JPH02261535A - Coating method - Google Patents

Abstract

PURPOSE: To coat or encapsulate solid particles or the like by unstabilizing the melt of a coating material contg. a dispersion phase of the solid particles and/or liquid droplets to cause the melt to crumble to a particulate material. CONSTITUTION: The melt of the coating material contg. the dispersion phase of the solid particles and/or liquid droplets is formed. This melt is then unstabilized by addition of the solid particles and/or cooling thereof and as a result thereof, the melt is caused to crumble to the particulate material contg. the particles consisting of the particles of the dispersion phase and/or droplets embedded therein. As a result, the solid particles and/or the liquid droplets are coated or encapsulated. Adequate examples of the coating material include an org. polymer, fatty acid or the like and adequate examples of the liquid droplets include a foaming agent, fiber softener or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for agglomeration, coating or encapsulation.

The method of the invention has a wide range of applications. This method can be used to coat or encapsulate solid particles, liquid droplets or mixtures of these two substances.

The invention primarily relates to a method of coating or encapsulating solid particles and/or liquid droplets. The method comprises a first step of forming a melt of coating material containing said particles and/or droplets as a dispersed phase, addition of solid particles and/or
or destabilize the melt by cooling, so that the melt collapses (crumples) and embeds particles and/or droplets of the dispersed phase in the coating material. and a second step of making the particulate material contain. This coating method can be used as a means of aggregating dispersed phase particles.

The invention secondly relates to the granular material obtained by said method.

Applicant's unpublished European patent application EP-^-303416
by using polyalkylene or a copolymer containing at least 70% polyalkylene as the coating material and by using water-insoluble inorganic abrasives both as particles to be coated and as particles to destabilize the melt. One embodiment of the invention is disclosed.

Therefore, water-insoluble solid particles constituting the only dispersed phase,
30% of the polyalkylene or another monomer containing carboxylic acid or ester groups constituting the organic polymeric material.
% or less are not included in certain embodiments of the invention.

The essence of the invention is that a melt containing a sufficient amount of dispersed phase crumples and transforms into a granular material in which the dispersed phase is embedded in particles of the initially continuous phase. It lies in the discovery of gaining. This crumblin
g) occurs when a greater amount of dispersed phase becomes present than can be supported by the continuous phase. This phenomenon can be caused by reducing the dispersed phase supporting capacity of the continuous phase by cooling, or by adding an appropriate amount of material to increase the total amount of dispersed phase material. Solid substances locally cause crumple formation, and cooling has the effect of promoting this phase separation. Therefore, the maximum effect can be obtained by combining cooling and addition of a solid dispersed phase.

The coating material that makes up the melt usually consists of one or more organic compounds. This material may in particular be an organic polymeric substance that melts at temperatures above room temperature. or,
Waxy substances such as paraffin wax may be used as coating materials.

Alternatively, organic compounds containing alkyl groups of detergent chain length, such as those found in surfactants, soaps or fatty acids, ie having from 8 to 20 carbon atoms, can be used as coating materials.

One of the advantages of the present invention is that fine particles and mixtures of particles within a suitable size range can be effectively coated or encapsulated. Some known coating methods cannot be used with fine particles, such as fluidized bed coating.

The present invention can be used to coat or encapsulate any number of substances and therefore can be used for a variety of useful purposes depending on the type of encapsulating substance and polymeric coating material.

One of the features of the present invention is that solvents are not normally used;
The aim is to obtain a completely solvent-free product.

Since the invention can be implemented in a variety of ways, a simple general example will be presented first, followed by a more comprehensive description. This example involves coating sodium chloride with polyethylene glycol having an average molecular weight of 20,000. The composition of the final product in weight percent is as follows:

Polyethylene glycol (PEG20,000): 2
5% Sodium Chloride 65% Average Particle Size 7x 10-Duck Silica: 10% First, the polyethylene glycol is heated to a temperature somewhat above its melting point. Microcrystalline sodium chloride is mixed into the molten polymer to generate a dispersed phase in the melt. This melt is cooled to a temperature slightly higher than the melting point of the polymer. Silica is added and the mixture is further cooled. As a result, the melt becomes granular due to crumple formation. Most of these particles consist of agglomerates of sodium chloride crystals embedded in coagulated polymers, and the silica is primarily on the outside of these particles.

In this example, polyethylene glycol constitutes the organic polymeric coating material, sodium chloride is the solid dispersed phase, and silica functions as the "crumple agent." A crumple agent is a substance that changes a melt into particles such as crumples.

In order for a coating material to effectively coat another substance, it must have adequate compatibility with that substance, otherwise phase separation will occur or it will become weak and flake off. A coating that is easy to coat will be formed.

This compatibility may be improved, if desired, in any of the following ways.

(i) Coating the solid dispersed phase with a coupling agent (known per se) consisting of a silane or a titanate.

(ii) creating a bond between the coating material and the dispersed phase;

(iii) at the interface between the dispersed phase and the coating material;
A surfactant is added to form a bridge.

Surfactants may be incorporated into or used as coating materials. 1 coating
If more than one is used, the surfactant may form a "bridge" to improve compatibility between the coating materials.

In the method of the invention, the dispersed phase does not necessarily have to be solid. Liquid dispersed phases may also be used instead of or in addition to solid dispersed phases. The liquid dispersed phase can be a material that is liquid at room temperature, or a material that is solid at room temperature but has a melting point low enough to be liquid at the processing temperature.

Alternatively, filling the pores of a porous dispersed phase with a liquid;
Alternatively, the liquid may be dispersed in the coating material applied to the solid dispersed phase; in fact, the liquid may be present both in the coating material and in the porous solid dispersed phase.

The method of the invention can be used in many applications. These uses include the following.

When fine particles are agglomerated to a larger, more appropriate size. This is caused by, for example, the dustiness of fine substances.
ess) or help improve low flowability.

A protective coating that protects a substance from the surrounding environment until it is ready for use. This can be used, for example, to protect chemically reactive substances until use.

Where the presence of a coating delays or modulates the release of the substance and causes it to run slowly.

When changing a liquid into a granular solid substance. This is useful, for example, when mixing liquid components with particulate solid materials.

When multiple substances are grouped together. This can be used, for example, to prevent segregation of substances contained in particulate final products.

This basic method can be varied in many ways.

For example, a liquid pre-coating may be applied to a solid dispersed phase. This pre-coating can in particular be a coating of a surfactant or a surfactant-containing liquid. Such a precoating may serve to provide a desired degree of compatibility with the polymeric coating material. The precoating of the solid dispersed phase also acts as a shielding layer to keep the potentially reactive solid dispersed phase isolated during high temperature mixing with the polymer.

If the solid dispersed phase is porous, it may be coated with a precoating of a high molecular weight polymer and then coated with a low molecular weight coating material to prevent excessive absorption of the coating material by the porous solid.

As another variation, multiple coating layers can also be formed in the method of the invention. In that case, in particular, one of the methods of the invention
According to one aspect, the particles may be encapsulated with a first coating material, followed by forming an outer second coating by another method of the present invention or another coating technique, such as fluidized bed coating.

If two coatings are provided, for example, the inner coating may provide mechanical strength and the outer coating may form a shield protecting the article to be coated from the surrounding environment. Alternatively, the outer coating may be formed as a water-insoluble (or less soluble) outer coating covering water-soluble or water-swellable particles.

With this structure, when particles are placed in water,
Release of the encapsulated material is delayed until water penetrates into the outer coating. When water penetrates into the inner substance, the inner substance expands and can destroy the outer coating at that point, so that the outer coating does not interfere with the release of the substance, which is delayed to the extent that the presence of the outer coating provides. .

In accordance with this boating concept, it is also possible for the inner particles (ie the particles to be coated with the outer second coating) to contain a water-swellable crumple agent. Alternatively, the particles may include a water-soluble or water-swellable organic polymeric material as the first coating material. In that case,
The outer second coating retards the release of any portion of the encapsulated dispersed phase until water penetrates the outer coating, after which dissolution or swelling of the organic polymeric material in the particles modulates the rate of release of the dispersed phase. It can be done.

Here, substances (materials) that can be used in the present invention will be explained.

As coating materials, for example, organic polymers or copolymers suitable for the end use of the encapsulated dispersed phase can be used. The polymeric material must be such that it melts at a temperature suitable for incorporating the dispersed phase. Mixtures of polymers may also be used as coating materials.

If it is desired to use a polymer that has a high melting point or that decomposes before reaching its melting point, a low molecular weight polymer can be used as a solvent for the polymer. Alternatively, an organic solvent may be used to form a viscous concentrated solution of the polymer.

The use of high molecular weight polymers may have the advantage of reducing the amount of crumple agent required.

Non-soap surfactants can also be used as coating materials. The surfactant may be derived from polymers such as fatty acyl and fatty diacyl derivatives of polyethylene glycol, or may be otherwise.

Other useful coating materials include mixtures of soaps and fatty acids. Other waxy materials such as paraffin waxes having melting points above room temperature can also be used as copolymer materials.

Blends of materials may be used to obtain the desired properties of the coating material. This blend is especially
It can be a blend of two or more polymers, or a blend of one or more polymers with a non-soap surfactant or a soap and a fatty acid.

For example - surfactants may be used as solvents for high molecular weight polymers.

If the coating material is a blend of mutually compatible materials, the melting and crystallization behavior of the components of the blend will change. These properties of the blend can be measured by differential scanning calorimetry.

Blends of coating materials may be selected such that release of the encapsulated material occurs by any of the following phenomena (conditions).

physical pinnae of the coating; dissolution of the coating upon exposure to water; swelling of the coating upon exposure to water; penetration of water into the insoluble porous coating and the resulting failure due to swelling of the encapsulated material; Exposure to specific temperatures, &exposure to specific pH.

Specific examples of coating materials that can be used alone or as blends are listed below.

1. Polyethylene glycol (PEG) and polyethylene oxide (PEO): This system has an extremely wide range of molecular weights ranging from hundreds to millions. PEG can be used alone as a coating agent or can be used to dissolve other polymers.

2. Polyvinylpyrrolidone (PVP): Usually used in combination with other polymers.

3. Poly(acrylic acid) (FAA): weak acid.

4. Cellulose acetophthalate) (CAP): Weak acid.

5. Polyvinyl acetophthalate (PI/AP): Weak acid.

Materials 3.4 and 5 are useful in systems where the release of the coated material is pH dependent.

6. Poly(caprolactone) (PCL); Poly(caprolactone) diol (PCL-diol).

Although PCL is not water-soluble, it is highly permeable. It may also be used to form blends with other water-soluble polymers.

7. Poly(ethylene-vinyl acetate) copolymer (EVΔ
CCP).

8. Poly(ethylene-acrylic acid) copolymer (E^8heP).

9. Oxidized polyethylene (OPE): This polymer is used to provide compatibility between polyalkylenes and water-soluble polymers or to modify the release properties of other water-soluble polymers such as PEG and PEO. Ru.

10. Polyethylene glycol-fatty acid ester: This type of polymeric surfactant provides a wide range of melting points and water solubility/dispersibility depending on the chain length of the polyethylene glycol and fatty acid. For example, polyethylene glycol monolaurate with an average molecular weight of 6000 has a melting point of 61°C.
Polyethylene glycol dilaurate, which is highly water-soluble and has an average molecular weight of 400, has a melting point of 18° C. and is not water-soluble but water-dispersible. These materials can be used to form two coatings that are compatible with each other but have different properties. PEG 6000 monolaurate may be used to form a water-soluble first coating with high mechanical strength, and PEG 400 dilaurate may be applied as a second coating to constitute a moisture barrier.

The following are specific examples of coating material blends that have been found to be useful.

1. Blends of soap/fatty acid/polymer, especially sodium stearate/lauric acid/ethylene acrylic acid copolymer in a weight ratio of 0.5-2.0:0.5-2.0:1.

2. Fatty alcohol ethoxylate/polymer blends, especially blends in which the amount of polymer is less than the fatty alcohol ethoxylate and is polycaprolactone or ethylene acrylic acid copolymer.

In the first of these two blends, the presence of the polymer was found to reduce the melting point, crystallinity and crystal size. The presence of polymer also leads to changes in water solubility. In the second blend, the presence of said polymer or another polymer was found to increase the melting point and hardness of the coating material.

Picture] Sushi Kai- A wide variety of materials can be used for the solid dispersed phase.

Specific examples include sodium chloride, sodium carbonate, organic peroxy acids and their salts (bleach), tetraacetylethylenediamine (TAED, a low temperature bleach precursor), sodium perborate (bleach), dichloroisocyanuric acid I The particles of the solid dispersed phase are organic or They may be inorganic porous particles and may contain liquids held between the particles or within the pores within the particles. Specific examples of solid dispersed phase particles include anhydrous sodium carbonate and porous silica. Liquids that can be supported on the porous dispersed phase include antifoaming agents and fragrances.

1111 Various materials can also be used in this liquid dispersed phase. Specific examples include silicone oil (used as a fabric softener);
and viscous dispersions of hydrophobized silica in silicone oil (used as antifoaming agents).

The function of the crumple agent is to locally or globally increase the total amount of dispersed material until the melt becomes unstable. The crumple agent must be such that it is solid at the temperature at which crumple formation occurs and does not dissolve in the coating material at the processing temperature. Subject to these conditions, a wide range of substances can be used as scrambling agents.

The crumple agent can be an inorganic particulate solid material or particles of high molecular weight polymer. Other organic or inorganic particulate solid materials may be used, but are usually more expensive and should not be used unless they serve a specific function in the final product, as discussed below. Crosslinked polymer powders and polymer latex particles may also be considered crumple agents. The effectiveness of the crumple agent increases with decreasing particle size.

Examples of crumple agents include silica, anionic or cationic clays, zeolites, talc, sodium carbonate, sodium bicarbonate, calcite, polyethylene oxide (PEO), sodium carboxymethyl cellulose, starch, cellulose acetate, fine quality. Examples include cellulose.

If there is a substance used as the solid dispersed phase, the amount of that substance can be increased and the increased amount can be used as the crumple agent.

Since many crumple agents attach to the surface of particles formed by crumple formation, they can also be used to modify the surface properties of these particles. For example, a crumple agent may impart hydrophilicity or hydrophobicity and/or reduce gas and vapor permeability of the coating.

The crumple agent in the dual-coated particles may have several important functions. For example, in dual-coated particles, the majority of the crumple agent may be located on the outside of the single-coated particle, ie, the particle before being coated with a second coating. When the second coating step is carried out by the method of the present invention (as opposed to conventional methods such as fluidized bed coating), a different crumple agent (non-rubber) is used to cause crumple formation in this second coating step. activity) may be used.

Other functions that crumple agents may perform in dual-coated particles are described below.

1. The crumple agent can absorb water penetrating through the outer coating, thus acting as a water reservoir to prevent water from acting on the encapsulating material during storage or delaying the release of the solid dispersed phase. I can do it. Crumpled agents that can function as water reservoirs are water-soluble or water-swellable polymers such as sodium carboxymethylcellulose, clay silica gel, and inorganic salts that recrystallize with large amounts of water of crystallization. Salts of this type include sodium l-ribolyphosphate, sodium pyrophosphate, sodium or-I-phosphate, mono-lium glass polyphosphate, aluminum sulfate^1□(SO,)3, and sodium carbonate.

2. In addition to the above anhydrous salts, Lil, LiBr, LiCl
Inorganic salts such as AlCl and AlCl generate large amounts of heat upon hydration. The heat generated when water is absorbed through the outer coating and the crumple agent hydrates can serve to heal surface cracks, thus increasing the storage stability of the capsule.

3. When water-swellable materials such as modified starches, cellulose, cross-linked polymers of the type or clays are used as crumple agents, these materials act as trigger agents.
These crumple agents expand and disrupt the outer coating when they come into contact with water that permeates through the voids in the outer coach-in.

4. The crumple agent can also be a chemical that is to be continuously released before the primary solid dispersed phase encapsulated by the first coating.

L'beard surfactants can be used as or included in coating materials, as described above. In addition to such uses, surfactants may also be used to emulsify liquid dispersed phases or to modify the surface properties of solid dispersed phases. For emulsions containing silicone oils or silicone defoamers, silicone glycol copolymer surfactants DC190, DC193 from Dam Coning
and DC198 (particularly DC193) were found to be suitable surfactants. Therefore, surfactants DC193 and DC198 were also used in the polymer phase, which is the coating material. The presence of surfactants to modify the surface properties of the solid phase is particularly applicable when the solid is incompatible with the coating material.

If an outer coating is used, i.e. if the previously coated particles are further coated with a second coating, this outer second coating may be heated at room temperature (or whatever temperature the end-end particles are stored at). It may be formed of any coating material that is fixed with. Examples of materials that can be used as outer coatings include paraffin wax and poly(
caprolactone) diol, poly(caprolactone) 1
~liol or a mixture thereof. Water soluble polymers such as polyethylene glycol may also be used.

11t'' The central step of the operation is crumplement into a particle state. This consists of mixing a melt of organic polymeric material containing a dispersed phase and then crumpling the melt by cooling, adding a crumple agent, or a combination of these two methods.

If a liquid dispersed phase is used, this phase is preferably first emulsified into the coating material in a mixing device suitable for forming an emulsion. The temperature must be above the melting point of the coating material and, if desired, the liquid dispersed phase can be preheated above this temperature before introduction into the mixing device. The liquid dispersed phase may be mixed with a surfactant prior to mixing with the coating material.

In one preferred procedure, the coating material and (if necessary) supplementary surfactant are placed in a suitable mixer;
Heat to a temperature above the melting point of the coating material.

If a solid dispersed phase is used, this phase is then placed in a mixer and mixed with the molten polymeric material to form a homogeneous melt. This operation is also carried out at a temperature above the melting point of the polymeric material and, if desired, is preheated before adding the solid dispersed phase to the mixer. (In order to form a homogeneous melt here, the order of introduction into the mixer can usually be reversed if desired.) The temperature of the mixture is then lowered to a temperature slightly above the melting point of the coating material. This temperature is suitably 5° C. higher than the melting point of the coating material. A crumple agent is then added and the resulting mixture is further cooled. This operation is effective by adding about 65% of the crumple agent while maintaining the temperature slightly above the melting point of the polymeric material and then beginning to cool without adding the remaining crumple agent. It has been found. Melt crumple usually begins before all of the crumple agent is added, but continued addition of crumple agent can complete the process and further promote crumple formation, forming smaller particles. . Mixing is preferably continued until the temperature has fallen to 30° C. below the melting point of the coating material.6 If a smaller particle size is desired, the resulting particulate material may be subjected to a milling process at this point.

If the dispersed phase consists of a porous solid that has absorbed liquid, it may be desirable to prevent large stresses from developing during mixing. This is because large stresses can cause the porous solid material to fracture and release the absorbed liquid. For this purpose, it is preferable to reduce the mixing rotational speed.

Preferably, the molten coating material is added in portions onto the solid dispersed phase until the melt begins to form, and then cooling is initiated and the crumple agent is added without waiting for the melt to become homogeneous. Good.

The process of the invention may be carried out in a batch process, for example using a Z-blade mixer, or in a continuous process, for example using a twin-screw extruder with two or more material introduction zones. In the quartering method, crumpleing may occur in a different device than that used for initial melt formation.

Examples of the present invention are shown below. Percentages and amounts are by weight unless otherwise indicated.

These embodiments are categorized as follows.

Examples 1,1 to 1.23 are basic method descriptions, Examples 2.1 to 2.2 are examples of coating the solid dispersed phase with a pre-coating, and Example 3.1 is a description of the basic method. Examples 4.1 to 4.4 relate to dual coating processes in which the solid dispersed phase is melted during processing; Examples 4.1 to 4.4 relate to dual coating processes in which the solid dispersed phase is not melted.

In Examples 3.1 and 4.1-4.4, the outer coating is water insoluble and has a lower melting point than the first coating. Examples 5.1 to 5.5 are examples in which both a liquid dispersed phase and a solid dispersed phase are used, and Example 6.
Nos. 1 to 6.6 are examples in which other coating materials were used.

Some discussion of particle size and properties has also been provided.

Many substances are referred to by trade name or abbreviation. The legend is shown below.

Coating/PEG: Polyethylene glycol, the number after PEG represents the molecular weight (Mud). Manufactured by Fluka A.

PEO: Polyethylene oxide, the number after PEO represents Mw. Manufactured by Aldrich.

pvp: polyvinylpyrrolidone, the number after PvP represents Mw. Manufactured by Aldrich.

PCL: 8C680: 8C400: Poly(caprolactone), melting point = 60°C, AIdric
Manufactured by h company.

Oxidized polyethylene (Mu+4000), ^l Iie
Manufactured by d-Signa1.

Ethylene-vinyl acetate copolymer, Mw=3500, vinyl acetate content 30%, ^l l iedSigna1
Made by company.

8C5120: Ethin-acrylic acid copolymer, 3500, acid value 420II+g KOH/g, ^ll
Manufactured by iedSigna1.

MII+ Rigiclex XGR791: High density polyethylene homopolymer, Mwl, 1xlO5
, manufactured by BP Chemica1.

P.C.L. Diol: poly(caprolactone) diol, Melt point 45℃, ^ Manufactured by clrich.

Go to P^ zoooo: Poly(acrylic acid), the number after FAA does not represent M.

^1 Manufactured by ddrich.

paraffin Wax (49°C): wax with a melting point of 49°C, Manufactured by Fisons.

PE0 6000 ML: Polyethylene glycol (molecular weight: 6000) monolaurate, melting point: 61°C, HLB=19.2 (water soluble),
5tephan Manufactured by Europe.

1'EG 6000 DS; Polyethylene glycol (molecular weight: 6000) distearate, melting point: 55°C, HLB: 18.4 (water soluble)
, manufactured by Courtaulds Chemicals.

PEG 200 DS = Polyethylene glycol (molecular weight 200) distearate, melting point = 34°C, HLB = 5.0 (dispersed in water at high temperature), manufactured by CourtauldsCh6@1cals.

5ynperonic ^7: Ethoxylated alcohol, °C, II L
It・12.2 (water dispersible), manufactured by Chemicals.

Pour point 21 hell1 Episode J Takuosan” [ TAED: tetra-acetylethylenediamine, Manufactured by BDH.

5DCC^ni Sodium dichloroisocyanurate hydrate, Manufactured by BD11.

^rosurf TΔ-100 distearyldimethylammonium chloride (cationic surfactant with a melting point of 75°C),
Manufactured by 5herex.

Light soda ash: Anhydrous porous sodium carbonate (manufactured by IC1), particle size 420
pm, total push amount 4.14ca37g.

Microsi GP: Porous silica (Crosr″1eld Chemica
(manufactured by one company), particle size 10pm, BET surface area = 210m2/
g.

“Kuu Sainin Oturu” J Town ^erosi1 380・ Pyrogenic silica (manufactured by Degussa), 7 nm.

Particle size: ＾erosil R972: Pyrogenic hydrophobized silica (manufactured by Degussa), particle size: 1
6ni.

^vicel PH-101: Microcrystalline cellulose (FMC) degree/501m.

Corp.), grain starch: particle size 51Im (manufactured by BD11).

Bentone SD-2L: clay, Particle size <lIIm(NL (manufactured by Chemica 1).

TSPP: Tetrasodium birophosphate, manufactured by BDH.

Monium chloride, manufactured by Akzo.

DC193: Silicone glycol copolymer Da
m Manufactured by Corning.

5pan 85: Sorbitone trioleate (nonionic surfactant), manufactured by IC1.

Operations were carried out using various solid dispersed phase materials and various organic coating materials. In most of these examples no surfactant was needed and therefore was not used. All procedures were the same except for Examples 1.22 and 1.23.

The coating material was melted in a Z-blade mixer equipped with heating and cooling equipment. The solid dispersed phase was added at a temperature of about 10-15° C. above the melting point of the coating material and cooling of the mixture was started after a homogeneous mixture was obtained. Once the temperature was within 5° C. of the melting point of the coating material, 65% of the crumple agent was added and mixing continued while maintaining the temperature to ensure complete incorporation of the crumple agent. The mixture formed large agglomerates around this step. Then, the remaining crumple agent was added.

The driving torque, which represents viscosity, was monitored. This torque steadily increased as the melt cooled and approached the melting point of the coating material. Addition of the crumple agent caused a sharp drop in mixer torque.

The mixing operation continued for 30 minutes without reducing the mixer temperature to 30° C. below the melting point of the coating material.

Examples 1.22 and 1.23 used a porous solid dispersed phase that had absorbed liquid. The dispersed phase in Examples 1 and 22 was light soda ash that had absorbed a silicone antifoam agent;
．． The dispersed phase of No. 23 is perilla that has absorbed fragrance.

In these two examples, at the beginning of the operation, the solid dispersed phase was placed in a two blade mixer at a temperature of about 10° C. above the melting point of the coating material. The coating material was added gradually at a temperature 5° C. above its melting point. Once it was observed that a melt was beginning to form due to the formation of large aggregates of the dispersed phase, the crumple agent was added and cooling of the mixer began.

Mixing was continued until the temperature dropped to 30'C below the melting point of the coating material.

In both of these examples, the final product formed had the appearance of a dry particulate solid warehouse.

The substances (materials) used in Examples 1, 1 to 1.23 are shown in Table 1 below. The amounts of these substances are given in weight percent relative to the final granular composition.

The porous dispersed phase used in Example 1.23 was prepared by first coating porous silica (Microsil CP) with a methoxyl-functional silane coupling agent to form a nonolayer with a hydrophobic surface. It was manufactured by the method. The coupling agent is γ-methacryloxypropyltrimethoxy-silane (^174, Unio
(manufactured by nCarbide). Microsil
(:P has a large surface density, so a large amount of silane is required to completely cover the surface, and complete coverage of the surface reduces the pore density of the silica.
Only the surface and outermost pores of the GP were coated in the following manner.

Microsil GPL7) Maximum water holding capacity was measured to be 2.2 g water/g silica. (Adding more water reduced the free flowability of the powder.)
The silica particles were filled with water to 80% of their holding capacity.

Sufficient amount of Δ174 silane coupling agent is dissolved in n-pentane to form a solution capable of filling the remaining pores not filled with water (i.e., 20% of the maximum absorbing capacity of the silica). did. The above n
- The powder lost its free-flowing state when the pentane solution was added. The rhopentane was then evaporated at room temperature and silane^174 was polymerized at a temperature of 38° C. and 70% relative humidity. The resulting surface-hydrophobized powder was dried under vacuum at 60° C. for 24 hours, after which the perfume was absorbed.

2.1 and 2.2 In these examples, the surface of the solid dispersed phase was coated with a pre-coating. The overall procedure was to first mix the solid dispersed phase with the appropriate precoating material (ie, surfactant or surfactant-containing liquid) in a two-blade mixer at elevated temperature Ts. After mixing for a sufficient period of time at temperature Ts, the temperature of the mixer was lowered to about 10° C. above the melting point of the primary (polymer) coating material and the molten polymer was added to form a homogeneous mixture. lowering the temperature of this Φ mixture to a temperature Tc about 5° C. higher than the melting point of the polymer;
65% of the crumple agent was added. Mixing was continued to fully incorporate the crumple agent. At this stage, the mixture began to form large agglomerates. Add the remaining crumple agent and increase the mixer temperature to 30' above the melting point of the polymer.
C lowered to a low value. Table 2 shows the composition of the coated particles produced by this method.

In Example 2.1, only a surfactant was used to achieve compatibility between NaCI and the polymer coating. In Example 2.2, the solid dispersed phase was coated with a liquid mixture comprising silicone oil and a surfactant that was compatible with the solid dispersed phase and the polymeric coating. The silicone oil serves to completely coat the surface of the dispersed phase and to keep the potentially reactive solid dispersed phase isolated during mixing with the polymer, which takes place at elevated temperatures.

Particles having the compositions shown in Table 3 were produced. In Table 3,
The temperatures within the two-blade mixer at various stages of operation are also shown. The operation in this case consists of two stages. 1st
In the coating step, the solid dispersed phase and the polymeric coating material are melted together to a temperature of approximately 1
Mixing was carried out at a temperature TMAX-1 that was 0°C higher. Once a homogeneous melt is obtained, this melt is brought to a temperature T slightly above the melting point of the first coating material. It was cooled to 1. A portion of the crumple agent was added to cause crumple formation. Mixing and cooling continued until the temperature was T8□8 below the melting point of the second coating material. The resulting granular product is subjected to a second coating stage.

In this second coating step, the temperature was increased to a temperature TMAX-2 approximately 5-10°C above the melting point of the second coating material, and the second coating material was added in a molten state at the same temperature TMAX-2 without continuing mixing. .

It is usually appropriate to reduce the temperature and/or add more crumple agent once particle agglomeration is observed. In this example, the crumple agent was further added at the temperature, after which the temperature was lowered at a rate of about 1°C/min to about 30°C below the melting point of the second coating material.

The particles formed included a solid dispersed phase encapsulated by a polymeric coating and an outer coating of another material formed over the polymeric coating.

Particles having the composition shown in Table 4 were produced. These particles have two coatings, the outer coating being water insoluble and having a lower melting point than the first coating material. In this regard, these examples are similar to Example 3.
．． Example 3.1 is similar to Example 3.1, except that in Example 3.1 the solid dispersed phase is melted together with the first coating material.

In the first coating stage, the first coating material was mixed with the solid dispersed phase at elevated temperature TMAX-1. After a homogeneous mixture has been formed, the melt is brought to a temperature T slightly above the melting point of the first coating material. 1 and added the crumple agent. Cooling was continued until the temperature reached T□A. In the second coating stage, the temperature of the particles obtained in the first stage was increased to TMAX-2 and at this temperature the second coating material was added. Mixing was continued until agglomerations of particles were observed. At this stage, the temperature is set to a temperature T slightly higher than the melting point of the second coating material. I lowered it to 2. Crumplement occurred with the addition of a small amount of crumple agent. Mixing was continued and these double coated particles were allowed to cool to room temperature.

In Examples 4.2 and 4.4, the crumple agent used in the first coating step can generate large amounts of heat and can act as a water reservoir when exposed to water.

Particles having the composition shown in Table 5 were produced. These particles contain both solid and liquid dispersed phases. In these particles, the polymeric material may contain a suitable surfactant, and the silicone oil or paraffin wax constituting the liquid dispersed phase may also contain a surfactant.

The overall procedure was to first heat a polymeric material with an (optionally included) surfactant to form a mixture of the two materials. The liquid dispersed phase was also heated separately with the (optionally included) surfactant to form a mixture of the two dispersed phases. After incorporating the optional surfactant, the polymeric material and liquid dispersed phase were heated and mixed together to form an emulsion.

Emulsification was carried out in a static mixer consisting of a series of short capillary tubes separated by flow dividers to prevent liquid channeling. The diameter D of the capillary, the length of the capillary, the entrance angle of the capillary φ1, the exit angle of the capillary φ2, the total flow of continuous and dispersed phases ff1Q and the number of capillary units N are determined by the following: small dispersed phase droplet particles with a narrow particle size distribution; (less than 101 m). Since the viscosity of the silicone antifoam agent and silicone oil used in Examples 5.1 to 5.5 is significantly higher than that of the continuous phase, an elongated flow region (elongation, al.
Nou+ fields) are required. The static mixer has such a flow region, and the maximum shear rate Ss and elongation Emt at each stage are calculated according to the following formula.

Sm= (32Q/πDJ En+= (16Q/πD') sin(φi/2) i
4 (inlet) i = 2 (outlet) The above equation requires that the inlet angle/exit angle must be large (i.e. φi・φ2・18
0'), which also indicates that L/D must be small to reduce the pressure drop within the mixer. Emulsification was carried out under the following conditions: Number of capillary units N = 8, D
= 1mm, L/D=2, Em=3x 10's
The emulsion delivered from the final capillary unit is sprayed onto the solid dispersed phase heated to the temperature of the emulsion in a Z-blade mixer. Mixing was continued until a homogeneous mixture was obtained.

Thereafter, as in Examples 1.1 to 1.21, the melt was cooled to a temperature Tc slightly higher than the melting point of the coating material, and 65% of the crumple agent was added, at which point agglomeration was observed. The melt was then cooled to about 30°C below the melting point of the coating material before the remaining crumple agent was added.

The use of ethylene acrylic acid copolymer (AC5120) in the coating material of Example 5.5 proved to be very useful. First, this copolymer acted as a very effective emulsifier in emulsifying the tricone antifoam. Second, the copolymer increases the viscosity of the continuous phase in the emulsion, thus reducing the risk of double emulsion formation and also reducing the size of the dispersed silicone antifoam. Furthermore, this copolymer also has the effect of increasing the hardness of the continuous phase after solidification.

Grain "L" It has been found that the average particle size and particle size distribution of the coated particles depends on a number of factors, such as:

(1) Characteristics of the raw materials, such as particle size of the solid dispersed phase,
(2) Operating conditions, such as the rotational speed of the mixer blades, the temperature of the mixer when adding the crumple agent, and the type of mixer.

Table 6 shows the average particle size and particle size distribution of the particles produced in the various examples above.

Release Characteristics The release characteristics of various encapsulated particles in water were investigated by monitoring the concentration of dispersed phase material in water as a function of time. The final dispersed phase material concentration after an extended period of time was also determined. The release profile of the particles is here: (1)
(Optional) delay time t before the start of release. , (2) the initial release rate R, (% release rate per unit time), and (3) the half-life of the encapsulated dispersed phase, 1++. These values are shown in Table 7. As is clear from this table, the lag time, initial release rate and dispersed phase half-life can vary over a fairly wide range.

X1%+6 Coated particles were prepared using the same general procedure as Example 1.22, but using a different coating material. In some cases, the coated particles were further coated with a second coating material. Unlike Example 4, both of these coating materials were well water soluble.

The release of antifoam from the resulting particles was investigated by monitoring the change in surface tension at 25° C. and/or the foam-controlling effect of the particles.

The results are shown in Table 8.

The particles of Examples 6.2 and 6.3 were also mixed in a powder mixer for 15 minutes to test the durability of the coating. Antifoam release was unchanged for particles of example 6.3 and for example 6.2.
particles, there was only a small increase. The coating of these particles will therefore be durable.

Claims (15)

[Claims] (1) A method for coating or encapsulating solid particles and/or liquid droplets, the method comprising: forming a melt of coating material containing the particles and/or droplets as a dispersed phase; destabilize said melt by addition and/or cooling of said melt, thereby rendering said melt a particulate material comprising particles consisting of said coating material and particles and/or droplets of a dispersed phase embedded therein. and a second step of decomposing. 2. The method of claim 1, wherein the coating material is an organic polymeric material, a wax, a soap, a non-soap surfactant, a fatty acid, or a mixture of these materials. (3) The method according to claim 2, wherein the coating material is water-soluble or water-swellable. (4) The method of claim 2, wherein the coating material is water-insoluble. (5) The method according to any one of claims 1 to 4, wherein the solid particles encapsulated by this method are themselves water-soluble. (6) A method according to any one of claims 1 to 5, wherein the solid particles encapsulated by this method are bleaching compounds. 7. A method according to claim 1, wherein the solid particles encapsulated by the method are bleach-activated substances. (8) A method according to any one of claims 1 to 5, wherein the liquid droplets encapsulated by this method are antifoam agents and/or fabric softeners. (9) A method according to any one of claims 1 to 8, wherein both liquid droplets and solid particles are encapsulated together. (10) A method according to any one of claims 1 to 5, wherein the solid particles encapsulated by this method are porous and absorb liquid therein. (11) The method according to claim 10, wherein the liquid is a fragrance. (12) The method according to claim 10, wherein the liquid is an antifoaming agent. 13. The method of claim 1, wherein the particles of particulate material are further coated with an outer coating. 14. The method of claim 13, wherein the formation of the outer coating is carried out by repeating the steps of claim 1 with the product particles as a dispersed phase. (15) The method of claim 13 or 14, wherein the particles coated with the outer coating are water-swellable.