JP2572222B2 - Plate material for offset printing - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an offset printing plate comprising an olefin polymer having a sulfonic acid group on the surface.
More specifically, the present invention relates to an offset printing plate material that is sensitive not only to low-output laser light in the visible and near-infrared regions but also to a thermal head such as a thermal printing device and does not require development and fixing processes. .

[Conventional technology]

Conventionally, a method of obtaining a printing plate used for offset printing includes (1) a so-called PS plate method, (2) a silver salt photographic method represented by a silver master method, and (3) an electrophotograph represented by an electrofax method. Laws, etc. have already been developed and commercialized.

However, these methods require a step of obtaining a printing plate after forming a latent image by exposure, developing and fixing, and the plate making process is complicated, and the plate making machine itself becomes large, and In addition, there are problems such as soiling of hands in handling the developer.

The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, have invented a method of manufacturing an offset printing plate that does not require processing steps such as development and fixing, and have previously filed a patent application ( See Japanese Patent Application Laid-Open No. Sho 60-102632 and Japanese Patent Application Laid-Open No. Sho 60-132760).

[Problems to be solved by the invention]

However, since these printing plates also require high energy density of light energy, practically, for example, a xenon flash lamp of several hundred watts or a laser oscillator having an output of several watts or more must be installed. There was a point that needed to be improved.

The present invention is to greatly improve the plate making of the offset printing plate material having the hydrophilic sulfonic acid group,
For example, a 10-mW output He-Ne laser, a simple and compact thermal printer such as a word processor, or a printing device using a thermal facsimile to perform a printing operation to obtain an offset printing plate,
And a heat-sensitive plate material.

[Means for solving the problem]

That is, the present invention is a film or sheet of an olefin-based polymer having a sulfonic acid group provided on its surface by a sulfonation reaction, and in an infrared absorption spectrum of the surface, the film or sheet is attributed to a sulfonic acid group having a wave number of around 1200. Another object of the present invention is to provide an offset printing plate material characterized in that the ratio between the absorbance of a strong band and the absorbance of a band belonging to a sulfonic acid group having a wave number of around 1050 is at least 0.6.

As the olefin polymer used in the present invention, for example, one selected from olefin compounds such as ethylene, propylene, butene-1, 4-methylpentene-1, hexene-1, octene-1, butadiene, and the like, or It is a product obtained by polymerizing two or more types of monomers, and preferably has a water absorption of 2.0% or less. In general, polymers such as vinyl sulfonic acid and other polymers or copolymers that originally have sulfonic acid groups, or those obtained by applying these polymers to other base fabrics, have a large water absorption rate and are therefore dimensionally stable. It is excluded because it is not suitable for use as a printing plate material due to reduced properties. The water absorption here refers to the rate of weight increase when immersed in water at a temperature of 20 ° C. for 24 hours.

Similarly, a polymer compound having a water absorption of 2.0% or more is not suitable because the dimensional stability of a printing plate obtained by sulfonation is low.

These polymer compounds may be used as a composite material by laminating a film or sheet with another substrate, for example, paper, glass cloth, glass paper, aluminum plate, or the like.

There is no particular limitation on the method of sulfonation.For example, the film or sheet may be immersed in fuming sulfuric acid, or sulfuric anhydride may be used as it is or in chloroform, carbon tetrachloride, sulfuric anhydride such as ethylene dichloride, etc. On the other hand, it may be diluted with an organic solvent having relatively low activity.

Sulfonation conditions vary depending on the type of polymer used, but by performing the reaction using an oxidized sulfonating agent such as sulfuric anhydride, a structure having a strong band at a wave number of around 1200 in the infrared absorption spectrum is obtained. You can get things. This band indicates that at least a sulfonic acid group adjacent to a polyene structure having three conjugated double bonds has been formed, and it has been found that the sulfonic acid group exhibits photosensitivity or heat sensitivity. Was completed.

That is, the amount of the sulfonic acid group, compared with the amount of the general sulfonic acid group attributed to the wave number 1050, when the absorbance ratio is 0.6 or more according to the present invention, or offset excellent in heat sensitivity and heat sensitivity. Give a printing plate. Such an excellent printing plate material of the present invention can be obtained by appropriately selecting the sulfonation temperature and time when an oxidized sulfonating agent is used.

That is, in order to increase the ratio of the formation of sulfonic acid groups adjacent to the polyene structure, it is desirable to lower the sulfonation temperature, and the reaction temperature is usually −
30-70 ° C, preferably 0-40 ° C. If the sulfonation temperature is 70 ° C. or higher, various side reactions are likely to occur, and are excluded. On the other hand, at -30 ° C or lower, when used in the form of sulfuric anhydride gas, the gas is liquefied and adheres to the inlet pipe wall, so that process abnormalities are likely to occur, and the generation rate of sulfonic acid groups adjacent to the polyene is reduced. It is removed because it is slow and economically unfavorable.

On the other hand, the sulfonation time must be selected depending on the temperature, for example, 5 to 60 minutes at 0 ° C. and 1 to 40 ° C.
30 minutes is a preferred range.

In addition, other oxidizing low sulfonating agents generally used industrially, such as chlorosulfonic acid, phosphoric sulfonic acid, adducts of sulfuric anhydride with dimethylformamide or dioxane, etc., are adjacent to the polyene structure. Since the production amount of general sulfonic acid groups is superior to the production of sulfonic acid groups, it is difficult to increase the absorbance ratio to 0.6 or more, and special measures are required.

When the amount of sulfonation is 5 × 10 ^-5 to 1 × 10 ^-1 meq / cm ² in exchange equivalent, it gives hydrophilicity necessary for forming a non-image portion in an offset printing plate, and generally, As the amount of sulfonation increases with the progress, the hydrophilicity also improves, but the ratio of the absorbance is not always linear with the amount of sulfonation, so the optimal conditions must be selected for each polymer. . The amount of sulfonation is determined as follows. That is, a film whose surface is sulfonated (surface area: Mcm ² ) is immersed in a 1N aqueous solution of calcium chloride to make an equilibrium state, and hydrogen chloride generated in this aqueous solution is converted into a 0.1N aqueous solution of sodium hydroxide (titer: f ) And neutralize with the indicator phenolphthalein (Xc
c) is calculated and calculated by the following equation.

Sulfonation amount (milli-equivalent / cm ² ) = (0.1 × f × x) / M The absorbance ratio referred to in the present invention is determined by using a baseline method generally adopted in the analysis of infrared absorption spectrum. That is, the wave number 1050 and attributed to the sulfonic acid group
Strong band around 1170 and wave number 1200 specified by the present invention
The ratio of the absorbance of the corresponding band is determined based on the baseline common to the nearby strong bands. The infrared absorption spectrum of the sulfonated compound can be measured by a reflection method (ATR method). It is known that non-photosensitive general sulfonic acid groups usually show two strong bands characteristic around the wave number of around 1050 and around the wave number of 1170, but further around the wave number of around 1200, preferably around the wave number of around 1200 to 1230. It has a photosensitive sulfonic acid group showing a similar strong band. It is the above-mentioned sulfonate, which is attributed to a photosensitive sulfonic acid group having a wave number of around 1200. When the ratio between the absorbance of the band and the absorbance of the band attributable to the sulfonic acid group having a wave number of about 1050 is 0.6 or more, the high-sensitivity offset printing plate material intended for the present invention is provided. It is generally difficult to obtain one having an absorbance ratio of 2.3 or more, and the absorbance of a sulfonate having the sensitivity required for plate making using a widely used thermal head is preferably 1.1 to 1.8.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 A reaction vessel in which a high-density polyethylene film (average molecular weight: about 100,000) having a thickness of about 200 μ was set in a dried glass vessel was cooled from the outside so that the internal temperature was 0 to 5 ° C. On the other hand, sulfuric anhydride gas obtained by introducing dry nitrogen gas from the outside into a gas generator containing sulfuric anhydride is cooled from the outside so that the temperature becomes 0 to 5 ° C., and introduced into the reaction vessel. The reaction was performed for 25 minutes. After the completion of the reaction, the film was taken out of the container, washed with water, and dried.

The sulfonation amount of this film is 7.2 × 10 ^-4 meq / cm
^2. The absorbance ratio of the infrared absorption spectrum was 1.7.

 The above film was stuck on a rotating roll and helium-
Roll the light focused to a neon laser beam diameter of 40μ
Irradiation was performed at a peripheral speed of 50 cm / sec. Meanwhile, another said
The film was converted to a word processor (Sharp; Shoin)
, Model WD-300F) and print with a thermal head.
Was. Offset printing of the plates prepared in this way
After printing on the machine, the former had a line width of 45μ.
In the latter case, sharp characters were obtained.

Example 2 A high-density polyethylene film having a thickness of about 200 μm and used in Example 1 was set to a predetermined reaction temperature and reaction time, sulfonated according to the method of Example 1, washed with water, and air-dried. Then, it was set in a word processor and printed using a thermal head. The printing plate thus obtained was mounted on an offset printing machine and subjected to a printing test to obtain the results shown in the following table.

Example 3 The high-density polyethylene film having a thickness of about 200 μm used in Example 1 was immersed in fuming sulfuric acid containing about 15% of sulfuric anhydride at 0 ° C. for about 20 hours to perform a sulfonation reaction. After completion of the reaction, the mixture was sufficiently washed with water, neutralized with 1N sodium hydroxide, and air-dried. The sulfonated amount of this film was 8.2 × 10 ⁻³ meq / cm ² , and the absorbance ratio was 0.7.

Next, this film was affixed to a rotating roll, and a beam focused to a beam diameter of 40μ of a yag laser (NEC; SL129, output 50mw) was irradiated at a circumferential speed of the roll of 100cm / sec, followed by offset printing. This gave a clear image of about 36μ.

Example 4 Ethylene having a thickness of about 150 μm and a size of B-4,
A linear low-density polyethylene film of methylpentene-1 (3 mol%) (average molecular weight: about 30,000) was subjected to a sulfonation reaction under the same reaction conditions as in Example 1 for 20 minutes, washed with water, and air-dried. The amount of sulfonation of this film is 1.4 × 10
^{At -3} meq / cm ² , the absorbance ratio was 1.2.

After printing the film for 20 seconds using a line printer having a thermal head of 4000 dots per 250 mm, offset printing was performed in the same manner as in Example 1 to obtain a clear printed matter.

Example 5 A polybutene-1 film (average molecular weight: about 50,000) having a thickness of about 100 μ was immersed in an ethylene dichloride solution containing about 10% of sulfuric anhydride at 0 ° C. for about 40 hours to perform a sulfonation reaction. After the completion of the reaction, the resultant was sufficiently washed with water and air-dried. The sulfonated amount of this film was 1.6 × 10 ⁻⁴ meq / cm ² , and the absorbance ratio was 1.2.

Then, printing was performed using a word processor in the same manner as in Example 1, and offset printing was performed. As a result, clear characters could be printed.

〔The invention's effect〕

By using the offset printing plate material of the present invention,
As described above, a printing plate can be easily manufactured. Therefore, for example, when a reading and writing mechanism of a facsimile and an offset printing machine are connected via the printing plate material of the present invention, printing of high-quality characters (mass copying) as a fully automatic printing machine is performed. Can be easier. Furthermore, since a computer (workstation) having an editing / composing function and an offset printing machine can be easily connected, a simple plate making /
The present invention has many advantages, such as the ability to provide a printing system.

Claims (1)

(57) [Claims] An olefin polymer film or sheet having a surface provided with a sulfonic acid group by a sulfonation reaction, which is attributed to a sulfonic acid group having a wave number of about 1200 in an infrared absorption spectrum of the surface. A plate material for offset printing, wherein the ratio between the absorbance of a strong band and the absorbance of a band belonging to a sulfonic acid group having a wave number of around 1050 is at least 0.6.