JP2009190333A - Resin composition for laser carved original printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition with excellent heat decomposability which is best-suited for manufacturing an original printing plate and a printing plate having an excellent suppressing effect on tailings to be generated during laser carving. <P>SOLUTION: The resin composition for a laser carved original printing plate includes a resin (a) which has a siloxane bond in the side chain, and has a number-average molecular weight of not less than 500 to not more than 300,000 and a heat polymerization initiator (c). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin composition for a laser engraving printing original plate containing a novel resin, a printing original plate obtainable by curing the resin composition, a method for producing the printing original plate, and the printing original plate subjected to laser engraving. Concerning the printing plate.

In recent years, flexographic printing has been widely used as a method for printing on soft packaging such as paper and film.
Flexographic printing used for packaging materials such as cardboard, paper containers, paper bags, flexible packaging films, wallpaper materials, decorative materials such as decorative boards, and label printing has increased its specific gravity among various printing methods. For the production of a printing plate used for this, a photosensitive resin is usually used in many cases, and a liquid resin or a solid resin plate formed into a sheet shape is used. A method has been used in which a photomask is placed on a photosensitive resin, light is irradiated through the mask to cause a crosslinking reaction, and then a non-crosslinked portion is washed away with a developer. In recent years, a thin light absorption layer called a black layer is provided on the surface of a photosensitive resin, and a laser beam is irradiated on the thin light absorption layer to form a mask image directly on the photosensitive resin plate. A so-called flexo CTP (Computer to Plate) technology has been developed to irradiate light through the mask to cause a crosslinking reaction, and then wash away the non-crosslinked portion of the light non-irradiated portion with a developer, thereby improving the efficiency of printing plate production. Adoption is progressing from the effect. However, this technique also has a limited efficiency improvement effect such as the development process remaining, and development of a technique that directly forms a relief image on a printing original plate using a laser and does not require development is required. .

As the method, a method of engraving a printing original plate directly with a laser can be mentioned. As a printing plate material for relief printing represented by flexographic printing, there is a laser engraving plate. There are advantages such as shortening of plate making time and reduction of waste.
Under such circumstances, in Patent Document 1, silicone oil is added to the resin composition for laser engraving printing original plate.
In Patent Document 2, a compound that converts laser light into heat, a polymer compound having film-forming ability, a photothermal exchange layer containing a photopolymerization initiator and an ethylenically unsaturated monomer, and a silicone rubber layer are laminated in this order. And a laser-sensitive dampening solution-free lithographic printing original plate characterized by reacting the photothermal conversion layer and the silicone rubber layer by performing overall exposure with energy rays after the formation of the silicone rubber layer
JP 2004-160898 A JP 09-146264 A

However, the fact is that no known laser-engraved printing plate is sufficiently excellent in laser engraving. Laser engraving means the ease of removal of residue when a resin is burned off with a laser.
However, in a printing plate engraved with laser, it is not yet known that the generation of liquid and / or solid engraving residue generated when forming irregularities with a laser on the printing original plate surface is sufficiently suppressed. Is the actual situation.
The technique disclosed in Patent Document 1 adds silicone oil as a component of a resin composition, and does not introduce a siloxane bond into a side chain in the resin. In addition, when the amount of silicone oil added is increased, there is a problem in that separation occurs without being uniformly mixed with other components.
The invention disclosed in Patent Document 2 is a dampening water-free lithographic printing original plate obtained by further laminating a silicone rubber layer on a photothermal conversion layer, which is different from the introduction of a siloxane bond into a side chain in a resin. There is no description about sculpture.
That is, the present invention provides a resin composition containing a novel resin having a specific structure, and further provides a laser-engravable printing original plate and printing plate that are extremely excellent in laser engraving performance by using the resin composition. For the purpose.

  As a result of intensive studies on the resin in order to solve the above problems, the present inventors have found that a heat containing a resin in which a siloxane bond is introduced into a side chain, which has been difficult to introduce in the past due to phase separation from other components. It has been found that by using a resin composition excellent in decomposability, a printing original plate and a printing plate having an excellent engraving residue generation suppressing effect during laser engraving can be obtained, and the present invention has been completed.

That is, the present invention is as follows.
1. A resin composition for a laser engraving printing original plate containing a resin (a) having a siloxane bond in a side chain and having a number average molecular weight of 500 to 300,000 and a thermal polymerization initiator (c).
2. The resin composition for a laser engraving printing original plate according to claim 1, wherein the resin (a) has a polymerizable unsaturated group.
3. The resin composition for a laser engraving printing original plate according to claim 1 or 2, wherein the resin composition further contains an organic compound (b) having a polymerizable unsaturated group and a number average molecular weight of less than 1000.
4). The resin composition for a laser engraving printing original plate according to any one of claims 1 to 3, wherein the number average molecular weight of the repeating unit having a siloxane bond contained in the resin (a) is 1000 or more and 30,000 or less.
5. 5. The resin composition for a laser engraving printing original plate according to claim 1, wherein the number average molecular weight of the repeating unit having a siloxane bond contained in the resin (a) is 10,000 or more and 20,000 or less.
6). 6. The laser engraving printing original plate according to claim 1, wherein the resin (a) is a resin having at least one chemical bond selected from the group consisting of a carbonate bond, a urethane bond, and an ester bond. Resin composition.
7. The resin composition for laser engraving printing original plate according to any one of claims 3 to 6, wherein 20% by mass or more of the total amount of the organic compound (b) is an alicyclic derivative and / or an aromatic derivative.
8. The resin composition for a laser engraving printing original plate according to any one of claims 1 to 7, which is liquid at 20 ° C.
9. The inorganic fine particles having a number average particle diameter of 0.01 μm or more and 10 μm or less further include 1 to 100 parts by mass with respect to 100 parts by mass of the resin composition for laser engraving printing original plate. The resin composition for laser engraving printing original plate as described in Item 1.
10. A step of forming the laser engraving printing precursor resin composition according to any one of claims 1 to 9 on a support in a sheet shape or a cylindrical shape, a method of irradiating the formed resin composition with heat rays, hot air A method for producing a laser engraving printing original plate comprising: a method of spraying, a method of exposing to an atmosphere in which hot air is convected, and a step of curing by at least one method selected from the group consisting of a method of contacting with a heated roll.
11. A laser engraving printing original plate obtainable by curing the resin composition for a laser engraving printing original plate according to claim 1.
12 The laser engraving printing original plate according to claim 11, further comprising a support on the non-printing surface side of the laser engraving printing original plate.
13. The laser engraving printing original plate according to claim 12, wherein the support is a hollow cylindrical support.
14 The laser engraving printing original plate according to claim 12 or 13, further comprising one or more cushion layers between the laser engraving printing original plate and the support.
15. The laser engraving printing original plate according to claim 14, wherein the cushion layer includes hollow microcapsules.
16. The laser engraving printing original plate according to any one of claims 13 to 15, further comprising one or more circumferential length adjusting layers between the laser engraving printing original plate and the hollow cylindrical support.
17. The laser engraving printing original plate according to any one of claims 11 to 16, wherein the outermost surface of the laser engraving printing original plate is surface-adjusted by at least one method selected from cutting, grinding, and polishing.
18. A printing plate obtained by laser engraving the printing original plate according to any one of claims 11 to 17.

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.
[Resin composition]
The resin composition needs to contain a resin (a) and a thermal polymerization initiator (c), and can be used for producing a printing original plate and a printing plate.
The resin composition is not particularly limited, but preferably contains an organic compound (b) and / or inorganic fine particles in addition to the resin (a) and the thermal polymerization initiator (c) depending on the purpose and purpose. .
Furthermore, the resin composition may contain additives such as fluorine-containing monomers, petroleum waxes, monomers having hydrocarbon chains, polymerization inhibitors, ultraviolet absorbers, dyes, lubricants, surfactants, plasticizers, and fragrances. it can.

The resin composition is preferably liquid at 20 ° C. The term “liquid at 20 ° C.” as used herein means a polymer that has the property of being easily flow-variable and solidifying into a deformed shape by cooling. It is a term corresponding to an elastomer having the property of recovering to its original shape in a short time when it is deformed and external force is removed. Due to this property, when the resin composition is formed into a sheet or cylinder in order to obtain a printing original plate, good thickness accuracy and dimensional accuracy can be obtained.
The viscosity at 20 ° C. of the resin composition is preferably 10 Pa · s or more and 10 kPa · s or less at 20 ° C. More preferably, it is 50 Pa · s or more and 5 kPa · s or less. When the viscosity is 10 Pa · s or more, the mechanical strength of the printing plate to be produced is sufficient, and the shape can be easily held and processed even when it is formed into a cylindrical shape. If the viscosity is 10 kPa · s or less, it is easy to be deformed and processed easily without increasing the temperature. It is easy to form into a sheet-like or cylindrical printing plate and the process is simple. In particular, in order to obtain a printing plate with high thickness accuracy, the viscosity is preferably 100 Pa · s or more, more preferably 200 Pa · s so that the resin composition for laser engraving printing original plate does not cause a phenomenon such as sag due to gravity. As described above, more preferably 500 Pa · s or more.

[Resin (a)]
Resin (a) needs to contain a siloxane bond in the side chain.
[Siloxane bond]
The siloxane bond of this embodiment will be described.
A siloxane bond means a molecular structure in which silicon (Si) and oxygen (O) are alternately bonded.
Although the details regarding the mechanism relating to the resin composition of the present embodiment having an excellent engraving residue generation suppressing effect are not clear, when the siloxane bond bonded to the side chain in the resin is decomposed by a laser, the siloxane The inventor presumes that the engraving residue tends to become a solid in a unit including a bond.
Wherein, the side chain having a siloxane _{bond, R p Q r X s SiO} (4-p-r-s) containing a silicone compound represented by the following average compositional formula (1) / 2 (1)

In formula (1), R is substituted with a linear or branched alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group. An alkyl group having 1 to 30 carbon atoms (carbon number before substitution), an aryl group having 6 to 20 carbon atoms substituted with a halogen atom, an alkoxycarbonyl group having 2 to 30 carbon atoms, a carboxyl group, or a salt thereof. A monovalent group containing, a monovalent group containing a sulfo group or a salt thereof, and one or more hydrocarbon groups selected from the group consisting of a polyoxyalkylene group,
Q and X are each a hydrogen atom, a linear or branched alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group. A substituted alkyl group having 1 to 30 carbon atoms, an aryl group having 6 to 20 carbon atoms substituted with a halogen atom, an alkoxycarbonyl group having 2 to 30 carbon atoms, a monovalent group including a carboxyl group or a salt thereof, Represents one or more hydrocarbon groups selected from the group consisting of a monovalent group including a sulfo group or a salt thereof and a polyoxyalkylene group, and p, r and s are:
0 <p <4,
0 ≦ r <4,
0 ≦ s <4,
And (p + r + s) <4.

In the present embodiment, the resin (a) can be obtained from a compound having a siloxane bond for introducing the siloxane bond into the side chain.
Examples of the compound having a siloxane bond for introducing a siloxane bond into the side chain include silicone oil. Silicone oils include low to high viscosity organopolysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, dimethylsiloxane / methylphenylsiloxane copolymer, octamethylcyclotetrasiloxane, decamethylcyclopenta Cyclic siloxanes such as siloxane, dodecamethylcyclohexasiloxane, tetramethyltetrahydrogencyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, etc., high degree of polymerization of gum-like dimethylpolysiloxane, gum-like dimethylsiloxane / methylphenylsiloxane copolymer Silicone rubber such as coalescence, and cyclic siloxane solution of silicone rubber, trimethylsiloxysilicic acid, trimethylsiloxysilicic acid cyclic siloxa Solution, higher alkoxy-modified silicones such as stearoxysilicone silicone, higher fatty acid-modified silicone.

  Of these, reactive silicone oil is preferred. Examples include monoamine modified silicone oil, diamine modified silicone oil, special amino modified silicone oil, epoxy modified silicone oil, alicyclic epoxy modified silicone oil, carbinol modified silicone oil, mercapto modified silicone oil, carboxyl modified silicone oil, hydrogen modified Silicone oil, amino / polyether modified silicone oil, epoxy / polyether modified silicone oil, epoxy / aralkyl modified silicone oil, reactive silicone oil silicone oil, methacrylic modified silicone oil, polyether modified silicone oil, mercapto modified silicone oil, phenol Modified silicone oil, silanol modified silicone oil, fluorine modified silicone oil, side chain Mino both ends methoxy-modified silicone oil, and diol-modified silicone oil. By using these reactive silicone oils, it is easy to introduce a siloxane bond into the resin (a).

Among the reactive silicone oils, one-end modified silicone oil and side chain modified silicone oil are preferable. For example, one-end diol modified silicone oil, side chain monoamine modified silicone oil, side chain diamine modified silicone oil, side chain epoxy modified silicone oil, side chain carbinol modified silicone oil, side chain carboxy modified silicone oil, side chain amino-polyether Modified silicone oil, side chain epoxy polyether modified silicone oil, side chain epoxy / aralkyl modified silicone oil, and the like.
Use of these one-end and side-chain silicone oils facilitates the introduction of siloxane bonds into the side chain of the resin (a), and also has a reactive functional group at the end, making it easy to adjust the molecular weight. It becomes. Among these, one-end diol-modified silicone oil is preferable from the viewpoint of high reactivity and handling properties such as easy introduction of a siloxane bond into the side chain. The molecular weight of the compound having a siloxane bond for introducing a siloxane bond into the side chain of the resin is preferably 1000 or more and 30,000 or less, more preferably 10,000 or more and 20,000 or less. If it is this range, the decomposability | degradability by the siloxane bond of a side chain will fully be exhibited, and since the fluidity | liquidity of this silicone compound can be ensured, handling is easy.

The resin (a) is a resin having a number average molecular weight of 500 to 300,000, preferably 2,000 to 250,000, more preferably 3,000 to 200,000.
When the number average molecular weight is 500 or more, the strength of the printing original plate and the printing plate is improved, so that it tends to withstand repeated use. On the other hand, if it is 300,000 or less, the viscosity at the time of molding of the resin composition does not increase excessively, so that the printing original plate and the printing plate tend to be more easily produced. The number average molecular weight referred to here is a value measured by gel permeation chromatography, calibrated with polystyrene having a known molecular weight, and converted.
The resin (a) may not necessarily have a polymerizable unsaturated group in the molecule, for example, when cured by heat, but preferably has a polymerizable unsaturated group in the molecule. It is preferable to have 0.3 or more polymerizable unsaturated groups on an average per molecule. When it has an average of 0.3 or more polymerizable unsaturated groups per molecule, it is preferable because the mechanical strength of the printing original plate and the printing plate is improved and the durability tends to be good. In consideration of the mechanical strength of the printing original plate and the printing plate, the number of polymerizable unsaturated groups in the resin (a) is more preferably 0.5 or more, more preferably 0.7 or more per molecule. The number of polymerizable unsaturated groups in the resin (a) is 2 or less per molecule from the viewpoint of improving the mechanical properties of the cured resin and simplifying the process of adding polymerizable unsaturated groups. preferable. Here, the “polymerizable unsaturated group” means a polymerizable functional group involved in radical polymerization reaction or addition polymerization reaction. The position of the polymerizable unsaturated group is preferably directly bonded to the polymer main chain, the end of the polymer side chain, or the polymer main chain or side chain. The average number of polymerizable unsaturated groups contained in one molecule of the resin (a) can be determined by a molecular structure analysis method using a nuclear magnetic resonance spectrum method (NMR method).

Furthermore, the resin (a) preferably has at least one chemical bond selected from the group consisting of a carbonate bond, a urethane bond, and an ester bond in the molecule. When the resin (a) has the chemical bond, the resistance of the printing original plate and the printing plate to an ink cleaning agent containing an ester solvent used in printing or an ink cleaning agent containing a hydrocarbon solvent tends to be improved. Therefore, it is preferable.
The method for producing the resin (a) is not particularly limited as long as it is obtained by reacting a compound having a siloxane bond, and has, for example, a carbonate bond, an ester bond, and a hydroxyl group, an amino group, an epoxy. The above reaction with a compound having a molecular weight of about several thousand having a plurality of reactive groups such as a group, a carboxyl group, an acid anhydride group, a ketone group, a hydrazine residue, an isocyanate group, an isothiocyanate group, a cyclic carbonate group, and an alkoxycarbonyl group After reacting a compound having a plurality of functional groups that can be bonded to the functional group (for example, polyisocyanate having a hydroxyl group, an amino group, etc.), adjusting the molecular weight, converting the molecular end to a binding group, etc. Introducing a polymerizable unsaturated group at the terminal by reacting a functional group capable of reacting with a terminal bondable group with an organic compound having a polymerizable unsaturated group It can be used and a method.

  Examples of the compound having a carbonate bond used in the production of the resin (a) include aliphatic polycarbonates such as 4,6-polyalkylene carbonate diol, 8,9-polyalkylene carbonate diol, and 5,6-polyalkylene carbonate diol. A diol etc. can be mentioned. Moreover, you may use the aliphatic polycarbonate diol which has an aromatic type molecular structure in a molecule | numerator. The terminal hydroxyl group of these compounds is tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tetramethylxylene diisocyanate, xylene diisocyanate, naphthalene diisocyanate, trimethylhexamethylene diisocyanate, p-phenylene diisocyanate, cyclohexene. Diisocyanate compounds such as silylene diisocyanate, lysine diisocyanate, triphenylmethane diisocyanate, triphenylmethane triisocyanate, 1-methylbenzene-2,4,6-triisocyanate, naphthalene-1,3,7-triisocyanate, biphenyl-2, Tris such as 4,4'-triisocyanate By condensation reaction of the isocyanate compound, thereby introducing a urethane bond may be high molecular weight. Furthermore, a terminal hydroxyl group or isocyanate group can also be used for introducing a polymerizable unsaturated group.

  Examples of the compound having an ester bond used in the production of the resin (a) include adipic acid, phthalic acid, malonic acid, succinic acid, itaconic acid, oxalic acid, glutaric acid, pimelic acid, speric acid, azelanic acid, and sebacin. Dicarboxylic acid compounds such as acid, fumaric acid, isophthalic acid, terephthalic acid and the like, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1 , 6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, piconal, cyclopentanediol, cyclohexanediol, etc. Has a hydroxyl group Polyesters obtained a compound with condensation reaction, polyesters such as polycaprolactone and the like. By subjecting the diisocyanate compound to a condensation reaction with the terminal hydroxyl group or carboxyl group of these compounds, a urethane bond can be introduced and the molecular weight can be increased. Furthermore, a terminal hydroxyl group, carboxyl group or isocyanate group can also be used for introducing a polymerizable unsaturated group.

The resin (a) preferably contains a liquid resin having a glass transition temperature of 20 ° C. or lower, and preferably contains a liquid resin having a glass transition temperature of 0 ° C. or lower. Examples of such liquid resins include compounds having a hydrocarbon chain such as polyethylene, polybutadiene, hydrogenated polybutadiene, and polyisoprene, polyester compounds having an ester bond such as adipate and polycaprolactone, compounds having a polycarbonate structure, polydimethyl Examples thereof include a compound having a siloxane skeleton. In particular, unsaturated polyurethanes having a polycarbonate structure are more preferable from the viewpoint of weather resistance. Liquid resin here means a polymer that has the property of being easily deformed by flow and solidified into a deformed shape by cooling. When an external force is applied, the liquid resin is instantly deformed according to the external force. However, it is a term corresponding to an elastomer having the property of recovering its original shape in a short time when external force is removed.
The viscosity of the resin (a) at 20 ° C. is preferably 10 Pa · s to 10 kPa · s, more preferably 30 Pa · s to 7 kPa · s, and further preferably 50 Pa · s to 5 kPa · s. If the viscosity is 10 Pa · s or more, the mechanical strength tends to be good when it is used as a printing original plate. If the viscosity is 10 kPa · s or less, it is easily deformed even at room temperature and mixed with other compositions. It tends to be easy to form.

[Thermal polymerization initiator (c)]
As the thermal polymerization initiator (c) in the present embodiment, suitable compounds are all thermal polymerization initiators that can be used for 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. Moreover, it is preferable that the thermal polymerization initiator (c) of this Embodiment is a liquid state at 20 degreeC. Mixing with resin (a) becomes easy by being liquid.

The selection of a suitable thermal polymerization initiator (c) is particularly important in the present embodiment. The thermal stability of the thermal polymerization initiator (c) is usually determined by the method with a 10 hour half-life temperature of 10 h-t _1/2 , ie 50% of the initial amount of the thermal polymerization initiator (c) is 10%. It is shown at the temperature at which it decomposes after time to form free radicals. Further details on this are given in “Encyclopedia of Polymer Science and Engineering”, Vol. 11, page 1 onwards, John Wiley & Sons, New York, 1988.
The thermal polymerization initiator (c) particularly suitable for this embodiment usually has a 10 h-t _1/2 of at least 60 ° C., preferably at least 70 ° C. Particularly suitable thermal polymerization initiators (c) have 10 h-t _1/2 of 80 ° C to 150 ° C.

As the thermal polymerization initiator (c) of the present embodiment, an organic peroxide is particularly preferable. Specific examples of the compound include monoperoxycarbonates such as t-butylperoxy-2-ethylhexyl monocarbonate, peroxyesters such as t-butyl peroctanoate, t-amyl peroctanoate, and peroxyisobutyric acid. t-butyl, t-butyl peroxymaleate, t-amyl perbenzoate, di-t-butyl diperoxyphthalate, 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 Alkyl peroxides such as di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide 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. Moreover, an azo compound can be mentioned as a preferable thing when forming the layer which has a cushioning property containing a bubble. 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.
The addition amount of the thermal polymerization initiator (c) is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.3 parts by mass or more and 3 parts by mass with respect to 100 parts by mass of the resin (a). It is as follows. If the addition amount is within this range, the mechanical properties of the cured product can be sufficiently secured even when the resin composition is cured.

[Organic compound (b)]
The organic compound (b) is an organic compound having a polymerizable unsaturated group and having a number average molecular weight of less than 1000. The number average molecular weight is preferably less than 1000 from the viewpoint of easy dilution with the resin (a), and preferably 100 or more from the viewpoint of handling such as low volatility.
The definition of a polymerizable unsaturated group is a polymerizable unsaturated group that participates in a radical or addition polymerization reaction as described in the section of the resin (a).
In this Embodiment, content in particular of an organic compound (b) is although it does not restrict | limit, Preferably it is 20 mass parts or more and 300 mass parts or less with respect to 100 mass parts of resin (a), More preferably, it is 50 mass parts or more. It is 250 parts by mass or less. When the content of the organic compound (b) is 20 parts by mass or more, the printing original plate and the printing plate that are cured products of the resin composition tend to have sufficient mechanical strength, and are 300 parts by mass or less. The curing shrinkage of the printing original plate and the printing plate, which are cured products of the resin composition, tends to be reduced.

  Specific examples of the organic compound (b) include radical reactive compounds such as olefins such as ethylene, propylene, styrene and divinylbenzene, acetylenes, (meth) acrylic acid and derivatives thereof, haloolefins, acrylonitrile and the like. Saturated nitriles, (meth) acrylamide and derivatives thereof, aryl compounds such as aryl alcohol and aryl isocyanate, unsaturated dicarboxylic acids such as maleic anhydride, maleic acid and fumaric acid and derivatives thereof, vinyl acetates, N-vinylpyrrolidone, N-vinyl carbazole etc. are mentioned. (Meth) acrylic acid and its derivatives are preferable examples from the viewpoints of the abundance of the kind, price, decomposability upon laser light irradiation, and the like. Examples of the derivatives include alicyclic compounds having a cycloalkyl group, a bicycloalkyl group, a cycloalkene group, a bicycloalkene group, an aromatic compound having a benzyl group, a phenyl group, a phenoxy group, a fluorene group, an alkyl group, and a halogenated group. Examples include compounds having an alkyl group, an alkoxyalkyl group, a hydroxyalkyl group, an aminoalkyl group, a glycidyl group, and ester compounds with polyhydric alcohols such as alkylene glycol, polyoxyalkylene glycol, polyalkylene glycol, and trimethylolpropane. .

  As specific examples of the organic compound (b), the compound having an epoxy group that undergoes addition polymerization reaction includes compounds obtained by reacting various diols and polyols such as triol with epichlorohydrin, and a peracid for an ethylene bond in the molecule. An epoxy compound obtained by reacting can be mentioned. Specifically, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, tetraethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene Glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, bisphenol A diglycidyl ether, hydrogenated bisphenol A Diglycidyl ether, bisphenol A Diglycidyl ether, polytetramethylene glycol diglycidyl ether, poly (propylene glycol adipate) diol diglycidyl ether, poly (ethylene glycol adipate) diol diglycidyl ether, poly (caprolactone) diol diglycidyl Mention may be made of epoxy compounds such as ethers.

The organic compound (b) having a polymerizable unsaturated group can be selected from one or more types depending on the purpose. For example, when used as a printing plate, it has at least one long-chain aliphatic, alicyclic or aromatic derivative as an organic compound used to suppress swelling due to an organic solvent such as alcohol or ester which is a solvent for printing ink. It is preferable.
In order to increase the mechanical strength of the printing original plate obtained from the resin composition, the organic compound (b) preferably contains an alicyclic derivative and / or an aromatic derivative. In this case, the content of the alicyclic derivative and / or aromatic derivative is preferably 20% by mass or more, more preferably 50% by mass or more, based on the total amount of the organic compound (b). The aromatic derivative may be an aromatic compound having an element such as nitrogen or sulfur.

In order to increase the resilience of the printing plate, for example, a methacrylic monomer as described in JP-A-7-239548 can be used, and it can be selected by utilizing technical knowledge of known printing resins. .
The resin (a) and / or the organic compound (b) is a compound having at least one chemical bond selected from the group consisting of a carbonate bond, an ester bond, and an ether bond in the molecular chain, and / or aliphatic saturation. A compound having a hydrocarbon chain and having a urethane bond and / or a compound having an aliphatic unsaturated hydrocarbon chain and having a urethane bond is preferred in order to improve the solvent resistance of the printing plate. Among them, a compound having a carbonate bond, a compound having an aliphatic saturated hydrocarbon chain and a urethane bond, a compound having an aliphatic unsaturated hydrocarbon difference and a urethane bond are ester solvents that are frequently used in solvent inks. Shows particularly high solvent resistance.

[Additive]
In the present embodiment, examples of additives include fluorine-containing monomers, petroleum waxes, monomers having hydrocarbon chains, dyes, pigments, polymerization inhibitors, ultraviolet absorbers, lubricants, surfactants, plasticizers, and fragrances. Is mentioned.
Although the total addition amount of an additive is not restrict | limited in particular, It is preferable that it is 0.1 to 50 mass parts with respect to 100 mass parts of resin (a).
The fluorine-containing monomer is not particularly limited as long as it is a fluorine-containing monomer having a polymerizable functional group. Examples of the fluorine-containing monomer having a polymerizable functional group include a monomer having a double bond, a triple bond, an epoxy group, an oxetane skeleton, or a ketene acetal skeleton.

  Specifically, tetrafluoroethylene (hereinafter referred to as TFE), hexafluoropropylene (hereinafter referred to as HFP), vinylidene fluoride (hereinafter referred to as VdF), trifluoroethylene, 1,2-difluoroethylene, fluorine. Vinyl fluoride, trifluoropropylene, chlorotrifluoroethylene (hereinafter referred to as CTFE), 3,3,3-trifluoropropene, 2-trifluoromethyl-3,3,3-trifluoro-1-propene, perfluoro Linear or branched aliphatic fluoroolefins such as (butylethylene), perfluoro (methyl vinyl ether) (hereinafter referred to as PMVE), perfluoro (ethyl vinyl ether), perfluoro (propyl vinyl ether) (hereinafter, Perfluoro (PPVE)) Perfluoro (alkenyl vinyl ether) such as perfluoro (1,3-dioxole), perfluoro (butenyl vinyl ether) (hereinafter referred to as BVE), and perfluoro (2,2-dimethyl-1,3). -Dioxole) (hereinafter referred to as PDD), peroxyolefin-containing cyclic perfluoroolefins such as perfluoro- (2-methylene-4-methyl-1,3-dioxolane), (perfluorobutyl) ethyl acrylate, (Perfluorohexyl) ethyl acrylate (hereinafter referred to as FHA), (perfluoroheptyl) methyl acrylate, (perfluorooctyl) ethyl acrylate (hereinafter referred to as FOA) and the like (perfluoroalkyl) ethyl acrylate, (perfluorobutyl) ) Echi (Perfluoroalkyl) ethyl methacrylate such as methacrylate, (perfluorohexyl) ethyl methacrylate (hereinafter referred to as FHMA), (perfluoroheptyl) methyl methacrylate, (perfluorooctyl) ethyl methacrylate (hereinafter referred to as FOMA) , Α-fluorostyrene, β-fluorostyrene, α, β-difluorostyrene, β, β-difluorostyrene, α, β, β-trifluorostyrene, α-trifluoromethylstyrene, 2,4,6-tri ( Trifluoromethyl) styrene, 2,3,4,5,6-pentafluorostyrene, perfluoro (styrene), fluorostyrene such as 2,3,4,5,6-pentafluoro-α-methylstyrene, and the like. It is done. Among these, compounds having a long carbon chain such as perfluorooctyl methacrylate are preferable.

These fluorine-containing monomers may have a functional group other than the polymerizable functional group.
Petroleum waxes (paraffins) used in the present embodiment are roughly classified into n-paraffins having a linear hydrocarbon chain, isoparaffins having a branched chain, and cycloparaffins having a cyclic chain. Among these, those having a melting point of 65 ° C. or lower are preferred, and more preferably, the melting point is 60 ° C. or lower. If it is this range, when it adds in a resin composition, it will become the tendency for a wax to become a solid hard.
Examples of the monomer having a hydrocarbon chain used in the present embodiment include vinyl esters of aliphatic or aromatic carboxylic acids such as vinyl decanoate, vinyl stearate, and vinyl palmitate, allyl decanoate, allyl stearate, and palmitic acid. Aliphatic or aromatic allyl esters such as allyl acid, allyl stearate, and alkyl vinyl ethers such as vinyl ethyl ether and / or vinyl polyether.
By using the additives as described above, the printing plate tends to be difficult to stain with ink.
Examples of coloring methods for improving visibility include the use of dyes and pigments. Specific pigments include "HELIOGEN BLUE D 6700" (trade name, manufactured by BASF), "PALIOGEN RED K". 3580 "(trade name, manufactured by BASF) is preferable.

[Inorganic fine particles]
The inorganic fine particles in the present embodiment preferably have a number average particle size of 0.01 μm or more and 10 μm or less. If the number average particle size is in the above range, stickiness can be reduced in the cutting, grinding, and polishing processes, the surface roughness of the printing original plate is less affected, and patterns can be formed by laser engraving without causing defects in the printed image. is there. In addition, the inorganic fine particles in the present embodiment are preferably porous fine particles or nonporous ultra fine particles.
The porous fine particles in the present embodiment are defined as fine particles having fine pores having a pore volume of 0.1 ml / g or more in the particles, or fine particles having fine voids. By containing the porous fine particles, processing becomes easy when the surface of the printing layer is made to have a desired surface roughness. Examples of the processing include cutting, grinding, and polishing. The stickiness of debris and the like generated during processing when the desired surface roughness is obtained by the porous fine particles is reduced, and it becomes easy to precisely process the surface of the printing layer.

The porous fine particles have a specific surface area of 10 m ² / g to 1500 m ² / g, an average pore diameter of 1 nm to 1000 nm, a pore volume of 0.1 ml / g to 10 ml / g, and an oil absorption of 10 ml / 100 g to 2000 ml. / 100 g or less is preferable. The specific surface area is determined from the adsorption isotherm of nitrogen at −196 ° C. based on the BET equation. A nitrogen adsorption method is used to measure the pore volume and the average pore diameter. The oil absorption was measured according to JIS-K5101. When the specific surface area of the porous fine particles is within the above range, for example, when forming an image portion by engraving a printing original plate with a laser, it is suitable for absorbing the removed decomposition product.
The number average particle diameter of the porous fine particles is preferably 0.01 μm or more and 10 μm or less. More preferably, they are 0.5 micrometer or more and 8 micrometers or less, More preferably, they are 1 micrometer or more and 5 micrometers or less. If the number average particle size is in the above range, stickiness can be reduced in the cutting, grinding, and polishing processes, and there is little effect on the surface roughness of the printing original plate, allowing pattern formation by laser engraving without causing defects in the printed image. It is.
The shape of the porous fine particles is not particularly limited, and spherical, flat, acicular, amorphous, or particles having protrusions on the surface can be used. In particular, from the viewpoint of wear resistance, spherical particles having a sphericity of at least 70% in the range of 0.5 to 1 are preferable.

The sphericity is defined as a finger ring that defines the degree of sphericity of the porous fine particles. The sphericity in the present embodiment is the ratio of the maximum value D ₁ of the circle that completely enters the projected figure when the porous fine particles are projected to the minimum value D ₂ of the circle that completely enters the projected figure (D ₁ / D ₂ ). In the case of a true sphere, the sphericity is 1.0. The sphericity of the porous fine particles is preferably 0.5 or more and 1.0 or less, more preferably 0.7 or more and 1.0 or less. If it is 0.5 or more, the wear resistance as a printing plate is good. The sphericity of 1.0 is an upper limit value of sphericity. The porous fine particles preferably have a sphericity of 0.5 or more, preferably 70% or more, more preferably 90% or more. As a method of measuring the sphericity, a method of measuring based on a photograph taken using a scanning electron microscope can be used. At that time, it is preferable to take a picture at a magnification at which at least 100 particles enter the monitor screen. The D ₁ and D ₂ are measured on the basis of a photograph, but it is preferable to process the photograph using a digitizing device such as a scanner and then process the data using image analysis software.

Moreover, it is also possible to use spherical particles having a uniform pore diameter such as particles having hollow inside particles or silica sponge. Although not particularly limited, for example, porous silica, mesoporous silica, silica-zirconia porous gel, porous alumina, porous glass and the like can be mentioned. In addition, since pore diameters cannot be defined for those in which voids of several nanometers to several hundreds of nanometers exist between layers, such as layered clay compounds, the interval between voids existing between layers is defined as the pore diameter in this embodiment. Define.
Furthermore, the surface of the porous fine particles can be coated with a silane coupling agent, a titanium coupling agent, or other organic compounds, and subjected to a surface modification treatment to make the particles more hydrophilic or hydrophobic. These porous fine particles can be selected from one type or two or more types.
The nonporous ultrafine particles in the present embodiment are defined as particles having a pore volume of less than 0.1 ml / g. The number average particle diameter of the nonporous ultrafine particles is a number average particle diameter for primary particles, and is preferably 10 nm or more and 500 nm or less. More preferably, it is 10 nm or more and 100 nm or less. Within this range, stickiness can be reduced in the cutting, grinding, and polishing steps, the influence on the surface roughness of the printing original plate is small, and a pattern can be formed by laser engraving without causing defects in the printed image.

[Print master / print plate]
The printing original plate of this Embodiment is demonstrated.
The printing original plate of the present embodiment is not limited as long as it can be obtained by curing the resin composition. The printing original plate is formed, for example, by forming a resin composition containing a resin containing a siloxane bond in a side chain into a sheet shape or a cylindrical shape, irradiating the formed resin composition with heat rays, a method of blowing hot air, and hot air convection. There are those manufactured by a method including a step of curing by at least one method selected from the group consisting of a method of exposing to an atmosphere to be heated and a method of contacting with a heated roll. By obtaining a printing original plate by a heat curing step, it is easy to increase the thickness of the printing original plate as compared to the photocuring step. In particular, from the viewpoint of ease of workability, a method of irradiating with heat rays and a method of contacting with a heated roll are preferable. Examples of the heat rays include near infrared rays and infrared rays.

  There is no restriction | limiting in the method of shape | molding the resin composition of this Embodiment in a sheet form or a cylindrical form, The existing molding method of resin can be used. For example, a method of extruding a resin from a nozzle or a die with a machine such as a pump or an extruder and adjusting the thickness with a blade (casting method); a method of adjusting the thickness by calendaring with a roll can be exemplified. It is also possible to perform molding while heating within a range that does not deteriorate the performance of the resin. Moreover, you may perform a rolling process, a grinding process, etc. as needed. Usually, the resin composition is formed on an underlay called a back film made of a material such as PET (polyethylene terephthalate) or nickel, but it can also be formed directly on a cylinder of a printing press. In that case, a seamless seamless sleeve can be formed. Also, a sleeve molding / engraving apparatus (apparatus for applying a liquid resin composition on a cylindrical support and irradiating light to cure the resin composition by applying heat to cure the resin composition It is also possible to form a printing original plate using a laser light source for laser engraving incorporated therein. When such an apparatus is used, the printing plate can be formed by laser engraving immediately after forming the sleeve, so a short time that cannot be considered with a conventional rubber sleeve that required several weeks for the forming process. Time machining can be realized.

[Support]
The support used in the present embodiment is preferably a hollow cylindrical support, and the hollow cylindrical support is preferably made of reinforced plastic. Since the support is a hollow cylindrical shape, the support can be easily attached to and detached from the printing press, and since the support is cylindrical, the resin composition can be applied while rotating around the shaft. More uniform coating becomes possible. Further, since the hollow cylindrical support is made of reinforced plastic, the adhesive force with the adhesive layer can be maintained while maintaining the strength.
In the present embodiment, the reinforced plastic is a fiber reinforced plastic, and the fiber reinforced plastic is selected from an epoxy resin, a polyester resin, a polyimide resin, a polyurethane resin, a polyamide resin, a polyketone resin, a polysulfone resin, and a polyphenylene ether resin. It is preferable to contain at least one resin.

Moreover, the fiber formed from the inorganic compound can also be included. The fiber is not particularly limited, but polyester fiber, polyamide fiber, polyurethane fiber, polyimide fiber, polypropylene fiber, polyethylene fiber, polyacrylonitrile fiber, polyphenylene ether fiber, polyvinyl alcohol fiber, phenol fiber, fluororesin fiber, polyether ether ketone Examples thereof include resins, vinylidene fibers, poly-p-phenylenebisoxazole fibers, polyphenylene sulfide fibers, polyclar fibers, polyketone fibers, and synthetic pulp fibers. Preferred examples of short fibers formed from natural organic compounds include bast fibers, vein fibers, and plant fibers such as cellulose.
Moreover, the fiber formed from the inorganic compound can also be included. Preferred examples include glass, carbon, silicon nitride, boron nitride, silicon carbide, alumina, nickel, titanium, copper, iron, tungsten, and chromium.

[Cushion layer]
The cushion layer is not particularly limited, and any cushion layer having rubber elasticity can be used. Examples thereof include natural rubber materials, synthetic rubber materials such as SBR, SBS, and SIS, soft plastic materials such as silicone rubber, urethane rubber, butyl rubber, fluorine rubber, and polyethylene. Moreover, the sheet-like elastomer formed by photocuring the resin composition can also be used. Among these materials, in particular, a sheet material mainly composed of polyethylene or polyurethane used for printing can be cited as a preferable material. It is convenient to use a commercially available cushion tape for flexographic printing. The cushion layer preferably has a thickness of 0.10 mm to 6.00 mm. More preferably, it is 0.20 mm or more and 2.00 mm or less, More preferably, it is 0.30 mm or more and 0.70 mm or less. The specific gravity of the cushion layer is preferably 0.20 g / cm ³ or more and 0.90 g / cm ³ or less. More preferably, it is 0.30 g / cm ³ or more and 0.70 g / cm ³ or less, and further preferably 0.40 g / cm ³ or more and 0.60 g / cm ³ or less. The ASKER-C hardness of the cushion layer is preferably 30 or more and 90 or less.

Moreover, by using an adhesive layer for the adhesive layer, the cushion layer is peeled off from the cylindrical support after the cylindrical cushion is used, and the cylindrical support can be easily used again.
In the present embodiment, the cushion layer preferably further includes fine particles having a number average particle diameter of 0.1 μm or more and 200 μm or less. As such fine particles, inorganic fine particles, organic fine particles, hollow capsule-shaped fine particles and the like can be used. By containing the fine particles, the thixotropy is improved, so that the application of the resin composition for a laser engraving printing original plate to the support tends to be easy.
The number average particle diameter of the fine particles is from 0.1 μm to 200 μm, more preferably from 0.5 μm to 150 μm, and even more preferably from 1.0 μm to 100 μm. Here, the number average particle diameter of the fine particles refers to an average value of the major axis values measured by microscopic observation. Specifically, the magnification is adjusted so that at least about 50 fine particles or bubbles enter the visual field of the microscope, and the major axis of the fine particles or bubbles is measured. Although it is preferable to use a microscope having a length measuring function, the dimensions may be measured based on a photograph taken using a camera.

Here, examples of the inorganic fine particles include silica, alumina, calcium carbonate, zeolite, magnesium hydroxide, zirconium silicate and the like. The average particle size of the inorganic fine particles is preferably 10 nm to 30 μm, more preferably 0.1 μm to 20 μm, and still more preferably 0.5 μm to 10 μm.
As the organic fine particles, fine particles having at least one kind of skeleton selected from a polysiloxane skeleton, a polystyrene skeleton, a poly (meth) acrylate skeleton, a polyurethane skeleton, and a polyacrylonitrile skeleton have mechanical strength and solvent resistance. It is preferable from the viewpoint of balancing. Examples of such organic fine particles include silicone rubber, crosslinked acrylic acid fine particles, crosslinked acrylic acid porous fine particles, and crosslinked polystyrene.

The hollow capsule-shaped fine particles are fine particles having a composite composition of 1 μm to several hundred μm, which have different compositions between the outer shell and the inner core. The method for producing the hollow capsule is roughly divided into an interfacial polymerization method, a coacervation method, an interfacial precipitation method, and a submerged drying method. In principle, the atomized core material is dispersed in a suitable medium and then coated with a film of fine particles. As a conventional method for producing a hollow microcapsule, there is a method of producing a microcapsule enclosing a liquid and evaporating the liquid inside to make it hollow, or a method of producing a similar microcapsule by thermal expansion. .
As the hollow capsule-shaped fine particles, inorganic fine particles may be attached to the surface of the hollow capsule-shaped organic fine particles. Due to the presence of inorganic fine particles on the surface, the solubility in the resin composition for laser engraving printing original plate is lowered, and it can be stably present in the resin composition for laser engraving printing original plate for a long time. The average particle size of the inorganic fine particles present on the surface is preferably 10 nm or more and 30 μm or less, more preferably 0.1 μm or more and 20 μm or less, and further preferably 0.5 μm or more and 10 μm or less. Examples of the material of the inorganic fine particles present on the surface include silica, alumina, calcium carbonate, zeolite, magnesium hydroxide, zirconium silicate and the like.

[Perimeter adjustment layer]
It is preferable that the thickness of the circumferential length adjusting layer of the present embodiment can be arbitrarily changed according to the repeat length for printing with a printing press. The resin composition that can be used may be a solid resin composition at 20 ° C., but a liquid resin composition is particularly preferable from the viewpoint of arbitrarily changing the thickness of the circumference adjusting layer. . A solvent may be contained in the liquid resin composition, but since a solvent removal step is required, a solventless liquid resin composition is more preferable. When the liquid resin composition is used, a seamless layer having a uniform film thickness can be formed. The preferred viscosity of the liquid resin composition is 10 Pa · s or more and 10 kPa · s or less, more preferably 500 Pa · s or more and 5 kPa · s or less at 20 ° C. In order to form a thick film, dripping may occur due to gravity and the film thickness may change, so the viscosity range as described above is preferable. Further, when the film thickness to be molded is very thin, it is desirable to keep the viscosity low. As a method of reducing the viscosity, a method of adding a solvent can also be used as a simple method.

[Cutting / Grinding / Polishing]
When processing the surface, it is preferable to adjust the surface by at least one method selected from cutting, grinding, and polishing. Although it is possible to process the surface using only the cutting process, it is preferable to perform the polishing process after the cutting process or the grinding process because the surface shape of the printing original plate can be adjusted more precisely.
Processing by cutting the surface of the printing original plate is not particularly limited, and examples thereof include processing with a blade such as a lathe, a drilling machine, a milling machine, a shaper, a planer, and an NC machine tool.

Examples of the processing by grinding the surface of the printing original plate include processing by a grindstone. The material of the grinding wheel used for grinding is not particularly limited, but examples thereof include alumina-based and silicon carbide-based materials. Examples of the material of the grindstone include brown alumina, white alumina, light red alumina, and pulverized alumina in the case of alumina, and black silicon carbide and green silicon carbide in the case of silicon carbide.
Regarding the particle size of the abrasive grains of the grinding wheel used for grinding, a grinding wheel of 8 or more and 5000 or less is preferably used. Examples of the main component of the binder for bonding abrasive grains include feldspar soluble viscosity / flux, bakelite artificial resin, sodium silicate flux, natural / artificial rubber / sulfur, shellac natural resin, metal foil, and the like.
The polishing body used for polishing the surface of the printing original plate is not particularly limited, and examples thereof include polishing films such as polishing paper, wrapping films, and mirror films, and polishing wheels.

  As a material for the abrasive on the surface of the abrasive paper or the abrasive film, at least one kind of fine particles selected from metals, ceramics, and carbon compounds is preferable. As an example of the metal fine particles, a relatively hard material such as chromium, titanium, nickel, and iron is preferable. Specific examples of ceramics include alumina, silica, silicon nitride, boron nitride, zirconia, zirconium silicate, silicon carbide, and the like. Examples of the material quality of the alumina abrasive grains include brown alumina, pulverized alumina abrasive, light red alumina abrasive, white alumina abrasive, and artificial emery abrasive. Examples of the material quality of the silicon carbide abrasive grains include a black silicon carbide abrasive and a green silicon carbide abrasive. Examples of the carbon compound include compounds such as diamond and graphite. In particular, artificial diamond is preferable as an abrasive. Other abrasive materials include glass-based abrasives such as glass beads, resin-based abrasives such as nylon, polycarbonate, polyester, and methyl metal acrylate, and plant-based abrasives such as walnut shell, apricot seed, and peach seed. Can also be used. Furthermore, it is also possible to use a polishing cloth in combination with the above abrasive.

The number average particle size of the abrasive is preferably from 0.1 μm to 100 μm. More preferably, it is 3 μm or more and 100 μm or less. More preferably, the particle size is 9 μm or more and 30 μm or less. If it is in the range of 100 μm or less, a printing original plate that can be suitably used for printing evaluation can be easily prepared.
In particular, the average particle diameter of the abrasive is preferably 20 μm or less from the viewpoint of improving the ink transfer property to the printing medium and the printing quality by reducing the unevenness of the surface of the obtained printing original plate. On the other hand, from the viewpoint of shortening the time required for surface processing and improving the productivity of the printing original plate, the average particle diameter of the abrasive is preferably 12 μm or less.

As the particle size of the grinding wheel surface, 60 to 3000 is preferably used. The material of the polishing wheel is not particularly limited, and examples thereof include iron, alumina, ceramics, carbon compound, grindstone, wood, brush, felt, cork and the like.
The thickness and material of the support such as abrasive paper or abrasive film are not particularly limited, but the thickness is preferably in the range of 1 μm to 1000 μm. More preferably, they are 10 micrometers or more and 500 micrometers, More preferably, they are 25 micrometers-125 micrometers. If it is in the range of 25 μm or more and 125 μm or less, handling such as winding is easy. The shape of the support is not particularly limited, and examples thereof include rolls, disks, sheets, and belts.

In addition, it is possible to polish the printing original plate surface even with dry polishing without interposing liquid when polishing using the polishing body, but the polishing power, uniformity of the printing original plate surface after polishing, less dust generation, polishing In consideration of the removal of heat generated inside, it is preferable to bring the abrasive into contact with the printing original plate while interposing a liquid. Although it does not specifically limit as a liquid to be used, For example, petroleum, machine oil, an alkaline solution, water etc. are mentioned.
In particular, when water is used as a liquid to be interposed during polishing, the printing original plate is less denatured than when other liquids are used, and the waste liquid can be easily treated.
As another preferable aspect of the surface adjustment of the present embodiment, fine particles having an average particle diameter of at least about 0.1 μm and not more than 100 μm made of at least one substance selected from metals, ceramics, carbon compounds and the like are formed on the surface of the printing original plate. The method of making it collide is also mentioned.
The method for causing the fine particles to collide with the printing original plate is not particularly limited, and examples thereof include sand blast, shot blast, air blast, blower blast and the like. The material of the fine particles is not particularly limited. For example, glass particles such as glass beads, resin particles such as nylon, polycarbonate, polyester, and methyl metal acrylate, walnut shell, apricot seed, and peach seed. And plant-based particles.

[Laser engraving]
In laser engraving, an image to be formed is converted into digital data, and a relief image is created on an original by operating a laser device using a computer. Any laser may be used for the laser engraving as long as the original includes a wavelength having absorption. In order to carry out engraving at a high speed, one having a high output is desirable, and a laser having an oscillation wavelength in the infrared or near infrared region such as a carbon dioxide laser, a YAG laser, a semiconductor laser, or a fiber laser is preferable. In addition, an ultraviolet laser having an oscillation wavelength in the ultraviolet region, such as an excimer laser, a YAG laser wavelength-converted to the third or fourth harmonic, a copper vapor laser, and the like, can be ablated to cut bonds between organic molecules, Suitable for fine processing. A laser having a very high peak output such as a femtosecond laser can also be used. The laser may be continuous irradiation or pulse irradiation. In general, a resin has absorption at a wavelength in the vicinity of 10 μm. Therefore, when a carbon dioxide laser having an oscillation wavelength in the vicinity of 10 μm is used, it is not particularly necessary to add a component that helps absorption of the laser beam. However, YAG lasers, semiconductor lasers, and fiber lasers have an oscillation wavelength in the vicinity of 1 μm, but since there are not many organic substances that absorb light in this wavelength region, it is necessary to add dyes and pigments that are components that assist in light absorption. .

Examples of such dyes include poly (substituted) phthalocyanine compounds and metal-containing phthalocyanine compounds; cyanine compounds; squarylium dyes; chalcogenopyrroloarylidene dyes; chloronium dyes; metal thiolate dyes; Examples include lysine dyes; bis (aminoaryl) polymethine dyes; merocyanine dyes and quinoid dyes. Examples of pigments include dark inorganic pigments such as carbon black, graphite, copper chromite, chromium oxide, cobalt chrome aluminate, iron oxide, and metal powders such as iron, aluminum, copper, and zinc, and Si, Examples include those doped with Mg, P, Co, Ni, Y, and the like. These dyes and pigments may be used alone, in combination of a plurality, or in any form such as a multilayer structure.
Laser engraving 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, the powdery or liquid substance slightly generated on the relief printing plate surface is irradiated with an aqueous cleaning agent by an appropriate method, for example, a method of washing with water containing a solvent or a surfactant, or a high-pressure spray. You may remove using the method, the method of irradiating a high pressure steam, etc.

[Printed version]
The printing plate in the present embodiment is a printing plate obtained by laser engraving a printing pattern on the surface of a printing original plate.
There is no limitation on the form of the printing plate of this embodiment, and it can be used as any printing plate such as a flexographic plate, a resin relief plate, or a blanket used for offset, dry offset, reversal offset or gravure offset. Preferably used.

Hereinafter, the present embodiment will be described in detail with reference to production examples, examples, and comparative examples. In the following, “parts” and “%” mean “parts by mass” and “% by mass”, respectively.
(1) Measurement of viscosity The viscosity of the liquid resin composition was measured at 20 ° C using a B-type viscometer (trademark, B8H type; manufactured by Tokyo Keiki Co., Ltd., Japan). Moreover, the viscosity of resin (a) was measured at 50 degreeC using the same apparatus. The unit is Pa · s.
(2) Measurement of the number average molecular weight of the resin (a) The average molecular weight of the resin (a) was such that the polydispersity (Mw / Mn) obtained by using the GPC method was greater than 1.1. The number average molecular weight Mn obtained in (1) was adopted. Specifically, the number average molecular weight of the resin (a) was obtained by conversion with polystyrene having a known molecular weight using a gel permeation chromatography method (GPC method). Using a high-speed GPC device (trade name, HLC-8020, manufactured by Tosoh Corporation, Japan) and a polystyrene packed column (trademark: TSKgel GMHXL; manufactured by Tosoh Corporation, Japan), the measurement was performed with tetrahydrofuran (THF). The column temperature was set to 40 ° C. As a sample to be injected into the GPC apparatus, a THF solution having a resin concentration of 1 wt% was prepared, and the injection amount was 10 μl. Further, a resin ultraviolet absorption detector was used as a detector, and light at 254 nm was used as monitor light.

(3) Measurement of the number of polymerizable unsaturated groups The average number of polymerizable unsaturated groups present in the molecule of the resin (a) is determined by removing unreacted low-molecular components using liquid chromatography. Molecular structure analysis was performed using a nuclear magnetic resonance spectrum method (NMR method, manufactured by Bruker Biospin, trademark “Avance 600”). For example, “1.7 functionality” means that the average number of polymerizable unsaturated groups present in the molecule is 1.7.
(4) Application of resin composition (A) to support On transparent cylindrical support made of fiber-reinforced plastic having an outer diameter of 230.00 mm, a width of 300 mm, and a thickness of 1 mm, the surface was silicon-treated. A polyester film was pasted. The resin composition for laser engraving printing original plate was coated on the support while adjusting the thickness to 3 mm with a doctor blade, and kept at 130 ° C. for 60 minutes to be cured to obtain a printing original plate.

(5) Laser engraving Laser engraving was performed using a carbon dioxide laser engraving machine (trademark: ZED-mini-1000, UK, manufactured by ZED, USA, coherent, equipped with an output 250 W carbon dioxide laser). Sculpture images were created with 120 Lines per inch. For the halftone dots, patterns of 1%, 3%, 5%, 10%, 15%, 20%, 30%, 40%, 50%, and 100% were created. A fine line formed a pattern having a width of 250 μm.
Each weight of the printing original plate before laser engraving, the printing plate immediately after laser engraving, and the relief printing plate after wiping was measured, and the residue generation rate at the time of engraving was determined by the following formula.
(Weight of plate immediately after engraving-Weight of plate after wiping) ÷ (Weight of original plate before engraving-Weight of plate after wiping) x 100
The meaning of this formula is the weight caused by the washing machine, accounting for the weight reduced by laser engraving. Therefore, a smaller value means that less engraving residue remains on the plate surface immediately after engraving, and is preferable from the viewpoint of handling the engraving machine. The residue rate of the excellent printing plate is preferably 10% by mass or less, more preferably 5% by mass or less. If the residue remaining rate is 10% by mass or less, subsequent residue cleaning is also simplified.

(6) Engraving quality The relief depth was measured to confirm the quality of the engraved printing original plate. “Relief depth” means a difference in height between a printing portion (relief surface) and a non-printing portion (back surface) of a relief printing plate. If the relief depth is set to be large, the area of the relief surface of the fine halftone dot pattern cannot be secured, and the shape is broken and unclear, so the relief depth is set to 0.5 mm. As confirmation of plate reproducibility, it was observed whether the shape of the dots was conical. “Plate reproducibility” means the accuracy with which a printed image is transferred to a relief printing plate. Further, as a confirmation of the plate reproducibility, it was observed whether the dot shape was conical.

[Production Example 1: Preparation of resin (α1)]
A 1-L separable flask equipped with a thermometer, a stirrer, and a reflux condenser is “X-22-176DF” (number average molecular weight 3206, OH value 35. 0) was added to 474.24 g and tolylene diisocyanate 22.17 g, and the mixture was reacted at 80 ° C. for about 3 hours. Then, 6.42 g of 2-methacryloyloxyisocyanate was added, and further reacted for about 3 hours. A resin (α1) having a number average molecular weight of about 24,000, which is terminated with a methacrylic group (average of about 2.0 unsaturated polymerizable groups in the molecule per molecule) was prepared. This resin contains a siloxane bond in the side chain, is in a water tank shape at 20 ° C., flows when an external force is applied, and does not recover the original shape even when the external force is removed.

[Production Example 2: Preparation of resin (α2)]
A 1-L separable flask equipped with a thermometer, a stirrer, and a reflux condenser is “X-22-176F” (number average molecular weight 12467, OH number 9. 0) was added with 460.79 g and tolylene diisocyanate 3.07 g and reacted at 80 ° C. for about 3 hours, and then added with 2-methacryloyloxyisocyanate 6.00 g and further reacted for about 3 hours. A resin (α1) having a number average molecular weight of about 24,000, which is terminated with a methacrylic group (average of about 2.0 unsaturated polymerizable groups in the molecule per molecule) was prepared. This resin contains a siloxane bond in the side chain, is in a water tank shape at 20 ° C., flows when an external force is applied, and does not recover the original shape even when the external force is removed.

[Production Example 3: Preparation of resin (α3)]
A 1-L separable flask equipped with a thermometer, a stirrer, and a reflux condenser is “X-22-176F” (number average molecular weight 12467, OH number 9. 0) of 369.72 g and 92.43 g of the trademark “PCDL T4672” (number average molecular weight 2018, OH number of 55.6), which is a polycarbonate diol manufactured by Asahi Kasei Corporation, and 9.72 g of tolylene diisocyanate were added at 80 ° C. After reacting for about 3 hours under heating, 6.10 g of 2-methacryloyloxyisocyanate was added, and the reaction was further continued for about 3 hours, and the terminal was a methacryl group (the polymerizable unsaturated group in the molecule was per molecule). A resin (α3) having a number average molecular weight of about 24,000 was prepared (average of about 2.0). This resin contains a siloxane bond in the side chain, is in a water tank shape at 20 ° C., flows when an external force is applied, and does not recover the original shape even when the external force is removed.

[Production Example 4: Preparation of resin (α4)]
A 2L separable flask equipped with a thermometer, a stirrer, and a refluxer is a polycarbonate diol manufactured by Asahi Kasei Corporation. After adding 8 g and reacting at 80 ° C. for about 3 hours, 52.6 g of 2-methacryloyloxyisocyanate was added, and further reacted for about 3 hours, and the terminal was a methacrylic group (polymerizable non-polymerizable in the molecule). A resin (α4) having a number average molecular weight of about 7000 having an average of about 1.7 saturated groups per molecule) was prepared. This resin was in the shape 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.

[Production Example 5: Preparation of resin (α5)]
“GI-2000” (number average molecular weight 2004, OH number 56.0) manufactured by Nippon Soda Co., Ltd., a hydrogenated polybutadiene diol having a carbon chain as a side chain in a 1 L separable flask equipped with a thermometer, a stirrer and a reflux condenser. After adding 502.32 g and g and tolylene diisocyanate 39.74 g and reacting under heating at 80 ° C. for about 3 hours, adding 7.01 g of 2-methacryloyloxyisocyanate and further reacting for about 3 hours. A resin (α5) having a number average molecular weight of about 24,000, which is a methacrylic group at the end (average number of polymerizable unsaturated groups in the molecule of about 2.0 per molecule) was prepared. This resin was in the shape 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.
Table 1 summarizes the compositions of the compounds and resins used in the above production examples.

[Example 1]
T-butylperoxy-2-ethylhexyl carbonate (abbreviated as PBE) as a thermal polymerization initiator (c) (trade name “Perbutyl E” manufactured by NOF Corporation) with respect to 100 parts by mass of the resin (α1) as the resin (a) Was mixed at 2.0 ° C. at 70 ° C. Further, 0.9 parts by mass of 2,6-di-t-butyl-4-methylphenol (abbreviated as DBMP) and bis (1,2,2,6,6-pentamethyl-4-piperidyl) as other additives 1.5 parts by mass of sebacate (abbreviated as BPPS) was added to prepare a liquid resin composition (A1) at 20 ° C.
The viscosity of the resin composition (A1) measured using a B-type viscometer was 3000 Pa · s or less at 20 ° C.
The resin composition (A1) was applied to the support and laser engraving was performed by the method described above. The relief depth was 0.5 mm, and the dot shape was conical.
The state of the residue immediately after engraving was solid with stickiness. Further, the residue generation rate was 5.7%.

[Example 2]
A liquid resin composition (A2) was produced at 20 ° C. in the same manner as in Example 1 except that the resin (α2) was used as the resin (a).
The viscosity of the resin composition (A2) measured using a B-type viscometer was 3000 Pa · s or less at 20 ° C.
The resin composition (A2) was applied to the support and laser engraving was performed by the method described above. The relief depth was 0.5 mm, and the dot shape was conical.
The state of the residue immediately after engraving was powdery. Further, the residue generation rate was 4.3%.

[Example 3]
A liquid resin composition at 20 ° C. in the same manner as in Example 1 except that 50 parts by mass of phenoxyethyl methacrylate (abbreviated as POH) as an organic compound (b) was further added to 100 parts by mass of the resin (a). A3) was prepared.
The viscosity of the resin composition (A3) measured using a B-type viscometer was 3000 Pa · s or less at 20 ° C.
The resin composition (A3) was applied to the support and laser engraving was performed by the method described above. The relief depth was 0.5 mm, and the dot shape was conical.
The state of the residue immediately after engraving was solid with stickiness. Further, the residue generation rate was 6.6%.

[Example 4]
A liquid resin composition at 20 ° C. in the same manner as in Example 2 except that 50 parts by mass of phenoxyethyl methacrylate (abbreviated as POH) as an organic compound (b) was further added to 100 parts by mass of the resin (a). A4) was prepared.
The viscosity of the resin composition (A4) measured using a B-type viscometer was 3000 Pa · s or less at 20 ° C.
The resin composition (A4) was applied to the support and laser engraving was performed by the method described above. The relief depth was 0.5 mm, and the dot shape was conical.
The state of the residue immediately after engraving was powdery. Further, the residue generation rate was 5.2%.

[Example 5]
A liquid resin composition (A5) was produced at 20 ° C. in the same manner as in Example 3 except that the resin (α3) was used as the resin (a).
The viscosity of the resin composition (A5) measured with a B-type viscometer was 3000 Pa · s or less at 20 ° C.
The resin composition (A5) was applied to the support and laser engraving was performed by the method described above. The relief depth was 0.5 mm, and the dot shape was conical.
The state of the residue immediately after engraving was solid with stickiness. Further, the residue generation rate was 5.6%.

[Example 6]
As in Example 5, except that 10 parts by mass of trimethylolpropane trimethacrylate (abbreviated as TMPT) was added to 100 parts by mass of the resin (a) instead of POH as the organic compound (b) of Example 5. Thus, a resin composition (A6) was produced.
The viscosity of the resin composition (A6) measured with a B-type viscometer was 3000 Pa · s or less at 20 ° C.
The resin composition (A6) was applied to the support and laser engraving was performed by the above method. The relief depth was 0.5 mm, and the dot shape was conical.
The state of the residue immediately after engraving was solid with stickiness. Further, the residue generation rate was 7.1%.

[Example 7]
The resin composition (A1) was formed in the same manner as in Example 1 except that the resin composition (A1) of Example 1 was applied while adjusting the coating thickness to 7 mm to obtain a printing original plate. . The original printing plate was completely cured to the inside, and the original shape was secured even when an external force was applied.

[Comparative Example 1]
A liquid resin composition (A7) was produced at 20 ° C. in the same manner as in Example 3 except that the resin (α4) was used as the resin (a).
The viscosity of the resin composition (A7) measured using a B-type viscometer was 3000 Pa · s or less at 20 ° C. at 20 ° C.
The resin composition (A7) was applied to the support and laser engraving was performed by the method described above. The relief depth was 0.5 mm, and the dot shape was conical.
The state of the residue immediately after engraving was a solid with stickiness. Further, the residue generation rate was 11.5%.

[Comparative Example 2]
Comparative Example 1 except that 1.5 parts by weight of methyl styryl-modified silicone oil (trademark “KF-410”) manufactured by Shin-Etsu Chemical Co., Ltd. was added to 100 parts by weight of the resin (a) to the resin composition of Comparative Example 1. In the same manner as in Example 1, a liquid resin composition (A8) was produced at 20 ° C.
The viscosity of the resin composition (A8) measured with a B-type viscometer was 3000 Pa · s or less at 20 ° C. at 20 ° C.
The resin composition (A8) was applied to the support and laser engraving was performed by the method described above. The relief depth was 0.5 mm, and the dot shape was conical.
The state of the residue immediately after engraving was a solid with stickiness. Further, the residue generation rate was 12.4%.

[Comparative Example 3]
A liquid resin composition (A9) was produced at 20 ° C. in the same manner as in Comparative Example 2 except that the resin (α5) was used as the resin (a).
The viscosity of the resin composition (A9) measured using a B-type viscometer was 3000 Pa · s or less at 20 ° C.
The resin composition (A9) was applied to the support and laser engraving was performed by the above method. The relief depth was 0.5 mm, and the dot shape was conical.
The state of the residue immediately after engraving was a solid with stickiness. Further, the residue generation rate was 19.8%.

[Comparative Example 4]
Comparative Example 2 except that 10 parts by mass of silicone rubber “KMP-601” (manufactured by Shin-Etsu Chemical Co., Ltd., trade name) is further added to 100 parts by mass of resin (a) with respect to the resin composition of Comparative Example 2. In the same manner as above, a liquid resin composition (A10) was produced at 20 ° C.
The viscosity of the resin composition (A10) measured using a B-type viscometer was 3000 Pa · s or less at 20 ° C.
The resin composition (A10) was applied to the support and laser engraving was performed by the above method. The relief depth was 0.5 mm, and the dot shape was conical.
The state of the residue immediately after engraving was liquid. Further, the residue generation rate was 12.3%.
The compositions and test results of the above Examples 1 to 6 and Comparative Examples 1 to 4 are summarized in Table 2.
As can be seen from Table 2, in any of the examples, a lower slag generation rate was obtained than in the comparative example. Further, regarding the state of engraving residue, liquid residue was not generated in the examples. That is, a printing original plate is prepared using a resin composition for laser engraving printing original plate containing a resin (a) having a side chain having a siloxane bond and having a number average molecular weight of 1,000 to 300,000 and a thermal polymerization initiator (c). By engraving, a printing original plate having a low residue generation rate, that is, suitable for laser engraving was obtained.
Further, Example 2 had a lower residue generation rate than Example 1, and engraving residue was also in powder form. Moreover, Example 4 had a low residue generation rate compared to Example 3, and engraving residue was also in powder form. This is considered due to the molecular weight of the side chain having a siloxane bond contained in the resin (a).
Further, even when the thickness was 7 mm, the inside was cured, and the ease of thickening by heat curing was confirmed.

According to the present invention, a resin containing a siloxane bond in the side chain and a resin composition containing the resin are excellent in thermal decomposability, and a printing original plate for obtaining a printing plate excellent in the effect of suppressing engraving residue generation during laser engraving Enables the production of In addition, the printing plate in which the generation of engraving residue is suppressed in this way can easily remove the engraving residue in the cleaning process after engraving, and can provide a printing plate with greatly improved printing accuracy. To.
INDUSTRIAL APPLICABILITY The present invention is most suitable as a resin composition for a laser engraving printing original plate capable of improving the removal of residue generated during laser engraving and capable of being easily molded.

Claims (18)

  A resin composition for a laser engraving printing original plate containing a resin (a) having a siloxane bond in a side chain and having a number average molecular weight of 500 to 300,000 and a thermal polymerization initiator (c).   The resin composition for a laser engraving printing original plate according to claim 1, wherein the resin (a) has a polymerizable unsaturated group.   The resin composition for a laser engraving printing original plate according to claim 1 or 2, wherein the resin composition further contains an organic compound (b) having a polymerizable unsaturated group and a number average molecular weight of less than 1000.   The resin composition for a laser engraving printing original plate according to any one of claims 1 to 3, wherein the number average molecular weight of the repeating unit having a siloxane bond contained in the resin (a) is 1000 or more and 30,000 or less.   5. The resin composition for a laser engraving printing original plate according to claim 1, wherein the number average molecular weight of the repeating unit having a siloxane bond contained in the resin (a) is 10,000 or more and 20,000 or less.   6. The laser engraving printing original plate according to claim 1, wherein the resin (a) is a resin having at least one chemical bond selected from the group consisting of a carbonate bond, a urethane bond, and an ester bond. Resin composition.   The resin composition for laser engraving printing original plate according to any one of claims 3 to 6, wherein 20% by mass or more of the total amount of the organic compound (b) is an alicyclic derivative and / or an aromatic derivative.   The resin composition for laser engraving printing original plate according to any one of claims 1 to 7, which is liquid at 20 ° C.   The inorganic fine particles having a number average particle diameter of 0.01 μm or more and 10 μm or less further include 1 to 100 parts by mass with respect to 100 parts by mass of the resin composition for laser engraving printing original plate. The resin composition for laser engraving printing original plate as described in Item 1.   A step of forming the laser engraving printing precursor resin composition according to any one of claims 1 to 9 on a support in a sheet shape or a cylindrical shape, a method of irradiating the formed resin composition with heat rays, hot air A method of producing a laser engraving printing original plate, comprising: a method of spraying, a method of exposing to an atmosphere in which hot air is convected, and a step of curing by at least one method selected from the group consisting of a method of contacting with a heated roll.   A laser engraving printing original plate obtainable by curing the resin composition for laser engraving printing original plate according to claim 1.   The laser engraving printing original plate according to claim 11, further comprising a support on the non-printing surface side of the laser engraving printing original plate.   The laser engraving printing original plate according to claim 12, wherein the support is a hollow cylindrical support.   The laser engraving printing original plate according to claim 12 or 13, further comprising one or more cushion layers between the laser engraving printing original plate and the support.   The laser engraving printing original plate according to claim 14, wherein the cushion layer includes hollow microcapsules.   The laser engraving printing original plate according to any one of claims 13 to 15, further comprising one or more circumferential length adjusting layers between the laser engraving printing original plate and the hollow cylindrical support.   The laser engraving printing original plate according to any one of claims 11 to 16, wherein the outermost surface of the laser engraving printing original plate is surface-adjusted by at least one method selected from cutting, grinding, and polishing.   A printing plate obtained by laser engraving the printing original plate according to any one of claims 11 to 17.