Application of the most popular non diazo naphthoq

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Application of non diazo naphthoquinone positive PS version (I)

I. preface

since the invention of diazo naphthoquinone positive PS version by Carlyle company in Germany in the 1930s, this version has been successfully used for nearly 70 years and has become a cross century version with a long history. So far, almost all the photosensitive components of positive PS plates used in the world are systems in which diazo naphthoquinone sulfonate is a photoactive compound as a solvent inhibitor. Especially in China, it is the only photosensitive component of Yangtu PS edition (Miyazawa Huiyan: introduction to PS edition, publishing department of Japan printing society, 1993). Although there are many studies on the photosensitive components of positive PS plate, for example, in the 1960s and 1970s, people once studied the photosensitive component system of poly (phthalaldehyde) positive PS plate; After IBM invented the chemical amplification resist in the 1980s, it tried to transplant it to the production of Yangtu PS plate, but at that time, these systems either made the cost of photosensitive components too high because of the expensive raw materials, or because the plate making process became more complex, and the comprehensive performance of the plate was not better than the original diazonadione PS plate, so in addition to the promotion and application of photoresists, It has not been popularized and applied in Yangtu PS version. However, in the 1990s, the principle and design idea of chemical amplification resist were popularized and applied in thermal CTP plate

in 1990, Dennis et al. Of 3M company disclosed the patent of using diphenylacetic acid photoactive ester compound as the solvent inhibitor of PS plate photosensitive composition. However, this photoactive compound (PAC) has the following disadvantages as a solvent inhibitor: first, its impact function is the most important trade-off. According to the fact that the compound itself is a low viscosity liquid, and it is easy to dissolve in many organic solvents, especially in the printing ink solvent, it has a certain solubility, and the PS plate coated with it as a photosensitive component has very low printing resistance; Another big disadvantage is that the storage stability of this compound is very poor. It is found that it automatically decomposes into diphenylacetic acid after storing at room temperature for several weeks. So although I applied for a patent, I never saw the commercialized PS version

in recent years, in order to meet the needs of users for high sensitivity plates, especially for the requirements of CTCP plate making machine for high sensitivity plates, Agfa company has launched P-51 and P-61 high sensitivity positive PS plates, KPG has launched VI to complete the functions of pulling, pressing, bending, shearing, peeling, tearing, friction coefficient, modification, etc., rage positive PS plates, Fuji company has launched VQ positive PS plates, and some companies are also actively developing them. Most of these new plates are non diazo naphthoquinone series

recently, we have developed a new type of non diazo naphthoquinone positive PS plate photosensitive composition based on the basic principle of acid-base amplification at room temperature in chemical amplification resist. The sensitivity, printing resistance, contrast and development tolerance of the positive PS plate coated with it and the b/p value of the formula are higher than those of the traditional diazo naphthoquinone positive PS plate, It has a good prospect of industrialization and commercialization

II. The basic principle of the new non diazo naphthoquinone positive PS plate photosensitive composition

as mentioned above, its basic principle is that the electrical system of the dynamometer of the hydraulic universal testing machine based on Jinan new era Gold Testing Instrument Co., Ltd. is mainly used to realize the start, stop, forward and reverse rotation of the motor on the oil pump and the beam, as well as the short circuit, overload protection and mechanical limit protection of the motor. It is used in the chemical amplification resist, In particular, the recent basic principle of acid catalytic growth at room temperature. In the photosensitive composition, the photoactive compound used, that is, the blocking solvent, is a linear phenolic resin or a linear polymer with carboxyl groups linked on the side. Some ketal or acetal protective groups are used to protect the alkali soluble phenolic hydroxyl or carboxyl groups to become the blocking solvent of the photosensitive composition, and the photosensitive composition is formed by combining the synthetic film linear phenolic resin and the photoacid source. When the photosensitive layer of PS plate is exposed through the film, the acid source of the light receiving part decomposes to produce acid, and the generated acid can immediately remove the protective group at room temperature, releasing phenolic hydroxyl or carboxyl groups, so that the photoactive compound changes from insoluble to solubilized, and the positive image is obtained by developing with alkali developer. The principle of photoactive compounds from solubilization inhibition to solubilization promotion

III. performance characteristics of new non diazo naphthoquinone positive PS version

1 High sensitivity

the diazo naphthoquinone positive PS version used in the past has low sensitivity, and the general imaging exposure is 200 ~ 400mj/cm2. The VPS version of Fujifilm company and the YPS version of the second film factory of Lucky Film Group are among the PS versions of high sensitivity diazo naphthoquinone positive image, with an imaging exposure of 100 ~ 150mj/cm2. The imaging exposure of the new non diazo naphthoquinone positive PS version developed by us is less than 50mj/cm2, and some can be as low as 10mj/cm2. Compared with diazo naphthoquinone positive PS plate, the sensitivity is much higher, which not only meets the requirements of newspaper printing houses and other users for high sensitivity of PS plate, but also meets the requirements of CTCP plate making machine system for high sensitivity of plate

2. Good resolution and point reduction

the resolution of the traditional diazo naphthoquinone positive map PS version is excellent, and this system is at the same level as the diazo naphthoquinone positive map PS version. If the Ra value of aluminum plate base is about 0.5, the RH value is 2 ~ 4 μ M, the anodic oxide film is 2 ~ 4g/m2. Coating a photosensitive layer of about 2g/m2 on such an aluminum plate base, its resolution can be greater than 250 lines/inch, and the minimum resolution line width can reach 6 μ M, it can clearly reproduce 2% - 98% of the points. If the exposure and development conditions are well mastered, 1% - 99% of the points can be reproduced

3. High contrast( γ High value)

for positive resist and photosensitive composition of positive PS plate, theoretically speaking γ The higher the value is, the better. If the gray scale is used for exposure and development to detect, the less the number of transition segments is, the better. If a gray scale with a differential optical density of 0.15 is used for exposure and development, under the most suitable exposure and development conditions, the number of transition segments of diazo naphthoquinone positive PS version is generally 4 ~ 5, which is the range of most domestic PS versions, and some of the transition segments of PS version with contrast are as high as 6. Fujifilm's VPS version has a good contrast, with only 2 ~ 3 transition sections. The so-called number of transition sections refers to the number of sections (4 sections) between the highest section (e.g. 3 sections) of the number of cleaning sections and the highest section (e.g. 7 sections) where very slight film disintegration occurs. This evaluation method is basically consistent with the number of transition segments observed after printing ink. Some people regard the difference between the maximum number of discoloration and the maximum number of cleaning as the number of transition sections, which often produces a large deviation. Because now PS version generally adopts the technology of adding or subtracting colors. In this case, a large number of discoloration segments are observed. In fact, the discoloration does not necessarily occur. It still has good ink absorption. After inking, it is covered by ink, so the number of transition segments observed will be less than the actual number. The number of transition segments of the new system we developed is generally less than 3, and in some cases it is 1 or 0

4. Weak or you need to adjust the control parameters of the experimental machine (i.e. the conventional P, I, D parameters) at any time for alkali development. The development tolerance is large

developing with weak alkali is a major advantage of diazo naphthoquinone PS version. Our new positive PS version can be developed with diazo naphthoquinone PS version developer. Fujifilm's VPS version has a very large development tolerance. Images can be quickly developed in the matching developer (DP-4) with a dilution ratio of 1:4. If the development time is extended, clear images can also be developed in the developer of 1:10. The YPS version of the second film factory of lucky group also has similar characteristics. It can be developed in a dilution of 1:5 to 1:12 with the matching positive PS version developer. The new plate can be developed with this developer, and its dilution ratio can be arbitrarily selected from 1:3 to 1:6. It is planned to further improve the development tolerance in the future. Such a large development tolerance can effectively extend the service life of the developer and reduce the three wastes pollution caused by the discharge of waste developer. There is still a certain gap between the domestic general PS version and the above tolerance. This kind of new material has another feature: when it is developed for a certain period of time at an appropriate development concentration and temperature, the development time will be extended, and only the transition section will be washed away. The number of washed segments remains unchanged, so the transition segment of 1 segment or 0 segment can be obtained

(to be continued)

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