JPS61115989A - Production of polymer film showing multiple optical response - 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 Field of the Invention This invention relates to polymeric liquid crystal coatings, and more particularly to polymeric liquid crystal coatings that exhibit different optical responses in different regions of the coating.

BACKGROUND OF THE INVENTION Research on liquid crystal materials has recently become much more prevalent in the literature. Many uses for these materials have been found as optical displays.

Recently articles on cholesteric liquid crystal materials consisting of a single polymerizable moiety can be found in the scientific literature. Many articles can be found in the Soviet literature describing solution-polymerized cholesterol derivatives with liquid-crystalline properties.

However, of particular interest is the fact that cholesteric liquid crystal materials with specific optical properties have the property of being substantially fixed through a photopolymerization process. It is a recent discovery that coatings 7 can be produced whose optical response is substantially independent of temperature.

U.S. Patent No. '+50., dated December 5, 1982. Oi
l! ,! ! No. 5, and related applications describe several cholesterol derivatives Z containing an acrylate moiety in the side chain at 53 positions. Compositions consisting of these substances. Optical properties that change across the spectrum from infrared to ultraviolet? It has been found that the optical properties can be fixed by photopolymerization, and that coatings consisting of one or more optically responsive materials are disclosed in U.S. Pat. On and No. 660.278. In one embodiment, these applications first adjust the temperature to obtain the desired optical response and then selectively mask the coating so that different regions of the coating are shielded from the first photopolymerizing radiation. It describes how to do this.

The first photopolymerization step substantially fixes the optical response in the irradiated areas, but leaves masked areas uncured, thereby upon temperature adjustment.

The non-polymerized regions exhibit different optical responses. A coating is then provided in which upon re-irradiation of the structure, multiple optical responses are obtained in different regions of the coating.

Problems to be Solved by the Invention Although the aforementioned coatings exhibit unique properties, it is not necessarily desirable to obtain multiple optical responses through temperature regulation.

Means to solve problems The present invention has been made in view of the above.

The object of the present invention is to provide a photopolymerizable liquid crystal film that is characterized by being able to obtain multiple optical responses without temperature control.

Another object of the present invention is to provide a coating that provides multi-optical response and exhibits a five-dimensional optical response.

The present invention relates to a polymeric cholesterin liquid crystal coating that is obtained without changing temperature during a one-component polymerization process and exhibits multiple optical responses. By selectively photopolymerizing some regions 7 of the coating at different rates than other regions, a coating exhibiting a differential, fixed optical response 2 is obtained.

In one aspect, the present invention provides a coating comprising a photopolymerizable cholesteric liquid crystal monomer material; at least a portion of the coating is optically responsive. selectively aligning the portions as shown; and subjecting the coating to sequential photopolymerizing irradiation under conditions such that predetermined regions of the coating polymerize at a different rate than other regions, the cured coating exhibits differential ( Differential) Fixed optical response? The present invention relates to a method for forming a polymer wave film having a fixed optical response, which comprises a step of forming a polymer wave film having a fixed optical response.

In a second embodiment, the invention relates to a photopolymerized cholesteric liquid crystal coating having a differential, fixed optical response, the coating being polymerized under conditions such that certain areas of the coating polymerize at a different rate than other areas. It is obtained by sequentially irradiating the coating for photopolymerization.

Function The monomers used in the practice of this invention have photopolymerizable side mi
x and is a cholesteric liquid crystal material that exhibits a desired optical response within the visible spectrum. Preferred monomers are described in U.S. Patent Application No. 1150. Ogl! However, these substances can be used as single monomers, mixed monomers, or mixtures of monomers and other polymerizable or non-polymerizable, non-intermediate substances. It is something.

Invention? To carry out, a composition consisting of a photopolymerizable cholesteric liquid crystal monomer, a photoinitiator and optionally other monomers, intermediate or non-intermediate substances and/or a non-intermediate, non-polymerizable diluent. is prepared. The composition is then prepared as a coating.

The temperature is brought to such a level that the coating exhibits the desired optical response. The coating is then photopolymerized such that certain areas cure at a different rate than other areas. This can be accomplished in a variety of ways.

As an example, polymerization of the surface is carried out in the presence of oxygen, which tends to exhibit photopolymerization reactions as is well known. When the coating is placed over a negative thermal coating that selectively shields the polymerizing radiation, no curing occurs in the shielded areas, but curing occurs in the areas that the mask does not shield from the coating radiation. Nevertheless. The surface in exposed areas will be incompletely cured due to oxygen suppression.

The interior of the exposed area is completely cured. Next, when the mask is removed and the surface thoroughly flushed with nitrogen or other inert gas, a difference in optical response is seen on the surface of the coating. Pre-shielded regions tend to exhibit one optical response 7, while unshielded oxygen-suppressed regions exhibit a different color.

Another example is irradiation for photopolymerization under an inert atmosphere with 6 surfaces partially shielded? The unshielded morsels are then fully cured.

The mask is then removed and a mixture of nitrogen and oxygen is applied near the uncured surface, which is subjected to photopolymerizing irradiation to produce different cure rates. After final curing in an inert atmosphere, a significant color difference is observed between the first and subsequent cured areas.

Combining the above methods, dimensional effects can also be produced by using two different masks. For example, a first mask is placed over the coating (or film) and irradiated in air to the zeroth order. Next, the mask is removed and the entire membrane surface is irradiated in air. A second mask is placed over the coating and irradiated under an inert atmosphere. And then this mask! The entire coating is removed and irradiated under an inert atmosphere. The result is a dimensional image! The membrane shown is obtained.

Different curing rates can also be obtained by applying high intensity radiant energy to the -S portion of one surface and applying 2 low intensity radiant energy to other parts of one surface, although in an overall inert atmosphere. Since different photopolymerization rates are achieved in these different regions, the resulting products exhibit different optical responses.

The invention may be more clearly understood by reference to the following examples, which are provided by way of illustration (and not limitation).

EXAMPLES In the following examples, U.S. Patent Application No. 1+50. Compounds corresponding to the acrylate derivatives Va and Ve described in the OH issue were used to prepare JI+:f+i:body membranes. Do these compounds have the following structures? In the above formula, A=R1=(CH2)n. For compound Vfi, n=10. and for compound ve, n=5.
and y==Q for both compounds.

Example 1 Compound *V Each k of a and ve is 47% by weight.

5% by weight of pentaerythritol triacrylate crosslinking diluent, 2% by weight of benzophenone photoinitiator, and trade name I
A composition consisting of 1% by weight of rgacure 651 photoinitiator was prepared. Irgacure G 51ha2
, 2-dimethoxy-2-phenyl-acetopheno/.

Its composition is completely melted at 953°C (2007),
It was left to cool until wet. And α0051cr on Mylar film at room temperature! Stretched to a thickness of I (0,002 in). The non-polymerized material appeared blue-green at a 90 degree (specular) viewing angle.

The stretched coating is placed in a chamber, where portions of the surface are covered with a selectively shielding negative, and the chamber is partially flushed with nitrogen.
Lashing left some residual oxygen. The masked coating was then imaged by applying 150 joules of ultraviolet energy (ie, 5 watts/m for 50 seconds). The image had a yellow-green color in the exposed area at specular observation intensity. Next, I opened the room, removed the mask,
The chamber was closed again and thoroughly flushed with nitrogen to remove all oxygen. Next, 500 Joules of energy (i.e., 5 Watts/cd) was applied to the entire coating.

60 seconds) to allow complete polymerization of the coating. Is the polymerized film a yellow-green image when viewed at a specular angle? Contains a blue-green background.

Example 2 Compounds Va and Ve'a' 111125% by weight each, 5% by weight pentaerythritol triacrylate crosslinking diluent, Irgacure 651 0.5
% by weight and a membrane was prepared as in Example 1 (with a blue-green appearance). The membrane was covered with a selectively protective negative in some areas and the first masked membrane was exposed to 150 dinyers of radiant energy (i.e., 5
Watt/d for 30 seconds) to obtain a partially cured film.

The membrane had a yellow-green color7 in the exposed areas.

The negative was then removed from the film and the entire film was exposed to 50 Joules of radiant energy (57 joules/d for 10 seconds) in air. Following the second exposure, the film was selectively masked in different areas of the film with a second negative, and the film was placed in a nitrogen chamber and thoroughly flushed with nitrogen. Apply 150 joules of radiant energy (5 W/d for 50 seconds) to the film and take an image? Obtained. The image was blue-green in the final exposure at specular viewing angles.

The second negative was removed and the entire film was subjected to 300 Joules of radiant energy (60 seconds at 5 Watts/al) in a fully flushed nitrogen chamber to fully polymerize the film.

At a viewing angle of 90 degrees, the first image appeared on top of the second image. That is, it had a 5-dimensional effect. At a viewing angle of lj5, the second image appeared on top of the first image. In both cases, the first image appeared as a light yellow-green color, the second image appeared as a blue-green color, and the background became a dark yellow-green color.

The present invention is not limited to one or more of the descriptions and illustrations, but includes all changes and modifications contemplated by the claims.

Claims (1)

[Claims] 1. Providing a coating made of a photopolymerizable cholesteric liquid crystal monomer material; selectively aligning at least a portion of the coating such that the aligned portion exhibits an optical response; and exposing said coating to sequential photopolymerizing radiation under conditions such that predetermined areas of said coating are polymerized at a different rate than other areas such that the cured coating exhibits a differential, fixed optical response. A method for producing a polymer film having a fixed optical response, characterized in that: 2. The method comprises the steps of sequentially exposing the coating to photopolymerizing radiation while selectively shielding portions of the coating from the radiation, and the exposing to the photopolymerizing radiation covers a surface of the coating. 2. The invention as claimed in claim 1, wherein the method is carried out at a substantially constant temperature while selectively varying the oxygen content of the atmosphere adjacent to the atmosphere. 3. The above sequence comprises: (a) providing the coating with a first mask and irradiating the masked coating under an atmosphere comprising oxygen; (b) removing said first mask and irradiating said coating under an atmosphere comprising oxygen; (c) providing said coating with a second mask and irradiating said masked coating under an inert atmosphere. and (d) removing the second mask and irradiating the coating under an inert atmosphere. 4. The invention according to claim 1, wherein the coating is selectively exposed to photopolymerizing radiation of various intensities. 5. Light having a differential, fixed optical response obtained by sequentially exposing a cholesteric liquid crystal coating to photopolymerizing radiation under conditions such that certain areas of the coating are polymerized at a different rate than other areas. Polymerized cholesteric liquid crystal coating. 6. The coating is sequentially exposed to photopolymerizing radiation with portions of the coating selectively shielded from the radiation, the radiation selectively altering the oxygen content of the atmosphere adjacent the surface of the coating while substantially The invention according to claim 5, characterized in that the process is carried out at a constant temperature. 7. The invention as set forth in claim 6, wherein the film is composed of a three-dimensional image. 8. The invention according to claim 5, wherein the coating is obtained by selectively exposing the coating to photopolymerizing radiation of various intensities.