Liang Lei, Wen Yu

Xi’an Kaimi Co., Ltd., China

With the improvement of people’s living standard, more and more importance is attached to home environment and hygiene.[1]Kitchen is a very important part of modern household environment.However, nasty greasy stains are very easy to adhere to the utensils, range hood, ventilating fan, fuel gas stove,floor and walls in the kitchen, which not only turns the kitchen into a less neat and beautiful environment , but also makes it easy to breed bacteria and produce harmful odors to human health. People also put forward higher requirements for kitchen cleaning, but regular cleaners cannot remove the greasy stains effectively. Therefore,how to remove these greasy stains effectively has become the focus of study in the daily chemical industry.[2]

Formation and characteristics of kitchen greasy stains

The Chinese cooking methods and traditional living habits and factors alike cause heavy oil fumes in the kitchen and heavy greasy stain residues on the surfaces of utensils and peripheral items, which is ditficult to be cleaned In the process of cooking, the glyceryl oleate and the unsaturated fats in edible oil will form “paintlike” polymer[3]with strong adhesion and tenacity through oxidation, polymerization reactions at high temperatures for a long time. Some edible oil is attached to solid surfaces after gasification and condensation or even carbonization, forming the film-type dirt with strong strength and toughness.[4-6]In addition, tiny dusts and fine particles floating in the living environment would adhere to and deposit on the oil crust, increasing the difficulty of removal.

Main factors influencing the performance of kitchen cleaner formulas

Changes in home lifestyle

According to statistics, compared with the 1960s,the average time people spend in household cleaning is halved. In the early 20th century, few women worked outside; but now, the number of families in which both husband and wife have their respective jobs and that of single-person families will continue to rise, most women still have their own careers even after giving birth. Such families shorten their household time greatly. As a result,the cycle of kitchen cleaning becomes longer and the cleaning time is greatly reduced.

Changes in the materials of kitchen utensils

Currently, a variety of surface materials and coatings are used for kitchen utensils, such as stainless steel, toughened glass, porcelain, aluminum alloy, teflon-coated cold-rolled steel, paint and PVC, etc. These materials feature many advantages, including unique properties, bright colors, good appearances, easy-to-clean and so on, therefore they are favored by many consumers. However, due to widely-varied performance, these different materials also put forward more requirements for the performance of cleaners and bring a series of problems to the design and development of kitchen cleaners.

Characteristics of kitchen greasy dirt

Because of the eating habits of Chinese people,the main ways of cooking include: boiling, stir-frying,pan-frying and deep-frying. Due to high cooking temperatures, heavy fumes are generated during cooking.Greasy dirt is easy to become heavy greasy dirt through polymerization and oxidation reactions, increasing the difficulty of removal.

Changes in philosophy of life

With the improvement of living standards, people are not only very concerned about their health and hygiene,but also increase gradually their awareness of public environment protection; therefore they put forward higher requirements on the performance and efficacy of cleaning products.

Current situation of kitchen greasy dirt cleaners in China

In recent years, as the market competition intensifies, many manufacturers adjust the ingredients of their formulas to cater for consumers’ one-sided pursuit of product effect. They adopt the formula with higher proportion of solvent or alkaline additive and develop “powerful and strong” products in which the proportion of solvent is increased from the original 3%-8% to 8%-15% and even higher, a larger proportion of alkaline additive is added and moreover, organic alkali is replaced by inorganic alkali whose alkalinity is stronger. Although the formula effect is improved obviously, their harmfulness to the environment and human body is also increased. In addition, in order to avoid the drawbacks of product formulas,manufacturers introduce the products whose formulas are claimed to include natural ingredients (such as sweet orange oil) and put them on the market to reduce people’s awareness of the harmfulness of the formula.Subsequently, it whips up an “orange storm” on the greasy dirt cleaner market.[7]

Currently, there are mainly 3 types of heavy kitchen greasy stain cleaners: (1) strong-alkaline cleaners. This type of cleaners has a strong ability to remove heavy greasy stains by making use of the saponification reaction between strong alkali and the greases and acids in greasy dirt. Their advantages include low prices and readily available raw materials. But in the process of use, they cause corrosion to utensil surfaces and have strong irritation to human skin. (2) solvent-type cleaners.This type of cleaners dissolves and removes greasy dirt with organic solvent by making use of the principle of similarity and intermiscibility. The formula has a strong grease removal effect. But generally speaking, organic solvents have many shortcomings, as they are flammable and explosive, highly toxic to human bodies and easy to cause environmental pollution, etc. Meanwhile, the product cost is increased, due to the higher prices.(3) surfactant-type cleaners. This type of cleaners achieves synergy effect by combining a variety of surfactants and adding cleaning additives. Greasy dirt is emulsified,stripped off and dispersed in the cleaning solution through the process of wetting, infiltration, stripping,emulsification, dispersion and solubilization, etc. In the end, the greasy dirt is removed and cleared. This type of cleaners is easy to use, safe non-corrosive to the materials,featuring a relatively low cost of use. However, its ability to remove old and viscous greasy stains is poor.

Requirements for kitchen cleaners

From the perspective of most housewives, cleaning is rime-consuming and labor-intensive. It is not so fast and convenient. Only a handful of housewives really like and enjoy cleaning because most people have limited time, and they would rather do something else instead of cleaning.Housewives have “high quality” requirement for cleaning.They require not only a quick cleaning effect, but also demand green products with richer efficacies. Consumers always want to get best-performance products. According to the insiders, consumers will prefer multi-functional products, because they not only provide convenience for them, but also save more money .[8]

The basic functions of the cleaners are not enough to satisfy people’s requirements for kitchen cleaners nowadays. In addition to a high ability to remove greasy dirt, the product should also feature the following efficacies: they are nontoxic and safe to use and will not do harm to human and the environment; they have good rust inhibition and produce no corrosion to the surface of a cleaned object; there is no trace on the surface after the object is cleaned and dried; they have a pleasant fragrance in the process of use and after use; they have a strong bacteriostatic or sterilization effect; they are resistant to the redeposition of greasy stains and easier to clean next time.

Development trend of kitchen cleaners in the future

Because these 3 types of kitchen cleaners (namely strong-alkaline, solvent-type and surfactant-type cleaners) have their respective advantages and disadvantages, people began to pay attention to and analyze the respective characteristics of these 3 types of cleaners and developed a new type of kitchen cleaners combining all the advantages of the 3 types. A waterbased cleaner was developed at home and abroad in recent years. Its main ingredient is surfactant. This type of cleaner is characterized by good cleaning performance, strong dirt removal capbility, safety in use, uninflammability, nontoxicity, less environmental pollution, energy saving and low cleaning cost, etc.Furthermore, with the continuous integration of the advantages by the developers, the products not only deliver high efficiency at room temperature and low temperature, but also have some additional functions,such as rust resistance and protection and so on. Besides,more diversified product types, including powder-type and special type as well as the products applicable to automatic and mechanical cleaning and so on can be provided.

Environmental friendly and safety of raw materials.With the improvement of people’s living level and awareness of environmental protection, people begin to pay more and more attention to personal health and self-protection. The government also released the requirements on biodegradability for surfactants and the regulations limiting the use of phosphoruscontaining additives and volatile organic solvents.Nowadays, in order to better guide consumption and promote environmental protection, the EU has proposed that 19 types of products should obtain environmental protection label before sales and has moved gradually towards the compulsory execution of the regulations where various types of cleaners are concerned. China has launched the attestation of China Environmental Labeling. Only a few brands, such as“Kaimi”, “WhiteCat”, have passed the attestation. In January 2011, the Ministry of Environmental Protection and the General Administration of Customs of China announced jointly the implementation of import release permit and enterprise registration for imported nonylphenol products, and included this type of substances into the List of Toxic Chemicals Restricted to be Import into or Export from China.[9]This indicated that phenol surfactants would no longer be used in the Chinese civilian detergent market. The glycol ether series solvents, such as carbitol (diethylene glycol diethyl ether) and butyl carbitol (diethylene glycol monobutyl ether) and so on, which are commonly used in kitchen cleaners, are good at removing water-soluble and oilsoluble greasy stains, moreover, with a light odor, they are considered the organic solvent and cleaner with good performance. However, they have great toxicity and poor biodegradability.[10]Faced with these problems, it is required to continuously develop new multi-functional environmentally-friendly additives that have no harm to human and are able to meet the needs of future.

New kitchen cleaners.Recently, people’s requirements for kitchen cleaners are not fully met, and the performance of the existing products is far from satisfactory. The main problem is that the effect of the removal of heavy greasy stains is not well, and can’t meet the consumer's requiremeents. Some new kitchen cleaners have appeared at home and abroad in recent years. They can be mainly divided into the following types:

(1) Microemulsion kitchen cleaners

Microemulsion has a property of ultra-low interfacial tension, which can reduce the adhesion of greasy stains to object surfaces and make it easier for solution to embed into greasy stains. This not only improves the alkaline's ability to saponify the greasy dirt, but also increase the organic solvent's ability to dissolve greasy dirt. Consequently, greasy dirt can be removerd more easily. The cleaning effect and performance of cleaners are improved. Therefore, the kitchen cleaning becomes easier and faster accordingly.

(2) Spray foam kitchen cleaners

The spray foam adhesion technology is used for spray foam kitchen cleaner. This technology prolongs the action time of the cleaner on greasy stain surfaces, guarantees effectively the time of embedding of the cleaner into greasy stains, greatly increases the area of action between the solution and greasy stains, reduces the decrease of effectiveness caused by loss of cleaner from greasy stain surfaces during use, reduces the volume of solution for use, and improves the grease removal effect. This type of cleaner reduces the use cost and brings convenience to consumers.

(3) Kitchen cleaning gel

Kitchen cleaning gel is more suitable for cleaning vertical surfaces. The solution has a long time to adhere to surfaces and interacts fully with the greasy stains, so the grease removal effect can be improved and the loss of solvent can be reduced. The liquid has relatively high viscosity, the volatility of organic solvent in the solution decreases significantly,reducing the harm to human. Therefore, this kind of cleaner is safer to use.

(4) Enzyme-based kitchen cleaners

As a kind of biocatalyst, enzyme has high efficiency and specificity to remove greasy stains. Enzyme is added to make the formula milder and safer, which improves the grease removal effect greatly. Enzyme-based cleaner is not harmful and corrosive for the environment, as well as human health. Therefore, this type of product can meet people’s requirements of safety and environmental protection. The function of enzyme in energy saving and environmental protection makes enzyme a broader development prospect in the cleaning industry.

Conclusion

The traditional Chinese cooking ways make it easy to form kitchen greasy dirt with high viscosity. It is hard to achieve ideal removal effect with general cleaners. The main demands of consumers for kitchen cleaners are efficiency and convenience. In recent years, as the living environment has been polluted gradually, consumers begin to pay more and more attention to the source of the raw materials of the products, focus on security and the environment impact, etc. Consumers prefer green,natural, healthy, mild, safe, environmental-friendly,condensed, energy-saving, multi-functional and multipurpose liquid cleaners. The fierce competition of daily chemical products makes all enterprises try their best to meet consumers’ requirements. On the one hand,they make constant efforts to refine and customize the products. At the same time, they combine the functions of the products to meet the consumers’ requirements.Understanding the current needs of the consumers will play a key role in decision of the main selling points of the products. Exploring the consumers’ expectation and development trend of the products will make it possible to guide the choice of the consumers. Market-oriented research and development should become more targeted and effective so as to better meet the needs of consumers and gain more benefits for enterprise.

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