CN111803427A

CN111803427A - Oil-in-water type cosmetic composition and preparation method thereof

Info

Publication number: CN111803427A
Application number: CN202010715312.6A
Authority: CN
Inventors: 吴洪庆; 彭燕辉; 罗巧玲
Original assignee: Peng Shi Huizhou Industrial Development Co ltd
Current assignee: Peng Shi Huizhou Industrial Development Co ltd
Priority date: 2020-07-23
Filing date: 2020-07-23
Publication date: 2020-10-23
Anticipated expiration: 2040-07-23
Also published as: CN111803427B

Abstract

The invention relates to the technical field of cosmetics, in particular to an oil-in-water type cosmetic composition and a preparation method thereof, wherein the composition comprises the following components in parts by weight: 0.5-6 parts of nonionic surfactant, 0.05-4 parts of oily component, 1-4 parts of water phase component A, 1-4 parts of water-soluble polymer and 40-80 parts of water phase component B, wherein the HLB value of the nonionic surfactant is 10-16.

Description

Oil-in-water type cosmetic composition and preparation method thereof

Technical Field

The invention relates to the technical field of cosmetics, in particular to an oil-in-water type cosmetic composition and a preparation method thereof.

Background

The cosmetic is a chemical industrial product or a fine chemical product which is applied to any part of the surface of a human body, such as skin, hair, nails, lips and teeth, by smearing, spraying or the like, so as to achieve the purposes of cleaning, maintaining, beautifying, decorating and changing the appearance, or correcting the odor of the human body and keeping a good state. The toning lotion as a water-based cosmetic is easy to absorb, has a clear and moist skin feel and is popular with most consumers. However, the moisturizing lotion is weak in moisturizing feeling, and part of consumers do not want to apply greasy cream because the skin is too dry, so that the development of the moisturizing lotion containing the oil is urgently needed.

Generally, the lotion is rarely added with oil, and the lotion can be emulsion after the lotion is added with the oil. Emulsions generally refer to dispersions in which one liquid is dispersed into another liquid, which are immiscible with each other, and the basic types of emulsions include two major types, oil-in-water (O/W) and water-in-oil (W/O). The emulsion is a thermodynamically unstable system with increased interface energy, and unstable phenomena such as floating, sedimentation, flocculation and the like occur after long-term placement, so that the emulsion is layered, and the skin feel and the efficacy of the emulsion are reduced.

The D-Phase Emulsification (D-Phase Emulsification) is a novel Emulsification technology proposed by Sagitani in 1980. Phase D (also called surfactant phase) is a phase state in which the aqueous phase and the oil phase are separated by a surfactant monolayer molecular film.

The polyol-containing surfactant solution is mixed with a sufficient amount of oil phase to produce a translucent or transparent phase D gel. The interfacial tension of the D phase gel is close to 0, and the D phase gel is easy to generate phase transformation to form oil-in-water or water-in-oil nano emulsion.

The nano emulsion is an emulsion with the droplet size of 50-500nm, is transparent or semitransparent in appearance, has better dynamic stability, and is not easy to float, settle and flocculate. The nanoemulsions have a low oil/water interfacial tension and good wetting, spreading, deposition and permeability properties. The nano emulsion has small droplet size and large specific surface area, and is favorable for the transmission and transdermal absorption of active substances. Meanwhile, the surfactant content is low, and the irritation to the skin is small. Therefore, the nano emulsion has good application prospect in the field of cosmetics.

At present, the nano-scale oil-in-water type toning lotion in the market and related researches are few, and the Chinese patent application CN 110538079A in the prior art discloses moisturizing and moisturizing toning lotion prepared by a D-phase emulsification method and a preparation method thereof, wherein the toning lotion comprises an oily component, a nonionic surfactant, polyhydric alcohol, an additive and water. The preparation method comprises the following steps: 1) mixing polyalcohol and nonionic surfactant according to a certain proportion, heating and stirring to 75-83 ℃ to obtain uniformly dispersed mixed components; 2) heating the oily component to 75-83 deg.C and stirring to obtain oil phase component; 3) adding the oil phase component obtained in the step 2) into the mixed component obtained in the step 1), uniformly stirring at 75-83 ℃ and 300-500rpm to obtain a gel phase component, and preserving heat; 4) heating water to 75-83 ℃, slowly adding the components in the gel phase obtained in the step 3) under the stirring of 300-; 5) and cooling the homogenized sample to 35-50 ℃ under stirring, adding an additive, mixing uniformly, and cooling to room temperature to obtain the moisturizing lotion prepared by the D-phase emulsification method. The lotion applied by the patent improves the water moistening degree and stability to a certain extent, but the process is complicated, and relates to a multi-step high-temperature and homogenizing process, and the stability and moistening effect are required to be further improved.

Chinese patent application CN108635252A discloses an emulsified cosmetic water and a preparation method thereof, wherein the emulsified cosmetic water comprises an A phase, a B phase, a C phase, a D phase, an E phase, an F phase, a G phase and an H phase, and although the stability and the moisturizing property are improved to a certain extent, the raw materials are multi-phase components, the problems of complex process and multi-step high temperature exist, and the stability and the moisturizing property are required to be further improved.

In summary, the current oil-in-water type cosmetics have the advantages of tedious process, few product types and wide development prospect in the market.

Therefore, it is very necessary to develop an oil-in-water type cosmetic composition and a method for preparing the same, which can solve the above-mentioned problems.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide an oil-in-water type cosmetic composition with good moistening property and stability and simple preparation process and a preparation method thereof.

The invention is realized by the following technical scheme:

an oil-in-water cosmetic composition, which comprises the following components in parts by weight: 0.5-6 parts of nonionic surfactant, 0.05-4 parts of oily component, 1-4 parts of water phase component A, 1-4 parts of water-soluble polymer and 40-80 parts of water phase component B.

Preferably, the composition comprises the following components in parts by weight: 2-4 parts of nonionic surfactant, 0.1-2 parts of oily component, 2-3 parts of water phase component A, 2-3 parts of water-soluble polymer and 45-75 parts of water phase component B.

Preferably, the nonionic surfactant has an HLB value of 10 to 16.

More preferably, the nonionic surfactant has an HLB value of 12 to 14.

Preferably, the nonionic surfactant includes at least two of fatty alcohol polyoxyethylene ethers, polyoxyethylene hydrogenated castor oil, and sorbitan fatty acid esters.

More preferably, the nonionic surfactant is two or three of laureth-11, laureth-13, PEG-40 hydrogenated castor oil and sorbitan oleate.

More preferably, the non-ionic surfactant is a mixture of PEG-40 hydrogenated castor oil and sorbitan oleate.

When the PEG-40 hydrogenated castor oil and the sorbitan oleate are used together, the HLB value of the mixture is close to the requirement of D-phase emulsification, the emulsification capacity is obviously improved, and the prepared product is more stable.

More preferably, the mass ratio of the PEG-40 hydrogenated castor oil to the sorbitan oleate is 8-10: 2-4.

Preferably, the oily component comprises any one or more of caprylic/capric triglyceride, cyclopentadimethylsiloxane, mineral oil, squalane and tocopheryl acetate.

More preferably, the oily component is a mixture of caprylic/capric triglyceride and squalane.

Caprylic/capric triglyceride spreads well but is too greasy. Squalane has poor spreadability, but is light, thin and refreshing. After the two are mixed together, the coating is easy to spread and apply, is fresh and moist, and has obviously improved effect.

More preferably, the mass ratio of caprylic/capric triglyceride to squalane is 2-4: 1.

Preferably, the aqueous phase component a comprises a mixture of water and one or more of glycerol, propylene glycol and butylene glycol;

more preferably, the aqueous phase component a is a mixture of butylene glycol and water.

More preferably, the mass ratio of the butanediol to the water is 2-4: 1.

Preferably, the water-soluble polymer comprises any one or more of polyacrylic acid, sodium polyacrylate, polyacrylate cross-linked polymer, hydrogenated starch hydrolysate, sodium alginate, sclerotium rolfsii and cellulose.

More preferably, the water-soluble polymer is a mixture of a polyacrylate cross-linked polymer and sodium alginate.

More preferably, the mass ratio of the polyacrylate cross-linked polymer to the sodium alginate is 2-3: 1.

Preferably, the aqueous phase component B is prepared by dissolving one or more of glycerol, propylene glycol, butylene glycol, dipropylene glycol, sorbitol, sucrose and PEG in water.

The present invention also relates to a method for preparing the above oil-in-water type cosmetic composition, comprising the steps of:

(1) weighing the water phase component A and the nonionic surfactant, mixing and stirring to obtain a mixture A;

(2) adding the oily component into the mixture A, and continuously stirring to obtain a D-phase gel;

(3) and adding the water phase component B and the water-soluble polymer into the D-phase gel, and uniformly mixing to obtain the D-phase gel.

Preferably, step (1) comprises the steps of: weighing the water phase component B and the nonionic surfactant, mixing, heating at 50-70 ℃ until the components are dissolved uniformly, stirring and cooling to room temperature to obtain a mixture A.

More preferably, the mixing is carried out at a shear rate of 100-.

Preferably, the rate of addition in step (2) is from 10 to 40%/min.

The term "10-40%/min" means that 10-40% by weight of the oily component is added per minute.

Preferably, the mixing in step (3) is carried out at a shear rate of 100-600 rpm.

More preferably, the preparation method comprises the following steps:

(1) weighing the water phase component A and the nonionic surfactant, mixing at a shear speed of 100-600rpm, heating to 50-70 ℃ until the components are dissolved uniformly, stirring and cooling to room temperature to obtain a mixture A;

(2) adding the oily component into the mixture A at the rate of 10-40%/min, and continuously stirring to obtain D-phase gel;

(3) adding the water phase component B and the water-soluble polymer into the D-phase gel, and uniformly mixing at a shear speed of 100-600 rpm.

Preferably, the oil-in-water cosmetic composition further comprises an active.

More preferably, the composition also comprises 0.001 to 15 parts of active substances by weight.

More preferably, the composition also comprises 0.01-1 part of active matter by weight.

More preferably, the active comprises at least one of niacinamide, ascorbyl palmitate, purslane extract, glycosyl trehalose, oat extract, raspberry fruit extract, prickly pear stem extract, agave extract, and nymphaea alba extract.

More preferably, the active is a mixture of niacinamide, glycosyl trehalose and oat extract.

The nicotinamide has a whitening effect, the glycosyl trehalose has a moisturizing effect, the oat extract has a soothing effect, and the three are mixed together for use, so that various effects are increased, and a synergistic enhancement effect can be achieved.

More preferably, the mass ratio of the nicotinamide, the glycosyl trehalose and the oat extract is 1-2:1: 1-2.

(1) weighing the water phase component A and the nonionic surfactant, and mixing and stirring to obtain a mixture A;

(3) and adding the water phase component B, the active substance and the water-soluble polymer into the D-phase gel, and uniformly mixing to obtain the D-phase gel.

More preferably, the mixing is carried out at a shear rate of 100-.

Preferably, the rate of addition in step (2) is from 10 to 40%/min.

More preferably, the preparation method comprises the following steps:

(1) weighing the water phase component B and the nonionic surfactant, mixing at a shear speed of 100-600rpm, heating to 50-70 ℃ until the components are dissolved uniformly, stirring and cooling to room temperature to obtain a mixture A;

(3) adding the water phase component B, the active substance and the water-soluble polymer into the D-phase gel, and uniformly mixing at a shear speed of 100-600rpm to obtain the D-phase gel.

The invention has the beneficial effects that:

the invention uses the nonionic surfactant with the HLB value of 8-16 to form certain steric hindrance together with the water-soluble polymer, thereby reducing the aggregation of oil drops, improving the stability of the product, solving the product quality problems of floating oil, even layering and the like in common oil-in-water type cosmetics, prolonging the shelf life of the product, improving the use feeling of consumers and ensuring the benefits of the consumers. Meanwhile, the composition of the nonionic surfactant is optimized, so that the oily component can be better dispersed in water, and the stability of the product is further improved.

According to the invention, by optimizing the composition of the oily component, the water-soluble polymer and the water-phase component B, and the synergistic effect of the components, the stability of the product is further improved, the using effects of the product such as the moistening property, the spreadability and the refreshing property are improved, and the requirements of consumers on refreshing and moistening skin, no stickiness and the like are met.

The invention further meets the requirements of whitening, brightening, relieving and the like of consumers by adding the active substances, and improves the stability and the moistening performance of the product. Especially, when the active matter is a mixture of nicotinamide, glycosyl trehalose and oat extract, the synergistic effect of the three is the best.

The invention has simple preparation process, can prepare and store each phase in advance, can be mixed uniformly when in use, and has convenient operation. The emulsion prepared by the invention has the particle size within the range of 80-500nm and better stability. The common astringent can reduce the dispersibility, stability and moistening property after being added with oil. The lotion prepared by the invention has the advantages that the grease is uniformly dispersed in the lotion, the particle size is small, and the grease can effectively permeate and moisten the skin.

The invention is mainly prepared at normal temperature, does not need a homogenization step, and obviously reduces energy loss and operation time.

Detailed Description

The invention will be further described with reference to specific embodiments, and the advantages and features of the invention will become apparent as the description proceeds. These examples are illustrative only and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.

The component names represented by the letters in the following examples are respectively: and (2) component A: nonionic surfactant, component B: oily component, component C: water phase component A, component D: water-soluble polymer, component E: water phase component B, component F: an active.

Example 1

Table 1 example 1 ingredient table

The preparation method of the oil-in-water type cosmetic composition comprises the following steps:

(1) weighing the water phase component A and a nonionic surfactant (the mixing HLB value is 14), mixing at a shear speed of 200rpm, heating to 50 ℃ until the components are dissolved uniformly, stirring, and cooling to room temperature to obtain a mixture A;

(2) weighing the oil phase components. Slowly adding the oily component into the mixture A at the normal temperature, wherein the adding speed is 10%/min, and continuously stirring at the shearing speed of 200rpm to obtain D-phase gel; the "10%/min" means that 10 wt% of the oily component is added per minute.

(3) And at normal temperature, sequentially adding the water phase component B, the active substance and the water-soluble polymer into the D-phase gel, and uniformly mixing at a shearing speed of 200rpm to obtain the D-phase gel.

Example 2

Table 2 example 2 ingredient table

(1) weighing the water phase component A and a nonionic surfactant (the mixing HLB value is 12), mixing at a shear speed of 100rpm, heating to 50 ℃ until the components are dissolved uniformly, stirring, and cooling to room temperature to obtain a mixture A;

(2) weighing the oil phase components. Slowly adding the oily component into the mixture A at the normal temperature, wherein the adding speed is 10%/min, and continuously stirring at the shearing speed of 100rpm to obtain D-phase gel; the "10%/min" means that 10 wt% of the oily component is added per minute.

(3) And at normal temperature, sequentially adding the water phase component B, the active substance and the water-soluble polymer into the D-phase gel, and uniformly mixing at a shear speed of 100rpm to obtain the D-phase gel.

Example 3

Table 3 example 3 ingredient table

(1) weighing the water phase component A and a nonionic surfactant (the mixing HLB value is 16), mixing at a shear speed of 600rpm, heating to 70 ℃ until the components are dissolved uniformly, stirring, and cooling to room temperature to obtain a mixture A;

(2) weighing the oil phase components. Slowly adding the oily component into the mixture A at the normal temperature, wherein the adding speed is 40%/min, and continuously stirring at the shearing speed of 600rpm to obtain D-phase gel; the "40%/min" means that 40 wt% of the oily component is added per minute.

(3) And at normal temperature, sequentially adding the water phase component B, the active substance and the water-soluble polymer into the D-phase gel, and uniformly mixing at a shear speed of 600rpm to obtain the D-phase gel.

Example 4

Table 4 example 4 ingredients table

(1) weighing the water phase component A and a nonionic surfactant (the mixing HLB value is 14), mixing at a shear speed of 350rpm, heating to 60 ℃ until the components are dissolved uniformly, stirring, and cooling to room temperature to obtain a mixture A;

(2) weighing the oil phase components. Slowly adding the oily component into the mixture A at the normal temperature, wherein the adding speed is 25%/min, and continuously stirring at the shearing speed of 350rpm to obtain D-phase gel; the "25%/min" means that 25 wt% of the oily component is added per minute.

(3) And at normal temperature, sequentially adding the water phase component B, the active substance and the water-soluble polymer into the D-phase gel, and uniformly mixing at a shearing speed of 350rpm to obtain the D-phase gel.

Example 5

Table 5 example 5 ingredient table

(1) weighing the water phase component A and a nonionic surfactant (the mixing HLB value is 16), mixing at a shear speed of 300rpm, heating to 60 ℃ until the components are dissolved uniformly, stirring, and cooling to room temperature to obtain a mixture A;

(2) weighing the oil phase components. Slowly adding the oily component into the mixture A at the normal temperature, wherein the adding speed is 15%/min, and continuously stirring at the shearing speed of 300rpm to obtain D-phase gel; the term "15%/min" means that 15 wt% of the oily component is added per minute.

(3) And at normal temperature, sequentially adding the water phase component B, the active substance and the water-soluble polymer into the D-phase gel, and uniformly mixing at a shearing speed of 300rpm to obtain the D-phase gel.

Example 6

Table 6 example 6 ingredient table

(3) And at normal temperature, sequentially adding the water phase component B and the water-soluble polymer into the D-phase gel, and uniformly mixing at a shearing speed of 350rpm to obtain the D-phase gel.

Example 7

Table 7 example 7 ingredients table

Example 8

The difference from example 4 is only that component F is used in a constant amount, the composition is different, and the other conditions are the same, as shown in Table 8.

Table 8 example 8 component F composition

Comparative example 1

TABLE 9 comparative example 1 ingredient Table

The preparation method of the oil-in-water type cosmetic composition is the same as that of example 7.

Comparative example 2

TABLE 10 comparative example 2 ingredient Table

Comparative example 3

TABLE 11 comparative example 3 ingredient table

Comparative example 4

TABLE 12 comparative example 4 ingredients Table

Comparative example 5

TABLE 13 comparative example 5 ingredient Table

Comparative example 6

TABLE 14 comparative example 6 ingredients Table

Comparative example 7

TABLE 15 comparative example 7 ingredients Table

Comparative example 8

TABLE 16 comparative example 8 ingredients Table

Comparative example 9

TABLE 17 comparative example 9 ingredients Table

(1) weighing the water phase component A and a nonionic surfactant (the mixing HLB value is 8), mixing at a shear speed of 350rpm, heating to 60 ℃ until the components are dissolved uniformly, stirring, and cooling to room temperature to obtain a mixture A;

(2) weighing the oil phase components. Slowly adding the oily component into the mixture A at the normal temperature, wherein the adding speed is 25%/min, and continuously stirring at the shearing speed of 350rpm to obtain D-phase gel;

Examples of effects

The invention mainly considers the stability and the moistening performance of the product, observes whether the appearance of the product changes (color tone, layering, peculiar smell and the like) and measures the water content after the product is smeared on the skin, and concretely comprises the following steps:

1. high temperature, Low temperature storage stability test

In order to ensure the performance of the product in the processes of storage and use, avoid physicochemical change and phenomena of floating oil, emulsion breaking and the like which influence the trial use of consumers, the high-temperature and low-temperature storage stability test of the product can be carried out. The laboratory high-temperature and low-temperature storage stability test is carried out by adopting the following method:

(1) placing in a 50 deg.C electric heating constant temperature incubator for 90 days, and observing after recovering room temperature;

(2) changing back and forth between-15 ℃ and 50 ℃ within 72 hours, wherein the temperature rising speed is 0.625 ℃ per hour, the temperature reducing speed is also 0.625 ℃ per hour, repeating the operation for 6 cycles, and observing after the room temperature is recovered;

(3) the mixture was placed in a-15 ℃ refrigerator for 90 days, and then returned to room temperature. The results are shown in Table 18. Wherein the effect data of example 8 are the effect data of groups 8-1 to 8-5 of example 8, and five groups are all homogeneous emulsions.

TABLE 18 high and Low temperature storage stability test results

2. Test of stability at room temperature

The test method comprises the following steps: after being placed at normal temperature for 1-3 weeks, the state and the using effect are evaluated. The results are shown in Table 19. Wherein the effect data of example 8 are the effect data of groups 8-1 to 8-5 in example 8, and five groups are all uniform emulsions, which are fast to absorb and have fresh and moist skin feel.

TABLE 19 Room temperature shelf stability test

3. Test of moistening Property of product

The test method comprises the following steps: after the subjects cleaned their faces, they were rested in a constant environment for 3 minutes and then tested using a moisture content tester (Corneometer CM825, Courage & Khazaka, Germany). The average value is taken by 3 times of continuous tests, and the higher the parameter value, the higher the water content of the stratum corneum of the skin is. The test specimens were then evenly smeared with latex gloves at 2mg per square centimeter and the time was started. Skin moisture content results are shown in table 20.

TABLE 20 product wettability test

As can be seen from the data results in Table 20, the product prepared by the phase D emulsification technique in the examples of the present invention has good moisture retention, and can effectively moisturize the skin and prevent the skin from being in a long-term dry state.

The above detailed description is specific to one possible embodiment of the present invention, and the embodiment is not intended to limit the scope of the present invention, and all equivalent implementations or modifications without departing from the scope of the present invention should be included in the technical scope of the present invention.

Claims

1. An oil-in-water cosmetic composition, characterized in that the composition comprises the following components in parts by weight: 0.5-6 parts of nonionic surfactant, 0.05-4 parts of oily component, 1-4 parts of water phase component A, 1-4 parts of water-soluble polymer and 40-80 parts of water phase component B, wherein the HLB value of the nonionic surfactant is 10-16.

2. The oil-in-water cosmetic composition according to claim 1, characterized in that it comprises the following components in parts by weight: 2-4 parts of nonionic surfactant, 0.1-2 parts of oily component, 2-3 parts of water phase component A, 2-3 parts of water-soluble polymer and 45-75 parts of water phase component B, wherein the HLB value of the nonionic surfactant is 12-14.

3. The oil-in-water cosmetic composition according to claim 1, wherein the nonionic surfactant comprises at least two of fatty alcohol polyoxyethylene ethers, polyoxyethylene hydrogenated castor oil, and sorbitan fatty acid esters, preferably two or three of laureth-11, laureth-13, PEG-40 hydrogenated castor oil, and sorbitan oleate; the oily component comprises any one or more of caprylic/capric triglyceride, cyclopentadimethylsiloxane, mineral oil, squalane and tocopheryl acetate; the water phase component A comprises a mixture of one or more of glycerol, propylene glycol and butanediol and water; the water-soluble polymer comprises any one or more of polyacrylic acid, sodium polyacrylate, polyacrylate cross-linked polymer, hydrogenated starch hydrolysate, sodium alginate, sclerotium rolfsii gum and cellulose; the water phase component B is prepared by dissolving one or more of glycerol, propylene glycol, butanediol, dipropylene glycol, sorbitol, sucrose and PEG in water.

4. The oil-in-water cosmetic composition according to claim 3, wherein the non-ionic surfactant is a mixture of PEG-40 hydrogenated castor oil and sorbitan oleate; the oily component is a mixture of caprylic/capric triglyceride and squalane; the water-soluble polymer is a mixture of polyacrylate cross-linked polymer and sodium alginate; the aqueous phase component A is a mixture of butanediol and water.

5. The oil-in-water cosmetic composition according to claim 4, wherein the mass ratio of the PEG-40 hydrogenated castor oil to the sorbitan oleate is 8-10: 2-4; the mass ratio of the caprylic/capric triglyceride to the squalane is 2-4: 1; the mass ratio of the polyacrylate cross-linked polymer to the sodium alginate is 2-3: 1; the mass ratio of butanediol to water in the water phase component A is 2-4: 1.

6. The oil-in-water cosmetic composition according to any one of claims 1 to 5, further comprising 0.001 to 15 parts by weight of an active comprising at least one of niacinamide, ascorbyl palmitate, purslane extract, glycosyl trehalose, oat extract, raspberry fruit extract, prickly pear stem extract, agave extract and nymphaea alba extract.

7. The oil-in-water cosmetic composition according to claim 6, wherein the active is 0.01-1 part, and the active is a mixture of niacinamide, glycosyl trehalose and oat extract.

8. The oil-in-water cosmetic composition according to claim 7, wherein the mass ratio of niacinamide, glycosyl trehalose and oat extract is 1-2:1: 1-2.

9. The process for the preparation of the oil-in-water cosmetic composition according to any one of claims 1 to 8, characterized in that it comprises the steps of:

(3) and adding the water phase component B, the active substance and the water-soluble polymer into the D-phase gel to obtain the D-phase gel.

10. The method of claim 9, comprising the steps of: