JPS5815786B2 - How to stake out - Google Patents

Description

[Detailed description of the invention] The present invention relates to a tensioning method.

More specifically, it is an object of the present invention to provide a method for attaching an original image to a film in printing or plate making, such that the transmitted image is clear and interference fringes are not generated.

As is well known, in the printing and plate-making process, one or more original drawings such as photographs are pasted onto a stretching film, and this is used to create other original drawings for layout or layouts. There is a process.

The stretched film used here not only has excellent dimensional stability and is not easily charged, but also has a clear transmission image and is capable of forming a transmission image without interference fringes between the original image and the film. Characteristics such as non-interference are required.

By the way, in order to make a transmitted image clear, it is best to avoid containing foreign matter that would impede transmission, and such a film can be manufactured from a polymer that does not contain fine particles. The surface of the film is very smooth.

On the other hand, it has been found that the occurrence of Newton's rings in interference fringes is due to too close contact between the film and the original image.

Therefore, in order to prevent the occurrence of interference fringes, it is considered preferable to increase the surface roughness to a degree or more so that the original drawing and the tensioning film do not come into too close contact with each other.

Such a film can be obtained by forming a polymer containing fine particles (for example, kaolin, etc.) and stretching (for example, biaxial stretching), but the film obtained in this way has a lower transparency. , when used for embedding, the transmitted image becomes unclear.

As described above, the conventionally known methods have the disadvantage that it is not compatible with making the film transparent to make the transmitted image clear and suppressing the occurrence of interference fringes.

As a result of intensive research into a tensioning method that does not have such drawbacks, the present inventor found that the front and back surfaces of the film have different smoothness, the surface roughness of the rough surface is 0.10μ or more, and the haze of the film ( It was discovered that if the original image is pasted onto the rough side of a plastic film where the product of the coefficient of static friction (unit: %) and the coefficient of static friction is 2 or less, interference fringes can be prevented and the transmitted image can be kept clear, and the present invention has been made. reached.

That is, in the present invention, the surface and back surfaces of the film have different smoothness, the surface roughness of the rough surface is 0.10μ or more, and the product of the film haze (unit: %) and the coefficient of static friction is 2 or less. This pasting method is characterized by pasting an original drawing onto the rough side of a plastic film.

The plastic film used for pasting the original drawing in the method of the present invention may be made of a crystalline thermoplastic resin, such as aromatic linear polyester, polyamide, high-density polyethylene, or tactical polypropylene (even if it is copolymerized as long as it does not lose its crystallinity). good.

), particularly aromatic linear polyesters (e.g. polyethylene terephthalate, polyethylene-
A biaxially stretched film of (2,6-naphthalene dicarboxylate, etc.) is preferred because it has excellent dimensional stability and other physical properties.

The film used for tensioning in the method of the present invention has a front surface and a back surface with different smoothness, the surface roughness of the rough surface is 0110μ or more, and the product of the film haze (unit: %) and the coefficient of static friction is 2. These are as follows.

It is necessary that the rough surface has a surface roughness of 0.10μ or more, preferably 0.15μ or more.

If it is smaller than 0.10μ, it is not preferable because it is impossible to prevent interference fringes from being generated during embedding.

The surface roughness of the smooth surface of the film may be smaller than that of the rough surface, but is preferably 0.09 μm or less.

Further, the product of the degree of haze (unit/%) and the coefficient of static friction must be 2 or less, but preferably 1.5 or less.

If this value is thicker than 2, the transmitted image will become unclear or the slipperiness of the film will deteriorate, making it difficult to handle the film, which is not preferable.

The thickness of the film used in the method of the present invention is not particularly limited, but it is usually 25 to 350μ, particularly 50 to 250μ.
00μ is preferable.

In addition, the above-mentioned 1. surface roughness, haze, and static friction coefficient are measured by the following method.

[Surface hardness] Using a stylus type surface roughness tester, the stylus radius was 2.5μ and the load was 0. IP,
It is expressed by the 10-point average roughness determined according to JIS-B-0601 under the condition of a reference length of 0.25 mm.

[Cloudiness]

Measured according to JIS-6174, percentage (unit:
%).

[Static friction coefficient]

ASTM-D-18 between the smooth and rough sides of the film.
Values measured according to 94.

Such a film may be selected from films whose front and back surfaces have different degrees of smoothness, less haze, and a lower coefficient of static friction.

In order to produce a film with different smoothness on the front and back surfaces, less haze and a lower coefficient of static friction, for example, one side of a substantially amorphous unoriented film is brought into contact with water vapor,
What is necessary is to adopt a method of orienting this and heat-setting it.

Conventionally known methods such as melt extrusion-quenching, solution casting, etc. can be used to form a film.

In forming the raw film, it is desirable to form the film so that the degree of crystallinity of the film is as low as possible in order to obtain the transparent film of the present invention.

Polyethylene terephthalate, polyethylene-2/6-
In the case of naphthalate, the degree of crystallinity is preferably about 10% or less.

For the steam treatment of the substantially amorphous unstretched film made of the crystalline thermoplastic resin, a method is adopted in which the surface of the film is introduced into a steam atmosphere, or the surface of the film is moistened with water at 100° C. or less and then heated. can.

The surface of the film to be treated is brought into a state where water vapor and temperature promote crystallization.

That is, in the case of polyethylene terephthalate, the temperature of the surface in contact with water or steam is 100°C to 250°C.

If the temperature is too low or too high, the crystallization promoting effect disappears, which is not preferable.

Processing time is related to film temperature.

Preferably, the time is such that the inner layer of the film not in contact with water vapor is within the crystallization induction period and the crystallinity does not begin to increase.

Although only one side is treated with steam, the slipperiness is significantly improved.

As mentioned above, by bringing the surface of a substantially amorphous unstretched film into contact with water vapor, the film surface layer receives a crystallization promoting effect, and by stretching this, fine irregularities are generated on the steam-treated surface, and the slipperiness is significantly reduced. Improved.

The inner layer, which has not been exposed to water vapor and has not crystallized, is normally stretched into a transparent film.

The unsteamed surface remains substantially smooth after being stretched.

Orientation of the steam-treated unstretched film may be performed by a conventionally known method.

For example, uniaxial stretching, sequential biaxial stretching, simultaneous biaxial stretching, etc. can be employed.

The orientation conditions may be those that ordinarily orient a raw film that has not been subjected to steam treatment.

That is, since it is only the surface layer of the film that receives the crystallization promoting action by the water vapor treatment, the orientation conditions may be approximately equal to -1 or slightly adjusted.

Heat setting is carried out if necessary to improve the dimensional stability of the obtained film.

For this method, a conventionally known method may be adopted.

The thermoplastic resin used as a raw material for producing such a film preferably does not contain insoluble fine particles, but may contain a small amount of insoluble fine particles as long as the above-mentioned properties of the film are not impaired.

In the method of the present invention, an original image is pasted onto the rough surface of a film having the above characteristics.

A conventionally known method may be used for the mounting method.

In the method of the present invention, since the original image is pasted onto the rough surface side of the film having the above-mentioned characteristics, the original image and the film surface do not come into close contact to the extent that interference fringes occur.Moreover, the transparency of the film is excellent, so that the transmitted image cannot be seen. It's clear.

In other words, it has the characteristic of being able to achieve both "prevention of interference fringes" and "clearness of transmitted images," which were difficult to achieve in the past.

In addition, the film itself has excellent slipperiness, making it easy to wind up and handle in other ways, and the knurling part (thickened part provided at the edge of the film) that is required in the case of normally obtained transparent films. There is no need to provide
The yield of the film itself is also excellent.

The present invention will be explained in detail below using specific examples.

Comparative Example 1 A film was formed using a conventional method using polyethylene terephthalate polymerized using a catalyst soluble in the polymer as a raw material.
Sequentially biaxially stretched 3.2 times in length and 3.5 times in width at 05°C.
A film with a thickness of 100 μm was produced by heat setting at 0° C., but the film had poor slipperiness and could be wound up by providing a knurling portion.

This film had a haze degree of 1.3%, a coefficient of static friction of 4 or more, and a smooth surface roughness of 0.06 μm on both the front and back surfaces.

When the original drawing was pasted onto this film, the original drawing and film came into close contact, and interference fringes were observed.

Examples 1-2 The same polyethylene terephthalate used in Comparative Example 1
A polymer film was formed under the same conditions as in Comparative Example 1 to produce an unstretched film.

The film is coated with fluororesin and the surface temperature is 102℃.
At the same time, superheated steam at 300°C is applied to the opposite side of the film for a predetermined period of time
(See Table 1) After spraying, 32cm vertically at a temperature of 90-105℃
Sequentially biaxially stretched to 35 times in width and 35 times in width, heat set at 220℃,
A film with a thickness of 100μ was obtained.

The obtained film can be used without knurling.
I was able to wind it up easily.

Table 1 shows the physical properties of the film.

When original images were pasted onto the rough side of these films, no interference fringes were observed and the transmitted images were clear.

Comparative Examples 2-3 When the original image was pasted onto the smooth surface side of the film produced in Examples 1-2, the original image adhered to the film and interference fringes were observed.

Comparative Example 4 A film with a thickness of 100μ was prepared in the same manner as in Comparative Example 1, except that instead of the polyethylene terephthalate used in Comparative Example 1, 0.05% by weight of finely divided kaolin (average particle size 1μ) was used. Manufactured.

The surface roughness of the obtained film was 0.19 on both the front and back surfaces.
μ, haze was 6.9%, and static friction coefficient was 0.40.

When the original image was pasted onto this film, no interference fringes were observed, but the transmitted image was unclear due to the poor transparency of the film.

Example 3 Film formation, steam treatment, and stretching were performed in the same manner as in Example 1, except that fine-particle silica (using Aerosil) and polyethylene terephthalate containing O and OS weight % was used as the raw material polymer.

The surface roughness of this film is 0.18μ on the rough side and 0.08μ on the smooth side, the haze is 2.9%, and the coefficient of static friction is 0.4.
It was 5.

When an original image was pasted onto the rough side of this film, no interference fringes were observed and the transmitted image was clear.

Comparative Example 5 Example 3 except that the unstretched film was not subjected to steam treatment
The biaxially stretched film obtained in the same manner as above had a surface roughness of 0.08μ on both the front and back surfaces, a haze level of 2.3%, and a coefficient of static friction of 1.5.
Met.

In order to wind this film smoothly, it was necessary to provide knurling.

When the original image was pasted onto this film, interference fringes were observed.

Claims (1)

[Claims] 1 Roughness of a plastic film in which the front and back surfaces of the film have different smoothness, the surface roughness of the rough surface is 0.10 μ or more, and the product of the film haze (unit: %) and the coefficient of static friction is 2 or less. A embedding method characterized by embedding the original drawing on the surface side.