JPS62282094A - Poster paper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to poster paper that can withstand use even under harsh environmental conditions and has excellent printing reproducibility.

[Conventional technology]

Traditionally, poster paper was made of high-quality paper or coated paper.

Synthetic paper is used. However, poster paper made of high-quality paper or coated paper generally has a high elongation when immersed in water, and as a result of water absorption due to changes in humidity or rainfall, the poster swells, wrinkles, or becomes uneven on the surface, which deteriorates the appearance of the poster. This results in significant damage and shortens the service life.

As a countermeasure to this problem, it has been proposed to process the poster surface with polypropylene resin, etc., but this increases the cost and the prevention effect is insufficient due to water absorption from the back side, so it cannot be a complete improvement. On the other hand, poster paper made of synthetic paper does not itself have water absorbency, so it does not deform due to water absorption like high-quality paper or coated paper made of natural fibers, but on the other hand, because it does not have water absorption, the printing method is special. , and the print finish is also inferior to that of cast coated paper. Furthermore, it has the disadvantage of being more expensive than ordinary paper.

[Problem that the invention attempts to solve]

As mentioned above, the quality of high-quality paper and coated paper conventionally used as poster paper deteriorates due to the external environment such as humidity, rain, wind, sunlight, etc., which reduces its function as a poster. Among these, deformation such as swelling and wrinkles due to water absorption is a particularly important problem. This deformation due to water absorption is caused by fiber orientation and distortion in the manufacturing process of high-quality paper and coated paper, and is particularly influenced by the drying process. That is, high-quality paper is usually dried in a drying device consisting of multiple cylinders.

This results in a free run or unrestrained portion of the sheet being dried. Due to the orientation of its fibers, paper has the property of shrinking significantly in the lateral direction when water is removed, and on the other hand, when water is absorbed, it stretches and returns to its original state. Therefore, when dried in a free-run state, the sheet shrinks in the transverse direction during drying. In addition, the drying equipment for coated paper uses a hot air dryer or a multi-cylinder dryer, which causes a free run during drying, and the coated paper is also shrunk in the lateral direction, as in the case of high-quality paper. Posters made of high-quality paper or coated paper that have sufficiently shrunk during the drying process absorb water and stretch under the influence of the external environment. This appears as a phenomenon in which the poster bulges and wrinkles appear.

In order to improve the dimensional stability of paper, it is effective to lower the degree of beating of the raw material pulp, but in this case it is not preferable because the paper strength and surface properties necessary for poster paper also decrease. Improvements in the orientation of fibers are also being considered, but at present this is not sufficient from the viewpoint of effectiveness and economy.

- [Means and actions for solving the problem] As poster paper, it can withstand environmental conditions such as rain, functions as a poster, that is, has a good print finish, and can fully demonstrate the display effect, and is disposable, so it is affordable in price. There is a need to develop new products.

In view of these points, the inventors of the present invention conducted extensive research into developing a high-grade poster paper that has high gloss, excellent printing reproducibility, and high dimensional stability.

As a result, it was found that excellent dimensional stability can be obtained even under severe environmental conditions by using single gloss paper made on a Yankee paper machine as the base paper.

Yankee paper machines are different from general paper machines in that the drying process is not carried out using a multi-cylinder dryer, but the main drying device is a single large-diameter dryer called a Yankee dryer. The sheet is wet and is dried in close contact with the surface of the dryer. For this reason, the sheet is dried in a so-called taut state, and shrinkage in the lateral direction during drying is significantly restricted. Therefore, even if water is absorbed again, the elongation in the lateral direction is extremely small, and the elongation of single gloss paper when immersed in water is 40 to 70 that of ordinary high-quality paper.
%.

Typical examples of glossy paper made on a Yankee paper machine include pure white roll paper, nine-sided glossy kraft paper, and pure white wrapping paper.The base paper used in the present invention is made on a Yankee paper machine. There is no particular limitation as long as it is suitable.
゛The present invention uses a single-gloss paper made by a Yankee paper machine as a base paper, and coats at least one side of this base paper with a coating liquid mainly composed of an inorganic pigment and an adhesive by a cast coating method. It is coated and dried to produce poster paper.

The cast coating method is significantly different from conventional coated paper manufacturing methods, especially in the drying process. That is, in the cast coating method, a wet sheet that has undergone a coating process is strongly pressed onto the surface of a large diameter dryer (cast drum) having a mirror surface and is dried. Therefore, based on the same principle as in the case of Yankee Dry Key mentioned above, cast coated paper has extremely good dimensional stability compared to ordinary coated paper.

According to the results of studies conducted by the present inventors, when poster paper is manufactured using the cast coating method, the water immersion elongation in the lateral direction is 20 to 30% smaller than that of the base paper, whereas when poster paper is manufactured using the conventional method of hot air drying. When producing poster paper coated with
% and a decrease in dimensional stability. In other words, even if the same base paper is used, it is obtained by the cast coating method, and
The lateral water immersion elongation is 50~50 compared to that obtained using the conventional method.
There was a difference of 100%, and it was observed that the difference in dimensional change was particularly large in the case of outdoor posters exposed to wind, rain, and direct sunlight.

Various known components can be used in the coating liquid for cast coating used in the present invention. For example, pigments include kaolin, calcium carbonate, aluminum hydroxide, satin white, aluminum silicate, amorphous silica, colloidal silica, etc.; binders include casein,
Soybean protein, starch, carboxymethyl cellulose, polyvinyl alcohol, styrene-butadiene latex, acrylic latex, vinyl acetate emulsion, etc. are used alone or in combination. Furthermore, dispersants and flow modifiers used in general coating fluids.

Various auxiliary agents such as antifoaming agents, dyes, lubricants, and water retention agents can be used.

The cast coated paper thus obtained is strongly pressed against the mirror surface of the cast drum and dried, so that the mirror surface of the drum is transferred to the coated surface, resulting in extremely high smoothness and gloss.

By selecting and combining the base paper and coating process in this way, it has become possible to obtain poster paper that can withstand harsh environmental conditions and has excellent printing reproducibility, which is the object of the present invention.

In order to impart water resistance, the present invention can be made more effective by internally adding a waterproofing agent or size press coating at the base paper stage, or by adding a waterproofing agent to the coating liquid at the coating process stage. Become.

[Examples and effects]

EXAMPLES The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these Examples. In addition, all parts in the examples indicate parts by weight.

Measurements in Examples were performed as follows.

(1) Water immersion elongation: Tested according to method A of J, TAPPI paper pulp test method Nα27. However, only the horizontal direction of the paper was measured, and the immersion time was 1 hour.

(2) Glossiness: 75 degree specular glossiness was measured according to JIS P8142.

(3) Weather resistance: Sunshine Super Long Life Weather Meter (
Manufacturer name, Suga Test Machine, K, equipment name 1i1EL-
3UN-HMC type), and the gloss and surface quality were judged visually. ○: No blisters or wrinkles, the surface is flat, and the appearance is good. Δ: Blisters, wrinkles, or slightly poor appearance. ; The appearance was rated as extremely poor, with blisters, wrinkles, and a lumpy appearance.

Sunshine weather meter processing conditions〉processing temperature
45-50℃ Rainfall cycle: 1 minute 72 hours Processing time: 5 hours (equivalent to about 1 month of outdoor exposure) 15 hours (equivalent to about 3 months of outdoor exposure) (4) Outdoor exposure test: Affix the entire circumference to the exposure table with double-sided tape An exposure test was conducted on the roof of our laboratory for three months, and the surface quality was visually determined.

O: The surface was flat with no blisters or wrinkles.Δ: Blisters, wrinkles, poor appearance.

81 Example 1 Basis weight 105 g/rd, lateral water immersion elongation 1.1
Kaolin (Engelha
rd M&C, trade name, 0l-90) 100 parts, adhesive, styrene-butadiene latex (manufactured by Naugatuck, trade name, 5N307) 10 parts, casein, made in New Zealand, trade name, lactic acid. 9 parts of zein), calcium stearate (as a mold release agent)
A coating liquid with a solid content concentration of 50% containing 2 parts of Nobu Coat Clo4) (manufactured by Sannopco Co., Ltd., trade name) as the main component was coated with a roll coater at a solid content of 20 g/rrl', and then the coating film was coated with zinc formate. A coagulation treatment was performed with a 2% aqueous solution, and while the coating film was in a wet state, it was pressed onto a mirror drum heated to 100° C. and dried to obtain a cast coated paper for a poster.

The results are shown in the table, and the lateral water immersion elongation of the obtained recording paper was 0.8%, and the results of the 'weather meter test and outdoor exposure test showed uniform wrinkles, which would be a problem in practice. However, no deformations such as waving or swelling occurred.

Comparative Example 1 Using the same glossy paper and coating liquid as in Example 1, the paper was coated with a roll coater at 20 g/rr11 in terms of solid content, and then dried with a hot air dryer to obtain a coated paper for a poster.

The results are shown in the table in comparison with Example 1, and the obtained poster paper had a water immersion elongation of 1.6%, and as a result of the weather meter test and outdoor exposure test, there were large deformations such as wrinkles and unevenness. . The aesthetic appearance was poor due to low smoothness and gloss.

Comparative example 2 Basis weight 105 g/rr? , lateral water immersion elongation 2.
Using the same coating liquid as in Example 1 on 6% high-quality paper, use a roll coater to obtain a mirror finish of 20 g/n in terms of solid content. A cast coated paper for a poster was obtained by pressing onto a drum.

The results are shown in the table. The poster paper obtained had a water immersion elongation of 2.1%, and wrinkles and blisters occurred as a result of the weather meter test and outdoor exposure test.

Comparison □Example 3 Using the same high-quality paper and coating liquid as Comparative Example 2, a roll coater was used to achieve a solid content of 20 g/rr? After coating, it was dried with a hot air dryer to obtain coated paper for posters.

The results are shown in the table. The poster paper obtained had a water immersion elongation of 3.2%, and as a result of the weather meter test and the outdoor exposure test, deformation such as wrinkles and blisters occurred.

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Claims (1)

[Claims] 1. Poster paper, characterized in that a coating layer is provided on at least one side of glossy paper made by a Yankee paper machine using a cast coating method.