KR20060080598A - Composition for dissociating wet strength paper - Google Patents

Abstract

The present invention relates to a wet strong paper dissociation composition capable of dissociating wet wet paper for kitchen tissues, sanitary ware and various wet strong papers that are used for industrial use. The composition for dissociating wet strong paper including sodium hypochlorite and saline vinegar To provide.

When dissociating wet strong paper using the composition of the present invention, while using less sodium hypochlorite than before, the dissociation effect can be increased to enable the recycling of the waste wet strong paper that is discarded as waste, thereby increasing the efficiency of resource utilization. have.

Wet strong paper, sodium hypochlorite, saline vinegar

Description

Composition for dissociating wet paper {COMPOSITION FOR DISSOCIATING WET STRENGTH PAPER}

The present invention relates to a wet strength paper dissociation composition capable of dissociating wet strength paper, such as wet tissue paper tissue, sanitary ware and industrial tissue.

Wet strength paper refers to a paper to which a wet strength enhancing resin is added. These wet strength enhancing resins include polyamide-epichlorohydrin (PAE), polyamine-epichlorohydrin (urea) and urea-formaldehyde. (UF; Urea-Form aldehyde) and melamine formaldehyde (MF) resins, and the like, and these wet strength enhancing resins are commonly added to paper, including paperboard, in the manufacture of paper.

Paper that is not wet-enhanced treatment maintains only 3 to 5% of the strength when wet with water, but wet strength paper can maintain more than 15% of the strength before being wet with water even when wet.

Generally, paper is produced by i) stock preparation, ii) papermaking, iii) processing, iv) cutting and packaging. Looking at this in detail.

i) stock preparation process

Raw material composition process consists of dissociation and beating process to process, mix and select all raw materials to be suitable for grassland. As raw materials, pulp, such as conifers, hardwoods, and other pulp, as well as recycled raw materials using milk packs and other recyclable waste paper, can be used.

In the dissociation process, a pulper, which is a rotating large mixer, mixes and dissociates the raw pulp with water under conditions suitable for paper production, thereby separating the raw material into individual fibers of porridge.

In the confession or refining process, the fuel mixed with water transported in the dissociation process is cut and fiberized to make a suitable raw material for making paper, and the raw materials and chemicals are mixed in a certain ratio to complete the paper raw material. At this time, the physical properties of the paper may change depending on the altitude.

ii) papermaking process

The papermaking process is a process of spreading and spraying pulp mixed with chemicals, and drying and processing the papermaking machine. The papermaking machine has the highest head box, wire part, press part, dryer part and size. It consists of a processing part and a calendar part. The head box located at the top of the paper machine dissipates over 97% of the water transferred in the raw material forming process and whites the appropriate amount, and spouts it onto the wire to distribute the paper evenly across the paper machine to make wetlands, dehydrate and complete The wetland is transferred to press parts and dewatered under pressure. In the dryer part, the wetland is dried using steam, and in size treatment, chemical treatment is applied to prevent water from penetrating into the paper surface to give hydrophobic function. The paper is then made through a calendar process that presses the paper through two or more metal rolls to smooth the paper surface. The paper produced in this paper is called base paper. The paper rewinder is then rolled up into rolls and transported to a process tailored to the final desired paper quality.

iii) processing

In the processing process, the coating process is processed to fill the smooth and smooth countless holes on the surface of the paper for printing. If you want gloss, the coated coated paper has high gloss and smoothness, and the thickness is adjusted. Will make a coated paper.

iv) cutting and packaging process

The wide coated paper, such as paper rewinder, is transferred to the desired process, roll products are commercialized, and sheet products are transferred to the cutting machine. After that, they are cut, packaged and commercialized to the desired standard.

As the commercial importance of regenerated cellulose-based paper products increases, the interest in developing a paper that can be easily repulped has increased, and thus, many recycled raw materials have been used as raw materials used in raw material composition during the papermaking process. In this case, when using waste paper that has not been subjected to wet paper strength treatment, the waste paper can be repulped by stirring and dissociating it with water. However, in the case of waste paper that has been enhanced with wet paper strength, such as kitchen tissue, sanitary and industrial packaging paper, the conventional paper pulp is used. Since it is not dissociated by the ignition method, it cannot be recycled and a large amount of waste wet paper has been incinerated.

Accordingly, various attempts have been made to improve the possibility of repulping of paper containing such a wet paper strength enhancing resin, which is generally made by modifying the repulping conditions. U.S. Patent No. 2,872,313 discloses an example of using hypochlorite as a method for repulping wet paper containing polyamide epichlorohydrin, and U.S. Patent No. 3,427,217, for example, sodium hypochlorite, ammonium persulfate, and the like. The use of the same oxide salts has been disclosed.

In addition, 'A study on the dissociation conditions and creping aptitude of hygienic paper milk pack paper' (Shin Dong-Soo, Korea Pulp Paper Society, 1995), sodium hypochlorite (NaClO) containing polyaminoamide epichlorohydrin It has been reported that the wet paper strength decreases as it decomposes PPE in paper cartons using wet paper and peels film on both sides, while additionally bleaching the paper, decreasing water resistance and increasing water absorption of cellulose. have.

However, polyamide epichlorohydrin is decomposed when only sodium hypochlorite is used for dissociation of wet strong paper, but sodium hypochlorite acts as a chlorinating agent, resulting in environmentally undesirable chlorine-containing decomposition products. There was a problem.

The present invention includes sodium hypochlorite and saline vinegar (hereinafter referred to herein as "saline vinegar") as a fermentation vinegar, commonly sold for edible vinegar, fruit vinegar and the like to solve the problems of the prior art. ) Is used together to provide a composition for dissociating waste wet papers without chlorine-containing degradation products.

It is also an object of the present invention to provide a method for dissociating waste wet paper by using the composition.

The composition for dissociating wet strong paper of the present invention is composed of hypochlorous acid (secondary hydrochloric acid) and saline vinegar.

Dissociation method of waste wet strength paper of the present invention comprises the first step of dipping waste wet strength paper in water; Hypochlorous acid and saline vinegar are added to dissociate the immersed waste wet paper.

Hereinafter, the components of the composition for wet strong paper dissociation of the present invention will be described in more detail.

Sodium hypochlorite (NaOCl) in the wet paper dissociation composition of the present invention is polyamide epichlorohydrin (PAE) through the oxidation and halogenation reaction of polyamide epichlorohydrin (PAE) in the resin component for wet strength enhancement And weakens the strong chemical bonds of cellulose. Thus, the wet paper ground with sodium hypochlorite reduces water resistance and allows water to be absorbed into cellulose. In the present invention, the concentration of sodium hypochlorite is preferably 10% to 12% (g / g), but when the concentration of sodium hypochlorite exceeds 12%, there is a problem that the acidity becomes stronger, If it is less than%, the rate of dissociation is slower than normal.

In the wet strong paper dissociation composition of the present invention, saline vinegar is a fermented vinegar, which is generally used for edible, and includes vinegar, fruit vinegar, and industrial vinegar does not exhibit the effect of the present invention. The saline vinegar is preferably used that contains 5 to 10% by weight of acetic acid when 10% by weight or more is stronger acidity, the rate of dissociation is slower than normal and less than 5% dissociation is rather poor.

The vinegar and sodium hypochlorite of the present invention is preferably used in a volume ratio of 0.8 to 1.2, when the volume ratio of vinegar and sodium hypochlorite exceeds 1.2, the acidity is stronger and dissociation rate is higher than normal. Slower, less than 0.8 dissociation is not good.

Hereinafter, the dissociation method of the wet strong paper will be described in more detail.

Dissociation method of the waste wet paper is a first step of immersing the waste wet paper in water; And a second step of dissociating the soaked waste wet paper by adding sodium hypochlorite and saline vinegar.

In the step of immersing the first wet paper in water, preferably, after the impeller of the pulper is operated, water is added thereto, and when water is supplied to the pulp by about one third or more, the waste wet paper together with the water. Input and immerse it. The amount of water suitable for immersing the waste wet paper in this step is 900 to 1100 parts by weight based on 100 parts by weight of wet strength support material. When the water is less than 900 parts by weight, there is a problem that the dissociation is not good because the density and viscosity are high, and when the water content exceeds 1100 parts by weight, there is a problem that the operating cost is increased by using excessive water.

In step 2, sodium hypochlorite and saline vinegar are added to the soaked wet paper to dissociate the waste paper. The dissociation composition of the present invention per 100 parts by weight of the raw waste wet paper is preferably 7.0 to 12.0 parts by weight. If it is less than 7 parts by weight, dissociation is difficult and time is delayed. This is because the speed is not fast anymore, only the cost is added.

According to the present invention, a reproducible quantitative experimental method for determining the dissociation degree and the repulping rate of wet paper, using the method described in the TAPPI method made by the Technical Association of Pulp and Paper Industry (TAPPI) It was.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. The following examples are presented to enable those skilled in the art to easily understand and reproduce the spirit of the present invention, and it will be apparent that the protection scope of the present invention is not limited thereto.

Test Example 1 Determination of Dissociation Conditions-Measurement of Paper Material Concentration

To evaluate the effect of feed concentration on the dissociation of wet paper, dissociate it with 2%, 3%, 4%, and 5% of sodium hypochlorite at 1800 ppm, respectively. The undissociated powder content and the degree of freedom were measured.

The actual dissociation of fibers in the pulper was carried out in the dissociation phase at the laboratory level. After adjusting the number of revolutions of the Pulper to 90,000 rev and starting the impeller, 10 tons of water was added and 1 ton of crushed kitchen wet tissue was immersed. Next, water is removed through the dehydrated wet strong paper, and the dissociation composition of the present invention is mixed with sodium hypochlorite (Kari Chemical Co., Ltd.) and saline brine vinegar prepared in Ottogi food at a volume ratio of 1: 1. Then, it was dissociated by the dissociation method of the present invention.

In order to measure the degree of dissociation of the wet paper, the undissociated fraction and the degree of free dissociation were measured. The dissociated fraction was measured on a Somerville screen having a slot size of 0.15 mm. After measuring the concentration of the prepared paper, put the dried fiber on the screen, pour tap water for 40 minutes, pass the dissociated paper through the screen, collect the undissociated fibers that did not pass through the screen, and measure the content of the added fiber. The undissociated fraction was shown by the ratio with the sheep. The measurement of Yeosu was measured in CSF mL units according to TAPPI Standard T 227 om-92 by distinguishing before and after screening using a Canadian freeness tester. The results are shown in <Table 1> and the lowest undissolved content was found when the stock concentration was 5%.

 <Table 1> Evaluation of Undissociated Flour Content and Yeosu Island According to Feedstock Concentration

Feedstock concentration (%) Undissolved fraction (%) Yeosu (ml CSF) 2 8.7 406 3 8.9 357 4 4.7 317 5 4.2 302

Test Example 2 Determination of Dissociation Conditions-Hypochlorite Concentration

To determine the degree of dissociation according to the concentration of hypochlorite, the same conditions as in Test Example 1 were performed except that the concentration of hypochlorite was 0, 500, 1000, 1500, and 3000 ppm, respectively, with the rotation speed of the pulp at 90000 rev. After dissociation, undissociated fraction and Yeosu-do were measured under the same conditions, and are shown in <Table 2>.

TABLE 2

Concentration of hypochlorite (ppm) Undissolved meal content (%) Yeosu (mL CSF) 0 50.5 416 500 52.5 347 1000 22.7 342 1500 3.1 297 2000 0.1 287

<Test Example 3> Evaluation of undissociated powder content and freeness according to the composition ratio of sodium hypochlorite and saline vinegar

The number of rotations of the pulp is 110000 rev, and the content of sodium hypochlorite and vinegar is changed as follows, and the undissociated powder content and the degree of freedom after dissociation in the same manner as in Test Example 1 are measured. Shown in

TABLE 3

Hypochlorite concentration (ppm) Vinegar Concentration (ppm) Undissolved fraction (%) Yeosu (mL CSF) 0 0 50.5 416 1800 0 1.3 282 900 900 23.6 360 0 1800 59.4 360

<Example> Evaluation of Tensile Index and Whiteness after Paper Making with Dissociated Paper

The number of revolutions of the Pulper was adjusted to 90000 rev, the impeller was turned on, 10 tons of water was added, and 1 ton of crushed kitchen wet tissue was immersed. Remove the water through the dehydrated wet force paper dehydrator, dissociate the wet strength paper while changing the content of the vinegar prepared in Ottogi foods with respect to 1800 ppm of sodium hypochlorite, and then measure the undissociated powder content and Yeosu It was. Thus, the paper was manufactured using the dissociated paper.

A square sheet paper machine was used to manufacture paper, and the basis weight of the paper, which is the weight of fibers existing in an area of 1m × 1m of paper, was 100 g / m 2. Tensile strength and whiteness of the paper thus prepared were measured. Tensile strength of the manufactured paper was measured using a tensile tester, and the tensile strength was measured by TAPPI Standard T404, and the measured tensile strength was divided by the basis weight of the paper. . The whiteness of the paper produced by TAPPI Standard T452 was measured using a whiteness meter. The results are shown in Table 4.

Comparative Example

Except for the case in which no saline vinegar was added, the dissociated wet strength paper was prepared in the same manner as in Example, and the undissolved powder content, freeness, tensile strength, and whiteness measured by preparing paper were shown in <Table 4>.

TABLE 4

Addition of saline vinegar (ppm) Undissolved meal content (%) Yeosu (mL CSF) Tensile Index (Nm / g) Whiteness (%) Comparative Example 0 4.96 302 43.55 79.37 Example 925 0.32 277 52.04 78.76 2000 0.11 277 57.12 78.73 3200 0.59 297 56.65 77.93 3700 0.21 297 56.85 78.01

As shown in Table 4 above, when sodium hypochlorite and saline vinegar are used together to dissociate wet strong paper, the content of undissociated powder is lowered to 1/15 or less compared with the case where no saline vinegar is added. It can be seen that there is an effect that greatly increases. The fact that the undissociated fraction content is less than 1% actually means that the wet paper is completely dissociated.

In addition, even when using the vinegar, when the paper was manufactured using the dissociated material, the tensile strength of the paper was increased, and there was no change in the whiteness.

  As described above, when using vinegar with sodium hypochlorite for dissociation of wet strong paper, the dissociation effect of recycled raw materials was greatly increased.

When using the composition for dissociating wet strong paper of the present invention by using less sodium hypochlorite than before, by reducing the chlorine-containing decomposition products can reduce the environmental pollution, there is no value in recycling waste wet paper was discarded as waste It is possible to increase the efficiency of resource utilization by enabling this.

Claims (4)

A composition for dissociating wet strong paper comprising sodium hypochlorite and saline vinegar. The method of claim 1, The sodium hypochlorite and saline vinegar is wet strong paper dissociation composition, characterized in that mixed in the range of 1: 0.8 ~ 1.2 in volume ratio. The method of claim 1, The saline vinegar is wet strong paper dissociation composition, characterized in that the acetic acid concentration of 5-10% by weight. The method of claim 1, The sodium hypochlorite aqueous solution is a wet strong paper dissociation composition, characterized in that the concentration is 10-12% by weight.