JPS58126400A - Map paper excellent in dimensional stability - 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 The present invention relates to map paper that has the characteristics necessary for map paper and has excellent dimensional stability. on a small map paper.

Due to its intended use, map paper is characterized by good printability and excellent folding strength.9 Furthermore, in order to maintain the accuracy of maps, materials with as good dimensional stability as possible are used.

It goes without saying that printability requires surface strength and ink receptivity that can withstand printing, but map paper has fine lines,
The requirements are that characters, etc. be accurately reproduced, and that, in the case of multicolor printing, there will be no misregistration or overlapping of halftone dots.

Poor registration and overlapping halftone dots are phenomena that occur due to various causes, but the characteristics required for paper are desirably low elongation under tensile load.

Additionally, it is not uncommon for maps to be printed in multiple colors, such as six or seven colors, due to their intended use, and maps are often passed through the printing press two or three times.

In this case, misregistration is likely to occur due to changes in the water content of the paper, and the paper is required to have little expansion and contraction due to changes in humidity or moisture.

Regarding the reproducibility of fine lines and characters in printing,
The ink has good adhesion, and the paper surface has good smoothness.
It is also required that the texture be homogeneous.

The properties required after printing include, of course, mechanical strength such as tensile strength and tear strength, but it is particularly desirable that no breakage occurs due to bending, and emphasis is placed on folding strength.

Furthermore, in a map that requires accuracy, the expansion and contraction of the paper itself directly affects the accuracy of the map, so it is required that the expansion and contraction caused by changes in humidity be small.

The paper that is currently generally supplied as map paper does not satisfy these characteristics mentioned above; for example, the paper that is designated by the Geospatial Information Authority of Japan and is used in large quantities uses only wood pulp as its fiber content. However, a very small amount of filler is blended, and a large amount of NBKP is blended as wood pulp, making the paper with emphasis on folding strength, but it generally lacks dimensional stability.

Various methods for imparting dimensional stability have been proposed, and some sheets are commercially available.

For example, if the material is made mainly of wood pulp, a mixture of glass fiber, polyester fiber, and polyolefin fiber is known, and commercially available printing sheets include synthetic paper based on polyolefin.

However, mixed paper made from glass fibers and synthetic fibers often causes uneven printing ink transfer properties and reduced mechanical strength, making it unsuitable for use as map paper.

Synthetic papers based on polyolefins have exceptionally good dimensional stability, but have extremely low tear strength and cannot be folded, which is also a serious drawback.

As a paper that has the characteristics of map paper in a well-balanced manner,
Paper is often provided with a base paper mainly made of wood pulp impregnated with a synthetic resin emulsion, but there are few that can satisfy the ink receptivity during printing, and the dimensional stability is still poor. I'm missing a few steps.

An object of the present invention is to provide a sheet of paper that does not have the above-mentioned drawbacks and has characteristics as a map.

As a result of intensive studies, the inventors of the present invention have found that printing is possible by blending 5 to 40 weight - 31% of fibrillated polyacrylonitrile fibers in a sheet-like material mainly made of wood pulp. Good suitability, excellent mechanical strength,
Moreover, map paper with good dimensional stability was obtained.

Polyacrylonitrile in the present invention refers to fibers made by kneading water-soluble resins such as polyvinyl alcohol, polyacrylamide, and sodium polyacrylate into an acrylonitrile polymer and making fibrillation possible by beating. Fibers having a diameter of 1 denier to 5 denier and a length of 2 to 7 cm are usually provided.

After dispersing this fiber in water, beater, refiner, etc.
Fibrillation is performed using equipment that beats ordinary wood pulp, and the degree of fibrillation can be estimated by freeness.

51 Regarding the paper material formulation for making the sheet according to the present invention, the dimensional stability depends on the blending amount of the above-mentioned polyacrylonitrile fiber, and it goes without saying that the larger the blending amount, the worse the paper stock composition. It also depends on the degree of fibrillation, and the more fibrillation progresses, the better it will be with a smaller amount of blending.

In the present invention, when polyacrylonitrile fibers with advanced fibrillation are used, the dimensional stability is greatly improved when the fiber content exceeds 5% by weight, especially KIO, and the fibrillation is not too advanced. Even when using non-containing fibers, map paper with good dimensional stability could be obtained with a fiber content of 30 parts by weight or less.

In the present invention, the reason why fibrillated polyacrylonitrile fibers are used is to impart mechanical strength; if non-fibrillated fibers or slightly fibrillated fibers are used, mechanical strength will decrease. If the degree of fibrillation is 300 or less in terms of Canadian freeness, a paper with good mechanical strength can be obtained.

Next, the method for manufacturing map paper according to the present invention will be described in detail.

The present invention provides an aqueous dispersion of moderately beaten wood pulp.
The main idea is to mix an aqueous dispersion of fibrillated polyacrylonitrile fibers and make paper, but fillers, chemicals, etc. are added depending on the desired pressure.

In addition, the surface is treated with a size press coater, air knife coater, etc. to provide printability, and a smooth finish is applied with a super calendar, cross calendar, etc. to provide smoothness, making it suitable for use as map paper. Grant.

The thus obtained map paper had a smooth surface, good printability, excellent mechanical strength including folding strength, and good dimensional stability, all of which are necessary characteristics for a map paper.

The present invention will be explained below by giving examples.

Examples 1 to 3 Symmetrical examples 1 to 3 150 tn was added to NBKP beaten to 450rntcaf.
Cashmilon A-104 beaten to tcaf (Asahi Kasei, beatable polyacrylonitrile fiber 1.5d B m length)
Thoroughly mix and add to this, based on 100 parts by weight of fiber,
2 parts of melamine resin, 2 parts of rosin size, 2 parts of sulfate
1 part and 8 parts of titanium were added to prepare a paper stock.

The fiber compositions of Examples 1 to 3 and Symmetrical Examples 1 to 3 are shown below. Shown in 1.

The prepared sample was processed using a long steel paper machine to produce 791/zede chichise 2.4.
F/& was applied and smoothed using a machine calender to produce map paper.

Table 1 shows the physical property values of the map paper according to the present invention and the comparative example thus obtained.

From Table 1, it is clear that the map paper produced by the method of this example has good dimensional stability and mechanical strength.

Examples 4 to 6 Symmetrical Example 4 This example and symmetrical example show the influence of the freeness of Cashmi O 7A-104 on its physical properties.

The wood pulp was mixed with 80 parts of NBKP with a beating degree of 450 GCSF and 20 parts of Kashi Kenronjin-104 which had been beaten with a heater.

All other additives, paper making method, processing method, and smoothing finish were carried out in the same manner as in Example 1.

Table 2 shows the fiber composition, freeness and characteristic values of Cashmilon A-104.

From Table 2, it is clear that the map paper according to the present invention has excellent dimensional stability and mechanical strength, and has the characteristics as a map paper.

The expansion/contraction rate indicates the rate of dimensional change when the sample is left in an environment ranging from a temperature of 20° C. and relative humidity of 30% RH to a temperature of 20° C. and relative humidity of 90% RH.

Underwater elongation indicates the dimensional change at the time of death when the sample is immersed in water for 10 minutes.

Re-rolling shrinkage refers to the dimensional change when a sample subjected to underwater elongation is air-dried.

The tensile elongation is 9- when a load of 4 edges/piece is applied to the sample. This shows the elongation rate of the sample.

Table-1 10- Table-2 -11- 630-

Claims (1)

[Scope of Claims] 1. A map paper with excellent dimensional stability, which is a sheet-like material mainly made of wood pulp, which is characterized by containing 5 to 30% by weight of fibrillated polyacrylonitrile fibers as a fiber component. . λ Fibrillated polyacrylonitrile fiber is
The map paper according to claim 1, which has a density of 300 dcsf or less as measured by Canadian Freeness.