Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Solid – shaped macroscopic article or structure
Reexamination Certificate
2000-03-14
2001-12-11
Delcotto, Gregory (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Solid, shaped macroscopic article or structure
C510S120000, C510S141000, C510S220000, C510S224000, C510S349000, C510S446000, C510S447000, C510S451000, C510S452000, C510S475000, C510S499000
Reexamination Certificate
active
06329334
ABSTRACT:
BACKGROUND AND PRIOR ART
The invention relates to the use of crosslinked polyvinylpyrrolidone as an additive to compact, particulate detergents and cleansers for the purpose of increasing the rate of disintegration thereof when brought into contact with water, to the particles of crosslinked polyvinylpyrrolidone having a particle size of from 50 to 400 &mgr;m, to a process for the preparation of the compact, particulate detergents and cleansers, and to the compact, particulate detergents and cleansers themselves.
Dense or compact detergent and cleanser compositions are prepared by various agglomerating, compacting or pelletizing techniques. In the case of compact detergent and cleanser products present for example in the form of pellets, it is difficult to establish the correct balance between adequate strength properties and sufficiently rapid dissolution or disintegration thereof when subjected to the action of water. For example, detergent pellets which have been placed in the run-in chambers of a washing machine, must disintegrate over a period of less than one minute after being contacted with water. When there is only a slight degree of compaction of the detergent pellets a satisfactory rate of disintegration is achieved, in use, but frequently at the expense of the desired breaking resistance or abrasion resistance. Pellets thus prepared have only a small breaking resistance and tend to crumble and break to pieces during transport. On the other hand, excessive compaction or compression exerted during production of detergent pellets leads to unsatisfactorily long disintegration or dissolution times of the detergent pellets in use.
Compact or ultracompact detergents and cleansers are known, cf EP-A 340,013, EP-A 0,518,888, DE-A 19,649,560 and DE-A 19,649,565. In order to improve the rate of dissolution of particulate detergent formulations, use is made of solubilizing additives comprising, for example, copolymers of hydrophobic and hydrophilic monomers, such as copolymers of styrene and acrylic acid, cf WO-A 97/46657. According to the statements made in WO-A 97/46529 the rate of dissolution of particulate washing formulations is achieved by the use of, for example, addition products of ethylene oxide and/or propylene oxide and polyols.
Methods of producing pharmaceutical tablets reveal numerous possibilities for the preparation of pellets showing the desired strength properties and disintegration times. The main active mechanisms causing the disintegration of pellets are described to be wetting, capillary response (wicking) and swelling, cf Drug Development and Industrial Pharma, Vol. 6 (5) 511-536 (1980). Of the products which improve the solubility of tablets, mention has also been made of chemically crosslinked, swelling products such as microcrystalline crosslinked carboxymethylcellulose, crosslinked sodium carboxymethylstarch or crosslinked polyvinylpyrrolidone (cf Volker Buehler, Kollidon—Polyvinylpyrrolidone for the pharmaceutical industry, BASF, August 1993, pp 156 et seq).
By reason of the content of non-ionic surfactants and other low-melting wax-like, plastically deformable compositions in detergents, the addition of tablet bursters, which are known from pharmacy, to compact detergents and cleansers is rarely successful, particularly in the case of compact detergents used for washing laundry goods.
It is known that compact detergents and cleansers (shaped particles showing detergent and cleanser activity) have an increased rate of disintegration when they contain bursting agents in a special, granulated form, as are known in pharmacy and are capable of increasing the porosity or capillarity of the shaped particles and possess high adsorption capacity for water, DE 197 10 254 A1).
Compact detergents and cleansers prepared in this manner do indeed show an increased, but not sufficiently high, rate of disintegration, particularly in the case of compact detergents and cleansers which have been subjected to relatively high compacting pressures to increase their dimensional stability and breaking resistance. Furthermore, the thus prepared compact detergents and cleansers suffer from the drawback that the bursting agent must be converted to a granular form in an elaborate process step prior to compaction.
BRIEF SUMMARY OF THE INVENTION
It is thus an object of the present invention to provide additives which further increase the rate of disintegration of compact, particulate detergents and cleansers and do not suffer from the above drawbacks.
This object is achieved in the present invention by the use of crosslinked polyvinylpyrrolidone as an additive to compact, particulate detergents and cleansers to increase the rate of disintegration thereof when brought into contact with water, the particles of the crosslinked polyvinylpyrrolidone having a particle size of from 50 to 400 &mgr;m.
By compact, particulate detergents and cleansers we mean, for the purposes of the present invention, shaped particles showing detergent or cleanser activity, in particular pellets such as detergent pellets, dishwashing pellets, bleaching pellets, stain removing pellets or water-softening pellets, in particular detergent pellets for laundry goods for domestic use, in particular for machine use.
The term “shaped particle” is not limited to pellets.
Theoretically, any three-dimensional shape, such as pellets, spheres, extrudates, rings, bars or scales are possible, such as can be imposed on the starting materials optionally by means of a surrounding container.
By crosslinked polyvinylpyrrolidone we preferably mean the crosslinked polyvinylpyrrolidone used as tablet bursting agent in the pharmaceutical industry, such as Kollidon CL® or Luvicross® (trade name of BASF Aktiengesellschaft, Ludwigshafen, cf Volker Buehler, Kollidon—Polyvinylpyrrolidone for the pharmaceutical industry, BASF August 1993, pp 156 et seq).
DETAILED DESCRIPTION OF THE INVENTION
The particles of the crosslinked polyvinylpyrrolidone used have a particle size of from 50 to 400 &mgr;m and preferably from 80 to 300 &mgr;m.
In accordance with the invention, preference is particularly given to the use of crosslinked polyvinylpyrrolidone,in which the particles of said crosslinked polyvinylpyrrolidone have a particle size of from 50 to 400 &mgr;m and preferably from 80 to 300 &mgr;m, and at least 10 wt % and preferably 15 wt %, more preferably 25 wt %, of the particles have a particle size of less than 200 &mgr;m.
In order to achieve this preferred particle-size distribution, the polyvinylpyrrolidone solids (Kollidon CL® or Luvicross®), which are produced in known manner so as to show a broad particle-size distribution, by polymerization, such as popcorn polymerization, and drying, are sorted directly and without further granulating steps to give the desired particle-size distribution by appropriate means of classification, such as by sifting or pneumatic classification. Drying is carried out in known manner, for example by drum drying.
The invention also relates to compact, particulate detergents and cleansers which contain the aforementioned crosslinked polyvinylpyrrolidone in amounts of from 0.5 to 20 wt % and preferably from 0.5 to 10 wt %, more preferably from 0.5 to 5 wt %, to increase the rate of disintegration thereof when they are brought into contact with water.
In a preferred embodiment, the particles of crosslinked polyvinylpyrrolidone have, in accordance with the preferred use thereof, a particle size of from 50 to 400 &mgr;m and at least 10 wt % of the particles have a particle size of less than 200 &mgr;m.
Compact, particulate detergents and cleansers have already been explained above. Preferred compact, particulate detergents and cleansers are shaped particles suitable for washing laundry goods, that is to say compact, particulate detergents and cleansers which contain, in addition to the crosslinked polyvinylpyrrolidone as proposed by the invention, any conventional constituents of detergents used for washing laundry goods.
The compact, particulate detergents and cleansers of the invention are made in known mann
Baur Richard
Bertleff Werner
Heinz Robert
Palm Peter
Ruchatz Folker
BASF - Aktiengesellschaft
Delcotto Gregory
Keil & Weinakuf
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