EP0594924B1

EP0594924B1 - Process for the manufacture of a liquid detergent composition comprising a sulphiting agent and an enzyme system

Info

Publication number: EP0594924B1
Application number: EP19920870177
Authority: EP
Inventors: Alan David Blake; Paul Andrew Hardy; Jozef Philemona Raymond Geudens; Fabrice François Jean Questel
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1992-10-28
Filing date: 1992-10-28
Publication date: 1996-07-24
Anticipated expiration: 2012-10-28
Also published as: AU5351194A; EP0594924A1; JPH08502778A; DE69212486D1; CN1044131C; CN1086254A; DE69212486T2; WO1994010283A1

Description

Technical Field

The present invention relates to the manufacture of liquid detergent compositions which comprise a sulphiting agent and an enzyme system.

Background

EP-A-185528, published on 25th June 1986, describes enzymatic drain cleaning compositions comprising proteolytic enzyme, disulfide reducing agent and an alkali metal bisulfite.
GB-A-2021142, published on 28th November 1978, is concerned with stabilised liquid enzyme-containing detergent compositions. Proteolytic enzyme activity is stabilised by means of an antioxidant such as sodium metabisulfite. There is no suggestion that there may be a malodour problem, nor how any such problem could be solved.
Liquid detergents have been described extensively in the art. In applicants' European patent application 91870175, made available to the public as the priority document for WO9309215, published on 13th May 1993, liquid laundry detergents are described which comprise a sulphiting agent that stabilises the color characteristics of said compositions.
A new technical problem has occurred upon using sulphiting agents in liquid detergents in that important odors are generated as the sulphiting agent is incorporated in said detergents, so that said detergent's odor significantly deviates from its defined standard. The problem the present invention seeks to solve is to avoid odor deviations in liquid laundry detergents which comprise sulphiting agents.
In response to this technical problem, applicants have found that said odor deviation is generated by an interaction between the sulphiting agent and the enzyme which is also present in said detergent. Without wanting to be bound by theory, it is believed that the sulphiting agent reacts with impurities which are typically present in commercially available enzyme preparations.
Thus to avoid odor deviations in a liquid detergent comprising an enzyme system and a sulphiting agent, the present invention proposes to intimately mix said enzyme system and said sulphiting agent apart from the remainder of said detergent composition.
Liquid detergent compositions comprising sulphiting agents have been described in DE 3729474, EP 80 748, EP 80 223, EP 79641, BE 796 115 and US 3,741,901. None of these documents suggest that enzymes and sulphiting agents may generate odor if they are mixed together. Furthermore, J01256596 (abstract) addresses the control of enzyme-originating odors. In the context of this document, sulphites are used to diminish the odor of enzymes.

Summary of the Invention

The present invention includes a process for the manufacture of a liquid detergent composition comprising a sulphiting agent and an enzyme system, whereby said enzyme system and said sulphiting agent interact together so as to generate odors, characterized in that said process includes the steps of:

intimately mixing said enzyme system and at least a portion of said sulphiting agent separately from the remainder of said detergent composition so as to generate said odor outside the remainder of said detergent composition, and
leaving said sulphiting agent and said enzyme system to interact in such conditions and until said odor has disappeared or is substantially reduced, and
thereafter adding said intimate mixture of said sulphiting agent and said enzyme system to the remainder of said detergent composition.

Detailed Description of the Invention

The present invention concerns the manufacture of liquid detergent composition. Liquid detergent compositions manufactured according to the present invention comprise conventional detergency ingredients, an enzyme system and a sulphiting agent.
As used herein, conventional detergency ingredients include such ingredients as surfactants, builders, bleaches, solvents, soil release agents, color care ingredients, chelants, dyes, perfumes and the like. The detergent compositions herein may be aqueous or anhydrous, and can further be formulated as so-called concentrated liquid detergent compositions. The detergent compositions according to the present invention can be formulated in a variety of different embodiments, especially laundry detergents.
The compositions manufactured according to the present invention further comprise a sulphiting agent. As used herein, sulphiting agents are compounds capable of yielding sulfite ions in said liquid detergent compositions. Such sulphiting agents include sulphite, hydrogenosulphite or pyrosulphite salts, sulfur dioxide and sulfurous acid, or mixtures thereof. Preferred for use herein are alkali metal sulphites, pyrosulphite or hydrogenosulphite, particularly potassium sulphites. The compositions manufactured according to the present invention comprise from 0.01% to 1% by weight of said total composition of said sulphiting agent, preferably from 0.05% to 0.7%, most preferably from 0.1% to 0.5%. As used herein, the term sulphiting agents includes mixtures of sulphiting agents.
The compositions manufactured according to the present invention further comprise an enzyme system. Said enzyme system includes protease, amylase, cellulase and lipase. As used herein, the term enzyme system includes single enzymes and mixtures thereof. Most commercially available enzymes come as preparations which comprise pure enzyme and impurities. It is believed that said impurities interact with the sulphiting agents to generate odors. Accordingly, the term "enzyme" as used herein refers to the enzyme together with the impurities which come with it. The present invention is only applicable to those enzymes, or enzyme preparations, which generate odors as they are intimately mixed with a sulphiting agent as described hereinabove. Such enzymes include commercially available Termamyl ® and Maxamyl ®. Detergent compositions manufactured according to the present invention comprise from 0.1% to 10% by weight of said enzyme system, preferably from 0.2% to 5%, most preferably from 0.5% to 3%.
The process according to the present invention comprises at least three steps.
In the first of these three steps, said sulphiting agent and said enzyme system are intimately mixed together apart from the remainder of said liquid detergent composition. As a result, during this first step said odor is generated outside the remainder of the detergent composition as said sulphiting agent and said enzyme system are intimately mixed together. By "intimately mixed" it is to be understood that said sulphiting agent and said enzyme system are mixed so as to ensure complete interaction between both ingredients, thus complete generation of said odor. In the present invention, it is possible to mix said enzyme system with the totality of the sulphiting agent to be formulated in the detergent composition, or only a portion thereof. In any case, said enzyme system must be intimately mixed with at least a portion of said sulphiting agent, wherein said portion of sulphiting agent represents a quantity which is sufficient to ensure complete generation of said odor. In practice, it has been noted that a very small quantity of sulphiting agent (see description of premix hereinafter) is required to completely generate said odor.
In the second step of the process according to the present invention, said sulphiting agent and said enzyme system are left to interact in appropriate conditions and until said odor has disappeared or is substantially reduced. In practice it appears sufficient to gently mix both ingredients under adequate aeration.
In the third step of the process according to the present invention, said intimate mixture of said sulphiting agent and said enzyme system is added to the remainder of said liquid detergent composition. It is to be understood that said intimate mixture can also be added to a portion of the remainder of said liquid detergent composition, which in turn may be added to a further portion of said liquid detergent composition or the remainder thereof.
A preferred enzyme premix consists essentially of said enzyme or mixtures thereof and said sulphiting agent or mixtures thereof. By "subtantially", it is meant herein that said premix also comprises impurities which come with the enzyme raw material and which interact with said sulphiting agent. Said premix preferably comprises from 0.1% to 5% by weight of said premix of said sulphiting agent, preferably from 0.1% to 1% by weight, the remainder of said premix being constituted by the enzyme raw material.
The present invention is further illustrated by the following example.

Example

A liquid detergent composition is made which comprises the listed ingredients in the listed proportions (weight %):

Linear Alkyl Benzene sulphonate	19.00
Nonionic surfactant	12.00
Fatty acid	11.00
Citric acid	5.00
Termamyl ® (1)	0.14
Potassium sulphite	0.13
Borate	2.50
Calcium chloride	0.02
Soil release agent	0.45
Brightener	0.15
Chelant	1.00
Ethanol	1.00
Propanediol	11.00
Monoethanolamine	9.50
Potassium hydroxide	1.50
Sodium hydroxide	1.80
Minors and water	up to 100 %

(1) Termamyl® is a commercially available amylase.

A premix comprising a portion of the potassium sulphite and the Termamyl® is prepared by intimately mixing 99.8 g of Termamyl which comes as a liquid raw material) with 0.2 g of K₂SO₃ powder until the K₂SO₃ powder is dissolved into the liquid enzyme raw material. The odor is generated instantaneously. Said premix of Termamyl® and potassium sulphites is mixed gently in an open container. After 48 hours, the odor generated as both ingredients were contacted disappears.
0.15 g of said premix is then added to the total remainder of said detergent composition (which includes the remainder of potassium sulphite) by gently mixing both in a beaker at room temperature.
The liquid detergent composition described above was thus generated and exhibited no odor deviation. For comparison, the same detergent composition was manufactured where the enzyme preparation was added without having been premixed with the sulphiting agent. Under these conditions, a strong odor deviation was generated.

Claims

A process for the manufacture of a liquid detergent composition comprising a sulphiting agent and an enzyme system whereby said enzyme system and said sulphiting agent interact together so as to generate odors, characterised in that said process incudes the steps of:
- intimately mixing said enzyme system and at least a portion of said sulphiting agent separately from the remainder of the detergent composition so as to generate said odors outside the remainder of said detergent composition, and

- leaving said sulphiting agent and said enzyme system to interact until said odor has disappeared or is reduced, and

- thereafter adding said intimate mixture of said sulphiting agent and said enzyme system into the remainder of the detergent composition wherein the detergent composition comprises from 0.01% to 1% by weight of sulphiting agent.
A process according to claim 1 characterised in that said enzyme premix consists essentially of an enzyme or mixtures thereof and a sulphiting agent or mixtures thereof.
A process according to claim 2 which comprises from 0.1% to 5% by weight of said premix of said sulphiting agent.
A process according to any of claims 1 to 3 wherein said sulphiting agent is potassium sulphite.