CN1993458A - Microcapsules - Google Patents

Abstract

A microcapsule for use in a liquid detergent composition, the microcapsule having a core and a polymeric polyanion-polycation complex shell, wherein the polyanion component is capable of gelling in the presence of calcium and has a storage modulus of less than about 150Pa when gelled with 0.05 moles/liter of calcium at an angular frequency of about 0.5rad/s and a polyanion concentration of about 3.8% by weight at 25 ℃. The invention also relates to a process for manufacturing the microcapsules, a liquid detergent comprising the microcapsules, and a method for cleaning using the liquid detergent.

Description

Microcapsules

technical field

The present invention belongs to the field of microcapsules, in particular it relates to microcapsules (having a core and a polymeric polyanion-polycation composite shell, wherein said polyanion is capable of forming a weak gel in the presence of calcium), their preparation, Liquid detergents (comprising microcapsules) and their use in laundry, dish cleaning and other applications.

Background of the invention

Liquid detergents containing microcapsules are very attractive to consumers. It is desirable to include microcapsules in liquid detergents not only for aesthetics but also for certain functions such as sequestration of incompatible ingredients, controlled and/or delayed release, etc. Ideally, the microcapsules are stably suspended in the liquid detergent and only dissolve/disintegrate upon application. This makes the design of microcapsules a great technical challenge. The conditions of the application can vary widely according to many factors, including cleaning temperature, hardness of the cleaning water, duration of the cleaning process, and the like.

The use of microcapsules in liquid detergents is known from the literature. WO 02/055649 discloses a method for producing washing and/or cleaning substances comprising microcapsules with semi-permeable capsule shells (membranes) by complexing suitable polyelectrolytes.

The semi-permeable microcapsules known from the literature do not appear to be strong enough to withstand the manufacturing process and transport of liquid detergents and yet at the same time be able to rupture in use without leaving residues. Residue generation is made worse by stressful use conditions such as low temperatures, hard water and short wash durations.

It is an object of the present invention to provide strong microcapsules for use in liquid detergents which are capable of dissolving/disintegrating under many conditions, including stressed conditions. Specifically, the microcapsules should be suitable for use in liquid laundry detergents, capable of dissolving/disintegrating without leaving residues, even when using heavily loaded tumblers, short wash cycles, low wash temperatures and/or The same goes for hard water.

Summary of the invention

Microcapsules with a core and a polymeric polyanionic-polycation composite shell for use in liquid detergents should be designed such that they can be stably suspended in a liquid matrix, withstand manufacturing and shipping conditions, and be Dissolve/disintegrate. The microcapsules have a semi-permeable membrane (shell) that allows ions to migrate by osmotic effects between the core and the liquid or gel matrix of the detergent until complete equilibrium is reached, thereby contributing to the physical stability of the microcapsules in the matrix. Without being bound by theory, it is believed that when a detergent containing microcapsules is introduced into fresh water, for example during a cleaning process, the ionic strength gradient between the wash water and the microcapsules draws water into the core, exerting high The pressure caused the shell to disintegrate. This mechanism together with the shear applied during the cleaning process leads to the destruction of the microcapsules in use.

Microcapsules have been found to be prone to residue formation. This tendency has been found to be exacerbated under stressed conditions such as heavily loaded drums, short cleaning cycles, low temperatures and hard water conditions. The microcapsules of the present invention do not generate residues under stressed conditions.

Tap water (which contains metal ions such as calcium) is often used for cleaning with liquid detergents. Liquid detergents may also comprise calcium ions as a cleaning ingredient and/or as part of the aqueous matrix, eg for enzyme stabilization. Without being bound by theory, it is believed that the polyanions of the microcapsules tend to interact, especially cross-link, calcium from clean water, liquid detergent, or both. This interaction can lead to increased gelation of the polyanion. If the gel formed is too firm, it will not dissolve/disintegrate in water, leaving a residue on the item being cleaned.

In the case of a washing process, the microcapsules may be exposed to high concentrations of calcium in the wash liquor from different sources such as water supply, the wash load itself, previously washed clothes (which may be contained in the drying Calcium left after the water evaporates during the process), some dirt, etc. Liquid laundry detergents tend to bind relatively all calcium and other hardness ions, ie they cannot bind all the calcium present in the wash process, especially under stressful conditions.

According to a first aspect of the present invention there are provided microcapsules for use in liquid detergent compositions, said microcapsules having a core and a polymeric polyanion-polycation composite shell. Polyanionic components in aqueous solution are capable of forming weak gels in the presence of calcium. A weak gel is understood to be a polyanion-calcium gel formed from 0.05 mol/L calcium (released in situ by a Ca-EDTA solution, as described below) and having a storage modulus of less than about 150 Pa. Storage modulus was measured as described below.

A preferred polyanion for use in the microcapsules of the present invention is alginate. Alginate is the generic name given to alginic acid and its salts. Alginic acid is a linear polysaccharide consisting of (1,4)-linked β-D-mannuronate (M) and its C-5 epimer α-L-guluronate (G ) residues arranged in an irregular block pattern along the linear chain. The chemical composition and sequence of the M and G blocks depend on the biological source, growth and seasonal conditions. There are three adjustable blocks in alginate, they are MM, GG and MG. The ratio of mannuronic acid to guluronic acid units is considered the M:G ratio. In a preferred embodiment, the polyanion is alginate having an M:G ratio of at least about 1:1, preferably at least about 1.1:1, more preferably at least about 1.3:1, and even more preferably at least about 1.5:1. ratio. The alginate preferably has a GG block fraction of less than about 0.5, more preferably less than about 0.4, and even more preferably less than about 0.3. The alginate preferably has a molecular weight of less than about 0.83 ag (500 KDa). Furthermore, without being bound by theory, it is believed that divalent and multivalent cations form stronger gels with G residues, especially blocks of G residues, without M residues, and this leads to Poor dissolution/disintegration properties and consequent residue formation. Divalent cations, especially calcium ions, participate in the interchain bonding between G blocks and form a three-dimensional network in the form of a gel. The binding region between the G blocks is described by the so-called "egg-box model".

The most preferred alginates for use in the microcapsules of the present invention have: i) an M of at least about 1:1, preferably at least about 2:1, more preferably at least about 3:1, and even more preferably at least about 4:1 :G ratio; ii) a GG block fraction of less than about 0.5, more preferably less than about 0.4, and even more preferably less than about 0.3; and iii) a molecular weight of less than about 0.83 ag (500 KDa).

The microcapsules of the present invention are preferably spherical with a diameter of about 0.1 to about 10 mm and should be readily visible when placed in a liquid detergent. Visibility can be achieved by color contrast, for example by having a colored transparent or translucent (ie see through) liquid containing different colored microcapsules or having a colorless liquid containing colored microcapsules, or vice versa.

Pigments, when present, preferably comprise from about 0.001% to about 0.2%, more preferably from 0.06% to about 0.1%, by weight of the microcapsules. The microcapsules of the present invention preferably contain less than about 0.05%, more preferably less than about 0.01%, by weight of pigment, and even more preferably they are pigment-free. When the microcapsules are used in the cleaning process, low or no pigment content helps reduce residue formation.

The microcapsules of the invention preferably comprise in the core an emulsified oil which gives the microcapsules a white appearance even in the absence of pigments or dyes.

In another aspect of the present invention, microcapsules for use in liquid detergent compositions are provided, the microcapsules have a core and a polymeric polyanion-polycation composite shell, wherein the polyanion component is alginate, the The alginate has a ratio of mannuronic acid to guluronic acid units of at least about 1:1, preferably at least about 1.1:1, more preferably at least about 1.3:1, and even more preferably at least about 1.5 : 1. The alginate preferably has a GG block fraction of less than about 0.5, more preferably less than about 0.4, and even more preferably less than about 0.3. The alginate preferably has a molecular weight of less than about 0.83 ag (500 KDa). The microcapsules preferably contain less than about 0.05%, more preferably less than about 0.01%, by weight of pigment, and even more preferably they are pigment-free. The microcapsules preferably contain emulsified oil in the core.

In a preferred embodiment, the microcapsules are capable of withstanding a force (measured as described below) of from about 20 mN to about 20,000 mN, preferably from about 50 mN to about 15,000 mN, and more preferably from about 100 mN to about 10,000 mN, before rupture . This strength makes them suitable for industrial operations, including liquid detergent manufacturing processes. They withstand pumping and mixing operations without significant breakage and are stable during shipping. At the same time the microcapsules are prone to disintegration in use even under stress. The microcapsules have a wide operating window, eliminating the need to design different microcapsules for use under different conditions.

According to the method aspect of the invention, there is provided a method of making microcapsules for use in liquid detergent compositions, the microcapsules having a core and a polymeric polyelectrolyte composite shell. The microcapsules are made of a polyanionic component capable (as described above) of forming a weak gel in aqueous solution in the presence of calcium. The method comprises the steps of:

a. forming a first solution comprising a polyanionic component;

b. forming droplets of the first solution; and

c. introducing the droplet into a second solution comprising a polymerized polycation component, the polycation

The cationic component is capable of reacting with the polyanionic component to form a complex on the droplet surface.

The term "solution" as used herein includes liquid or gel compositions having one main component and at least one second component dissolved, dispersed or emulsified therein.

The polyanion is preferably an alginate having a M:G ratio of at least about 1:1, preferably at least about 2:1, more preferably at least about 3:1, and even more preferably at least about 4:1. The alginate preferably has a GG block fraction of less than about 0.5, more preferably less than about 0.4, and even more preferably less than about 0.3. The alginate preferably has a molecular weight of less than about 0.83 ag (500 KDa). The microcapsules preferably contain less than about 0.05%, more preferably less than about 0.01%, by weight of pigment, and even more preferably the microcapsules are pigment-free. The microcapsules preferably contain emulsified oil in the core.

In a preferred embodiment, the second solution has a pH of about 1 to 4, more preferably about 1.5 to about 3, and even more preferably about 2 to about 2.5. A low pH promotes a short curing time which has a positive effect on the strength of the microcapsules. The polycation is preferably chitosan, preferably having a degree of acetylation of about 94%.

According to another aspect of the invention there is provided a liquid detergent composition comprising the microcapsules of the invention. In a preferred embodiment, the liquid detergent compositions comprise from about 0.5 to about 30%, preferably from about 2 to about 15%, by weight of the composition, of detergency builder. Builders improve the cleaning performance of the compositions herein and can include any masking, sequestering or precipitating type. Examples of such builders include _C12-18 fatty acids and citric acid, typically neutralized with alkali metal hydroxides, amines or alkanolamines. A preferred builder for use herein is a mixture comprising from about 2% to about 15% by weight of the composition of a _C12-18 fatty acid and citric acid in a weight ratio of fatty acid to citric acid of about 10:1 to about 1:10, preferably about 5:1 to about 1:5, more preferably about 3:1 to about 1:3.

The present inventors have recently identified disadvantages that prior art microcapsules have when used in liquid laundry detergents. Known microcapsules do not appear to dissolve completely and therefore leave residues on washed clothes, especially under stressful conditions such as heavily loaded tumblers, short wash cycles, low wash temperatures and/or or in case of hard water. To address this recently identified problem, a preferred embodiment of the present invention provides a liquid laundry detergent comprising a suspension of visually distinguishable microcapsules in a liquid carrier, suitable for laundering fabrics, so The microcapsules preferably have a core and a polymeric polyanion-polycation composite shell, wherein the microcapsules have a Residue Index of less than about 1, preferably less than about 0.6, more preferably less than about 0.2 according to the Stressed Conditions Wash Test as defined herein . The liquid detergent of this embodiment preferably comprises the microcapsules of the invention as described above.

By "visually distinguishable microcapsules" is meant microcapsules (preferably spherical and having a diameter of about 0.1 to about 10 mm) that appear in the laundry detergent when the observer holds the liquid composition about 30 cm away from his eyes. is visible to the naked eye. As explained above, visibility is preferably obtained by the color contrast between the liquid detergent and the microcapsules. The microcapsules are preferably coloured, although transparent microcapsules can also be designed. Transparent microcapsules may also increase undesirable residues under stressed conditions.

The residual index is calculated according to the following method: 11 pieces of black clothes with a total weight of about 3.5 kg are loaded in a Miele washing machine model W8810. A dosing sphere was placed in the center of the load containing 180ml of heavy duty laundry liquid (HDL) containing 1% by weight of microcapsules. Preferably, the HDL formulation is as described in Table 3 below.

The inlet water to the washing machine is at a temperature of 5°C (this can be achieved by the cooling system). The water hardness was 4 mmol of calcium and magnesium in a 3 to 1 ratio. A woolen cycle (30°C and 40 minute duration) was used. The laundered garments were visually rated to assess the presence of residue. Count the number of clothes that contain residue. This process was repeated four times and the number of garments containing residue was averaged over the four washes. This average is divided by the number of garments (11) to obtain the residual index.

In a method aspect of the invention there is provided a method of cleaning a soiled item or substrate comprising contacting the item or substrate with an aqueous solution comprising a liquid detergent composition of the invention. The method is suitable for a variety of applications including hard surface cleaning - manual and automatic dish cleaning, toilet rim cleaning, laundry, etc.

The method is particularly suitable for laundry washing. The liquid detergent composition of the present invention, when under stressed conditions (such as hard water i.e. above about 2mmol/l, preferably between about 3mmol/l and 6mmol/l, and more preferably about 4mmol/l calcium and magnesium (preferably in a 3 to 1 ratio) - and/or low inlet temperature - about 4°C to 6°C - and/or low program temperature - about 30°C - and/or heavy loads) are not being washed residue on clothing.

It is generally not possible to precisely control the temperature conditions applied in a washing machine, even if it is possible to preselect the program temperature. The washing machine is filled with water from the mains, and the water temperature at the inlet is controlled by external conditions and can vary widely depending on other factors in the weather. The water at the inlet is then heated up to the desired program temperature. There may be a considerable difference between the inlet water temperature and the program water temperature, so the temperature of the wash liquid may be low for a substantial part of the cycle. These conditions can favor gelation of the beads. This problem can be exacerbated when hard water is used and/or the machine drum is heavily loaded.

The current trend is to design washing machines with low energy consumption, usually including low temperatures, reduced agitation and shortened wash times. These conditions also favor the gelation of the microcapsules.

In another method aspect of the invention, a method of cleaning laundry without leaving visible residues on the clean laundry is provided. The cleaning is carried out in a washing machine under hard water conditions, i.e. above about 2mmol/L, preferably between about 3mmol/L and 6mmol/L, and more preferably about 4mmol/L of calcium and magnesium (preferably in a ratio of 3 to 1 The ratio). The cleaning method includes the steps of contacting the laundry with hard water and adding a liquid detergent. The liquid detergent preferably comprises from about 0.3% to about 3%, more preferably from about 0.5% to about 2%, and even more preferably from about 0.8% to about 1.5%, by weight of the liquid detergent, so The microcapsules have a core and a polymeric polyanion-polycation composite shell. The liquid detergent preferably provides from about 10 to about 2000 ppm, more preferably from about 50 to about 1200 ppm, and even more preferably from 500 to 900 ppm builder in the wash liquid.

According to the test described below, the microcapsules leave no visible residue on laundry. Preferably, the polyanionic component of the microcapsules used in the cleaning method is capable of forming a weak gel in aqueous solution in the presence of calcium and has a storage modulus (measured as described below) of less than about 150 Pa. A preferred polyanion is alginate having a M:G ratio of at least about 1:1, preferably at least about 1.1:1, more preferably at least about 1.3:1, and even more preferably at least about 1.5:1. The fraction of GG blocks is preferably less than about 0.5, more preferably less than about 0.4, and even more preferably less than about 0.3. The molecular weight is preferably less than about 0.83 ag (500 KDa).

Use the following test to evaluate whether a wash method leaves visible residue on clean clothes. About 12 dark colored garments weighing a total of about 4kg to 4.5kg were washed on a Miele Novotronic W8810 machine on the cotton short cycle program. The water temperature at the inlet was about 5°C to 6°C, the washing temperature was about 30°C, and the water hardness was 4mmol/L. 180 mL of liquid laundry detergent (containing 1% microcapsules by weight of the composition) was placed in a dispensing ball and the ball was placed in the center of the drum. At the end of the procedure, the garments were visually inspected. If less than 20%, preferably less than 10%, and even more preferably less than 5% of the garments have residue, it can be concluded that the wash process leaves no visible residue.

Detailed description of the invention

The present invention contemplates microcapsules (sometimes referred to as beads) for use in liquid detergents, methods for their preparation, liquid detergents containing the microcapsules, and methods of cleaning using the liquid detergents. The microcapsules do not form strong gels, so they dissolve/disintegrate in use without leaving residues, even under stress.

The microcapsules preferably take the form of spherical beads having a diameter of about 0.1 to about 10 mm, comprising a core surrounded by a membrane. The membrane protects the core and any active material within the core from the surrounding medium.

The term liquid detergent as used herein includes all free-flowing fluids having cleaning properties, including liquids and gels for manual and automatic laundry, dish cleaning, hard surface cleaning, personal cleaning and toilet rim cleaning applications.

The microcapsules of the present invention are prepared by a process based on the reaction of two oppositely charged polyelectrolytes (also referred to herein as polyanions and polycations) capable of forming complexes. Polyelectrolytes suitable for use in the present invention may be synthetic or natural polyelectrolytes.

polyanion

Polyanions suitable for use in the present invention may be synthetic or natural polyanions which meet the requirement of being able to form weak gels in the presence of calcium and which are stable when at 25°C at an angular frequency of about 0.5 rad/s and by weight A polyanion concentration of about 3.8% gelled with 0.05 mol/L calcium has a storage modulus of less than about 150 Pa.

Synthetic polyanions may be selected from the group consisting of polyacrylates and polymethacrylates, polyvinyl sulfates, polystyrene sulfates, polyphosphates, and mixtures thereof. Natural polyanions may be selected from anionic gums including alginates, carrageenan, gellan gum, carboxymethylcellulose, xanthan gum, and mixtures thereof.

Preferred polyanions for use herein are alginates, more preferably Lamitex M45 (ex FMC), and Manutex RM, Kelgin HV, Manucol LH, Manucol DM and Manucol DH, all supplied by ISP. Most preferred are Manucol DM and Manucol DH.

Preferred alginates having a high content of mannuronic acid include those derived from the algae Ascophyllumnodosum or the algae Macroystis pyrifera.

Measurement of storage modulus of polyanions

The polyanion storage modulus was measured by crosslinking an aqueous solution containing 3.8% by weight polyanion with calcium to form a gel. Calcium-polyanion gels were prepared by in situ release of calcium cations from Ca-EDTA solution. In this way a homogeneous polyanionic gel is obtained and the problem of calcium concentration gradients in the gel is avoided. The method is based on the method proposed by X. Liu et al., Polymer, Vol. 44, pp. 407-412 (2003).

First, glucose was prepared by adding 0.3 g (99% purity) of D-glucono-delta-lactone (GDL, Sigma) to 19.7 g of water and stirring with a magnetic stirrer at 42 rad/s (400 rpm) for 2 minutes acid ester solution.

Next, a Ca-EDTA solution was prepared by adding 1 g of CaCl ₂ hexahydrate (98% purity) and 44.69 g of 0.01 mol/L aqueous EDTA to 21.51 g of water. The solution was stirred with a magnetic stirrer at a speed of 42 rad/s (400 rpm), and 0.1 N NaOH aqueous solution (about 9 g) was slowly added until the pH value stabilized at about 7.

A polyanion solution is prepared by adding 3.8 g of polyanion (preferably alginate) to the Ca-EDTA solution. The resulting solution was stirred for 3 minutes with a Turrax Ultra-Speed Stirrer: Move the Ultra-Speed Stirrer through the solution at 681 rad/s (6,500 rpm) for the first minute, 1414 rad/s (13,500 rpm) for the second minute, and A speed of 2251 rad/s (21,500 rpm) was used for the third minute.

The calcium polyanion solution was then prepared by adding the gluconate solution to the polyanion solution. The resulting solution was stirred in the same manner as the polyanionic solution, i.e. at 681 rad/s (6,500 rpm) for the first minute, 1414 rad/s (13,500 rpm) for the second minute, and 2251 rad/s (13,500 rpm) for the third minute. s (21,500rpm) speed. Gluconate causes the pH of the solution to decrease, and the combined stability constant of Ca-EDTA decreases accordingly, thereby releasing calcium. The resulting calcium polyanion solution was stored at 20°C for 24 hours.

The storage modulus was measured with a rheometer UDS 200 Paar Physica with cone and plate fixtures. The diameter and angle of the cone are 50 mm and 0.04 rad, respectively. Measurements were performed at 25±0.1°C. After calibrating the device (as indicated in the manual), the strain was set at 0.5%. A frequency sweep is performed in the range of 0.1 to 100 s ^-1 . Measure 25 points in automatic mode. The storage modulus is plotted against frequency.

Measurement of Molecular Weight of Polyanions

Molecular weights were determined by gel permeation chromatography (GPC) and data processing was performed using conventional calibrated GPC techniques. Molecular weights are determined by calibration with a set of narrowly distributed reference materials: polyethylene oxide ( PEO) standard.

A Waters Alliance 2695 Separation Module Gel Permeation Chromatography with a Viscotek triple detector (using a differential refractive index detector for routine calibration) was used. The control system is WatersEmpower and Viscotek three detector software. Detection was performed using a Viscotek differential refractive index detector. The module consisted of two Waters Ultrahydrogel 300 x 7.8 mm columns, one containing Ultrahydrogel Linear and the other Ultrahydrogel 102. The eluent was 0.1 M Na ₂ HPO ₄ aqueous solution dissolved in acetonitrile at a volume ratio of 90:10. The sample was injected as 100 μL of 2.5 mg/mL polyanion solution at a flow rate of 0.8 mL/min.

The molecular weight of unknown samples was determined by "slicing" the chromatographic line along the time/volume axis and then reading the slice molecular weight each time from the PEO standard curve (Log molecular weight versus retention time or volume). Weight average molecular weights were calculated based on slice molecular weights and their relative intensities. Calibration, sectioning and calculation of molecular weight are all performed by GPC processing software.

polycation

Suitable cationic synthetic polyelectrolytes may be selected from the group consisting of: poly-(N,N,N-trialkylammonium alkyl)acrylates, poly-(N-alkylpyridine) salts, polyethylenimines, Aliphatic ionenes, poly-(diallyldialkyl) salts, and mixtures thereof, wherein the alkyl group is preferably a short chain having 1 to about 4 carbon atoms, preferably methyl.

Suitable cationic natural polyelectrolytes may be selected from the group consisting of chitosan, chitosan derivatives such as quaternized chitosan, and aminoalkylated and quaternized cellulose and poly-L-lysine, and mixtures thereof.

Preferred for use herein are sodium alginate (for the first solution) (preferably Manucol DH or DM) with poly-(dialkyldimethylammonium) chloride, chitosan polymers (with about 0.016 to 1.66 ag (about 10 to 1,000 kDa), preferably about 0.083 to 0.83 ag (about 50 to 500 kDa) molecular weight), chitosan oligomers (having about 0.00045 to about 0.015 ag (about 300 to about 9,000 Da), preferably about 0.00083 to about 0.0083 (about 500 to about 5,000 Da) molecular weight) or a mixture of chitosan polymers and oligomers (for the second solution). These combinations are preferred for their short reaction times and low permeability of the resulting microcapsules, especially the combination of sodium alginate and poly-(dialkyldimethylammonium) chloride. Permeability of the membrane is preferred, allowing water or solvent to migrate between the liquid detergent and the core of the microcapsules, but preventing dissolution of the active substance.

Force measurement before rupture

The pre-rupture force that the microcapsules can withstand can be measured by using a dynamic mechanical analyzer (PerkinElmer DMA 7e). Individual microcapsules were isolated from the stock solution (0.9% NaCl) and placed on the sample plate of the analyzer. The capsule was covered with a drop of 0.9% sodium chloride solution. To determine the force at the rupture point, static strain sweeps were performed during compression of the microcapsules with an increasing force of 20 mN/min applied. The applied force and the displacement of the squeezed capsule are automatically recorded. The rupture point corresponds to the first shoulder on the static force sweep curve, specifically the intersection of the two tangents closest to the lateral portions above and below the shoulder.

Preferably, the microcapsules of the present invention have a density at 25°C of about 900 to about 1,300 Kg/m ³ , more preferably about 950 to about 1,200 Kg/m ³ , and more preferably about 980 to about 1,100 Kg/m ³ .

The density of the microcapsules was determined using a Helium Pycnometer (Micromeritics AccuPyc 1330) at 21 °C and 172 kPa (25 psi.). The microcapsules were removed from the 0.9% sodium chloride stock solution and wiped lightly with tissue paper to remove excess liquid before taking measurements.

The microcapsules of the invention are preferably substantially spherical in shape, especially when they are suspended in a liquid detergent. Additionally, the microcapsules preferably have a diameter (measured as a comparable circular diameter) in the range of about 0.2 to about 8 mm, preferably about 0.5 to about 5 mm, and more preferably about 0.7 to about 4 mm. These ranges are preferred in view of microcapsules being visible to the naked eye and ease of manufacture.

The size and shape of the microcapsules can be characterized using an optical microscope (Leica MZ8) and an image analysis system (Leica Q500MC, Quips, UK). Before analysis, the microcapsules were removed from the 0.9% NaCl solution and placed on the microscope bench. During the measurement, the microcapsules were kept moist using 0.9% sodium chloride solution. Before processing the image, it should be verified that all capsules are measured as a single entity. The equivalent circular diameter is the diameter of a circular cross-section corresponding to the cross-sectional area of the particle.

The microcapsules preferably have an elasticity of at least about 30%, more preferably at least about 50%, and especially at least about 70% at 25°C. This elasticity can be calculated using the Kinetic Mechanical Analyzer described above. Elasticity is defined here as the deformation of the microcapsules in the direction of movement of the rupture front plate as a percentage of the corresponding undeformed capsule size. The elasticity of the microcapsules contributes to their mechanical stability in liquid detergents.

The core of the microcapsules preferably comprises the active substance. The shell may also optionally include an active substance. The active material is preferably selected from hydrophobic and non-hydrophobic materials having a molecular weight above about 12,000. Herein "hydrophobic material" is understood as a substance having an octanol-water partition coefficient at 25°C higher than about 1, preferably higher than about 1.2, and more preferably higher than about 1.5. The octanol-water partition coefficient of a substance is defined as the ratio of the concentration of the substance in the octanol phase to its concentration in the water phase at 25°C. Preferred hydrophobic materials for use herein include perfume oils, silicone fluids and gums, surfactants, and vitamin oils. Preferred non-hydrophobic materials having a molecular weight above about 12,000 for use herein include enzymes. Other suitable active substances include those listed below. The microcapsules can provide protection for the active substances, reducing or avoiding the interaction between the active substances in the core and the substances in the liquid matrix of the liquid detergent, thereby improving the chemical stability of sensitive substances such as enzymes and fragrances. The retention of the active substance in the core of the microcapsules according to the invention is higher than in microcapsules produced by polymeric crosslinking, for example using calcium as crosslinking agent.

The core of the microcapsules of the present invention preferably includes an amount of density modifier to reduce the density of the microcapsules by at least about 10%, more preferably at least about 15%, at 25°C. Density modifiers help to create microcapsules of predetermined density, which can be suspended in liquid detergents without or with low levels of structurants or thickeners. "Low level"means less than about 5%, preferably less than about 1%, and more preferably less than about 0.2%, by weight of the detergent matrix, of structurant or thickener. By comparing two similar microcapsules (the first made from a solution containing a given amount of density modifier and the second from a solution in which the density modifier has been replaced by the same weight of water) Find the density reduction value. Density modifiers suitable for use herein preferably have a density of less than about 1,000 Kg/m ³ , more preferably less than about 990 Kg/m ³ , and greater than about 700 Kg/m ³ , especially greater than about 800 Kg/m ³ . Suitable density modifiers include hydrophobic materials and substances with a molecular weight above about 12,000. The density regulator is preferably insoluble in water but dispersible in water with or without the aid of a dispersant. If the active substances meet the above requirements, they can act as density regulators. Preferred density modifiers for use herein are selected from the group consisting of silicone oils, petrolatum, vegetable oils (especially sunflower oil and rapeseed oil), and ^hydrophobic solvents having a density of less than about 1,000 Kg/m at 25°C (such as limonene and octane). Preferred density modifiers are emulsified in the core of the microcapsules, with the added function of imparting a white appearance to the microcapsules.

method

The method of the present invention involves complexation of polyanions and polycations. Droplets of the first solution comprising polyanions are dropped into the second solution comprising polycations. When said polyanion is in aqueous solution, it meets the requirement of having a storage modulus of less than 150 Pa under the conditions defined above.

Preferably, the density modifier is present in the first solution in an amount of from about 5% to about 50%, preferably from about 10% to about 30%, by weight.

The first and/or second solution may comprise any solvent, including water and organic solvents. The first and second solutions are preferably aqueous so that the resulting microcapsules are readily compatible with most liquid detergents, which are usually aqueous. The first and second solutions are preferably aqueous compositions in which oppositely charged polyelectrolytes are dissolved.

The method of the invention is preferably performed at ambient temperature, thereby reducing operating costs and allowing the encapsulation of heat sensitive substances.

The method of the present invention is fast, simple, universal and capable of high output, so it is suitable for large-scale production.

The droplets of the first solution can be produced by a jet cutting method. Jet cutting enables high yields and narrow distribution of droplet sizes, and allows handling of highly viscous solutions, i.e. solutions having greater than about 200 mPa.s, preferably greater than about 1,000 mPa.s when tested at 1 s ⁻¹ and 25° C., and More preferred are viscosities greater than about 2,000 mPa.s. Jet cutting can also handle solutions with complex rheological properties, such as shear-thinning solutions.

The jet of the first solution is preferably passed through a nozzle having a diameter of from about 0.2 mm to about 8 mm, preferably from about 0.5 mm to about 4 mm, and at a rate of from about 0.5 g/s to about 20 g/s, more preferably from about 1 g/s to A rate of about 6g/s passes through.

The jet is preferably cut by mechanical means, especially preferred is a rotating cutting wire having a diameter of about 10 μm to about 1,000 μm, more preferably about 50 μm to about 500 μm, and a cutting speed of about 52 rad/s (500 rpm) to about 1047 rad/s ( 10,000 rpm), more preferably from about 105 rad/s (1,000 rpm) to about 628 rad/s (6,000 rpm).

The first solution preferably comprises from about 1% to about 15%, more preferably from about 2% to about 10%, especially from about 3% to about 8%, by weight of the solution, of the first polyanion such that Amounts are preferred for both strength and low permeability of the resulting microcapsules. The first polyelectrolyte has a viscosity, when measured at a shear rate of 1 ^s at 25° C. and at a concentration of 1% by weight, preferably of at least 100 mPa.s, more preferably of at least 300 mPa.s, such a viscosity for High strength of the resulting microcapsules is preferred. A preferred method for use in the present invention is a first solution comprising from about 2% to about 7%, more preferably from about 3% to about 6%, especially from about 3.5% to about 5% sodium alginate by weight. The sodium alginate has a viscosity of at least 100 mPa.s, preferably at least 300 mPa.s when measured at 25°C at a shear rate of 1 s ⁻¹ and at a concentration of 1% by weight.

Solutions for use in the process of the invention may be prepared using any solvent, however aqueous solutions are preferred due to their practical and environmental properties and because of the compatibility of water with most active substances and liquid detergents. It is preferred to carry out the process at ambient temperature, which is preferred when handling heat sensitive substances such as fragrances and enzymes. However, if encapsulating substances that are not heat sensitive, the solution of the process can be heated to increase the kinetics of the complexation reaction.

The first solution preferably comprises a density modifier and/or an active substance dissolved, suspended or emulsified therein. The first solution may also contain dispersants or emulsifiers, especially if the active substance is hydrophobic, to facilitate the suspension or emulsification process, preferred dispersants for use herein are polymers, especially polyvinyl alcohol. Preferred emulsifiers for use herein are surfactants. Dispersants and/or emulsifiers are generally used in low levels, suitable amounts useful herein being from about 0.1% to about 5%, preferably from about 0.2% to about 3%, by weight of the first solution.

Active substances suitable for use herein include any substance that aids in the cleaning process such as surfactants, enzymes, builders and bleaches; and substances that provide additional benefits such as suds suppressors, fragrances (especially fragrance oils) , vitamins, antimicrobials, color protectants, care aids, finishing agents (especially fabric softening, drying and shine aids).

The microcapsules are preferably coloured, so they are easily visible when placed in a liquid detergent.

Droplets can be formed by any known method. The droplets are preferably made into a continuous jet on their way to the second solution by pressurizing the first solution through a nozzle and cutting the jet into cylindrical pieces with a cutting tool (which then form droplets due to surface tension) And formed. A preferred cutting tool comprises a rotary cutting wire. Methods and devices suitable for forming droplets are described in DE 4424998 and WO 00/48722.

The volume of the second solution is usually at least 10 times larger than the volume of the droplet, preferably at least 100 times larger, and more preferably at least 1,000 times larger, therefore, the amount of the second polyelectrolyte is sufficient to exceed the amount of the first polyelectrolyte, so that the second The concentration of polyelectrolyte in the solution is not critical. The concentration of the second polyelectrolyte is preferably from about 0.5% to about 5%, more preferably from about 0.8% to about 2%, by weight of the solution. The pH of the second solution is selected according to the pH conditions at which the second polyelectrolyte dissolves. Adjust the residence time of the droplet according to the desired thickness of the shell. Usually the reaction is carried out under stirring conditions. The second solution has a pH of preferably about 1 to about 4, more preferably about 1.5 to 3, and even more preferably about 2 to about 2.5.

The liquid detergents of the present invention comprise from about 0.5% to about 30%, preferably from about 0.7% to about 10%, more preferably from about 0.8% to about 2%, by weight of the composition, of microcapsules. Suitable surfactants for use in the liquid detergents of the present invention are well known and may be selected from anionic, nonionic, amphoteric and cationic surfactants depending on the particular application of the detergent.

Builders suitable for use in the liquid detergents of the present invention include builders that form water-soluble hardness ion complexes (masking builders) such as citrates and polyphosphates (such as sodium tripolyphosphate and tripolyphosphate hexahydrate). sodium polyphosphate, potassium tripolyphosphate, and mixed sodium and potassium tripolyphosphate salts); and builders that form hardness ion precipitates (precipitating builders) such as carbonates (eg, sodium carbonate). The combination may be selected from organic phosphonates and amino phosphonates, amino carboxylates, polyfunctionally substituted aromatic compounds, and mixtures thereof in acid or salt form. Also suitable for use herein are precipitating builders such as fatty soaps (fatty acids neutralized with sodium or potassium hydroxide or alkanolamines).

The detergent compositions herein may also comprise one or more detergent actives or adjunct ingredients. Detergent actives may be selected from conventional detergent ingredients such as bleaching systems (including bleaches and bleach activators), sources of alkalinity, enzymes, and the like. Detergent adjunct components may be selected from finish and care agents. Some of these ingredients can be used in microcapsules or liquid detergent matrices or both.

The detergent matrix is preferably transparent or translucent, more preferably transparent, contains colored microcapsules and is packaged in clear, transparent or see-through packaging.

Example

Example 1

380 g of sodium alginate from brown algae (Manucol DM from ISP - having a MG ratio of about 61/39, a GG fraction of about 0.21 and a molecular weight of about 0.0007 ag (448 KDa)) and 40 g of titanium dioxide (from Sigma Aldrich , product number T8141) was added to 9580 grams of deionized water and mixed to form a solution.

A throughput of 5.20 g/s of the above solution was pressurized through a 1.0 mm nozzle and cut at 356 rad/s (3400 rpm) using a rotary cutting tool (JetCutter, from GeniaLab) containing 24 200 micron thick wires. Speed cutting to form spherical droplets between 1750 and 2250 microns in diameter. The droplets were dropped into a stirred hardening bath containing 75 liters of a 1% chitosan solution (Chitoclear from Primex) adjusted to pH 1.5 with HCl.

After a hardening time of 15 minutes, the microcapsules were separated from the chitosan solution by filtration, washed with copious amounts of water and stored in 1.0% NaCl solution.

Example 2

The filtered microcapsules of Example 1 were stirred into a liquid laundry detergent prepared as described below. The microcapsules remain uniformly suspended in the liquid detergent.

Example 3

Microcapsules of the formulation listed in Table A were prepared according to the following procedure: 80 g of polyvinyl alcohol ((PVA), Mowiol 3-83 from Clariant)) was added to 500 g of deionized water and stirred at 70°C to form a clear The solution. 7040 g (in the case of examples A1 and A2) and 6850 g (in the cases of examples A3 to A5) of deionized water were added to the solution to dilute the system.

Sodium alginate obtained from brown algae (340 grams of Manucol DM in the case of Examples A1 and A2, ex ISP, had a M:G ratio of about 61/39, a GG fraction of about 0.21 and a molecular weight of about 0.74 ag (448KDa); and in the case of Examples A3 and A5, 530 grams of Manucol DH from ISP with a M:G ratio of about 61/39, a GG fraction of about 0.18 and a molecular weight of about 0.48ag (289KDa )), 30 g of bactericide (ThorActicide MBS), 10 g of titanium dioxide (from Sigma Aldrich, product number T8141) and aqueous polyvinyl alcohol were mixed to form a solution.

1000 grams of spice and 1000 grams of sunflower oil (eg ASDA sunflower oil) were pre-sheared for 5 minutes to form a one-phase liquid. This mixture was immediately added to the alginate mixture to form an opaque white liquid.

The resulting solution was squeezed to form droplets, which were treated as in Example 1 in a chitosan (Chitoclear FG95 from Primex) solution (with the pH indicated in Table A).

Table A: Microcapsule composition (% by weight) Example A1 A2 A3 A4 A5 alginate 3.4 (DM) 3.4 (DM) 5.3 (DH) 5.3 (DH) 5.3 (DH) sunflower oil 10 10 10 10 10 PVA 0.8 0.8 0.8 0.8 0.8 spices 10 10 10 10 10 TiO2 0.1 0.1 0.1 0.1 0.1 Acticide MBS 0.3 0.3 0.3 0.3 0.3 Chitosan 0.17 0.17 0.17 0.17 0.17 water to margin to margin to margin to margin to margin pH chitosan 1.5 2.0 2.5 2.0 2.5

Example 4

The microcapsules leached from Example 3 were stirred into a liquid laundry detergent prepared as described below. The microcapsules remain uniformly suspended in the liquid detergent.

The structured liquid detergent matrix is prepared by mixing an aqueous premix of conventional heavy duty liquid (HDL) detergent composition ingredients with a structuring agent premix. Each of these two premixes was prepared as follows:

HDL premix

The HDL component premix is prepared by mixing the HDL component with water in a suitable container with suitable agitation. The composition of the resulting premix is shown in Table I.

Table I

HDL component premix components Concentration (weight percent) C12LASC14-15E08 Alcohol Ethoxylate C12-14 Amine Oxide Citrate C12-18 Fatty Acidase (Protease, Amylase, Mannanase) MEA-Borate DTPMP ¹ Chelating Agent Ethoxylated Polyamine Dispersant Silicone/Silica Foam Depressant Ethanol Propylene Glycol NaOH Fragrance, Brightener, Hydrotrope, Colorant, Other Minor Components Water 7.85.91.02.15.40.61.60.21.20.0021.55.23.24.4 margin to 100% ¹ sodium diethylenetriaminepentamethylphosphonate

Structured Reagent Premix

A structuring agent premix was prepared by mixing the hydrogenated castor oil and other structuring agent premix ingredients shown in Table II with water under certain conditions. Specifically, the components of Table II except hydrogenated castor oil were mixed, and the resulting mixture was heated to 90°C. The hydrogenated castor oil is then added and the mixture is maintained under stirring until all of the hydrogenated castor oil is emulsified. After complete emulsification, the mixture was rapidly cooled to 70°C and held at this temperature until all of the hydrogenated castor oil recrystallized. At this point, the structuring reagent premix was allowed to cool slowly to ambient temperature. The resulting structuring reagent premix composition is shown in Table II.

Table II

Structured Reagent Premix Component concentration (weight percent) Hydrogenated Castor Oil C12HLAS Sodium Metaborate NaOH Water 4.016.01.53.5 Margin to 100%

HDL

Next, 2.5 parts of the structuring agent premix of Table II were slowly added to 96.5 parts of the HDL component premix of Table I with gentle agitation to form the structured detergent matrix.

The microcapsules formed according to the procedure of Example 1 were mixed with a structured aqueous liquid detergent composition matrix. This is achieved by slowly adding the microcapsules to the structured liquid matrix while maintaining gentle agitation. Sufficient microcapsules are added to make up 1% by weight of the formed composition. The composition of the resulting heavy duty liquid laundry detergent is shown in Table III.

Table III

Liquid laundry detergent containing microcapsules components Concentration (weight percent) C12LASC14-15E08 Alcohol Ethoxylate C12-14 Amine Oxide Citrate C12-18 Fatty Acidase (Protease, Amylase, Mannanase) MEA-Borate DTPMP1 Chelating Agent Ethoxylated Polyamine Dispersant 7.95.71.02.05.20.61.50.21.2 Silicone/Silica Foam Suppressor Ethanol Propylene Glycol NaOH Hydrogenated Castor Oil Microcapsules of Example 1 Fragrance, Brightener, Hydrotrope, Colorant, Other Minor Components Water 0.0021.45.03.20.11.04.2 margin to 100%

180 mL of liquid detergent containing microcapsules was placed in the dosing ball. A wash load of 4kg to 4.5kg of dark clothes was placed in the Miele Novotronic W8810 at 30°C using the cotton short cycle. The temperature of the incoming water is cooled to a temperature of 5°C to 6°C. Place the dosing ball near the center of the wash load. The hardness of water is 4mmol/L. At the end of the cycle, visually inspect the laundry. No residue was found.

Claims (19)

1. microcapsule that are used for liquid detergent composition, described microcapsule have core and polymeric polyanion-polycation composite shell, wherein said polyanionic component can be at gelationization in the presence of the calcium, and has the storage modulus less than about 150Pa when at 25 ℃ of calcium gelationizations with the polyanion concentration of the radian frequency of about 0.5rad/s and about by weight 3.8% and 0.05 mol.

2. microcapsule as claimed in claim 1, wherein said polyanion are alginate, the unitary ratio of mannuronic acid that described alginate have and guluronic acid (M: the G ratio) be at least about 1: 1.

3. as claim 1 or the described microcapsule of 2 aforementioned each claims, wherein the mark of guluronic acid/guluronic acid (GG) block is less than about 0.5.

4. described microcapsule of each claim as described above, wherein said polyanion has the molecular weight less than about 500KDa.

5. described microcapsule of each claim as described above, described microcapsule comprise and are less than approximately 0.05% by weight, preferably are less than about 0.01% pigment.

6. described microcapsule of each claim as described above, described microcapsule comprise emulsive oil.

7. microcapsule that are used for liquid detergent composition, described microcapsule have core and polymeric polyanion-polycation composite shell, wherein said polyanionic component is alginate, the unitary weight ratio of mannuronic acid that described alginate have and guluronic acid (M: the G ratio) be at least about 1: 1.

8. described microcapsule of each claim as described above, wherein said microcapsule can withstand about 20mN to about 20 before breaking, the power of 000mN.

9. a manufacturing is used for the method for the microcapsule of liquid detergent composition, and described microcapsule have core and polymeric polyelectrolyte composite shell, said method comprising the steps of:

A. form first solution that comprises polyanionic component, described polyanionic component can be at gelationization in the presence of the calcium, and has the storage modulus less than about 150Pa when at 25 ℃ of calcium gelationizations with the polyanion concentration of the radian frequency of about 0.5rad/s and about by weight 3.8% and 0.05 mol;

B. form the droplet of described first solution; With

C. described droplet introducing is comprised in second solution of polymeric polycation component, described polycation component can be reacted to form mixture on described droplet surface with described polyanionic component.

10. method as claimed in claim 9, the content of polyanion is about 2% to about 6% by weight in wherein said first solution.

11. it is about 1 to 4 that method as claimed in claim 9, wherein said second solution have, preferred about 1.5 to 3, and 2 to 2.5 pH more preferably from about.

12. microcapsule, described microcapsule can be by obtaining as each described method in the claim 9 to 11.

13. a liquid detergent composition, described composition comprise tensio-active agent and as each described microcapsule in claim 1 to 8 or 12.

14. liquid detergent composition as claimed in claim 13, described composition comprise sequestrant/washing assistant of about by weight 0.01% to about 30%.

15. liquid laundry detergent, described washing composition comprises the suspension of the distinguishable microcapsule of vision in liquid vehicle, wherein said microcapsule have less than 1 according to the stress condition washing test that is subjected to defined herein, preferably less than 0.6, are more preferably less than 0.2 remaining index.

16. liquid laundry detergent as claimed in claim 15, described washing composition comprise as each is described or by one or more microcapsule as method preparation as described in the claim 9,10 or 11 in the claim 1 to 8.

17. a method that cleans dirty article or substrate, described method comprise described article or substrate are contacted with the aqueous solution that comprises as each described liquid detergent composition in the claim 13 to 16.

18. one kind under the hard water condition as described in the claim 16 in washing machine the method for cleaning clothing, described method comprises that with described clothing and hardness be that the water of 2mmol/L contacts and adds as the described liquid detergent composition of claim 13 to 16 at least.

19. one kind under the hard water condition in washing machine cleaning clothing and on clean clothing, do not stay the method for visible resistates, said method comprising the steps of: described clothing and hardness are contacted for the water of 2mmol/L at least and add liquid washing agent, described liquid washing agent comprises by about 0.3% to 3% the microcapsule of described liquid washing agent weight, described microcapsule have core and polymeric polyanion-polycation composite shell, and wherein said liquid washing agent provides about 10ppm washing assistant to about 2000ppm in washing liq.