JP5903854B2 - Photosensitive resin letterpress printing original plate - Google Patents

Description

  The present invention relates to a photosensitive resin letterpress printing original plate for CTP used for letterpress plates or flexographic plates. More specifically, the present invention relates to a photosensitive resin letterpress printing original plate for CTP having excellent peelability of a protective film (cover film).

  In the photosensitive resin plate, a computer in which a heat-removable mask layer is provided on a photosensitive layer, and a part of the mask layer is removed by irradiation with infrared light based on a signal from a computer, from a conventional method using a negative film. Plate making technology (Computer to Plate: CTP technology) is becoming mainstream. However, in the conventional technology, when the mask layer and the protective film are directly contacted and laminated, there is a problem that the protective film is difficult to peel off.

  On the other hand, the technique of making peeling of a protective film easy by providing the peeling auxiliary layer which consists of polyvinyl alcohol is known (for example, refer Unexamined-Japanese-Patent No. 2004-163925 (patent document 1)). In addition, there is also known a technique for preventing the mask layer from being broken, scratched, or pinholed at the time of peeling the protective film by adding an anionic surfactant to the peeling auxiliary layer made of polyvinyl alcohol (for example, JP 2009-139599 A (see Patent Document 2)).

  However, these conventional techniques are for leaving only the protective film such as polyethylene terephthalate while leaving the peeling auxiliary layer on the mask layer side, and the removal of the mask layer is hindered by the peeling auxiliary layer remaining on the plate side. In addition, there is a problem that the sensitivity (ablation sensitivity) in the ablation process in which the mask layer is removed by infrared light irradiation is lowered.

JP 2004-163925 A JP 2009-139599 A

  The present invention has been made against the background of such prior art problems. That is, the purpose of the present invention is easy to peel off when the protective film is peeled off at the time of plate making, while being easy to handle at the time of proper production and transportation, handling up to the plate making, and excellent in handleability. Furthermore, it is providing the photosensitive resin letterpress printing original plate for CTP used for the letterpress plate or flexographic plate which does not reduce ablation sensitivity.

  The photosensitive resin relief printing original plate of the present invention comprises a support, a photosensitive resin layer, a heat-sensitive mask layer, a peeling force adjustment layer, and a protective film, which are sequentially laminated, and the peeling force adjustment layer. Contains an amino resin.

  In the photosensitive resin relief printing original plate of the present invention, the content of the amino resin is preferably 15% by mass or more with respect to the entire peeling force adjusting layer.

The mask layer in the present invention preferably contains a butyral resin.
Moreover, it is preferable that the mask layer in this invention contains water-soluble or water-dispersible resin further.

  According to the present invention, in the photosensitive resin letterpress printing original plate for CTP, when the protective film is peeled off at the time of plate making, it is easy to peel off, but the protective film may be peeled off at the time of proper production, transportation and handling up to plate making. It is possible to provide a photosensitive resin relief printing original plate for CTP. Moreover, the photosensitive resin relief printing original plate of this invention can maintain high ablation sensitivity, since a mask layer exists in the outermost surface in an ablation process.

It is a figure which shows typically the photosensitive resin relief printing original plate 1 of a preferable example of this invention.

  FIG. 1 is a diagram schematically showing a photosensitive resin relief printing original plate 1 as a preferred example of the present invention. As shown in FIG. 1, the photosensitive resin relief printing original plate 1 of the present invention includes at least a support 2, a photosensitive resin layer 4, a mask layer 5, a peeling force adjustment layer 6, and a protective film 7 that are sequentially laminated. Thus, the peel force adjusting layer 6 contains an amino resin.

  In addition, the photosensitive resin relief printing original plate of this invention shows the photosensitive resin printing original plate used for a letterpress plate or a flexographic plate.

(Support)
The support 2 in the photosensitive resin relief printing original plate 1 of the present invention is flexible, but a material excellent in dimensional stability is preferable. Examples of such support 2 include metal supports such as steel, aluminum, copper, and nickel, and thermoplastic resin supports such as polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, and polycarbonate film. A suitable example is given. Among these, it is particularly preferable to use a polyethylene terephthalate film having excellent dimensional stability and sufficiently high viscoelasticity as the support 2.

  The thickness of the support 2 is not particularly limited, but is preferably in the range of 50 to 350 μm, from the viewpoint of mechanical properties, shape stability, or handleability during plate making, 100 to 250 μm. It is more preferable to be within the range. When the thickness of the support 2 is less than 50 μm, the dimensional stability of the printing plate tends to be impaired, or the support is liable to be damaged during plate making, and when the thickness of the support 2 exceeds 350 μm. This is because the printing plate tends to be difficult to follow along the cylinder when being applied to the cylindrical cylinder.

(Adhesive layer)
As shown in FIG. 1, the photosensitive resin relief printing original plate 1 of the present invention is usually provided with an adhesive layer 3 between them in order to improve the adhesion between the support 2 and the photosensitive resin layer 4. . As the adhesive used for forming the adhesive layer 3, a known appropriate adhesive can be used without any particular limitation. For example, a polyester urethane adhesive or epoxy adhesive obtained by curing a soluble polyester with a polyvalent isocyanate. And the like. Among these, a polyester urethane-based adhesive is preferable because of its excellent adhesiveness to a photosensitive resin, and among polyester urethane-based adhesives, an adhesive composed of polyester and isocyanurate type polyisocyanate is more desirable.

  The adhesive used for forming the adhesive layer 3 may contain an additive as long as the object of the present invention is not impaired. Examples of the additives include plasticizers, dyes, ultraviolet absorbers, antihalation agents, surfactants, and photopolymerizable vinyl monomers.

  Although it does not restrict | limit especially about the thickness of the contact bonding layer 3 in this invention, It is preferable to exist in the range of 1-50 micrometers, and it is more preferable to exist in the range of 5-30 micrometers. This is because when the thickness of the adhesive layer 3 is less than 1 μm, the adhesiveness tends to be insufficient, and when the thickness of the adhesive layer 3 exceeds 50 μm, the production processability tends to decrease. Because it is in.

(Photosensitive resin layer)
The photosensitive resin relief printing original plate 1 of the present invention is preferably adapted for both flexographic and letterpress plates, and is a photosensitive resin layer 4 formed on a support 2 (usually via an adhesive layer 3). As the forming material, materials suitable for the respective materials can be used. When the photosensitive resin relief printing original plate 1 of the present invention is adapted as a flexographic plate, a suitable example is based on a rubber component. When the photosensitive resin relief printing original plate 1 of the present invention is applied as a letterpress plate, a polyamide resin plate, a polyvinyl alcohol resin plate, etc. are preferable, and a water-developable plate is more preferable among these, and a water-developed letterpress. A plate is particularly preferred.

  The photosensitive resin layer 4 used in the photosensitive resin relief printing original plate 1 of the present invention comprises a synthetic polymer compound, a photopolymerizable unsaturated compound and an essential component of a photopolymerization initiator, a plasticizer, a thermal polymerization inhibitor, It is comprised from arbitrary additives, such as dye, a pigment, a ultraviolet absorber, a fragrance | flavor, and antioxidant.

  For example, when applied to a flexographic plate, a synthetic rubber component or a latex component is used as a synthetic polymer compound, and any conventionally known appropriate one can be used without particular limitation. For example, water-dispersed latex and synthetic rubber can be used. A photosensitive resin composition (for example, see JP-A No. 2000-155417), a photosensitive resin composition containing at least two kinds of water-dispersed latex (for example, see JP-A No. 2005-148487), and the like. Can be mentioned. Among these, a photosensitive resin composition containing at least two types of water-dispersed latex is preferable from the viewpoint of achieving both water developability and water-based ink resistance. When a synthetic polymer compound based on such a latex component is used for forming a photosensitive resin layer, the surface hardness before curing has a relatively low hardness in the range of 25 to 45 in terms of A hardness as described later. A photosensitive resin layer can be suitably manufactured. The synthetic polymer compound based on the latex component may of course be a commercially available product. For example, acrylonitrile-butadiene latex Nipol SX1503 (manufactured by Nippon Zeon Co., Ltd.), butadiene latex Nipol LX111NF (manufactured by Nippon Zeon Co., Ltd.) And the like.

  In addition, when applying to the above-described polyamide plate, a conventionally known soluble synthetic polymer compound can be used as the synthetic polymer compound. For example, polyether amide (for example, see JP-A-55-79437), poly Ether ester amide (see, for example, JP-A No. 58-113537), tertiary nitrogen-containing polyamide (see, for example, JP-A No. 50-76055), ammonium salt type tertiary nitrogen atom-containing polyamide (for example, special No. 53-36555), addition polymers of amide compounds having one or more amide bonds and organic diisocyanate compounds (see, for example, JP-A-58-140737), diamines having no amide bond And an organic diisocyanate compound (for example, JP-A-4-9715) No. referring to a publication), and the like. Of these, tertiary nitrogen atom-containing polyamides and ammonium salt type tertiary nitrogen atom-containing polyamides are preferred.

  Also, in the case of adapting to the above-mentioned polyvinyl alcohol plate, a conventionally known appropriate compound can be used as the synthetic polymer compound, for example, 50 mol% to 99 mol% saponified polyvinyl acetate or the like can be used. Of these, 80 to 99 mol% saponified polyvinyl acetate is preferred from the viewpoint of water developability. Of course, commercially available synthetic polymer compounds suitable for such a polyvinyl alcohol plate may be used, and for example, GOHSENOL GH-23 (manufactured by Nippon Synthetic Chemical Co., Ltd.) can be mentioned as a suitable example.

  Examples of the photopolymerizable unsaturated compound include ring-opening addition reaction products of polyglycidyl ether of polyhydric alcohol, methacrylic acid and acrylic acid. Examples of the polyhydric alcohol include dipentaerythritol, pentaerythritol, trimethylolpropane, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, and an ethylene oxide adduct of phthalic acid. Among them, trimethylolpropane is preferable.

  Examples of the photopolymerization initiator include benzophenones, benzoins, acetophenones, benzyls, benzoin alkyl ethers, benzyl alkyl ketals, anthraquinones, thioxanthones, and the like. Specifically, benzophenone, chlorobenzophenone, benzoin, acetophenone, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, benzyl diethyl ketal, benzyl diisopropyl ketal, anthraquinone, 2-ethylanthraquinone , 2-methylanthraquinone, 2-allylanthraquinone, 2-chloroanthraquinone, thioxanthone, 2-chlorothioxanthone and the like.

  As a method for adjusting the surface hardness of the original plate to an appropriate hardness, in the case of adapting to a letterpress plate, the ratio of the hard segment and the soft segment of the synthetic polymer compound of the photosensitive resin layer is adjusted, thereby making the photosensitive resin The surface hardness of the letterpress original plate can be appropriately adjusted, for example, within a range of 65 to 85 in terms of A hardness as described later, or within a range of 25 to 45 in terms of A hardness. For example, conventionally known methods can be used to adjust the surface hardness of the printing original plate. For example, a synthetic polymer compound with a large number of hard segments may be used to increase the hardness, and a soft method may be used to decrease the hardness. A synthetic polymer compound having many segments may be used.

  Examples of the method for adjusting the surface hardness of the flexographic plate precursor include a method for increasing or decreasing the content of the latex component used as the synthetic polymer compound in the photosensitive resin.

  In the photosensitive resin relief printing original plate 1 of the present invention, the thickness of the photosensitive resin layer 4 is not particularly limited, but is preferably in the range of 350 to 700 μm. When the thickness of the photosensitive resin layer 4 is less than 350 μm, ink may adhere to the adhesive layer on the support and stains (background stains) may occur in the non-image area of the printed matter. On the other hand, if the thickness of the photosensitive resin layer 4 exceeds 700 μm, the reproducibility of fine points during plate making may be reduced. In particular, since the total thickness of the printing plate used for rotary seal label printing is as large as 800 μm or 950 μm, the thickness of the photosensitive resin layer 4 is preferably in the range of 450 to 700 μm, and in the range of 490 to 650 μm. More preferably.

(Mask layer)
In the photosensitive resin relief printing original plate 1 of the present invention, the mask layer 5 having heat sensitivity formed on the photosensitive resin layer 4 has, for example, a function of absorbing infrared laser and converting it into heat and a function of blocking ultraviolet rays. Preferably, it is comprised from the carbon black which is a material which has this, and its dispersion | distribution binder. Moreover, the mask layer 5 can contain a pigment dispersant, a filler, a surfactant, a coating aid, and the like as optional components other than these as long as the effects of the present invention are not impaired. Such mask layer 5 is formed by appropriately combining known materials.

  Carbon black used for the mask layer 5 is classified into furnace black, channel black, thermal black, acetylene black, lamp black, etc., depending on its manufacturing method. Furnace black is of various types in terms of particle size and other aspects. Since it is commercially available and is commercially inexpensive, it is preferably used. In addition, those having excellent dispersion stability such as a carbon black aqueous dispersion and a carbon black alcohol dispersion are preferably used from the viewpoint of ease of production of the dispersion.

  The dispersion binder used for the mask layer 5 preferably contains a water-soluble or water-dispersible resin, an alcohol-soluble resin, or the like.

  In particular, the dispersion binder of the mask layer 5 in the present invention preferably contains a water-soluble or water-dispersible resin. By containing the water-soluble or water-dispersible resin, the mask layer 5 can be easily dispersed in the aqueous developer during development. As such a water-soluble or water-dispersible resin, a polar group-containing resin is preferable from the viewpoint of dispersibility in an aqueous developer, and specifically, polyvinyl alcohol, polyvinyl acetate, partially saponified polyvinyl alcohol, hydroxy Suitable examples include alkyl cellulose, alkyl cellulose, polyamide resin, and the like.

  Among the above, polyamide resins are preferable from the viewpoint of dispersibility of carbon black. For example, polyether amide (see, for example, JP-A-55-79437), polyether ester amide (for example, JP-A-58-117537). No. 3), tertiary nitrogen-containing polyamide (see, for example, JP-A-50-7605), ammonium salt type tertiary nitrogen-containing polyamide (see, for example, JP-A-53-36555) And sulfonic acid group-containing polyamide (see, for example, Japanese Patent Publication No. 49-27522). Of these, tertiary nitrogen atom-containing polyamides and ammonium salt type tertiary nitrogen atom-containing polyamides are preferred. Of course, a commercially available resin may be used as the water-soluble or water-dispersible resin. These polyamide resins give not only dispersibility of the developing solution of the mask layer 5 but also toughness, and can be made difficult to be damaged.

  In addition, when the mask layer 5 contains the above-described water-soluble or water-dispersible resin, the peeling force with the peeling force adjusting layer may be too low in a generally known release coating. . However, the original plate of the present invention can adjust the surface free energy of the peeling force adjusting layer to an appropriate value because the peeling force adjusting layer contains an amino resin.

  When the mask layer 5 contains the above-described water-soluble or water-dispersible resin, the content thereof is preferably in the range of 5 to 75% by mass with respect to the entire mask layer, and 10 to 65% by mass. It is preferable to be within the range. This is because when the content of the water-soluble or water-dispersible resin in the mask layer is less than 5% by mass with respect to the entire mask layer, the developability tends to be insufficient, and it exceeds 75% by mass. In this case, the amount of carbon black is insufficient and the light shielding property tends to be lacking.

  Examples of the alcohol-soluble resin include alcohol-soluble polyamide resins, polyurethane resins, and polyvinyl acetal resins. Among these, the alcohol-soluble resin is preferably a polyvinyl acetal resin from the viewpoint of the dispersibility of carbon black, and is a polyvinyl butyral resin because it can improve the dispersibility of carbon black and contribute to high light shielding properties. It is more preferable. Of course, commercially available alcohol-soluble resins may be used. The polyvinyl butyral resin can also be synthesized by a manufacturing method described in, for example, Japanese Patent Application Laid-Open No. 2008-13676.

  When the mask layer 5 contains the alcohol-soluble resin described above, the content thereof is preferably in the range of 5 to 75% by mass, and in the range of 10 to 65% by mass with respect to the entire mask layer. It is preferable. This is because when the content of the alcohol-soluble resin in the mask layer is less than 5% by mass with respect to the entire mask layer, the film-forming property tends to be lacking. This is because the black amount is insufficient and the light shielding property tends to be lacking.

The mask layer 5 preferably has an optical density of 2.0 or more with respect to ultraviolet rays, more preferably an optical density of 2.0 to 3.0, and an optical density of 2.2 to 2.5. Particularly preferred. This is because when the optical density of the mask layer with respect to ultraviolet rays is less than 2.0, the function of blocking ultraviolet rays is insufficient and the non-image area may be exposed. The optical density is generally represented by D and is defined by the following equation: D = log ₁₀ (100 / T) = log ₁₀ (I ₀ / I)
(Where T is the transmittance (unit is%), I ₀ is the incident light intensity when measuring the transmittance, and I is the transmitted light intensity), for example, a black and white transmission densitometer DM-520 (Dainippon Screen Manufacturing ( It refers to the value measured by the company).

  The thickness of the mask layer 5 is not particularly limited, but the lower limit thereof is preferably 0.1 μm, more preferably 0.5 μm, and particularly preferably 1.0 μm. When the thickness of the mask layer 5 is less than 0.1 μm, the mask layer may be inferior in the function of blocking ultraviolet rays. Further, the upper limit of the thickness of the mask layer is preferably 3.0 μm, more preferably 2.5 μm, and further preferably 2.0 μm. When the thickness of the mask layer exceeds 3.0 μm, high energy may be required for evaporation of the mask layer.

  In the photosensitive resin relief printing original plate 1 of the present invention, a dividing layer may be provided between the photosensitive resin layer and the mask layer. When the divided layer is provided, suitable forming materials include polyvinyl alcohol and partially saponified polyvinyl acetate. By providing such a divided layer, there is an effect that photopolymerization inhibition by oxygen can be prevented. In order to exhibit the effect by such a dividing layer suitably, it is preferable that the thickness of a dividing layer exists in the range of 0.1-10 micrometers, and it is more preferable that it exists in the range of 0.3-5 micrometers.

(Peeling force adjustment layer)
In the photosensitive resin relief printing original plate 1 of the present invention, the release force adjusting layer 6 formed on the mask layer 5 is provided for the purpose of controlling the peelability of the protective film 7 and contains an amino resin. is there. As the amino resin, a methylated melamine resin, a butylated melamine resin, a methylated urea resin, a butylated urea resin, a methylated benzoguanamine resin, a butylated benzoguanamine resin, and a mixture thereof are more preferable. To butylated urea resin, butylated melamine resin, and mixtures thereof are more preferable. Of course, commercially available amino resins may be used. For example, Super Becamine ODL131-60 (manufactured by DIC Corporation) as a butylated urea melamine resin, and Becamine P-196-M (butylated urea resin). As a butylated melamine resin, Becamine J-820-60 (manufactured by DIC Corporation) is exemplified.

  By containing such an amino resin, unlike the case of containing other resins, a peeling force adjusting layer having excellent surface smoothness can be formed, and the mask layer 5 is applied to the peeling force adjusting layer 6. Not only can there be less scratches during the process, but the composition of the mask layer 5 and the selection range of the coating solvent can be widened, making it easy to adjust the peeling force.

  The lower limit of the content of the amino resin in the peeling force adjusting layer 6 is preferably 15% by mass and more preferably 20% by mass with respect to the entire peeling force adjusting layer 6. When the content of the amino resin contained in the peeling force adjusting layer is less than 15% by mass, the peeling force is too low, and there is a possibility of peeling during handling. On the other hand, the upper limit of the content of the amino resin in the peeling force adjusting layer 6 is 100% by mass. In addition, since the effect by containing an amino resin may be saturated, the upper limit of the content of the amino resin is preferably 100% by mass, more preferably 98% by mass, and still more preferably 95% by mass. %.

  In general, the peeling force greatly depends on the hardness of the surface of the photosensitive resin layer 4 before curing. According to the present invention, it is possible to easily obtain an appropriate peeling force by adjusting the content of the amino resin contained in the peeling force adjusting layer 6.

  For example, the surface hardness of the photosensitive resin layer 4 before curing is A hardness (for example, the durometer A type (manufactured by Kobunshi Keiki Co., Ltd.) is used to peel the cover film of the printing plate before curing and measure the surface). In the case of a 65-85 photosensitive resin relief printing original plate, the lower limit of the amino resin content in the peel force adjusting layer 6 is preferably 50% by mass, more preferably 60% by mass, and even more preferably 70% by mass. It is. In this case, when the content of the amino resin in the peeling force adjusting layer 6 is less than 50% by mass, the peeling force is too low and the peeling may occur during handling. In this case, the upper limit of the content of the amino resin in the peeling force adjusting layer 6 is preferably 100% by mass, more preferably 98% by mass, and still more preferably 95% by mass. Even if the content of the amino resin in the peeling force adjusting layer 6 exceeds 100% by mass, the effect may be saturated.

  For example, the surface hardness of the photosensitive resin layer 4 before curing is A hardness (for example, the cover film of the printing plate before curing is peeled off using a durometer A type (manufactured by Kobunshi Keiki Co., Ltd.) and the surface is measured) In the case of the photosensitive resin relief printing original plate of 25 to 45, the lower limit of the content of the amino resin is preferably 15% by mass, more preferably 20% by mass, and further preferably 25% by mass. In this case, when the content of the amino resin in the peeling force adjusting layer 6 is less than 15% by mass, the peeling force is too low and the peeling may occur during handling. In this case, the upper limit of the content of the amino resin in the peeling force adjusting layer 6 is preferably 75% by mass, and more preferably 70% by mass. If the content of the amino resin in the peeling force adjusting layer 6 exceeds 75% by mass, the peeling force may become too high, causing a problem.

  In the photosensitive resin relief printing original plate 1 of the present invention, the protective film 7 is peeled off during plate making, and then the mask layer 5 is removed in accordance with the pattern of the image with an infrared laser. When the protective film 7 is peeled, it is necessary to peel the protective film 7 without applying an excessive force between the peel force adjusting layer 6 and the mask layer 5. On the other hand, an adhesive force that prevents the protective film 7 from being peeled off is necessary from the time of manufacture to the peeling at the time of peeling.

  The lower limit of the peeling force between the peeling force adjusting layer 6 and the mask layer 5 is preferably 15 gf / cm, more preferably 20 gf / cm. If the peeling force is less than 15 gf / cm, the peeling force is too low, and there is a risk of peeling during handling. Further, the upper limit of the peeling force is preferably 50 gf / cm, more preferably 48 gf / cm, and particularly preferably 45 gf / cm. When the peeling force exceeds 50 gf / cm, it may be difficult to peel off during plate making, a peeling force adjusting layer may remain on the plate, or the mask layer may peel off. Specifically, when the content of the amino resin in the peeling force adjusting layer 6 is increased, the peeling force can be increased. As described above, the mask layer 5 in the present invention preferably contains a water-soluble or water-dispersible resin, but the release force adjusting layer 6 contains an amino resin so that the peeling force adjusting layer 6 includes the amino resin. It is considered that the surface free energy can be brought close to the surface free energy of the mask layer 5, whereby the peeling force can be adjusted by the content of the amino resin in the peeling force adjusting layer 6.

  A resin other than an amino resin may be added to the peeling force adjusting layer 6 in the present invention. Examples of such resins other than amino resins include acrylic resins, alkyd resins, polyester resins, urethane resins, polyamide resins, and epoxy resins. Among these resins, acrylic resins are preferred because of their excellent compatibility with amino resins. Resins are preferred, and alkyd resins are preferred because they are excellent in the effect of adjusting the peel force.

  As the acrylic resin, a long-chain alkyl (preferably having 12 to 22 carbon atoms) acrylate copolymerized alkyl resin is preferable from the viewpoint of easily exerting the effect of adjusting the peeling force adjustment. As such a long-chain alkyl acrylate copolymer alkyl resin, a commercially available product may of course be used, and for example, pyroyl (manufactured by Yushi Kogyo Co., Ltd.) and the like are preferable examples.

  When the peeling force adjusting layer 6 contains an acrylic resin in addition to the amino resin, the content of the acrylic resin is preferably in the range of 1 to 80% by mass with respect to the entire peeling force adjusting layer 6. More preferably, it is within the range of 70% by mass. When the content of the acrylic resin is less than 1% by mass with respect to the entire peeling force adjusting layer 6, there is a possibility that the peeling force becomes too high and it is difficult to peel off the protective film during plate making. When it exceeds%, the peeling force becomes too low and the protective film may be easily peeled off during plate making.

  As the alkyd resin, the oil length (ratio of oil to the resin component) is preferably in the range of 0 to 65, more preferably in the range of 35 to 55 because the effect of adjusting the peeling force is easily exhibited. Alkyd resins are preferred. From the viewpoint of storage stability of the coating solution, the acid value is preferably in the range of 1 to 30, more preferably in the range of 5 to 25, and the hydroxyl value is preferably in the range of 50 to 300, more preferably. It is preferable to use an alkyd resin in the range of 100 to 250. As such alkyd resin, those produced using animal and vegetable oils or animal and vegetable oil fatty acids, various saturated fatty acids and the like can be preferably used, and commercially available alkyd resins such as Teslac (manufactured by Hitachi Chemical Polymer Co., Ltd.) can be used. Of course, a resin can also be suitably used.

  When the peeling force adjusting layer 6 contains an alkyd resin in addition to the amino resin, the content of the alkyd resin is preferably in the range of 1 to 80% by mass with respect to the entire peeling force adjusting layer 6. More preferably, it is within the range of 70% by mass. When the content of the alkyd resin is less than 1% by mass with respect to the entire peeling force adjusting layer 6, there is a possibility that the peeling force becomes too high and the protective film is difficult to peel off during plate making. When it exceeds mass%, there exists a possibility that a peeling force may become low too much and a protective film may peel easily at the time of platemaking.

  The thickness of the peeling force adjusting layer 6 is not particularly limited, but the lower limit thereof is preferably 0.01 μm, more preferably 0.03 μm, and further preferably 0.05 μm. When the thickness of the peel force adjusting layer is less than 0.01 μm, the peel force adjusting layer 6 may not sufficiently exhibit the effect of peeling force. Moreover, the upper limit of the thickness of the peeling force adjusting layer 6 is preferably 10 μm, more preferably 7 μm, and further preferably 5 μm. If the thickness of the peeling force adjusting layer 6 exceeds 10 μm, uneven coating may occur and the economy may be inferior.

  The peeling force adjusting layer 6 in the present invention preferably contains a curing accelerator for curing the amino resin. As the curing accelerator, an acidic catalyst is preferable, and paratoluenesulfonic acid, hydrochloric acid, and the like are more preferable.

  Moreover, leveling agents, such as surfactant, a thickener, a coloring agent, etc. may be added to the peeling force adjustment layer 6 in this invention. In addition, since there exists a possibility that a silicone type compound may transfer to a mask layer and may cause the repellency of an ink at the time of printing, it is preferable not to use for a peeling force adjustment layer.

(Protective film)
The protective film 7 in the present invention is preferably a material having flexibility and excellent dimensional stability, and suitable examples thereof include, for example, a polyethylene terephthalate film, a polyethylene naphthalate film, a polybutylene terephthalate film or A film made of a thermoplastic resin such as a polycarbonate film can be mentioned. Among these, a polyethylene terephthalate film having excellent dimensional stability and sufficiently high viscoelasticity is particularly preferable.

  The thickness of the protective film 7 is not particularly limited, but is preferably in the range of 50 to 350 μm from the viewpoint of mechanical properties, shape stability, or handling properties during plate making, and is preferably 100 to 250 μm. More preferably within the range.

  The total thickness of the photosensitive resin relief printing original plate 1 of the present invention is not particularly limited, but is preferably in the range of 100 to 1000 μm, and more preferably in the range of 300 to 950 μm. If the total thickness of the photosensitive resin relief printing original plate 1 is less than 100 μm, it may be difficult to control the thickness during molding, and if it exceeds 1000 μm, it is disadvantageous in terms of cost. This is because there is a fear.

(Method for producing photosensitive resin relief printing original plate)
Although it does not specifically limit as a manufacturing method of the photosensitive resin letterpress printing original plate 1 of this invention, Generally, it manufactures as follows.

  The method for forming the peeling force adjusting layer 6 is not particularly limited, but for ease of thin film formation, the solvent is applied after coating the support member (for example, PET film) with the peeling force adjusting layer component dissolved in the solvent. A method of removing is preferably performed. The solvent is not particularly limited, but water, alcohol, or a mixture of water and alcohol is mainly used.

  The method for forming the mask layer 5 is not particularly limited, but components other than carbon black are dissolved in an appropriate solvent, and the solvent is removed after coating on the peeling force adjusting layer 6 with carbon black dispersed therein. The method is preferably performed.

  Thereby, the laminated body which consists of a supporting member, the peeling force adjustment layer 6, and the mask layer 5 is obtained. The support member functions as a protective film 7 on the surface of the photosensitive resin relief printing original plate 1 after completion.

  Furthermore, the photosensitive resin layer 4 is formed on the support 2 different from this by the adhesive layer 3 by coating, and the other laminated body is created. The two laminated bodies thus obtained are laminated so that the photosensitive resin layer 4 is adjacent to the mask layer 5 under pressure and / or heating.

  As a method for producing a printing plate from the photosensitive resin relief printing original plate 1 of the present invention, the protective film 7 is first removed. Thereafter, the mask layer 5 is irradiated imagewise with an IR laser to form a mask on the photosensitive resin layer 4. Examples of suitable IR lasers can include ND / YAG lasers (eg, wavelength 1064 nm) or diode lasers (eg, wavelength 830 nm). Laser systems suitable for computer plate making technology are commercially available, and for example, CDI Spark (Esco Graphics) can be used. This laser system includes a rotating cylindrical drum that holds a photosensitive resin relief printing original, an IR laser irradiation device, and a layout computer, and image information is directly transferred from the layout computer to the laser device.

  After writing the image information on the mask layer 5, the entire surface of the photosensitive resin relief printing original plate 1 is irradiated with ultraviolet rays through the mask layer 5. This can be done with the plate attached to the laser cylinder, but removing the plate from the laser device and irradiating with a conventional flat irradiation unit is advantageous in that it can cope with non-standard plate sizes. It is general. As the ultraviolet rays, ultraviolet rays having a wavelength of 150 to 500 nm, particularly 300 to 400 nm can be suitably used. As the light source, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, a xenon lamp, a zirconium lamp, a carbon arc lamp, an ultraviolet fluorescent lamp, or the like can be used.

  After the exposure, the non-exposed portion is dissolved and removed using an appropriate solvent, preferably an aqueous developer, more preferably water, so that the development is performed quickly and a printing plate (relief plate) is obtained. As the developing method, it is preferable to use a spray developing device, a brush developing device, or the like.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

(Preparation of peel strength adjusting layer)
According to the composition (mass ratio) described in Table 1, the resin and the curing agent were dissolved in a solvent to prepare a peeling force adjusting layer composition liquid. Peeling force adjusting layer composition on PET film support member (E5000, Toyobo Co., Ltd., thickness: 100 μm) (functioning as a protective film when used as a photosensitive resin relief printing original) on both sides The liquid was applied using a bar coater appropriately selected so that the layer thickness was 1.0 μm, and dried and cured under the conditions of 160 ° C. × 3 minutes to prepare a peeling force adjusting layer.

(Manufacture of mask layer)
Carbon black dispersion (AMBK-8, manufactured by Orient Chemical Co., Ltd.) and copolymerized polyamide (PA223, manufactured by Toyobo Co., Ltd.) at a solid content mass ratio of carbon black dispersion: copolymerized polyamide = 63: 37 Then, it was dissolved in a solvent to obtain a mask layer composition liquid. The mask layer composition liquid is applied to the peeling force adjusting layer side of the PET film support member provided with the above-described peeling force adjusting layer using a bar coater appropriately selected so that the layer thickness becomes 1.5 μm, 120 A mask layer was prepared by drying at 5 ° C. for 5 minutes, and a laminated film X was obtained.

(Preparation of photosensitive resin relief printing original plate [letter press original plate])
50 parts by mass of ε-caprolactam, 40 parts by mass of N, N′-bisaminopropylpiperazine adipate and 10 parts by mass of 1,3-bis (aminomethyl) cyclohexane adipate are polymerized to have a melting point of 137 ° C. and a specific viscosity of 1.96. A tertiary nitrogen-containing polyamide was obtained. 55 parts by mass of the obtained polyamide was dissolved in 200 parts by mass of methanol and 24 parts by mass of water. In this solution, 3 parts by mass of methacrylic acid, trimethylolpropane triglycidyl ether, 35 mol% of acrylic acid and 65 mol% of methacrylic acid were added. 36 parts by mass of the reaction product, 5 parts by mass of N-ethyl-p-toluenesulfonamide, 0.1 part by mass of hydroquinone monomethyl ether, and 1 part by mass of benzyl dimethyl ketal were added to obtain a photosensitive resin composition solution. This photosensitive resin composition solution was sent to a concentrator and concentrated at 110 ° C. to obtain a photosensitive resin composition A. Next, a 250 μm PET film (support) was coated with 20 μm of adhesive, the photosensitive resin composition A was sandwiched between the adhesive coated surface side and the laminated film X, and heated and pressed at 110 ° C. A photosensitive resin relief printing original plate having a total thickness of 950 μm was prepared. The surface hardness was 67 as D hardness.

(Preparation of photosensitive resin letterpress printing original plate [flexographic printing original plate])
Acrylonitrile-butadiene latex (Nipol SX1503, manufactured by Nippon Zeon Co., Ltd., nonvolatile content: 42%) 10 parts by mass, butadiene latex (Nipol LX111NF, manufactured by Nippon Zeon Co., Ltd., nonvolatile content: 55%) 58 parts by mass, oligobutadiene 28 parts by mass of acrylate (ABU-2S, manufactured by Kyoeisha Chemical Co., Ltd.), 4 parts by mass of lauryl methacrylate (Light Ester L, manufactured by Kyoeisha Chemical Co., Ltd.), 4 parts by mass of dimethylol tricyclodecane diacrylate, photopolymerization initiator 1 part by weight, 0.1 part by weight of hydroquinone monomethyl ether as a polymerization inhibitor, and 0.1 part by weight of a nonionic surfactant as another additive are mixed together with 15 parts by weight of toluene in a container, and then a pressure kneader is used. Use and knead at 105 ° C, then remove toluene and water under reduced pressure By, to obtain a photosensitive resin composition B. Next, the photosensitive resin composition B is sandwiched between the adhesive film-coated side of the support film obtained by coating the adhesive film on the 250 μm PET film to 20 μm, and heated and pressed at 110 ° C. Thus, a photosensitive resin relief printing original plate having a total thickness of 950 μm was prepared. The surface hardness of the photosensitive resin layer measured as described below was 35 in A hardness.

(Performance evaluation)
(1) Peeling force The photosensitive resin relief printing original plate produced as a test piece is cut into 150 mm × 50 mm, the end of one laminated film X is peeled off with a fingertip, set on a tensile tester, and at a speed of 1000 mm / min. The film was pulled at 90 °, and the peel force W (g / 50 mm) was measured. The measurement was performed in a room at a temperature of 25 ° C. and 45 RH%.

(2) Surface hardness of photosensitive resin layer A photosensitive resin letterpress printing original plate was produced as a printing original plate for surface hardness measurement in the same manner as in each Example and Comparative Example, and the protective film was peeled off. The surface hardness of the photosensitive resin layer was measured using a meter (manufactured by Keiki Co., Ltd.).

(3) Easy handling of plate and easy peeling of protective film The prepared photosensitive resin relief printing original plate was cut into A4 size with a cutting machine, placed in a paper bag laminated with a light-shielding film, and stored on a table. The next day, the photosensitive resin relief printing original plate was taken out from the paper bag, the protective film was peeled off, and the plate was set in an ablation apparatus for plate making. In a series of operations, peeling of the protective film was visually observed.

○: Slight peeling of the protective film was observed at the edge at the time of cutting, but no further peeling was observed, or no peeling was observed at the time of cutting,
Δ: Some increase in peeling was observed during handling, such as taking in and out of paper bags.
X: Significant enlargement of peeling was observed during handling such as taking in and out of a paper bag.

Whether the protective film was easily peeled off was judged according to the following criteria.
○: Easily peeled off
Δ: It was difficult to grasp the trigger of peeling, or the peeling resistance was large, but peeling between the mask layer and the peeling force adjusting layer was possible.
X: Peeling is difficult, and when the protective film was peeled off, the mask layer and the peeling force adjusting layer were not peeled off, and the mask layer was peeled off.

  The results are shown in Table 1.

  According to the photosensitive resin relief printing original plate of the present invention, the protective film can be easily peeled off during plate making, but the protective film is not peeled off during handling such as during manufacturing, and further, the ablation sensitivity is not lowered. . The present invention is a technology that meets the demand for high-quality printing in recent years and has a great potential to contribute to the industrial world.

  DESCRIPTION OF SYMBOLS 1 Photosensitive resin relief printing original plate, 2 support body, 3 contact bonding layer, 4 photosensitive resin layer, 5 mask layer, 6 peeling force adjustment layer, 7 protective film.

Claims (4)

A photosensitive resin letterpress printing original plate in which a support, a photosensitive resin layer, a heat-sensitive mask layer, a peeling force adjustment layer, and a protective film are sequentially laminated,
The mask layer is composed of carbon black and its dispersion binder,
The photosensitive resin letterpress printing original plate, wherein the peeling force adjusting layer contains any one selected from butylated urea melamine resin, butylated urea resin, and butylated melamine resin .   2. The photosensitive resin relief printing original plate according to claim 1, wherein the content of the amino resin is 15% by mass or more with respect to the entire peeling force adjusting layer. The photosensitive resin relief printing original plate of Claim 1 or 2 with which the dispersion | distribution binder which comprises the said mask layer contains polyvinyl butyral resin. The photosensitive resin letterpress printing original plate in any one of Claims 1-3 in which the dispersion | distribution binder which comprises the said mask layer contains water solubility or a water dispersible resin further.

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