JPH0587397B2 - - Google Patents

Description

[Detailed description of the invention]

(A) Industrial Application Field The present invention relates to a photocurable biocapsule whose destruction can be controlled. (B) Conventional technology and its problems Conventionally, so-called microcapsules enclose liquid, solid, or gas as fine particles with a size of 1 μm to several hundred μm, and are uniformly surrounded by a thin film of several μm to several μm. It is based on a U.S. patent.
Since it was disclosed in the specifications of No. 2711376 and No. 712507, it has come to be used for various purposes. The most common application is pressure-sensitive recording paper. That is, microcapsules encapsulating a coloring agent solution in which a coloring agent, which is a colorless electron-donating dye precursor, is dissolved in a non-volatile solvent, are coated on the back side of the support, and a colorless color is coated on the surface of the upper paper and another support. When the bottom paper coated with a color developer, which is an electron-accepting acidic substance, is stacked so that the coated sides of each paper are facing each other and pressure is applied, the microcapsules are destroyed and the contents are released, and the color developer and color developer are combined. A colored substance is formed on the surface of the lower paper by a chemical reaction upon contact with the agent, and this is what is obtained as a copy image. In this way, microcapsules can simultaneously confine a substance with certain properties by forming a thin film on the outside of the substance, and when necessary, the substance can be extracted by breaking the thin film. . On the other hand, when microcapsules are broken to release the contents, the degree of destruction can be freely controlled as needed, and photocurable microcapsules can be left undestructed, partially destroyed, or completely destroyed. be. This is a photocurable microcapsule that mainly contains a photocurable resin and a photopolymerization initiator, and the destruction of the microcapsule is controlled by light. The present inventors previously filed an application for photocurable microcapsules in JP-A-58-14943, and used the known phase separation method (U.S. Patent Nos. 2800457 and 2800458) as the microencapsulation method, and Legal (Special Publications No. 38-19574, No. 446-42, 771-1971)
No.), in situ method by polymerization of monomers (Special Publication No. 36
-9168, JP-A-51-9079), melting and dispersion cooling method (British Patent No. 952807, British Patent No. 965074), and spray drying method (US Patent No. 3111407, British Patent No. 930422). The present inventors further investigated capsules produced by a microencapsulation method that is simpler and lower in cost than the above-mentioned known microencapsulation methods. In JP-A-58-107189, as a method for increasing the lipid content of growing microorganisms, a growing microorganism (for example, oleaginous yeast, beer yeast, etc.) with a lipid content of 10 wt% or more collected from a culture medium is injected with an organic substance for increasing the lipid content ( For example, microbial capsules are mentioned in which a liquid selected from aliphatic alcohols, esters, aromatic hydrocarbons, hydrogenated aromatic hydrocarbons is ingested. However, in the above-mentioned microorganism capsule, it must be a growing microorganism, that is, a growing microorganism that has the ability to proliferate when a medium is provided, and the lipid content must be
Since it had to be 10wt%, we had to focus on managing and preserving the growing microorganisms and maintaining the lipid content. (C) Object of the Invention The present invention is to provide a simple and low-cost photocurable biocapsule. (D) Structure and operation of the invention The present invention is a photocurable biocapsule characterized in that a photocurable resin and a photopolymerization initiator are mainly ingested by microorganisms such as fungi. More preferably, the photocurable biocapsule is characterized in that the fungus is yeast. The photocurable biocapsule as used in the present invention is made by ingesting or encapsulating mainly a photocurable resin and a photopolymerization initiator into microorganisms such as fungi, particularly yeast. In the classification of fungi, there are two types of yeast: spore-forming yeast, which belong to the Ascomycetes, and non-spore-forming yeast, which belong to Deuteromycota. Saccharomycetoideae for spore-forming yeast [Saccharomycetaceae]
Subfamily (this subfamily includes the tribe Saccharomyceteae, including the genus Saccharomyces, genus Schwaniomyces, genus Debaryomyces, genus Saccharomycopsis, etc.) , as part of the Nadosoneae family, including the genus Saccharomycodes), and the subfamily Lipomycetoideae (within this subfamily, the genus Lipomyces). Nonspore-free yeasts (Cryptococcaceae) include the subfamily Cryptococcoideae (this subfamily includes Cryptococcus).
Genus, Brettanomyces,
(Genus Candida, Genus Kroeckera, etc.) Subfamily Trichosporoideae (This subfamily includes the genus Trichosporon). More specifically, S. cervisiae of the genus S. cervisiae, S. rouxii of the genus S. rouxii, S. carlsbergensis, endo of the genus Endomyces E. vernalis, L. lipofer of the genus Lipomyces, L. starkeyi, T. pullulans of the genus Trichosporon, Trichosporonctaneum T.cutaneum], Candida curvata [C.curvata],
C. utills, C. tropicalis, C. flaveri, and R. glutinis of the genus Rodotorula can be mentioned. can. The yeasts exemplified above include so-called oleaginous yeasts with a high lipid content and yeasts with a low lipid content, and both can be used in the present invention. The present invention uses these yeasts to infiltrate a mixture mainly consisting of a photocurable resin and a photopolymerization initiator into the yeast by diffusion from the yeast cell wall without destroying the cell wall. The yeast used is 10wt with low fat content.
It has been found that it is possible to ingest (internalize) even if the amount is less than %. In addition, yeast that has a proliferation function (active) can be used, but in particular, inactive yeast that does not have a proliferation function can take in (encapsulate) the photocurable resin and photopolymerization initiator in a shorter time. I found out. This has the advantage that it does not require such strict storage, whereas yeast with a growth function requires closed low-temperature storage in order to maintain its function. The yeast used in the present invention has various shapes such as oval, circular, lemon-shaped, columnar, and oval, but preferably circular, oval, and oval. Also, the diameter of yeast varies depending on the type, but 5
~20 μm is preferred. During the encapsulation of the present invention, the temperature is between 35 and 70°C.
℃, preferably 40-60℃. The time is 30 minutes or more, but it can be changed as appropriate depending on the amount to be ingested (internalized). The ratio (weight) of the substance to be ingested (incorporated) to the yeast is 2 or less, preferably 1 or less per yeast. Next, the photocurable biocapsule using the above-mentioned yeast will be described in more detail. The destruction of the biocapsule can be freely controlled by light by ingesting (encapsulating) a photocurable resin and a photopolymerization initiator into yeast. When it is desired to remove the contents, the cell wall can be destroyed by applying pressure, heat, etc. from the outside in the same way as with ordinary microcapsules, and the contents can be released. In addition, when it is desired to keep the inclusions in the capsule as they are, when the biocapsule is exposed to light, the light that passes through the cell wall hardens the photocurable resin that is the inclusion, turning it into a hard resin. As a result, the photocurable biocapsule becomes a capsule that is more rigid than the inside, and will no longer be destroyed even when subjected to an external impact, and the contained substances will no longer be released. Furthermore, the release of inclusions can also be controlled by the amount of light. The photocurable biocapsule of the present invention must necessarily contain a photocurable resin and a photopolymerization initiator, but it can also contain any other substance. Examples include, but are not limited to, agricultural chemicals, foods, cosmetics, catalysts, adhesives, curing agents, oxidizing agents, reducing agents,
Organic substances used in dyes, pigments, plasticizers, polymer flocculants, rust preventives, antioxidants, soil conditioners, etc.
Inorganic substances and the like can be contained in the inclusions in a solid or liquid state. The photocurable biocapsule of the present invention can be widely used in various fields. For example, if a reactive substance is added to a part of the contents of a photocurable biocapsule, and the capsule is coated on a support and then exposed to light, the degree of curing of the capsule will vary depending on the amount of exposure, and the content of the capsule will change. The capsules with different release amounts are produced.
It can then be used as an optical sensor that can display the amount of exposure in terms of color shading by stacking it on a support coated with a co-reactant that reacts with the reactive substance to form a colored substance and applying pressure at a constant pressure. When a support coated with photocurable biocapsules containing the same substance is exposed overlappingly with an original, the imaged areas of the original remain as they are because no light passes through or reflects the capsules. Since the portion is exposed to light, the capsule hardens from the inside. After that, when an image-receiving sheet coated with a co-reactive substance is placed and pressed, a copy of the original is obtained on the image-receiving sheet, and it is also used as a copying material that can make multiple copies, but is not limited to this. Instead, any product that can utilize the functions of photocurable biocapsules can be used freely. The photocurable resins included in the photocurable biocapsules used in the present invention include cinnamic acid residues, cinnamylidene residues, α, β-unsaturated ketone residues, coumarin residues, anthracene residues, Photodimerizable resins with photosensitive groups such as enylmaleimide residues, benzophenone residues, stilbene residues, diazonium salt residues, quinonediazide residues, azide residues,
Photodegradable resins with photosensitive groups such as dithiocarbamate residues and benzoin residues, photopolymerizable resins with acryloyl groups, allyl groups, vinyl groups, epoxy groups, etc. can be optionally used, but photopolymerizable resins are particularly suitable. It is valid. As for the shape, a liquid one is advantageously used. In addition, as a polymerization initiator for polymerizing the photocurable resin, commonly used known compounds may be used, such as benzoin alkyl ether, benzophenone, Michler ketones, thioxanthone, acetophenones, etc. For example, anthraquinone, 5-nitrofluorene, etc. are used as photosensitizers that have the effect of broadening the sensitive wavelength range, and fixatives such as radical polymerization inhibitors, modifiers, and relatively low molecular weight are used to improve storage stability. In some cases, diluents such as oligomers or monomers may be included at the same time. At the same time, in order to improve the solubility of the substance to be encapsulated, a high-boiling point oil-based solvent,
For example, alkylnaphthalenes, alkylbiphenyls, alkyldenbiphenyls, esters, and the like are sometimes used as solubilizing agents, but it is inappropriate to use them in large amounts because they adversely affect the degree of curing. Ultraviolet light is generally used as light for curing the photocurable biocapsules used in the present invention. As the light source, sunlight, xenon lamps, low pressure and high pressure mercury lamps, etc. are used. There is little degradation in the properties of the photocurable biocapsules during manufacturing and normal handling time, such as exposure to light such as occurs with room lights or indirect sunlight. (E) Examples The present invention will be explained in more detail with examples. Example 1 0.25% surfactant (trade name Adecatol LO
-15, produced by Asahi Denka Co., Ltd.) in 450 parts of water, 80 parts of epoxy acrylate photocurable resin (product flavor Lipoxy, produced by Showa Kobunshi Co., Ltd.) and benzoin ethyl ether.
Add 0.2 parts of the mixture to a homogenizer to reduce the particle size.
It was emulsified until it became around 1 μm. This emulsion was heated to 50℃.
The emulsion was kept in a constant temperature bath, and stirring was continued using a stirrer until the temperature of the emulsion reached 50°C. Separately, Saccharomyces cerevisiae (baker's yeast) is a dry yeast with no growth function.
100 parts of the sample were weighed out and gently added to the emulsion maintained at 50°C while stirring. Note that the lipid content of the yeast used was approximately 9 wt%. When the yeast was sampled 30 minutes after addition and observed under an optical microscope, a bright sphere could be seen in the center of the yeast. However, emulsified particles were still observed at this point. The mixture was further stirred for 3 hours and then allowed to cool. When the yeast was observed again using an optical microscope, 30 minutes later, there was a large shiny sphere in the center of the yeast, and no emulsified particles could be observed.
20 parts of a 10% polyvinyl alcohol aqueous solution and 20 parts of water were added to 60 parts of the aqueous dispersion of the obtained photocurable biocapsules, thoroughly stirred, and then coated on a base paper having a basis weight of 50 g/m ² using a Meyer bar. Black paper was applied to a portion of the photocurable biocapsule coated surface, and xenon light was exposed five times from the coated surface side using a Resorxenofax FX-150. After removing the black paper and applying pressure to the entire surface with a pressure roll, we observed the exposed and unexposed areas with an electron microscope.The capsules in the exposed areas were not destroyed and remained spherical, but the unexposed areas were It was confirmed that all of the capsules had been destroyed. Example 2 Encapsulation was carried out in the same manner as in Example 1 except that Saccharomyces cerevisiae (baker's yeast) was used as an active yeast capable of multiplying dry yeast. It took 5 hours before I was able to see a shiny ball in the area. Furthermore, in the same manner as in Example 1, non-destruction of the capsule in the exposed area was confirmed. Example 3 In Examples 1 and 2, the effect of the prepared photocurable biocapsules was confirmed using an electron microscope, but this example is an example in which visual confirmation was performed by incorporating a colorless dye. Instead of the mixture of 80 parts of epoxy acrylate photocurable resin and 0.2 part benzoin ethyl ether in Example 1, 80 parts of oligoester acrylate photocurable resin (trade name: Aronix, manufactured by Toagosei Kagaku Kogyo Co., Ltd.), A photocurable biocapsule dispersion was prepared in the same manner except that a mixed solution of 3 parts of crystal violet lactone and 0.2 parts of benzoin ethyl ether was used. 60 parts of the dispersion
After adding 20 parts of 10% polyvinyl alcohol aqueous solution and 20 parts of water and stirring thoroughly, use a Meyer bar to reduce the basis weight to 50.
g/m ² of paper. The coated surface of this photocurable biocapsule sheet was flash-exposed to xenon light one to five times using a Resorxenofax FX-150. 3. An image receiving sheet coated with a mixed dispersion of 5-di-tert-butylsalicylic zinc oxide was stacked so that the coated surfaces faced each other, and pressure was applied to the entire surface with a pressure roll. As a result, red colored images with different densities were obtained. Table 1 shows the relationship between the number of flash exposures and the red color density obtained on the image receiving sheet.

【table】

[Table] Table 1 shows that when the photocurable biocapsules containing reactants are not exposed to light, they are completely destroyed and a highly concentrated colored image is obtained on the image receiving sheet, but by increasing the number of exposures, the biocapsules harden. As the process progresses, the number of biocapsules destroyed decreases. For this reason, the color density decreases with the number of exposures, and when the biocapsule is completely cured and becomes a rigid capsule, it will no longer be destroyed. Therefore, it can be seen that no color develops on the image-receiving sheet. (F) Effects of the Invention As described above, the photocurable biocapsule of the present invention is a capsule produced by a simple and low-cost method using microorganisms such as fungi, particularly yeast, and has great industrial significance.

Claims (1)

[Scope of Claims] 1. A photocurable biocapsule characterized in that a photopolymerization initiator is mainly ingested by yeast microorganisms. 2. The photocuring type according to claim 1, wherein the yeast is a spore-bearing yeast selected from the group of the genus Satucharomyces, the genus Schwaniomyces, the genus Debaryomyces, the genus Satucharomycopsis, and the genus Satucharomycodes. biocapsule. 3 Spore-bearing yeast consisting of the genus Satucharomyces is
The photocurable biocapsule according to claim 2, which is at least one member selected from the group of Saccharomyces cerevisiae, Saccharomyces carlsbergensis, and Saccharomyces sulxi. 4. The photocurable biocapsule according to claim 1, wherein the yeast is a non-sporulating yeast belonging to the group Cryptococcus, Bretsutanomyces, Candida, Chloechera, Trichosporon, and Rhodotorula. . 5. The photocurable type according to claim 1, wherein the nonspore-free yeast belonging to the genus Candeida is at least one species selected from the group of Candeida curverta, Candeida tailus, Candeida tropicalis, and Candeida fleveri. biocapsule. 6. The photocurable biocapsule according to claim 4, wherein the Trichosporon genus is Trichosporonctaneum.