JPH079558A - Manufacture of printing plate material - Google Patents

Abstract

PURPOSE:To prevent mixing of the air at the time of laminating photosensitive resin composition by placing a center of a rotary shaft of nip rolls on an extension line of an extrusion die in a discharging direction, and setting a shortest distance between a discharge port end of the die and a support on a surface of the roll to the same or less as a thickness of a resin layer of a printing plate material. CONSTITUTION:A distance (c) between a discharge port end of an extrusion die 5 and a support 6 on a surface of a roll 8a is set to the same or less as a thickness (d) of a resin layer of a sheet to be molded by nip rolls 8. For example, when a lip port 5b of the die 5 approaches the upper roll 8a, movement or resin in a reverse direction of the roll 8a is eliminated, and hence bubbles are easily engulfed. When an extension line is disposed lower than a rotary shaft of a lower roll 8a, resin from the die 5 is not adhered to the support 6 of outside of the roll 8a but dropped down. When the distance (c) is larger than the thickness (d) of the layer, flow of the resin to a reverse rotation direction of the roll 8a is eliminated thereby to obviate air mixing preventing effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for molding a printing plate material having a photosensitive resin layer, more specifically, a photosensitive resin composition containing a rubber component is passed through a nip roll and wound around the roll. When a printing plate material is laminated on a support and molded into a printing plate material, a printing plate material is obtained which is free of air entrapment between the photosensitive resin layer or the photosensitive resin layer and the support. The present invention relates to a manufacturing device.

[0002]

2. Description of the Related Art Flexographic printing plates used for printing packaging materials such as cardboard and flexible and easily deformable materials such as films must have an appropriate elastic surface. A photosensitive resin composition containing a rubber component is used as a molding material for a flexographic printing plate material. For example, Japanese Patent Laid-Open No. 1-219735 discloses a photosensitive resin composition obtained from a composition based on a hydrophobic polymer having a glass transition point of 5 ° C. or lower and a hydrophilic polymer.

To produce a printing plate material using the above resin composition, a solution of the resin composition is prepared with water and / or an organic solvent, the solvent is evaporated, and the remaining solvent is 1% by weight. After concentrating as follows, it is discharged from an extruder into a sheet, and when this sheet is passed between nip rolls consisting of a pair of upper and lower rolls, the sheet is laminated on a support wound on one roll. A printing plate material is created.

And, such a printing plate material is usually
It is molded to a thickness of 0.5 mm to 10 mm and used for flexographic printing, for example, as follows.

After the support of the printing plate material is peeled off, a negative film having an image is adhered onto the photosensitive resin layer, and then a light such as a mercury lamp is irradiated for a certain period of time to expose the exposed part. After insolubilization, the resin in the non-irradiated portion is washed away with a developing solution to develop.

Here, when the photosensitive resin layer has fine air bubbles, since no resin is present in the foamed portion, no relief is formed and the printing plate material has a fatal defect.

By the way, the above-described laminate molding using an extrusion die is generally used for molding a thermoplastic resin sheet of polypropylene, polyethylene, polystyrene or the like, and the resin discharged from the die is used. As a method of improving the adhesion between the sheet and the support and preventing the inclusion of air bubbles, it is said that it is effective to make the resin discharge direction from the extrusion die the tangential direction of the nip roll as close to the roll as possible. .

However, when a printing plate material is prepared as described above using a photosensitive resin composition containing a rubber component, the viscosity of the resin composition is 5000 poise to 200 poise.
Since it is 00 poise, air is easily trapped in the resin layer or between the resin layer and the support at the time of contact with the support.

As a method for positively eliminating the trapping of air at the time of contact with such a support, for example, JP-A-5-7816 discloses a method of installing a decompression chamber in a bead coating apparatus. Proposed. This method is a method of eliminating air from the area immediately before being applied to the substrate through the decompression chamber, but it has the drawback that it is difficult to control air leakage to the decompression chamber and stable production cannot be performed. .

[0010]

DISCLOSURE OF THE INVENTION The present invention has been made in order to solve the above-mentioned drawbacks, and the purpose of the present invention is to provide air when a photosensitive resin composition is laminated on a support. Another object of the present invention is to provide an apparatus for manufacturing a printing plate material that is prevented from being mixed.

[0011]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made diligent research efforts to prevent air inclusion when laminating a photosensitive resin composition containing a rubber component on a support, which cannot be solved by the above-mentioned conventional techniques. As a result, the present invention has been completed.

That is, according to the present invention, an extrusion die for discharging a photosensitive resin composition into a sheet, a nip roll consisting of a pair of rolls for passing an extruded sheet while pressing it, and a nip roll formed by the nip roll. In a manufacturing apparatus of a printing plate material including a take-up device for taking up the printing plate material, on the extension line of the extrusion direction of the resin composition of the extrusion die, the rotation axis center of the roll of the nip roll is Whether the extrusion die is arranged so as to be substantially located, and whether the distance between the tip of the ejection port of the extrusion die and the support on the roll surface is the same as the resin layer thickness of the printing plate material. Or less, which achieves the above object.

The present invention will be described in more detail with reference to the drawings.

FIG. 1 is a schematic view showing an example of an apparatus for producing a printing plate material of the present invention. This apparatus comprises a mixing tank 1 for preparing a resin composition solution by mixing a photosensitive resin composition with water and / or an organic solvent, a pump 2 for quantitatively transferring the solution from the mixing tank 1, water and / or Concentrator 3 for evaporating almost all the organic solvent, pump 4 for quantitatively discharging the concentrated photosensitive resin composition from the concentrator 3, and extrusion for discharging the photosensitive resin composition into a sheet. The die 5, a sheet made of the photosensitive resin composition, a support 6 such as a metal or a film, and a cover film 7.
And a take-up conveyor 9 for taking up the laminated printing plate material 11.

Here, it is effective to heat the mixing tank 1 in order to make the mixing and adjustment of the resin composition uniform in a short time. Usually, the mixing tank 1 having a jacket of a heated medium is used. . A screw, a gear pump, or the like can be used as the quantitative transfer pump 2. It is effective that the concentrator 3 uses a vent-type twin-screw extruder to evaporate almost all water and / or the organic solvent, and that the vacuum pump 10 discharges steam from the vent port.

As the pump 4 for quantitatively extruding the photosensitive resin composition, a screw, a gear pump or the like can be used. The die 5 for discharging the photosensitive resin composition in a sheet form may be a T die, a fish tail die, a coat hanger die, and a sheeting die such as a die with a distribution device, which are generally used for extrusion molding. Available.

As the nip roll 8, a pair of heated metal rolls having good rotation accuracy and roll accuracy are usually used. One roll 8a of the nip rolls 8 has
A support 6 such as a metal or a film is wound.
When a printing plate material in which a support 6 such as a metal or a film and a cover film 7 are laminated on both surfaces of a resin layer made of a photosensitive resin composition, a printing plate material for the nip roll 8 is formed on the other roll 8b. , The cover film is wound.

FIG. 2 is a partial detailed view of the extrusion die 5 and the nip roll 8 showing an example of the printing plate material manufacturing apparatus of the present invention.

In FIG. 2, a pair of upper and lower rolls 8a, 8
The die 5 is disposed on the lower roll 8a side of the nip roll 8 composed of b. The positional relationship between the die 5 and the nip roll 8 is set so that the center of the rotation axis of the roll 8a therebelow is substantially located on the extension line of the die 5 in the resin discharge direction. Here, the fact that the center of the rotation axis of the roll 8a therebelow is located substantially on the extension line of the resin discharge direction of the die 5 means that the direction of resin discharge of the die 5 is The center of the rotation axis of the roll 8a may be slightly deviated from the extension line, and may change depending on the characteristics (viscosity, viscosity) of the resin, the extrusion speed of the resin, the size and rotation speed of the nip roll 8 and the distance c described later.

The discharge speed of the resin is preferably 0.1 m / min to 3 m / min, more preferably 0.24 m / min to 1.1 m / min.
The rotation speed of the nip roll 8 is 0.1 m / min.
10 m / min is preferable, and 0.18 m / min is more preferable.
It is 4.4 m / min.

The distance c between the tip of the discharge port of the extrusion die 5 and the support 6 on the surface of the roll 8a is the nip roll 8
The thickness is set to be equal to or less than the resin layer thickness d of the sheet molded in. Specifically, the distance c is preferably in the range of the resin layer thickness d to the resin layer thickness d minus 0.2 mm.

The photosensitive resin composition supplied to the die 5 is
Roll 8 from die lip opening 5b through the resin passage 5a
It is discharged toward the center of the a-axis. The resin discharged in the axial direction of the roll 8a flows on the support 6 as follows. That is, most of the photosensitive resin composition flows in the rotation direction of the roll 8a as the support 6 moves, but some of the photosensitive resin composition moves in the opposite direction to the rotation direction of the roll 8a ( In FIG. 2, after flowing downward, the support 6
The fluid flows in the rotation direction of the roll 8a.

When the center of the rotation axis of the roll 8a is substantially deviated from the extension line of the resin discharging direction from the extrusion die 5,
For example, the lip port 5b of the extrusion die 5 has the upper roll 8
When approaching a, the resin does not move in the opposite direction of the roll 8a, so that it is easy to involve foaming. When the extension line of the extrusion die 5 in the resin discharge direction is located below the center of the rotation axis of the lower roll 8a, the resin extruded from the lip port 5b of the die 5 is supported outside the roll 8a. There is a risk that it may fall downward without adhering to the body 6 or adhere to the lower part of the lip opening 5b.

When the distance c is larger than the resin layer thickness d of the sheet molded by the nip roll 8, the roll 8a
Almost no resin flows in the reverse rotation direction, and it is not effective in preventing air from entering. If the distance c is too smaller than the resin layer thickness d, the flow of the resin in the opposite direction becomes large, and the discharged resin may adhere to the lower portion of the die lip.

FIG. 3 is a partial detailed view of the die 5 and the nip roll 8 showing an example of an apparatus for producing a printing plate material according to the present invention.

In FIG. 3, the distance c between the tip of the extrusion die discharge port and the support 6 on the surface of the roll 8a is 0.5 m from the thickness d of the resin layer of the sheet molded by the nip roll 8.
It is set large.

With respect to the resin discharged toward the center of the rotation axis of the roll 8a, all the photosensitive resin composition flows on the support 6 in the rotation direction of the roll 8a. As a result, the contact position of the resin composition with respect to the support 6 becomes unstable at the contact portion e between the support 6 on the roll 8a and the discharged photosensitive resin composition, and the adhesiveness with the support 6 is also increased. It causes variations and causes air to be trapped.

[0028]

The extrusion die is arranged such that the center of the rotation axis of the roll is substantially located on an extension line of the extrusion die in the direction of ejection of the resin composition, and the tip of the ejection port of the extrusion die and the support are provided. By setting the distance to be equal to or less than the resin layer thickness of the printing plate material, while most of the resin discharged from the extrusion die flows in the roll rotation direction,
A part of the discharged resin also flows in the direction opposite to the rotation, and the flow of the resin in the opposite direction prevents air from being mixed into the resin layer or between the resin layer and the support.

That is, since the contact angle of a part of the resin flowing in the direction opposite to the rotation direction of the roll with respect to the support is smaller than that in the conventional case, the inclusion of air is prevented.

The same effect as described above can be obtained by making the distance larger than the thickness of the resin layer of the sheet and slowing down the rotation speed of the nip roll, but in this case, the resin is accumulated in the nip roll, which is preferable. Absent.

[0031]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited thereto. In the following examples, “part” means “part by weight”.

(Example 1) Hexamethylene diisocyanate 21.8 parts, dimethylol propionic acid 15.4
Part, polytetramethylene glycol 7.6 parts, and di-n-butyltin diuranate 1 part dissolved in 300 parts tetrahydrofuran were placed in a tank equipped with a stirrer and the tank was heated to 65 ° C. while continuing stirring. The reaction continued for an hour.

In a separate container, 55.3 parts of acrylonitrile-butadiene oligomer containing terminal amino groups was dissolved in 100 parts of methyl ethyl ketone to prepare a solution. This solution was added to the above tank at room temperature with stirring. The obtained polymer solution was dried under reduced pressure to remove tetrahydrofuran and methyl ethyl ketone, and the average molecular weight was 21,
000 polymers were obtained. Next, a solution prepared by dissolving 4.8 parts of lithium hydroxide in 100 parts of methyl alcohol was added to a solution prepared by dissolving 100 parts of the polymer in 100 parts of methyl ethyl ketone at room temperature with stirring, and further stirred for 30 minutes. A hydrophilic polymer was obtained.

Next, 5 parts of the hydrophilic polymer, 20 parts of chlorinated polyethylene as a hydrophobic polymer, 5 parts of styrene-butadiene rubber, 0.25 part of hydroquinone monomethyl ether, 33 parts of a mixed solvent of water, methyl ethyl ketone and tetrahydrofuran are mixed. A photosensitive resin composition solution was obtained.

Next, using the apparatus shown in FIG. 1, the composition solution was transferred to the concentrator 3 by the gear pump 2 and the solvent was evaporated from the vent section at a screw rotation speed of 100 rpm and a vacuum degree of 10 Torr. The photosensitive resin composition was concentrated to a concentration of 98% by weight.

On the other hand, a 0.16 mm polyester film support 6 and a 0.1 mm polyester film cover film 7 are provided as a pair of metal rolls 8a, 8 respectively.
The total thickness of the printing plate material after being sent to b is 2.9.
The gap c between the pair of metal rolls is 2.9 so that the distance becomes 4 mm.
4 mm, the die discharge port tip and the support 6 on the roll surface
The distance between and was 2.71 mm.

Next, the die 5 heated to 100 ° C. was used to discharge it using a gear pump, and was passed between the pair of heated metal rolls 8a and 8b to form the printing plate material 11.

The molded printing plate material was visually inspected for bubbles on a commercially available light table, and no bubbles were observed.

(Comparative Example) A pair of photosensitive resin compositions prepared in the same manner as in Example 1 was used in the same manner as in Example 1 so that the total thickness of the printing plate material after molding was 2.94 mm. By adjusting the gap between the metal rolls 8a and 8b, the distance between the tip of the die discharge port and the support 6 on the roll surface is 2.51 mm,
The printing plate material 11 was molded by discharging the photosensitive resin composition while changing the distance to 2.61 mm and 2.81 mm.

With respect to the molded printing plate material, bubbles were visually inspected on a commercially available light table. As a result, Table 1 was obtained.

Support 6 on the tip of the die discharge port and on the roll surface
The size of the bubbles observed at a distance of 2.81 mm and 2.91 mm was in the range of 0.15 mm to 0.8 mm in diameter.

[0042]

[Table 1]

[0043]

According to the apparatus of the present invention, it is possible to prevent air bubbles, which is a fatal defect as a printing plate material, from entering, and to obtain a printing plate material with stable quality.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of the device of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of the device shown in FIG.

FIG. 3 is a partially enlarged view showing an example of a relationship between a nip roll and a die in a device not according to the present invention.

[Explanation of Codes] 1 Mixing tank 2 Pump 3 Concentrator 4 Pump 5 Die 6 Support 7 Cover film 8 Nip roll 9 Take-up conveyor 10 Vacuum pump

Claims (1)

[Claims] 1. An extrusion die for discharging a photosensitive resin composition into a sheet, allowing the extruded sheet to pass while being pressed, and laminating the sheet on a support wound on one roll. In a printing plate material manufacturing apparatus comprising a nip roll for molding into a printing plate material, and a take-up device for picking up the molded printing plate material, a discharge direction of the resin composition of the extrusion die The extrusion die is arranged such that the center of the rotation axis of the roll of the nip roll is substantially located on the extension line of, and the tip of the ejection port of the extrusion die and the support on the roll surface. A printing plate material manufacturing apparatus, wherein the shortest distance from the body is set to be equal to or less than the resin layer thickness of the printing plate material.