CN1116400C - Process for preparing detergent agglomerates - Google Patents

Abstract

Free-flowing detergent agglomerates containing high concentrations of anionic surfactant are prepared in a process using ultra-fine particle builders.

Description

Process for preparing detergent agglomerates

technical field

The present invention relates to a process for the preparation of highly active detergent agglomerates with improved free flow properties.

Background of the invention

Laundry detergent granules comprise one or more surfactants (typically anionic) and one or more builders (typically phosphates, carbonates, zeolites, etc.). Detergent granules are generally manufactured by preparing a slurry of various detergent ingredients and spray drying the slurry to form granules. These products can also be prepared by agglomerating mixtures of surfactants and builders in a mixer. During the agglomeration, the anionic surfactant can be used in a neutralized form or introduced into the agglomeration process in acid form and neutralized in situ with a basic substance such as sodium carbonate. Optional detergent materials such as brighteners, soil release agents, etc. can be agglomerated with the surfactants and builders or can be mixed with the agglomerates after formation. In general, agglomeration produces higher density detergent products than those produced by spray drying.

A common problem encountered with various detergent agglomerates, especially those having a surfactant concentration of not less than 20%, is that they tend to exhibit some degree of stickiness (ie, poor free flow). To alleviate this problem, various glidants such as clays, talcs, zeolites or silicas are commonly used.

Typical examples of various prior patents relating to agglomeration processes for the production of detergent granules are: US Patent 5,133,924 (Appel), US Patent 5,164,108 (Appel), US Patent 5,160,657 (Bartolloti), UK Patent 1,517,713 (Unilever), European Specification 451,894 (Curis), US Patent 5,108,646 (Beerse et al.), European Patent Specification 351,937 (Hollingsworth et al.), and US Patent 5,205,958.

It is an object of the present invention to provide a process for producing detergent agglomerates with high surfactant concentration and improved free-flowing properties.

Summary of the invention

The present invention relates to a method comprising the steps of:

(a) preparing in a mixer a mixture of detergent components comprising:

(1) from about 20% to about 35% of a compound selected from the group consisting of anionic surfactants and acidic precursors of anionic surfactants;

(2) from about 0% to about 65% of polyphosphates, pyrophosphates, and mixtures thereof

Granular phosphate builders;

(3) about 6% to about 60% of particles selected from sodium carbonate, potassium carbonate and mixtures thereof

Carbonates, wherein when an anionic surfactant is used in (a)(1) before the acidic

In the solid state, the amount of carbonate is at least 2 times the amount sufficient to neutralize the acidic precursor; wherein at least about 20% of the total amount of components (2) and (3) satisfy 97% of the particles smaller than 50 microns and a particle size specification requirement with a median particle size of 5-20 microns, and

(b) agglomerating the mixture of step (a) in a second mixer to produce detergent agglomerates. Detailed description of the invention

In accordance with the present invention, we have found that during the preparation of anionic detergent agglomerates having a high anionic surfactant concentration (i.e. not less than 20%) and containing carbonate and optionally phosphate builders, if When at least 20% of the total (i.e. blended) amount of particulate carbonate/phosphate used to make the agglomerates meets the specification requirement of 97% of the particles are smaller than 50 microns and the median particle size is 5-20 microns, Improved free-flow characteristics are obtained. raw material

Anionic surfactants are an essential component of compositions prepared by this process. Such surfactants are well known in the art. Anionic surfactants useful in the present invention are preferably alkali metal (ie sodium and potassium) salts of alkylbenzene sulfonates or alkyl sulfates or mixtures thereof. Examples of other anionic surfactants that are also useful are paraffin sulfonates, alkyl glycidyl ether sulfonates, and alkyl ether sulfates (all having from about 8 to about 18 carbon atoms in their alkyl chains) alkali metal salts. The anionic surfactant raw material preferably has a moisture content of less than about 1.0%, more preferably less than about 0.5%. The amount of anionic surfactant is from about 20% to about 35%, preferably from about 20% to about 30%, based on the total amount of raw materials added during the process of the present invention.

Preferred alkylbenzene sulfonates for use in the present process include those having an alkyl moiety that is straight or branched, preferably having from about 8 to about 18 carbon atoms, more preferably from about 10 to about 16 carbon atoms of alkylbenzene sulfonates. The average chain length of the alkyl chains of the alkylbenzene sulfonates is preferably from about 11 to about 14 carbon atoms. Alkylbenzene sulfonates including branched chain alkyl groups are known as ABS. The all linear alkylbenzene sulfonate known as LAS is preferred because it is more biodegradable.

Preferred alkyl sulfates for use in the present process include those having an alkyl moiety that is straight or branched, preferably having from about 8 to about 24 carbon atoms, more preferably from about 10 to about 20 carbon atoms, even more Alkyl sulfates having from about 12 to about 18 carbon atoms are preferred. The average chain length of the alkyl chain of the alkyl sulfate is preferably from about 14 to about 16 carbon atoms. The alkyl chain is preferably straight chain. Alkyl sulphates are generally obtained by sulphating fatty alcohols prepared by reduction of glycerides of fats and/or oils from natural sources, especially from tallow or coconut oil.

Preferred anionic surfactants useful in the process of the present invention are also mixtures of alkylbenzene sulfonates and alkyl sulfates (whether mixed together or added separately during mixing). Mixtures having a ratio of alkylbenzenesulfonate to alkylsulfate of about 20:80 to about 80:20 are preferred, and those having a ratio of about 40:60 to about 60:40 are more preferred. Additional disclosure of anionic synthetic surfactants can be found in US Patent 3,664,961 (Norris, issued May 23, 1972), incorporated herein by reference. In practicing this method, the anionic surfactant can be introduced in its neutralized (i.e. alkali metal) form or in its unneutralized acidic precursor, as discussed hereinafter, in the latter case the acidic The precursor is neutralized by excess alkali metal carbonate.

Optionally, phosphates are used as builders in compositions made according to the methods herein. Phosphate builder materials useful in the process of the present invention are in granular form and consist essentially of water-soluble salts of polyphosphates (such as tripolyphosphate, hexametaphosphate, etc.) or pyrophosphates (such as sodium salt and potassium salt) or mixtures thereof. The moisture content of the phosphate builder raw materials is preferably less than about 2%, more preferably less than about 1%. The amount of phosphate builder is generally from about 5% to about 65%, preferably from about 15% to about 55%, more preferably from about 25% to about 45%, based on the total amount of raw materials added in the process of the present invention. %. Phosphate builder materials are generally supplied by their manufacturers in powder form, usually having a median particle size of from about 25 microns to about 50 microns. Carbonate raw materials are generally supplied by their manufacturers in granular form, typically having a particle size of about 25 microns to about 150 microns. The "asis" median particle size for polyphosphates and carbonates varies from source to source and from supplier to supplier. In order to use polyphosphate builders and/or carbonates in the present invention, they are ground to at least about 20%, preferably at least about 40%, of the total amount of phosphate/carbonate particles used in the process. 97% of the particles are smaller than 50 microns (preferably smaller than 40 microns) and the median particle size is 5-20 microns, preferably 10-20 microns according to specification. Either carbonate, phosphate or both can be ground to obtain an amount of total phosphate/carbonate particles within the desired particle size requirements. Preferably at least 40%, more preferably at least 70% of the particles should meet the required specifications. Typically all particles of phosphate and carbonate used in the process will be in the total size range of 5-300 microns. Grinding can be accomplished in conventional powder grinding equipment such as the ACM Classifier Mill (Hosokawa Micron Powder Systems). During or after milling, the granules can be classified, if desired, to ensure that the milled granules are within the required specifications for use. A MicronPulsaire Classifier (Hosokawa Powder Systems) can be used for classification.

A preferred phosphate builder for use in the present method is sodium tripolyphosphate (STPP), which is commercially available from, for example, FMC Corp. Another preferred phosphate builder is tetrasodium pyrophosphate (TSPP), which is commercially available from, for example, FMC Corp.

The process of the present invention employs, as a builder, a particulate alkali metal carbonate which preferably consists essentially of sodium carbonate or potassium carbonate or mixtures thereof. If an acidic precursor of an anionic surfactant is used in the process, the carbonate also acts as a neutralizing agent to convert the acidic precursor into an alkali metal salt. The moisture content of the alkali metal carbonate feedstock is preferably less than about 2%, more preferably less than about 1%. The amount of alkali metal carbonate is from about 6% to about 60%, preferably from about 10% to about 50%, more preferably from about 30% to about 40%, based on the total weight of the feedstock added to the process of the present invention .

In order to neutralize the acidic precursors of anionic surfactants, each carbonate ion (CO ₃ ⁼ ) must react with two acidic hydrogens (H ⁺ ). From this reaction, the amount of carbonate theoretically required to neutralize the acidic precursor of the anionic surfactant can be determined. When an acidic precursor of an anionic surfactant is used in the process, the amount of carbonate added to the process is at least about twice the amount theoretically required to neutralize the acid. Preferably the amount of carbonate is from about 4 times to about 12 times the amount required to neutralize the acidic precursor, more preferably from about 6 times to about 12 times.

In the process of the present invention, the only water actually present in the material when it goes through the process is the small amount of water present in the raw material and the water produced by the neutralization of the acidic precursor of the anionic surfactant. The maximum moisture content in the material being processed is preferably about 10%, more preferably about 7%, still more preferably about 5%, most preferably about 3%, throughout the process. Detergent agglomerates produced by this process may be somewhat hygroscopic and acquire moisture from the atmosphere.

Detergent agglomerates obtained from the process of the present invention generally have an average particle size of from about 200 microns to about 800 microns, more preferably from about 300 microns to about 700 microns, even more preferably from about 400 microns to about 600 microns.

An advantage of the method of the present invention is that the use of glidants such as silica, clay, diatomaceous earth, aluminosilicates (eg zeolites), perlite and calcite can be substantially reduced or eliminated. Method steps

The present invention can be carried out in continuous or batch mode. Continuous processing is preferred. The process, carried out in a continuous manner, is described as follows:

The first step of the process is preferably carried out in a high speed, high shear mixer. Mixers suitable for this step include, for example, the Loedige ^CB® , Shugi ^Granulator® , and Drais K- ^TTP® . A preferred mixer for the first step is the Loedige ^CB® . Generally, high speed mixers have a substantially cylindrical mixing chamber with a diameter of about 0.3 m to about 1 m and a length of about 1 m to about 3.5 m. A preferred mixer for the first step has a central shaft to which the mixer blades are attached, preferably the central shaft rotates at a speed of from about 300 rpm to about 1800 rpm, more preferably from about 350 rpm to about 1250 rpm, still more preferably from about 400 rpm to about 1000 rpm, for relatively Larger mixers generally have lower speeds. The high-speed mixer is preferably water-jacketed, and cooling water is passed through the jacket of the mixer to remove the heat generated by the neutralization reaction.

For the first step of the process, the various basic raw materials (i.e., surfactant or surfactant acid precursor, carbonate, and phosphate (if used)) are generally fed into the cylinder near one end of the mixing chamber. to the high-speed mixer and intimately mix as it passes through the mixing chamber, while the mixture is discharged from the other end near the cylindrical mixing chamber. Generally, the average throughput rate is from about 0.2 kg/sec to about 17 kg/sec, especially from about 2 kg/sec to about 13 kg/sec. Higher throughput rates can be obtained with larger mixers. The average residence time of the raw materials in the first step mixer is preferably from about 2 seconds to about 30 seconds, more preferably from about 5 seconds to about 20 seconds, still more preferably from about 10 seconds to about 15 seconds.

When using acidic precursors of anionic surfactants, most of the acid is neutralized by carbonate in the first step of the process. Preferably substantially all of the neutralization occurs in the first step. However, the neutralization reaction can be completed after the mixture is discharged from the first-stage mixer. The acid is essentially completely neutralized during this process. Cooling water, preferably at a temperature of from about 5°C to about 25°C, is fed into the water jacket of the high speed mixer. The temperature of the mixture exiting the high speed mixer is generally from about 35°C to about 70°C, preferably from about 45°C to about 55°C.

The material discharged from the mixer of the first step is generally immediately sent to the mixer of the second step. The average residence time of the materials between the two mixers is preferably less than about 5 minutes, more preferably less than about 1 minute.

The second step of the process of the invention is preferably carried out in a medium speed mixer. Mixers suitable for this step include plowshare mixers such as Loedige ^KM® and Drais ^KT® . The Loedige ^KM® is the preferred mixer for use in the second step of the process of the present invention. Generally, moderate speed mixers have a substantially cylindrical mixing chamber with a diameter of about 0.6 m to about 2 m and a length of about 2 m to about 5 m. Preferred mixers have a central shaft to which the mixer blades are attached, preferably the central shaft rotates at a speed of from about 40 rpm to about 160 rpm, more preferably from about 45 rpm to about 140 rpm, still more preferably from about 50 rpm to about 100 rpm, typically for larger mixers The speed is lower. The medium speed mixer is preferably water jacketed, and cooling water is passed through the mixer jacket to maintain the temperature of the product in the medium speed mixer at about its feed temperature.

For the second step of the method, the mixture of various raw materials discharged from the mixer of the first step is usually sent into the medium speed mixer at one end close to the cylindrical mixing chamber, mixed as it passes through the mixing chamber, and Discharge near the other end of the cylindrical mixing chamber. Generally, the throughput rate of the second step is the same as that of the first step. The average residence time of the raw materials in the second stage mixer is preferably from about 0.5 minute to about 10 minutes, more preferably from about 0.5 minute to about 5 minutes, still more preferably from about 1 minute to about 4 minutes.

The temperature of the mixture exiting the moderate speed mixer is generally from about 35°C to about 70°C, preferably from about 45°C to about 55°C.

The agglomerates produced by the process herein can be used "as is" for detergent purposes. However, various other materials normally included in detergent compositions may be included substantially in the agglomerates themselves or mixed with the agglomerates in one or more subsequent mixing steps. These materials include organic polymeric builders such as polycarboxylates (see U.S. Patent No. 4,144,226 Diehl), phosphonic acid builders such as disclosed in U.S. Patent Nos. Alkali metal silicates, zeolite builders, bleaches, bleach activators, soil suspending agents, enzymes, perfumes, chelating agents and other surfactants such as alkyl polyethoxylates, ethoxylated Fatty amines, etc.

All percentages and ratios in this patent document are "by weight" unless otherwise indicated. All patents and patent applications identified herein are hereby incorporated by reference.

The invention will be illustrated by the following examples, which should not be considered to limit the invention in any way.

Example I

In this example, the following agglomerated compositions were prepared. A B Sodium alkylbenzene sulfonate 27.5% ^* 27.5% ^* Sodium carbonate 40.0 ^** 32.0 ^*** Tripolyphosphate 21.9 19.6 sodium sulfate 0.6 0.7 Zeolite 7.2 15.2 moisture 1.9 4.7 other substances to 100 to 100

^* 26.5% is unneutralized alkylbenzene sulfonic acid.

^** Neutralizes the first 44% of alkylbenzene sulfonic acids.

^*** Neutralizes the first 36% of alkylbenzene sulfonic acids.

Composition A was prepared according to the process of the present invention using an acidic precursor of an alkylbenzene sulfonate surfactant. A Loedige CB mixer was used in step 1 and a Loedige KM mixer was used in step 2. All raw materials (except zeolite) were added in step 1 and 20% of the zeolite (ie 1.44 parts by weight) was added in step 2. The "obtained" 97% of all sodium carbonate having a particle size of less than about 200 microns and a median particle size of 50 microns was ground and sized to meet the specification of 97% less than 40 microns and a median particle size of 10 microns. The tripolyphosphate had a "resulting" 97% particle size of less than 200 microns and a median particle size of 50 microns. The tripolyphosphate was not ground and size classified before use. Therefore, 44 parts by weight of carbonate, 67% of the total amount of phosphate and carbonate used to prepare the composition, was pretreated to meet the particle size specifications required by the present invention.

Composition B was prepared in the same manner as Composition A, except that both carbonate and phosphate "result" particle sizes were used. Additionally, in composition B, 90% of the zeolite was added in step 1 and 10% of the zeolite was added in step 2 (ie 1.52 parts by weight).

Composition A has excellent free-flow properties, while composition B has poor free-flow properties.

Both compositions were subjected to the "arch test". The ability of an agglomerate product to arch under pressure can be used in this test to identify potential flow problems in transport facilities and storage warehouses. In this test the agglomerate product is pressed into the shape of a dome in a cylindrical container and the stickiness of the product is evaluated by measuring the force required to break the dome. The more adhesive the product, the greater the force required. For composition A a force of 1.5 kg is required and for composition B a force of 3-5 kg is required.

Claims (8)

1. be used for process for making detergent agglomerates, it may further comprise the steps:

(a) mixture of each component of preparing washing agent in mixing tank, described mixing tank have with the axis of 300rpm-1800rpm rotation and 2 seconds-30 seconds mean residence time, and described each component comprises:

(1) surfactant compounds of the acidic precursor that is selected from anion surfactant and anion surfactant of about 20%-about 35%;

(2) about 0%-'s about 65% is selected from polyphosphate, pyrophosphate salt and composition thereof

The particle phosphate builders;

(3) particle that is selected from yellow soda ash, salt of wormwood and composition thereof of about 6%-about 60%

Carbonate is wherein before using the acidity of anion surfactant in (a) (1)

During body, the amount of carbonate be enough to neutralize described surfactant acid amount at least

2 times; Wherein, component (2) and (3) total amount to satisfy 97% particle at least about 20% be the requirement of the granularity specification of 5-20 micron less than 50 microns and medium size, the temperature of the mixture of discharge be 35 ℃-70 ℃ and

(b) in moderate-speed mixers, the mixture of step (a) is carried out agglomeration to produce detergent agglomerate, described mixing tank has with the axis of 40rpm-160rpm rotation and 0.5 minute-10 minutes mean residence time, and the temperature of the mixture of discharge is 35 ℃-70 ℃.

2. the process of claim 1 wherein that the amount of component (a) (1) is about 20%-about 30%.

3. the process of claim 1 wherein that the amount of component (a) (2) is about 5%-about 65%.

4. the process of claim 1 wherein that component (a) (1) is the acidic precursor of anion surfactant, and the amount of component (a) (3) be in and about 4 times-Yue 12 times of the required amount of component (a) (1).

5. the method for claim 1, wherein component (a) (1) is the acidic precursor of anion surfactant, the amount of component (a) (1) is about 20%-about 30%, the amount of component (a) (2) is about 55% for about 15%-, and the amount of component (a) (3) be in and about 4 times-Yue 12 times of the required amount of component (a) (1).

6. each method among the claim 1-5, wherein component (a) (2) and (a) (3) total amount at least 40% to satisfy 97% particle be the requirement of the granularity specification of 5-20 micron less than 50 microns and medium size.

7. the method for claim 6, wherein component (a) (2) and (a) at least 70% requirement of satisfying the granularity specification of claim 6 of (3) total amount.

8. the method for claim 6, wherein 97% described particle is less than 40 microns.