CN106814542B

CN106814542B - Ablation film and application thereof

Info

Publication number: CN106814542B
Application number: CN201510851019.1A
Authority: CN
Inventors: 王晓阳; 高英新; 庞林; 李志勇; 黄永山; 张刚
Original assignee: Lucky Huaguang Graphics Co Ltd
Current assignee: Lucky Huaguang Graphics Co Ltd
Priority date: 2015-11-30
Filing date: 2015-11-30
Publication date: 2020-10-27
Anticipated expiration: 2035-11-30
Also published as: CN106814542A

Abstract

The invention relates to an ablative film and application thereof, the ablative film comprises an imaging layer, a bonding layer and a film base from top to bottom, and the imaging layer contains substances for absorbing, shielding ultraviolet rays and absorbing infrared rays; the base sheet is a frosted base sheet which is subjected to graining treatment, and the grain Ra of the frosted base sheet is 0.15-0.45. The ablative film can greatly improve the ink carrying capacity of the large solid area of the flexographic printing plate under the condition of not using the shallow net technology.

Description

Ablation film and application thereof

Technical Field

The invention belongs to the technical field of printing supplies, and particularly relates to an ablative film and application thereof.

Background

Currently, flexographic plates are widely used for printing of easily deformable or softer printing materials such as cartons, flexible packages, labels and the like.

Generally, a film having a pattern or text is placed on an unexposed flexographic plate containing a photosensitive elastomer, and exposed to ultraviolet light, the film is transparent to the ultraviolet light, and an initiator in the photosensitive elastomer is decomposed into radicals to initiate the reaction of the crosslinkable monomer and cure. The areas which do not transmit ultraviolet rays can not generate cross-linking reaction, and the relief image containing the character and the pattern is obtained by washing and developing by utilizing the difference of the solubility of the areas in developing solution. The developed plate is dried, detackified and post-exposed to ensure complete polymerization of the photosensitive layer. The prepared plate is fixed on a roller of the flexo printing machine and can be ready for printing.

With the development of computer technology and prepress document processing technology, document information with patterns or characters and the like can be converted into digital information, and the digital information is converted into infrared laser, purple laser and the like to be output to a flexible plate by means of computer control, so that plate making without a film is realized. However, there is a problem that dot reduction is caused without using a film plate making method. Since the flexographic plate is exposed to ultraviolet light, oxygen inhibits crosslinking or polymerization of the internal components of the flexographic plate. This causes dot reduction.

The film is closely adhered to a flexible plate for exposure plate making, and can remove the inhibiting effect of oxygen. The surface of a conventional film that is in contact with the flexible plate's elastic photoreceptor is essentially a smooth gelatin plane. The kodak's flat top dot technique does not specifically mention the surface state of the film substrate.

Disclosure of Invention

The invention provides an ablative film and application thereof, the ablative film is used as an exposure film of a flexographic plate, the surface state of a film base of the exposure film is a frosted state, namely, the surface is uneven in a microscopic state, and the ablative film can greatly improve the ink carrying amount of a large real land of the flexographic plate printing plate under the condition of not using a shallow net technology.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the invention provides an ablative film, which comprises an imaging layer, a bonding layer and a film base from top to bottom, wherein the imaging layer contains substances for absorbing, shielding ultraviolet rays and absorbing infrared rays; the base sheet is a frosted base sheet which is subjected to graining treatment, and the grain Ra of the frosted base sheet is 0.15-0.45.

The ablative film of the above, further comprising a protective film coated on the surface of the imaging layer; the thickness of the protective film is generally selected to be 1 to 2 μm.

Pinhole light leakage occurs once the imaging layer is scratched. To avoid this, a protective layer may be added on top of the imaging layer, or of course, this protective layer may be omitted. The thickness of the protective layer is 1-2 mu m. The protective layer also has the characteristic of preventing adhesion with the elastomer. Is favorable for the repeated use of the film. Protective layers, while advantageous, have the disadvantage of increasing the distance between the imaging layer and the elastomer, which can adversely affect the reduction of the dots due to refraction of light. The protective layer should therefore be as thin as possible, if the imaging layer itself is sufficiently strong, without the risk of scratching and the possibility of blocking the elastomer. This protective layer is avoided as much as possible.

The imaging layer also contains a cross-linking agent and a surfactant.

The film base comprises: poly (hexamethylene-2, 6-dicarbonate), polyethylene terephthalate, polybutylene terephthalate, polyvinyl chloride, polypropylene, polycarbonate, cellulose triacetate substrates, and the like, and other polymer sheets can also be used. Any of the abrasive sheet bases produced by a known method such as a sheet prepared by doping the above-mentioned materials with particulate matter can be used as the support of the present invention. Alternatively, a bead-containing coating may be applied between the sheeting and the imaging layer to provide a frosted surface that is exposed after future ablation. In order to increase the exposure latitude of the flexographic plate, the graininess is preferably kept, and generally, the larger the surface roughness Ra value of the sheet is, the stronger the inking capacity of the flexographic plate material made of the ablative film is; meanwhile, the refraction and even reflection of the light by the sand grains can also cause the result of reducing the exposure latitude of the flexographic plate. The Ra value is preferably 0.2 to 0.3. The production of abrasive sheet substrates is a generally known technique. We need only select a substrate using the appropriate grit roughness.

The substrate should have sufficient uv transmission. Doping of particles, coating of beads, or erosion to form grits, etc., do not affect the transmission of ultraviolet light. The frosted film base is prepared by the conventional methods of doping particles in the general film base or polymer sheet or coating the surface of the general film base or polymer sheet with the particles.

The adhesive layer contains a binder, and the binder is an autoxidized polymer, a non-autoxidized polymer, a thermochemical decomposition polymer, a homopolymer or other polymers.

The adhesive layer can firmly fix the imaging layer on the substrate. The layer is firmly attached to the substrate, typically by etching the surface of the substrate, using the rough, uneven surface of the abrasive substrate to anchor the attachment layer to the substrate. The connecting layer usually contains a substance that reacts with the imaging layer to form a chemical bond, thereby achieving the purpose of connecting the two layers.

The imaging layer is described in detail in patent CN102944972A, and its main components are infrared absorbing material, ultraviolet absorbing material, adhesive, crosslinking agent of adhesive, surfactant, etc. The infrared absorption material receives heat of laser infrared rays and drives substances of the whole imaging layer to burn and volatilize, the infrared laser is usually 830nm and 1064nm, and the laser controlled by a computer can burn through selective mesh points to form an image; the ultraviolet absorption material can block the exposure of ultraviolet rays to the photosensitive elastomer; it is generally preferred to use carbon black for both the infrared and ultraviolet absorbing materials so that the film is easily combustible and resists light. The film made of carbon black as an infrared and ultraviolet absorbing material can be used for ablation imaging on the existing laser ablation imaging machine of Esko company, and the equipment investment is not increased.

The binder in the imaging layer may be an autoxidisable polymer such as nitrocellulose, or a non-autoxidisable polymer such as ethylcellulose, polyacrylic acid and salts thereof, a polymer or homopolymer of thermochemically decomposed acrylic acid, styrene, isoprene, butadiene, or a polyvinyl alcohol, polyvinyl chloride, polyacrylonitrile, an amphiphilic polymer or mixtures thereof. Gelatin, polyamide, and the like may be specific examples.

The presence of the crosslinking agent in the imaging layer can make the imaging layer less susceptible to scratching. The component capable of crosslinking the binder is all that is capable of being miscible with the entire coating layer. For example, it may be capable of crosslinking carboxyl groups, hydroxyl groups, amino groups, etc. Examples are described in CN102944972A, such as aziridine for crosslinking amino groups, common thermal crosslinking agents, gelatin hardening agents, chrome alum, aldehydes, alkenyl sulfone hardening agents, and the like.

Surfactants are necessary in order to be able to apply a uniform coating. Suitable surfactants vary depending on the binder and solvent system. If a fluorosurfactant can be used, it is preferably used. The use of fluorosurfactants is particularly advantageous if no protective layer is disposed over the imaging layer. The coating has smooth surface and is not easy to scratch, and in addition, the coating is not easy to adhere to the elastomer.

The ablation film is applied to provide the large and solid partial ink storage quantity of the flexographic plate.

The application of the ablation film in providing the large and solid part ink storage amount of the flexible plate comprises the following specific steps: when the flexible plate is used for plate making, the ablation film is tightly adhered on the flexible plate, and the flexible plate is subjected to traditional plate making exposure to form an image.

Specifically, the ablative film is exposed to ultraviolet light while being in close contact with the flexographic elastic photoreceptor. During exposure, the elastomer temperature is slightly raised, and the elastomer contacts the exposed abrasive sheet base to brand the surface state of the abrasive. After plate making procedures such as plate washing, post exposure, de-sticking and the like are completed, the top end face of the convex part of the elastic body can solidify the frosted imprints of the frosted film base to form an uneven state.

Compared with the prior art, the invention has the advantages that:

the base of the invention is a frosted base, namely the surface has unevenness in a microscopic state, and the ablative film can greatly improve the ink carrying capacity of the large solid area of the flexographic printing plate under the condition of not using a shallow net technology.

Detailed Description

The invention is further described by the following examples, but is not limited thereto.

Example 1

(Standard sample) the support of the laser ablation film uses a photo-film base to manufacture the finished product of the ablation film. After 1064nm laser ablation, a dot image is formed. Then, the imaging surface of the laser ablation film for forming the image is tightly adhered to the elastic body of the flexible plate, and plate making processes such as plate making exposure, plate washing, post exposure, de-sticking and the like are carried out to manufacture the flexible plate capable of printing.

Example 2

The support of the laser ablation film uses a frosted film base with the grain roughness of 0.4-0.6 to manufacture the finished product of the ablation film. After 1064nm laser ablation, a dot image is formed. Then, the imaging surface of the laser ablation film for forming the image is tightly adhered to the elastic body of the flexible plate, and plate making processes such as plate making exposure, plate washing, post exposure, de-sticking and the like are carried out to manufacture the flexible plate capable of printing.

Example 3

The support of the laser ablation film uses a frosted film base with the grain roughness of 0.2-0.3 to manufacture the finished product of the ablation film. After 1064nm laser ablation, a dot image is formed. Then, the imaging surface of the laser ablation film for forming the image is tightly adhered to the elastic body of the flexible plate, and plate making processes such as plate making exposure, plate washing, post exposure, de-sticking and the like are carried out to manufacture the flexible plate capable of printing.

In the above three examples, the conditions were controlled to the same level except that the graininess of the support of the ablative film used was different. The number of the mesh may be varied, but the control of the Ra value of the mesh is the same.

And (4) judging the ink color concentration of the printed product after printing. The ink color of example 2 was significantly darker and the ink color of example 1 was the lightest. The ink application was good in both example 2 and example 3. However, the dots of example 2 are not regular as in examples 1 and 3, and the slope of the dots of example 2 is not good enough. The integrity and inking of the dots of example 3 was good.

Claims

1. An ablative film, it includes imaging layer, tie coat and film base from top to bottom, characterized by that said imaging layer contains the substance which absorbs, blocks the ultraviolet ray and absorbs the infrared ray; the base sheet is a frosted base sheet which is subjected to graining treatment, and the grain Ra of the frosted base sheet is 0.15-0.45; the matte substrate has a grained matte surface on the side of the substrate in contact with the imaging layer.

2. The ablation film of claim 1, wherein: the protective film is coated on the surface of the imaging layer.

3. The ablation film of claim 1, wherein: the imaging layer also contains a cross-linking agent and a surfactant.

4. The ablation film of claim 1, wherein: the abrasive sheet base has a grit Ra of 0.2-0.3.

5. The ablation film of claim 1, wherein: the base sheet is poly (hexamethylene-2, 6-dicarbonate), polyethylene glycol terephthalate, polybutylene terephthalate, polyvinyl chloride, polypropylene, polycarbonate or cellulose triacetate.

6. The ablation film of claim 1, wherein: the adhesive layer contains a binder, and the binder is an autoxidized polymer, a non-autoxidized polymer, a thermochemical decomposition polymer or a homopolymer.

7. The ablation film of claim 1, wherein: the frosted film base is prepared by doping particles in the general film base.

8. The ablation film of claim 1, wherein: the frosted film base is prepared by a method of coating particles on a general polished section base.

9. Use of the ablative film of claim 1 in flexographic plate making.

10. The application of the ablative film to the plate making of the flexographic plate according to claim 9, which is characterized in that the application of the ablative film to the improvement of the substantial partial ink storage of the flexographic plate comprises the following specific steps: when making the plate, the ablated side of the ablative film is tightly adhered to the flexible plate elastic body, and then the plate is made.