JPH1060486A - Backing roll cleaning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for cleaning a backing roll capable of preventing the backing roll from soiling without giving any ill effect to the quality of a coated paper and improving a cleaning efficiency by using a cleaning water containing a composition consisting of a polyethylene oxide and a polyamine. SOLUTION: This method for cleaning a backing roll in cleaning the backing roll by injecting a cleaning water to a doctor part for cleaning the backing roll in a one side coating machine, is to use the cleaning water containing 1-5000ppm weight ratio of a composition, consisting of (A) polyethylene oxide and (B) a polyamine in a ratio of the components of 0-100wt.% component (B) based on 100wt.% component (A). Further, as the component (A), e.g. a compound prepared by a coordinated ring opening polymerization of ethylene oxide and having approximately 100000-5000000 molecular weight, is preferably used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a backing roll of a single-side coating machine, and more particularly to a method for forming a coating and a coating layer on a backing roll without adversely affecting the quality of a coated paper surface. The present invention relates to a cleaning method using cleaning water having an action of preventing adhesion of a tacky component containing a component as a main component to a backing roll and improving cleanability.

[0002]

2. Description of the Related Art When coating with a single-side coating machine equipped with a backing roll, first, one side of the base paper is coated with a coating material, and then a metaling device such as a blade is used to obtain a specified coating amount. To scrape off excess paint and pass through the drying process. Next, the opposite side of the base paper is similarly coated and dried to obtain a double-side coated paper.

[0003] In the case of this double-side coated paper, a coating method in which the paint is applied narrower than the paper width of the base paper and both ends of the ears are left uncoated, or a method in which the coating is applied wider than the base paper, that is, a part of the coating is directly applied to the backing roll. In this method, extra paint applied to the base paper is scraped off. Since the paint applied on the backing roll with a width equal to or larger than the width of the base paper is not completely scraped off by the metering device, it is washed by the washing water of the backing roll with a floclin doctor and discarded as waste water.

Further, the paint on the backing roll adhered through a defective portion of the base paper such as a pinhole is also washed by the washing water of the backing roll.

Further, at the time of coating the opposite surface, the paper surface in contact with the backing roll has already been coated. If the composition and properties of this coating layer and drying are insufficient, the paper surface adheres to the backing roll. In addition, since the surface of the backing roll is soiled due to partial peeling from the coating layer, a floclin doctor is installed on the surface of the backing roll, and the backing roll is cleaned and peeled off.

The cleaning water alone is not completely removed by the floclin doctor but adheres to the backing roll surface, and the water transfers when it comes into contact with the coating layer. It is estimated that the amount of the transfer washing water is at most about 2 g / m ² .

However, even if such a cleaning method is carried out, if the operation is continuously performed for a long time, dirt accumulates on the backing roll. The cleaning water adhering to the surface becomes uneven, which results in uneven drying of the coated paper and damage to the coated paper surface.

Further, in recent years, the coating speed has been increased to improve the productivity, and the gel content of the polymer has been conventionally increased depending on the application in order to improve the performance of the synthetic rubber latex which is the binder component of the coating layer. In addition, the backing roll is more easily soiled due to a lower glass transition temperature and the like.

Stopping the coating machine for removing backing rolls and floc-lind doctors is a serious problem in the production of coated paper, and it is strongly desired to prevent the backing rolls and the like from becoming dirty.

As a method of solving this problem, SBR and M which are usually used as one of the binder components in the coating material are used.
The quality of the synthetic rubber latex such as BR or MSBR is designed to reduce the backing roll dirt by sacrificing some of the physical properties of the coated paper. That is, an increase in the styrene or methyl methacrylate component, which is a hard component in the synthetic rubber latex, an increase in the crosslink density, an increase in the hard component in the shell layer in the core-shell latex particle formation, an increase in the crosslink density, etc. A method of reducing the adhesiveness of latex and the like, a method of improving the mechanical stability of a paint containing a synthetic rubber latex, and the like have been adopted.

[0011] Coated paper obtained using such a latex may deteriorate the suitability for web offset printing, but must also simultaneously prevent contamination of the backing rolls and the like. At present, the deterioration of printability is minimized as much as possible.

As a method of improving the cleaning effect of the backing roll, a method of using cleaning water containing a chemical agent such as a surfactant may be considered, but it is not preferable because it has a bad influence on the quality of the coated paper surface. That is, when the surfactant is present on the coated paper surface, the paper surface wear strength when wet and the wet topic strength during offset printing are reduced, and the quality of the coated paper is reduced. From such a viewpoint, the development of technology for reducing the amount of a surfactant, ie, an emulsifier, used in the production of a synthetic rubber latex, which is one of the binders, is an important issue.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide a new backing roll cleaning method which solves the above-mentioned problems in the prior art.

[0014]

SUMMARY OF THE INVENTION In view of the above situation, the present inventors have made it clear that the improvement of the cleaning effect of the backing roll requires a high quality of latex in which the quality of the coated paper surface is further taken into consideration in the quality design. From the viewpoint that the quality of coated paper can be designed, cleaning water with high cleaning efficiency for the backing roll has been found, and the present invention has been completed. The above object is achieved by the following means.

That is, the present invention relates to a method for washing a backing roll by pouring washing water into a doctor for washing a backing roll of a single-side coating machine, comprising a composition comprising polyethylene oxide and a polyamine. The present invention proposes a backing roll cleaning method, characterized by using a cleaning water containing 1 to 5,000 PPM by weight of the composition having a composition ratio of 0 to 100% by weight of polyamine with respect to 100% by weight of polyethylene oxide. It is.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

The inventors of the present invention have studied diligently the backing roll washing water which prevents the latex component from adhering to the backing roll without adversely affecting the quality of the coated paper surface, or which has excellent washing properties. It has been found that certain water-soluble polymers are suitable for the purpose. That is, the present invention is a composition comprising polyethylene oxide (hereinafter referred to as PEO) and polyamine as a backing roll washing water, wherein the composition ratio is 0 to 100% by weight of polyamine to 100% by weight of polyethylene oxide. Certain of the compositions are 1 ppm to 5000 ppm by weight.
It is characterized by using cleaning water containing PPM.

The PEO used in the present invention is usually produced by coordination ring-opening polymerization of ethylene oxide, and those having a molecular weight of about 100,000 to 5,000,000 are commercially available. These may be of any molecular weight for the purposes of the present invention.

In the present invention, the concentration of the above compound in the washing water is 1 PPM to 5000 PPM, preferably 5 PPM to 2500 PPM. More preferably, it is 20 PPM to 1000 PPM. The concentration is 1P
If it is less than PM, the effect of preventing adhesion of latex components and the cleaning effect are insufficient, and if it exceeds 5,000 PPM, the glossiness of the coated paper in contact with the backing roll tends to decrease.

In the present invention, in the composition comprising PEO, the composition ratio of the polyamine is 0 to 100% by weight based on 100% by weight of PEO. This is 10
If it exceeds 0% by weight, the adhesion of the latex rubber component is deteriorated and the washing effect is reduced, which is not preferable. The polyamine used in the present invention is a cationic polymer containing a quaternary ammonium salt obtained by reacting epichlorohydrin with various amines as epihalohydrin.
It is. The process for producing polyamines is already described in US Pat.
No. 8945 and Canadian Patent No. 1,096,070.

The polyamine produced by the above-mentioned known production method can be used as the polyamine of the present invention.
Preferred are polyamines obtained by reacting one or more amines such as dimethylamine, ethylenediamine, tetraethylethylenediamine, and triethanolamine with epichlorohydrin. Usually, epichlorohydrin is added under stirring in the presence of water to make a suspension, and then dimethylamine is added and reacted. In this case, the raw material addition temperature is 20 to 35
The reaction after addition is carried out at 40 to 100 ° C., the proportion of water in the reaction system is 10 to 55%, and the molar ratio between amines and epichlorohydrin is approximately equimolar. The polymerization reaction, ie, the thickening reaction, is advanced until the concentration of the cationic polymer portion excluding the counter anionic atom or atomic group of the polyamine becomes about 10 to 250 cps in terms of 37%. After completion of the thickening reaction, water is added to adjust the concentration, or simultaneously with the concentration adjustment, an acid such as hydrochloric acid or sulfuric acid is added to adjust the pH to obtain a polyamine.

The reaction rate increases as the proportion of water in the reaction system decreases and as the reaction temperature increases, but when the reaction rate is increased during the course of the reaction, ethylenediamine and sodium carbonate are used.
A method of adding potassium carbonate, potassium carbonate, caustic soda or caustic potassium, or further adding epichlorohydrin is also carried out.

In the present invention, the polyamine obtained by the above-mentioned production method using the preferable raw materials as described above has a cationic charge density of the cationic polymer portion excluding the counter anion atom or atomic group of 90 to 120 meq.
/ G and a molecular weight of about 20,000 to 300,000. The above-mentioned polyamines are commercially available, and any of them can be used in the present invention.

The cleaning method of the present invention is a method of cleaning using a cleaning water to which PEO or a PEO composition as an essential component of the present invention is added, and is not particularly limited. That is, the washing water is poured into a doctor portion for cleaning the backing roll of the single-side coating machine, and the backing roll is washed together with the floclin doctor installed on the surface of the backing roll.

[0025]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In addition,%, parts, and PPM indicate the weight ratio unless otherwise specified. Example 1 70 parts of kaolin (trade name: manufactured by UW-90 / EMC) and 30 parts of finely divided heavy calcium carbonate (trade name: FMT90 / manufactured by Fimatec) were blended, and polyacrylic acid soda was used as a dispersant. 0.2 part was added and dispersed using a coil disperser to prepare a pigment slurry having a solid content of 68%. 6 parts of phosphoric acid-modified starch was added to the slurry thus obtained,
30 parts of SMBR latex for coated paper was added to prepare a coating liquid having a solid content concentration of 61.7%. This coating liquid is applied to the coating base paper using an automatic coating machine, and then dried for 30 seconds with a hot air dryer at 120 ° C. to obtain a coating amount of 17 g / m ^2.
Was obtained.

PEO having a molecular weight of 120,000 (trade name: Alcox R-150, manufactured by Meisei Chemical Industry Co., Ltd.) was dissolved in ion-exchanged water to obtain an aqueous solution having a concentration of 1000 PPM. Similarly, a 500 ppm aqueous solution of PEO having a molecular weight of 700,000 (trade name: Alcox E-45) and a 200 PPM PEO having a molecular weight of 4.5 million (trade name: Alcox E-240)
An aqueous solution of M was obtained as wash water.

Next, a method for evaluating the adhesion, the peeling property and the cleaning property between the backing roll and the coated paper surface will be described. (Hereinafter referred to as an evaluation test.) The same material as the backing roll, 100 mm long x 45 mm wide
Rectangular 90mm hardness NBR rubber plate, 270mm long
× Two rectangular iron plates weighing 9400 g and measuring 220 mm in width are adjusted in a constant temperature room at 50 ° C.

Next, one of the temperature-regulated iron plates is placed vertically 150
The three coated papers obtained above having a rectangular shape of 50 mm × width 50 mm are arranged at equal intervals with the coated surface on top. A PEO concentration of 1000 PPM adjusted to 50 ° C. and 500
Wash water of PPM and 200 PPM was applied to each coated surface with a flat bar. Immediately after the application, an NBR rubber plate was superimposed on the application surface, and an iron plate was further placed thereon and fixed. Then, after pressing with a pressure of 5 kg for 30 seconds using a press machine (manufactured by Kumagai Riki Kogyo Co., Ltd./press machine for square sheet machine),
Decompress and forcibly remove the coated paper from the NBR rubber plate.
The state of attachment on the R rubber plate was observed.

0 point when adhered to the entire surface of the NBR rubber plate,
When there was no adhesion at all, it was given 5 points, and a five-step evaluation was performed to judge the superiority or inferiority.

Further, the difficulty of peeling off the adhered matter from the NBR rubber plate in water was observed as the difficulty of cleaning (◎ easily falling in water, Δ hard to fall, × not falling in water).

As a result, the PEO content was 200 PM, 5
When 00 PPM and 1000 PPM of wash water were applied to the coated paper, they were all easily removed from the NBR rubber plate. PE
When the O content was 200 PPM, the coating layer slightly adhered to the NBR rubber plate, but could be easily washed in water.

Table 1 summarizes the results of these evaluation tests. Example 2 In this example, the type of polyamine used, the combined ratio of PEO and the concentration of washing water, and the like will be described.

The following polyamines were obtained by known production methods. Epichlorohydrin 1.0 mol, dimethylamine 0.9 mol, ethylenediamine 0.045 mol ratio, molecular weight 40,000, cation charge density 9.9 meq / g
A 25% aqueous solution of polyamine was obtained. (Hereinafter referred to as polyamine-1.) Next, a molecular weight of 250,000 consisting of 1.0 mol of epichlorohydrin, 0.97 mol of dimethylamine and 0.16 mol of ethylenediamine, and a cation charge density of 11.8 m.
A 25% aqueous solution of eq / g polyamine was obtained. (Hereinafter referred to as polyamine-2) and epichlorohydrin.
0 mol, dimethylamine 0.97 mol, triethanolamine 0.01 mol and tetramethylenediamine 0.1 mol
Molecular weight of 270,000 and 10.5 meq / g in molar ratio
(Hereinafter, referred to as polyamine-3).

An example of the combination of these three polyamines with the 700,000 molecular weight PEO used in Example 1 will be described. The procedure of the evaluation test was exactly the same as in Example 1. Table 1 shows the evaluation results such as the combination ratio of polyamine and PEO and the total concentration thereof. Comparative Example 1 The combination ratio of PEO and polyamine is outside the scope of the claims of the present invention. The evaluation was performed in exactly the same manner as the evaluation test method of Example 1 except that the PEO having a molecular weight of 700,000 described in Example 1 was used in combination with the polyamine-2 described in Example 2 and an aqueous solution of polyamine-2 alone was used. Was. Also, the PEO of the present invention
A similar test was conducted using only ion-exchanged water containing no polyamine. (Comparative Example 1, Experiment No. 6) Table 1 shows the blending ratio of polyamine and PEO, the total concentration thereof, and the evaluation results. Example 3 An application example in which a high-concentration aqueous solution of PEO alone or in combination of PEO and polyamine is used as washing water will be described. In the evaluation test method described in Example 1, an evaluation test was performed in exactly the same manner as in Example 1 except that an aqueous solution containing both 2500 PPM, 3000 PPM and 4500 PPM of PEO or polyamine was used, and the press pressure was changed to 7 kg. did. Table 2 shows the blending ratio of polyamine and PEO, the total concentration thereof, and the evaluation results. Comparative Example 2 A comparative example in which the concentration of the washing water is outside the scope of the present invention, by using PEO alone or in combination with polyamine.

In Example 1, P having a molecular weight of 120,000 was used.
EO content of 5500PPM wash water and molecular weight 70
Evaluation was performed in exactly the same manner as the evaluation test method described in Example 1, except that the mixing ratio of the 10,000 PEO to the polyamine-3 described in Example 2 was 70:30 and the total concentration was 5,500 PPM. Was done. The results are shown in Table-2. Example 4 An example of an evaluation test using PEO alone or in combination with a polyamine and using a low-concentration aqueous solution of these as washing water is shown. PEO having a molecular weight of 700,000 in Example 1
Evaluation was performed in exactly the same manner as above, except that a low-concentration aqueous solution alone or in combination with the polyamine-3 described in Example 2 was used, and the press pressure was changed to 3 kg. PE
Table 3 shows the mixing ratio of O and polyamine, the total concentration thereof, and the evaluation results thereof. Comparative Example 3 The concentration of the washing water, which is an aqueous solution of PEO alone or in combination with polyamine, is outside the scope of the claims of the present invention.
The PEO having a molecular weight of 4.5 million used in Example 1 had a pH value of 0.1%.
Evaluation was carried out in exactly the same manner as in Example 4 except that 5 PPM washing water and a mixing ratio of PEO to polyamine-3 of 70/30 and a total concentration of 0.5 PPM were used. The results are shown in Table-3. Example 5 In this example, the effect on the physical properties of the paper such as the suitability for offset printing when the washing water containing the polymer used in the floclin doctor was transferred to the coated paper via the backing roll was examined.

70 parts of kaolin (trade name: UW-90 / manufactured by EMC), micronized heavy calcium carbonate (trade name: FM)
T-90 / Pharmatech Co., Ltd.) 30 parts were added, and 0.2 parts of polyacrylic acid soda was added as a dispersing agent.
A pigment slurry having a solid content of 68% was prepared by dispersing using a dispersing machine. To the slurry thus obtained, 6 parts of phosphoric acid-modified starch and 12 parts of SMBR latex were added to prepare a coating solution having a solid content concentration of 61.7%. This paint was applied to a high-quality paper having a basis weight of 104.7 g / m ² using an automatic coater, dried at 120 ° C. for 20 seconds, conditioned, and then roll temperature was set to 50.
The paper was passed twice through a super calender at 80 ° C. and a linear pressure of 80 kg / cm to obtain a coated paper for a printing test.

Next, the P of molecular weight 700,000 described in Example 1 was used.
Wash water containing 1000 PPM of EO is applied to the above-mentioned coated paper for printing test at 2 g / m ² using a flat bar, and dried and calendered according to the conditions and procedures for obtaining the coated paper for printing. A final test coated paper was obtained. In the same manner and in the same manner, the type of PEO, the type of polyamine,
Was applied as described in Table 4 to obtain the final coated paper for each test.

Next, regarding the final coated paper obtained as described in Table 4, the coating amount, blank gloss, print gloss, RI dry strength, RI wet strength, wet insertion, sucking swimsuit, ink set, Tests for trapping, air permeability, and smoothness were performed. There was no difference in quality other than gloss. The gloss measurement method is a gloss meter (GM-3D) manufactured by Murakami Color Co., Ltd.
Was used to measure the coated paper surface gloss at 75 °. The measurement results are shown in Table-5. Comparative Example 4 In the case where PEO is used alone or in combination with polyamine, the concentration of washing water as an aqueous solution is outside the scope of the present invention.
In Example 5, 5500P of PEO having a molecular weight of 120,000 was used.
PM wash water and molecular weight 700,000 PEO vs. polyamine-
3/70/30 solid content ratio and total concentration of 5500P
The evaluation was performed in exactly the same manner as in Example 5 except that PM washing water was used.

Further, the evaluation was carried out in exactly the same manner as in Example 5 except for using only the ion-exchanged water without using any PEO or polyamine.

The results are shown in Tables 4 and 5.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

[0045]

[Table 5] Table 1 shows Examples 1 and 2 and Comparative Example 1 which were pressed by a moderate press pressure. However, when the polyamine compounding ratio was out of the range of the present invention, even if the releasability was somewhat good, the cleaning properties tended to be inferior. . This is presumed to be due to the peculiar function of releasing, although PEO is hydrophilic.

Table 2 shows Examples 3 and Comparative Example 2 in which the concentration of the polymer contained in the washing water was high, that is, the peeling effect and the cleaning effect were high. Further promoted to find differences. With such a high concentration of washing water, the washing property was good even when the peelability was somewhat low. The problem with the use of high-concentration washing water is that the glossiness of blank paper, which is a term of offset printing suitability of coated paper to which the washing water has been transferred, is low, is that the coating water of Comparative Example 4 in Table 5 is used. This is apparent from a comparison between Coating-1 and Coating-3 coated with only ion-exchanged water.

Table 3 shows an example of pressure bonding at a low press pressure, which is an example corresponding to a case where the backing roll has relatively little dirt. Therefore, this is an example in which the polymer content in the washing water is small. It is clear that the polymer content needs to be within the scope of the present invention.

The coating layer of the coated paper used in the pressing, peeling and washing tests with the same NBR rubber plate as the backing roll has a higher latex content than the coating layer of the ordinary coated paper. Therefore, although it is an evaluation test under conditions where it is easy to apply pressure, it is difficult to peel off, and it is also difficult to wash, when the polymer of the present invention is applied, the release property is excellent, and even if there is some attached matter. If it was immersed in water, it could be easily washed.

[0049]

According to the method of the present invention, the backing roll can be prevented from being stained and the washing efficiency can be increased without adversely affecting the quality of the coated paper. Furthermore, continuous long-time operation becomes possible, and productivity can be greatly improved.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Kojima 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemicals Co., Ltd.

Claims (1)

[Claims] 1. A method for washing a backing roll by pouring washing water into a doctor for washing a backing roll of a single-side coating machine, comprising a composition comprising polyethylene oxide and polyamine, wherein the composition ratio is polyethylene. 0-100 polyamine per 100% by weight of oxide
% By weight of the composition is 1 ppm to 500 ppm by weight.
A backing roll cleaning method, comprising using cleaning water containing 0 PPM.