FR2889194A1 - BLOCK COPOLYMER COMPRISING LCST BLOCK HAVING LOW SOLUBILITE CRITICAL TEMPERATURE, FORMULATIONS COMPRISING THE COPOLYMER, AND USE FOR VECTORIZING AN ACTIVE INGREDIENT - Google Patents

Abstract

The present invention discloses a novel copolymer comprising a block having a critical lower solubility temperature (LCST). The present invention also describes formulations comprising the copolymer, and the use of the copolymer or formulations for targeting an active ingredient. The copolymer and the formulations may especially be used in the field of cosmetics, pharmacy, in the fields of household care or in the fields of surface coatings.

Description

Block copolymer comprising an LCST block having a temperature

  The present invention relates to a novel copolymer comprising a block having a critical minimum temperature of solubility (LCST). The present invention also provides formulations comprising the copolymer, and the use of the copolymer or formulations for targeting an active ingredient.

  The copolymer and the formulations of the invention may in particular be used in the field of cosmetics, pharmacy, in the fields of household care or in the fields of surface coatings.

  In many fields, particularly in the fields of cosmetics, pharmacy, and household care, formulations are made comprising active ingredients, intended to bring a property to a medium or a surface. Formulations thus comprise a liquid vector, a vectorized product, and ingredients for formulation aid, for example protection, encapsulation, vectorization, stabilization, dispersion, rheology, and / or control of these functions. , if necessary under the influence of a parameter external to the formulation. These ingredients can of course also be active.

  As a formulation ingredient, and possibly also an active ingredient, it is known to use copolymers having a critical lower solubility temperature, referred to as LCST.

  According to the present invention, copolymers having an LCST are referred to as LCST copolymers.

  WO 02/055607 discloses (grafted) comb copolymers having a hydrophilic backbone, for example deriving from polyacrylic acid, and LCST grafts of poly-N-isopropylacrylamide (pNIPAM) or LCST grafts comprising a polyether group. The document also suggests block copolymers, used to improve the stability of formulations, especially cosmetic creams, when subjected to different temperatures, by formation of a gel upon an increase in temperature.

  WO 95/24430 discloses graft copolymers comprising a hydrophilic backbone and LCST grafts, for example a copolymer having a backbone derived from acrylic acid, and grafts derived from N-isopropylacrylamide (NIPAM), obtained by the coupling reaction. between two polymers, one of which is poly (acrylic acid) and the other is for example the PNIPam terminated by NH2. The copolymer makes it possible to control the release of a dispersed active agent in a composition comprising the copolymer.

  There is a need for new copolymers which can in particular confer new properties or functions on new formulations.

  The Applicant has found that these needs can be filled by a controlled architecture copolymer, preferably a linear block copolymer, comprising at least two different blocks A and B, at least one of which, block A for example, is a block having a critical lower temperature. of solubility (LCST) comprising LCST units.

  Thus, the present invention provides a controlled architecture copolymer, preferably a linear block copolymer, comprising at least two different blocks A and B, chosen such that: block A is a block having a critical lower solubility temperature (LCST) comprising LCST units, - block B is a block comprising organosiloxane units.

  According to the invention, LCST unit means either a unit resulting from the polymerization of a monomer whose corresponding homopolymer has an LCST, or a unit resulting from the polymerization of a macromer having an LCST.

  The present invention also provides a formulation comprising: - an aqueous liquid carrier, - optionally a vectorized product, being a non-water soluble active ingredient or a non-water soluble composition comprising a water-soluble or non-water-soluble active ingredient, and - the architecture-controlled copolymer according to the present invention. 'invention.

  In the present application, linear block copolymer is a copolymer having at least two blocks of different compositions, interconnected, and forming a linear macromolecular chain. It is not excluded that the blocks have macromolecular side groups. These groups when they exist will not be considered blocks of the block copolymer.

  In the present application, the unit derived from a monomer denotes a unit that can be obtained directly from said monomer by polymerization. Thus, for example, a unit derived from an ester of acrylic or methacrylic or vinylic acid does not cover a unit of formula CH2-CH (COOH) -, -CH2-C (CH3) (O00H) -, CH2-CH (OH) -, respectively, obtained for example by polymerizing an acrylic or methacrylic acid ester, or vinyl acetate, respectively, and then hydrolyzing. A unit derived from acrylic or methacrylic acid for example covers a unit obtained by polymerizing a monomer (for example an acrylic or methacrylic acid ester), then reacting (for example by hydrolysis) the polymer obtained so as to obtain units of formula CH2-CH (COOH) -, or CH2-C (CH3) (000H) -. A unit derived from a vinyl alcohol for example covers a unit obtained by polymerizing a monomer (for example a vinyl ester), then reacting (for example by hydrolysis) the polymer obtained so as to obtain units of the formula -CH2- CH (OH) -.

  Typically, the theoretical average molar mass Mb, oc of a block, is calculated according to the following formula: Mbloc = [M] o * [Precursor] o * Conversion * (M) monomer.

  Where [M] o is the initial monomer concentration [Precursor] o is the initial precursor concentration (reversible transfer agent, initiator or first block) Conversion means conversion to monomer (M) monomer refers to the molar mass of the monomer .

  The measured average molar mass of a copolymer, unless otherwise indicated, is a number-average molar mass, measured by steric exclusion chromatography (SEC), after formation of the copolymer.

  The average measured molecular weight of a block, unless otherwise indicated, is a number-average molar mass, measured by steric exclusion chromatography (SEC), after formation of the block, to which the measured molar mass of a previously formed block.

  In the present application, the term hydrophobic is used in its usual sense of which has no affinity for water; this means that the organic polymer of which it is made, taken alone (with the same composition and the same molar mass), would form a two-phase macroscopic solution in distilled water at 25 ° C. at a concentration greater than 1% by weight.

  In the present application, the term hydrophilic is also used in its usual sense of which has affinity for water, that is to say is not likely to form a two-phase macroscopic solution in water distilled at 25 ° C. at a concentration greater than 1% by weight.

  The first subject of the invention is thus preferably a linear block-controlled copolymer comprising at least two different blocks A and B, characterized in that: block A is a block having a lower critical solubility temperature ( LCST) comprising LCST units, - block B is a block comprising organosiloxane units.

  The copolymer according to the invention may be a diblock copolymer (block A) (block B), a triblock copolymer (block A) - (block B) - (block A) or a graft copolymer (block A) -g- (block B) or alternatively (Block B) -g- (Block A), each block consisting of monomer units belonging to the same monomer or to different monomers.

  The copolymer of the invention is water-soluble or water-dispersible.

  Block A soluble or dispersible in water has an LCST of between 5 and 80 C. This LCST depends on the composition of the block A and the nature of the units composing it. Beyond this LCST, block A becomes insoluble in water.

  Block A comprises LCST units, that is to say units derived from an LCST monomer, mixtures of LCST monomers or one or more LCST monomers mixed with monomers whose homopolymers do not exhibit of LCST.

  The LCST monomers are chosen from the group comprising the following monomers: vinylcaprolactam, N-ethyl acrylamide, N, N'-methylethyl acrylamide, N, N'-diethyl acrylamide, N-isopropyl acrylamide, N-isopropyl methacrylamide, 2-carboxy isopropyl acrylamide, N-methylisopropyl acrylamide, N-propyl acrylamide, N-acryloyl N'-methylpiperazine, Nacryloyl N'-ethylpiperazine, N-acryloyl N'-propylpiperazine, N-propyl methacrylamide, N- (L) - (1-hydroxymethyl) propyl methacrylamide, N, N'methylpropyl acrylamide and the monomers corresponding to the following formulas: The units with an LCST are chosen from the following units: units comprising at least one polyether group, such as poly (ethylene oxide and / or oxide) propylene) in the form of macromolecular chains with a single type of units, or with several types of units, statistical or sequential, units comprising a polyvinyl methyl ether group (macromonomer), units with a LCST derived from my substituted acrylamide or methacrylamide, - vinyl caprolactam, - macromonomers comprising units derived from substituted acrylamide or methacrylamide monomers (macromonomer).

  The units with an LCST are preferably those derived from substituted acrylamide or methacrylamide monomers such as: N-isopropyl acrylamide, N-ethyl acrylamide, vinyl caprolactam, and mixtures thereof.

  In general, non-LCST monomers are hydrophilic monomers with ethylenic unsaturations such as acrylamide, or hydrophobic ethylenically unsaturated such as N-butyl acrylamide.

  The copolymer of the invention is defined so as to have an LCST adapted to the intended application.

  Block A represents at least 30% by weight of the copolymer and preferably between 50 and 95% by weight of the copolymer. It has a number average mass of between 500 and 100000 and preferably between 2000 and 20000.

  According to the invention, block B comprises: organosiloxane units of formula -SiR12O- in which R1 is a hydrocarbon group, preferably a methyl group, optionally organosiloxane units of formula SiR22O- or SiR1 R2O- in which R1, R2 In the context of the invention, alkyl is understood to mean an alkyl, a linear or branched hydrocarbon-based chain containing from 1 to 10 carbon atoms and preferably from 1 to 4 atoms. of carbon.

  Examples of preferred alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl and t-butyl.

  Cycloalkyl means a monocyclic cyclic hydrocarbon group comprising 5 or 6 carbon atoms, preferably a cyclopentyl or cyclohexyl group.

  By aryl is meant an aromatic mono- or polycyclic group, preferably mono- or bicyclic comprising from 6 to 12 carbon atoms, preferably phenyl.

  The siloxane compounds which are used in the process of the invention correspond to the formula (I) in which R 1 and R 2 are identical and more particularly represent an alkyl group having from 1 to 4 carbon atoms.

  R 'and R2 preferably represent a methyl group.

  The average number-average mass of block B is between 500 and 100,000 and preferably between 1000 and 10,000.

  One of the other subjects of the invention is a formulation comprising: an aqueous liquid vector, optionally a vectorized product, being a non-water-soluble active ingredient or a non-water-soluble composition comprising a water-soluble or non-water-soluble active ingredient, and at least one copolymer according to the invention.

  The vectorized product is dispersed in the liquid vector, in the form of a dispersion of solid particles stabilized by the copolymer, or dispersion in the core of micelles of the copolymer, the formulation being at a temperature below the critical lower temperature of the solubility of the block. A. The formulations of the invention find their applications in various fields.

  We can quote as indicative titles. and non-limiting formulations intended to be applied to the skin and / or the hair, on textile fibers, or hydraulically bound formulations, for example cementitious formulations (the copolymer is a water repellent). There may also be mentioned some applications in the field of coatings such as paints, varnishes, adhesives, etc.

  The formulations of the invention are useful for vectorizing an active ingredient on a surface, by applying the formulation on said surface, and increasing the temperature, it is increased by any suitable means known to those skilled in the art such as for example rinsing after application with water at a temperature higher than that of the formulation before application.

  Other details or advantages of the invention may appear in view of (s) example (s) below only for information. Examples: Example 1. Synthesis of a triblock copolymer Poly (N-isopropylacrylamide) b-Poly (dimethylsiloxane) -b-Poly (N-isopropylacrylamide) The two steps 1 and 2 to access the functionalized silicone xanthate oil C 35 are described in Figure 1 below. hosi

If Sil \ OH -13 I

A Br

  O O Br O \ / O / \ Sig 'si- O II Br - I-13 1

S

I I

I o I -o 1 Br KS \ O

O O

  O Si Si Si O s s 1 1 s s Figure 1. Process for functionalization of a silicone oil with O-ethyl xanthate groups.

  Step 1: Synthesis of functionalized poly (dimethylsiloxane) B bromopropionate at positions a and co: 0.88 ml (2.4 equivalents) of 2-bromopropionyl bromide are added dropwise at room temperature to a solution containing 10 g of dichloromethane. a poly (dimethylsiloxane) A oil of Mn 2700 g / mol (1 equivalent) and 1.2 g (4 equivalents) of pyridine in 200 ml of ethyl ether. After one night at room temperature, 50 ml of water are introduced. Two extractions per 100 ml of ethyl acetate are then carried out. The organic phases are mixed and then washed successively with a 1M aqueous NaOH solution, a 10% aqueous solution of HCl, brine and then dried with MgSO 4. The solvents are then evaporated and the crude reaction product is purified by column chromatography on silica gel (heptane 9 / ether 1) to give 11 g of the functional silicone oil B.

B

O

  1H NMR (CDCl3) b 0 (m, Si-CH3), 0.55 (m, 4H), 1.7 (m, 4H), 1.83 (d, 6H), 4. 12 (m, 4H), 4.37 (q, 2H); ).

  Step 2: Synthesis of Functionalized 0-ethyl 5 xanthate Functionalized Poly (dimethylsiloxane) C at the α and Co: Positions of Functionalized Silicone Bromopropionate B Oil is added to a solution of 1.07 g of potassium ethyl xanthate (4 equivalents) in 150 ml of acetonitrile. The reaction is maintained for 4 hours at room temperature. The solvent is then evaporated and the polymer is dissolved in ethyl ether; the mixture is then filtered. After evaporation of the solvent, 5.2 g of silicone C are recovered.

  The 1 H NMR of the final product shows the characteristic signals of the 0-ethyl xanthate chain end, with chemical shifts at 4.40 and 4.60 ppm respectively corresponding to methine (RO (C = O) CH (Me) S (C) = S) OCH2-CH3) and the two methylenic hydrogens (RO (C = O) CH (Me) S (C = S) OCH2-CH3).

  Step 3: Polymerization of N-isopropyl acrylamide (NIPAm) in the presence of poly (dimethyl siloxane) C functionalized O-ethyl xanthate at positions aetw: In a two-necked 50 ml flask equipped with magnetic stirring and a condenser, 5.19 g of N-isopropyl acrylamide (NIPAm), 1 g of silicone oil C and 6.19 g of dioxane are introduced. The mixture is heated to 70 ° C., at which temperature 0.056 mg of azobisisobutyronitrile are introduced. The reaction is stopped after 9 hours. 1H NMR analysis confirmed that the NIPAm monomer is completely consumed. DOSY NMR analysis has made it possible to demonstrate that the precursor PDMS population C is fully activated by transfer of the xanthate group during the polymerization of P (NIPAm). The triblock copolymer P (NIPAm) -bPDMS-b-P (NIPAm) is thus obtained.

Claims (15)

  A co-controlled architecture copolymer, preferably a linear block copolymer, comprising at least two different blocks A and B, characterized in that: block A is a block having a critical lower solubility temperature (LCST) comprising LCST units; block B is a block comprising organosiloxane units.   2. Copolymer according to claim 1 characterized in that the LCST of the block A is between 5 and 80 C. 3. Copolymer according to one of the preceding claims characterized in that it is water-soluble or water-dispersible.   4. Copolymer according to one of the preceding claims, characterized in that the copolymer is - a diblock copolymer (block A) - (block B), - a triblock copolymer (block A) - (block B) - (block A ), a graft copolymer (blockA) -g- (block B) or (block B) -g- (block A).   5. Copolymer according to one of the preceding claims, characterized in that the block A comprises LCST units and units derived from hydrophilic non-LCST monomers with ethylenic unsaturations such as acrylamide or hydrophobic ethylenically unsaturated such as N-butyl acrylamide .   6. Copolymer according to claim 5 characterized in that the LCST units are chosen from the following units: - units comprising at least one polyether group, such as poly (ethylene oxide and / or propylene oxide) in the form of macromolecular chains of a single type of units, or of more than one type of unit, statistical or sequential, - units comprising a polyvinylmethylether (rnacromonomer) group, - units with an LCST derived from substituted acrylamide or methacrylamide monomers, - vinyl caprolactam - macromonomers comprising units derived from substituted acrylamide or methacrylamide monomers (macromonomer).   7. Copolymer according to claim 6, characterized in that the units with LCST derived from substituted acrylamide or methacrylamide monomers, are chosen from: - N-isopropyl acrylamide, - N-ethyl acrylamide, - vinyl caprolactam - their mixtures.   8. Copolymer according to one of the preceding claims, characterized in that the block B comprises: - organosiloxane units of formula SiR'2O- in which R ', identical or different is a hydrocarbon group, preferably a methyl group, - optionally organosiloxane units of formula SiR22O- or SiR'R2O- in which R ', R2, which may be identical or different, represent an alkyl group especially methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, cycloalkyl such as cyclopentyl or cyclohexyl., mono- or bicyclic aryl comprising from 6 to 12 carbon atoms, preferably phenyl. , 9. Copolymer according to one of the preceding claims characterized in that the block A represents at least 30% by weight of the copolymer and preferably between 50 and 95% by weight of the copolymer.   10. Copolymer according to one of the preceding claims characterized in that the average mass number of the block A is between 500 and 100000 and preferably between 2000 and 20000.   11. Copolymer according to one of the preceding claims characterized in that the average mass number of the block B is between 500 and 100000 and preferably between 1000 and 10000.   A formulation comprising: - an aqueous liquid carrier, optionally a vectorized product, being a non-water soluble active ingredient or a non-water soluble composition comprising a water-soluble or non-water-soluble active ingredient, and the copolymer according to one of the preceding claims.   13. Formulation according to claim 12, characterized in that the vectorized product is dispersed in the liquid carrier, in the form of a dispersion of solid particles stabilized by the copolymer, dispersion of liquid droplets stabilized by the copolymer, or dispersion at micelle core of the copolymer, the formulation being at a temperature below the critical lower solubility temperature of the A block. 14. Formulation according to one of claims 12 to 13, characterized in that it is: - a formulation intended to be applied to the skin and / or the hair, on textile fibers, or a hydraulic binder formulation, for example a cementitious formulation (the copolymer is a water repellent), or - a formulation for applications in the field of coatings such as paints, varnishes or adhesives.   15. Use of the formulation according to one of claims 12 to 13 for vectorizing an active ingredient on a surface by applying the formulation on said surface at a temperature below the LCST and increasing the temperature to a temperature above the LCST .