Laundry gels can be divided into single-chamber and multi-cavity forms. Commercially available multi-cavity laundry gels have two, three, four, and five cavities, and different shapes are formed by adjusting the size of the cavities and the color of the material. With the development of multi-chamber packaging process, incompatible raw materials are separated by water-soluble film, such as solid-liquid gels with sodium percarbonate particles with concentrated liquid, which brings the function matching that is difficult to be realized by traditional laundry detergents, and truly realizes multi-functional laundry gels. This provides more space for the formulation of gel beads, adding materials with functions such as long-lasting fragrance, long-lasting anti-bacteria, softening, anti-static, color protection, color stringing and so on into different chambers, combining them into new products of laundry gel beads.
Packaging film for laundry gels
The mechanism of using laundry gel is to contact the polyvinyl alcohol (PVA) packaging film through water, so that it dissolves and releases the laundry detergent, and the water-soluble outer film is a key technical issue that has long affected the development of laundry gel. The barrier property of the membrane itself can effectively avoid the oxidation reaction between the material in the laundry gel and the oxygen in the air, and at the same time prevent the microorganisms in the environment from contaminating the material to deteriorate and reduce the volatility of the aroma.
Since PVA films are particularly sensitive to moisture, proper storage and use conditions are very important for laundry gels.PVA films are sensitive to bleach, which can affect the storage stability of laundry gels if the contents contain sodium hypochlorite. Polyvinyl Alcohol in detergents also has the added benefit of resisting the redeposition of dirt and is environmentally friendly and easily degradable. The polyvinyl alcohol solution produced after use of the laundry gel is broken down by bacteria isolated from the soil within 180d and eventually degraded to carbon dioxide and water.
The production process of laundry gel beads is roughly as follows: a layer of water-soluble film as the bottom film, through vacuuming into the appropriate mold, fit to the mold, into which the required amount of content, and then another layer of water-soluble film as the top film, in the bottom film and the top film sealing to do the heating or wetting process, and through the pressurized sealing process, so that the wrapped whole piece of laundry gel beads, and then cut into individual laundry Then cut it into single laundry gels.
Contents of Laundry Gel
The basic formulation of laundry gel beads generally consists of a small amount of water, surfactants, detergent additives, organic solvents, enzymes, bacteriostatic agents, flavors, colorants, etc., but also to examine the compatibility between PVA water-soluble film and the formulation of the material liquid. In the contents of the laundry gel, the water content of the formula is a very critical factor, the water content of the formula is required to control the following 10%, too much water will lead to softening of the film, too little water will lead to hard and brittle film. In order to ensure that the packaging film is intact during the storage of the gel and that the active content is high (45% or more), it is difficult to use traditional raw materials to simply increase the active content and directly obtain a product that meets the requirements.
SurfactantsThe main contributor to the detergency effect in laundry gels are surfactants, consisting of anionic surfactants and nonionic surfactants compounded for synergistic effects. During use, laundry gels may enter the gel zone the moment they are diluted with a large amount of water in the washing environment. When the use conditions are more extreme (such as low temperature) may also make the detergent gel, so it is particularly important to choose and use surfactants reasonably.
Anionic surfactants have excellent washing performance, strong decontamination ability, better biodegradability, lower cost, and obvious decontamination effect on particles, proteins and oily dirt. The formula can choose amine salts of fatty acids, sodium fatty alcohol polyoxyethylene ether sulfate (AES), sodium fatty alcohol polyoxyethylene ether carboxylate (AEC), α-alkenyl sulfonate (AOS), sodium fatty acid methanesulfonate (MES), dodecylbenzenesulfonic acid monoethanolamine salt (dodecylbenzenesulfonic acid MEA salt) and other common raw materials. Due to the low water content of the formulation, monoethanolamine or triethanolamine should be selected to generate amine salts when performing the neutralization reaction. Among them, amino acid type surfactant is the hottest and the main mild and non-irritating surfactant nowadays, which not only has a wide source of biomass raw materials, mild performance and good biodegradability, but also has good emulsifying, wetting, solubilizing, dispersing and foaming performance, and at the same time, it can reduce the irritation of traditional surfactants. In the formulation of laundry gel, the content of anionic surfactant is around 10%. Since the overall water content of the formulation is required to be low, anionic surfactants with low water content should be selected as far as possible.
Nonionic surfactants are also important in formulations, and nonionic surfactants are superior to ionic surfactants in some respects. Because they are not in the ionic state in solution, they are highly stable, less susceptible to the presence of strong electrolyte inorganic salts, less susceptible to pH, and have good compatibility with other types of surfactants. In the formulation of laundry gels, the content of nonionic surfactants is about 30%, and fatty alcohol ethoxylates (AEO), isomeric fatty alcohol ethoxylates (ICEO), alkyl glycosides (APG), cocoamidopropyl amine oxides (CAO), fatty acid methyl ester ethoxylates (FMEE), and modified oil ethoxylates (SOE) are generally used.The upstream raw materials of AEO are Fatty alcohol and ethylene oxide (EO) , the number of EO has a big influence on the product performance, 9EO has strong decontamination power, 7EO has good permeability and wettability. Compared with AEO series, isomeric alcohol ether nonionic surfactants are characterized by low pour point, narrow gel range, fast dissolution, strong wetting power, low foam and easy rinsing, and good compatibility with anionic surfactant formulations, which can reduce the foam of the laundry beads, reduce the number of times of rinsing, and achieve the purpose of improving efficiency and saving energy. FMEE has excellent calcium soap dispersion, hard water decontamination performance, oil removal performance, good low-temperature fluidity and narrow gel zone, so it is suitable to be used in laundry gel beads.SOE is a new type of polyoxymethylene nonionic surfactant modified with natural oils and fats as raw materials, it has excellent surface activity and biodegradability, low irritation, low foaming, good low-temperature fluidity, good emulsification ability to oils and fats, and it can improve the product’s low-temperature stability to a certain degree, and it has comparable performance to AEO-9, which can improve the product’s low-temperature stability. It has comparable decontamination ability to AEO-9, and it has the characteristics of non-gel zone, which can be mixed with water at any ratio without gel, and it has good compatibility, which can reduce the viscosity of the formula, and it is the ideal raw material for laundry gel beads.
Detergent additives commonly used detergent additives: chelating agents, stabilizers, anti-redeposition agents and so on. Because domestic water contains calcium and magnesium ions and transition elements such as iron, manganese, mace, they will affect the use of surfactants, so in the formula will add a small amount of efficient chelating agent chelating these metal ions. Chelating agents include sodium citrate, ethylenediaminetetraacetic acid sodium salt (EDTA), tetrasodium glutamate diacetate (GLDA) and tetrasodium methylglycinate diacetate (MGDA). EDTA, a widely used carboxylic acid-based chelating agent, has long been considered unfriendly to the environment due to its non-biodegradable nature. On the other hand, another new chelating agent, GLDA, which is based on monosodium glutamate (MSG), with 48% w/w derived from natural plant products, is biodegradable, with a biodegradation rate of more than 80% in 28d.
Stabilizers such as palm kernel oleamide, hydrogenated castor oil, sodium xylene sulfonate, alkyl diphenyl ether disulfonate, urea, etc., are mainly used to improve and increase the viscosity of the fluid, maintain its high and low temperature stability, and also emulsify, stabilize, or make the suspension state. By adding stabilizers to change the morphology of surfactant micelles, surfactants can be prevented from gelation, so that it is easier to flow from the liquid crystal phase to more easily dissolved spherical or rod-shaped micelles. The amount of urea added to laundry gel beads is generally 2% to 10%, and the addition of urea can play a solubilizing role, reduce the viscosity of the formulation system, and also increase the transparency of the product.
Antideposition agents are polymers with particle dispersing function to inhibit hydrophilic particles of dirt and oily dirt from being washed and redeposited on the fabric surface. Commonly used anti-redeposition agents include polyacrylic acid, polyethyleneimine, polyvinyl alcohol, polyvinylpyrrolidone and so on. Acrylic acid and styrene copolymer has good compatibility, solubilizing effect on the system, has good chelating calcium and magnesium ions, to prevent the shedding of dyes transferred to other fabrics, can improve the decontamination power of the formula. On the one hand, the polymer can prevent calcium carbonate and other non-water-soluble inorganic salts from being deposited on fabrics through chelation and crystal surface modification, especially under high temperature and high water hardness washing conditions; on the other hand, the anionic portion of the acrylate can be adsorbed onto stain particles to make the surface of the stains negatively charged, and the fabrics are usually also negatively charged, which produces static repulsion to make the stains suspended and effectively inhibit the stains from being deposited onto the fabrics again. This effectively prevents the stains from being deposited on the fabric and reduces the gray and hard condition of the fabric after several washes.
Organic solvents can solve the gel phenomenon and delamination that occurs under high content of active substances, and most surfactants are more soluble in organic solvents than in water. Commonly used solvents are ethanol, ethylene glycol, propylene glycol, butylene glycol, glycerol, diethylene glycol, diethylene glycol, sorbitol, polyethylene glycol-200, ethoxylated benzenemethanol and so on, and the amount of additive is generally controlled at 15% to 25%. Some low-end products add a large number of cheap solvents to control costs, affecting product quality and bringing the safety of solvent use. Diethylene glycol is a “cosmetic safety technical specifications” in the prohibited group, the provisions of raw materials in the concentration of diethylene glycol impurities does not exceed 0.1%. Diethylene glycol mainly on the kidneys and the nervous system has a toxic effect, and can produce a variety of symptoms and performance after ingestion, the patient usually occurs acute renal failure, and may be accompanied by metabolic acidosis. If laundry gels containing diethylene glycol are accidentally ingested, there is a risk of damage to the body, so diethylene glycol should be avoided in formulations. It is also worth noting that the maximum historical use of polyethylene glycol-200 in drench cosmetics is 15%; according to the Ministry of Emergency Management’s List of Hazardous Chemicals, ethanol content of more than 24% is a hazardous chemical.
Laundry gels are increasingly utilizing bio-enzyme technology, whereby enzymes are paired with other ingredients in the formulation to achieve efficient stain removal and fabric care. Enzymes are highly effective, green stain removal ingredients, mainly including protease, lipase, cellulase, amylase, mannanase, etc. There are also some formulations that add complex enzymes to achieve synergistic effects.
Commonly used bacteriostatic agents include p-chloro-m-xylenol (PCMX), polyhexamethylenebisbiguanide (PHMB), and benzalkonium chloride, etc. However, attention should be paid to the matching with other components of the formulation or the use of multi-chamber packaging process to isolate the bacteriostatic components.
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