JPS5829238B2 - Microcapsule Tofusoseibutsu - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microcapsule coating composition, and particularly to its extender component.

Coacervation methods, interfacial polymerization, phase separation methods, and the like are well known as methods for producing microcapsules.

The coacervation method involves emulsifying and dispersing hydrophobic substances, such as fragrances and dyes dissolved in oil, in an aqueous solution of a protective colloid rich in protective colloidal properties, such as gelatin (emulsification process).
Next, an aqueous solution of a protective colloid precipitating agent such as gum arabic is added to this, and through various steps, protective colloid is precipitated intensively around the hydrophobic substance (coacervation process).
This process consists of adding a hardening agent such as formalin to harden the protective colloid layer deposited intensively around the hydrophobic substance (hardening step).

In addition, in the interfacial polymerization method, one of the combinations of substances that undergo a polymerization reaction, such as a styrene monomer and a polymerization initiator, or substances that cause a condensation reaction, such as a polyhydric alcohol and a polybasic acid, is added to a hydrophobic substance. The process consists of dissolving the other substance in an aqueous phase, and causing a chemical reaction at the oil-water phase interface to form a synthetic polymer substance barrier.

In any of the above and other microcapsule manufacturing methods, the microcapsules have a form in which a hydrophobic substance is coated with a polymeric substance, and the average particle diameter thereof is 10 microns or less.

When a microcapsule solution containing such microcapsules is applied to a support such as paper without adding any filler, each microcapsule is separated independently from a microscopic point of view. However, since the outer walls of the microcapsules are made of the same material, there is a high affinity and the appearance of the coated layer is similar to that of a single layer provided on a support such as a wax or resin-treated surface. It will look like this, and the feel with your fingers will be far from the feel of white paper.

More importantly, regardless of the manufacturing method, the strength of the capsule wall of the obtained microcapsules is very weak and is easily destroyed by slight friction or pressure.

The extender is also an important component of the microcapsule coating composition as a pressure buffer to prevent such undesirable destruction of the microcapsules.

However, since the microencapsulation liquid has a delicate and complex surface chemical composition, most of the substances commonly used as fillers and extenders for paints etc. can be used for the above purpose and are suitable for use. In view of the above, the present invention aims to provide a microcapsule coating composition characterized by containing an excellent conditioning agent. purpose.

The microcapsule coating composition of the present invention is a microcapsule coating composition containing microcapsules having an average particle size of about 10 microns or less, in which the composition is non-adsorbent, oil resistant, and stable in water dispersibility. Aggregates of particles of a polymer substance are contained as a conditioning agent at a weight ratio of 1/10 to 1 times the weight of the microcapsules, and the average particle diameter of the particles is 1710 to 1 times the average particle diameter of the microcapsule particles.
The average length of the aggregate is 1 to 10 times longer than the average particle diameter of the microcapsule particles.

Further, another composition according to the present invention is a microcapsule coating composition containing microcapsules having an average particle size of about 10 microns or less, wherein the composition removes aggregates of polyvinyl chloride resin particles from the microcapsules. It is contained as a conditioning agent in a weight ratio of 1/10 to 1 times the weight of the capsule, the average particle size of the particles is 1/10 to 1 times the length of the average particle size of the microcapsule particles, and The average length of the microcapsule particles is 1 to 10 times longer than the average particle diameter of the microcapsule particles.

According to the findings of the present inventors, the constitution agent used in the microcapsule coating composition, which is characterized in that the microcapsule contents, such as non-carbon copying paper and fragrance transfer paper, are transferred under pressure to a third party. The conditions that must be met are as follows.

(1) The extender does not adsorb the contents of the microcapsules, does not cause chemical reactions, mutual plasticization, deterioration, or denaturation upon contact with the contents of the microcapsules, and has chemical and physical properties in the composition. Scales that exist in a stable state.

(2) When the microcapsules are destroyed under the conditions of use,
The conditioning agent must not substantially inhibit the destructive process during this use.

(3) In the microcapsule coating composition, the extender should be agglomerated with dispersed microcapsules, and the extender itself should have good dispersibility in the solvent of the composition.

(4) Excellent hiding power and slipping properties, which should be possessed as a conditioner.

That is, if the above condition (1) is not satisfied, before transferring the contents of the microcapsules that flow out due to the destruction of the microcapsules during use to a third party (transfer target),
The extender absorbs and adsorbs this content, resulting in a significant decrease in the transfer rate.0 Oil absorbency of fillers and extenders commonly used in other fields, such as calcium carbonate, barium sulfate, silica, and talc. Materials that undergo plastic modification upon contact with substances or oily substances such as polystyrene resin powders are also not suitable for the purpose of the present invention because they do not satisfy the above condition (1).

If the above condition 2) is not satisfied, when the microcapsules are broken under pressure during use, the conditioning agent will absorb the applied pressure and the required breakage of the microcapsules will not occur.

For example, a balloon-like micro organic hollow sphere falls under the above-mentioned unsuitable example.

Condition (3) stipulates that the extender itself should have good dispersibility in water, which is the solvent of the microcapsule coating composition, that is, it should have excellent slurry properties. Examples include various metal powders and hollow microspheres that tend to settle or float inside.

The above condition (4) is a condition for preventing the coating layer from forming a single layer after coating and drying the microcapsule coating composition on the support, and for improving the quality of the appearance, and the lubricity is insufficient. If this is the case, a coated surface that feels rough and has a foreign substance feel will be formed.

Glass powder, acicular cellulose flocs, etc. are unsuitable examples under these conditions.

In addition to the above conditions, in order to sufficiently protect the weak outer wall of the capsule from undesirable destruction during unavoidable pressurization in emergencies, the conditioning agent must have appropriate pressure buffering properties. The importance is as mentioned above.

The composition of the composition of the present invention will be explained in detail below.

The microencapsulated liquid in the composition of the present invention can be obtained by the well-known methods described above, and the average particle size of the microcapsules is usually 10 microns or less.

Preferred examples of the polymeric substance which can constitute the extender of the composition of the present invention include polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinylidene chloride resin, acrylic resin, These include cellulose acetate resin, vinyl chloride-acrylic resin, and the like.

The extender of the composition of the present invention is produced by agglomerating the resin powder particles as described above by a well-known method.

The average particle size of the resin powder particles suitable as the extender component of the microcapsule coating composition is 1/10 to 1 times the average particle size of the microcapsules, and the average length of the aggregates of the powder particles is 1/10 to 1 times the average particle size of the microcapsules. 1 to 10 of the average particle diameter of
It was found that the amount of aggregates in the composition should be between 1/10 and 1 times the weight of the microcapsules [7].

The aggregate of polyvinyl chloride resin powder particles, which has been found to be the most suitable as the extender of the present invention in terms of oil resistance, water dispersibility, and price, will be described in detail below.

The polyvinyl chloride resin aggregate is a so-called polychlorinated resin extracted from a highly polymerized polyvinyl chloride resin emulsion obtained by an emulsion polymerization method or a suspension polymerization method at a temperature below the glass transition point (Tg point) of the polyvinyl chloride resin. Commercially available resin powder as powder for vinyl paste or so-called powder molding polyamide obtained by crushing and pulverizing the resin pellets by a wet crushing method such as a thin crushing method or a dry crushing method such as an air jet crushing method. It is produced by subjecting vinyl chloride resin powder to a well-known agglomeration treatment before and after the Tg point, if necessary.

When the polyvinyl chloride resin aggregate thus obtained is added and used as an extender in the composition of the present invention, its adsorption ability to the contents of microcapsules is completely different from that of various inorganic extenders due to its smoothness. It is highly non-oil-absorbent, and has excellent oil and solvent resistance due to its high degree of polymerization, and exhibits stability without causing plasticization, deterioration modification, or any other chemical reactions in the composition. It fulfilled the following.

Furthermore, when microcapsules are broken under pressure under reliable conditions, the aggregates in the composition completely return to primary particles and slide back under the pressure, thus causing no adverse effect on use. , the above condition ■ is satisfied, and the above condition ■
Regarding the above condition (2), since the specific gravity of the aggregate is 14 to 1.7, it does not settle or float in the composition and exhibits good water dispersibility. Because the powder was approximately spherical in shape, the coated surface felt good after coating and drying on the support, with no foreign body sensation. The present invention provides an extremely excellent composition for coating microcapsules that has a wide range of uses for the purpose of transferring microcapsules, and is of great benefit to the industry.

As mentioned above, many methods have been proposed for microencapsulation of hydrophobic substances. Here, the present invention will be explained in more detail based on the following non-limiting examples, using the conventional coacervation method as an example. explain.

Note that the numbers in the examples indicate parts by weight.

Example 1 A hydrophobic substance was prepared by dissolving 0.8 parts of crystal violet lactone and 0.4 parts of benzoyl leucomethylene blue in 2.5 parts of isopropylnaphthalene, and on the other hand, 6.5 parts of acid-treated gelatin was dissolved in warm pure water at 60°C. Dissolved in 50 parts,
A protective colloid liquid was prepared by adjusting the pH to 9.5 with a 10% NaOH aqueous solution, and then the two were mixed and emulsified in a homomixer. 5 parts of gum arabic and 0.5 parts of a 20% sodium polyacrylate aqueous solution were added to 60 parts of a 20% sodium polyacrylate aqueous solution. A solution obtained by dissolving the solution in 50 parts of warm pure water at 10°C and adjusting the pH to 9.5 with a 101 NaOH aqueous solution is further added and high-speed emulsification is carried out for 30 minutes (emulsification step).

Next, 200 parts of warm pure water at 60°C was added dropwise to the obtained solution over 30 minutes, and then the pH of the system was lowered to 4.2 with a 10% glacial acetic acid aqueous solution over 30 minutes ( coacervation process).

Next, the entire system was cooled in a 7-part trench, 7 parts of formalin was added, and the pH of the system was raised to 101 with a 10% NaOH aqueous solution to harden the gelatin (hardening process), and the average particle size of the microcapsules was A dye type non-carbon copying paper microcapsule liquid having a size of 5 microns was obtained.

The tree climbing is adjusted by repeating washing and centrifugation of this solution.
A microcapsule solution containing 10 microcapsules by weight was obtained.

100 parts of this microcapsule liquid was separated, and 8 parts of resin aggregates for polyvinyl chloride paste (average degree of polymerization 1600, average particle diameter 0.5μ, average major axis of aggregates 10μ) were added as a extender, and a fixing agent. 2 parts of carboxymethylcellulose soda was added to prepare a microcapsule coating agent.

This paint is made of acid clay at a dry solid content of 12g/m.
It was coated and dried on paper to give a dry solid content of 7 g/m on the back side of the acid clay surface of paper commercially available as the bottom paper of so-called dye-type non-carbon copying paper. An inner sheet of dye-type non-carbon copying paper was obtained.

When ten sheets of this paper were stacked and placed between the platens of a typewriter and printed, very clear copies could be made of all the sheets and no platen marks were observed.

Furthermore, both the feel and appearance of the surface coated with the microcapsules were completely indistinguishable from those of the paper support.

Therefore, the presence or absence of exposure of the support was undetectable.

For comparison, 2 parts of cellulose floc pulverized to a length of 10 microns as a lengthening agent and 2 parts of carboxymethyl cellulose soda as a fixing agent were added to 100 parts of the microencapsulation liquid to obtain a typewriter paper. A printing test was conducted using

As a result, although the amount of extender was small enough to cause platen marks, a rough foreign body feeling was observed in terms of appearance and feel, probably due to the needle-like crystals.

Example 2 A microencapsulated liquid having an average particle size of 10 microns was obtained in the same manner as in Example 1 using 25 parts of rose oil as a hydrophobic substance.

The microcapsule content was adjusted to 10 g/w in the same manner as in Example 1.

To 100 parts of this liquid, polyvinyl chloride resin pellets with an average degree of polymerization of 500 were wet-milled with water and a colloid mill, and T
2 parts of polyvinyl chloride resin aggregates (average particle size 10μ, long diameter of aggregates 50μ) taken out at g-point temperature and 2 parts of carboxymethyl cellulose as a binder were added,
A microcapsule coating agent for fragrance transfer paper was obtained.

When this coating was applied to paper to a dry solid content of 29/rrl and dried, a fragrance transfer paper was obtained in which the coated surface was indistinguishable from the paper itself in terms of appearance and feel.

When a rose flower pattern was artistically printed on the capsule-coated surface, the finish was no different from that of regular paper.

When I layered this on a handkerchief and applied pressure with a fountain pen cap, I was able to transfer the rose scent to the handkerchief.

For comparison, an attempt was made to add glass microballoons (glass microscopic hollow spheres: specific gravity 0.5) as a conditioning agent to the microencapsulated liquid, but due to the difference in specific gravity, it was difficult to obtain a uniform coating material. could not.

Some examples of embodiments of the present invention are summarized below. (1) Hydrophobic substances are microencapsulated into particles with an average particle diameter of 10 microns or less by various methods such as coacervation, interfacial polymerization, and phase separation. After applying and drying the microcapsule coating agent on the support, the microcapsule contents are adsorbed as a conditioner added in the microcapsule coating composition for the purpose of transferring the microcapsule contents to a third party by pressure. It is not denatured by chemical reaction or plasticization deterioration due to continuous contact, and has an average particle size of a single O particle between the top and one times the average particle size of the microcapsules, and furthermore, it has an average particle size of 1 times the average particle size of the microcapsules. A microcapsule application composition consisting of adding polymer compound aggregates whose long diameter is at least twice as long and not more than 10 times the weight of microcapsules at a weight ratio of not less than 1 times but not more than 1 times the weight of the microcapsules of an adult cow. thing.

(2) Microcapsule hydrophobic substances into particles with an average particle diameter of 10 microns or less using various methods such as coacervation, interfacial polymerization, and phase separation, apply microcapsule coating to a support, dry it, and then apply pressure to microcapsule it. Microcapsules that do not adsorb the contents of the microcapsules and are not subject to chemical reactions, plasticization, deterioration, or denaturation upon contact as a conditioning agent added in microcapsule coating compositions intended to transfer the contents of the capsules to a third party. The average particle diameter of a single particle is between ± and 1 times the average particle diameter of A microcapsule coating composition comprising adding a vinyl chloride resin aggregate at a weight ratio of ±2 times or more and 1 time or less the weight of microcapsules in a microcapsule liquid.

Claims (1)

[Scope of Claims] 1. A microcapsule coating composition containing microcapsules having an average particle size of about 10 microns or less, wherein the composition is a stable polymeric substance that is non-adsorbent, oil-resistant, and water-dispersible. Contains aggregates of particles as a conditioning agent at a weight ratio of 1/10 to 1 times the weight of the microcapsules, and the average particle diameter of the particles is 1/10 to 1 times the average particle diameter of the microcapsule particles. The composition is characterized in that the average major axis of the aggregate is 1 to 10 times longer than the average particle diameter of the microcapsule particles. 2. In a microcapsule coating composition containing microcapsules with an average particle diameter of about 10 microns or less, the composition may coat aggregates of polyvinyl chloride resin particles in an amount of 1/1° to 1 times the weight of the microcapsules. The average particle diameter of the particles is 1/10 to 1 times longer than the average particle diameter of the microcapsule particles, and the average major axis of the aggregate is equal to or greater than the average particle diameter of the microcapsule particles. The above-mentioned composition is characterized in that the length is 1 to 10 times the diameter.