Agglomerated granules for the delayed release of antifoaming agents in laundering systems

Claims

What is claimed is:

1. A delayed release antifoam laundry additive consisting essentially of one or more conventional silicon based antifoam agents held on a carrier comprising water soluble modified cellulose, wherein said antifoam agent is contained in said laundry additive in an amount of from about 10 to 45' wt. % based on the weight of said antifoam agent and said carrier taken together, said delayed release antifoam laundry additive being formed by the process comprising the steps of:

(i) first uniformly loading said antifoam agent on said carrier;

(ii) then mixing said carrier in the presence of an amount of a solvent for said carrier sufficient to cause agglomeration of said carrier: and

(iii) then driving the solvent from the carrier.

2. A delayed release antifoam laundry additive as claimed in claim 1, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

3. A delayed release antifoam laundry additive as claimed in claim 1, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.5 to 1.0% per 100 parts by weight of said conventional dry laundry detergent.

4. A delayed release antifoam laundry additive as claimed in claim 1, wherein said antifoam agent is a conventional silicone-filled polydimethyl siloxane antifoam agent and is contained in said laundry additive in an amount of from about 10 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together, said carrier being selected from the group consisting of substituted alkyl ethers of cellulose, unsubstituted alkyl ethers of cellulose and salts of carboxyalkyl cellulose.

5. A delayed release antifoam laundry additive as claimed in claim 4, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

6. A delayed release antifoam laundry additive, as claimed in claim 4, wherein said additive has a granular form with particles ranging from 0.5 to 2.0 mm in diameter.

7. A delayed release antifoam laundry additive as claimed in claim 4, wherein said antifoam agent is further defined as being contained in said laundry additive in an amount of from 20 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together.

8. A delayed release antifoam laundry additive as claimed in claim 7, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

9. A delayed release antifoam laundry additive, as claimed in claim 7, wherein said additive has a granular form with particles ranging from 0.5 to 2.0 mm in diameter.

10. A delayed release antifoam laundry additive as claimed in claim 7, wherein said antifoam agent is further defined as being contained in said laundry additive in an amount of from 20 to 40 wt. % based on the weight of said antifoam agent and said carrier taken together.

11. A delayed release antifoam laundry additive as claimed in claim 7, wherein said carrier is further defined in that the alkyl groups of said substituted and unsubstituted alkyl ethers of cellulose and carboxyalkyl cellulose have from 1 to 6 carbons, and said salts of carboxyalkyl cellulose are alkaline metal salts.

12. A delayed release antifoam laundry additive as claimed in claim 11, wherein said carrier is selected from the group consisting of methyl ethers of cellulose, ethyl ethers of cellulose, hydroxypropyl ethers of cellulose and sodium carboxymethyl cellulose.

13. An agglomerated delayed release antifoam laundry additive, consisting essentially of one or more conventional silicon based antifoam agents loaded on a carrier comprising water soluble modified cellulose, wherein said antifoam agent is contained in said laundry additive in an amount of from about 10 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together, said carrier being agglomerated with a solvent for the carrier subsequent to loading of said antifoam agent onto said carrier.

14. An agglomerated delayed release antifoam laundry additive, as claimed in claim 13, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

15. A delayed release antifoam laundry additive as claimed in claim 13, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.5 to 1.0% per 100 parts by weight of said conventional dry laundry detergent.

16. An agglomerated delayed release antifoam laundry additive, as claimed in claim 13, wherein said antifoam agent is a conventional silica-filled polydimethyl siloxane antifoam agent and is contained in said laundry additive in an amount of from about 10 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together, said carrier being selected from the group consisting of substituted alkyl ethers of cellulose, unsubstituted alkyl ethers of cellulose and salts of carboxyalkyl cellulose.

17. An agglomerated delayed release antifoam laundry additive, as claimed in claim 16, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

18. A delayed release antifoam laundry additive, as claimed in claim 16, wherein said additive has a granular form with particles ranging from 0.5 to 2.0 mm in diameter.

19. An agglomerated delayed release antifoam laundry additive, as claimed in claim 16, wherein said antifoam agent is further defined as being contained in said laundry additive in an amount of from 20 to 40 wt. % based on the weight of said antifoam agent and said carrier taken together.

20. An agglomerated delayed release antifoam laundry additive, as claimed in claim 16, wherein said antifoam agent is further defined as being contained in said laundry additive in an amount of from 20 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together.

21. An agglomerated delayed release antifoam laundry additive, as claimed in claim 20, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

22. A delayed release antifoam laundry additive, as claimed in claim 20, wherein said additive has a granular form with particles ranging from 0.5 to 2.0 mm in diameter.

23. A delayed release antifoam laundry additive as claimed in claim 22, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

24. An agglomerated delayed release antifoam laundry additive, as claimed in claim 20, wherein said carrier is further defined in that the alkyl groups of said substituted and unsubstituted alkyl ethers of cellulose and carboxyalkyl cellulose have from 1 to 6 carbons, and said salts of carboxyalkyl cellulose are alkaline metal salts.

25. An agglomerated delayed release antifoam laundry additive, as claimed in claim 24, wherein said carrier is selected from the group consisting of methyl ethers of cellulose, ethyl ethers of cellulose, hydroxypropyl ethers of cellulose and sodium carboxymethyl cellulose.

26. A delayed release antifoam laundry additive consisting of one or more conventional silicon based antifoam agents held on a carrier comprising water soluble modified cellulose, wherein said antifoam agent is contained in said laundry additive in an amount of from about 10 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together, said delayed release antifoam laundry additive being formed by the process comprising the steps of:

(i) first uniformly loading said antifoam agent on said carrier;

(ii) then mixing said carrier in the presence of an amount of a solvent for said carrier sufficient to cause agglomeration of said carrier; and

(iii) then driving the solvent from the carrier.

27. A delayed release antifoam laundry additive as claimed in claim 26, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.5 to 1.0% per 100 parts by weight of said conventional dry laundry detergent.

28. A delayed release antifoam laundry additive as claimed in claim 26, wherein said antifoam agent is a conventional silicone-filled polydimethyl siloxane antifoam agent and is contained in said laundry additive in an amount of from about 10 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together, said carrier being selected from the group consisting of substituted alkyl ethers of cellulose, unsubstituted alkyl ethers of cellulose and salts of carboxyalkyl cellulose.

29. A delayed release antifoam laundry additive, as claimed in claim 28, wherein said additive has a granular form with particles ranging from 0.5 to 2.0 mm in diameter.

30. A delayed release antifoam laundry additive as claimed in claim 28, wherein said antifoam agent is further defined as being contained in said laundry additive in an amount of from 20 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together.

31. A delayed release antifoam laundry additive, as claimed in claim 30, wherein said additive has a granular form with particles ranging from 0.5 to 2.0 mm in diameter.

32. A delayed release antifoam laundry additive as claimed in claim 30, wherein said antifoam agent is further defined as being contained in said laundry additive in an amount of from 20 to 40 wt. % based on the weight of said antifoam agent and said carrier taken together.

33. A delayed release antifoam laundry additive as claimed in claim 32, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

34. A delayed release antifoam laundry additive as claimed in claim 30, wherein said carrier is further defined in that the alkyl groups of said substituted and unsubstituted alkyl ethers of cellulose and carboxyalkyl cellulose have from 1 to 6 carbons, and said salts of carboxyalkyl cellulose are alkaline metal salts.

35. A delayed release antifoam laundry additive as claimed in claim 34, wherein said carrier is selected from the group consisting of methyl ethers of cellulose, ethyl ethers of cellulose, hydroxypropyl ethers of cellulose and sodium carboxymethyl cellulose.

36. A delayed release antifoam laundry additive consisting of one or more conventional silicon based antifoam agents held on a carrier comprising water soluble modified cellulose, wherein said antifoam agent is contained in said laundry additive in an amount of from about 10 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together, said delayed release antifoam laundry additive being formed by the process comprising the steps of:

(i) first uniformly loading said antifoam agent on said carrier;

(ii) then mixing said carrier in the presence of an amount of a solvent for said carrier sufficient to cause agglomeration of said carrier; and

(iii) then driving the solvent from the carrier; and said delayed release antifoam laundry additive is in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

37. A delayed release antifoam laundry additive consisting of one or more conventional silicon based antifoam agents held on a carrier comprising water soluble modified cellulose, wherein said antifoam agent is contained in said laundry additive in an amount of from about 10 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together, said delayed release antifoam laundry additive being formed by the process comprising the steps of:

(i) first uniformly loading said antifoam agent on said carrier;

(ii) then mixing said carrier in the presence of an amount of a solvent for said carrier sufficient to cause agglomeration of said carrier; and

(iii) then driving the solvent from the carrier; and said delayed release antifoam laundry additive is in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

38. A delayed release antifoam laundry additive consisting of one or more conventional silicon based antifoam agents held on a carrier comprising water soluble modified cellulose, wherein said antifoam agent is contained in said laundry additive in an amount of from about 10 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together, said delayed release antifoam laundry additive being formed by the process comprising the steps of:

(i) first uniformly loading said antifoam agent on said carrier;

(ii) then mixing said carrier in the presence of an amount of a solvent for said carrier sufficient to cause agglomeration of said carrier; and

(iii) then driving the solvent from the carrier; and said delayed release antifoam laundry additive is in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

39. An agglomerated delayed release antifoam laundry additive, consisting of one or more conventional silicon based antifoam agents loaded on a carrier comprising water soluble modified cellulose, said carrier being agglomerated with a solvent for the carrier subsequent to loading of said antifoam agent onto said carrier, wherein said antifoam agent is contained in said laundry additive in an amount of from about 10 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

40. An agglomerated delayed release antifoam laundry additive, consisting of one or more conventional silicon based antifoam agents loaded on a carrier comprising water soluble modified cellulose, said carrier being agglomerated with a solvent for the carrier subsequent to loading of said antifoam agent onto said carrier, wherein said antifoam agent is contained in said laundry additive in an amount of from about 10 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together.

41. A delayed release antifoam laundry additive as claimed in claim 40, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.5 to 1.0% per 100 parts by weight of said conventional dry laundry detergent.

42. An agglomerated delayed release antifoam laundry additive, as claimed in claim 40, wherein said antifoam agent is a conventional silica-filled polydimethyl siloxane antifoam agent and is contained in said laundry additive in an amount of from about 10 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together, said carrier being selected from the group consisting of substituted alkyl ethers of cellulose, unsubstituted alkyl ethers of cellulose and salts of carboxyalkyl cellulose.

43. A delayed release antifoam laundry additive, as claimed in claim 42, wherein said additive has a granular form with particles ranging from 0.5 to 2.0 mm in diameter.

44. An agglomerated delayed release antifoam laundry additive, as claimed in claim 42, wherein said antifoam agent is further defined as being contained in said laundry additive in an amount of from 20 to 40 wt. % based on the weight of said antifoam agent and said carrier taken together.

45. An agglomerated delayed release antifoam laundry additive, as claimed in claim 42, wherein said carrier is selected from the group consisting of substituted alkyl ethers of cellulose, unsubstituted alkyl ethers of cellulose and salts of carboxyalkyl cellulose.

46. An agglomerated delayed release antifoam laundry additive, as claimed in claim 45, in admixture with a conventional dry laundry detergent, wherein said antifoam agent is present in an amount of from 0.1 to 2.0% per 100 parts by weight of said conventional dry laundry detergent.

47. An agglomerated delayed release antifoam laundry additive, as claimed in claim 42, wherein said antifoam agent is further defined as being contained in said laundry additive in an amount of from 20 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together.

48. A delayed release antifoam laundry additive, as claimed in claim 47, wherein said additive has a granular form with particles ranging from 0.5 to 2.0 mm in diameter.

49. An agglomerated delayed release antifoam laundry additive, as claimed in claim 47, wherein said carrier is further defined in that the alkyl groups of said substituted and unsubstituted alkyl ethers of cellulose and carboxyalkyl cellulose have from 1 to 6 carbons, and said salts of carboxyalkyl cellulose are alkaline metal salts.

50. An agglomerated delayed release antifoam laundry additive, as claimed in claim 49, wherein said carrier is selected from the group consisting of methyl ethers of cellulose, ethyl ethers of cellulose, hydroxypropyl ethers of cellulose and sodium carboxymethyl cellulose.

51. A method of forming agglomerated granules for the delayed release of antifoam agent in water which comprises loading one or more conventional silicon based antifoam agents on a carrier of water soluble modified cellulose, wherein said antifoam agent is contained in said laundry additive in an amount of from about 10 to 45 wt. % based on the weight of said antifoam agent and said carrier taken together then mixing the carrier loaded with antifoam agent in the presence of a solvent for the carrier in an amount sufficient to agglomerate said carrier.

52. A method as claimed in claim 51, wherein said method further comprises driving said solvent for the carrier from said carrier subsequent to agglomerating said carrier.

BACKGROUND OF THE INVENTION

The invention relates to laundry additive and detergent compositions having components which are designed for time delayed release in laundering systems. More specifically, the invention is a laundry additive comprising an antifoam agent held by a carrier, wherein the carrier is soluble in laundry water and releases the antifoam agent into the laundering system, after a period of delay. The invention also contemplates the mixture of the delayed release additive of the invention and a conventional dry powdered or granular laundry detergent.

The invention developed from a need to provide a laundry detergent with an additive for controlling detergent foam or suds formation. In mechanical laundering operations it is often considered desirable to reduce the amount of detergent foam in the laundry water for several reasons. By reducing foaming and suds, the surfactant which would otherwise be suspended in the foam is returned to the laundry water where its cleaning action is most effective. Reducing the amount of foam in the laundry water also aids in rinsing the detergent from the laundered articles. Detergent is more easily and throughly removed from the laundered articles when the detergent is in solution, rather than in the form of foam. Also, controlling the amount of detergent foam reduces the possibility of foam overflowing the wash machine and flooding the adjacent laundry area.

Adding an antifoaming agent directly to the wash at the beginning of the laundry cycle would be immediately effective in suppressing the formation of detergent foam. Suppression of foam from the onset of the wash cycle is not generally viewed as a desirable condition. A person doing the wash may wrongly conclude that the lack of foam from the time of adding the detergent indicates that an insufficient amount of detergent has been added to the wash, or that the detergent lacks efficacy. It is therefore preferred to have a laundry detergent which has an initial foaming stage to indicate the detergent is working and is present in an adequate amount, but which also permits the foam to dissipate later in the wash cycle so that the above mentioned drawbacks of detergent foam can be avoided.

Detergent composition containing antifoaming agents held on carriers are known in the art. U.S. Pat. No. 4,451,387 discloses a granular detergent composition with a suds control agent held on a carrier. The suds control component comprises carrier having a gelatinized starch core with a mixture of silicone oil and hydrophobic silica adsorbed thereon. In this patent it is strongly preferred that the suds control agent be coated with a layer of wax to improve the storage characteristics of the suds control agent.

European Patent Application No. 0,206,522 discloses a particulate antifoam ingredient suitable for incorporation into a detergent powder composition. High and low temperature sensitive antifoaming agents are supported on a core comprised of gelatinized starch, sodium perborate monohydrate, zeolite cation exchanger, water soluble salts such as sodium tripolyphosphate and sodium sulphate in admixture with hydrophobic silica and/or paraffin wax, or hydrophobic silica and/or paraffin wax with gelatinized starch.

Attempts were made by the inventor to prepare antifoam laundry additives, as disclosed in U.S. Pat. No. 4,451,387 and European Patent Application No. 0,206,522 using gelatinized starch as a carrier, but without including a wax or material other than a carrier and antifoam agent. It was found that without wax the gelatinized starch carrier and antifoam combined to make a wet, sticky mass that was unsuitable for storage or practical use as intended with the invention.

A detergent composition containing an antifoaming agent which becomes active during the rinse cycle is disclosed in U.S. Pat. No. 4,637,890. The detergent composition contains a plurality of suds control prills comprising fatty acid soap, quaternary ammonium salt, and a silicone fluid suds suppressor. It is theorized in the patent that the prills dissolve in the relatively high pH (e.g. from about 9 to about 10.5 pH) wash water, but that the antifoam components of the prills do not become active until exposed to lower pH solutions, that is, the water of the rinse cycle. When the high pH wash water is removed from the wash machine, components of the prills are physically carried over with articles being laundered into the rinse water. The rinse water naturally has a lower detergent content than the wash water and consequently it has a lower pH which allows the prill components to dissociate, initiating antifoaming activity.

Japanese Patent Application No. 73,126,930 also discloses a coated laundering aid which remains intact during the high pH alkaline washing cycle but is soluble in rinse water.

A publication of The Dow Chemical Company entitled Formulating for Controlled Release with Methocel Cellulose Ethers discloses the use of modified cellulose ethers in medicine tablets to control and slow the release of a pharmacologically active agent over a period of time, in order to prevent the sudden "dumping" of a medication into a patient's system.

SUMMARY OF THE INVENTION

The present invention relates to a delayed release laundry additive comprising one or more antifoam agents adsorbed on a powdered water soluble carrier selected from one or more modified cellulose carriers, which is subsequently agglomerated into granular form by mixing in the presence of a solvent for the carrier. The invention further comprises as optional, a conventional dry powdered or granular laundry detergent in admixture with granules of the delayed release antifoam laundry additive. The method by which delayed release antifoam laundry additives of the invention are prepared is claimed.

DETAILED DESCRIPTION OF THE INVENTION

The invention comprises one or more antifoam agents held by a water soluble carrier for time delayed release into the laundry water of a laundering system. Optionally, the invention further includes a conventional detergent throughout which is distributed agglomerated granules of the carrier holding the agent.

Suitable antifoaming agents can be selected from the group consisting of silicon based antifoams, particularly conventional inorganic-filled polydimethyl siloxane antifoam agents, especially silica -filled polydimethyl siloxane antifoam agents as disclosed in U.S. Pat. Nos. 4,639,489 and 3,455,839, incorporated herein by reference. These and other suitable antifoam agents are commercially available under the tradenames of Silcolapse 431 and Silicone EP 6508 from ICI United States Inc., Wilmington, Delaware, Rhodosil 454 from Rhone-Poulenc Chemical Co., Monmouth Junction, New Jersey and Silkonol AK 100 commerically available from Wacker-Chemie G.m.b.H., Munich, Federal Republic of Germany.

The above list is not intended to be a comprehensive listing of all antifoam agents which can be used in the invention. Rather it is intended to be illustrative of a broad range of materials which can be incorporated into the invention as antifoam agents. Other antifoam agents not listed above can be used in the invention as long as the agents are compatible with the carrier and perform in a laundering system in the desired controlled release fashion. It is of particular importance that they have an oily consistency and not be water soluble.

The carrier of the invention is a solid particulate structure of modified cellulose which holds a quantity of the desired laundering agent or agents. It is believed that the time release aspect of the invention is due to the antifoam agent being concentrated mainly in and around the center or interior portion of the carrier particle, due to the agglomeration process by which granular particles of the carrier are formed. The inventor theorizes that in the agglomeration step by which the granules of the invention are formed, the water or other solvent for the carrier actually drives the antifoam agent toward the center of the granule being formed. The exterior portion, or crust, of the granules are thereby left relatively free of antifoam agent.

The carrier is soluble in laundry water, but dissolves at a relatively slow rate due to the swelling of the surface of the particle in contact with the laundry water. Because the exterior portion of the granules is relatively free of antifoam agent, no antifoam activity is discernable until the exterior portion of the granule has been dissolved away, exposing the interior of the granule loaded with agent. Delayed release of the laundry agent is thereby effected.

By altering the size of the grains of the particulate carrier and the amount of agent held by the carrier, the approximate time of release of the laundering agent can be adjusted.

It is projected that under actual laundering conditions the antifoam agent will begin to be released from the carrier toward the end of the wash (agitation) cycle. The partially hydrated granules of additive will cling to the articles being laundered and continue dissolving in the subsequent rinse cycle, thereby providing crucial antifoam activity in the rinse water.

The water soluble carrier of the invention is a modified cellulose material, comprising one or more members selected from the group consisting of substituted alkyl ethers of cellulose, unsubstituted alkyl ethers of cellulose, and salts of carboxyalkyl cellulose. The preferred substituted alkyl ethers of cellulose have alkyl groups in the range of 1 to 6 carbons, and in particular, methyl ethers of cellulose and ethyl ethers of cellulose and those having mixed substituents, such as hydroxypropyl methyl cellulose are highly preferred. Unsubstituted alkyl ethers of cellulose include hydroxypropyl ethers of cellulose. The carrier also includes salts of carboxyalkyl cellulose, such as alkaline metal salts of carboxyalkyl cellulose, preferably, sodium carboxymethyl cellulose.

The controlled release laundering additives of the invention may be made by a batch process or in a continuous stream process. An example of the invention made according to the batch process is set forth in the following example:

EXAMPLE 1

115 g of methyl cellulose ether carrier (90 g Methocel A4M, manufactured by Dow Chemical Co., Midland, Michigan, and 25 g carboxymethyl cellulose ether) in the form of a finely divided powder was placed in the mixing container of a Hobart mixer. 75 g of an antifoaming agent, of the general type described in U.S. Pat. No. 3,455,839, comprising 77.4 parts by weight polydimethylsiloxane having a viscosity of approximately 1000 cStokes, 9.0 parts by weight silicone resin composed of (CH.sub.3).sub.3 SiO.sub.1/2 units and SiO.sub.2 units in which the ratio of the (CH.sub.3).sub.3 SiO.sub.1/2 units to the SiO.sub.2 units is within the range of from 0.6:1 to 1.2:1, and silica aerogel, was slowly added to the carrier by dripping, while the carrier was mixed, thereby evenly distributing the agent throughout the carrier. On completing the addition of the antifoaming agent to the carrier, the carrier retained its fluffy, loose-powdery appearance and texture.

Agglomeration of the powdery carrier to a granular form was carried out by slowly dripping deionized water onto the antifoam adsorbed carrier while mixing with the Hobart mixer was continued. As water contacted and hydrated the surface of the powdery carrier particles, the particles became slightly sticky and began to agglomerate or clump together forming granules. When the granules reached a desirable size, that is, in the range of from 0.5 to 2.0 mm in diameter, they were placed in a drying oven until the water from the agglomeration step was driven off.

It is theorized by the inventor that the water added in the agglomeration step is responsible for concentrating the laundering agent in and around the center of the carrier particles. It is believed that the water used in the agglomeration step drives the laundering agent toward the center of the granular particle and leaves the outer portion of the particle hydrated, but relatively agent-free, thereby giving the particle its time-release properties.

Other methods of distributing the laundering agent evenly throughout the carrier are within the scope of this invention. These methods include spraying of the agent onto the carrier while the carrier is being mixed and also adsorbing the agent on the carrier by means of a fluidized bed system wherein the agent would be sprayed or dripped into a column of powdered carrier suspended and agitated by gas.

When an antifoam agent having a high viscosity is used dripping or spraying of the agent onto the carrier and otherwise evenly distributing the agent throughout the carrier may be difficult or even impossible. However, this situation can be easily remedied by diluting the high viscosity antifoam agent with a solvent to obtain a more manageable consistency. Care must be taken in choosing the solvent so that it is selective for the antifoam agent and will not dissolve the carrier, thereby causing premature agglomeration. Agglomeration at the agent adsorption stage of the process is believed to hinder the uniform distribution of the laundry agent throughout the carrier.

Typically, the solvent for an agent will be a non-polar, aliphatic solvent. Methylene chloride (CH.sub.2 Cl.sub.2) or a paraffinic hydrocarbon solvent, such as Isopar E, commercially available from Exxon Co., U.S.A., Houston, Texas, can be used as solvents for the antifoaming agents of the invention.

Water is the preferred carrier solvent used in the agglomeration step. However, agglomeration of the carrier may alternatively be carried out using solvents other than water, suitable for the specific carrier, such as ethylene glycol ethylether, commercially available from Dow Chemical Co., Inc., Midland, Michigan, and sold under the trade name Dowanol EE, mixtures of glycerin and water, and mixtures of methylene chloride and lower alcohols, such as methanol, ethanol, isopropanol and normal propanol. The agglomeration and drying steps with nonaqueous solvents can be carried out in exactly the same manner as set forth in Example 1, although drying times when using solvents less volatile than water will naturally be longer.

The carriers of the invention can hold a wide weight range of antifoam agents and still remain effective. As a general rule, the weight proportion of agent to carrier will be determined primarily by the expense of the carrier and is not considered to be a critical technical aspect of this invention. However, it is preferred that the antifoam agent comprise from about 10 to 45 wt. % of the antifoam agent and carrier together. A more preferred weight range of the antifoam agent is from about 20 to 45 wt. % of the antifoam agent and carrier together. The most preferred weight range of the antifoam agent is from about 20 to 40 wt. % of the antifoam agent and carrier together. It is also possible to add amounts of dyes or coloring agents for the purpose of coloring the carrier. The dyes and coloring agents contemplated are those which would be those commonly known in the industry for coloring dry laundry detergents. The amount of dye or coloring agent incorporated in the invention is an amount sufficient to produce a color aesthetically pleasing to the formulator practicing the invention. Dyes and coloring agents can be added to the invention either during the antifoam agent loading step or during the agglomeration step.

When the antifoam additive is combined in admixture with a conventional dry laundry detergent the antifoam agent is required to be present in an amount in the range of from 0.1 to 2.0% antifoam agent per 100 parts by weight of dry laundry detergent. The preferred range of antifoam agent is from 0.5 to 1% antifoam agent per 100 parts by weight of dry laundry detergent.

Numerous examples of the invention were prepared according to the invention, the formulations of which are set forth in TABLE 1 below:

TABLE 1 __________________________________________________________________________ % Anti- Anti- Sample foam (gm) Carrier gm foam Solvent Remarks _______________________________________________________________________