JPH01262943A - Microcapsule containing diazonium salt - Google Patents

Abstract

PURPOSE:To stably produce a microcapsule incorporating diazonium salt in which a solvent is not substantially contained by dispersing the liquid wherein diazonium salt and high molecular substance are dissolved in a nonaqueous solvent into a hydrophilic colloid soln. and raising the temp. of the soln. CONSTITUTION:In the production of a microcapsule of thermal development type copying material, both diazonium salt and a compd. which produces high molecular substance such as polyurethance by reaction are dissolved in a nonaqueous solvent such as halogenohydroearbon having b.p. of 40-95 deg.C at ordinary pressure and fatty acid ester. When this soln. is dispersed and emulsi fied in a hydrophilic colloid soln., and thereafter this system is raised in temp., wall forming substance is migrated on the surfaces of oil droplets and therein high molecule formation reaction due to polyaddition and polycondensation is advanced and a wall film is formed. By such a way, a microcapsule incorpo rating diazonium salt wherein the solvent is not substantially contained is stably produced.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing microcapsules containing diazonium salts used in novel heat-developable copying materials. More specifically, the present invention relates to a method for producing microcapsules of 0.3 to 12 μm in size, which have a wall made of a polymeric material and do not substantially contain a solvent.

<Prior Art> Many methods are known for producing microcapsules containing hydrophobic liquids.

The enumeration is as follows.

(2) Phase separation method from aqueous solution (U.S. Pat. Nos. 2,900,457 and 2,800,458), which is the most common and practically used method and utilizes coacervation of a hydrophilic colloid sol.

■Interfacial polymerization method (Special Publication No. 38-19574, Special Publication No. 42
-446, Japanese Patent Publication No. 42-771, British Patent No. 989
No. 264, No. 950443, No. 867797,
No. 1069140, No. 1046409), the monomer or initial condensate as the first wall-forming material is incorporated into the oil-based liquid without using a completed polymer as the wall material of the microcapsules. Let it exist,
Dissolving a second wall-forming substance having a group capable of reacting with the first wall-forming substance in a polar solvent that is immiscible with the oily liquid;
The first wall film forming substance and the second wall film forming substance are polymerized at the interface between the oil droplets of the oily liquid and the polar solvent to form a wall film.

■Method by polymerization of monomers in oil droplets
No. 9168), a compound having a double bond such as an acrylic compound, styrene, or vinyl acetate is dissolved in an oil droplet, and a peracid compound is used as a catalyst to proceed with radical polymerization to form an oil-insoluble polymer. Generate.

■ Melting dispersion cooling method (British Patent No. 952807 No. 96)
No. 5074), a stable substance that is solid at room temperature and becomes liquid upon heating is used as the microcapsule wall membrane. Use wax or thermoplastic resin.

■The spray dryer method (US Patent No. 3,111,407, British Patent No. 930,422) applies the principle of spray drying, in which solid particles or liquid are emulsified and dispersed in a polymer solution and are applied to a spray dryer.
The dispersion liquid is ejected from the atomizer in the form of fine particles, and at that moment the contained substance is surrounded by the polymer.

These methods have manufacturing problems such as complicated manufacturing methods and difficulty in controlling the capsule size, as well as the fact that the performance of the capsules is largely controlled by the solvent present as the core material. It also has a period of 3. In particular, in a capsule containing a diazonium salt as in the present invention, even if an attempt is made to bring out the characteristics of the diazonium salt, the characteristics may be hidden by the coexisting solvent.

Therefore, a first object of the present invention is to provide diazonium salt-encapsulating microcapsules that are substantially free of solvent.

A second object of the present invention is to provide a method for stably producing diazonium salt-encapsulating microcapsules that are substantially free of solvent.

<Means for Solving the Problems> The above-mentioned object of the present invention is to provide a non-aqueous solvent having a boiling point of 40°C or more and 95°C or less at normal pressure with a diazonium salt and the same or different species that react with each other to produce a polymeric substance. After dispersing and emulsifying a solution of the compound dissolved in a hydrophilic protective colloid solution, the system is heated to transfer wall-forming substances to the oil droplet surface, and polymer formation occurs through polyaddition and polycondensation on the oil droplet surface. This was achieved by a method for manufacturing microcapsules, which is characterized by allowing a reaction to proceed and forming a wall membrane. At this time, it is preferable to distill off the non-aqueous solvent while reducing the pressure in the reaction vessel during the wall film forming reaction.

In the above production method, the non-aqueous solvent is preferably at least one compound selected from halogenated hydrocarbons, fatty acid esters, ketones, and ethers, and the polymeric substance forming the walls of the microcapsules is polyurethane. , polyurea, etc.

The non-aqueous solvent having a boiling point of 40'C to 95C at normal pressure used in the present invention is preferably used in an amount of 5 to 100 parts by weight per 10 parts by weight of the diazonium salt as the solute.

Specific examples of the nonaqueous solvent used in the present invention are listed below, but the present invention is not limited thereto. (
) indicates the boiling point at normal pressure.

Acetone (56), iso7 methyl methyl ether (91)
, Isobutyl methyl ketone (94), Methyl isobutyrate (92), Ethyl isobutyl ether (79), Ethyl isopropyl ether (54), Ethyl propyl ether (64).

t-7mil chloride (86), ethylene chloride (84), isobutyl chloride (69), butyl chloride (78).

Ethylidene chloride (57), propyl chloride (46), methylene chloride (42), ethyl formate (54).

Propyl formate (81), methyl methyl ether (
59), methyl phosphoroformate (71).

Ethyl acetate (77), methyl acetate (57).

Carbon tetrachloride (77), 1,1-dichloropropane (86
), trichlorethylene (87).

Methyl propionate (80), propyl ether (
91), methylchloroform (74).

Riooform (61) When the preferred polymeric material is polyurea or polyurethane, the same or different compounds that form the walls of the microcapsules used in the present invention and which react with each other to produce a polymeric substance are the corresponding monomers. is selected from the incyanate compounds shown below. The amount of monomer used is such that the average particle size of the microcapsules is 0.3μ to 12μ,
The wall thickness is determined to be 0.01μ to 0.3μ.

Specific examples of monomers used in the present invention are listed below, but the present invention is not limited thereto.

General formula [1] NCONCONC0 (n is an integer of 0 to 10) The aromatic isocyanate used in the present invention is -
Maximum n = 0.1.2°3,...10 indicated by (1)
It may be a single item or a mixture of these.

Specific examples of the aliphatic polyisocyanate used in the present invention include hexamethylene diisocyanate,
Propylene-1,2-diisocyanate, butylene-1
, 2-diisocyanate, ethyridine diisocyanate, Schiff 0 hexylene 1,4-diisocyanate, isophorone diisocyanate, adduct of hexamethylene diisocyanate and trimethylolbutane, adduct of hexamethylene diisocyanate and hexanetriol, hexamethylene diisocyanate There are biuret forms of hexamethylene diisocyanate, incyanurate forms of isophorone diisocyanate, and isocyanurate forms of isophorone diisocyanate.

For the purpose of changing the physical properties of the wall of the microcapsules, diamines and diols may be present in the presence of the above-mentioned isocyanate to carry out the polymerization reaction.

The diazonium salt used in the present invention mainly refers to aromatic diazo compounds, and more specifically refers to aromatic diazonium salts, diazosulfonate compounds, and diazoamino compounds.

A diazo compound is a compound represented by the general formula ArN2X. (In the formula, Ar represents a substituted or unsubstituted aromatic ring%
N represents a diazonium group, and x represents an acid 7 ion. ) Specific examples of the diazo compound used in the present invention include the following examples.

4-Diazo-1-dimethyl 7minobenzene 4-diazo-
2-Butoxy-5-chloro-1-dimethyl 7 Minobenzene 4-Diazo-1-methylbenzylaminobenzene 4-Diazo-1-ethylhytooxyethyl 7 Minobenzene 4-Diazo-1-diethyl 7 Mino 3-methoxybenzene 4-Diazo -1-morpholinobenzene 4-diazo-1-morpholino-2,5-dibutoxybenzene 4-diazo-1-tolylmercapto-2,5-jethoxybenzene 4-diazo-1-piperazino-2-methoxy-5- Chlorbenzene 4-diazo-1-(N,N-dioctylaminocarbonyl)benzene 4-diazo-1-(4-tert-octylphenoxy)benzene 4-diazo-1-(2-ethylhexanoylpiperidino)- 2,5-dibutoxybenzene 4-diazo-1-(2
,5-di-tert-7-milphenoxyα-butanoylpiperidino)benzene4-diazo-1-(4-methoxy)phenylthio-2,
5-jethoxybenzene 4-diazo-1-(4-methoxy)benzamide-2,
5-Jethoxybenzene 4-Diazo-1-pyrrolidino-2-methoxybenzene Specific examples of the acid that forms a diazonium salt with the above diazo compound include the following examples.

Cn F 2M+I COOH (n is an integer from 1 to 9)
CM F2m+I S 03 H (m is an integer of 1 to 9) boron tetrafluoride, tetraphenylboron hexafluorophosphoric acid, aromatic carboxylic acid, aromatic sulfonic acid.

Metal halides (zinc chloride, cadmium chloride, tin chloride)
etc.) When the microcapsules of the present invention are used in a copying material, it is preferable to contain a free radical generator and a vinyl monomer, if necessary, in the microcapsules along with a diazonium salt.

Examples of the hydrophilic protective colloid of the present invention include natural or synthetic hydrophilic polymeric substances such as gelatin, gum 7-Rabi-7, casein, carboxymethyl cellulose, starch, and polyvinyl alcohol. In addition, surfactants may be used for emulsification and dispersion, such as anionic surfactants such as alkylbenzene sulfonate, flukylnaphthalene sulfonate, polyoxyethylene sulfate, There are nonionic ones such as ethylene furkyl ether and sorbitan fatty acid.

The microcapsules of the present invention are characterized in that they do not substantially contain a non-aqueous solvent, and the present inventors removed the non-aqueous solvent contained in the microcapsules by the following method. ``substantially free'' of the present invention was defined.

The microcapsules of the present invention are rarely used as a capsule liquid alone, but are generally used in a manner in which a coating liquid is prepared together with a coupler and a base, coated and dried, and then present in a film of a copying material. Therefore, the amount of non-aqueous solvent contained in the coating film, which was present at several percent in the capsule liquid stage, was below the detection limit.

Microcapsule liquid produced by the production method of the present invention 0.
19 was weighed into a 20 cc volumetric flask, methanol was added to make the volume exactly 20 cc, and the mixture was left for 30 minutes.

2 CC of the above methanol solution was measured using a microsyringe and injected into a gas chromatograph mass spectrometer (Hitachi M-8013). Column is TENAX 3mm
φX1m was used. m/z depending on the solvent to be measured
Quantification was performed using the peak. (For example, in the case of ethyl acetate, m/z = 43; in the case of methylene chloride, the peak of 84 was used.) According to this measurement method, the microcapsule liquid of the present invention contains 0.01 to 3.00% non-containing material. Contains water solvent.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited by these Examples.

<Example 1> 3.45 parts of 1-morpholino-2,5-dibutoxybenzene-4-diazonium hexafluorophosphate, xylylene diisocyanate and trimethylolpropane (3.45 parts)
: 1) 18 parts of the adduct were added to 10 parts of ethyl acetate and dissolved by heating. This diazo compound solution was mixed with an aqueous solution containing 5.2 parts of polyvinyl alcohol dissolved in 58 parts of water, and emulsified and dispersed at 20°C to obtain an emulsion having an average particle size of 2.5 μm. 100 parts of water was added to the resulting emulsion and heated to 60"C without stirring. After 2 hours, a capsule solution containing the diazo compound as the core substance was obtained. During the reaction, the container was heated with a water pump. It was maintained under reduced pressure of iQQmmHg to 130mmH9.

The amount of ethyl acetate in the capsule liquid was determined using the measurement method described above, and a value of 0.87% was obtained.

<Example 2> Next, 10 parts of 2-hydroxy-3-naphthoic acid 7nylide and 10 parts of triphenylguanidine were added to 200 parts of a 5% polyvinyl alcohol aqueous solution and dispersed in a sand mill for about 24 hours to form a dispersion with an average particle size of 3μ. I got something.

To 50 parts of the capsule solution of the diazo compound obtained in Example 1, 50 parts of a dispersion of a coupling component and triphenylguanidine and 10 parts of a 40% calcium carbonate dispersion were added to prepare a coating liquid. Spread this coating solution on smooth high-quality paper (759/
dry weight 109/m using a coating bar on m2)
2 and dried at 50°C for 1 minute to prepare a copying material.

0.05 m2 of this copying material was immersed in 20 cc of methanol for 1 hour, and the resulting extract was measured by the method described above. As a result, the content of ethyl acetate was below the detection limit.

~that's all~

Claims (1)

[Claims] 1) A solution of a diazonium salt and the same or different compounds that react with each other to produce a polymer substance is dissolved in a non-aqueous solvent having a boiling point of 40°C or more and 95°C or less at normal pressure. After dispersion and emulsification in a protective colloid solution, the system is heated to move the wall-forming substance to the oil droplet surface, and a polymer production reaction by polyaddition and polycondensation proceeds on the oil droplet surface to form a wall film. A method for producing microcapsules containing a diazonium salt, the method comprising: 2) In the method for producing microcapsules according to claim 1, substantially solvent-free microcapsules are produced by distilling off the non-aqueous solvent while reducing pressure in the reaction vessel during the wall film forming reaction. How to get it. 3) The nonaqueous solvent in which the diazonium salt is dissolved is at least one compound selected from halogenated hydrocarbons, fatty acid esters, ketones, and ethers. Method for manufacturing microcapsules. 4) The microcapsule according to claim 1, wherein the polymeric substance is formed of at least one selected from polyurethane and polyurea.