Polymeric matrix particle compositions containing coacervate pol

Details Polymeric matrix particle compositions containing coacervate pol Polymeric matrix particle compositions containing coacervate pol

1993-11-15

1996-02-20

Chaudhuri, Olik

Compositions

Water-softening or purifying or scale-inhibiting agents

25217412, 252DIG12, C11D 3386

Patent

active

054926467

DESCRIPTION:

BRIEF SUMMARY
This invention relates to the encapsulation of active ingredient (especially detergent enzyme) within polymeric material so as to protect the active ingredient from the ambient environment, for instance atmospheric moisture when the product is exposed to the air, or the liquid phase of a liquid detergent when the product is incorporated in such a detergent.
Numerous ways of protecting active ingredient from the ambient environment are known. Some rely on a wholly liquid system. In U.S. Pat. No. 4,801,544, aqueous micelles of enzyme and surfactant are emulsified into a hydrocarbon solvent. In U.S. Pat. No. 4,906,396, enzyme is dispersed in a hydrophobic fluid, such as a silicone oil.
More usually, the enzyme is protected by a solid phase. In U.S. Pat. No. 4,090,973, solid surfactant is used. Often, however, a polymeric material is used. The enzyme or active ingredient may be dispersed in a polymeric matrix or it may be encapsulated by a polymeric shell formed around a core containing the active ingredient.
The solid polymeric material can be made by polymerisation of monomeric material in the presence of the active ingredient, but this is generally undesirable and normally the solid polymer of the matrix or shell is formed by depositing solid polymer from a solution of polymer. The polymer can remain chemically unchanged during the deposition from dissolved to solid form, the deposition being due primarily to a change in the solvent composition or properties. Alternatively, deposition can be caused by, accompanied by or followed by a chemical change in the polymer, such as neutralisation, complexing with another polymer, or cross linking. The formation of a solid polymer shell in this manner from a solution of polymeric material is generally termed coacervation.
Typical techniques for forming a polymer shell are described in, for instance, GB 1,275,712, 1,475,229 and 1,507,739, DE 3,545,803 and U.S. Pat. No. 3,591,090.
A particular problem arises when the active ingredient is an enzyme, especially an enzyme suitable for incorporation in detergents, because of the difficulty of preventing the enzyme losing activity before use.
Many different ways of encapsulating enzymes have been proposed. Some do not include coacervation. For instance GB 1,377,725 contacts atomised droplets of an aqueous slurry of enzyme with particles of starch. However there is a risk that the resultant coating will be discontinuous. It is therefore preferred to form the coating or matrix by deposition of solid polymer from a solution of polymer in which the enzyme is dispersed, i.e. by coacervation.
For instance in U.S. Pat. No. 3,838,007 droplets of enzyme dispersed in an aqueous solution of, for instance, gelatin are dispersed into water and then cross linked, to give cross linked particles of the gelatin containing the enzyme.
In JP-A-61254244, a typical process comprises mixing enzyme powder and silica into an aqueous solution of polyvinyl alcohol or other suitable polymer, dispersing the aqueous suspension into a non-aqueous liquid and adding acetone, so as to deposit the polymer as a wall around the enzyme particles. The product is said to have a particle size of around 50 to 2,000 um.
In U.S. Pat. No. 4,898,781, a dispersion is formed of enzyme powder in propylene glycol and aqueous polyvinyl alcohol and this dispersion is then converted into particles by various techniques. In one technique, the dispersion is introduced as droplets into an aqueous solution of cross linking agent, thereby solidifying by cross linking the polyvinyl alcohol. In another technique, the dispersion is dispersed into a hydrophobic solvent and then heated so as to drive off water and solidify the polyvinyl alcohol. The products are said to have a size of 20 to 1,000 um. Other techniques are described. JP-A-63105098 includes similar process description and many of the examples are identical. It proposed that the particles of enzyme in a covering of polyvinyl alcohol should be homogeneously dispersed in a liquid or gel detergent.
EP-A-356,240 (and U.S. Pat

REFERENCES:
patent: 3843557 (1974-10-01), Fanger et al.
patent: 4677003 (1987-06-01), Redlich et al.
patent: 4777089 (1988-11-01), Takizawa et al.
patent: 5035900 (1991-07-01), Langley et al.
patent: 5281357 (1994-01-01), Morgan et al.
patent: 5324445 (1994-06-01), Langley et al.

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