WO2011117164A1 - Water-soluble copolymers of 2-hydroxyethyl methacrylate and methacrylic acid - Google Patents

Abstract

Novel copolymers of 2-hydroxyethyl methacrylate (HEMA) and methacrylic acid (MAA) are described. The copolymers have a molar mass of less than 17 000 g/mol and, on the basis of their water solubility, and water absorption and release kinetics, are usable especially as humectants in cosmetic or dermatological formulations.

Description

 Water-soluble copolymers of 2-hydroxyethyl methacrylate and methacrylic acid

The invention describes novel copolymers of 2-hydroxyethyl methacrylate (HEMA) and methacrylic acid (MAS). The copolymers have a molecular weight of less than 17,000 g / mol and, owing to their water solubility, water supply and release kinetics, can be used in particular as moisturizers in cosmetic or dermatological preparations.

As water-soluble polymers, the person skilled in the art from a number of known polymers such as polyvinyl alcohol, gelatin, polyacrylic acid, sodium polyacrylates, methyl cellulose,

Select carboxymethylcellulose, polyvinylpyrrolidone, rubber and other crosslinkable polymers, and mixtures thereof.

 The disadvantage here is that these polymers act predominantly as thickeners for the water phase.

 Furthermore, the proportion of water-soluble polymers in cosmetic preparations is often limited to fractions of up to 1 or 2% by weight, since the polymers are soluble only to a small extent in water and, in addition, thicken the solution.

The disadvantage is that at these low proportions only little water absorption by the polymers is possible.

Another disadvantage of conventional polymers is their odor, caused by monomer residues and / or unsuitable for cosmetics solvents.

Known water-soluble polymers in cosmetics are, for example, carboxyvinyl polymers, as described in JP 2009040705, or crosslinked acrylic acid polymers or copolymers, which are commercially available as pemulen Tr-1, carbopols or carbomers.

US 6348199 and US 5306498 describe clear and stable gels for skin treatment, especially skin moisturization. The gels include polyglyceryl methacrylate, which are water-soluble and water-absorbent used as a moisturizer.

WO 20080871 19 describes styrene-acrylate diblock copolymers which are said to have skin-moisturizing properties.

The polyglyceryl (meth) acrylates are commercially available as homopolymers or copolymers with acrylic acid or methacrylic acid as Lubrajel® or Lubrasil®. The known polymers can generally be prepared by free-radical polymerization. Here, the use of the method of the polystyrene and

Polyvinyl chloride on polyacrylic acid, polyacrylamide to polyvinyl acetate. Different methods are used. In addition to the solution polymerization, emulsion, suspension and bulk polymerization are used.

EP 1 195394 describes the preparation of water-soluble copolymers by free-radically initiated polymerization of hydroxy-alkyl (meth) acrylates with optionally alkyl (meth) acrylates or vinyl esters and polyvinyl alcohol (PVA).

The copolymers thus prepared are used as coating or binder in

used pharmaceutical dosage forms.

 For the preparation of the copolymers hydroxy-alkyl (meth) acrylates, u.a. also HEMA, in the presence of PVA, both with the help of radical-forming initiators and by the action of high-energy radiation, including the action of higher energy

Electrons to be understood, polymerized. To initiate the

Emulsion polymerization radical initiators are used. The amounts used of initiator or initiator mixtures based on the monomer used are between 0.01 and 10 wt.%. Depending on the type of solvent used, both organic and inorganic peroxides or azo initiators such as azo-bis-isobutyronitrile, azo-bis (2-amidopropane) dihydrochloride or 2,2'-azobis (2-methylbutyronitrile) are suitable. , Examples of peroxidic initiators are dibenzoyl peroxide,

Diacetyl peroxide, succinyl peroxide, tert-butyl perpivalate, tert-butyl 2-ethylhexanoate, tert-butyl permalate, bis (tert-butyl peroxy) cyclohexane, tert-butyl peroxiisopropyl carbonate, tert-butyl peracetate, 2,2-bis - (tert-butylperoxy) -butane, dicumyl peroxide, di-tert-amyl peroxide, di-tert-butyl peroxide, p-menthane hydroperoxide, pinane hydroperoxide, cumene hydroperoxide, tert-butyl hydroperoxide, hydrogen peroxide and mixtures of the initiators mentioned. The radical emulsion polymerization according to EP 1 195394 finds

preferably in water with concomitant use of polyvinyl alcohol, in the presence of free-radical-forming polymerization initiators, optionally emulsifiers, optionally further protective colloids, optionally molecular weight regulators, optionally buffer systems and optionally subsequent pH adjustment by means of bases or acids. The copolymers are used as aqueous dispersions or aqueous

Solutions with a viscosity of less than 500 mPas or after removal of the

Water content, recovered as water-dispersible or water-soluble powder.

Since these copolymers should be usable in aqueous dispersions, no salts or electrolytes are suitable for this purpose. PVA is used according to EP 1 195394 as protective colloid. PVA prevents agglomeration of the non-water-soluble monomer droplets or polymer particles.

Since PVA is used in large quantities here, the polymers thus produced are additionally grafted with PVA, which apparently results in better film formation.

A disadvantage of the known poly (meth) acrylates and copolymers is their property often to swell in water to form gels and / or to act thickening.

Known from another field of technology - the contact lenses - methacrylic acid Coplymere, which are characterized by water absorption and oxygen permeation, such as in - production and characterization of hydrogels as

Kontaktlinsenmaterialien - Lecture on the occasion of the meeting of the Section "Macromolecular Chemistry" of the German Chemical Society on "Polymers and Water" in Bad Nauheim on 2 and 3 April 1984 - disclosed.

Since the late 1930s, contact lenses made of polymeric materials have been used on the human eye. At present, a variety of

Used contact lens materials, which consist of long-chain and interconnected more or less polar polymer chains. The currently available on the market contact lenses are divided by their material into two parent groups. The first group comprises the contact lenses, which consist of copolymers with ionic proportions. These copolymers are mostly made with constituents of methacrylic acid. However, the ionic components in a contact lens provide for some

unpleasant side effects, so that the abandonment of the ionic components, especially for long-term lenses was the logical step. This is how contact lenses made of materials that no longer contained ionic components were created. For this second large group were monomers such as N-vinyl-pyrrolidone (NVP), 2-hydroxyethyl methacrylate (HEMA) or

Glyceryl methacrylate (GLMA) used. The advantage of these polymer materials is that they are classified by the US Food and Drug Administration (FDA) and approved for human use. Furthermore, due to the industrial demand for o.g. Monomers given a cost-effective availability. Since the contact lenses today no longer consist only of a homopolymer, there are very extensive

Possible combinations for adjusting the moisture content of a lens.

In the meantime, contact lenses with ionic components, as well as those with exclusively nonionic components, achieve in vitro moisture contents of more than 50%. In addition to the required optical properties, the contact lens materials further have high gas permeabilities and very high moisture contents. The use of these contact lens polymers in cosmetic or dermatological

Dosage forms or formulations are, however, prohibited, since these lens polymers are not soluble in water but only swellable. The non-solubility is based primarily on it, since they are composed of long and highly interconnected polymer chains.

For use in cosmetics or other topically applied compositions, therefore, there was a desire for water-soluble polymers that are very soluble in water, have a high water absorption capacity and also show a high rehydration effect after application.

 It is also desirable to provide polymers which do not gel and / or thicken in water.

It is also desirable to expand the range of skin moisturisers to better meet the individual needs of consumers.

The invention includes copolymers of 2-hydroxyethyl methacrylate (HEMA) and

Methacrylic acid (MAS) (hereinafter referred to as HEMA-MAS copolymer) of structure (I)

With R1 and R2, the initiator radicals used in the preparation are characterized, which, depending on the particular initiator, in particular sulfate, hydrogen and / or

Hydroxidreste can represent.

Z ⁺ is a cationic residue.

The preferred methacrylic acid used is a neutralized methacrylic acid (MAS). That is, Z ⁺ then forms the cationic residue of the base used. Depending on which is neutralized with which bases, Z is preferably selected from H, Na, K, Ca, NH ₄ or other alkyl ammonium NR ₃ R ₄ R ₅ R ₆ with R ₃ -R ₆ = H, CH ₃ or

Preference is given to Z = Na, since methacrylic acid neutralized with sodium hydroxide solution or the copolymers forming exhibit better moisture absorption capacity.

In contrast to the copolymers shown in EP 1 195394, the

copolymers according to the invention due to the cationic radicals Z ⁺ and the initiator Ri, R ₂ polyelectrolytes which are and remain water-soluble.

Another difference is that copolymers of the invention do not have a

Emulsion polymerization are prepared and at a free-radical initiated

Polymerization in an aqueous solvent can be dispensed with the addition of protective colloids, emulsifiers or nonaqueous solvents.

The copolymers according to the invention are therefore obtainable in particular from

radical solution polymerization of 2-hydroxyethyl methacrylate (HEMA) and

Methacrylic acid (MAS). In the free-radical polymerization in solution, inorganic peroxy initiators are advantageously used. This is mainly due to the low cost and the excellent water solubility.

 When peroxodisulfates are used as initiator, it is advantageous to buffer the reaction solution to achieve the optimum radical yield.

The copolymers according to the invention are characterized by the coefficients n (MAS) and m (HEMA). According to the invention, the two coefficients n and m are in the range from m = 2 to m = 58, in particular m = 2 to m = 45, more preferably m = 4 to 12, very particularly preferably m is in the range from 5 to 10.

n is chosen in the range n = 8 to n = 105, in particular n = 8 to 75, in particular n is in the range 25 to 65, very particularly preferably n is in the range from 31 to 59.

The incorporation ratios of HEMA are preferably between 10 to 75 mole% to 25 mole% to 90 mole% of methacrylic acid (MAS). Mol.% Is here as well as below in each case based on the total number of moles of the monomers used.

The quantitative determination of the incorporation ratios of the two monomers 2-hydroxyethyl methacrylate (HEMA) and methacrylic acid (MAS) is carried out by means of ¹ H-NMR spectroscopy, as shown in Figure 1 - H spectrum of a HEMA-MAS copolymer. The signals of the methylene group of the 2-Hydroylethylreste (HEMA unit, b) and the

Methylene groups of the polymer chain (both HEMA and MA unit, d and f) can be uniquely assigned. On the basis of the resulting integration ratio of the two signals so the installation rate can be calculated.

The incorporation rate (expressed in mol.%) Of the methacrylates is calculated according to equation (1). The integral value of the signal of the methylene group b is calibrated to 1 at 3.7 ppm (two protons) and the corresponding integral value of the signals of the

Methylene groups d, f recorded at 1.6 - 2.0 ppm (four protons).

2 (1 - X) _ 2X + 2 (1 - X) χ ^~ 2I _a + 2I _b

2I _b

 X = incorporation rate of the methacrylate

(1-X) = incorporation rate of 2-hydroxyethyl acrylate

l _a = integral value of the signal of the methylene group of the HEMA unit b.

I = integral value of the signal of the methylene group of the polymer chains d, f (HEMA and MA unit)

The incorporation ratios of the two monomers surprisingly agree approximately with the ratios of the starting monomers used in the preparation. The advantage is that the two monomers can be used selectively in the desired ratio in order to achieve desired property of the polymer and remain after the polymerization no excess residual monomers, which must be additionally removed.

It is preferable to choose copolymers having an incorporation ratio HEMA-MAS in the range from 75 to 25% up to 10 to 90%. That Molar portions of HEMA are selected in the range of 10 to 75 mole percent and the proportions of MAS in the range of 25 to 90 mole percent. Particular preference is given to copolymers having an incorporation ratio HEMA-MAS in the range from 20% to 80%.

The molar mass of the copolymer is determined by the coefficients n and m, ie based on the molecular weight and installation ratios can be calculated n and m and conversely from the numbers n and m, the molecular weight. For example, the number average molecular weight HEMA-MAS is the preferred

Ratio of the two monomers (20:80) 3387 g / mol. The molar mass HEMA is 130.14 g / mol, the molar mass MAS is 86.09 g / mol.

The determination of the coefficients m and n then takes place via the incorporation ratio of HEMA 20% ie 3387 ^χ 0.2 = 677.4 g / mol divided by the molar mass of HEMA 677.4 +130.14 g / mol = 5.2.

The installation ratio of MAS 80% ie. 3387 ^χ 0.8 = 2709.6 g / mol divided by the

Molar mass of MAS 2709.6 +86.09 g / mol = 31.47

This results in m (HEMA) ~ 5 and n (MAS) ~ 31.

(without consideration of the radicals, as Ri, R ₂ or ^{* marked} in the formulas)

With an average molecular weight of the copolymer of HEMA-MAS of 6277 g / mol, the coefficients are m (HEMA) = 10 (9.6) and n (MAS) 58 (58.3).

The number average molecular weight of the copolymers is therefore advantageously below 17,000 g / mol, more preferably below 10,000 g / mol, in particular in the range from 3000 to 7000 g / mol.

By characterizing the copolymers according to the invention via the coefficients n and m, the incorporation ratios and / or molar mass, in particular in the ranges specified, it is ensured that the copolymers have their advantageous properties

Be able to fully exploit properties

Many methods are available for determining a molecular weight of a polymer. The most common methods for this are viscometry, light scattering or

Gel permeation chromatography. However, for most methods are

Reference substances required to deliver the desired results.

zahlenmittlere Molmasse All polymers investigated for their molecular weight are characterized by specific parameters. The literature contains mean values with which a polymer is characterized. The most important average is the number average molecular weight (M _n ):

number average molecular weight

 Number of macromolecules in the sample with exactly one repeating unit

Molecular weight i The number average molecular weight can be determined by colligative methods such as cryoscopy, membrane or vapor pressure osmometry and - if the number of

End groups per molecule is known - by end group determination.

As a further parameter, the weight average molecular weight (M _w ) is used:

M '■ weight-average molecular weight

 ". : Number of macromolecules in the sample with exactly one repeating units

M _i : molecular weight i

The weight average is obtained by methods that take into account the size and shape of a molecule in solution, e.g. static light scattering, small angle X-ray scattering and sedimentation equilibrium measurements.

 From two of these average molecular weights, one can calculate the polydispersity (P) of a polymer shown:

M "

P = polydispersity: weight-average molecular weight

] [["'■ Number average molecular weight

The polydispersity (P) is indicative of the nonuniformity of a polymer. The greater the polydispersity, the wider a polymer is distributed. In living polymerizations or polycondensations only very small polydispersities are achieved, while in free radical polymerizations significantly higher polydispersities are expected.

The kinetic chain length is defined as follows and allows approximate statements about the expected chain length of a polymer.

v = kinetic chain length

f = radical yield

k _t = rate constant of the termination reaction (disproportionation and termination) k _p = rate constant of the growth reaction

k _d = rate constant of the initiator decay

[M] = monomer concentration

[I] = initiator concentration

While the constants for initiator decay, termination and growth reaction substance resp. Environment constants are, can be achieved by changing the variables [M] and [I] different effects. Thus, a halving of the initiator concentration causes an increase in the chain length by about 40%. Halving the monomer concentration while maintaining the initiator concentration, however, causes a reduction in the chain length by about half. The kinetic chain length is therefore the root of the

Initiator concentration inversely proportional.

With these methods shown copolymers of the invention can be clearly characterized.

The 2-hydroxyethyl methacrylate-methacrylic acid copolymers of structure (I) are preferred according to the invention with

Initiatorreste R- ₁ , R ₂ or ^* selected from the group -H, -S0 ₄ , -OH,

cationic radicals Z ⁺ selected from H, Na, K, Ca, NH ₄ or

Alkylammonium compounds NR ₃ R ₄ R ₅ R ₆ with R ₃ -R ₆ HH, CH ₃ or C ₂ H _5,

 m (HEMA) = 2 to 58, advantageously in the range 2 to 45,

 - n (MAS) = 8 to 105, preferably in the range 8 to 75 or

M ^" <17,000 g / mol, preferably in the range <10,000 g / mol, and have advantageous

Molar parts HEMA in the range 10 to 75 mol% and MAS in the range 25 to 90 mol%,

- Installation ratios HEMA to MAS in the range of 10 mol.%: 90 mol.% To 75% to 25% on and

a polydispersity P <5. The preparation of the HEMA-MAS copolymers according to the invention is advantageously carried out according to the reaction equation:

 It is advantageous to proceed according to the following example production instructions.

 The amounts of 1.57 g (6.6 mmol) or 3.14 g (13.2 mmol) or 6.28 g, (26.4 mmol) of sodium peroxodisulfate (10.20 and 30 mol% based on the sum of the monomers used) and 0.55 g (6.5 mmol) or 1.1 g (13 mmol) or 2.2 g (26 mmol)

Sodium bicarbonate (ACROS) was dissolved in 50 mL of. Water is dissolved while stirring. Subsequently, the monomer mixtures were prepared from 4 mL (4.28 g, 33 mmol) HEMA, and 2.8 mL (2.84 g 33 mmol) in a ratio of 1: 1 by means of sodium hydroxide to pH 7 neutralized methacrylic acid. The neutralization of the methacrylic acid was carried out in water with the addition of saturated aqueous sodium hydroxide solution. The monomers were with the. Made up to 50 mL total volume and added dropwise over a period of 2 h to the temperature at 70 ° C initiator solution. After completing the addition, the

Reaction solution with a further 1 .1 g (4.4 mmol) of sodium peroxodisulfate and tempered for 2 h at 70 ° C. Subsequently, the reaction mixture was acidified to pH = 2 using dilute sulfuric acid. After removing the water, the residue was taken up in ethanol and stirred for 30 minutes at 80 ° C bath temperature to separate the copolymer from the salt residues. The suspension was then filtered and the filtrate was freed from ethanol under vacuum. After dissolving the polymer residue in the. Water, the solution was neutralized with sodium hydroxide solution to pH = 7 and the water removed. Table 1 shows the exemplary monomer feed levels

Tables 2 to 4 below represent examples of the yields of the copolymers thus prepared.

 Table 2:

Copolymer Poly-Uses Used Aspect Ratio / Number Average Dispersity Initiator Amount Yield Molar Mass M _n Mol - [%] on Σ

 [g / mol] monomers

HEMA: MAS 1529 (OAc) 4.92 20 crystalline 7.1 g / 99% 50:50

HEMA: MAS 1325 (OAc) 3.51 40 crystalline 7.0 g / 98% 50:50 Table 3:

The molar masses of the copolymers produced are also dependent on the amount of initiator used.

 The more initiator used, the more small polymers (shorter chain length) can be produced in the reaction. Halving the initiator concentration causes an increase in the chain length of about 40%.

Suitable initiators are water-soluble substances.

 For example, inorganic peroxides and water-soluble azo initiators from Wako (sodium, potassium and ammonium peroxodisulfates, 2,2'-azobis (2-methylpropionamidines) dihydrochlorides (V-50), 2,2'-azobis [2] have been used. (2-imidazolin-2-yl) propanes] dihydrochloride (VA-44) and 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-57)).

Natnumperoxidisulfat (NaPS) has been found to be most advantageous because the copolymers initiated by NaPS could absorb most moisture.

The initiators can advantageously be used in the range from 1 to 40 mol%, preferably in the range from 5 to 20 mol%, based on the total number of moles of the monomers used. In addition to the inorganic peroxodisulfates, it is also possible, for example, to use water-soluble azo initiators for the preparation of the copolymers. This is followed by only appropriate purification steps.

The Natnumperoxodisulfat (NaPS) initiator is preferably used in a preferred use range of 5 to 20 mol%, based on the total molar amount of the monomers used.

Table 5 below shows the influence of the different cations in the HEMA-MAS copolymer (20:80) on the water absorption capacity of the copolymers.

The number-average molar masses and polydispersity of the copolymer prepared by way of example are shown in Table 6 below.

Table 6: Determines molecular weights and polydispersities

Copolymer Obtained Poly Used Appearance / Number Average Dispersity Initiator Amount Yield on Molecular Weight M _n Mol - [%] Σ Monomers [g / mol]

HEMA: MAS 3959 3.92 15 crystalline 6.0 g / 96% 20:80

HEMA: MAS 5280 3.24 10 crystals 6.1 g / 97% 20:80 The residual monomer content was then determined by means of GC, as indicated in Table 7 below.

 Monomers are known to sensitize, so that as low as possible

 Monomer content is desired, which is advantageously achieved according to the invention.

The residual monomer analysis is carried out by GC under the conditions:

 Column Varian VCOT Fused silica, L. 50 m, 0 320 μΐη, detector FID,

Detector / injector temperature 250 ° C, temperature program start 60 ° C (3 min), heating 20 ° C / min to 100 ° C (5 min.), 10 ° C / min. up to 200 ° C (10 min.), 20 ° C / min. up to 240 ° C (2 min.), column pressure 50 KPa (constant), carrier gas H ₂ , N ₂ , device name Crompack CP-9003, evaluation software Chrompack CP Maestro 2.

Table 7: Residual monomer amounts determined by gas chromatography

The residual monomers can be determined both by GC and by HPLC. In order to reduce the residual monomer contents, initiator is additionally added after the polymerization in order to allow the residual monomers to react.

 After this step, no or only small amounts of residual monomer

 be detected (below the detection limit about 0.05% by weight)

TABLE 8 Residual monomer amounts determined by gas chromatography and HPLC

 amount of initiator

 amounts

Copolymer based on Σ the determined residual monomers

 [Wt.%] Monomers [mol%]

 20 HEMA <0.05

HEMA: MAS 20:80

 MAS <0.05

15 HEMA <0.05

HEMA: MAS 20:80

MAS 0.18 The copolymers according to the invention can additionally be crosslinked with small amounts of crosslinker. The proportion of crosslinker is preferably limited to 0.1 to 2 mol%, based on the monomers used.

 For example, the copolymers crosslinked with glycerol dimethacrylate (GDMA) and polyethylene glycol dimethacrylate (PEG-DMA (Mn: 550)) also show good properties such as good water solubility, moisture uptake and removal capacities as shown in Table 9 below:

In principle, crosslinking of copolymers is often not recommended. The crosslinking often leads to so-called clumping of the polymers and the desired

 Water solubility is thus put on play. As shown by the investigations in Table 9, however, crosslinking fractions of up to 2 mol% of the copolymers according to the invention can be reasonably expected without any loss of moisture-regulating properties. The moisture kinetics presented here and their advantages of

 Copolymers of the invention will be explained in more detail below.

Also, the GDMA and PEG-DMA crosslinked HEMA-MAS copolymers with a

 Crosslinker content of up to 2 mol.% Accordingly belong to the invention

 Copolymers.

The copolymers of the invention are surprisingly soluble in water and glycerol. Surprisingly, high dosages of the inventive copolymers in the water phase of water-based delivery systems such as emulsions, gels are thus possible.

Surprisingly, the copolymers according to the invention are neither gel-forming in water nor do they have a thickening effect.

The preparation of copolymers having small molecular weights in the range of less than 17,000 g / mol, in particular less than 10,000 g / mol and especially in the range of 3,000-7,000 g / mol, ensures that the negative properties of polymers mentioned in the prior art, such as gelation and thickening, not occur according to the invention.

The copolymers dissolve in water transparent, which their use in

cosmetic or dermatological preparations can also be interesting for optical reasons.

These solubility properties are important for use in cosmetic or dermatological preparation, because the copolymers according to the invention may be part of an emulsion as a later component and must therefore be able to mix rapidly with the other components of the water phase as part of the water phase.

In emulsions, the copolymers show the properties

a) to bind the residual water from the emulsion and thus to increase the skin moisture and / or b) to bind the glycerin from the emulsion and thus to increase the skin moisture

as shown by the above investigations.

As was also shown there, the copolymers according to the invention have an advantageous moisture uptake and release capacity.

Thus, the copolymers of the invention have been shown in studies to

Moisture absorption and release as well as unpredictable properties for solubility. For example, the copolymer HEMA: MAS (pH = 7) can absorb 59% or 60% of its own weight in water. This offers completely new applications for use as a component of cosmetics.

To determine which monomer combination of HEMA: MAS is a maximum

Moisture uptake capacity were achieved for this purpose HEMA: MAS copolymers produced in various ratios and determined their moisture absorption capacity after 8 hours and 48 hours.

 Advantageous moisture kinetics showed the copolymers with molar ratios HEMA to MAS in the range of 75:25 to 10:90. It was found that the copolymer of HEMA: MAS 20:80 (pH = 7) with 1 10.8% of its own weight can absorb the maximum amount of water, which represents amazing capacity.

Table 10 shows the solubility of the copolymers in water and glycerol:

 - = poorly soluble, + = mostly soluble, ++ = completely soluble

To measure the moisture absorption capacity of the copolymers, a defined amount of the copolymers prepared in each case was weighed into a weighing dish by dissolving the respective amount in 5 ml of water and then quantitatively transferring it to the weighing dish. The weighing dish filled in this way with the polymer solution was placed in a drying oven heated to 40 ° C. for exactly 12 ± 1 hour, so that a uniform polymer film was formed. After reaching the weight constancy, the small bowl and its contents are transferred to a special device for determining the moisture absorption capacity.

Table 1 Figure 1 shows an overview of the measured HEMA: MAS copolymers

The moisture absorption device was in the form of a cocktail shaker

(Dimensions LxWxH: 90x90x220 mm) and consists of a reservoir for aqueous solutions over which a plastic sieve is attached. On this sieve, which is about 10 cm above the liquid, the weighing dish is placed and closed the shaker with a lid.

 The liquid used is a saturated aqueous solution of potassium chloride, which produces an air humidity of 84.3% at 25 ° C. The humidity set in this way corresponds to the humidity averaged over the year in Germany.

 By differential weighing the weight of the weighing pan with its content in certain

 Time intervals it is possible to track the water absorption of the polymer film.

 Moisture uptake measurements were performed according to the measurement parameters given in Table 12:

 Table 12: Parameters of the moisture absorption measurements

Figures 2 to 6 show the moisture absorbency of the copolymers. There are both dependencies on the pH, the monomer ratio and the

 Initiator amount has been investigated.

 It turns out that while the pH, monomer ratio and amount of initiator exert an influence on the water absorption capacity of the copolymers, the capacities are all in the range according to the invention.

The HEMA-MAS copolymer (20:80) according to the invention can, for example, take up 72% or 100% of the intrinsic weight of water in 8 hours, as shown in FIG. 6. The moisture release measurement was made following the 8-48 hour moistening of the polymer films by means of a saturated potassium carbonate sesquihydrate solution. For this purpose, the saturated potassium chloride solution was removed from the shaker and this filled after thorough cleaning and drying with the saturated potassium carbonate solution. The

 The weighing dish together with the polymer film was now placed in the shaker and exposed in this way to an interior atmosphere with a relative humidity of 43.2%. The

 Measurements were made over 8 hours with hourly recording.

The moisture delivery measurement was carried out according to the measurement parameters given in Table 13 below:

Table 13: Parameters of the moisture delivery measurements

Figures 7 to 10 show the thus determined moisture release values of the HEMA-MAS copolymers as a function of HEMA-MAS ratio and amount of initiator.

 The particularly preferred copolymer HEMA-MAS 20:80 according to the invention still retains 30% of its own weight in residual moisture after 8 hours, as Figure 10 shows.

The use of HEMA-MAS copolymers as a long-term humectant is thus possible. Tables 14 to 16 below show a comparison of moisture kinetics. Table 14:

Table 15:

 Copolymer Initiator Solubility Solubility WaterWaterWater amount medium of 150mg uptake in charge in 8h [mol%] polymer in 8h at 84% 48h at 84% at 43% rel.

 2.5mL rel. rel. humidity

Solvent Humid air-humidity and film thickness at RT [+/-] speed and 0.1 mm [%]

 Film thickness Film thickness

 0.1 mm [%] 0.1 mm [%]

 HEMA: MAS 20 Dem. ++ 53.9 69.5 14.7

 75:25 pH = 7 water

 10% ++

 Glycerol solution

 HEMA: MAS 20 Dem. ++ 60.0 72.8 15.5

 50:50 pH = 7 water

 10% ++

 Glycerol solution

 HEMA: MAS 20 Dem. ++ 67.8 87.8 23.5

 40:60 pH = 7 water

 10% ++

 Glycerol solution

HEMA: MAS 20 Dem. ++ 74.9 95.8 25 30:70 pH = 7 water

HEMA: MAS 20 Dem. ++ 80.9 1 10.8 31.2

 20:80 pH = 7 water

 10% ++

 Glycerol solution

 HEMA: MAS 20 Dem. ++ 30.5 39.1 8.0

 10:90 pH = 7 water

 10% ++

 Glycerol solution

 - = poorly soluble, + = mostly soluble, ++ = fully soluble

Table 16:

It was found that the moisture absorption capacity was significantly different from the

 Monomerverhältnissen depends on each other. Thus, starting from the HEMA: MAS 25:75 copolymer up to the HEMA: MAS 20:80 copolymer was a steadily increasing

 Moisture absorption capacity. The maximum is not as expected when

HEMA: MAS 10: 90 copolymer but at the HEMA: MAS 20:80 ratio. One with 69.5 The HEMA: MAS 25: 75 copolymer already has a similarly high capacity. The HEMA: MAS copolymers from the monomer ratios 50:50 (72.8%), 40:60 (87.8%), 30:70 (95.8%) and 20:80 (1 10.8%) have an increasing capacity.

The moisture release measurement carried out after reaching saturation gave an analogous result. Thereafter, the HEMA: MAS 20:80 copolymer with 79.6% gives off most of the HEMA: MAS 10: 90 copolymer with 31.1 the least in 8 hours.

The HEMA-MAS copolymers, especially those having an average molecular weight of less than 10,000 g / mol and a HEMA-MAS ratio in the range of 75:25 to 10:90, are moisture regulators because of their water and glycerol solubility as well as the moisture uptake and release properties in different areas and

Formulations usable. In particular, the copolymers according to the invention can be used as moisture regulators in cosmetic or dermatological preparations in that they can advantageously help to improve skin moisturization.

The further comparative investigations also confirm the water absorption capacity of the copolymers according to the invention.

 Thus, water absorption tests at 32 ° C were carried out by various cosmetics known in cosmetics, such as moisturizers and emulsifiers, after 6 hours, 1 day and 1 week. 32 ° C represents the usual skin surface temperature.

Table 17 below shows the water absorption at 32 ° C and 100% rel. Humidity. The increase was determined gravimetrically in relation to the starting weight.

Table 17: Water uptake capacities

 It turns out that the copolymers according to the invention are approximately good

Water absorption such as glycerol known as humectants, sorbitol and urea.

In a further comparative study, the water content in pig skin was determined, which represents a more application-oriented method of determining the moistening performance of cosmetic substances.

The determination was carried out by means of ATR-IR spectroscopy. Figure 1 1 shows the comparison of the water content in pig skin. For comparison, the water content in pigskin was measured with glycerol and against untreated. The water absorption and moistening performance of the copolymers according to the invention in the skin is thus shown. Surprisingly, the wetting performance of the copolymers is even in the range of glycerol.

As a further proof of the skin moisturizing performance of the HEMA-MAS copolymers according to the invention, a long-term corneometry study has been carried out. For this purpose, two 5% aqueous solutions of the HEMA-MAS copolymers (copolymer with Mn = 3387 g / mol and copolymer with Mn = 6277 g / mol) 2 times a day for 2 weeks applied to the forearms of subjects. Before the first product application (tO), 7 days (t1) and 14 days after the first product application (t2), skin moisturization of the respective treated areas as well as an untreated area of the forearm was measured by corneometry. Coreanometer unit differences t1 -t0 and t2-t0 are shown in Figure 12.

 Figure 12 shows that the copolymer solutions have higher levels of skin moisturization than the untreated areas. The HEMA-MAS copolymer solutions moisturize the skin and are beneficial as skin moisturizers in cosmetic or cosmetic applications

dermatological preparations thus usable.

The HEMA-MAS copolymers are thus excellently suitable as a skin moisturizer with the advantages of a skin moisturizing on the surface and a film formation on the surface

Surface that prevents the rapid evaporation of water on the skin surface and protects the skin from environmental influences.

In addition, the olfactory properties of the copolymers according to the invention have also been investigated, as shown in Table 18 below.

Table 18 Olfactory properties

 Operating ratio Optical odor test

HEMA: MAS appearance

75: 25 White Powder Minimal

 odor

 50: 50 White Powder Minimal

 odor

40: 60 white powder min odor

 30: 70 White Powder Minimal

 odor

 20: 80 White Powder Minimal

 odor

 10: 90 white powder min

 odor

As Table 18 shows, the copolymers according to the invention can be used as a cosmetic component therefore also for aesthetic / olfactory reasons. This is often not the case with the conventional polymers of the prior art.

Due to their very good solubility in water, the copolymers according to the invention make it possible that their proportion in water-based delivery systems, such as, for example, gels or emulsions, is far beyond the usual proportions of the polymers of the prior art.

 Advantageously, the copolymers according to the invention can be added to a proportion of up to 50% by weight of the preparation. In particular, the proportion by weight of

Copolymers of the invention advantageously in the range of 1 to 20 wt.%, In particular in the range of 2.5 to 10 wt.%, Based on the total mass of the preparation.

The copolymers according to the invention have relatively small molecular weights of less than 17,000 g / mol, advantageously less than 10,000 g / mol and in particular in the range of 3,000 to 7,000 g / mol, and are nevertheless extremely good at absorbing water. Especially from dry phases, such as as emulsion residue on the skin or

water-binding after release of water at 40% relative humidity (dry rooms).

As the investigations have shown, for example, the copolymer still retains 30% residual moisture (at 43% relative humidity) 8 hours after application, which can further moisturize the skin. A long-term humidifying effect is thus given.

The HEMA-MAS copolymers are water-soluble. Water-soluble is to be understood as

Solubility of at least 10 g of copolymer per 100 g of water at a temperature of 20 ° C. Despite the low tackiness of the copolymers when the water-soluble polymer is applied to the skin and the water evaporates slowly, leaving only the

Polymer residue remains on the skin, a film can form on the skin surface.

The copolymers according to the invention in water do not form gels makes them universally applicable without having to consider additional viscosity problems of the final preparations. In the same way is advantageous to see their property in aqueous

Preparations or emulsions not thickening effect.

The non-gelation as well as the non-thickening effect of the invention

Copolymers makes a decisive difference to the polymers known from the prior art with (meth) acrylate.

 The non-gelation and non-thickening action of the copolymers according to the invention was determined by means of viscosity measurements of the example preparations 11, 13, 16 and 18

examined. The viscosity was determined using a Viscotester VT-02 from Haake at 20 ° C. with the aid of the rotating body 1 or 2 and reading the scale 1 or 2 (corresponds to a shear rate of 10 Pa / s).

The following viscosities were evident:

 Example 1 1: O / W emulsion with glycerol and without HEMA-MAS copolymer: 5750 mPas Example 13: O / W emulsion with glycerol and 5% by weight HEMA-MAS copolymer: 4200 mPas Example 16: O / W emulsion without glycerine and without HEMA-MAS copolymer: 5800 mPas Example 18: O / W emulsion without glycerol and with 5 wt.% HEMA-MAS copolymer: 3950 mPas.

The viscosity data show that the addition of HEMA-MAS copolymer does not increase the viscosity of the preparations. The HEMA-MAS copolymers therefore have no gel-forming or thickening effect in aqueous formulations.

Likewise, a gelation or thickening is also not visible optically.

On the contrary, the viscosity measurements show that the viscosity of the preparations with HEMA-MAS copolymers is surprisingly lower than the comparable ones

Preparations without HEMA-MAS copolymers. The HEMA-MAS copolymer may even make the system slightly more fluid, lower viscous.

The use and the use of the copolymers according to the invention is possible in various dosage forms, ie preparations or agents. The HEMA-MAS copolymers according to the invention can be used in particular in water-based preparations in which a water solubility, water absorption or disposal is advantageous and a Influence on the viscosity of the preparations should be avoided (avoiding gelation or thickening).

The HEMA-MAS copolymers can in particular in any usual

Forms of preparation are used, such as W / O emulsions, O / W emulsions,

Hydrodispersions, gels, alcoholic preparations, cosmetic sprays, pads, cloth, plaster, W / S, b / w, microemulsion, nanoemulsion, mousse, foam, PIT emulsion, hydrogel, hydrodispersion gel, multiple emulsion, ointment, cream gel, cream Lotion, in particular W / O, O / W or W / O / W emulsions. The HEMA-MAS copolymers according to the invention can also be used in gel preparations, the gel then naturally not being formed on the basis of the HEMA-MAS copolymers but on the basis of the customary gel preparation ingredients.

Preference is given to cosmetic or dermatological preparations to which the copolymers according to the invention can be added. The preparations according to the invention may then further contain cosmetic adjuvants and other active ingredients such as are commonly used in such preparations, e.g. Preservatives, preservatives, bactericides, perfumes, foaming inhibitors, colorants and pigments, thickeners, wetting and / or

moisturizing substances, fats, oils, waxes or other common ingredients of a cosmetic or dermatological formulation such as alcohols, polyols, polymers, foam stabilizers, electrolytes, organic solvents or silicone derivatives, provided that the additive does not affect the required properties.

Advantageously, the cosmetic or dermatological preparations comprise active ingredients and / or derivatives thereof, such as. Alpha-lipoic acid, phytoene, D-biotin, coenzyme Q10, alpha-glucosylrutin, carnitine, carnosine, natural and / or synthetic isoflavonoids, creatine, fumaric acid esters, ectoine and its derivatives, tea extracts, folic acid, arginine and its salts, taurine, Glyceryl glucose and / or β-alanine. These active ingredients may be contained in a proportion of 0.001 to 10% by weight, based on the total weight of the preparation, advantageously in this.

In addition to its own moistening performance, which is mediated by the use of HEMA-MAS copolymers the preparations, more humectants, so-called moisturizers can be added to the preparations. Moisturizers are substances or mixtures of substances which give cosmetic or dermatological preparations the property of reducing the moisture release of the horny layer (also called transepidermal water loss (TEWL) after application or spreading on the skin surface) and / or hydrating the horny layer positively to influence.

 The proportion of additional skin moisturizing agents is preferably in the range from 1 to 20% by weight, based on the total mass of the preparation.

Advantageous moisturizers for the purposes of the present invention are in particular glycerol. However, furthermore, lactic acid, butylene glycol, sorbitol, pyrrolidonecarboxylic acid, polymeric moisturizers from the group of water-soluble and / or water-swellable and / or water-gellable polysaccharides can be used as moisturizers. Particularly advantageous are, for example, short-chain hyaluronic acid (<50,000 daltons) and long-chain hyaluronic acid (> 50,000 daltons), chitosan and / or a fucose-rich polysaccharide, which is filed in the Chemical Abstracts under the registry number 178463-23-5 and z. B. under the name Fucogel®1000 from the company SOLABIA S.A. is available.

In particular in combination with the known moisturizers, such as glycerol, a double wetting effect can be achieved with the copolymers according to the invention.

Glycerin acts in cosmetic or dermatological preparations

known as a deep moisturizer and the HEMA-MAS copolymers as

Oberflächenbefeuchter.

Due to their properties, the HEMA-MAS copolymers according to the invention increase the care and / or active power of cosmetic or dermatological preparations. It means according to the invention an increase in nursing or

Active performance that the care or active power, such as the moistening of the skin caused by the one or more copolymers compared to a

Preparation containing the same ingredients without the copolymers is increased.

The preparations according to the invention can be formulated for topical application. According to the invention, topically administrable preparations are in particular

Lotions, gels, emulsions, aerosol mousse, pumpable preparations, creams and with the preparations soaked or loaded towels, pads or patches understood. The following examples show cosmetic preparations in which the copolymers according to the invention have been incorporated. The numbers refer to parts by weight based on the total mass of the respective preparation.

 Examples 1, 6, 11 and 16 are comparative examples which are not according to the invention and which have a reduced moisture performance compared with the example preparations according to the invention.

Examples

Ingredients 6 7 8 9 10

Cyclomethicones 5 5 5 5 5

 Butyrospermum Parkii Butter 1 1 1 1 1

 Butylene Glycol 2 2 2 2 2

 Aqua + Sodium Hydroxide 0.52 0.52 0.52 0.52 0.52

Methylparaben 0.15 0.15 0, 15 0, 15 0, 15

Phenoxyethanol 0.4 0.4 0.4 0.4 0.4

Acrylates / C 10-30 Alkyl Acrylate Crosspolymer 0.8 0.8 0.8 0.8 0.8

Ammonium Acryloyldimethyltaurate / VP Copolymer 0.2 0.2 0.2 0.2 0.2

Aqua 86.63 84, 13 81, 63 79, 13 76.63

Alcohol Denat. 3 3 3 3 3

 Perfume 0.3 0.3 0.3 0.3 0.3

Polymer HEMA-MAS (20:80) Mn = 3387 g / mol 0 2.5 5 7.5 10 O / W emulsions

Ingredients 16 17 18 19 20

Tocopheryl acetate 0.5 0.5 0.5 0.5 0.5

Ethylhexylglycerol 0.5 0.5 0.5 0.5 0.5

Caprylic / Capric Triglycerides 1 1 1 1 1 Cera Microcristallina + Paraffin Liquidum 3 3 3 3 3

 Cetearyl Alcohol 4 4 4 4 4

 Dimethicone 0.5 0.5 0.5 0.5 0.5

 C12-15 alkyl benzoate 2 2 2 2 2

 Butyrospermum Parkii Butter 3 3 3 3 3

 Glyceryl Stearate 2.6 2.6 2.6 2.6 2.6

 PEG-40 Stearate 0.8 0.8 0.8 0.8 0.8

 Aqua + Sodium Hydroxide 0.6 0.6 0.6 0.6 0.6

 Ethylparaben 0, 1 0, 1 0, 1 0, 1 0, 1

 Methylparaben 0.2 0.2 0.2 0.2 0.2

 Propylparaben 0, 1 0, 1 0, 1 0, 1 0, 1

 Phenoxyethanol 0.4 0.4 0.4 0.4 0.4

 Methylpropanediol 4 4 4 4 4

 Carbomer 0, 1 0, 1 0, 1 0, 1 0, 1

 Chondrus Crispus 0,2 0,2 0,2 0,2 0,2

 Aqua 64, 15 61, 65 59, 15 56.65 54, 15

Aqua + Trisodium EDTA 1 1 1 1 1

 Ethylhexyl methoxycinnamate + BHT 7 7 7 7 7

 Butyl methoxydibenzoylmethane 2 2 2 2 2

 Phenylbenzimidazole sulfonic acid 1, 5 1, 5 1, 5 1, 5 1, 5

 Titanium Dioxide + Trimethoxycaprylyisilane 0,5 0,5 0,5 0,5 0,5

 Perfume 0.25 0.25 0.25 0.25 0.25

 Polymer HEMA-MAS (20:80) Mn = 3387 g / mol 0 2.5 5 7.5 10

Ingredients 21 22 23 24 25

Tocopheryl acetate 0.5 0.5 0.5 0.5 0.5

Ethylhexylglycerol 0.5 0.5 0.5 0.5 0.5

Caprylic / Capric Triglycerides 1 1 1 1 1

Cera Microcristallina + Paraffin Liquidum 3 3 3 3 3

Cetearyl Alcohol 4 4 4 4 4

Dimethicone 0.5 0.5 0.5 0.5 0.5

C12-15 alkyl benzoate 2 2 2 2 2

Butyrospermum Parkii Butter 3 3 3 3 3

Glyceryl Stearate 2.6 2.6 2.6 2.6 2.6

PEG-40 Stearate 0.8 0.8 0.8 0.8 0.8 Glycerine 8,693 8,693 8,693 8,693 8,693

Aqua + Sodium Hydroxide 0.6 0.6 0.6 0.6 0.6

Ethyl paraben 0.1 0.1 0.1 0.1 0.1

Methylparaben 0.2 0.2 0.2 0.2 0.2

Propylparaben 0.1 0.1 0.1 0.1 0.1

Phenoxyethanol 0.4 0.4 0.4 0.4 0.4

Methylpropanediol 4 4 4 4 4

Carbomer 0.1 0.1 0.1 0.1 0.1

Chondrus Crispus 0,2 0,2 0,2 0,2 0,2

Aqua 50,457 52,957 50,457 47,957 45,457

Aqua + Trisodium EDTA 1 1 1 1 1

Ethylhexyl methoxycinnamate + BHT 7 7 7 7 7

Butyl methoxydibenzoylmethane 2 2 2 2 2

Phenylbenzimidazole sulfonic acid 1.5 1.5 1.5 1.5 1.5

Titanium Dioxide + Trimethoxycaprylylsilane 0.5 0.5 0.5 0.5 0.5

Perfume 0.25 0.25 0.25 0.25 0.25

Polymer HEMA-MAS (20:80) Mn = 3387 g / mol 0 1.5 1.0 0 1

Polymer HEMA-MAS (20:80) Mn = 5280 g / mol 5 1 2.5 0 5

Polymer HEMA-MAS (20:80) Mn = 9570 g / mol 0 0 1.5 7.5 4

Claims

claims 1 . 2-hydroxyethyl methacrylate - methacrylic acid copolymers of the structure

characterized in that R1 and R2 represent initiator radicals and Z ⁺ cationic radicals and the coefficients m in the range m = 2 to 58 and n = 8 to 105 are selected and the average molecular weight of the copolymers is less than 17,000 g / mol. 2. Copolymers according to claim 1, characterized in that the initiator radicals R 1, R _{2 are} selected from the group -H, -SO ₄ , -OH, the cationic radicals Z ^{+ are} selected from H, Na, K, Ca, NH ₄ or Alkylammonium compounds NR ₃ R ₄ R ₅ R ₆ with R ₃ -R ₆ HH, CH ₃ or C ₂ H _5,  - m (H EMA) in the range 2 to 45,  - n (MAS) in the range 8 to 75 and / or M ^"j _m range <10,000 g / mol, in particular in the area of 3,000 to 7,000 g / mol are chosen 3. Copolymers according to claim 1 or 2, characterized in that the molar ratio of 2-hydroxyethyl methacrylate to methacrylic acid in the range 10: 90 to 75 to 25 is selected. 4. Water-based administration forms comprising one or more copolymers according to one of claims 1 to 3. 5. Dosage form according to claim 4 as a cosmetic or dermatological preparation. 6. dosage form according to claim 4 or 5, characterized in that the  Weight fraction of the copolymers up to 50 wt.%, In particular in the range of 1 to 20 wt.%, In particular in the range of 2.5 to 10 wt.%, Based on the total mass of the dosage form is selected. 7. Preparations according to claim 5 or 6 comprising one or more additional  Skin moisturizer, especially glycerin. 8. Use of the copolymers according to one of claims 1 to 3 as  Feuchtigskeitsregulatoren. 9. Use of the copolymers according to claim 8 in cosmetic or dermatological preparations for moisturizing the skin. 10. Use according to claim 9, characterized in that one or more  additional skin moisturizers, in particular glycerol, to which preparations have been added.