JP5116622B2 - Method for producing cylindrical printing original plate for laser engraving - Google Patents

Description

  The present invention relates to a method for producing a cylindrical printing original plate for laser engraving.

In recent years, when resin letterpress such as flexographic printing, dry offset printing, and letterpress printing is manufactured, or when surface processing such as embossing is performed, the resin layer surface irradiated with laser light is irradiated. A laser engraving method for forming a concavo-convex pattern on the surface has been used as a result of removal of.
Materials applied to the laser engraving method include vulcanized rubber, a cured photosensitive resin obtained by photocuring a photosensitive resin composition, and a thermosetting resin obtained by thermosetting a thermosetting resin composition. A cured product is used. In particular, in recent years, from the viewpoint of shortening the processing time, a technique for laser engraving a photosensitive resin cured product obtained by photocuring a photosensitive resin composition has increased.

  In Patent Document 1, a sheet-like photosensitive resin composition made of a thermoplastic elastomer is wound on a hollow cylindrical support, the ends are welded, and an adhesive is used to sheet-photosensitive the hollow cylindrical support. A method for producing a cylindrical printing original plate by bonding a resin composition is described.

Japanese Patent No. 2846954

However, since the method described in Patent Document 1 requires a considerable time until the adhesive is cured, it is a problem that the dimensional accuracy such as roundness and thickness distribution of the cylindrical printing original plate is lowered. Yes.
In the prior art, there is no method for manufacturing a cylindrical printing original plate with high dimensional accuracy with high productivity.

  The problem to be solved by the present invention is to provide a method capable of producing a cylindrical printing original plate with high dimensional accuracy and high productivity.

  As a result of diligent studies to solve the above problems, the present inventors have used a specific sheet-shaped resin and a heat-shrinkable tube having laser light absorption as a method for producing a cylindrical printing original plate for laser engraving. 1) a step of coating a cylindrical support (a) with a heat-shrinkable tube having laser light absorption; (2) a step of heating and shrinking the heat-shrinkable tube; and (3) a shrunk tube. A step of winding a sheet-like resin on a cylinder, (4) a step of bringing the sheet-like resin into contact with the contracted tube surface, and (5) irradiating the contacted portion with laser light (α). The present invention has been completed by finding that the above-mentioned problems can be solved by using a production method including a step of adhering to each other.

The present invention is as follows.
1.
A method for producing a cylindrical printing original for laser engraving,
(1) A step of coating the cylindrical support (a) with a heat-shrinkable tube having laser light absorption;
(2) heating and shrinking the heat-shrinkable tube;
(3) coating the sheet-like resin on the contracted tube;
(4) contacting the sheet-like resin with the contracted tube surface;
(5) irradiating the contacted part with laser light (α) and adhering it,
A method for producing a cylindrical printing original plate for laser engraving, wherein the sheet-like resin comprises at least one material selected from the group consisting of a thermoplastic resin, a photosensitive resin composition, and a thermosetting resin composition.
2.
The step (5) is a step of irradiating the interface where the sheet-shaped resin and the contracted tube are in contact with each other while focusing the laser beam (α). The manufacturing method as described in.
3.
1. The light transmittance of the sheet-like resin is 50% or more and 100% or less at the oscillation wavelength of the laser beam (α). Or 2. The manufacturing method as described in.
4).
1. The oscillation wavelength of the laser beam (α) is 700 nm or more and 3 μm or less. To 3. The manufacturing method of any one of these.
5.
The laser beam (α) is
A continuous wave laser, or a pulsed laser whose laser pulse has a half-value duration of 1 nanosecond to 50 milliseconds,
1. The average output of the laser beam (α) is 0.01 W or more and 200 W or less. To 4. The manufacturing method of any one of these.
6).
1. The beam diameter at the focal point of the laser beam (α) is 1 μm or more and 5 mm or less. To 5. The manufacturing method of any one of these.
7).
1. The light transmittance of the heat-shrinkable tube is 10% or less at the oscillation wavelength of the laser beam (α) used. To 6. The manufacturing method of any one of these.
8).
The heat shrinkable tube comprises a dye or pigment that absorbs near infrared radiation; To 7. The manufacturing method of any one of these.
9.
1. The thickness of the heat-shrinkable tube is 10 μm or more and 500 μm or less. To 8. The manufacturing method of any one of these.
10.
1. The centerline average surface roughness Ra of the heat-shrinkable tube is 0.5 μm or less. To 9. The manufacturing method of any one of these.
11.
The photosensitive resin composition or the thermosetting resin composition is polyamide, polyimide, polyurethane, polyester, polycarbonate, polyether polyol, polyvinyl alcohol, vinyl alcohol-vinyl acetate copolymer, styrene-butadiene copolymer, and styrene. -Containing at least one resin selected from the group consisting of isoprene copolymers; To 10. The manufacturing method of any one of these.
12
The cylindrical support (a) includes a fiber reinforced plastic, and the fiber reinforced plastic includes glass fiber, polyamide fiber, polyimide fiber, polyester fiber, polyurethane fiber, cellulose fiber, carbon fiber, metal fiber, and ceramic fiber. Containing at least one fiber selected from the group; To 11. The manufacturing method of any one of these.
13.
The cylindrical support (a) is a hollow cylindrical support, and the thickness of the hollow cylindrical support is 0.2 mm or more and 2 mm or less. To 12. The manufacturing method of any one of these.
14
A photosensitive resin composition or a thermosetting resin composition having a thickness of 50 μm or more and 5 mm or less on a sheet-like support made of a thermoplastic resin having a thickness of 10 μm or more and 500 μm or less. Or a laminate in which cured products thereof are laminated; To 13. The manufacturing method of any one of these.
15.
1. To 14. Production of a cylindrical printing plate for laser engraving, comprising the step of irradiating a laser beam (β) to form a concave pattern on the cylindrical printing original plate for laser engraving produced by the production method according to any one of the above Method.
16.
14. The cylindrical printing plate for laser engraving is a flexographic printing plate, a dry offset printing plate, or a gravure printing plate, A method for producing a cylindrical printing plate for laser engraving as described in 1.
17.
16. A dry offset printing method for printing on the surface of a cylindrical substrate using the dry offset printing plate produced by the production method described in 1.
18.
Printing with inks containing aliphatic and / or aromatic hydrocarbons, 17. The dry offset printing method described in 1.

  ADVANTAGE OF THE INVENTION According to this invention, the method of manufacturing the laser-engraving cylindrical printing original plate which forms a pattern on the surface with a laser engraving method with high thickness precision and high productivity can be provided.

  Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

[Method of manufacturing cylindrical printing original plate for laser engraving]
The method for producing the cylindrical printing original plate for laser engraving of the present embodiment is as follows:
A method for producing a cylindrical printing plate in which a sheet-like resin is bonded onto a cylindrical support (a),
(1) A step of coating the cylindrical support (a) with a heat-shrinkable tube having laser light absorption;
(2) heating and shrinking the heat-shrinkable tube;
(3) coating the sheet-like resin on the contracted tube;
(4) contacting the sheet-like resin with the contracted tube surface;
(5) irradiating the contacted part with laser light (α) and adhering it,
In the method for producing a cylindrical printing original plate for laser engraving, the sheet-like resin is made of at least one material selected from the group consisting of a thermoplastic resin, a photosensitive resin composition, and a thermosetting resin composition. .
The manufacturing method of the present embodiment is a method in which a sheet-shaped resin and a contracted tube are bonded by a laser welding method, and laser light (α) is applied to an interface portion where the sheet-shaped resin and the contracted tube are in contact with each other. By irradiating, it is possible to bond in a very short time.

[Step (1)]
In the present embodiment, as a method of coating the cylindrical support (a) in step (1) with a heat-shrinkable tube having laser light absorption, a heat-shrinkable sheet is wound around the cylindrical support (a), A method of adhering or welding the peripheral ends, a method of fitting a tube in which the peripheral ends of the heat-shrinkable sheet are bonded or welded in advance to the cylindrical support (a), and a seamless heat-shrinkable tube in a cylindrical shape Examples thereof include a method of fitting into the support (a).

"Heat-shrinkable tube"
The heat-shrinkable tube used in the present embodiment is a heat-shrinkable tube having both the property of shrinking when heated and the property of absorbing laser light (α).
Regarding the shrinkage characteristics of the heat-shrinkable tube, the heat shrinkage rate at 80 ° C. is preferably 10% or more and 50% or less. A more preferable range is 20% or more and 50% or less, and further preferably 20% or more and 40% or less.
If the thermal contraction rate is within the above range, it can be securely fixed to the cylindrical support (a), can be prevented from shifting in the circumferential direction even in the printing process, and sufficient mechanical strength can be secured. is there.

The thickness of the heat-shrinkable tube is preferably 10 μm or more and 500 μm or less. A more preferable range is 25 μm or more and 250 μm or less, and further preferably 50 μm or more and 150 μm or less.
If the thickness of the heat-shrinkable tube is within the above range, the tube can be easily formed and sufficient mechanical strength can be ensured.

Since the laser beam (α) is applied to the contact interface between the heat-shrinkable tube and the sheet-like resin, the heat-shrinkable tube needs to absorb the laser beam (α) used for welding.
The heat-shrinkable tube preferably contains a laser light absorber in order to absorb the laser light (α). Since laser light having an oscillation wavelength in the near infrared region is preferable as the laser light (α), the laser light absorber preferably contains a dye or pigment having light absorption characteristics in the near infrared region.
Preferred compounds as laser light absorbers include black pigments such as carbon black, graphite, activated carbon, carbon nanotubes, fullerenes, organic dyes and organic pigments such as phthalocyanine, azo, perinone, and anthraquinone, iron oxide, oxidation Examples thereof include metal oxides such as copper, inorganic pigments such as chromates, sulfides, silicates, carbonates, and ferrocyanides.

The light transmittance of the heat-shrinkable tube is preferably 10% or less, more preferably 1% or less, and further preferably 0.1% or less at the oscillation wavelength of the laser light (α) to be used. .
If the light transmittance of the heat-shrinkable tube is within the above range, the laser beam can be sufficiently absorbed.

  The heat-shrinkable tube may be a tube in which both ends of the film are welded or a seamless tube without a joint. In the case of forming both ends of the film by welding, the film can be produced by molding using a technique such as extrusion molding or casting, and then stretching. Moreover, a seamless tube can be produced by inflation using a circular die or a ring die.

  Examples of the material for the heat-shrinkable tube include materials such as polyolefin, polyester, polystyrene, polyamide, and polyvinyl acetate.

  The centerline average surface roughness Ra of the heat-shrinkable tube is preferably 0.5 μm or less from the viewpoint of securing the adhesive strength with the sheet-like resin laminated thereon. More preferably, it is 0.4 micrometer or less, More preferably, it is 0.2 micrometer or less.

[Cylindrical support (a)]
The cylindrical support (a) used in the present embodiment is made of a metal, rubber or plastic cylinder, and made of plastic, metal or fiber reinforced plastic from the viewpoint of molding accuracy and ease of handling. A cylindrical support such as a sleeve can be used.
The cylindrical support (a) is preferably a hollow cylindrical support made of fiber-reinforced plastic from the viewpoint of handling and mass.
The fiber reinforced plastic is a plastic containing at least one kind of fiber selected from the group consisting of glass fiber, polyamide fiber, polyimide fiber, polyester fiber, polyurethane fiber, cellulose fiber, carbon fiber, metal fiber, and ceramic fiber. Is preferred.

When the cylindrical support (a) is a hollow cylindrical support, the hollow cylindrical support is used from the viewpoints of ensuring mechanical strength that does not crack or chip, presence or absence of twisting during high-speed rotation, weight reduction, and ease of handling. The body thickness is preferably 0.2 mm or more and 2 mm or less. More preferably, they are 0.3 mm or more and 1.5 mm or less, More preferably, they are 0.4 mm or more and 1 mm or less.
If the thickness of the hollow cylindrical support is within the above range, it can be easily attached to the air cylinder, and sufficient mechanical strength can be secured without being broken or cracked.

[Step (2)]
In the present embodiment, as a method of heating and shrinking the heat-shrinkable tube in the step (2), a method of blowing hot air to the heat-shrinkable tube, a method of holding in a heated atmosphere such as an oven, a heat ray such as infrared rays And a method of contacting with a heated cylinder or flat plate.

  By contracting the heat-shrinkable tube, the contracted tube can be held on the cylindrical support (a) by the contraction force.

[Step (3)]
In the present embodiment, the method of coating the sheet-shaped resin on the contracted tube in the step (3) is not particularly limited, and a method of winding the sheet-shaped resin on the contracted tube can be exemplified. . As a method of winding the sheet-shaped resin, it is preferable to wind the sheet-shaped resin in a cylindrical shape, and it may be wound around the entire circumference of the cylindrical support (a), or may be wound around a part of the circumferential direction. May be. Further, it may be wound manually or using a jig. After winding the sheet-shaped resin, it is preferable to temporarily fasten it using a tape or the like on the contracted tube.

"Sheet resin"
The sheet-like resin used in the present embodiment is made of at least one material selected from the group consisting of a thermoplastic resin, a photosensitive resin composition, and a thermosetting resin composition.
Hereinafter, the photosensitive resin composition and the thermosetting resin composition may be simply referred to as “resin composition”, and the photosensitive resin cured product and the thermosetting resin cured product may be simply referred to as “resin cured product”.
As a sheet-like resin, a photosensitive resin cured product or a thermosetting resin cured product on a sheet-like support made of a thermoplastic resin from the viewpoints of laser engraving property, image formability, flexibility, mechanical strength securing, etc. It is preferable that it is a sheet-like laminated body with which is laminated | stacked.

A sheet-like resin is defined as a solid resin at 20 ° C. That is, it means that the shape of the sheet is maintained without flowing.
The thickness of the sheet-like resin is preferably from 0.1 mm to 5 mm.
If the thickness of the sheet-like resin is within this range, it can be easily wound on a heat-shrinkable tube, and can be used for printing applications such as flexographic printing, dry offset printing, and gravure printing.

  The sheet-like resin is a photosensitive resin cured product or a thermosetting resin obtained by molding a photosensitive resin composition or a thermosetting resin composition that is liquid at 20 ° C. into a sheet, and then photocuring or thermosetting. It may be a cured product.

Since the laser beam (α) used for welding the heat-shrinkable tube and the sheet-shaped resin is irradiated from the sheet-shaped resin side, the sheet-shaped resin has a high light transmittance with respect to the laser beam (α). It is preferable.
The sheet-like resin is preferably a material through which the laser beam (α) to be used is transmitted from the viewpoint of suppressing deformation and ensuring thickness accuracy. The light transmittance at the oscillation wavelength of the laser beam (α) to be used is From the viewpoint of suppression of ablation by light (α) and suppression of deformation by heat absorption, it is preferably 50% or more and 100% or less, more preferably 70% or more and 100% or less, and further preferably 80% or more and 100%. % Or less.

  The resin composition is selected from the group consisting of polyamide, polyimide, polyurethane, polyester, polycarbonate, polyether polyol, polyvinyl alcohol, vinyl alcohol-vinyl acetate copolymer, styrene-butadiene copolymer, and styrene-isoprene copolymer. It is preferable to contain at least one kind of resin.

The sheet-like support preferably has a thickness of 10 μm or more and 500 μm or less from the viewpoints of dimensional stability, lightness, planar smoothness, and flexibility. The thickness of the sheet-like support is more preferably 50 μm or more and 300 μm or less, and still more preferably 50 μm or more and 200 μm or less.
Examples of the material for the sheet-like support include metals such as nickel, aluminum, and iron, and a thermoplastic resin that is at least one selected from the group consisting of polyester, polyamide, and polyimide.

In the sheet-like resin, the thickness of the photosensitive resin composition or the thermosetting resin composition or the cured resin product thereof is preferably 50 μm or more and 5 mm or less. More preferably, they are 100 micrometers or more and 3 mm or less, More preferably, they are 400 micrometers or more and 1.5 mm or less.
In the sheet-like resin, when the thickness is within the above range, image pattern formability can be ensured and flexibility can be ensured.

  The sheet-like resin preferably contains materials such as polyethane, polyester, polycarbonate, polyether polyol, styrene-butadiene copolymer, and styrene-isoprene copolymer having relatively low hardness for flexographic printing applications. For dry offset printing and gravure printing, it is preferable to contain materials such as polyamide, polyimide, polyvinyl alcohol, vinyl alcohol-vinyl acetate copolymer, and polycarbonate having relatively high hardness.

[Step (4)]
In the present embodiment, the step of bringing the sheet-shaped resin into contact with the contracted tube surface is preferably such that the sheet-shaped resin and the contracted tube are in close contact with each other, and the pressure is applied using a jig from above the sheet-shaped resin. It is preferable to apply.

[Step (5)]
In the present embodiment, the step of irradiating the contacted portion with the laser beam (α) to bond the laser beam (α) to the interface between the contracted tube and the sheet-shaped resin is performed from the sheet-shaped resin side. preferable. Moreover, it is preferable that laser light ((alpha)) is irradiated in the state which the sheet-like resin and the shrunk tube contact | adhered.

In the present embodiment, in the step of irradiating and bonding the heat-shrinkable tube and the sheet-shaped resin with laser light (α), the laser light (α) is focused on the interface between the tube and the sheet-shaped resin. It is preferable to include a process.
Since the energy of the laser beam can be increased by focusing the laser beam (α) on the interface, the laser beam (α) can be bonded efficiently.

[Laser beam (α)]
As the laser beam (α), a laser beam having an oscillation wavelength in the near infrared region having a wavelength of 700 nm to 3 μm is preferable from the viewpoint of light transmittance to the sheet-like resin. More preferably, they are 700 nm or more and 2 micrometers or less, More preferably, they are 800 nm or more and 1100 nm or less.

YAG laser, YVO ₄ laser, YLF laser, titanium sapphire laser, Alexandrite laser, fiber laser doped with Er or Yb can be mentioned as preferable lasers.

The laser beam (α) may be a continuous wave laser or a pulsed laser.
In the case of a pulsed laser, the half-value time width of the laser pulse is preferably 1 nanosecond or more and 50 milliseconds or less. More preferably, they are 5 nanoseconds or more and 50 microseconds or less, More preferably, they are 10 nanoseconds or more and 1 microsecond or less.
If the half-value time width of the pulse is within the above range, welding can be sufficiently performed in the thermal mode.

  Even in the case of using a continuous wave laser, it is possible to convert laser light in a pulse form by using an electro-optic element or an acousto-optic element.

The average output of the laser beam (α) is preferably 0.01 W or more and 200 W or less. A more preferable range is 0.1 W or more and 100 W or less, and further preferably 1 W or more and 50 W or less.
When the average output of the laser beam (α) is within the above range, it is possible to sufficiently secure the adhesive strength by welding, and it is possible to reduce the cost of the laser light source. The diameter of the laser beam applied to the contact interface between the cylindrical support (a) and the sheet-like resin can be reduced using a lens.

The beam diameter of the laser beam (α) is preferably 1 μm or more and 5 mm or less. More preferably, they are 10 micrometers or more and 4 mm or less, More preferably, they are 100 micrometers or more and 3 mm or less.
If the beam diameter of the laser beam (α) is within the above range, it is possible to adhere the sheet-like resin on the cylindrical support (a) with high productivity without using an expensive high-power laser. Adhesion is possible.

  The beam diameter at the focal point of the laser beam (α) is preferably 1 μm or more and 5 mm or less, more preferably 10 μm or more and 3 mm or less, and further preferably 100 μm or more and 1 mm or less from the viewpoint of the adhesion processing speed. .

  In the present embodiment, from the viewpoint of ensuring the pattern formation accuracy of laser engraving, the photosensitive resin composition and / or thermosetting resin composition for forming the sheet-like resin includes the resin (b) and the organic compound (c ) Is preferably contained.

[Resin (b)]
The number average molecular weight of the resin (b) used in the present embodiment is 1000 or more and 300,000 or less, more preferably 2000 or more and 200,000 or less, and further preferably 5000 or more and 150,000 or less.
If the number average molecular weight of the resin (b) is 1000 or more, the cured resin produced by crosslinking later can maintain the strength and withstand repeated use.
When the number average molecular weight of the resin (b) is 300,000 or less, the resin composition can be molded into a sheet without excessively increasing the melt viscosity during extrusion molding.

  In the present embodiment, the number average molecular weight is a value measured by gel permeation chromatography, calibrated with polystyrene having a known molecular weight, and converted.

The resin (b) may have a polymerizable unsaturated group in the molecule, and a preferred compound includes a polymer having an average of 0.7 or more polymerizable unsaturated groups per molecule.
If the average number of polymerizable unsaturated groups per molecule is 0.7 or more, the resin cured product obtained from the resin composition has excellent mechanical strength and good durability, and is particularly repetitive as a printing substrate. It is preferable that it can withstand the use of
Considering the mechanical strength of the cured resin, the number of polymerizable unsaturated groups in the resin (b) is preferably 0.7 or more and more preferably 1 or more per molecule. The upper limit of the number of polymerizable unsaturated groups per molecule is not particularly limited, but is preferably 20 or less. If it is 20 or less, the shrinkage | contraction at the time of hardening can be suppressed low, and generation | occurrence | production of the crack etc. in the surface vicinity can also be suppressed.

  In the present embodiment, having a polymerizable unsaturated group in the molecule means that the polymerizable unsaturated group is directly in the end of the polymer main chain, the end of the polymer side chain, in the polymer main chain, and in the polymer side chain. This includes cases where groups are attached.

Examples of the resin (b) include compounds having a polymerizable unsaturated group in the molecule with a polymer as shown below as a skeleton.
Examples of polymers include polyolefins such as polyethylene and polypropylene; polydienes such as polybutadiene and polyisoprene; polyhaloolefins such as polyvinyl chloride and polyvinylidene chloride; polystyrene, polyacrylonitrile, polyvinyl alcohol, polyvinyl acetate, polyvinyl acetal , Polymers having a hetero atom in the main chain such as polyacrylic acid, poly (meth) acrylic acid esters, poly (meth) acrylamide, polyester, polycarbonate, polyacetal, polyurethane, polyamide, polyurea, polyether polyol, and polyimide, One or two selected from the group consisting of vinyl alcohol-vinyl acetate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer and the like It may be used or more polymers. When using a plurality of polymers, either a copolymer or a blend may be used.

When a flexible relief image is required as in flexographic printing plate applications, as part of the resin (b), a liquid resin having a glass transition temperature of 20 ° C. or lower, preferably a liquid resin having a glass transition temperature of 0 ° C. or lower. Can also be added.
Liquid resins include, for example, hydrocarbons such as polyethylene, polybutadiene, hydrogenated polybutadiene, polyisoprene, and hydrogenated poisoprene; polyesters such as adipate and polycaprolactone; polyethylene such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol Examples include ethers; aliphatic polycarbonates; silicones such as polydimethylsiloxane; polymers of (meth) acrylic acid and / or derivatives thereof, and mixtures and copolymers thereof.
The content of the liquid resin is preferably 30% by mass or more and 100% by mass or less based on the entire resin (b) from the viewpoint of ensuring the mechanical properties of the cured product.
As the liquid resin, unsaturated polyurethanes having a polycarbonate structure are preferable from the viewpoint of weather resistance. Examples of the unsaturated polyurethane include a resin having a polymerizable unsaturated group such as an acrylate group or a methacrylate group at the end of the polyurethane molecular chain, and a resin having a double bond in the polyurethane molecular chain.

As a method of introducing a polymerizable unsaturated group into the molecule of the resin (b), for example, a method of directly polymerizing using a monomer having a polymerizable unsaturated group introduced into the molecular end or molecular chain thereof. Can be mentioned.
As another method, a method in which a resin (polymer) and a compound having a polymerizable unsaturated group are reacted to introduce a polymerizable unsaturated group into the terminal of the resin can also be mentioned. Specifically, it has a plurality of reactive groups such as a hydroxyl group, amino group, epoxy group, carboxyl group, acid anhydride group, ketone group, hydrazine residue, isocyanate group, isothiocyanate group, cyclic carbonate group, and ester group. The compound is allowed to react with a binder having a plurality of functional groups capable of binding to a reactive group (for example, when the reactive group is a hydroxyl group or an amino group, examples of the binder include polyisocyanate), and the molecular weight. The resin obtained by the reaction is reacted with a compound having a functional group capable of reacting with the terminal binding group of the resin and a polymerizable unsaturated group. Then, a polymerizable unsaturated group is introduced into the terminal of the resin.

When the cured resin is used as a printing substrate for laser engraving, it is preferable to use a polymer having high thermal decomposability as the resin (b). For example, polymers having α-methylstyrene, methacrylic acid ester, and acrylic acid ester units, or a carbonate bond and a carbamate bond in the molecule are known as highly thermally decomposable compounds.
As an index of thermal decomposability, thermogravimetric data obtained by measuring weight loss when a sample is heated in an inert gas atmosphere can be used.

As a preferable resin (b), it is preferable that the temperature at which the amount is reduced by half is in the range of 150 ° C. or more and 450 ° C. or less from the viewpoint of ensuring laser engraving speed and accuracy of the pattern edge portion obtained by laser engraving. More preferably, it is 250 ° C. or higher and 400 ° C. or lower, and further preferably 250 ° C. or higher and 380 ° C. or lower.
From the viewpoint of ensuring the laser engraving speed and ensuring the accuracy of the pattern edge portion obtained by laser engraving, a compound in which thermal decomposition occurs in a narrow temperature range is preferable. As an indicator thereof, in thermogravimetric analysis, the difference between the temperature at which the weight decreases to 80% of the initial weight and the temperature at which the weight decreases to 20% of the initial weight is preferably 100 ° C. or less, more preferably It is 80 ° C. or lower, more preferably 60 ° C. or lower.

[Organic compound (c)]
The organic compound (c) is a compound having a polymerizable unsaturated group involved in radical polymerization reaction or ring-opening polymerization reaction, and the number average molecular weight is 1000 or less in consideration of easiness of dilution with the resin (b). It is preferable that
Examples of the organic compound (c) include olefins such as ethylene, propylene, styrene and divinylbenzene; acetylenes; (meth) acrylic acid and derivatives thereof; haloolefins; unsaturated nitriles such as acrylonitrile; (meth) acrylamide Allyl compounds such as allyl alcohol and allyl isocyanate; unsaturated dicarboxylic acids such as maleic anhydride, maleic acid, fumaric acid, and itaconic acid and their derivatives; vinyl acetates; N-vinylpyrrolidone; Carbazole; cyanate esters and the like.
As the organic compound (c), derivatives such as (meth) acrylic acid and (meth) acrylic acid ester are preferable from the viewpoint of variety and price.

As the derivative, an alicyclic compound having a functional group such as a cycloalkyl group, a bicycloalkyl group, a cycloalkene group, and a bicycloalkene group ; a functional group such as a benzyl group, a phenyl group, a phenoxy group, a methylstyryl group, and a styryl group An aromatic compound having a group; an ester compound or an amide compound such as a compound having a functional group such as an alkyl group, a halogenated alkyl group, an alkoxyalkyl group, a hydroxyalkyl group, an aminoalkyl group, a tetrahydrofurfuryl group, and a glycidyl group; And ester compounds of polyhydric alcohols such as alkylene glycol, polyoxyalkylene glycol, (alkyl / allyloxy) polyalkylene glycol and trimethylolpropane.

  The organic compound (c) having a polymerizable unsaturated group can be selected from one or more compounds depending on the purpose. For example, when a cylindrical printing original plate is used as a printing plate, a long-chain aliphatic, alicyclic, or aromatic is used as the organic compound (c) in order to suppress swelling with respect to an organic solvent such as alcohol or ester as a printing ink solvent. It is preferable to select at least one kind of group derivative.

  In order to increase the mechanical strength of the cured resin, it is preferable to select at least one compound having a substituent (functional group) such as an alicyclic group or an aromatic group as the organic compound (c). The compound having a substituent such as an alicyclic group or an aromatic group is preferably 20% by mass or more and 100% by mass or less, more preferably 50% by mass or more and 100% by mass with respect to the total amount of the organic compound (c). It is as follows.

  The sheet resin in the present embodiment may be a photosensitive resin composition or a photosensitive resin cured product, and preferably contains a photopolymerization initiator in the photosensitive resin composition.

[Photopolymerization initiator]
In the present embodiment, the resin composition is irradiated with light and cured to form a laser engraving layer. As light, in addition to ultraviolet rays and visible rays, high energy rays such as electron beams and X-rays can be used. In particular, when photocuring using ultraviolet light or visible light, it is preferable to add a photopolymerization initiator. As the photopolymerization initiator, it is preferable to add a hydrogen abstraction type photopolymerization initiator (d) and / or a decay type photopolymerization initiator (e).

[Hydrogen extraction type photopolymerization initiator (d)]
Although it does not specifically limit as a hydrogen abstraction type photoinitiator (d), It is preferable to use an aromatic ketone. Aromatic ketone is efficiently converted into an excited triplet state by photoexcitation, and a chemical reaction mechanism has been proposed in which this excited triplet state extracts radicals from surrounding media to generate radicals. The generated radical is considered to be involved in the photocrosslinking reaction. Any compound can be used as the hydrogen abstraction type photopolymerization initiator (d) used in the present embodiment as long as it is a compound capable of generating a radical by extracting hydrogen from the surrounding medium through an excited triplet state.

  Examples of aromatic ketones include benzophenones, Michler ketones, xanthenes, thioxanthones, and anthraquinones, and it is preferable to use at least one compound selected from these groups. Benzophenones refer to benzophenone or derivatives thereof, specifically 3,3 ′, 4,4′-benzophenone tetracarboxylic anhydride, 3,3 ′, 4,4′-tetramethoxybenzophenone, and the like. Michler ketones refer to Michler ketone and its derivatives. Xanthenes refer to derivatives substituted with xanthene and an alkyl group, phenyl group, or halogen group. Thioxanthones refer to thioxanthone and derivatives substituted with an alkyl group, a phenyl group, and a halogen group, and examples thereof include ethylthioxanthone, methylthioxanthone, and chlorothioxanthone. Anthraquinones are anthraquinone and derivatives substituted with alkyl groups, phenyl groups, halogen groups, and the like.

  The addition amount of the hydrogen abstraction type photopolymerization initiator is preferably 0.3% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 5% by mass or less of the total amount of the photosensitive resin composition. If the addition amount is within this range, when the liquid photosensitive resin composition is photocured in the atmosphere, the surface of the cured product can be sufficiently secured, and no cracks or the like are generated on the surface during long-term storage. , Can ensure the fading.

[Collapse photopolymerization initiator (e)]
The decay type photopolymerization initiator (e) refers to a compound that generates an active radical by generating a cleavage reaction in the molecule after light absorption, and is not particularly limited. Specific examples include benzoin alkyl ethers, 2,2-dialkoxy-2-phenylacetophenones, acetophenones, acyloxime esters, azo compounds, organic sulfur compounds, acylphosphine oxides, diketones, and the like. It is preferable to use at least one compound selected from these groups.

  Examples of benzoin alkyl ethers include benzoin isopropyl ether and benzoin isobutyl ether. Examples of 2,2-dialkoxy-2-phenylacetophenones include 2,2-dimethoxy-2-phenylacetophenone and 2,2-diethoxy-2-phenylacetophenone. Examples of acetophenones include acetophenone, trichloroacetophenone, 1-hydroxycyclohexylphenylacetophenone, 2,2-diethoxyacetophenone, and the like. Examples of acyl oxime esters include 1-phenyl-1,2-propanedione-2- (o-benzoyl) oxime. Examples of the azo compound include azobisisobutyronitrile, diazonium compound, and tetrazene compound. Examples of diketones include benzyl and methylbenzoyl formate.

  The addition amount of the collapsible photopolymerization initiator is preferably 0.3% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 5% by mass or less of the total amount of the photosensitive resin composition. If the addition amount is within this range, when the liquid photosensitive resin composition is photocured in the air, the curability inside the cured product can be sufficiently secured.

  A compound having a site functioning as a hydrogen abstraction type photopolymerization initiator and a site functioning as a decay type photopolymerization initiator in the same molecule can also be used as the photopolymerization initiator. Examples of the photopolymerization initiator include α-aminoacetophenones such as 2-methyl-1- (4-methylthiophenyl) -2-morpholino-propan-1-one, 2-benzyl-2-dimethyl. Mention may be made of compounds such as amino-1- (4-morpholinophenyl) -butanone.

  The addition amount of the photopolymerization initiator having a site functioning as a hydrogen abstraction type photopolymerization initiator and a site functioning as a decay type photopolymerization initiator in the same molecule is 0.3 mass of the total amount of the photosensitive resin composition. % To 10% by mass, more preferably 0.5% to 3% by mass. When the addition amount is within this range, the mechanical properties of the cured product can be sufficiently ensured even when the photosensitive resin composition is photocured in the atmosphere.

[Photoacid generator, photobase generator]
In this embodiment, a compound that generates an acid or a base by light irradiation can be used as a photopolymerization initiator. A compound having a functional group that undergoes a ring-opening polymerization reaction, such as an epoxy compound or an oxetane compound, can be subjected to ring-opening polymerization.

[Thermal polymerization initiator]
In the present embodiment, since the sheet resin may be a thermosetting resin composition or a cured product thereof, the thermosetting resin composition preferably contains a thermal polymerization initiator. As the thermal polymerization initiator, suitable compounds are all thermal polymerization initiators that can be used in radical polymerization reactions and ring-opening polymerization reactions. Examples of thermal polymerization initiators used in radical polymerization reactions include organic peroxides, inorganic peroxides, organic silicon peroxides, hydroperoxides, azo compounds, thiol compounds, phenol resins, amino resins, halogen compounds, aldehyde compounds Etc. Moreover, as a thermal polymerization initiator used for the ring-opening polymerization reaction, it is preferable to select a latent thermal polymerization initiator in which a thermal polymerization initiator is placed in a microcapsule.

The thermal polymerization initiator is preferably liquid at 20 ° C. from the viewpoint of easy mixing with the resin (b) or the organic compound (c).
The content of the thermal polymerization initiator is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 5% by mass or less, and still more preferably 1% with respect to the total amount of the thermosetting resin composition. It is from 5% by mass to 5% by mass. If the content rate of a thermopolymerization initiator is the said range, a thermosetting resin composition can fully be hardened and it becomes possible to reduce the adhesiveness of the surface of a thermosetting material.

  The selection of a suitable thermal polymerization initiator is particularly important in carrying out the method of the present embodiment. The thermal stability of the thermal polymerization initiator is usually determined by the method with a 10-hour half-life temperature of 10 h-t1 / 2, i.e. 50% of the initial amount of thermal polymerization initiator decomposes after 10 hours to free radicals. Is indicated by the temperature at which Further details on this are given in “Encyclopedia of Polymer Science and Engineering”, Vol. 11, page 1 et seq., John Wiley & Sons, New York, 1988.

Suitable thermal polymerization initiators typically have a 10 h-t1 / 2 of preferably at least 60 ° C, more preferably at least 70 ° C. Especially preferably, it is 10 h-t1 / 2 of 80 to 150 degreeC.
As the thermopolymerization initiator, an organic peroxide is particularly preferable from the viewpoint of thermosetting and compatibility with the thermosetting resin composition. Specific examples of the compounds include peroxyesters such as t-butyl peroctanoate, t-amyl peroctanoate, t-butyl peroxyisobutyrate, t-butyl peroxymaleate, t-amyl perbenzoate, diperoxy Di-t-butyl phthalate, t-butyl perbenzoate, t-butyl peracetate and 2,5-di (benzoylperoxy) -2,5-dimethylhexane, certain diperoxyketals such as 1, 1-di (t-amylperoxy) cyclohexane, 1,1-di (t-butylperoxy) cyclohexane, 2,2-di (t-butylperoxy) butane and ethyl 3,3-di (t-butylperoxy) butyrate Certain dialkyl peroxides such as di-t-butyl peroxide, t-butylcumyl peroxide, di- Milperoxide and 2,5-di (t-butylperoxy) -2,5-dimethylhexane, certain diacyl peroxides such as dibenzoyl peroxide and diacetyl peroxide, certain t-alkyl hydroperoxides such as t-butyl Hydroperoxide, t-amyl hydroperoxide, pinane hydroperoxide and cumyl hydroperoxide.

  A preferable example of forming a cushion layer containing bubbles is an azo compound. For example, 1- (t-butylazo) formamide, 2- (t-butylazo) isobutyronitrile, 1- (t-butylazo) cyclohexanecarbonitrile, 2- (t-butylazo) -2-methylbutanenitrile, 2, 2'-azobis (2-acetoxypropane), 1,1'-azobis (cyclohexanecarbonitrile), 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2-methylbutanenitrile), etc. It is a compound of this.

[Fine particles]
Inorganic fine particles, organic fine particles, and organic-inorganic composite fine particles can be added to the sheet-like resin of the present embodiment. By adding these fine particles, it is possible to improve the mechanical properties of the sheet-like resin obtained, improve the wettability of the surface of the sheet-like resin, or adjust the viscoelastic properties of the sheet-like resin. The material of the inorganic fine particles or organic fine particles is not particularly limited, and known materials can be used. Examples of the organic / inorganic composite fine particles include fine particles in which an organic layer or organic fine particles are formed on the surface of the inorganic fine particles, or fine particles in which an inorganic layer or inorganic fine particles are formed on the surface of the organic fine particles.

  In the present embodiment, for the purpose of improving the mechanical properties of the sheet-like resin, high-rigidity inorganic fine particles such as silicon nitride, boron nitride, and silicon carbide, or organic fine particles such as polyimide can be used. Furthermore, for the purpose of improving the solvent resistance of the obtained sheet-like resin, inorganic fine particles or organic fine particles formed of a material having a good swelling property in the solvent to be used can be added.

  When forming an uneven pattern on the surface of the cylindrical printing original plate by the laser engraving method, inorganic porous fine particles having excellent adsorption and removal characteristics of the viscous liquid residue generated in the laser engraving process may be added. Although not particularly limited, for example, porous silica, mesoporous silica, silica-zirconia porous gel, porous alumina, porous glass and the like can be mentioned.

  The fine particles used in the present embodiment preferably have a number average particle diameter of 0.01 to 100 μm. When fine particles having this number average particle size range are used, there is no inconvenience such as an increase in viscosity, entrainment of bubbles, and generation of a large amount of dust when mixing with the resin (b) and the organic compound (c). In addition, unevenness does not occur on the surface of the sheet-like resin. A more preferable range of the average particle diameter is 0.1 to 20 μm, and a further preferable range is 1 to 10 μm. The average particle size of the fine particles of the present embodiment is a value measured using a laser scattering type particle size distribution measuring device.

  The particle shape of the fine particles is not particularly limited, and spherical, flat, needle-like, amorphous, or particles having protrusions on the surface can be used. In particular, spherical particles are preferable from the viewpoint of wear resistance.

The surface of the fine particles may be coated with a silane coupling agent, a titanium coupling agent, or other organic compound, and subjected to surface modification treatment to make the particles more hydrophilic or hydrophobic.
In the present embodiment, one kind or two or more kinds of these fine particles can be selected.

[Composition ratio of resin composition]
The ratio of the resin (b), the organic compound (c), and the fine particles in the sheet-like resin of the present embodiment is usually 5 to 200 parts by mass of the organic compound (c) with respect to 100 parts by mass of the resin (b). Preferably, the range of 20-100 mass parts is more preferable. Moreover, 1-100 mass parts is preferable, and the range of 2-50 mass parts is more preferable. A more preferable range is 2 to 20 parts by mass.
When the ratio of the organic compound (c) is in the above range, it is easy to balance the hardness and tensile strength / elongation of the obtained sheet-like resin, and the shrinkage at the time of curing is within a small range to ensure thickness accuracy. Can do.

  A polymerization inhibitor, an ultraviolet absorber, a lubricant, a surfactant, a plasticizer, a fragrance and the like can be added to the sheet-like resin depending on the purpose and purpose.

[Method for producing sheet-like resin]
In the present embodiment, an existing resin molding method can be used as a method for producing a sheet-like resin. For example, a casting method, a method of spraying resin using a spray, such as a method of extruding a resin from a nozzle or a die with a machine such as a pump or an extruder, adjusting the thickness with a blade, adjusting the thickness by calendaring with a roll, etc. it can. In that case, it is also possible to perform molding while heating in a range that does not cause thermal decomposition of the resin. Moreover, you may perform a rolling process, a grinding process, etc. as needed.

[Photocuring method]
When the sheet-like resin in the present embodiment is a photosensitive resin composition, the molded photosensitive resin composition is cross-linked by light irradiation to form a cured photosensitive resin. Further, it can be crosslinked by light irradiation while molding. Examples of the light source used for curing include a high pressure mercury lamp, an ultrahigh pressure mercury lamp, an ultraviolet fluorescent lamp, a germicidal lamp, a carbon arc lamp, a xenon lamp, and a metal halide lamp. The light irradiated to the photosensitive resin composition preferably has light having a wavelength of 200 nm to 400 nm. In particular, since many hydrogen abstraction type photopolymerization initiators have strong light absorption in this wavelength region, when having light with a wavelength of 200 nm to 400 nm, sufficient curability of the photosensitive resin cured product layer surface is ensured. be able to. The light source used for photocuring may be one type, but since the curability of the resin may be improved by curing using two or more types of light sources having different wavelengths, two or more types of light sources may be used. There is no problem.

[Thermosetting method]
When the curable resin composition is a thermosetting resin composition, a thermosetting resin cured product is obtained by heat treatment.
Examples of the heating method include a method of irradiating infrared rays, a method of exposing to an atmosphere heated by an oven, a method of contacting an object such as a heated metal, and the like. The heating temperature is selected according to the type of thermal polymerization initiator.

[Cushion layer]
In the present embodiment, a cushion layer made of an elastomer can be formed on the sheet-like resin. The cushion layer is preferably an elastomer layer having a Shore A hardness of 10 to 70 degrees, or an ASKER-C hardness of 20 to 85 degrees as measured with an ASKER-C hardness meter. When the Shore A hardness is 10 degrees or more, or the ASKER-C hardness is 20 degrees or more, the print quality can be ensured because it is appropriately deformed. Moreover, if Shore A hardness is 70 degrees or less or ASKER-C hardness is 85 degrees or less, it can play the role as a cushion layer. A more preferable range of Shore A hardness is 20 to 60 degrees, and an ASKER-C hardness is 45 to 75 degrees. The Shore A hardness and the ASKER-C hardness are preferably selected depending on the material used for the cushion layer. The difference between the two types of hardness stems from the difference in the shape of the pushers of the hardness meter used for measurement. In the case of a uniform resin composition, it is preferable to use Shore A hardness, and in the case of a non-uniform resin composition such as a foamable base material such as foamed polyurethane and foamed polyethylene, it is preferable to use ASKER-C hardness. ASKER-C hardness is a measuring method based on JIS K7312 standard.

The cushion layer is not particularly limited, and any cushion layer may be used as long as it has rubber elasticity, such as a thermoplastic elastomer, a photocurable elastomer, and a thermosetting elastomer. In particular, from the viewpoint of processability to a sheet-like or cylindrical printing plate, it is simple and preferable to use a liquid photosensitive resin composition that is cured by light and to use a material that becomes an elastomer after curing.
It is preferable that the cushion layer contains a photocurable resin cured product and contains bubbles or organic fine particles. In addition, it is preferable to use organic microparticles that are hollow microcapsules and that have inorganic microparticles attached to the surface of the hollow microcapsules. The average particle size of the organic fine particles is preferably 1 μm or more and 500 μm or less. A more preferable range is 10 μm or more and 300 μm or less, and further preferably 80 μm or more and 200 μm or less.

The density of the cushion layer is preferably 0.1 g / cm ³ or more and 0.9 g / cm ³ or less. More preferably, it is 0.3 g / cm ³ or more and 0.7 g / cm ³ or less, and further preferably 0.4 g / cm ³ or more and 0.6 g / cm ³ or less.
If the density of the cushion layer is within this range, the impact applied to the laser engraving layer in the printing process can be sufficiently absorbed.

  Specific examples of the thermoplastic elastomer used for the cushion layer include SBS (polystyrene-polybutadiene-polystyrene), SIS (polystyrene-polyisoprene-polystyrene), SEBS (polystyrene-polyethylene / polybutylene-polystyrene), which are styrenic thermoplastic elastomers, and the like. Olefin-based thermoplastic elastomer, urethane-based thermoplastic elastomer, ester-based thermoplastic elastomer, amide-based thermoplastic elastomer, silicon-based thermoplastic elastomer, fluorine-based thermoplastic elastomer, and the like.

  The photocurable elastomer includes a thermoplastic elastomer mixed with a photopolymerizable monomer, a plasticizer, a photopolymerization initiator, etc., and a liquid photosensitive resin composition prepared by mixing a photopolymerizable monomer, a photopolymerization initiator, etc. with a liquid resin. Things can be mentioned. In this embodiment, unlike the design concept of the photosensitive resin composition, in which the function of forming a fine pattern is an important factor, it is not necessary to form a fine pattern using light, and it is cured by overall exposure. Therefore, it is only necessary to ensure the necessary mechanical strength, so that the degree of freedom in selecting the material is extremely high.

Non-sulfur cross-linkable rubber using a compound such as sulfur cross-linkable rubber, organic peroxide, phenol resin initial condensate, quinone dioxime, metal oxide, thiourea as a cross-linking agent may be used.
It is also possible to use an elastomer obtained by three-dimensional crosslinking using a curing agent that reacts with telechelic liquid rubber.

  The cushion layer may be made of foamed polyurethane, foamed polyethylene, or the like and may have independent or open cells in the layer, and a commercially available cushion material or cushion tape may be used. Alternatively, an adhesive or a pressure-sensitive adhesive may be applied on both sides.

[Method for producing laser-engraved cylindrical printing plate]
The manufacturing method of the cylindrical printing plate for laser engraving of this embodiment is a manufacturing method including a laser engraving step of forming a concave pattern by irradiating a cylindrical printing original plate with laser light (β).

[Laser engraving]
In the present embodiment, when the cured photosensitive resin is used as a printing original plate for forming a pattern using a laser engraving method, the laser engraving method uses a computer as digital data for an image to be formed. Operate the laser device to create a relief image on the printing substrate. The laser beam (β) used for laser engraving may be any as long as the original plate includes a wavelength having absorption, but in order to perform engraving at a high speed, a high output is preferable, Infrared or infrared emitting solid lasers such as carbon dioxide laser, YAG laser and semiconductor laser are preferred. Further, the second harmonic of a YAG laser having an oscillation wavelength in the visible light region, a copper vapor laser, an ultraviolet laser having an oscillation wavelength in the ultraviolet region, such as an excimer laser, and a YAG laser that has been wavelength-converted to the third or fourth harmonic are: It can be ablated by cutting the bonds of organic molecules and is suitable for fine processing. The laser may be continuous irradiation or pulse irradiation.

  Engraving with a laser beam (β) is performed in an oxygen-containing gas, generally in the presence of air or an air stream, but can also be performed in a carbon dioxide gas or a nitrogen gas. After engraving is finished, the powdery or liquid substance slightly generated on the relief printing plate surface is washed with an appropriate method such as water containing a solvent or a surfactant, or a water-based cleaning agent is irradiated by a high-pressure spray or the like. Alternatively, it may be removed using a method of irradiating high-pressure steam.

[Surface treatment of cylindrical printing plate]
In this embodiment, after engraving to irradiate a laser beam (β) to form a concavo-convex pattern, following the step of removing powdery or viscous liquid residue remaining on the plate surface, the pattern is formed on the printing plate surface. Post-exposure by irradiating light with a wavelength of 200 nm to 450 nm can also be performed. This is an effective method for removing tack on the surface. The post-exposure may be performed in any environment such as air, inert gas atmosphere, and water. This is particularly effective when the photosensitive resin composition used contains a hydrogen abstraction type photopolymerization initiator. Furthermore, before the post-exposure step, the printing plate surface may be treated and exposed to a treatment liquid containing a hydrogen abstraction type photopolymerization initiator. Moreover, you may expose in the state which immersed the printing plate in the process liquid containing a hydrogen drawing-type photoinitiator.

[Usage]
Applications of the sheet-like printing plate produced in this embodiment include flexographic printing, dry offset printing, and gravure printing. Narrow webs such as flexographic label printing, which require a highly accurate printed matter, and curved offset printing such as can offset printing and tube printing are preferred applications.

In dry offset printing, when the ink contains an aliphatic hydrocarbon and / or an aromatic hydrocarbon, the sheet-like resin preferably contains a polycarbonate, polyurethane, polyamide, polyvinyl alcohol, or a vinyl alcohol-vinyl acetate copolymer. These resin materials are preferable because they have resistance to the above-mentioned solvents.
Examples of aliphatic hydrocarbons include compounds such as hexane, heptane, octane, nonane, decane, cyclohexane, methylcyclohexane, cyclooctane, cyclodecane, dipentene, rubber volatile oil, mineral spirits, and high boiling point petroleum solvent (ink oil). it can.
Examples of the aromatic hydrocarbon include compounds such as toluene, xylene, dimethylbenzene, dichlorobenzene, solvent naphtha, and tetralin.

  Hereinafter, the present embodiment will be described more specifically with reference to examples and comparative examples. However, the present embodiment is not limited only to these examples. The measurement method and evaluation method used in this embodiment are as follows.

(1) Laser engraving Laser engraving is a carbon dioxide laser engraving machine (ZED-mini-1000, UK, manufactured by ZED, USA, coherent, equipped with a 250 W carbon dioxide laser with an oscillation wavelength of 10.6 μm) It was performed using. Engraving was performed by creating a dot pattern (120 lines / inch, area ratio 10%). The engraving depth was 0.55 mm.

(2) Viscosity The viscosity of the resin composition was measured at 20 ° C. using a B-type viscometer (trademark, B8H type; manufactured by Tokyo Keiki Co., Ltd., Japan).

(3) Measurement of number average molecular weight The number average molecular weights of the resin (b) and the organic compound (c) were determined by conversion with polystyrene having a known molecular weight using a gel permeation chromatography method (GPC method). Using a high-speed GPC apparatus (Japan, Tosoh Corporation, HLC-8020) and a polystyrene-filled column (trademark: TSKgel GMHXL; Japan, Tosoh Corporation), the measurement was performed with tetrahydrofuran. The column temperature was set to 40 ° C. As a sample to be injected into the GPC apparatus, a tetrahydrofuran solution having a resin concentration of 1% by mass was prepared, and the injection amount was 10 μL. A differential refractometer was used as the detector.

(4) Measurement of heat shrinkage rate A 100 mm square film sample was placed in an oven set at 80 ° C. and treated for 30 minutes in a freely shrinkable state, then the amount of shrinkage of the film was obtained, and the value divided by the original dimension was obtained. Expressed as a percentage. The average value of the values in the vertical direction and the horizontal direction was defined as the heat shrinkage rate.

(5) Measurement of centerline average surface roughness Using a surface roughness measuring machine “SE500” manufactured by Kosaka Laboratory, stylus R (radius of curvature) 2 μm, cutoff λc = 0.8 mm, measurement length 4 mm The measurement was performed under the condition of a feed rate of 0.5 m / sec, and the center line average surface roughness Ra was measured.

(Production Example 1)
A 1 L separable flask equipped with a thermometer, a stirrer, and a refluxer is a polycarbonate diol manufactured by Asahi Kasei Co., Ltd., “PCDL (registered trademark) L4672” (number average molecular weight 1990, OH value 56.4) 447.24 g and tri After adding 30.83 g of diisocyanate and reacting at 80 ° C. with heating for about 3 hours, 14.83 g of 2-methacryloyloxyisocyanate was added, and the mixture was further reacted for about 3 hours. A resin (A) having a number average molecular weight of about 10,000 having an average of about 2 polymerizable unsaturated groups per molecule) was produced. This resin (a) was in the form of a syrup at 20 ° C., flowed when an external force was applied, and did not recover its original shape even when the external force was removed.

Example 1
[Production of heat-shrinkable tube]
Polyethylene terephthalate (manufactured by Unitika) and carbon black (manufactured by Tokai Carbon Co., “TB # A700F”) at a ratio of 10% by mass using a small-capacity pressure type kneader (manufactured by Moriyama Co., “D1-5”). Mix with heating to ° C. After cooling, it was pulverized, melted with a biaxial extruder (“KZW-TW”, manufactured by Technobel), extruded from a die, formed into a film shape, and then biaxially stretched to a thickness of 50 μm. Both ends were overlapped by about 3 mm so as to have a diameter about 1 mm larger than the outer diameter of the glass fiber reinforced plastic sleeve, which is a hollow cylindrical support to be used, to form a tube. A part of the heat-shrinkable tube was cut and used for measuring the heat shrinkage rate. As a result, the heat shrinkage rate at 80 ° C. was 30%.
Further, the centerline average surface roughness Ra of the heat-shrinkable tube was 0.2 μm, and the light transmittance was less than 1% in laser light with oscillation wavelengths of 940 nm and 1064 nm.

[Coating on cylindrical support (a)]
A glass fiber reinforced plastic sleeve (made by Polybest, Germany) with an inner diameter of 225 mm, a thickness of 1 mm, and a width of 200 mm mounted on an air cylinder is covered with the produced heat-shrinkable tube and contracted by heating to 120 ° C. And was brought into close contact with the hollow cylindrical support. The centerline average surface roughness Ra of the glass fiber reinforced plastic sleeve used was 1 μm.

[Preparation of sheet resin]
As the resin (b), a polycarbonate polyurethane having a number average molecular weight of about 100,000 (manufactured by Dainichi Seika Co., Ltd., “Resamine (registered trademark) P890”) 70 parts by mass, as the organic compound (c), phenoxyethyl methacrylate (molecular weight 190) 30 parts by mass and trimethylolpropane triacrylate (molecular weight 338) 1 part by mass, as fine particles, porous fine powder silica (manufactured by Fuji Silysia Chemical Co., Ltd., “Cyrosphere (registered trademark) C-1504 (hereinafter abbreviated as C-1504) ) ”, Number average particle diameter 4.5 μm, specific surface area 520 m ² / g, average pore diameter 12 nm, pore volume 1.5 ml / g, loss on ignition 2.5% by mass, oil absorption 290 ml / 100 g) 5 parts by mass, 0.5 parts by mass of benzophenone and 2,2-dimethoxy-2-phenylacetophenone as a photopolymerization initiator As a mass part, 0.5 mass part of 2,6-di-t-butylacetophenone as a stabilizer is mixed at a temperature of 130 ° C. using a small-capacity pressure type kneader (“D1-5” manufactured by Moriyama Co., Ltd.), A photosensitive resin composition was prepared. Using a biaxial extruder (“KZW-TW”, manufactured by Technobel Co., Ltd.), the resulting photosensitive resin composition was placed on a 50 μm thick PET film (manufactured by Toray Industries, Inc.). Then, a sheet-like resin was formed by extruding at a thickness of 0.4 mm and sandwiching it with a 50 μm-thick PET cover sheet (manufactured by Fujimori Kogyo Co., Ltd.) subjected to silicone release treatment. The photosensitive resin composition of sheet-like resin was solid at 20 ° C.
[Manufacture of cylindrical printing original plate]
The obtained sheet-like resin was cut into a width of 180 mm and a length of 710 mm. The cover film was peeled off, and a sheet-shaped resin was wound on a glass fiber reinforced plastic sleeve, and the contracted tube and the PET film of the sheet-shaped resin were brought into contact with each other. For the contact portion, a laser head of a fiber laser (manufactured by SPI, UK, “redENERGY”) was moved in the long axis direction of the hollow cylindrical support to be bonded linearly. The wavelength of the fiber laser used was 1064 nm, the beam diameter was 3 mm, the half-value time width was 20 nanoseconds, the average output was 20 W, and the beam diameter at the focal point was 1 mm. Next, the position for bonding was moved, the entire surface of the sheet-like resin was bonded at a pitch of 5 mm, and both ends were finally welded. The light transmittance of the sheet-like resin at a wavelength of 1064 nm was 95% or more.
While rotating the air cylinder, the light of a metal halide lamp (manufactured by Fusion, “F450V type UV lamp”) was exposed at 350 nm under the condition of 4000 mJ / cm ² , and the photosensitive resin composition of the sheet-like resin was photocured to form a cylinder. An original printing plate was obtained.
The Shore A hardness of the cured photosensitive resin was 50 degrees. Further, the outer diameter of the obtained cylindrical printing original plate was measured with a laser length measuring instrument at five locations on the same circumference and at five locations in the major axis direction. However, the portion where the joint portion of the cured resin sheet was not included was selected for measurement. The outer diameter accuracy was ± 20 μm.
An uneven pattern was formed on the surface of the obtained laser engraved cylindrical printing original plate using a carbon dioxide laser engraving machine.
Eight cylindrical printing plates having a pattern formed on the surface were prepared and set in a dry offset can printing machine (manufactured by Stora Machinery Inc., USA), and eight colors were printed on the surface of the aluminum can. The time required for the operation of attaching the cylindrical printing plate to the air cinder and performing the alignment was within 2 minutes per one. Compared with the time (about 20 minutes per one) required for the operation of attaching and aligning the conventional sheet plate, the time was significantly reduced. Printing on aluminum cans was performed at a speed of 25 lines per second. It was confirmed that the surface of the aluminum can was printed with good print quality. Even after printing 1 million copies, there was no particular problem in adhesion and durability.

(Example 2)
In the same manner as in Example 1, a sheet-like resin was obtained. Before wrapping around a hollow cylindrical support, it is irradiated with 4000 mJ / cm ² (integrated light quantity at 350 nm) with UV light emitted from a chemical lamp (“10R”, Lankoku, Philips) on a glass plate and photocured. It was. Thereafter, in the same manner as in Example 1, a sheet-like resin was wound on a hollow cylindrical support body obtained by thermally shrinking a heat-shrinkable tube, and both were bonded using a semiconductor laser welding apparatus to obtain a cylindrical printing original plate. Produced. The outer diameter system was within ± 15 μm.

(Example 3)
70 parts by mass of resin (a) prepared in Production Example 1 as resin (b), 10 parts by mass of phenoxyethyl methacrylate (molecular weight 190) and 10 parts by mass of polypropylene glycol monomethacrylate (molecular weight 400) as organic compound (c) 5 parts by weight of C-1504 as fine particles, 0.5 part by weight of benzophenone and 0.6 parts by weight of 2,2-dimethoxy-2-phenylacetophenone as a photopolymerization initiator, and 2,6-di-t as a stabilizer -Butyl acetophenone The photosensitive resin composition which mixed 0.5 mass part was prepared. The obtained photosensitive resin composition was liquid at 20 ° C. The viscosity measured using a B-type viscometer was 1200 Pa · s at 20 ° C.
The prepared liquid photosensitive resin composition was applied on a 50 μm-thick polyimide film (Toray DuPont) placed on a glass plate with a thickness of 0.4 mm, and a chemical lamp (Rangoku, Philips) was applied from above and below. , “10R”) was irradiated with 4000 mJ / cm ² of ultraviolet light to obtain a sheet-like resin. A cylindrical printing original plate was produced in the same manner as in Example 2 except that the obtained sheet resin was used.
The accuracy of the outer diameter of the obtained cylindrical printing original plate was ± 20 μm.
Although printing was performed on the surface of the aluminum can in the same manner as in Example 1, no particular problem occurred in terms of print quality.

Example 4
As the resin (b), a polycarbonate polyurethane having a number average molecular weight of about 100,000 (manufactured by Dainichi Seika Co., Ltd., “Resamine (registered trademark) P890”) 70 parts by mass, as the organic compound (c), phenoxyethyl methacrylate (molecular weight 190) 30 parts by mass and 1 part by mass of trimethylolpropane triacrylate (molecular weight 338), 5 parts by mass of C-1504 as fine particles, 0.5 part by mass of 2,6-di-t-butylacetophenone as a stabilizer, small volume Mixing at a temperature of 130 ° C. using a pressure type kneader (manufactured by Moriyama Co., Ltd., “D1-5”), cooling to 70 ° C., and t-butylperoxy-2-ethylhexyl carbonate (Nippon Yushi) as a thermal polymerization initiator 1 part by mass of “Perbutyl E (registered trademark)” manufactured by Co., Ltd. was added to prepare a thermosetting resin composition. The obtained thermosetting resin composition is inserted between a 50 μm-thick PET film (manufactured by Toray Industries, Inc.) whose surface is coated with an adhesive layer and a silicone release-treated PET film (manufactured by Fujimori Kogyo Co., Ltd.). Then, it was hot-pressed with two metal plates. A metal spacer having a thickness of 0.5 mm was inserted between the two metal plates, and heat treatment was performed at 130 ° C. for 30 minutes to obtain a sheet-like resin.
The obtained sheet-like resin was cut into a width of 180 mm and a length of 710 mm. The cover film was peeled off, wound on the same glass fiber reinforced plastic sleeve as in Example 1, and the contracted tube was brought into contact with the PET film of sheet-like resin. The contact portion was bonded linearly by moving the laser head of a semiconductor laser welding apparatus (“FD-200”, manufactured by Fine Device Co., Ltd.) in the long axis direction of the hollow cylindrical support. The wavelength of the semiconductor laser used was 940 nm, the beam diameter was 3 mm, the average output was 50 W, and the beam diameter at the focal point was 1 mm. Next, the welding position was moved, the entire sheet-shaped resin cured product was welded at a pitch of 5 mm, and both ends were finally welded. The light transmittance of the sheet-like resin at a wavelength of 940 nm was 95% or more.

(Example 5)
[Production of heat-shrinkable tube]
Polyethylene terephthalate (manufactured by Unitika Ltd.) and phthalocyanine (manufactured by Nippon Shokubai Co., Ltd., “EEX Color (registered trademark) IR906”) at a ratio of 1 mass% using a kneader (manufactured by Moriyama Co., “D1-5”). Mix with heating to ° C. After cooling, it was pulverized, melted with a biaxial extruder (“KZW-TW”, manufactured by Technobel), extruded from a die, formed into a film shape, and then biaxially stretched to a thickness of 50 μm. Both ends were overlapped by about 3 mm so as to have a diameter about 1 mm larger than the outer diameter of the glass fiber reinforced plastic sleeve, which is a hollow cylindrical support to be used, to form a tube. A part of the heat-shrinkable tube was cut and used for measuring the heat shrinkage rate. As a result, the heat shrinkage rate at 80 ° C. was 30%.
Further, the centerline average surface roughness Ra of the heat-shrinkable tube was 0.2 μm, and the light transmittance was less than 1% in the laser light having an oscillation wavelength of 940 nm.
[Coating on cylindrical support (a)]
A glass fiber reinforced plastic sleeve (made by Polybest, Germany) with an inner diameter of 225 mm, a thickness of 1 mm, and a width of 200 mm mounted on an air cylinder is covered with the produced heat-shrinkable tube and contracted by heating to 120 ° C. And was brought into close contact with the hollow cylindrical support. The centerline average surface roughness Ra of the glass fiber reinforced plastic sleeve used was 1 μm.
[Preparation of cylindrical printing original plate]
Thereafter, in the same manner as in Example 3, a cylindrical printing original plate was produced. The outer diameter accuracy was ± 20 μm.
Thereafter, using a carbon dioxide laser engraving machine, a concavo-convex pattern was formed on the surface to prepare a cylindrical printing plate. As in Example 3, the dry offset printing plate was used for curved surface printing on the surface of an aluminum can. There was no problem with the durability of the cylindrical printing plate.

(Comparative Example 1)
The sheet resin produced in Example 1 was wrapped around the hollow cylindrical support used in Example 1 without covering the heat-shrinkable tube, and tapes were attached and fixed to both ends of the sheet-like resin. Unevenness was visually observed on the obtained surface, such as a hand touching the uncured resin portion. Then, the light of the metal halide lamp (the Fusion company make, "F450V type UV lamp") was exposed on condition of 8000 mJ / cm < ² > in 350 nm, and the cylindrical printing original plate was obtained.
Voids were observed in some places between the hollow cylindrical support of the obtained cylindrical printing original plate and the sheet-like photosensitive resin cured product. The outer diameter accuracy of the cylindrical printing original plate was ± 80 μm.
The obtained cylindrical printing original plate was laser engraved to form an image pattern on the surface, and then dry offset printing was performed in the same manner as in Example 1. However, due to the unevenness of the surface, printing defects corresponding to the unevenness occurred.

INDUSTRIAL APPLICABILITY The present invention is suitable as a method for producing a laser engraved cylindrical printing original plate for forming a pattern on the surface by a laser engraving method with high thickness accuracy and high productivity.
The present invention has industrial applicability as a printing plate in printing methods such as flexographic printing, dry offset printing, and gravure printing.

Claims (18)

A method for producing a cylindrical printing original for laser engraving,
(1) A step of coating the cylindrical support (a) with a heat-shrinkable tube having laser light absorption;
(2) heating and shrinking the heat-shrinkable tube;
(3) coating the sheet-like resin on the contracted tube;
(4) contacting the sheet-like resin with the contracted tube surface;
(5) irradiating the contacted part with laser light (α) and adhering it,
A method for producing a cylindrical printing original plate for laser engraving, wherein the sheet-like resin comprises at least one material selected from the group consisting of a thermoplastic resin, a photosensitive resin composition, and a thermosetting resin composition.   The manufacturing method according to claim 1, wherein the step (5) is a step of irradiating the interface where the sheet-like resin and the contracted tube are in contact with each other while focusing the laser light (α).   The manufacturing method of Claim 1 or 2 whose light transmittance of the said sheet-like resin is 50% or more and 100% or less in the oscillation wavelength of the said laser beam ((alpha)).   The manufacturing method of any one of Claim 1 to 3 whose oscillation wavelength of the said laser beam ((alpha)) is 700 nm or more and 3 micrometers or less. The laser beam (α) is
A continuous wave laser, or a pulsed laser whose laser pulse has a half-value duration of 1 nanosecond to 50 milliseconds,
The manufacturing method of any one of Claim 1 to 4 whose average output of the said laser beam ((alpha)) is 0.01W or more and 200W or less.   The manufacturing method according to any one of claims 1 to 5, wherein a beam diameter of the laser beam (α) at a focal portion is 1 µm or more and 5 mm or less.   The manufacturing method of any one of Claim 1 to 6 whose light transmittance of the said heat-shrinkable tube is 10% or less in the oscillation wavelength of the said laser beam ((alpha)) to be used.   The manufacturing method according to any one of claims 1 to 7, wherein the heat-shrinkable tube contains a dye or a pigment that absorbs near infrared rays.   The manufacturing method of any one of Claim 1 to 8 whose thickness of the said heat-shrinkable tube is 10 micrometers or more and 500 micrometers or less.   The manufacturing method of any one of Claim 1 to 9 whose centerline average surface roughness Ra of the said heat-shrinkable tube is 0.5 micrometer or less.   The photosensitive resin composition or the thermosetting resin composition is polyamide, polyimide, polyurethane, polyester, polycarbonate, polyether polyol, polyvinyl alcohol, vinyl alcohol-vinyl acetate copolymer, styrene-butadiene copolymer, and styrene. The production method according to any one of claims 1 to 10, comprising at least one resin selected from the group consisting of -isoprene copolymers.   The cylindrical support (a) includes a fiber reinforced plastic, and the fiber reinforced plastic includes glass fiber, polyamide fiber, polyimide fiber, polyester fiber, polyurethane fiber, cellulose fiber, carbon fiber, metal fiber, and ceramic fiber. The manufacturing method of any one of Claim 1 to 11 containing the at least 1 sort (s) of fiber selected from a group.   The said cylindrical support body (a) is a hollow cylindrical support body, The thickness of this hollow cylindrical support body is 0.2 mm or more and 2 mm or less, Any one of Claim 1-12. Production method.   A photosensitive resin composition or a thermosetting resin composition having a thickness of 50 μm or more and 5 mm or less on a sheet-like support made of a thermoplastic resin having a thickness of 10 μm or more and 500 μm or less. Or the manufacturing method of any one of Claim 1 to 13 which is a laminated body on which those hardened | cured material is laminated | stacked.   A cylinder for laser engraving, comprising the step of irradiating a laser beam (β) to form a concave pattern on the cylindrical printing original plate for laser engraving manufactured by the manufacturing method according to claim 1. A method for producing a printing plate.   The method for producing a cylindrical printing plate for laser engraving according to claim 15, wherein the cylindrical printing plate for laser engraving is a flexographic printing plate, a dry offset printing plate, or a gravure printing plate.   The dry offset printing method which prints on the cylindrical to-be-printed body surface using the dry offset printing plate manufactured by the manufacturing method of Claim 16.   The dry offset printing method according to claim 17, wherein printing is performed using an ink containing an aliphatic hydrocarbon and / or an aromatic hydrocarbon.