JPS6083893A - Laser contrast material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser-enhanced contrast material and a method for forming positive and negative images by exposure to radiation produced by a laser through a transparent photoconductive film. This relates to the old overlay material used. Such negative and positive film watermarks can be used as film masters, as long as they are not completely transparent to ultraviolet and OJ visual rays.

Film masters are commonly used in the printing industry when carrying out operations in which printing plates coated with photosensitive compositions are exposed to actinic radiation. Depending on the nature of the composition, this radiation selectively solubilizes or insolubilizes the coating in the irradiated areas. The resulting image is then developed, whereby soluble substances remaining in the coating as a result of exposure are removed by the action of a conventional solvent. It is important that the contrast areas of the film master used to expose the printing plate have a sufficiently high yC density to act as an effective light shielding material. It is equally important that those areas of the film master not covered by the coating have a very low optical density to the radiation used during exposure. The non-contrast areas of the film master are advantageously completely transparent to the exposure radiation, and thus the exposure times used can be as short as practicable.

Coated film coatings suitable for imaging printing plates and/or for forming film masters by means of laser beams have already been proposed.

British Patent No. 1.3.85.533 discloses that 17-z-rays are passed through a transparent film support carrying a layer consisting of a radiation-absorbing pigment such as carbon black dispersed in a self-combustible binder. Describes a method of recording data in a visible form by assigning it to -C. The heat generated by the absorption of radar energy also causes the layer to separate from the support in the irradiated area.

In the above method, exposure is carried out on the coated surface in intimate contact with the receptor sheet to which the laser-removable coating is transferred. When the radar beam is adjusted to form a positive image on the coated film, a negative image is formed on the receptor sheet, and vice versa. Coated film materials, generally operated in the same manner, U.S. Pat. No. 3,964,389 and describes a coating of laser energy absorbing particles dispersed in a mixture of a self-oxidizing binder and one or more crosslinking additives. It consists of a supporting transparent support.

The film material used is exposed to radar energy through the transparent support while the coating is in contact with the lithographic surface. In areas exposed to radar radiation,
The coating is transferred to the lithographic surface. The transferred coating is then surface cured by heat, which cures the additives present by the crosslinking agent. In this way,
A durable printing plate is formed, which serves as a positive image of the image.
:L It is stated that it is a negative drawing.

When any of the known film materials of E is used as described above, the transfer of the coating from the transparent substrate gives a negative or positive watermark of the transferred image.

Such watermarks are useful for imaging photographic materials, especially lithographic and printed letter plates using light-sensitive coatings. Use as an exposure master for producing printing plates K 11 When a picture or negative film master is produced in this way:
It is important that the laser beam removes the layers as cleanly and completely as possible. The efficiency of layer removal depends not only on the composition of the coating, but also on the intensity and duration of the laser exposure. A particularly well-known radar source with widespread industrial application has a wavelength of 1.06 x 10-”
It is a solid yttrium aluminum garnet or YAG laze that provides infrared radiation of 1,06 microns).

The practical operating power range for a YAG laser is 5 to 5 degrees. Currently, commercially available equipment for graph ink art typically operates over a power range of 5 to 15 wands. At the calculated power values, a scanning speed is used that gives an area of 0.2 to 0.5 m2 subjected to a time exposure of 2 to 5 minutes Ikl. The laser exposes the heat-sensitive coated film paulownia wood by scanning it through a transparent plastic support in a circumferentially varying helical mask (scanning spot trajectory) pattern. The laser energy conducted during short, intense exposures is transferred to transparent supports and IR
It is effectively absorbed at the interface between the layers containing absorbent materials. The sudden generation of heat caused by this absorption thermally decomposes the layer at this interface, and the gas generated in this exposed area pushes the coating up off the support and into intimate contact with the coated surface of the film material during exposure. allowing this to be transferred to a suitable receptor surface held in contact with the receptor surface. The scanning radar beam is like a bell.

It can be adjusted to form positive or negative images.

The production of film masters in this way has the disadvantage that incomplete transfer of the layers occurs, resulting in incompletely transparent open areas of the film master.

U.S. Patent No. 4,245. In order to overcome this difficulty, No. O'03 describes the use of graphite instead of carbon graphite as a radiation absorbing pigment.

The layer containing graphite and ethyl cellulose is said to be more easily removed with a single laser beam, allowing for much lower laser powers or faster exposure times (writing speeds) to be used. Such graphite-containing coatings provide satisfactory transfer at high scan speeds and industrially useful laser power ratings, as demonstrated by the small coatings in the 1,'l range left on the support. As shown by measuring its optical density, graphite provides a coating with poor adhesive strength, aggregation strength, and abrasion resistance. These drawbacks make such coatings difficult to handle due to their tendency to scrape and wear away.
Make it. More importantly, the adhesion and abrasion resistance defects exhibited by overcast coatings render the produced positive and negative film masters unsuitable for use as exposure masters with printing plates in the desired manner. However, this occurs due to separation of the coating from the film mask as a result of adhesion to the printing plate light surface or abrasion thereby during the contact exposure operation. Inferior quality papers can be mentioned below.

Prior art pigmented organic coatings have a very thin thickness, preferably from 0.5 to 6.0 microns, in order to be completely removable during one laser exposure. It is also generally true that the thinner the coating layer, the less laser energy is required to transfer it from the film support to the receptor surface. Coatings thinner than about 0.5μ are not useful in practice because their optical density is not high enough to serve as an exposure master in subsequent platemaking operations. The photosensitive coatings of the most widely used industrially used printing plates undergo photochemical reactions when exposed to radiation at wavelengths as low as 5 LI Onm, resulting in optical densities greater than 2.0 in the ultraviolet and evening spectral regions. required. The lower limit of the wavelength of the radiation used for plate exposure is approximately 320 nm depending on the plate glass used in the exposure equipment.
It is limited by absorption of sub-nm wavelengths. When carbon black is used as a radiation-absorbing pigment, it has a thickness of about 1 micron so that it has an optical density of 7.0 mm to 7.0 mm for radiation in the ultraviolet and visible wavelength range. A coating is formulated and the coating is hard and has good abrasion and scratch resistance.

Graphite has a much larger particle size range than carbon graphite, i.e. 1-50 nm of carbon graphite.
K compared to 1 to 5 for the finest graphite dispersions.
It, and therefore has very poor light blocking properties compared to carbon black.

V) thus providing a coating with the required minimum optical density.
must be used in large quantities. The extremely high "toughness to binder" ratio required for graphite-based coatings compared to carbon-based coatings results in "poor adhesion", i.e., there is insufficient binder to form a cohesive coating layer. not exist. Furthermore, it is generally very difficult to obtain graphite dispersions with average particle sizes of 1.0 microns or less, whereas it is difficult to obtain graphite dispersions with average particle sizes of 0.1 microns or less. Forming the dispersion is relatively easy. Thus, 1
In coating layers with micron thickness, any oversized graphite particles protrude from the surface and are easily scraped off from the coating, causing hand and equipment stains and dust problems during exposure operations. It happens.

Thus, commercially available and other known contrast media suffer from drawbacks, and the present invention provides transparent contrast media that have good adhesion and abrasion resistance, and are clean and easy to handle. The aim is to provide a material which avoids all these problems by providing a laser which can remove coatings on film bases. Additionally, the laser contrast film of the present invention has a coating that can be completely removed when exposed to a laser beam that passes through the transparent film base.

According to this principle, (a) a heat-stable and transparent support;
(r7) a first overlay layer that is transparent and thermally decomposable and is supported on the surface of the support;
- A contrast material is provided which meets a second overlay layer which is placed on top of the overlay layer and adhered thereto.

The first and second layers may contain the same or different thermally decomposable polymeric materials, but in each case it is necessary that the first layer has good adhesion to the transparent film support. It is. Optionally, a layer consisting of superimposed layers on a film support may be further coated on top of the colored layer in order to provide the removable composite coating with certain additional heavy-duty properties, such as increased sliding properties. A layer may be applied.

The thickness of the gold side of the black colored layer and top layer is 3. Ox 10" should not exceed 3,0μ and most preferably 2.0 x 10"
It is less than 2.0μ. The graphite pigmented layer desirably has a weight ratio of carbon graphite to pyrolyzable binder of 11 to 11, preferably in the range of 8:1 to 1:8, preferably 4:1 to 1:4.
has a ratio. In practice, carbon grains vary widely in particle size and oil absorption value, and thus it is not possible to give a specific comparison; The binder to binder ratio is preferably selected to provide a hard, abrasion resistant coating with an optical density greater than 2.0.

Pyrolizable binders suitable for use alone or in admixture with others in the products of this invention include Shirl I:I-
5% solution grade polystyrene polymers and copolymers; It will be done. Also suitable are acrylic and methacrylic copolymers containing at least two of styrene, getadiene and acrylonitrile as monomers, and some vinyl homopolymers and copolymers. The suitability of this polymer component is
It needs to be established experimentally, and the above list is provided as an example and is not limited thereto.

The transparent film support preferably has good dimensional stability. This film is preferably made of polyester,
It consists of polystyrene, PVA or polycarbonate, especially polyester or polycarbonate. The most preferred material is biaxially oriented polyethylene terephthalate.

This type of polyester film is the standard film base used in photographic and photoresist products in the photographic industry. Its high degree of dimensional stability, clarity and chemical resistance make it ideal for use in the present invention. It is available in a wide range of grades, with or without treatments to promote adhesion. Suitable transparent films other than those described above may be used as well, if desired.

The energy sensitive coated film preparations of the present invention are commonly useful for applications in the graphic arts field.

These are positive or negative film watermarks.
6! Used to form D copies or lithographic printing plates. The positive and negative film watermarks produced from the coated film paulownia wood of the present invention have sufficient capacity for the passage of ultraviolet and visible light to enable their use as film masters! sometimes important.

The present invention similarly uses a transparent pyrolytic compound as a transparent 1.,°
j~ applied to the surface of the sturdy support, leaving the first layer in its entirety, and applying pyrolytic Hamura colored with carbon black to the first layer, spreading between the first layers. and forming a second layer adhered thereto.

Pigmented and pyrolyzable polymer t''1 in the overlay layer,
They are used in mixtures with modifiers to improve one or other properties of the layer. Such modifiers are selected from one or more of, for example, coalescents, resins, dyestuffs, ttJl agents, plasticizers, matting agents, lubricants and crosslinking agents. One particularly advantageous modifier prevents adhesion and the formation of Newton's rings when used on recessors. Particulate matting agents such as polymethyl methacrylate beads or matting silica.

The coating composition used to form the layer may be a solvent-based or water-based lacquer or dispersion, but is preferably a solvent-based lacquer. It may be possible to use different thermally decomposable polymers or a combination of thermally decomposable polymers of the two (or first two) coating layers, such that different coating solvents are used. solvent/
This is necessary to ensure adhesion by judicious selection of the V-coalescing grain to ensure that the first layer does not keratolyze the second layer before this layer is dried. .

This is conventionally done by appropriate selection of the solvent used. When polystyrene is used as the film support, the solvent used in the first layer must be chosen so as not to harshly attack the polystyrene film, but to ensure good adhesion between the polystyrene and overlay coating layers. To achieve this, a limited amount of solvent etching is lj 744.

In the radar-enhanced Hamura of the present invention, the thickness of the clear transparent first layer can vary within a wide range, but is preferably between 1 micron and 1.0 micron skin. The second layer colored with carbon black preferably has a thickness of 0.5μ to
It has a thickness of 2.0μ.

This first paulownia wood is made by transmitting the laser beam energy through 14 transparent supports while scanning the laser beam and changing the wavelength (this method is usually called "1/-→)-sick". ], by applying a radiation-absorbing coating appropriately.
Useful for producing contrast watermarks. The absorption of radar energy by the black pigment causes a very rapid rise in temperature, which in turn thermally decomposes the continuous phase in which the carbon particles are dispersed, pushing up the colored layer of the overlay and increasing the radar energy. Some portion of this upper layer is contained in the scanning area. Minute IJ of an unfilled transparent pyrolyzable layer with a gracque compound layer at the bottom
It is believed that this serves to ensure substantially complete removal of the blended layer of this blank from the transparent support. The reason for this is not well understood, but during the rapid and violent decomposition of the pyrolyzable binder, the particles of carbon black are forced upwardly from the support while the upper covering material is forced upwardly from the support. seems to be forced onto the surface. The formation of gaseous decomposition products at the surface of the underlying non-pigmented layer counteracts this effect, thereby reducing the residual carbon door and resulting in a sharper EA image.

During exposure, the film material coating ii is kept in intimate contact with the receptor sheet, to which the coating exposed to the laser beam is transferred. The receptor sheet exerts an important influence on the completion of image transfer. Best results are obtained when the receptor sheet is slightly porous or microscopically rough, allowing the transfer coating to embed into its surface and thus adhere strongly. . The most commonly used receptor sheets are paper and electrolyzed aluminum lithographic plates.

The attached figure is a cross-sectional view of the laser contrast imaging device in the non-exposure mode. This 4. tf==1 consists of a transparent support layer 10 of biaxially oriented polyethylene terephthalate, for example about 75μ thick. This support layer 10 is
It carries a first thermally decomposable layer 20 of, for example, polystyrene and a second thermally decomposable layer 30 of, for example, ethyl cellulose and colored with Kerrwood Blank. The pyrolyzable layers 20.30 are each approximately 1.0 micron thick. The present invention is further described by the following examples of the preparation of Lehner's '13'A resin, which is an embodiment of the invention.

Example 1 Polystyrene (BASF 5tyrol 1440)
'ff was dissolved in toluene to prepare a 5-fold fi:% solution.

This solution was coated onto a 75μ polyester film (Melinex 505) using a 7000 Meyer Rond and dried to give a coverage of 0.58 g/m2. Ethyl cellulose solution (Hercules N
4) Dispersion of carbon grain (271,1m furnace grain) in 817! I made it.

This dispersion was kneaded in a ball mill for 24 hours, and the solid content was reduced to 5 ul with an impropat tool! : :Adjusted to in%. The dispersion was then coated onto polystyrene-substituted polyester paste and dried to 1.389/m
Obtain a total dry coating weight of 2 and at the same time non, :i'
Coated with a 75μ polyester film base and 0
．． A dry coating weight of 86 &/m'' was obtained. Both coated film samples were then exposed to a YAG laser at 8 watts, power.
Imaging was performed by scanning through a polyester-based polyester-based lens. The scan rate was 1000 lines/inch, the beam diameter was 16.23 p, and the wavelength was 1.
It was set to 06μ. During scanning, the coated side of the film was kept in vacuum with an electrolyzed aluminum printer sheet. After scanning, the area of the film where the coating was removed and the cartons were transferred to the receptor seat 1 was exposed to UV light.
Their light transmittance was measured using a Macbeth densitometer with a filter attached. The results are shown below.

It was found that Sample A and Sample B were used to expose the Uv-sensitive photopolymer coating and the exposure time was used closely to the open area light transmission density when m+iji was derived from the scan. , but the negatives obtained from unsubstituted coatings are 15 to
A 20% longer exposure time was essential. In both cases the co-negative had a hard shiny surface in the unremoved areas that did not tend to smear, but the negative containing the polystyrene substitute had much better coating adhesion and abrasion resistance.

Example 2 10 of nitrocellulose (XC Kosha, DHM 10-25) in 2=1 mixture of glutyl and xylene in vinegar
The JI solution was coated onto a 75μ polyester (Melinex 542) film base using a 20,000 meter tube and dried.
rack O-A (Oiba Gei'gy) and 5urcol 86 [J(A11ied Co11o
ids Ltd) in 99% MIJ. 70
Using a 00 Meyer Ronde, this bath was then used to coat a pre-prepared nitrocellulose 1, substituted polyester film and at the same time the same sample of unsubstituted film base.

The coating weight of the AQ-colored seedlings was approximately 0.97 am2.

The coatings were scanned under the same conditions as described in Example 1.

After removal, the light transmittance for the coated film and the area of the film from which the coating was removed was measured as in Example 1 and gave the following results.

When used in subsequent exposure operations with UV-sensitive photopolymer coatings, the negatives produced from the nitrofluorocarbon film required about 10 inches less exposure time.

Example 6 i: 1 MIBK/) Polyethyl methacrylate (Co1e Polymers) in toluene
A 10% by weight solution of Ltcl, l'0olacrylp1101J) was added to 1ooo.

Coated onto Melinex 505 film base using a Meyer rod. The Grakk formulation coating lacquer of Example 1 was coated on top of the base and the apparatus (a sample of the baby base was also coated at the same time. This coating was then applied for 8 watts under the same conditions as those of Examples 1 and 2). Lede
Scanned with. The results of the same light transmission tests as those of Examples 1 and 2 are shown below.

Using negatives made from non-conductive film, exposure times were about 20% shorter and the coating was hard with good afterglow and abrasion resistance.

Those skilled in the art will appreciate that many modifications to the specific aspects and embodiments described can be made without departing from the inventive concept.
It is clear that he is capable of this. Indeed, the present disclosure is to be considered as encompassing each and every feature set forth in the paulownia timbers and methods of making them described herein, and includes disclosure number-1 representative examples set forth above. It should be read as, and is not limited to, these.

Typical modifications include the use of materials of the type described above, such as methyl meccrylate-borysterene copolymer, as a composite of the first and second overlay layers.

[Brief explanation of the drawing]

The attached figure is a cross-sectional view of the laser-contrast material. The support layer 10 carries a first thermally decomposable layer 20 and a second thermally decomposable layer 30 . Agent Akira Asamura Purification of drawings; (: (no change in 'rF) procedural amendment, (
1. Indication of the case Showa δZ patent application no. Relationship with the person making the amendment + il'l 1j, i'l applicant's address 4, agent shi, !-J 5, amendment fee l2l ("Showa, July 24, 1997, 6 , the number of inventions increases by 7, the object of sode j1-

Claims (8)

[Claims] (1) (a) a thermally stable transparent support; (b) a transparent, thermally decomposable material disposed on and adhered to the first top layer; A contrast-enhanced material containing a second overlay of 9 layers. (2) The old contrast material according to item 1 above, wherein the support is a polyester film. (3) The laser-contrast paulownia material according to item 2 above, wherein the support is biaxially oriented polyethylene terephthalate. (4) The Lehde contrast material according to any one of the above items 1 to 6, in which at least one of the first and second overlayers contains a cellulose yarn polymer. (5) The laser contrast material according to item 4 above, which is the polymer nitrocellulose or fly cellulose. (6) At least one of the 9th and second 9 layers is 7
The radar imaging method according to any one of items 1 to 5 above, which comprises a acrylic or methacrylic homopolymer or copolymer, a styrene homopolymer or copolymer, or a mixture of 11 combinations thereof. . (7) At least one of the first and second nine overlayers. Comprising an acrylic or methacrylic yarn enzymatic composite containing at least two of styrene, getadiene and acrylonide, or a mixture of these polymers, Article 2, Nos. 1 to 5
Radar as described in any one of the sections, by contrast month. (8) Any one of Items 1 to 7 of item 2, "The weight ratio of the carbon grains to the heat fraction in the 9 layers of the second upper layer is in the range of 8:1 to 1:8." Issuzou Rezu as described in . Shadow old material. (Male) The 8th above, whose weight ratio is in the range of 4:1 to 1:4
Radical contrast material described in Section 1. [theta]li The Radical contrast material according to any one of the above items 1 to 9, wherein the first coating layer has a thickness of 0.1 [mu] to 1.0 [mu]. Round: The second overlying layer has a thickness of 0.5μ to 2.0μ.
1 shadow material. 0'2 Applying a transparent, thermally decomposable first overlayer to the surface of the transparent, thermally stable support, and applying a carbon black-colored pyrolysable material to the first overlayer. The second overlay layer is applied to form a bag which is placed over and adhered to the first branch. Contrast material manufactured by the method described in any one of the above Nos. 1 to 11. IJ'] (separated from the receptor surface) is brought into contact with the receptor surface along with a bright support to image monochromatic radiation at a wavelength that is white and transparent to the support and the first overlay layer. An imaging method in which the material is irradiated and the radiation is applied in such a way as to convert selected portions of the carbon grain of the second overlying layer into a receptor surface.
The method according to item 16 above.