourt, and prepare for papermaking. At this time, the slurry in the forecourt has been in a stable state, and the air in the slurry has been discharged. And the fiber ratio, concentration and other standards have met the requirements of copying.

Further carry out copying C5, that is, use the pulp pump to pump the pulp that meets the papermaking requirements to the paper machine, and perform screen C6, that is, use the screening device to perform fine screening, and the finely screened pulp enters the headbox of the paper machine , and then dehydrated and formed on the Internet to obtain a formed paper.

Further spray the molded paper with auxiliary agent C7, that is, spray the spray agent on the surface of the molded paper to be bonded, and then perform multi-layer lamination C8, stack the multi-layered molded paper after spraying, and stack The laminated multi-layer forming paper is pressed to a predetermined tightness through pressing C9 step, and then sequentially passed through drying C10 and rewinding C11 to obtain a multi-layer laminated paper.

The following are some examples of multi-layer laminated paper prepared by the method for preparing multi-layer laminated paper provided in this application.

Comparative example: After beating and pulping, spray starch liquid between the papers. According to the amount of sprayed starch liquid per ton of paper, the corresponding amount is sprayed on average between each layer, and then laminated, pressed, and dried to form paper. For details, please refer to the above, which will not be repeated here, and the following embodiments are the same.

Embodiment 1: After beating and pulping, spray starch liquid and acrylic latex between the papers, and then laminate, press, and dry to form paper.

Embodiment 2: After beating and pulping, spray starch liquid and nitrile latex between the papers, and then form paper after lamination, pressing and drying.

Example 3: After beating and pulping, spray starch liquid and carboxylated styrene-butadiene latex between the papers, and then laminate, press, and dry to form paper.

Embodiment 4: After beating and pulping, spray starch liquid and styrene-acrylic latex between the papers, and then laminate, press, and dry to form paper.

Wherein, the starch liquid consumption of embodiment 1-4 is equal to comparative example. Both Comparative Example and Examples 1-4 produced 3-layer and 10-layer multi-layer laminated paper, and cut them into corresponding specifications for testing. It can be understood that 3 layers and 10 layers are only the number of layers that are convenient for testing and selection, and cannot be used as a limit to the number of layers of laminated paper.

The first test method adopted in the embodiment of the present application is to use a paper cohesion tester to detect the cohesion of multi-layer laminated paper. Due to the limited range of the paper cohesion tester, the first test method is used to test 3-layer multi-layer laminated paper. For 10-layer multi-layer laminated paper, this application adopts the second test method for testing, specifically: take a certain length of paper tape, and wind it on a round roller with a diameter of 2-3cm for more than 5 turns in the forward and reverse directions, according to The delamination phenomenon of the paper tape evaluates its interlayer bonding strength.

Among them, the test paper is to cut the multi-layer laminated paper after rewinding into paper strips with a width of 25mm (3-layer paper sample) and 8mm wide (10-layer paper sample), and place it in a constant temperature and humidity room for 24 hours. test. The test results are as follows:

The above cohesion is measured after testing 3-layer paper samples with a paper cohesion tester, and the back and forth folding effect is measured after using the second test method above to test 10-layer paper samples. It can be seen that by spraying starch liquid and latex between the paper layers, the interlayer bond strength of the multilayer laminated paper can be greatly improved, and the paper flexibility of the multilayer laminated paper can be improved.

The present application further provides a multi-layer laminated paper, which is prepared by the above-mentioned preparation method of the multi-layer laminated paper.

Please refer to FIG. 4 . FIG. 4 is a schematic structural diagram of a multi-layer laminated paper provided by some embodiments of the present application.

The multi-layer laminated paper 10 provided by the embodiment of the present application has a multi-layer paper layer 100, and the multi-layer paper layer is sprayed with the above-mentioned spray liquid before lamination, and after lamination, it is pressed through multiple passes to make the multi-layer laminated paper 10 The tightness is not less than 0.9g/m ³ . Wherein, the grammage of each paper layer 100 is not less than 85 g/m ² and not more than 95 g/m ² , so that the multi-layer laminated paper 10 has good overall thickness uniformity.

It should be understood that the terminology used in the specification and appended claims herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. For example, the singular forms "a", "an", "a layer" and "the" are intended to include the plural forms unless the context clearly dictates otherwise. As another example, in the description of the present application, "multi-layer" means two or more layers, unless otherwise specifically defined.

It should be noted that multilayer laminated papers of other structures can also be produced through the above-mentioned preparation method of multilayer laminated paper, which are also within the scope of patent protection of the present application, and will not be listed here to avoid repeating them.

In the description of this application, reference to the terms "one embodiment," "some embodiments," "example," "specific examples," or "some examples" means that specific features described in connection with that embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

In summary, this application sprays starch liquid and latex on the surface of the multi-layer forming paper to be combined, then stacks the sprayed multi-layer forming paper and performs multi-channel combined pressing, and then combines the pressed The paper is dried to obtain a multi-layer laminated paper, which can improve the interlayer bonding strength and flexibility of the multi-layer laminated paper.

The above is only the implementation of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process conversion made by using the specification and drawings of the application, or directly or indirectly used in other related technologies fields, are all included in the scope of patent protection of this application in the same way.

Claims (12)

1. A preparation method for multilayer laminated paper, characterized in that, comprising: Perform beating and pulping to obtain the pulp required for papermaking; Sending the pulp to a plurality of paper nets of a paper machine, dehydrating and forming the pulp to obtain a multi-layer formed paper; Spraying a spraying agent on the surface to be bonded of multiple layers of the forming paper, the spraying agent includes starch liquid and latex, and the Tg value of the latex is not greater than 2 and not less than -2; Stacking the multi-layer molding paper after spraying and performing multi-channel combined pressing; drying the combined pressed paper to obtain the multi-layer laminated paper. 2. The preparation method of multilayer laminated paper according to claim 1, wherein the latex is any one of acrylic latex, nitrile latex, carboxylated styrene-butadiene latex, and styrene-acrylic latex. 3. The method for preparing multi-layer laminated paper according to claim 2, characterized in that the spraying amount of the latex is 3.0kg-3.5kg per ton of paper. 4. the preparation method of multi-layer laminated paper according to claim 1, is characterized in that, the preparation process of described starch liquid comprises: mixing raw starch with water to form a starch solution with a concentration of 1%-10%; The starch solution is gelatinized into the starch liquid at 90°C-100°C. 5. The method for preparing multi-layer laminated paper according to claim 4, characterized in that the amount of starch liquid sprayed is 30kg-35kg per ton of paper. 6 . The method for preparing multi-layer laminated paper according to claim 1 , characterized in that, in the step of performing multi-pass combined pressing, the tightness of the paper is pressed to not less than 0.9 g/m ³ . 7. The method for preparing multi-layer laminated paper according to claim 6, characterized in that, in the step of performing multi-pass combined pressing, the pressure of multi-pass pressed tends to increase gradually. 8. The method for preparing multi-layer laminated paper according to claim 1, characterized in that the grammage of each layer of the molded paper is controlled within the range of 85g/m ² -95g/m ² . 9. The preparation method of multi-layer laminated paper according to claim 1, characterized in that, the step of beating and pulping comprises: Use a conical refiner for the first stage of beating to separate the fibers in the pulp into filaments; A single disc mill beater is used for the second stage of beating, and a beating aid is added during the second stage of beating, so that the beating aid can fully contact the fibers. 10. The preparation method of multilayer laminated paper according to claim 9, characterized in that, the beating concentration of the first section of beating is 8%-12%, and the degree of beating is 20°SR-30°SR; The beating concentration of the second stage of beating is 3%-5%, the degree of beating is 38°SR-42°SR, and the addition amount of the beating aid is 10%-20% of the absolute dry mass of the fiber. 11. The preparation method of multi-layer laminated paper according to claim 9, characterized in that, the step of beating and pulping further comprises: after completing the second stage of beating, adding starch in pulp and wet strength The starch in the slurry is added in an amount of 6kg-15kg per ton of paper, and the wet strength agent is added in an amount of 1kg-2kg per ton of paper to dilute the slurry concentration to 1%-2%; Alkene ketene dimer is added in the amount of 20kg-35kg per ton of paper. 12. A multi-layer laminated paper, characterized in that the multi-layer laminated paper is produced by the method for preparing multi-layer laminated paper according to any one of claims 1-11.