WO2006022255A1 - Process for producing microcapsules and microcapsules, and magnetic display medium using the same - Google Patents

Abstract

This invention provides a process for producing microcapsules, which can produce microcapsules having no significant film swollen tendency without using aldehydes, and microcapsules produced by the process. This production process of microcapsules is a process for producing microcapsules having a protein film using a complex coacervation method and is characterized in that, in curing a coacervate film, a water-soluble polymer compound having an electric conductivity of 0.005 to 1.2 S/m as a 10 wt% aqueous solution, or a water-soluble polymer compound selected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, and their mixtures is allowed to coexist. The microcapsules thus produced contain any of the above water-soluble polymer compounds in their film part. These microcapsules are useful, for example, for magnetic display media.

Description

 Specification

 Microcapsule manufacturing method, microcapsule and magnetic display medium using the same

 Technical field

 [0001] The present invention relates to a method for producing a microcapsule and a microcapsule produced thereby. More specifically, it is a method for producing a microcapsule using a complex 'coacervation method, in which a specific water-soluble high-molecular compound is allowed to coexist at the time of producing the microcapsule, and a protein as a coating. The present invention relates to a microcapsule containing a specific water-soluble polymer compound.

 The present invention further relates to a recording material such as a magnetic display medium comprising such a microcapsule.

 Background art

 [0002] Conventionally, microcapsules have been applied to various uses, and many proposals have been made regarding their production methods. Among them, the complex coacervation method is one of the microencapsulation methods applied industrially.

[0003] The general complex 'coacervation method is to manufacture a microphone mouth capsule by the following process.

 (1) Disperse the core material (oil-based material) in an aqueous solution containing the coating material (polycation) to obtain oZw emulsion in which oil droplets are dispersed in the aqueous solution.

 (2) Add the polyion to the emulsion and mix, and add the acid to adjust the pH to about 3-5. As a result, coacervation occurs and a coacervate film is formed.

(3) The temperature of the coacervate droplet is reduced at a low temperature, and the coating is cured (cross-linked and Z or modified) by adding a curing agent.

[0004] Aldehydes such as formaldehyde and dartalaldehyde are generally used as a curing agent for the microcapsule film by such a method. However, aldehydes are effective curing agents, but it is not preferable to use them from the viewpoints of toxicity and environmental considerations. Both formaldehyde and dartalaldehyde are designated as PRTR Class 1 In particular, formaldehyde has been suspected of being a causative agent of sick house syndrome in recent years, and is also regarded as an emission-regulated substance as a volatile organic compound (hereinafter referred to as VOC). .

 [0005] For this reason, various studies on hardeners that replace aldehydes have been made! A typical example is transdaltaminase (Patent Documents 1 to 3). However, according to the study by the present inventor, the gelation of the coacervation of the protein film and the coacervate film needs to be performed in the acidic region, that is, at a low pH, whereas the hardening of transglutaminase. The reaction must be carried out at a relatively high pH of 5-9! In such a high pH range, the protein film significantly swells, resulting in distortion of the shape due to capsule volume expansion, thickening of the capsule dispersion during the manufacturing process, reduced processability after encapsulation, core material Problems such as a decrease in retention capacity may occur.

[0006] Techniques for preventing such swelling of the film have also been studied (Patent Document 4 or 5). These methods are examples using the salting-out method, which is a kind of orifice method or simple coacervation method, and in order to suppress the swelling of the film when the film is cured with transdaltaminase. Electrolytes such as acid salts, metaphosphates, sulfates and acetates coexist. In the simple coacervation method, after the core material is emulsified and dispersed in a solution in which the film material is dissolved in a good solvent, the solubility of the film material is reduced by adding a poor solvent such as salt or film material. In this method, a wall film is formed around the core material. On the other hand, the complex coacervation method is a method for forming a wall film by an electrical interaction using a polycation and polyion as a coating material, and thus is greatly different as a manufacturing method. In addition, when an electrolyte as described above is used, it may be necessary to remove the electrolyte (desalting step) before using the microcapsules. That is, when the microcapsule is used as a display medium such as a magnetic display medium or a heat-sensitive recording material, when the microcapsule capsule is applied and arranged on the support, the microcapsule dispersion is applied as it is on the support. When dried, the! /, Salt, etc. may precipitate as a solid in the display medium, which may adversely affect the visibility of the display medium. In such a case, it is common to remove the salt by a desalting step. Furthermore, the complex coacervation method is not necessarily a suitable method because it needs to be added after film formation. [0007] In addition, a method using a nonionic water-soluble polymer compound as an additive has been studied in order to enable the complex coacervation method to be performed in a wide pH range.

(Patent Document 6). In this method, the suppression of swelling at the time of curing of the force film to which various nonionic water-soluble polymer compounds are added is mentioned.

[0008] On the other hand, a magnetic display medium using microcapsules has also been studied (Patent Document 7). However, these materials use micro force capsules manufactured by conventional methods, and microcapsules containing harmful aldehydes are generally used.

 Patent Document 1: Japanese Patent Laid-Open No. 10-249184

 Patent Document 2: Japanese Patent Laid-Open No. 02-086741

 Patent Document 3: Japanese Patent Laid-Open No. 05-292899

 Patent Document 4: Japanese Patent Laid-Open No. 09-248137

 Patent Document 5: JP 2000-079337

 Patent Document 6: Japanese Unexamined Patent Publication No. 57-171432

 Patent Document 7: Japanese Unexamined Patent Application Publication No. 2001-075510

 Disclosure of the invention

 Problems to be solved by the invention

[0009] The present invention provides a method for producing a microcapsule that does not use a highly harmful aldehyde that has been conventionally used and is suitable for a display medium such as a magnetic display medium and has a small film swelling. Is intended to provide.

 Means for solving the problem

 [0010] The method for producing a microcapsule according to the present invention is such that, when producing a microcapsule having a protein film using a complex 'coacervation method, the electrical conductivity when a 10 wt% aqueous solution is used is 0.005- 1. It is characterized by the coexistence of a 2SZm water-soluble polymer compound.

[0011] In addition, another method for producing microcapsules according to the present invention includes the production of a microcapsule having a protein film using a complex 'core cell basing method, and polybutyl alcohol, polybutylpyrrolidone, polyethylene oxide, and the like. And a water-soluble polymer compound selected from the group consisting of a mixture thereof and a mixture thereof.

 [0012] Further, another method for producing a microcapsule according to the present invention is that in the above method, the curing agent for the protein film is transdaltaminase.

[0013] In addition, the microcapsule according to the present invention includes a film containing a protein and a water-soluble polymer compound having an electric conductivity of 0.005 to 1.2 SZm when a 10 wt% aqueous solution is used. , Is characterized by.

[0014] Further, in another microcapsule according to the present invention, the film has a protein, polyvinyl alcohol, polybutylpyrrolidone, polyethylene oxide, and derivatives thereof.

And a water-soluble polymer compound selected from the group consisting of mixtures thereof.

Furthermore, a magnetic display medium according to the present invention comprises the above microcapsule.

, Is characterized by.

 The invention's effect

 [0016] According to the present invention, it is possible to produce a microcapsule with less shape expansion and distortion without using a highly harmful aldehyde that can cause sick house syndrome as a VOC. By using the microcapsules obtained by this method, it is possible to form a display medium or recording material that does not contain harmful substances and has excellent resolution.

 BEST MODE FOR CARRYING OUT THE INVENTION

[0017] Manufacturing method of microcapsule

 The method for producing a microcapsule according to the present invention uses a complex 'coacervation method', and is characterized in that a water-soluble polymer compound is allowed to coexist when a protein film is cured (crosslinked and z-modified). The method of the present invention will be described in accordance with the order of the production process as follows.

 [0018] First, a core substance (oil-based substance) is dispersed in an aqueous solution containing a film substance to form an oZw emulsion in which oil droplets are dispersed in the aqueous solution.

[0019] The core material to be used is arbitrarily selected according to the target microcapsule. example Examples thereof include pressure-sensitive adhesives, adhesives, and coloring materials. It is also possible to use a display medium element or the like, for example, an oily substance containing fine magnetic particles of a magnetic display medium or the like as a dispersion, or a heat-sensitive recording material that changes color by heating. In addition, foods, pharmaceuticals, quasi-drugs, fragrances, detergents, etc. that are immiscible with water can be used as the core substance.

 [0020] As the coating substance, a hydrophilic colloid having an isoelectric point as a polycation and capable of gelling is used, and a water-soluble protein is generally used. More specifically, gelatin, agar, casein, soy protein, collagen, albumin and the like can be mentioned. Of these, gelatin such as acid-treated gelatin and alkali-treated gelatin is preferred, and acid-treated gelatin is most preferred.

 [0021] In order to disperse the core substance in the aqueous solution containing the coating substance, it is possible to add a core substance to the aqueous solution and use a method such as stirring or ultrasonic irradiation. The concentration of the core material and the coating material is arbitrarily selected according to the properties and shape required for the target microcapsule. In addition, the size of the core material droplet obtained by the dispersion is related to the size of the micro force capsule finally obtained. The size of the microcapsules is selected according to the purpose, and the size of the emulsion droplets is substantially reflected as the particle size of the microcapsules. The final size of the microcapsule, specifically the diameter in terms of a sphere, is generally 0.1 to 3000 / zm, preferably ί or 0.1 to 2000 111, and more preferably 0.1 to LOOO / zm. Dispersion is performed to obtain oil droplet force S according to

 Subsequently, Polyon is mixed with the obtained OZW emulsion to make it uniform, and then the pH is acidified to form a coacervate film.

[0023] The polyone used is a force selected as necessary. Specifically, gum arabic, sodium carboxymethylcellulose, sodium alginate, sodium polyvinylbenzene sulfonate, polyvinyl methyl ether / maleic anhydride copolymer, etc. Is mentioned. Of these, gum arabic and sodium carboxymethyl cellulose are preferably used. Among them, gum arabic has a tendency to be slightly inferior in its ability to form a coacervate film against emulsions with a relatively large particle size of 100 m or more. Carboxymethyl cellulose sodium has such a large particle size. U, especially preferred because it can easily form a sufficient coacervate film for the emulsion. [0024] After the polyion is mixed, the pH of the emulsion is adjusted to an acidity, for example, pH 3 to 5, preferably 4 to 4.5. As the acid used at this time, it is preferable to select an acid which does not impair the properties of the core material and the coating material. In general, organic acids such as acetic acid, succinic acid, succinic acid, oxalic acid, lactic acid and salicylic acid, and inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid are used.

 [0025] The emulsion on which the coacervate film is formed is subsequently cooled in order to gel the film. Usually, the emulsion is cooled to 5 to 25 ° C., preferably 5 to 10 ° C. to gel the skin.

 [0026] In order to cure the gelled film, a hardener is subsequently mixed into the emulsion. Examples of the hardener include conventionally known hardeners such as transglutaminase, formaldehyde, dartalaldehyde, amyoban, gallic acid, and tannic acid. Of these, aldehydes such as formaldehyde and dartal aldehyde are not preferably used from the viewpoints of toxicity and environmental considerations. Both formaldehyde and dartal aldehyde have been designated as PRTR Class 1 Designated Chemical Substances. Formaldehyde, in particular, has recently been suspected of being a causative agent of sick house syndrome, and is also subject to emission control as VOC. It is positioned in

 [0027] Generally, it is preferable to use a curing agent that has low toxicity and a low environmental burden as a curing agent. Specifically, it is preferable to use transglutaminase, myoban, gallic acid, tannic acid, or the like. . Curing agents such as myoban, gallic acid, and tannic acid are also problematic in terms of toxicity and environmental load, but it is particularly preferable to use transdaltaminase from the viewpoint of insufficient curability and odor. . Since transdaltaminase is an enzyme that exhibits neutrality, specifically high pH activity in the region of pH 5-9, the curing reaction using transdaltaminase is pH 5-9, preferably 6-8. It is common to do this. Even when aldehydes are used as curing agents, the pH needs to be alkaline, specifically, pH 9 or higher in order to allow rapid reaction.

 [0028] After the coating is cured in this way, the desired microcapsules can be obtained by operations such as filtration, decantation, and drying as necessary.

[0029] The method for producing a microcapsule according to the present invention is characterized in that a water-soluble polymer compound is allowed to coexist in the above-described complex 'core cell basis method. Especially the core If the film is cured by adjusting the pH after forming the rubeto film, the water-soluble polymer compound is introduced into the system before the pH is changed to the desired reaction conditions. It is preferable.

 [0030] In the method for producing microcapsules according to the present invention, the method in which the water-soluble polymer compound is allowed to coexist is optional. The water-soluble polymer compound or an aqueous solution thereof is generally added to the system. It is. The addition timing of the water-soluble polymer compound is not particularly limited. That is, it can be added in advance to an aqueous solution containing a water-soluble protein before the core substance is dispersed, or can be added at any time before and after the addition of polyion. Furthermore, even if the water-soluble high molecular weight compound is added to the microcapsule dispersion having a swollen film after the addition of the curing agent, the film has a shrinking effect. However, from the viewpoint of increasing the viscosity of the aqueous solution by adding a water-soluble polymer compound, increasing the viscosity of the dispersion due to film swelling, and changing the coacervate conditions, the water-soluble polymer compound is used after the formation of the coacervate film. It is preferable to add at the time of. In particular, when adjusting the pH after gelling the coacervate film, it is preferable to add a water-soluble polymer compound before that. If the increase in viscosity due to gel swelling exceeds the desired range, it is necessary to apply a greater shearing force to maintain the stirring conditions. If the shearing force is too strong, the capsule film may be destroyed, which is not preferable. .

 [0031] Although the coacervate film has a strong tendency to swell as the pH increases, the water-soluble polymer compound in the present invention suppresses or reduces the swelling of the film, so that the curing conditions are adjusted. When adjusting the pH, it is particularly preferable to add a water-soluble polymer compound before the adjustment. Therefore, it is most preferable to add a pH adjuster and Z or a curing agent to cure the coating after the formation of coacervate coating and gelation in the system after adding poly-on. Before. By adding the water-soluble polymer compound at such time, the water-soluble polymer compound does not affect the formation of the coacervate film, and the surface of the coacervate film is effectively treated with the polymer compound. .

[0032] Further, when transdaltaminase is used as a curing agent, it is necessary to adjust the pH to 5 to 9, preferably 6 to 8 as the curing conditions as described above. Water-soluble polymer compound Coexistence of this suppresses or reduces the swelling of the film. [0033] Note that if the water-soluble polymer compound is not added or the pH is adjusted to a neutral range with insufficient addition, the film tends to swell, but even after the film swells. The addition of a water-soluble polymer compound reduces the swelling of the film. In order to apply the production method of the present invention to an existing production process, it is easy and preferable to adopt such an addition time.

 [0034] The water-soluble polymer compound used in the first method for producing a microcapsule according to the present invention has an electric conductivity of 0.005 to 1.2 SZm, preferably 0.0. 005-0.3SZm.

 [0035] Examples of the water-soluble polymer compound used in the method for producing the second microcapsule according to the present invention include polybulal alcohol, polybulurpyrrolidone, polyethylene oxide, and a mixture thereof. These all suppress or reduce the swelling of the film as described above, and in the present invention, the terms polybulal alcohol, polyvinylpyrrolidone and polyethylene oxide include derivatives thereof. .

 [0036] The water-soluble polymer compound may be a compound in which part or all of the water-soluble polymer compound is modified. In particular, when it is appropriately denatured by a chemical species containing an ionic group, the water-soluble polymer compound itself can be configured to have an appropriate ionicity, interacting with the protein film, and more effective. It is preferable because it acts on (details below).

 [0037] Examples of such an ionic group include a sulfone group, a carboxyl group, and a phosphoric acid group. In the method for producing a microcapsule according to the present invention, one or two or more selected from sulfonic acid and / or carboxylic acid-modified polybulal alcohol is particularly preferable as the water-soluble polymer compound.

 [0038] Also, a copolymer containing the above water-soluble high molecular compound as a polymerization unit, such as a copolymer having polyvinylpyrrolidone as a polymerization unit, can be used. Polyvinyl pyrrolidone and derivatives thereof may act more favorably than other water-soluble polymers when using alkali-processed gelatin as a protein, and are more preferable in combination.

[0039] The molecular weight of these water-soluble polymer compounds is not particularly limited. Molecular weight 2000-200000, preferred <ί or 2000-20000, for later power! Be beaten. In general, water-soluble polymer compounds having a large molecular weight increase in viscosity when used in aqueous solutions, so care must be taken because the microcapsules are excessively sheared due to the load on the stirring power and stirring during microcapsule preparation. Polyvinyl alcohol is not particularly limited to a completely saponified type or a partially saponified type, but a partially saponified type is preferred from the viewpoint of solubility in water.

In [0040] Microcapsules of the production process of the present invention, with the use of such a relatively low electrical conductivity water-soluble polymer compound, after Gerui spoon the core cell base over preparative film, the Eta _[rho For example Even in the neutral region, the film swells. Such swelling of the skin film can be evaluated by the degree of swelling. In the present invention, the degree of swelling is calculated using the following method.

 1) A constant weight is taken from the microcapsule dispersion (ρΗ = 4.3) after the agitation of gel 匕, and the prescribed centrifuge tube (inner diameter 14 mm, height 105 mm: with IWAKI GLASS rim · 16.5 X Using a centrifuge (Centrifuge H-18, manufactured by Kokusan Co., Ltd.), centrifuge at 2000 rpm and lmin to separate into a microcapsule layer and an aqueous solution layer.

 2) Measure the length of the separated microcapsule layer, and calculate the volume of the microcapsule layer from the product of the calculated inner diameter force of the centrifuge tube.

 3) Collected microcapsule dispersion weight and compounding specific force Calculate the volume of the core substance in the dispersion, and calculate the volume of the microcapsule film before pH adjustment based on the volume difference of the microcapsule layer.

 4) Collect a sample from the microcapsule dispersion after completion of addition of water-soluble polymer compound, pH adjustment, addition of curing agent, and curing, depending on the desired timing of addition, and adjust the pH after adjusting the pH using the same method. The volume of the capsule film is calculated.

 5) Based on the film volume before pH change, calculate the amount of increase in film volume after pH adjustment according to the following formula, and use the degree of swelling as a percentage.

The degree of swelling (%) = _{(P H film volume before coating volume _P H adjustment after adjustment) ZPH before adjustment of the film body volume) X 100

[0041] When the water-soluble polymer compound specified in the present invention is used, the method described above is used. The degree of swelling measured is generally from 0% to 60%, preferably from 0% to 20%, more preferably from 0% to 10%.

 [0042] The protein film swells in the neutral region because the increase in pH promotes the dissociation of the carboxyl group of the protein that constitutes the skin film. This is thought to be due to the fact that the amount of -ON increases and the carboxyl groups having the same charge are electrically repelled. The complex 'core cell basis method is driven by the electrical ion complex of polycation and polyanion. Protein temperature does not lead to protein dissolution because the temperature in the system is below the gel point of the protein film. However, protein molecules that are charged with a ionic character cause a phenomenon such as swelling or swelling of the protein film due to electrical repulsion. Is considered to occur. The reason why the swelling of the protein film is suppressed by the coexistence of a specific water-soluble polymer compound in the method for producing the microcapsules according to the present invention is not clear, but the swelling by the electric repulsive force is not clear. It is presumed that the swelling is suppressed or reduced by the molecular coordination of the water-soluble polymer compound to the protein film to be attempted. At this time, if a water-soluble polymer compound having a high electrical conductivity is used, the ion balance is destroyed due to the strong ionicity of the coordinated water-soluble polymer compound. Will be. This is considered to be due to the influence of the density of the ionizable group in the molecular structure of the water-soluble polymer compound to be coordinated. On the other hand, low electrical conductivity, water-soluble polymer compounds, especially relatively low electrical conductivity having moderately ionic groups! It is presumed that swelling is suppressed because the functional polymer compound coordinates effectively and does not destroy the ion balance.

[0043] Micro Capsenore

A first microcapsule according to the present invention comprises a protein as a film and a water-soluble polymer having an electric conductivity of 0.005 to 1.2 SZm when a 10 wt% aqueous solution is used. Further, the second microcapsule according to the present invention has a water-soluble polymer whose film is selected from the group consisting of proteins, polyalbucohol, polybulupyrrolidone, polyethylene oxide, derivatives thereof, and mixtures thereof. Compound and It contains. These microcapsules contain a specific water-soluble polymer compound in the film, so that the swelling of the film is suppressed or reduced, and the distortion of the shape due to pH change is small.

[0044] The microcapsules according to the present invention can be used in various applications by selecting a core material and a coating material. Specific examples include adhesives, adhesives, coloring materials, foods, pharmaceutical products, quasi drugs, fragrances, and cleaning agents. In these applications, since it is necessary to consider toxicity, it is preferable not to use toxic aldehydes such as formaldehyde and dartal aldehyde as the microcapsule material. In addition, volatilization of formaldehyde, which is a VOC, and accidents caused by incorrect usage are also assumed for display media, toys, stationery, etc., which is not preferable. That is, it is preferable that the film does not substantially contain aldehydes having high toxicity that can cause VOCs and sick house syndrome, which are substances subject to emission control. Furthermore, a display medium or a recording material can be formed using the micro force capsule according to the present invention. For example, by using an oily substance containing fine magnetic particles as a dispersion as a core substance, it can be used as an element of a magnetic display medium. Further, if a thermosensitive color-changing substance that changes color by heating is used as a core material, an element of a thermosensitive recording material can be obtained. In particular, as a heat-sensitive discoloration substance, a reversible feeling can be obtained by using a substance capable of color development, decoloration, and decoloration by heat, for example, a combination of an electron-accepting compound and an electron-donating color-forming compound. This can be done by forming a thermal recording material.

[0045] A heat-sensitive recording material using a microcapsule is already known! / For example (Patent Document 7). However, in the manufacturing method of the microcapsules used therefor, aldehydes are often used to harden the protein film! Toxic and environmental considerations The use of such aldehydes is preferable, but as a hardener that can be used in place of aldehydes, for example, only transdaltaminase described above can be used to form a coacervate film. Distortion and film volume expansion occur. For this reason, the final microcapsule has a larger volume of coating than the core material. In order to use microcapsules as a display medium or a recording material, the force to arrange microcapsules on a support is usually the force between microcapsules, even if they are arranged at a high density when the film of microcapsules is expanded. A gap corresponding to the thickness of the swollen film is likely to occur, which causes a decrease in resolution and contrast. However, since the microcapsules according to the present invention have a small volume of the coating compared to the volume of the core material, it is possible to arrange the core material at a high density on the support, so that the resolution and contrast are excellent. In addition, a magnetic display medium substantially free from harmful aldehydes can be provided.

 [0046] The microcapsules according to the present invention that can be used for such applications can be produced, for example, by the above-described method for producing microcapsules. The force for selecting an appropriate size according to the use of the microcapsule is generally selected such that the diameter in terms of a sphere is 0.1 to 3000 / zm, preferably 0.1 to 2000 / ζ πι. Among these, 50 to 1000 m is preferable as a magnetic display medium, and 0.1 to LO / z m is preferable as a heat-sensitive recording material. An appropriate thickness is selected depending on the application.

 [0047] The present invention will be described below with reference to various examples.

 [0048] Example 1

While maintaining the system temperature at 40 ° C and stirring 90 parts by weight of 10% by weight acid-treated gelatin aqueous solution (A P200 manufactured by Futsubi Co., Ltd.), 120 parts by weight of 40 ° C hot water (ion-exchanged water), 120 parts by weight of raffin (Eisoso M, manufactured by Etsuso Chemical Co., Ltd.) was sequentially added and emulsified and dispersed to form OZW emulsion. Further, 90 parts by weight of 1.25 wt% aqueous solution of sodium carboxymethylcellulose (Serogen F-7A manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a polyone was mixed to be uniform. Acetic acid (a reagent manufactured by Wako Pure Chemical Industries, Ltd.) was added to adjust the pH to 4.3 to form a coacervate film. The emulsion was gradually cooled to 5 ° C while stirring to gel the film and kept stable for 30 min at 5 ° C. The temperature of the system was again raised to 15 ° C., and 30 parts by weight of a 10% by weight aqueous solution of sulfonic acid-modified polybulal alcohol (Nippon Gosei Chemical Co., Ltd. Gocelan L3266) was added. A 50 wt% aqueous sodium hydroxide solution was added to adjust the pH to 7.2, and 0.18 part by weight of transglutaminase (Actino TG-S manufactured by Ajinomoto Co., Inc.) was added. Stirring was continued for 16 hours while maintaining the temperature of the system at 15 ° C. to obtain a microcapsule dispersion in which the film was cured. The microcapsules obtained were mononuclear microcapsules with heat resistance and no swelling of the film. [0049] The final concentrations of acid-treated gelatin, sodium carboxymethylcellulose, and sulfonic acid-modified polybutyl alcohol in the aqueous solution of the system were 2.7 wt%, 0.34 wt%, and 0.91 wt%, respectively. .

 [0050] Comparative Example 1

 In the above Example 1, a micro-mouth capsule was produced in the same manner except that the water-soluble polymer compound was not added.

 [0051] Examples 2 to 9, Comparative Examples 2 to 4

 Further, microcapsules were produced in the same manner as in Example 1 except that the water-soluble polymer compound and the pH adjustment value were changed to those shown in Table 1.

[0052] The water-soluble polymer compound, final concentration, electrical conductivity, swelling degree, pH adjustment value, and film thickness at completion ( _PH 6-8) in each example were as shown in Table 1.

[0053] [Table 1]

:so,

Electrical conductivity is measured using ion exchange water with a conductivity of 0.00004 SZm and a 10% aqueous solution of water-soluble polymer compound (electric conductivity meter CM—30V measurement, manufactured by Toa D-keichi Co., Ltd.) Temperature 25 ° C). [0054] The degree of swelling was calculated using the following method.

 1) Collect a constant weight from the agitated microcapsule dispersion (pH = 4.3) after stirring, and use a prescribed centrifuge tube (inner diameter 14 mm, height 105 mm: with IWAKI GLASS rim · 16.5 X Using a centrifuge (Centrifuge H-18, manufactured by Kokusan Co., Ltd.), centrifuge at 2000 rpm and lmin to separate into a microcapsule layer and an aqueous solution layer. The temperature conditions were determined appropriately according to the type of curing agent used, and the temperature conditions immediately before charging the curing agent were used. (15 ° C when transdaltaminase is used as the curing agent, 5 ° C when formaldehyde is used.)

 2) Measure the length of the separated microcapsule layer, and calculate the volume of the microcapsule layer from the product of the calculated inner diameter force of the centrifuge tube.

 3) Collected microcapsule dispersion weight and compounding specific force Calculate the volume of the core substance in the dispersion, and calculate the volume of the microcapsule film before pH adjustment based on the volume difference of the microcapsule layer.

 4) Collect a sample from the microcapsule dispersion after completion of addition of water-soluble polymer compound, pH adjustment, addition of curing agent, and curing, depending on the desired timing of addition, and adjust the pH after adjusting the pH using the same method. The volume of the capsule film is calculated. The temperature conditions were 15 ° C when transdaltaminase was used as the curing agent and 20 ° C when formaldehyde was used.

 5) Based on the film volume before pH change, calculate the amount of increase in film volume after pH adjustment according to the following formula, and use the degree of swelling as a percentage.

The degree of swelling (%) = _{(P H film volume before coating volume _P H adjustment after adjustment) ZPH before adjustment of the film body volume) X 100

 [0055] The film thickness is a value obtained by actually measuring a microcapsule having a core material particle size of about 500 μm with a microscope.

 [0056] The pH measurement was performed using a glass electrode-type hydrogen ion concentration meter (H

M-30S).

[0057] The water-soluble polymer compound used in each example is as follows.

Sulfonic acid-modified polyvinyl alcohol: Goseilan manufactured by Nippon Synthetic Chemical Industry Co., Ltd. L- 3266

Carboxylic acid-modified polyvinyl alcohol: Gosena Ichinole T-330, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

Polybulu alcohol (saponification degree 86. 5-89. 5%): GOHSENOL GL—05, Nippon Synthetic Chemical Industry Co., Ltd.

Polybylpyrrolidone: ISPI 'Japan Co., Ltd. PVP K-15

Butyl acetate Z-Buylpyrrolidone copolymer: Made by ISPI Japan Ltd. PVP / VA S -630

Polyethylene oxide: Meisei Chemical Co., Ltd. Alcox R- 150 Gum arabic: Wako Pure Chemical Industries, Ltd. Reagents

Sodium carboxymethylcellulose: Serogen F-7A from Daiichi Kogyo Seiyaku Co., Ltd.

Sodium polystyrene sulfonate: Reagent manufactured by Wako Pure Chemical Industries, Ltd.

Isobutylene Z maleic anhydride copolymer: Kuraray Co., Ltd. Isoban 104 Sulphonic acid-modified isoprene polymer: JSR Co., Ltd. Dynaflow DK106 Example 10

Maintaining the system temperature at 40 ° C, stirring 10 parts by weight of 10% by weight alkali-treated gelatin aqueous solution (Nitsubi ST1) 120 parts by weight of 40 ° C warm water (ion-exchanged water) and isoparaffin 120 parts by weight were added in order and emulsified and dispersed to form OZW emulsion. Furthermore, 90 parts by weight of a 1.25 wt% aqueous solution of sodium carboxymethylcellulose (Serogen F-7A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a polyone was mixed and made uniform. Acetic acid (a reagent manufactured by Wako Pure Chemical Industries, Ltd.) was added to adjust the pH to 4.0, thereby forming a coacervate film. The emulsion was gradually cooled to 5 ° C with stirring to gel the film and kept stable at 30 ° C for 5 minutes. The temperature of the system was again raised to 15 ° C., and 30 parts by weight of a 10% by weight aqueous solution of polybulurpyrrolidone (PVP K 15 manufactured by ISPI Japan Co., Ltd.) was added. A 50 wt% aqueous sodium hydroxide solution was added to adjust the pH to 7.3, and 0.18 part by weight of transdaltaminase (Ajinomoto Co., Ltd. Activa TG-S) was added. Keep the system temperature at 15 ° C. Further, stirring was continued for 16 hours to obtain a microcapsule dispersion having a cured film. The obtained microcapsules were mononuclear microcapsules having heat resistance with little swelling of the film.

[0059] system alkali-treated gelatin in the aqueous solution of sodium carboxymethyl cellulose, and final concentrations are poly Bulle pyrrolidone 2.73 wt _^0/0, 0.34 weight _^0/0, were you and 0.91 wt% .

 The results obtained are as shown in Table 2.

 [0060] Example 11

 While maintaining the system temperature at 40 ° C and stirring 90 parts by weight of 10% by weight acid-treated gelatin aqueous solution (A P200 manufactured by Futsubi Co., Ltd.), 120 parts by weight of 40 ° C hot water (ion-exchanged water), 120 parts by weight of raffin (Eisoso M, manufactured by Etsuso Chemical Co., Ltd.) was sequentially added and emulsified and dispersed to form OZW emulsion. Further, 90 parts by weight of 1.25 wt% aqueous solution of sodium carboxymethylcellulose (Serogen F-7A manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a polyone was mixed to be uniform. Acetic acid (a reagent manufactured by Wako Pure Chemical Industries, Ltd.) was added to adjust the pH to 4.3 to form a coacervate film. The emulsion was gradually cooled to 5 ° C while stirring to gel the film and kept stable for 30 min at 5 ° C. While maintaining the temperature of the system at 5 ° C., 12 parts by weight of sulfonic acid-modified polyvinyl alcohol (Nippon Synthetic Chemical Co., Ltd. Gocelan L3266) was added and completely dissolved. After adding 3 parts by weight of 37% by weight formaldehyde solution (reagent manufactured by Wako Pure Chemical Industries, Ltd.) and stirring for 30 minutes, 50% by weight aqueous sodium hydroxide and sodium hydroxide solution was added to adjust the pH to 10.0. The temperature of the system was gradually raised to 50 ° C., held for 30 minutes, and then cooled to 20 ° C. with stirring to obtain a microcapsule dispersion in which the film was cured. The obtained microcapsules were mononuclear microcapsules having little heat-swelling and heat resistance.

 [0061] The final concentrations of acid-treated gelatin, sodium carboxymethylcellulose, and sulfonic acid-modified polybutyl alcohol in the aqueous solution of the system were 2.86 wt%, 0.36 wt%, and 3.8 wt%, respectively. .

 The results obtained are as shown in Table 2.

[0062] Comparative Examples 5-6 Microcapsules were produced in the same manner as in Examples 10 and 11 except that the water-soluble polymer compound was not added and the pH adjustment value was as shown in Table 2.

 The results obtained are as shown in Table 2.

[0063] [Table 2]

132 parts by weight of a plastic dispersion in which an oil-based plastic liquid composed mainly of fine magnetic particles and isoparaffin (Esoso M, manufactured by Ethso Chemical Co., Ltd.) is used as a core material, and the system temperature is kept at 40 ° C. However, the SZOZW emulsion was emulsified and dispersed in an aqueous solution that was uniformly mixed with 90 parts by weight of an acid-treated gelatin aqueous solution (AP200 manufactured by Futsubi Co., Ltd.) and 120 parts by weight of 40 ° C hot water (ion-exchanged water). Formed. Furthermore, 90 parts by weight of a 1.25% by weight sodium carboxymethylcellulose aqueous solution (Serogen F-7A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was mixed and made uniform as a polyone. Acetic acid (a reagent manufactured by Wako Pure Chemical Industries, Ltd.) was added to adjust the pH to 4.3 to form a coacervate film. The emulsion was gradually cooled to 5 ° C with stirring to gel the film, and kept stable for 30 min at 5 ° C. The temperature of the system was again raised to 15 ° C., and 30 parts by weight of a 10% by weight aqueous solution of sulfonic acid-modified polybulal alcohol (Goseiran L3266, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was added. A 50 wt% aqueous sodium hydroxide solution was added to adjust the pH to 6.8, and 0.18 parts by weight of transglutaminase (Actino TG-S manufactured by Ajinomoto Co., Inc.) was added. Stirring was continued for 16 hours while maintaining the temperature of the system at 15 ° C to obtain a microcapsule dispersion liquid with a cured film.

 The obtained microcapsule dispersion was coated with a 125 μm thick PET film as a support to form a magnetic display medium. The obtained magnetic display medium had sufficient resolution.

Claims

The scope of the claims  [1] When manufacturing a microcapsule with a protein film using the complex 'coacervation method', a water-soluble polymer having an electrical conductivity of 0.005 to 1.2S Zm when made into a 10% by weight aqueous solution. A method for producing a microcapsule characterized by coexisting a compound.  [2] When producing a microcapsule having a protein film using the complex 'coacervation method', a highly water-soluble polymer selected from the group consisting of polybulal alcohol, polybutylpyrrolidone, polyethylene oxide, and mixtures thereof. A method for producing a microcapsule, comprising coexisting a molecular compound. [3] The method for producing a mic mouth capsule according to claim 1 or 2, wherein the water-soluble polymer compound is 1 or 2 or more selected from the sulfonic acid and Z or carboxylic acid-modified polyhydric alcohol power. . [4] The protein membrane curing agent according to any one of claims 1 to 3, wherein the protein film curing agent is transdaltaminase. A method for producing a microcapsule according to item 1. [5] The electrical conductivity when the film is 10% by weight aqueous solution with protein is 0.005-1.2S. A microcapsule comprising a water-soluble polymer compound which is Zm. [6] The film is characterized by comprising a protein, and a water-soluble polymer compound selected from the group consisting of polybulal alcohol, polybulurpyrrolidone, polyethylene oxide, and derivatives thereof, and mixtures thereof. A microcapsule. [7] The microcapsule according to [5] or [6], wherein the water-soluble polymer compound is a sulfonic acid-modified polyvinyl alcohol or a carboxylic acid-modified polybutyl alcohol. [8] The film according to any one of claims 5 to 7, wherein the film is cured by transdaltaminase. The microcapsule according to item 1. [9] The microcaps nore according to any one of claims 5 to 8, wherein the film contains substantially no aldehydes.  [10] A magnetic display medium comprising the microcapsule according to any one of [5] to [9].