CN1105170C

CN1105170C - Detergent composition comprising clay flocculating polymer with particle size less than 250 microns

Info

Publication number: CN1105170C
Application number: CN96197708A
Authority: CN
Inventors: M·K·芬内; J·韦弗斯
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1995-09-01
Filing date: 1996-09-03
Publication date: 2003-04-09
Anticipated expiration: 2016-09-03
Also published as: BR9610465A; CN1200142A; WO1997009406A1; MX9801690A; DK0865480T3; JP3894953B2; EP0865480A4; DE69622744D1; JPH11515039A; ES2176486T3; EP0865480B1; DE69622744T2; PT865480E; ATE221570T1; EP0865480A1

Abstract

The invention relates to a granular detergent composition comprising (i) a softening clay and (ii) a clay flocculating polymer, and to a process for making the composition. The composition is particularly useful in 'softening-through-the-wash' products. The clay flocculating polymer is sieved or ground such that at least 95 % by weight of the clay flocculating polymer has a particle size of less than 250 micrometers, and preferably less than 150 micrometers, before adding it to the granular detergent composition.

Description

Detergent composition comprising clay flocculating polymer having particle size less than 250 microns

The present invention relates to particulate detergent compositions comprising (i) softening clay and (ii) clay flocculating polymer, and to a process for preparing the compositions. The compositions are particularly useful in "softening during the wash" products.

Clay flocculating polymers, such as high molecular weight polyethylene oxide, are commercially available as 100% active powders.

EP-A-0299575, published on 18/1/1989, discloses granular detergent compositions comprising ｃA softening clay and ｃA polymeric clay flocculating polymer. It is stated that the polymeric clay flocculating agent may be added in various ways during the preparation of the particulate detergent composition. It may be added to the crutcher mixture prior to spray drying; or sprayed as a solution in water or organic solvent onto the granular detergent; or dry-blended in granular form with the granular detergent. The application does not mention the preferred particle size of the clay flocculating polymer.

However, when the polymeric clay flocculating polymer is dry blended with a granular detergent, undesirable non-uniform clay deposition or residue is observed. Non-uniform deposition refers to visible clumps of clay deposited on the surface of the fabric. This is caused by the rapid flocculation of the clay particles prior to clay dispersion. This results in the formation of clay lumps that deposit on the surface of the fabric. The residue is caused by the formation of gels upon contact with water at high local concentrations of clay flocculating polymer present in the formulation, which leads to poor product dispersibility and increased risk of product deposition on fabrics.

In addition, clay flocculating polymers, when handled in particulate form, create handling and explosion problems.

Summary of The Invention

According to the present invention, undesirable non-uniform clay deposition and residue is avoided by screening or grinding the clay flocculating polymer such that at least 95% by weight of the clay flocculating polymer has a particle size of less than 250 microns, preferably less than 150 microns, prior to addition to the particulate detergent composition.

The clay flocculating polymer is preferably a polyethylene oxide having an average molecular weight of from 100,000 to 10,000,000, more preferably from 150,000 to 800,000.

In another aspect of the present invention there is provided a process for the preparation of a granular detergent composition comprising the steps of pre-mixing a clay flocculating polymer with a powder selected from the group consisting of aluminosilicates, silicates, carbonates, citrates, phosphates or mixtures thereof and subsequently mixing the pre-mix with other detergent components.

Thepre-mix is preferably composed of clay flocculating polymer and aluminosilicate in a ratio of 1: 20 to 20: 1.Detailed description of the inventionSoft clay

The soft clay may be unmodified or organically modified. The clay, which is not organically modified, can be described as a swellable three-layer clay, i.e. aluminosilicate and magnesium silicate, the clay having an ion exchange capacity of at least 50meq/100g of clay, preferably at least 60meq/100g of clay. The starting clay for the organically modified clay can be similarly described. The term "swellable" as used to describe clays relates to the ability of the layered clay structure to swell or expand when contacted with water. The three-layer swellable clay used in the present invention is a material that is geologically classified as a smectite. There are two different types of smectite-type clays that can be broadly distinguished by the number of octahedral metal-oxygen arrangements in the central layer for a given number of silicon-oxygen atoms in the outer layers. A more complete description of clay minerals is given in "clay colloid chemistry", h.van Olphen, John Wiley&sons (interscience publishers), new york, 1963, chapter six, especially pages 66-69.

The smectite (or smectite-like) clay family includes the following trioctahedral minerals: talc; hectorite; talc powder; sauconite; vermiculite; and the following dioctahedral minerals: (ii) prophyllite; montmorillonite; a chromium montmorillonite; and nontronite.

The clays used in these compositions contain cationic counterions, for example, protons, sodium ions, potassium ions, calcium ions, and lithium ions. One typically distinguishes clays based on a cation that is predominantly or exclusively adsorbed. For example, sodium clays are clays in which the adsorbed cation is predominantly sodium. The adsorbed cations can undergo an exchange reaction with cations present in the aqueous solution. A typical exchange reaction involving a smectite-type clay is represented by the following equation:

since in the foregoing equilibrium reaction, an equal weight of ammonium ion replaces an equal weight of sodium, one usually measures the cation exchange capacity (sometimes referred to as "base exchange capacity") in milliequivalents per 100 grams of clay (meq/100 g). The cation exchange capacity of a clay can be determined by several methods, including electrophoresis, exchange with ammonium followed by titration, or by the methylene blue method, all of which are fully described in Grimshaw "chemistry and Physics of Clay", pp.264-265, Interscience (19-1). Cation exchange capacity of clay materials and factors such as clay swellabilityTexture, charge of the clay (which in turn is determined at least in part by the lattice structure), and the like. For certain smectite clays, the ion exchange capacity of the clay can vary widely from about 2meq/100g of kaolin to about 150meq/100g, and greater.

Preferred smectite-type clays are sodium montmorillonite, potassium montmorillonite, sodium hectorite and potassium hectorite. The clays used in the present invention have a particle size of up to about 1 micron.

Any clay used in the present invention may be natural or synthetically derived. Clay flocculating polymers

Most clay flocculating polymers are rather long chain polymers and copolymers derived from monomers such as ethylene oxide, acrylamide, acrylic acid, dimethylaminoethyl methacrylate, vinyl alcohol, vinyl pyrrolidone and aziridine. Gums, such as guar gum, are also suitable.

Polymers of ethylene oxide, acrylamide or acrylic acid are preferred. These polymers significantly improve the deposition of fabric softening clays if their molecular weight is in therange 100000 to 10000000. Preferred are polymers having a weight average molecular weight of 150000 to 5000000.

The most preferred polymer is poly (ethylene oxide). The molecular weight distribution can be readily determined using gel permeation chromatography against narrow molecular weight distribution poly (ethylene oxide) standards. Method of producing a composite material

The particle size of the polymer is reduced by standard grinding operations or by physical sieving of the particles. The feedstock is then optionally mixed with a powder, such as a fine aluminosilicate (zeolite a), in a mixer and then added to the finishing process. The zeolite acts as a carrier for the polymer, aiding its dispersion in the preparation of the finished product.

Many types of particle size changing equipment can be used to reduce the average particle size of the clay flocculating polymer to below 250 microns. Continuous screening machines, such as Russel Finex and Mogenson shaker screens or continuous scraping screens. Intermittent screening operations involving the RoTap variable may also be used in small numbers. For larger scale operations, a continuous air jet mill may be used, which may simultaneously size and sort the material.

In a particular embodiment of the invention, the polymer particles may be treated by micronization to further reduce the average particle size. Other detergent ingredients

The particulate component of the present invention is typically incorporated into the final detergent product, especially products comprising softening clays. Other conventional detergent ingredients such as anionic and cationic surfactants, builders, bleaching agents, bleach activators, suds suppressors, enzymes (e.g., protease, amylase, cellulase, lipase), perfumes, brighteners, soil release polymers may generally be used.

Examples

In these examples, all percentages are by weight, unless otherwise indicated, using the following abbreviations: PEO (as received): polyethylene oxide polymer, supplied by Union carbide under the tradename WSRN 750. Typical particle size distribution:

2% greater than 710 μm

8% between 710 and 500 microns

20% between 500 and 250 microns

30% between 250 and 150 microns

40% less than 150 micron PEO (sieved): such as above, but subjected to a size reduction process to remove 95% of the material greater than 150 microns. Typical particle size distribution:

at least 100% of the particles are smaller than 300 microns

At least 95% of the particles are smaller than 150 μm

At least 50% less than 106 micron zeolite a: supplied by Industrial Zeolite ltd, Thurrock, England. Typical average particle size: 2-10 microns. Light soda ash a: light density sodium carbonate, usually 97% pure carbonate, has an average particle size of about 100 microns and an aerated density of 550g/l on average.

Example 1

The PEO samples (as received) were converted to PEO (sieved) on a 150 micron sieve by the RoTap batch sieving method. The resulting polymer was mixed with a blend of the following ingredients in a small food processor in the ratios: 1 part of PEO (sieved) to 2 parts of zeolite A was mixed to a homogeneous state.

The PEO/zeolite a pre-mix was mixed in a batch rotary mixer with the granular components of the "soft-during-wash" detergent composition as shown below. And then the liquid component is sprayed thereon. The final composition has excellent clay deposition and softening properties.

Example 1 (percentages by weight)

PEO/Zeolite A Pre-mix 0.5

Soft clay 18

Anionic surfactant agglomerates 26

Cationic surfactant agglomerates 6

Nonionic surfactant 3

Sodium percarbonate 13

Phyllosilicate/citric acid 12

Zeolite 4

Bleach activator particle 4

Suds suppressor 3.5

Sodium carbonate, enzyme, perfume, soil release polymer,

Whitening agent and other minor components to 100

Example 2

Example 1 was repeated except that the size reduction step was accomplished by passing the PEO (as received) through a continuous Russel Finex vibratory screening system equipped with a 150 micron screen.

Example 3

Example 1 was repeated except that the size reduction step included grinding the PEO (as received) in a small batch coffee mill, followed by completion of the RoTap batch screening. This avoids any PEO loss (as is).

Example 4

Example 1 was repeated except that the size reduction step was performed by passing the PEO (as received) through a standard non-oscillating screen plate equipped with a 150 micron screen and fitted with rotating brushes to improve screening efficiency.

Example 5

Example 1 was repeated except that the size reduction step was performed by passing the PEO (as received) through a standard air jet mill so that only particles smaller than 150 microns were entrained in the air stream, removed and collected. This approach avoids the loss of PEO (as is) and is useful for large scale volume needs.

Example 6

Example 4 was repeated except that the PEO (sieved) was mixed with zeolite A in a batch verto mixer or similar device which incorporated a concentric mixer with a screw rotating about its own axis which was simultaneously running around the mixing chamber.

Example 7

Example 6 was repeated except that the resulting premix contained 1 part: 1 part of PEO (sieved) is mixed with zeolite A.

Example 8

Example 6 was repeated except that the resulting premix contained 1 part: 10 parts of PEO (sieved) with zeolite A.

Example 9

Example 8 was repeated except that the resulting premix contained 1 part: 10 parts of PEO (sieved) with fine light soda ash.

Example 10

Example 6 was repeated except that the premix was added directly to the continuous detergent preparation process before any liquid was sprayed.

Example 11

Example 6 was repeated except that the premix was dusted on the detergent surface prepared by the continuous preparation method after spraying any liquid.

Claims

1. A particulate detergent composition comprising (i) a softening clay and (ii) a clay flocculating polymer, characterised in that at least 95% by weight of the clay flocculating polymer has a particle size of less than 250 microns.

2. A granular detergent composition according to claim 1 in which at least 95% by weight of the clay flocculating polymer has a particle size of less than 150 microns.

3. A granular detergent composition according to claim 1 or 2 wherein the clay flocculating polymer is a polyethylene oxide having an average molecular weight of from 100,000 to 10,00O, 000.

4. A granular detergent composition according to claim 3 in which the clay flocculating polymer is a polyethylene oxide having an average molecular weight of from 150,000 to 800,000.

5. A process for making a granular detergent composition according to any of claims 1 to 4 further comprising a powder selected from aluminosilicate, silicate, carbonate, citrate, phosphate or mixtures thereof, the process comprising the steps of pre-mixing the clay flocculating polymer with the powder to form a pre-mix, and subsequently mixing the pre-mix with other detergent ingredients.

6. A process according to claim 5 in which the premix consists of the clay flocculating polymer and aluminosilicate in a ratio of from 1: 20 to 20: 1.