JP2003130786A - Method for evaluating particles in printing ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple method for inspecting and evaluating coarse particles in a printing ink with less human measurement errors at any stage of manufacturing processes of the printing ink. SOLUTION: The printing ink of a sample 1 is placed at a tip of a lower film made of a heat-sealable resin as a lower welding member 2 in a width of approximately 70-80% of the width of the film in such a way as not to extend beyond either side of the film, and an upper film of an upper welding member 3 is placed matching the lower film. By winding the films of the upper and lower welding members 2 and 3 between upper and lower heat rolls 5 and 6 previously set at an appropriate temperature and a speed, the ink is uniformly and thinly spread to create an evaluation sample 9. The presence or absence of particles 10 in the evaluation sample 9 is confirmed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating particles in a printing ink, and more particularly to an evaluation method capable of evaluating not only a manufacturing process but also a finished ink.

[0002]

2. Description of the Related Art In the production of printing ink, a pigment is dispersed in a vehicle consisting of a varnish, an auxiliary agent, a solvent and a resin to prepare a base ink having a high pigment concentration, which is diluted to obtain a final ink. Pigments, varnishes,
Stir the solvent etc., knead it with a bead mill or roll mill, and adjust it with an auxiliary agent, etc., and add varnish to the wet cake or slurry pigment, and use a kneader device to change from the aqueous phase to the oil phase. Flush and dehydrate, then
It may be finished by adjusting with varnish, solvent, additives, etc.

If pigments, varnishes, resins, and other aggregates having a large particle size are present in the base ink and the final ink, the quality stability such as the density, gloss and transparency of the printing ink and the printability are adversely affected. For example, in the kneading roll part of the printing machine, sufficient kneading cannot be performed, thin ink cannot be transferred to the plate surface, and it is not possible to reproduce a fine image image. I have a problem.

The causes of the aggregates having a large particle size are considered to be insufficient kneading in the kneading process using a roll mill or the like, and mechanical adjustment of the kneading machine being poor. In addition, in the flash production method, flash formation is incomplete, the wet cake may not be sufficiently deflocculated, and unflash may remain.

As a measurement of the particle size, a grindometer is generally used for the sake of simplicity. This grindometer is, in principle, the same as the crush gauge specified in JIS K5400 (Paint General Test Method). This crush gauge is used for examining the distribution of various crush particles up to 100 μm diameter in paint. In contrast to the method, the evaluation method of the degree of kneading with a grind meter is JIS K570.
1 (1980), an inclined groove of 0 to 25 μm is provided on the surface of the metal frame,
The diameter of a particle is estimated from the beginning of the appearance of grains or the appearance of streaks by looking at the scale indicating the depth engraved on the groove side surface. Use for this test

However, in the case of a high-concentration base ink containing a large amount of pigment, it is difficult to adhere to the slanted groove of the metal of the grindometer, and it is difficult to scrape it uniformly with a scraper, which makes accurate measurement difficult. If the sample contains a large amount of coarse particles or a mixture of gel-like lumps, the ink in the slanted groove will be scraped off cleanly, and it will be mistakenly judged that there is no particle called an off-gauge. It was sometimes lost.

In particular, yellow or light color inks, white or translucent inks, and the ones in which calcium carbonate, sedimentary barium sulfate and the like, which are the constitutions, are dispersed in kneaded meat, the particles may not be conspicuous. There were also problems that evaluation differences tended to occur due to differences in personnel, and measurement errors were prone to occur.

Further, in the case of a printing ink containing a high concentration of pigment and a large amount of coarse particles, there is a method of measuring and evaluating by diluting the base ink with a varnish or light oil so that it can be easily inspected by a grindometer. However, coarse particles are crushed during the diluting step, and the number of coarse particles themselves is diluted, so that the true state of the particles in the base ink becomes unclear, and the evaluation generally tends to be unsatisfactory.

There is also a residual method in which a sample is mainly diluted with toluene, filtered, and the residue on the filter paper is visually evaluated, but coarse particles containing agglomerates are dissolved by the solvent, and the particles are not removed on the filter paper. Since there is no residual residue and correct evaluation may not be possible, there has been a demand for a method in which the particle size does not change during the measurement and inspection steps and the ink can be inspected in its original state.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and the problem is that it can be used at any stage of the manufacturing process of printing ink and is simple and artificial. An object of the present invention is to provide a method for inspecting and evaluating particles in printing ink with little error.

[0011]

In order to solve the above-mentioned problems, the inventors of the present invention have made diligent studies, and as a result, the printing ink in the middle of manufacturing or finished product is placed on a thin member having flatness and smoothness. The present invention has been completed by finding another evaluation method by which another member is superposed on this and the viscous printing ink can be spread thinly by pressing this member and the presence of particles in the ink can be easily inspected. Came to.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the method for evaluating ink in the present invention will be described in detail with reference to FIGS. 1 and 2, but the present invention is not limited to these examples.

FIG. 1 is a diagram showing an embodiment of a method for preparing an evaluation sample according to the present invention. 1 is a sample, 1a is a thinly stretched sample, 2 is a lower crimping member, 3 is an upper crimping member, 4 is a Laminator, 5 is an upper heat roll, 6 is a lower heat roll, 7 is a speed setting unit, 8 is a temperature setting unit, 9 is an evaluation sample prepared, and 10 is coarse particles in the evaluation sample. FIG. 2 is a diagram showing another embodiment. In each figure, the same reference numerals are used for the same structures and functions.

In FIG. 1, at the tip of a resinous lower film which can be heat-sealed as the lower pressure-bonding member 2, the printing ink of Sample 1 is about 70% to 80% of the width of the film so as not to protrude from both sides of the film. Then, the upper film, which is the upper pressure-bonding member 3, is placed on the lower film so as to cover it. At least one of the members to be pressure-bonded is preferably transparent for the evaluation of particles.

The amount of ink placed on the film as a sample is
In the case of the film width A4 vertical size, 0.2 g to 3 g is suitable, and in the case of lithographic ink, if it is 0.5 g to 2 g, a good evaluation sample thinly extended to the rear end portion can be obtained.

The ink may be placed anywhere as long as the laminated portion can be secured in the surroundings, but in order to obtain a sufficiently large evaluation sample, it is preferable to place it on the leading end side of the film fed to the heat roll.

The power of the laminator 4 is turned on in advance, and the upper and lower heat rolls 5 are adjusted according to the material of the film and the liquid property of the sample.
The peripheral speed and the temperature of 6 are set by the speed setting unit 7 and the temperature setting unit 8.

When the viscosity of the ink is high, the temperature of the heat roll is adjusted so that the ink is spread uniformly. The temperature of the heat roll depends on the material and thickness of the film, but is generally about 90 ° C to 150 ° C.

With respect to the film thickness of the ink to be laminated, it is possible to obtain a sample which can be visually evaluated easily by adjusting the peripheral speed of the heat roll, depending on the type and liquid properties of the ink. Roll speed is 0.1m / min ~
When the ink has a viscosity of about 2.5 m / min and the viscosity is higher, the roll temperature is higher and the roll speed is slower.

When the pressure-bonding members 2 and 3 differ in material and thickness, a well-known mechanism such as an eccentric mechanism and a vertical displacement adjusting mechanism is provided in the bearing portion of the rotating shaft of the upper heat roll 5 or the lower heat roll 6. By adjusting the gap between the heat rolls and setting the pressure appropriately, it is possible to obtain an evaluation sample that matches the liquid properties of the sample.

With the above setting, the films of the upper and lower pressure bonding members 2 and 3 are wound between the rotating heat rolls. The ink, which is a viscous material, is spread uniformly and thinly, and the ink-free portion is sealed, by an appropriate temperature, roll pressure, and roll speed that match the properties such as viscosity of the printing ink.

The heat-sealing machine used in the evaluation method of the present invention is not special, and equipment used for office work is sufficient. Here, the upper pressure-bonding member 3 may be a flexible member having a heat-melting adhesive layer formed on one surface thereof and having a certain degree of transparency. It does not have to be flexible.

In the case of laminating, polyethylene is preferably used as a film having a heat-sealing property, but a heat-meltable adhesive layer is formed on one surface of the film.
It should have a thickness convenient for storing the evaluation sample.

When a film is used, the upper and lower films 2 and 3 may be used, but whether one end is sealed beforehand,
If you use a butt or bag-shaped one,
Since it is not necessary to overlap the leading ends of the films, the work of preparing an evaluation sample is simplified, which is more preferable.

It is not always necessary that the heat-melting adhesive layer is formed, and an ordinary pressure-sensitive adhesive film or a film which produces pressure-sensitive adhesiveness may be used. Even if it is not heated by passing it between the upper and lower pressure rolls, the thinly stretched evaluation sample 9 can be prepared for the sample 1 having a relatively small viscosity.

FIG. 2 shows another embodiment, in which the sample 1 is placed near the central portion of the thin plate-like lower pressure-bonding member 2 and the upper pressure-bonding member 3 is stacked to use known pneumatic, electrical and mechanical means. If a pressing member (not shown) engaged with the pressing means is pressed at an appropriate pressure, the sample is thinly extended in the outer peripheral direction, so that an evaluation sample can be prepared.

It is sufficient for the pressure-bonding members 2 and 3 to have such strength that they are not deformed by pressing force and at least one of them has transparency. For example, glass or a transparent resin plate having a smooth surface may be used. Further, if a heating function is provided in the portion on which the lower pressure-bonding member 2 is placed, the sample 1 can be reasonably thinly stretched even when the sample 1 has a high viscosity, so that the evaluation sample 9 that is easy to evaluate can be obtained.

Since the ink of Sample 1 is a viscous material,
Since the upper and lower crimping members 2 and 3 do not come into close contact with each other after being crimped, it is not always necessary to have an adhesive layer on this surface, but in consideration of the form of storage and storage of the evaluation sample 9 for a long period of time, It is desirable to make an evaluation sample by pressure bonding with an adhesive.

The evaluation sample 9 prepared by the method of FIG. 1 or 2 is placed on a light table and extended.
Whether or not there are coarse particles 10 in a is visually checked, or the particle size is measured using a loupe or the like, and evaluated according to a standard. Since it is thinly stretched, coarse particles and agglomerates in the viscous material can be discriminated even for light-colored or dark-colored ink.

At this time, by using the lower pressure-bonding member 2 having a color that can be easily identified by the color of the sample 1, it is possible to obtain the evaluation sample 9 with few inspection mistakes by the measurer. For example, white, light color,
If you use a dark-colored lower pressure-bonding member such as black for the yellowish sample 1, and conversely, use a white or milky white-type lower pressure-bonding member for a sample with high concealment such as black, red, indigo, etc. Coarse particles of can be easily found.

[0031]

EXAMPLE A heating roll press bonding method (laminating type) as one embodiment of the present invention as shown in FIG. 1 will be described below.

(Example) The laminator used in the test was manufactured by Fuji Plastics Co., Ltd., the model was LAMIPACKER LPD3204, and the viscosity was measured with a B-type viscometer (at 25 ° C.). The ink of Sample 1 is manufactured by Dainippon Chemical Industry Co., Ltd.
1 is N / Z Naturalis MKHS (base for yellow AF),
No. 2 is N / Z Naturalis CN-2 (yellow base),
No. 3 is 6B-GQX.

Table 1 shows the results of visual evaluation of each evaluation sample 9 prepared after the thermocompression bonding on a light table.

[0034]

[Table 1]

(Comparative Example) Sample No. 1-No. When 3 was measured with a grindometer, it was difficult to confirm the particles due to the influence of color, and the particles were scraped off, and the measurement could not be performed.

[0036]

EFFECTS OF THE INVENTION According to the present invention, a particle size of 25 μm to 3000 μm or even a particle size of 25 μm to 3000 μm or more can be easily measured without being affected by the composition and color of the ink, and the measurement range of the conventional grindometer can be used. Is 100μ
When used in combination with the particle evaluation method of m or less, a wider range of printing inks can be evaluated accurately.

The sample ink may be any kind of lithographic ink, gravure ink, flexo ink, etc. for printing, but in the case of laminating by heating with a heat roll and pressure bonding, the solvent content is not included so much. Preferred are lithographic printing inks for newspapers, rotary presses, and sheet-feds, which have a relatively high flash point and are thin and easy to spread.

In the evaluation method according to the present invention, the viscosity range is not particularly limited by adjusting the heating temperature of the sample, but a high-pigment, high-viscosity printing ink containing a flushed base ink, a adjusting process, It is especially effective for evaluation.

Since this evaluation method by measurement / inspection can be easily applied to each stage of the in-process product in the intermediate stage of production, if the evaluation result can be grasped in the intermediate stage of production, for example, the conditions for kneading meat can be changed in the subsequent steps. It is also possible to improve the yield of the final product by dealing with. That is, it is possible to inspect the state of particles in the ink in each process to determine the quality of the ink, and if there is a quality defect, quickly deal with the defective process and suppress the product defect to the minimum limit.

The evaluation sample prepared from a laminated film or the like does not cause deterioration of coarse particles and can be stored as it is as a raw ink without treatment such as solvent dilution. Can be stored easily, and because the sample does not change over time,
It is also an excellent evaluation method for preservation of quality records and quality control.

[Brief description of drawings]

FIG. 1 is a schematic view of an evaluation sample preparation showing an embodiment of the present invention.

FIG. 2 is a schematic diagram of evaluation sample preparation showing another embodiment of the present invention.

[Explanation of symbols]

1 sample 2 Lower crimp member 3 Upper crimp member 4 Laminator 5 Upper heat roll 6 Lower heat roll 7 Speed setting section 8 Temperature setting section 9 Evaluation sample 10 coarse particles

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshiharu Otoshi             3-7-4 Kamimine, Saitama City, Saitama Prefecture F term (reference) 2G052 AA00 AD29 AD37 DA07 FD06                       FD13 GA11 JA04 JA09 JA13                       JA16

Claims (4)

[Claims] 1. Two planar crimping members, wherein at least one of the crimping members is transparent, and the printing ink placed between the crimping members is crimped,
A method for evaluating particles in a printing ink, wherein particles in the printing ink are evaluated using an evaluation sample obtained by thinly spreading the printing ink. 2. The method for evaluating particles in a printing ink according to claim 1, wherein at least one of the pressure-bonding members has flexibility and an adhesive layer is formed on one surface. 3. The method for evaluating particles in printing ink according to claim 1, wherein the adhesive layer is formed of a heat-meltable adhesive. 4. The method for evaluating particles in printing ink according to claim 1, wherein the pressure bonding of the pressure bonding member is a laminating process using a heating roll.