JPH01238657A - Thermoplastic resin film - Google Patents

Abstract

PURPOSE:To improve the anti-solvent properties and heat resistance and the dimensional accuracy of a process negative film by using a film capable of changing the permeability of the film at an infra-red region to more than the specified value by irradiating energy rays to the film, for the title film. CONSTITUTION:The film is composed of the thermoplastic resin film contg. a compd. (A) having absorption at a near infra-red region, and the photopermeability of the compd. at the max. absorption wavelength of the near infra-red region can be changed to >=30% by irradiating the energy rays such as an electron ray, etc. And, the compd. (A) is composed of a dithiol metal complex shown by the formula, etc., and the thermoplastic resin is composed of polyethylene terephthalate, etc. In the formula, M is Ni or Pd, etc., R is phenyl or alkyl group, etc. And, the film may comprise a composite film composed of a film contg. the compd. (A) and a usual thermoplastic resin film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermoplastic resin film having special absorption characteristics in the near-infrared region. More specifically, the present invention relates to a thermoplastic resin film suitable for use as a negative film for transferring complex, fine patterns, symbols, etc. onto a plate material such as a photosensitive resin.

[Prior Art] For example, in the case of liquid photosensitive resin relief printing, generally a support adhesive layer and a photosensitive resin layer are laminated in this order, and the photosensitive resin layer and negative film are brought into close contact with each other and exposed. Thereafter, the exposed areas are solidified and the unexposed areas are removed to obtain a plate.

The relatively commonly used negative films are:
Although it is made of cellulose acetate, the negative film comes into close contact with the photosensitive resin during plate making. Therefore, depending on the type of photosensitive resin, the negative film may be partially dissolved or swollen with resin monomers, etc.
Damage negative film. To prevent this, a protective film is used between the negative film and the photosensitive resin, or the negative film is embedded.

[Problems to be Solved by the Invention] However, providing such a protective layer creates a gap between the negative film and the photosensitive resin, which may cause the boundary of the transferred image to become unclear, The process of providing a protective layer is required, which also causes an increase in costs.

The present invention solves the above-mentioned drawbacks of negative films and makes it easy to produce negative films with high solvent resistance, heat resistance, and dimensional accuracy that do not cause damage due to dissolution or swelling even when brought into close contact with most photosensitive resins. The present invention provides a film or sheet (hereinafter simply referred to as a film) that can be produced in the following manner.

Means for Solving 1 Problem] The present invention provides (1) a film containing a compound having absorption in the near-infrared region, which, when irradiated with energy rays, absorbs light at a wavelength exhibiting maximum absorption in the near-infrared region; a thermoplastic resin film characterized by a transmittance change of 30% or more; A composite film comprising a layer (B) consisting of at least one resin and a compound having absorption in the near-infrared region, the composite film being irradiated with energy rays at a wavelength that exhibits maximum absorption in the near-infrared region. An object of the present invention is to provide a composite thermoplastic resin film characterized by a change in light transmittance of 30% or more.

In the present invention, thermoplastic resins include polyester, polyamide, polyolefin, polyphenylene sulfide, polycarbonate, polymethyl methacrylate, and
Refers to nostyrene, poly(styrene/acrylonitrile) copolymer, polyvinyl chloride, etc. Among these thermoplastic resins, polyester having high properties such as solvent resistance, heat resistance, and dimensional stability is preferably used. Further, among polyesters, polyethylene terephthalate is particularly preferred.

Examples of solvent-soluble resins used for layer (B) in the case of composite films include acrylic, styrene, vinyl acetate, epoxy, and polyester resins, but they may be harmful to the flammability of the solvent or the human body. From the viewpoint of safety, water-soluble polyester resins are preferably used.

Furthermore, the near-infrared region (700 to 200
Compounds with absorption at m> must not change in quality under the temperature at which they are blended with high-melting point resin and melt-molded into a film or sheet, and their absorption properties do not change at temperatures above 150'C. It is desirable that the thermal change in is as small as possible. It is also necessary to be able to write patterns and symbols on the resulting film using actinic radiation such as electron beams. Examples of compounds having the above-mentioned properties and having absorption in the near-infrared region include dithiol-based metal complexes represented by general formulas (I) and (II>).

(In formula (1), M is N i , Pd, Pt, Go, F
e, Zl,, I, A1. , I, metals such as Rh, R
represents an atom or atomic group such as phenyl, alkyl, CF3, CN, H, etc. RR The amount of the compound added to the film is preferably 0.03 to 3% by weight, more preferably 0.05 to 1% by weight, particularly preferably 0.1 to 0.5% by weight. If the amount added is less than 0.03% by weight, it will be difficult to obtain clear patterns or symbols even when irradiated with active rays, and if the amount added is 3% or more by weight, the light transmittance of the active ray irradiated area will decrease. It's low and undesirable.

In the present invention, the reason for using a compound that absorbs in the near-infrared region as described above is that, for example, when it is desired to keep information transferred to a negative film strictly confidential, it is necessary to prevent it from being easily known to the naked eye. be.

The thermoplastic resin film of the present invention may be a single film made of a mixture of the above-mentioned thermoplastic resin and a compound that absorbs in the near-infrared region, or may be a single film that does not contain such compounds (although it may contain them). of course) a normal thermoplastic resin film @ (A) and a layer containing such a compound (
A composite film consisting of B) may also be used. The embodiments of such a composite film include (B)/(A>, (B)/
(A)/(B>, (A)/(B)/(A), etc.) may be considered, but the mode is not limited in any way.

However, the configuration must be such that patterns and symbols recorded with active radiation such as electron beams can be detected.

In the case of a composite film, the layer (B) is formed from a solvent-soluble resin or a resin selected from the above-mentioned thermoplastic resins and the above-mentioned compound.

In the case of the former single film, the method of adding the compound having absorption in the near-infrared region is not particularly limited, but it is preferable to mix it into thermoplastic resin pellets and melt-mix it using an extruder.

In addition, in the case of making a composite film, the above-mentioned compound having absorption in the near-infrared region is dissolved or dispersed in a solvent together with a soluble resin and applied to a thermoplastic film, or the above-mentioned compound having absorption in the near-infrared region is dissolved or dispersed in a solvent and applied to the thermoplastic film. A method of forming a composite film by melting a thermoplastic resin containing the same type or a different type of thermoplastic resin not containing the above compound is preferably used.

In addition, in the present invention, the light transmittance of the film after irradiation with actinic rays (in the case of a composite film, the entire composite film) needs to be higher by 30% or more, preferably 50% or more, more preferably is 80% or more, particularly preferably 100% or more.

If the rate of change in light transmittance is less than 30%, for example, when making a photosensitive resin letterpress using the negative film of the present invention, when exposing the photosensitive resin with a light source such as a semiconductor laser through the negative film. , the boundary between the exposed area and the non-exposed area becomes unclear, making it impossible to obtain a good relief plate.

By irradiating the thus obtained film of the present invention with actinic rays such as electron beams to record patterns and symbols, a negative film with extremely high solvent resistance, heat resistance, and dimensional accuracy can be obtained.

Note that many of the compounds that absorb in the near-infrared region also absorb visible light, but if you want to hide the recorded patterns or symbols, you can, for example, stack a cloudy layer or print. You can also make the color change invisible.

[Measurement method] Measurement of rate of change in light transmittance: A 150 μm thick film containing a compound that absorbs in the near-infrared region (700 to 2000 nm) was partially masked, and an electron beam irradiation device Bumpgraph (manufactured by Toshiba) was used. 108r
Ad electron beam is irradiated, and the light transmittance is measured using a Hitachi 323 model spectrophotometer.

Rate of change in light transmittance (%) −((b/a>−1) xl 00 − 〇 − Here, a: Light ray at a wavelength that shows maximum absorption in the near-infrared region of the part masked against the electron beam Transmittance (%) b: Light transmittance (%) at a wavelength showing maximum absorption in the near-infrared region of the portion not masked to electron beams [Example] Examples are shown below to further explain the present invention. explain.

Example 1 0.1% by weight of bis(dithiobenzyl)nickel was added to pellets of polyethylene terephthalate having an intrinsic viscosity of 0.65, and the mixture was melt-mixed using an extruder. After drying the obtained mixture, using a normal melt biaxial stretching film forming machine,
A film was formed according to a conventional method and stretched 3.3 times in both the vertical and horizontal directions to obtain a film with a thickness of 150 μm. A part of the obtained film was masked and exposed using an electron beam irradiation device.
An electron beam of 1Q)lrad was irradiated at 000 KeV and 100 tlA. Using a spectrophotometer, the obtained sample was measured at a wavelength showing maximum absorption in the near-infrared region (in this case, 87
The light transmittance at >0 nm was measured. The light transmittance of the part irradiated with the electron beam was 50%, the light transmittance of the masking part was 22%, and the rate of change in light transmittance was 127%.

Comparative Example 1 The same operation as in Example 1 was carried out except that the amount of bis(dithiobenzyl)nickel added was 0.02% by weight,
An electron beam irradiation sample was obtained. The light transmittance of the electron beam irradiated part was 82%, and the light transmittance of the masked part was 70%.
%, and the rate of change in light transmittance was 17%.

Example 2 An electron beam irradiated sample was obtained in the same manner as in Example 1, except that the amount of bis(dithiobenzyl)nickel added was 0.05% by weight. The light transmittance of the part irradiated with electron beam is 75%, and the light transmittance of the masked part is 57%.
%, and the rate of change in light transmittance was 31%.

One plate making test - A mixture of 1 mole of trimellitic anhydride, 1 mole of maleic anhydride, and 2 moles of ethylene glycol was heated to 100% in a nitrogen stream.
The reaction was carried out at ~190'C for 3 hours to obtain an unsaturated polyester. A mixture of styrene 20C] and benzoyl peroxide added to this unsaturated polyester in an amount of 0.70% was coated on a support, the electron beam irradiated film obtained in Example 1 (NECA FILM) was layered on top of this, and then a glass film was added. I stacked the boards. A semiconductor laser beam was irradiated from the glass plate side of this laminate to solidify the unsaturated polyester and styrene mixture that overlapped the unmasked portion of the NECA film. The unsolidified unsaturated polyester and styrene mixture was removed with a solvent to obtain a relief plate with only the masked portion on the support.

The same operations as described above were carried out on the electron beam irradiated films (negative films) obtained in Comparative Example 1 and Example 2, respectively, to obtain relief plates.

When each of the letterpress plates obtained above was printed with letterpress ink, the printing results of the letterpress plates using the films obtained in Examples 1 and 2 were good, but the printing results using the film obtained in Comparative Example 1 were good. The finish of the letterpress printing was unclear.

Claims (2)

[Claims] (1) A film containing a compound that absorbs in the near-infrared region, which is characterized by a change in light transmittance of 30% or more at a wavelength that exhibits maximum absorption in the near-infrared region upon irradiation with energy rays. Thermoplastic resin film. (2) At least a layer consisting of a thermoplastic resin film (
A) and a layer (B) comprising at least one resin selected from solvent-soluble resins and thermoplastic resins and a compound having absorption in the near-infrared region, the composite film comprising: By irradiating energy rays,
A composite thermoplastic resin film characterized by a change in light transmittance of 30% or more at wavelengths exhibiting maximum absorption in the near-infrared region.