RU2730990C1 - Method of stabilizing pigments in colored photo-crosslinkable gel polish - Google Patents

Abstract

FIELD: meeting human vital needs; chemistry.

SUBSTANCE: invention relates to production of gel compositions for nail extensions and decoration. Method of stabilizing pigments in colored photo-crosslinkable gel polish involves mixing, during continuous stirring, a polyurethane composition and a coloring colorant in a high-speed dissolver with a disc-type mixer at rate of 1,000–5,000 rpm for at least 30 minutes while maintaining temperature of the mixture in the dissolver is not higher than +55 °C. Weight ratio of polyurethane composition and colorantol makes 100:5–50 wt%, and weight ratio of colorless base and pigment pastes in colorant is 100:50–200 wt%, and further deaeration of mixture is carried out for at least 30 minutes in vacuum chamber with pressure of -0.05…-0.5 MPa and using low-speed mixer, rotating at rate of 40–80 rpm.

EFFECT: longer storage life of the gel polish without delamination of the base and the pigment, id est improved consumer properties of the product.

1 cl, 3 tbl

Description

The invention relates to a technology for the manufacture of gel compositions for nail extension for protective and decorative purposes.

Gel polish (shellac) is a hybrid of nail polish and a special modeling gel with high strength, it is easy to apply and cures quickly under a UV lamp. To create a wide range of decorative gel varnishes, a colorless base is mixed with various coloring additives, pigments, pigment pastes, glitters, etc.

In the field of nail varnishes, cosmetic compositions are known that are used to apply a coating layer to a nail, and then the specified layer is exposed to light radiation, causing polymerization reactions and / or cross-linking in the specified layer, which usually leads to the formation of crosslinked polymer networks. Such photocrosslinkable compositions based on crosslinkable (meth) acrylate compounds are suitable for obtaining satisfactory stability of the coating layer applied to the nail.

The closest in technical essence among the known methods is a method for the manufacture of gel varnish for nails according to the application for the grant of a patent for invention RU No. 2016134990 "GEL-varnish for nails, as well as a method for its manufacture and use", where the applicant ZHEN Lijuan (US) proposed a method for the manufacture of gel varnish for nails (see clause 7 of the claims), including the stages:

- dissolving aliphatic urethane acrylate and polymeric acrylate oligomer in a monomeric diluent by heating and stirring them to form a first mixture;

- mixing and stirring the photoinitiator together with the first mixture to form a second mixture;

- adding and mixing the coloring agent with the second mixture to form the finished product in the form of gel nail polish.

However, the described method of making gel polish for nails according to application No. 2016134990 does not allow obtaining a gel polish that is stable during storage, that is, a gel polish made in this way will have a violation of color stability during storage, while retaining color without delamination for decorative gel polish, is the most important characteristic. In addition, in the described manufacturing method, the preparation of gel polish is represented by mixing ready-made polymers, diluents, therefore, the properties of the resulting product may differ depending on the purchased batch of oligomers.

To stabilize pigment pastes, special additives are usually used: dispersants, wetting agents, anti-sedimentation modifiers.

The claimed method makes it possible to obtain a high-quality color gel polish without resorting to the introduction of third-party modifiers, which is important, since some added additives stabilize the pigment by changing the surface tension and viscosity, which has a negative effect on the physical properties of the finished product, which further complicates the application process gel polishes on the nail plate.

The technical problem lies in the development of a method for obtaining a high-quality gel polish without the use of special additives, that is, a gel polish with high storage stability without stratification into a base and pigment.

The technical result consists in increasing the shelf life of the gel polish without stratification into the base and pigment, that is, improving consumer properties.

The reason for the delamination of gel polish is the air microbubbles present in the viscous medium of the gel polish, which, during storage, come to the surface, carrying with them the transparent base of the gel polish, which leads to delamination into the base and the pigment, that is, to a violation of color stability and viscosity of the finished product. It was found that the violation of the stability of color gel polish usually occurs after 1-3 weeks of storage.

To increase the shelf life of gel polish without delamination, it is necessary to reduce the amount of dispersed air in the volume of the gel polish before packing the finished product, that is, to deaerate it, which is carried out in a vacuum chamber.

In the claimed method, in order to more effectively reduce the concentration of dispersed air bubbles, the vacuum chamber (taking into account the specifics of the processed product) was supplemented with a slow-speed stirrer, the use of which, together with the evacuation process, made it possible to successfully deaerate the mixture to almost complete removal of air bubbles, and without the formation of foam, since continuous stirring at low speeds contributes to the collapse of air bubbles concentrating on the surface during deaeration and prevents the creation of conditions for gel varnish delamination.

With continuous stirring of the mixture in a vacuum chamber at low speeds, air microbubbles present in a viscous medium gradually leave its volume until complete removal. Thus, equipping the vacuum chamber with a low-speed stirrer made it possible to obtain a high-quality gel polish with an increased shelf life, that is, to improve the consumer properties of the product.

When deaerating a colored gel polish without using a slow-speed stirrer, a significant layer of foam is concentrated on the surface, since the substance of the gel polish is viscous, and additional external influence is required to collapse the air bubbles.

The author of the invention selected such parameters of the method that made it possible to obtain a stable color gel varnish.

The technical problem is solved, and the technical result is achieved by the fact that the method for making gel polish includes the primary mixing of the components in a dissolver at a speed of 1000-5000 rpm for at least 30 minutes while maintaining the temperature of the mixture at a level of up to + 55 ° C, while the mass ratio the polyurethane composition and the colored colorant is 100: 5-50 (the ratio of the colorless base and pigment pastes in the colorant is 100: 50-200 wt%), and the mixture is further mixed in a vacuum chamber with a pressure of 0.05 ÷ -0, 5 MPa for at least 30 minutes using a slow-speed stirrer rotating at a speed of 40-80 rpm.

This process stabilizes the color composition and prevents delamination.

The causal relationship between the distinctive features of the invention and the technical problem to be solved is explained as follows.

Tinting is the process of adding colorants to a colorless base to give it the desired shade. Microbubbles of air are initially present in the colorless base, since the synthesis is carried out under continuous mechanical action - stirring, during which air is drawn into the product. Further, during the tinting process, air also enters the gel polish, increasing the concentration of microbubbles, which are hardly noticeable to the naked eye, but the presence of which is the main factor affecting the stability of the product.

In the process of tinting, the mixture heats up due to the high speed of mutual friction of the molecules, which is created by the high speed of rotation of the dissolver cutter, which sets the total volume of the mixture in motion, and the mixture heats up uncontrollably. To prevent thermal degradation of the acrylic-polyurethane composition, it is required to control and stabilize the temperature, which is achieved by cooling - by supplying a coolant through the coil or jacket of the dissolver tank cooling. Therefore, in the present invention, during the homogenization of gel varnish and pigments, the temperature is maintained at a level of up to + 55ºC.

The viscosity of the deaerated gel varnish obtained by the claimed method and the gel varnish containing air microbubbles in its volume have different viscosities, which affects the quality of the coating on the nail plate. The deaerated color acrylic polyurethane composition produced by the claimed method has a viscosity of 10980-11025 mPa * s, and a gel polish with air in volume - 11570-12990 mPa * s. The technology of applying gel varnishes with a higher viscosity to the nail plate is more complex and requires additional skills from the master who applies the application.

The presence of air microbubbles in the finished gel polish also negatively affects the quality of the coating, since during the polymerization process under a UV lamp, air moves to the surface with simultaneous curing of the composition, as a result of which irregularities are formed (so-called "craters" and defects caused by "boiling »Compositions).

Applying the claimed method for stabilizing pigments in color photocrosslinked gel varnishes, we obtain a gel varnish with stable performance over a long shelf life.

The technical essence of the claimed method is illustrated by examples of specific implementation.

Examples of specific implementation of the claimed method

First, a ready-made colorless acrylic polyurethane composition, the raw material composition of which is given in Table No. 1, was loaded into a high-speed dissolver with a disc milling mixer (at a filling height of 2 cutter diameters), and a colored colorant was introduced with continuous stirring, and as pigment pastes (see table No. 2), pigment pastes of the Air group of companies (Pbk-11) and the Arichemie company (R-30011-1, G-30016-1, O-30017-1, R-30014-1) were used.

The mass ratio of the colorless acrylic polyurethane composition and the colored colorant was 10: 1 wt%, then the mixture was stirred in a dissolver at a speed of 2000 rpm for 30 minutes.

In the examples described, the color colorant was 10% by weight of the total amount of the tinted composition. A colorant is a mixture of a colorless base and pigment pastes previously distributed and soaked in it in a ratio of 100: 80-100. Thus, the total amount of pigment pastes was 3.7 - 4.5% by weight of the total amount of the mixture.

Table No. 1

P / p No. Raw material composition of colorless acrylic polyurethane composition Content,
wt% 1 Aromatic isocyanate 10-60 2 Methacrylic acid ester 5-40 3 Organometallic catalyst 0-5 4 Polybasic alcohol 5-40 five Aromatic alcohol 5-40 6 Photoinitiator isopropylthioxanthone 1-15

Table 2 shows examples of colorant formulations used, allowing to obtain gel polish, and the ratio of colorless acrylic polyurethane composition and colored pigment pastes is given for three variants of colorants used (K1, K2 and K3).

Table No. 2

The ratio of colorless acrylic polyurethane composition and color colorant P / p No. Colorant symbol Number of colorless acrylic polyurethane base, g Pigment paste Amount of pigment paste, g 1 K1 500 PBk-11 500 2 500 R-30011-1 500 3 K3 500 W-30001-1 196 G-30016-1 23 O-30017-1 168 R-30014-1 13

The process of mixing the components in a dissolver was carried out under strict adherence to the temperature regime, the temperature of the mixture was maintained in the temperature range from + 20 ° C to + 50 ° C, since an increase in temperature above + 55 ° C would affect the quality and stability of the resulting product and could lead to the destruction of the product and a change in shade ... The mixture was cooled by supplying a cooling liquid to the jacket of the dissolver vessel, after which the tinted acrylic polyurethane composition was loaded into a vacuum chamber with a pressure of -0.05 ÷ -0.5 MPa, equipped with a slow-speed stirrer rotating at a speed of 40-80 rpm, and deaeration was carried out by stirring the tinted acrylic-polyurethane composition for at least 30 minutes.

The advantage of the claimed method is that a high-quality gel polish is obtained only due to the selected operating modes and equipment, and without the use of any modifying additives that can change the viscosity, affect the speed and quality of polymerization, and impair the adhesion and elasticity of coatings.

The synthesized acrylic-polyurethane base was tinted, deaerated with and without a slow-speed stirrer, and then the duration of stable storage of the product (without delamination) was monitored. The observation results are presented in Table 3.

Table 3

P / p No. Symbol
colorants used Method for preparing gel polish Duration of stable storage of the product 1 K1 Mixing only in dissolver 13 days 2 K1 Using the claimed method More than 180 days 3 K2 Mixing only in dissolver 15 days 4 K2 Using the claimed method More than 180 days five K3 Mixing only in dissolver 13 days 6 K3 Using the claimed method More than 180 days

The results of comparing the time of stable storage of the finished product obtained by the claimed method with deaeration in a vacuum chamber with and without a slow-speed stirrer differ by more than an order of magnitude, which demonstrates the effectiveness of the declared vacuum modes with a slow-speed stirrer to stabilize pigments in viscous gel varnishes. The gel varnishes obtained by the claimed method show the stability of decorative and protective properties and are recommended for industrial production.

Claims (1)

A method for stabilizing pigments in color photocrosslinked gel varnishes, including loading a colorless acrylic-polyurethane composition into a high-speed dissolver, introducing a colored colorant , and the ratio of a colorless acrylic-polyurethane composition and a colored colorant is 100: 5-50 wt%, mixing the components in a dissolver and feeding the mixture into the vacuum chamber with a pressure of -0.05 ÷ -0.5 MPa, and the mixing of the components in the dissolver is carried out at a speed of 1000-5000 rpm for at least 30 minutes and while maintaining the temperature of the mixture at a level of up to + 55 ° C, after which the mixture is deaerated for at least 30 minutes in a vacuum chamber using a slow-speed stirrer rotating at a speed of 40-80 rpm, after which the finished product is fed for packing.