JPH0366111B2 - - Google Patents

Description

[Detailed description of the invention]

<Technical Field> The present invention relates to a writing material made of a polyester film subjected to sand mat processing. <Prior Art> It is known to project silica sand or glass powder onto the surface of a thermoplastic polymer film using pressurized gas, centrifugal force, or the like to give the film surface a matte finish. Matte-treated film has minute scratches and depressions formed on its surface, and light rays are diffusely reflected on the surface, making the film translucent to opaque. It is possible to print, coat, write, etc. on the surface of the film. This matte processed film has the following required properties (1) to (6). (1) Printing can be done easily and neatly. (2) Good writing quality (3) Less bleeding, blurring, thickening, etc. (4) Less dirt and dust (many have anti-static coating) (5) Good flatness (6) ) Low surface reflection There is a chemical matte processed film that has the same functionality as this sand matte film. This product is obtained by coating the surface of a film with a coating liquid containing a pigment, a polymeric binder, etc., and then drying and solidifying it. Films treated with chemical matte can be printed and written on in the same way as paper, and can be colored arbitrarily or have a high degree of whiteness. Comparing a sand matte processed film and a chemically matte processed film, even if it is uncolored, the sand mat processed film has a slightly lower whiteness. This is not only because a coating film containing white pigment cannot be formed, but also because silica sand and fine glass powder used in the processing process are attached to the surface of the sand mat film. After examining the attached silica sand and glass powder in detail, we found that the whiteness of the surface of the sand-matted film differs depending on the properties of the blasting material used, and we found that the whiteness of the surface of the sand matted film differs depending on the properties of the blasting material used. According to
We have discovered the possibility of obtaining a sand matte processed film with high whiteness. Although matte processed films with high whiteness are suitable for drafting paper, there is a tendency for writing materials with high whiteness to be preferred in terms of appearance. <Object of the Invention> An object of the present invention is to provide a writing material made of a sand matte film with high whiteness. <Structure of the Invention> The present invention is characterized in that the amount of titanium compounds attached to the film surface after sand mat processing is 16 mg as titanium element per unit area (1 m ² ) of the film.
This is a writing material made of the following polyester film. The present invention was confirmed by dissolving a sand matte processed film processed as a writing material in mineral acid, quantifying the titanium compound contained in the film, and analyzing the titanium compound as the amount of titanium element. It is something that will be done. In the present invention, the titanium compound contained in the film refers to a compound that adheres to the surface of the film during sandblasting and dissolves in mineral acid together with the film during analysis. Therefore, it includes all titanium compounds that are simply attached to the film surface, those that are embedded in the film surface layer, and those that dissolve in the mineral acid at the same time as the film. However, in the sandblasting process of polyester film, the silica sand, glass particles, etc. adhering to the film surface hardly fall off even if the surface is washed by normal methods (washing with water, blowing air, etc.).
In the present invention, the titanium compound attached to the film writing material is slightly contained in the silica sand as illuminite (titanite). In other words, the polyester film is sandblasted using silica sand containing illuminite. As a result, sand containing illuminite adheres to the surface of the film, reducing the whiteness of the film writing material. Illuminite contains iron and titanium, and natural silica sand contains about 1/1000 of it (as a titania component). Further, iron oxide components also reduce whiteness on the film surface. The titanium compound contained in the sand or the like adhering to the writing material of the present invention is dissolved in a mineral acid, for example, concentrated hydrochloric acid, while remaining adhering. The amount of titanium element is then measured by metal analysis of the solution. In the method of measuring the titanium element in the present invention, a film is cut into a 5 cm x 5 cm square and immersed in 100 ml of concentrated hydrochloric acid. Usually, it will completely dissolve if left at room temperature for about 1 to 2 days or nights. An applicable method is to measure the metals eluted into concentrated hydrochloric acid and display the concentration of titanium element in ppm. In this measurement method, the elements eluted in concentrated hydrochloric acid include aluminum, calcium, iron, germanium, phosphorus, antimony, tin, zinc, sodium, potassium, and titanium. Among these elements, titanium compounds and iron compounds have a negative effect on the whiteness of the matte processed film. When the titanium compound contains 0.48 ppm or more of the titanium element, the matte processed film has a level of whiteness that is problematic. Experience shows that unless the allowable amount of titanium contained in a film is 0.4 ppm or less, it cannot be treated as a white writing material. The titanium compound attached to the film is preferably 0.3 ppm or less in terms of titanium element. If titanium compounds and illuminite are not attached to this level, sufficient whiteness can be maintained. Iron compounds also have a negative effect on whiteness when attached to the film surface, but iron compounds can be mixed in as iron sand or as illuminite mentioned above, as well as in the manufacturing process. The whiteness of the matte-processed film may be contaminated from manufacturing equipment, and the effect it has on the whiteness of each matte-processed film is different. It is less clear than the relationship. In the present invention, in order to obtain a writing material with high whiteness,
This is achieved by using sand that does not contain illuminite or iron sand during sandblasting. Specifically, iron sand and illuminite are removed from silica sand by magnetic separation using a magnet in a magnetic field of tens of thousands of Gauss and/or by gravity beneficiation by gently pouring it into water. be able to. Incidentally, the specific gravity of silica stone is about 2.65, while the specific gravity of illuminite is about 4.5 to 5.0, so gravity beneficiation is an easy technique to implement. The standard for removing illuminite by beneficiation is to dissolve the film after sandblasting with concentrated hydrochloric acid and check the titanium element content. Since commonly sold silica sand contains illuminite (titanium compound) exceeding this standard, it is difficult to achieve the present invention unless silica sand with a reduced illuminite content is used. <Examples and Reference Examples> A polyester film was sandblasted using silica sand with a different content of illuminite, and this was dissolved in concentrated hydrochloric acid to compare the titanium content and the whiteness of the pine film as seen with the naked eye. . The results are shown in Table 1.

[Table] Next, a small amount of iron sand was mixed with the silica sand of Experiment No. 1, and sandblasting was performed in the same manner as in Experiment No. 1. The resulting pine processed film was dissolved in hydrochloric acid to remove the iron content and the pine film. When considering the color (whiteness), if the iron content is 0.10ppm or less, the film will be matte processed with satisfactory whiteness, but if the iron content exceeds 0.20ppm (same as the film with titanium content exceeding 0.4ppm), the matte processed film will be It was found that the whiteness was inferior. <Effects of the invention> When using silica sand with low iron content and titanium compounds during sandblasting,
The resulting matted film has excellent whiteness. A preferable writing material can be obtained by using a blasting material containing suppressed components that impair whiteness, such as illuminite and iron sand in silica sand.

Claims (1)

[Claims] 1. The amount of titanium compound attached to the surface of the film is 16 per unit area of the film as titanium element.
A writing material made of sand-matted polyester film with a concentration of mg/m ² or less. 2. Claim 1, which consists of a polyester film containing 0.4 ppm or less of titanium element, according to a method of measuring the metal eluted when a film piece cut into a square with a side of 5 cm is dissolved in 100 ml of concentrated hydrochloric acid. writing materials.