JP2008156429A - Varnish for infiltration-drying type offset ink, and ink by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide varnish for infiltration-drying type offset ink used for a low class paper excellent in solving a problem of paper peeling in a high speed-printing of recent years, and the ink by using the varnish. <P>SOLUTION: This varnish for the infiltration-drying type offset ink is provided by using a rosin-modified phenol resin having the molecular weight made as a high molecular weight of 70,000 to 1,200,000 not used conventionally as the varnish for the offset-printing ink and also having the dissolvability without forming turbidity in 10 to 35 wt.% solution of the varnish with a 15C aliphatic hydrocarbon at 25°C. By using such the varnish as the penetration-drying offset-printing ink composition, especially on the high speed-printing, it becomes possible to satisfy printing aptitude excellent in solving the problem of the paper peeling. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a osmotic drying type offset ink varnish and an ink using the same, and particularly to a osmotic drying type offset ink varnish excellent in solving the problem of paper peeling at high speed printing, which is likely to occur in low-speed paper printing at the time of high speed printing. The present invention relates to an ink using.

  In recent years, the printing speed has been increasing, but as the printing speed increases, the tackiness of the ink increases, so osmotic drying using low-grade paper with weak paper strength such as newspapers, comics, and weekly magazines. In mold offset printing, the paper is likely to peel off.

  Furthermore, conventionally, various improvements have been made as a method for reducing the tack value in the ink for penetrating dry type offset printing. Kneading of extender pigments such as calcium carbonate, organic bentonite, silicon dioxide, etc. more than usual to reduce tack, is effective in reducing tack, but lowers the fluidity of the ink, There is a risk of poor inking due to deterioration. In addition, extender pigments are generally hard and difficult to finely disperse, and coarse particles may remain in the ink. The coarse particles adversely affect the printing plate, blanket thick cylinder, guide roll, etc., and promote plate wear. This causes printing defects such as blurring of lines and rubbing stains due to accumulation.

  As a resin to be included in the varnish for offset printing ink, a rosin-modified phenol resin is generally used because of its excellent printability, but the amount of gelling agent used for varnishing is more than usual. However, it has been studied to reduce the ratio of the resin contained in the varnish and reduce tack, but it is likely that the ink will become excessively emulsified, causing printing troubles such as water rod entanglement and reduced transferability. It may become.

  In addition, studies aiming to reduce the tack value by reducing the resin ratio in the varnish by polymerizing the resin itself used in the varnish have been performed. For example, as shown in Patent Document 1, the resin is polymerized to cause a decrease in solubility and fluidity, and as shown in Patent Document 2, it causes a decrease in gloss. Further, as shown in Patent Document 3 In addition, since the varnish has a high viscosity and is difficult to stably produce, a method for lowering the tack due to the extreme polymerization of the rosin-modified phenolic resin has not been generally used.

  Even today, rosin-modified phenolic resins used as varnishes for offset printing inks generally have weight average molecular weights in the range of 10,000 to 400,000, and the resin ratio can be greatly reduced at molecular weights in this range. It is not possible to provide an effect of greatly reducing the tack value during high-speed printing.

  In addition, studies have been made to reduce tack by reducing the solubility of resins used in varnishes for offset printing inks. However, this method alone does not provide a sufficient tack value reduction effect, and further promotes solvent detachment on the printing press, causing troubles such as significant change in ink over time.

  Furthermore, although the method of using vegetable oil for the production of offset ink is described in Non-Patent Document 1, the solubility with a varnish becomes an index for solving the problem of paper peeling as in the present invention. Neither is it disclosed in other patent documents and non-patent documents.

Similarly, a method of using a regenerated vegetable oil, which is a vegetable oil, for producing an ink is described in Patent Document 4 or Patent Document 5, but as in Non-Patent Document 1, as in the present invention. No mention is made of other patent documents and non-patent documents that the solubility with the varnish serves as an index for solving the problem of paper peeling.
JP 2002-322411 A JP 2002-269552 A JP 2001-106754 A JP 2000-256602 A JP 2000-156603 A "Applied Technology of Functional Inks, Chapter 28" January 27, 2003, Popular Edition, First Print, Publisher Kentaro Shima, Publisher CMC Publishing Co., Ltd.

  It is an object of the present invention to provide a osmotic dry type offset printing ink varnish for lower paper printing and an ink using the varnish, which are excellent in solving the problem of paper peeling in recent high-speed printing.

  As a result of intensive studies by the present inventors, the molecular weight of the rosin-modified phenolic resin in the varnish has a high molecular weight that has not been conventionally used as a varnish for offset printing inks, that is, a high molecular weight of 700000 to 1200000, By using, as an offset printing ink composition, a varnish using a rosin-modified phenol resin having a solubility in an aliphatic hydrocarbon solvent having 15 carbon atoms at 25 ° C. that does not cause turbidity in a 10 to 35 wt% solution. In particular, the present inventors have found that it is possible to satisfy printing aptitude excellent in solving the problem of paper peeling at the time of high-speed printing, and completed the present invention.

  That is, the present invention is a varnish using a rosin-modified phenol resin having a weight average molecular weight of 700,000 to 1200,000, and the solubility of the varnish in an aliphatic hydrocarbon solvent having 15 carbon atoms at 25 ° C. is 10 to 35% by weight. It is related with the varnish for osmotic drying type offset inks characterized by these.

  The present invention also relates to the osmotic dry offset ink varnish described above, wherein the solvent used in the varnish described above is composed only of vegetable oil.

  Furthermore, the present invention relates to the above osmotic dry offset ink varnish, wherein the solvent used in the above varnish contains a regenerated vegetable oil.

  The present invention also relates to a osmotic drying type offset ink comprising 20% by weight or more of the osmotic drying type offset ink varnish described above.

  The molecular weight of the rosin-modified phenolic resin in the varnish of the present invention has a high molecular weight of 700000 to 1200000, and the solubility of the varnish in an aliphatic hydrocarbon solvent having 15 carbon atoms at 25 ° C. is 10 to 35% by weight. A varnish using a rosin-modified phenolic resin that does not cause turbidity in the above solution and an ink using the varnish are excellent in solving the problem of paper peeling, which is likely to occur in lower paper printing particularly during high-speed printing.

  The present invention provides a penetrating dry offset printing ink varnish for lower paper printing and an ink using the varnish, which is excellent in solving the problem of paper peeling in recent high-speed printing.

  In the present invention, the weight average molecular weight of the rosin-modified phenolic resin used in the varnish is 700,000 to 12,100,000, more preferably 800,000 to 1,000,000. If the weight average molecular weight of the resin is less than 700,000, the effect of lowering the tack during high-speed printing cannot be sufficiently obtained. On the other hand, if it is more than 1200000, the elasticity becomes too strong, resulting in an excessive decrease in ink fluidity. It becomes.

  Gloss reduction due to polymerization of resin used for varnish is not a problem in offset printing for low-grade paper because low-grade paper itself is not smooth and gloss is not strongly demanded as paper quality. .

The solubility of the varnish containing the rosin-modified phenol resin in the present invention is such that the varnish is dissolved by adding an aliphatic hydrocarbon solvent having 15 carbon atoms to the varnish at room temperature of 25 ° C., and the solution becomes cloudy. It is expressed as the amount of varnish (wt%) in the solution. That is, the solubility of the varnish is expressed by the formula (1).
Formula (1)

(Chemical formula 1)
Varnish solubility (wt%)
= [Varnish amount (g)] / [varnish amount (g) + aliphatic hydrocarbon solvent (g)] × 100

In addition, the amount of varnish in the solution at the time of cloudiness becomes smaller as the varnish has better solubility. Examples of the aliphatic hydrocarbon solvent having 15 carbon atoms include “Nisseki No. 0 Solvent” manufactured by Nippon Petrochemical Co., Ltd. It is not limited to 15. In particular, a hydrocarbon solvent having an aniline point of 80 to 100 ° C. and a boiling point of 200 ° C. to 300 ° C. is suitable for the purpose of the present invention, more preferably an aniline point of 85 to 95 ° C. and a boiling point of 240 to 270. A hydrocarbon solvent at ℃ is good.

  The solubility of the rosin-modified phenolic resin contained in the varnish of the present invention in an aliphatic hydrocarbon solvent having 15 carbon atoms at 25 ° C. is preferably 10 to 35% by weight, and more preferably 15 to 30% by weight. Preferably, 20 to 30% by weight is good. If it is 10% by weight or less, the effect of lowering the tack at the time of high-speed printing is weakened, the ink setting property is further lowered, and problems such as set-off smearing and degradation of misting performance are caused. On the other hand, if it is 35% by weight or more, the ink flowability is deteriorated, and the printability is deteriorated such as the promotion of solvent removal on the printing press.

  Furthermore, regarding the decrease in solubility accompanying the polymerization of the resin in the varnish and the decrease in fluidity associated therewith, if the solubility in the varnish is within the range defined in claim 1, an excessive decrease in fluidity does not occur. Absent.

  The vegetable oil used to obtain the varnish for osmotic drying type offset printing ink of the present invention is a soybean oil, linseed oil, tung oil, tall oil, cottonseed oil, safflower oil, dehydrated castor oil, as a drying oil or semi-drying oil, Examples thereof include canola oil, rapeseed oil, regenerated soybean oil, and polymerized linseed oil.

  The regenerated vegetable oil used in the present invention is applicable as long as it can be regenerated with the above-mentioned vegetable oils. In the present invention, the vegetable oil to be regenerated (regenerated vegetable oil) includes those recovered from the vegetable oil used for the production of tempura at restaurants, school lunches, vegetable shops, etc. However, it is not limited to these, and it is applicable if it can be regenerated with the vegetable oil after use.

  In addition, examples of the method for regenerating vegetable oil according to the present invention include methods such as filtration, precipitation by standing, and decolorization by activated clay, but the method is not particularly limited and is applicable.

  As the solvent used for obtaining the varnish for the osmotic drying type offset printing ink of the present invention, an n-paraffin solvent, an isoparaffin solvent, a naphthenic solvent, an aroma, which are generally used as an offset printing ink solvent, are used. Examples include group solvents, petroleum solvents such as α-olefin, light oil, spindle oil, machine oil, cylinder oil, turpentine oil, and mineral split.

Regarding the preparation of the solubility of the varnish for osmotic drying type offset printing ink of the present invention, the solubility at 25 ° C. in an aliphatic hydrocarbon solvent having 15 carbon atoms is 10 to 35% by weight, more preferably 15 to 30% by weight. %, And 20 to 30% by weight of the solution is prepared so as not to cause turbidity. At this time, either one of the oil component and the solvent component may be used, or both may be used in combination.
Further, the osmotic dry offset ink produced in the present invention may contain the varnish for osmotic dry offset ink of the present invention in an amount of 20% by weight or more, more preferably 30% by weight or more. good. Although the osmotic drying type offset varnish of the present invention may be used alone in the ink, if the content in the ink is less than 20% by weight, the effect of suppressing paper peeling during high-speed printing is weakened. Furthermore, a varnish using a rosin-modified phenol resin having a molecular weight of 10,000 to 400,000, which is generally used, can be used in combination as long as the performance does not deteriorate.

  In the varnish for osmotic drying type offset printing ink of the present invention, a resin other than the rosin-modified phenol resin can be used in combination as long as the performance does not deteriorate. Examples of such resin components include various alkyd resins, petroleum resins, rosin ester resins, polyester resins, gilsonite, and modified products thereof.

  Examples of the gelling agent used for obtaining the varnish of the present invention include aluminum alcoholates and aluminum chelate compounds. Since there is a limit amount in which the gelation reaction proceeds sufficiently for each rosin-modified phenolic resin, it is preferable to set an appropriate value for each.

  With the increase in the viscosity of the resin, problems such as the difficulty of stable production due to the increased viscosity of the varnish and the inconvenience of varnish production such as insoluble matter are likely to occur. Can be solved by lowering the viscosity of the varnish itself.

Hereinafter, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited to the following examples.
[Examples of varnish production]
Rosin-modified phenolic resin A (weight average molecular weight 980000) and rosin-modified phenolic resin B (weight average molecular weight 1050000) as binder resins. Rosin-modified phenol resin C (weight average molecular weight 70000). Rosin-modified phenol resin D (weight average molecular weight 390000). Rosin-modified phenol resin E (weight average molecular weight 200000). AF Solvent 5 (Shin Nippon Petrochemical Co., Ltd., Aroma Free Ink Solvent) as a solvent, unused (virgin) soybean oil and regenerated vegetable oil (regenerated soybean oil) prepared as follows, and aluminum chelate (as a cross-linking agent) Aluminum diisoproxyd monoethyl acetate) was used.

  Recycled vegetable oil is filtered from waste cooking oil collected from a beet shop that uses soybean oil, left to stand overnight, then the supernatant is taken, decolorized with activated clay, and deacidified and regenerated with sodium hydroxide, Produced.

  The materials were heated and reacted at 190 ° C. for 1 hour in accordance with the formulation (wt%) shown in Table 1 to obtain gel varnishes 1-7.

〔インキ製造例〕
前記ゲルワニス１〜7と共に、表２の配合（重量％）に従い、顔料としてC.I. Pigment
Yellow（東洋インキ製造（株）製ＬＩＯＮＯＬ YELLOW １２４3―ｐ―）、及び体質
顔料としてハクエンカTDD（白石工業株式会社製）を使用し、３本ロールを用いて定法
に従い表２記載の実施例インキ１，２，３比較例インキ４，５，６を得た。

[Examples of ink production]
CI Pigment as a pigment according to the composition (wt%) in Table 2 together with the gel varnishes 1-7
Example inks listed in Table 2 according to a conventional method using Yellow (LIONOL YELLOW 1243-p-) manufactured by Toyo Ink Manufacturing Co., Ltd. 2, 3 Comparative inks 4, 5, 6 were obtained.

  Table 3 shows the results of evaluation of the ink characteristics of Example Inks 1, 2, 3 Comparative Example Inks 4, 5, 6 in the following points.

  (1) Tack value: The tack value at 400 rpm and 1200 rpm is measured with an incometer, and the lower the value at 1200 rpm, the less the paper peelability at high speed printing.

  (2) Static flow: The length of ink flowing on an inclined plate inclined at 60 ° for 10 minutes. The higher the value, the better the fluidity.

  It can be seen that the inks of Examples 1 to 3 according to the present invention are less likely to peel off during high-speed printing than the inks of Comparative Examples 4 to 6, and maintain fluidity.

Claims (4)

  A varnish using a rosin-modified phenolic resin having a weight average molecular weight of 700,000 to 1200,000, wherein the varnish has a solubility at 25 ° C. in an aliphatic hydrocarbon solvent having 15 carbon atoms of 10 to 35% by weight. Osmosis drying type varnish for offset ink.   The solvent used for the varnish of Claim 1 is comprised only by vegetable oil, The varnish for osmotic drying type offset inks of Claim 1 characterized by the above-mentioned.   The solvent used for the varnish according to claim 1 or 2 contains a regenerated vegetable oil. The varnish for osmotic drying type offset ink according to claim 1.   A osmotic drying type offset ink comprising 20% by weight or more of the varnish for the osmotic drying type offset ink according to any one of claims 1 to 3.