KR20230074966A - Manufacturing method of high-endurance paper and product using the same - Google Patents

Abstract

Disclosed is a method for manufacturing high-endurance paper comprising the following steps: (a) forming a paper stock containing latex; (b) manufacturing a base paper from the stock containing latex using a paper machine; and (c) drying the base paper. A manufacturing method is disclosed. According to the present invention, it is possible to manufacture paper products with improved durability even without a coating process.

Description

Method for manufacturing high-endurance paper and products using the same {MANUFACTURING METHOD OF HIGH-ENDURANCE PAPER AND PRODUCT USING THE SAME}

The present invention relates to a method for manufacturing high-durability paper and a product using the same, and more specifically, to a technique for improving the durability of paper in manufacturing paper and paper products using the same by adding latex in the paper stock process.

As the use of plastic disposable products increases, the problem of environmental pollution due to the discharge of plastic waste has become a serious problem. Plastic disposables are mostly made of general-purpose polymers such as PE (Polyethylene), PP (Polypropylene), PC (Polycarbonate), etc. These materials do not rot even when buried in the ground and generate high heat or harmful gases even when burned, so it is difficult to dispose of them. there is Therefore, attention is being focused on the development of materials that can replace plastics.

Recently, paper molded products using paper (pulp), which has a faster natural decomposition rate than plastic, have been proposed as a technology to replace plastic products. However, paper molded products are weak in mechanical properties such as durability compared to plastic products, so they are insufficient to replace plastics.

Although latex has been used in paper production due to its excellent adhesive strength and excellent fluidity in a high shear region, it is mainly proposed as a coating liquid composition for imparting special functions to paper. For example, Korean Patent Registration No. 0553199 discloses a technique for appropriately balancing various printing properties such as white paper gloss, printing gloss, water resistance and ink adhesion by including latex in a paper coating composition.

However, the above prior literature is not a technology using latex to improve the durability of paper, and in order to express the physical properties of latex, a step of coating with a coating liquid composition containing latex must be added to the surface of the prepared paper, and appropriate coating properties There is a problem in that a process for preparing an optimal coating liquid composition is additionally required to obtain.

Therefore, it is required to develop a technology capable of improving the durability of paper itself by using latex in a simpler way.

Korea Patent Registration No. 0553199 (2006.02.10)

The present invention is to solve the problems of the prior art as described above, and an object of the present invention is to provide a technique for producing highly durable paper by adding latex in the paper stock process.

In addition, another object is to provide a technology capable of obtaining uniform durability over the entire area of paper by imparting uniform dispersibility of latex after the paper making process including latex.

The object of the present invention is not limited to the above, and other objects and advantages of the present invention not mentioned can be understood by the following description.

High-strength paper manufacturing method according to an embodiment of the present invention for achieving the above object, (a) forming a pulp stock containing latex, (b) base paper from the stock containing latex using a paper machine It is characterized in that it comprises a papermaking step of producing and (c) the step of drying the base paper.

The step (a) includes (a-1) dissociating the pulp by introducing the pulp into water, (a-2) beating the pulp using a beating machine, (a-3) adding water to the stock concentration. It may include a dilution step to adjust.

In addition, the latex-containing stock may be prepared by adding latex to the stock in the dilution step (a-3).

In addition, after the papermaking step, a calendering process may be performed under predetermined temperature and pressure conditions in order to improve the dispersibility of the latex included in the paper. At this time, the predetermined temperature may be set to a glass transition temperature or higher of the latex.

In addition, the latex is natural latex or synthetic latex having a glass transition temperature of -30 to 50 ° C, and may be added in an amount of 0.1 to 50 wt% based on the weight of the pulp.

A paper product according to another aspect of the present invention is characterized in that it includes paper produced by any one of the above methods.

The paper may have a bending resistance of 1000 times or more measured according to KS M ISO 5626 (paper-bending strength test).

According to an embodiment of the present invention, there is an effect of producing highly durable paper by adding latex in the paper stock process.

In addition, according to an embodiment of the present invention, there is an effect of imparting uniform dispersibility of latex by performing a calendering process at a temperature equal to or higher than the glass transition temperature of latex and at a constant pressure after the paper making process.

However, the effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

1 is a flowchart of a method for manufacturing high durability paper according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail, but the present invention is not limited or limited by the embodiments. In describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms used in this specification should be interpreted as generally understood by those skilled in the art unless otherwise defined.

1 is a flowchart of a method for manufacturing high durability paper according to an embodiment of the present invention. Referring to FIG. 1, the method for manufacturing high-durability paper according to an embodiment of the present invention includes a pulp dissociation step (S10), a pulp beating step (S20), a dilution step (S30), a papermaking step (S40), and a drying step (S50). can include

The pulp dissociation step (S10) is a step of dissociating the pulp by putting it into water to be 0.1 to 10 wt%, wherein the pulp may be cotton pulp or wood pulp.

In the pulp dissociation step (S10), additives such as polymer powder or fibers may be added to increase the strength of the paper. The additives added are biodegradable polymers such as PLA (Poly Lactic Acid), resins with a melting point of 30 to 300 ° C, polyethylene (PE), polypropylene (PP), polystyrene (PS), polycarbonate It may be a general-purpose polymer such as (Polycarbonate; PC) or polyethylene terephthalate (PET). The polymer powder or fibers added to the pulp may have a diameter of 1 to 1,000 μm and a length of 0.1 to 20 mm.

Polymer powder or fiber may be added by 0.1 to 50 wt% based on the weight of the pulp.

After the pulp dissociation step (S10), a pulp beating step (S20) is performed to form stock for papermaking. Beating can be carried out using a beating machine such as a Valley Beater, and the beating can also be carried out in the range of 45 to 60°SR. When additives such as polymer powder or fibers are mixed with the pulp before the pulp beating step (S20), the strength of the paper can be increased by sufficiently bonding the fibers constituting the pulp with the polymer material during the beating process.

After the pulp beating step (S20) is completed, a dilution step (S30) is performed to adjust the stock concentration by adding water so that the papermaking step can proceed smoothly. Through the dilution step (S30), the pulp concentration in the stock may be adjusted to be in the range of 0.1 to 1 wt%.

In the dilution step (S30), latex is added to the stock. The latex may be natural latex or synthetic latex. Natural latex may include protein, starch, sugar, natural rubber, and the like, and synthetic latex may include Nitrile Butadiene Rubber (NBR) and Styrene Butadiene Rubber (SBR). The glass transition temperature of the latex added to the stock may be -30 to 50 ° C, and may be added by 0.1 to 50 wt% based on the weight of the pulp.

Since latex is a material with excellent elastic modulus and resilience, durability of paper itself can be improved without additional processes such as coating by adding latex. In addition, since latex is basically in a water-dispersed state, it is easy to put into the paper stock during the paper manufacturing process.

On the other hand, in this embodiment, it is described that the latex is added in the dilution step (S30), but is not limited thereto. The latex may be added prior to the dilution step (S30), such as in the dissociation step (S10) or the beating step (S20). However, since dilution of the stock is to reduce the weight variation by making the pulp as evenly distributed as possible in the paper manufacturing process, it is preferable to add latex in the dilution step (S30) in which the pulp is dispersed as evenly as possible.

Paper is prepared by performing a papermaking step (S40) of preparing base paper from the diluted stock to which latex is added using a papermaking machine such as a long netting paper machine or a round netting papermaking machine, and proceeding to a drying step (S50). The drying step (S50) may proceed for 2 to 500 seconds at a temperature of 75 to 350 °C.

Optionally, a surface treatment step of impregnating the paper into a surface treatment solution may be performed to further increase the strength of the dried paper. As the surface treatment solution for the first impregnation treatment, polyvinyl alcohol (PVA), which is a water-soluble polymer miscible with pulp, or a starch solution may be used. The concentration of the surface treatment liquid may be 0.1 to 6 wt%, and other additives may be further included in the surface treatment liquid.

The primary impregnated paper may be subjected to secondary impregnation in the curing liquid. Borax or boric acid may be used as a curing agent included in the curing liquid. The concentration of the curing liquid may be 0.1 to 5 wt%.

The step of first impregnating the surface treatment solution may be replaced with a step of surface treatment using a top-size method instead of an impregnation method. For example, while maintaining the surface treatment liquid at a temperature of 50 ~ 75 °C, the previously manufactured paper undergoes a top size process using a rod or size press, and then passes through a compression press to remove excess surface treatment liquid. can be used At this time, a polyaminoamide epichlorohydrin (PAE)-based resin, urea, and a trihydric alcohol-based compound may be added to the surface treatment solution. By using a surface additive solution having such a composition, it is possible to improve properties such as high bending resistance of paper having appropriate flow properties and being suitable for the top-size method.

In addition, when the surface treatment step is performed, the drying step (S50) may proceed after the surface treatment step.

Optionally, the paper manufacturing method according to an embodiment of the present invention may include adding other additives such as a sizing agent or a wet strength enhancer. Other additives may be added in at least one of the pulp dissociation step (S10), the beating step (S20), the dilution step (30), the papermaking step (S40), and the surface treatment step, or may be added through a separate step. By adding a sizing agent or a wet strength reinforcing agent, the strength of the paper molded product for use in a wet state can be further improved.

In addition, a high-temperature calendering process may be performed after the papermaking step (S40) to improve the dispersibility of the latex included in the paper. The calendering process is to apply pressure evenly according to the temperature in order to improve the smoothness of the paper. can The calendering temperature can be set between 20℃ and 200℃ depending on the glass transition temperature and melting point of the added latex, and the pressure can be set between 0 and 80bar depending on the thickness of the paper. Depending on the desired smoothness and air permeability, the speed of the calendering rolls can be set to 1 to 5 m/min.

According to the paper manufacturing method according to the embodiment of the present invention described above, the durability of the paper can be greatly improved by manufacturing the paper by adding latex to the paper stock in which the pulp is dissociated. In addition, the dispersibility of the latex may be improved by performing the calendering process under a high temperature condition equal to or higher than the glass transition temperature of the added latex.

Paper manufactured according to an embodiment of the present invention is suitable for use as a material for disposable products instead of plastic because durability is greatly improved compared to general paper due to the addition of latex. In addition, through the surface treatment step of sequentially impregnating the paper produced through the papermaking step into the surface treatment liquid and the curing liquid, the durability of the paper molded product can be further improved.

Based on specific comparative examples and examples, the present invention will be described in more detail below.

<Example 1>

The linter cotton pulp was dissociated by adding water to a stock concentration of 1.5 wt%. Then, it was beaten to 45 ° SR using a Valley Beater with a capacity of 23 L, and diluted by adding water so that the stock concentration was 0.3 wt%. After that, synthetic latex SBR (Styrene Butadiene Rubber) (glass transition temperature: 12 ℃, average particle diameter: 1.3㎛) was added at 5 wt% compared to pulp content, and then mixed, and then using a circular handing machine to obtain a basis weight of 200 g / m ² Paper was prepared. After drying at 105 ° C. for 4 minutes, it was left at 23 ° C. and 50% constant temperature and humidity conditions for more than 24 hours.

<Example 2>

Base paper was prepared in the same manner as in Example 1, except that the latex to be added was changed to SBR (Styrene Butadiene Rubber) (glass transition temperature: -1 ° C, average particle diameter: 1.45 μm).

<Comparative example>

Base paper was prepared in the same manner as in Example 1, except that latex was not added.

<Theft resistance and air permeability measurement results>

Cut resistance and air permeability were measured for the samples of Examples and Comparative Examples.

The break resistance was performed in accordance with KS M ISO 5626 (paper-resistance test), and the air permeability was performed in accordance with KS M ISO 5636-3 (paper and cardboard-permeability measurement-Part 3: Bentson method).

Table 1 shows the cut resistance and air permeability measurement results of Examples and Comparative Examples.

From the results of Table 1, it can be seen that in the case of the examples in which latex was added to the pulp furnish, the cutting resistance was greatly improved compared to the comparative example in which latex was not added.

Although described above with reference to the limited embodiments and drawings, this is exemplary, and it will be apparent to those skilled in the art that various modifications and implementations are possible within the scope of the technical spirit of the present invention. In addition, the technical ideas described in each embodiment may be implemented independently or in combination with each other. Therefore, the protection scope of the present invention should be defined by the description of the claims and their equivalents.

Claims (8)

As a method for producing high durability paper,
(a) forming a latex-containing pulp furnish;
(b) a papermaking step of preparing base paper from the latex-containing stock using a papermaking machine; and
(c) drying the base paper;
High durability paper manufacturing method comprising a. According to claim 1,
In step (a),
(a-1) dissociating the pulp by introducing the pulp into water;
(a-2) beating the pulp using a beating machine;
(a-3) a dilution step of adjusting stock concentration by adding water;
High durability paper manufacturing method comprising a. According to claim 2,
The stock containing the latex is prepared by adding latex to the stock in step (a-3). According to claim 1,
After the papermaking step, a high-durability paper manufacturing method in which a calendering process is performed under predetermined temperature and pressure conditions to improve the dispersibility of latex contained in the paper. According to claim 4,
The predetermined temperature is set to a glass transition temperature or higher of the latex. According to claim 1,
The latex is natural latex or synthetic latex having a glass transition temperature of -30 to 50 ° C, and is added in an amount of 0.1 to 50 wt% based on the weight of the pulp. A paper product comprising paper produced by the method according to any one of claims 1 to 6. According to claim 7,
The paper is a paper product having a break resistance of 1000 or more times measured in accordance with KS M ISO 5626 (paper-bending strength test).

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