FR2797877A1 - Copolymer with optical brightener, used for whitening textiles, paper and plastics, contains comonomer units to which an optical brightener is attached by covalent bonds - Google Patents

Abstract

Copolymers (CP) consisting of units (A) and units (B), containing 4-30 wt.% of an optical brightener (C) attached to (B) by covalent bonds. Copolymers (CP) consisting of units (A) and units (B), containing 4-30 wt.% of an optical brightener (C) attached to (B) by covalent bonds. Independent claims are also included for: (a) production of (CP) by radical copolymerization of a monomer (A') with a monomer (B') to which (C) is attached by covalent bonds; (b) production of (CP) by making a copolymer containing pendant groups which can react with (C) and then reacting these groups with (C); (c) a polymerizable monomer of formula Ar-CH=CH-pPhe-pPhe-CH=CH-mPhe-OCO-C(CH3)=CH2 (VII) for use in process (a); (d) preparation of a polymerizable monomer of formula Ar'-CH=CH-pPhe-pPhe-CH=CH-mPhe-R<1> (VIII) by coupling a boronic acid of formula Ar'-CH=CH-pPhe-B(OH)2 (IX) with a compound of formula Br-pPhe-CH=CH-mPhe-OH to give a biphenyl derivative of formula Ar'-CH=CH-pPhe-pPhe-CH=CH-mPhe-OH which is then reacted with a compound R<1>H; (e) preparation of a monomer of formula (VIII) in which R<1> is a (meth)acrylamido group, by coupling boronic acid (IX) with a bromo-nitro compound (Br-pPhe-CH=CH-mPhe-NO2), then reducing the product to the corresponding amine and reacting the amine with (meth)acrylic acid. Ar = 3,5-di-tert.-butylphenyl; pPhe = 1,4-phenylene; mPhe = 1,3-phenylene Ar' = 3,5-dialkylphenyl, preferably 3,5-di-tert.-butylphenyl; R<1> = (meth)acryloyloxy.

Description

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OPTICAL BRIGHTENER-BASED COPOLYMERS, THEIR MANUFACTURING AND POLYMERISABLE MONOMER USEFUL FOR THIS MANUFACTURING.

DESCRIPTION Technical area
The present invention relates to copolymers comprising optical brighteners, which can be used in industry, in particular in the textile industry, in the paper industry and in the plastics industry.

State of the prior art
It has already been envisaged to produce polymers and copolymers comprising optical brighteners in order to bleach the polymers and to obtain white products resistant to washing and to solvents, for various applications, in particular for the bleaching of textiles, paper and plastics. , for example for the manufacture of everyday objects such as toys, stationery, etc.

It should be remembered that optical brighteners are optical bleaching agents, consisting of chemical compounds endowed with blue fluorescence, which absorb in the ultra-violet (maximum absorption at a wavelength of less than 400 nm) and re-emit energy by fluorescence in the visible (emission in the blue around 400 nm).

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To avoid their dispersion in various media, these brighteners can be fixed on polymers or copolymers.

Thus, I. Grabchev and T. Philipova have described in Die Angewandte Makromolekulare Chemie 263, 1998,1-4, page 4508 [1], copolymers of styrene and of triazine-stilbene derivatives, or of optical brightener derivatives, comprising 0.5% by weight of triazine-stilbene, which exhibit maximum absorption properties at 338-342 nm and maximum fluorescence properties at 416-422 nm.

T. N. Konstantinova and I. K. Grabchev described in Polymer International 43,1997, pp. 39-44 [2] copolymers of styrene or acrylonitrile with derivatives of an optical brightener, 1,8-naphthalimide, containing 0.1 to 0.3% by weight of this optical brightener.

Copolymers of this type do not exhibit sufficient fluorescence light intensity for certain applications. Also, it was considered to produce optical brightener polymers only from polymerizable optical brightener derivatives such as those of the documents mentioned above, but it was found that their fluorescence emission was particularly poor while the absorption was important, and that this emission was moreover shifted towards the red compared to the optical brightener used.

In addition, it has been observed that most optical brighteners are poorly soluble in organic solvents, which poses certain problems.

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for use in radical polymerization processes.

The present invention specifically relates to copolymers comprising optical brighteners attached to the chain of the copolymer by covalent bonds, which exhibit fluorescence emission of maximum light intensity in the blue-violet region of the visible spectrum and which can be manufactured by processes easy to process from polymerizable monomers soluble in organic solvents.

Disclosure of the invention
According to the invention, the copolymer is formed of units A and of units B comprising an optical brightener C covalently bonded to the units B, and it comprises 4 to 30% by weight of optical brightener C relative to the weight of the total copolymer .

According to the invention, it has thus been found that the light intensity of the fluorescent emission was maximum when the optical brightener content of the copolymer was limited to a precise range.

Indeed, with the optical brightener contents of the copolymers described in references [1] and [2], the fluorescence light intensity is very low. On the other hand, when the optical brightener content of the copolymer exceeds 30% by weight, an extinction or quenching of the fluorescence phenomenon is observed, the latter being particularly low when the polymer is a homopolymer formed.

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only monomer units comprising an optical brightener group.

The optical brightener fixed in this copolymer can be chosen from optical brighteners known and used hitherto for bleaching.

dans laquelle A1 est un groupe aromatique, hétérocyclique ou alcoylène, et A est un atome d'hydrogène ou un groupe alkyle ;
2) des coumarines de formule :

dans laquelle A3 est un groupe hétérocyclique ;
3) des bis(styryl)biphényle de formule :

dans laquelle A4, A5 , A6, A7, B et Bqui peuvent être identiques ou différents, représentent indépendamment un atome d'hydrogène, -S03Na ou un groupe alkyle ; et
4) des dérivés de triazine-stilbène de formule : It is possible in particular to use an optical brightener chosen from the group consisting of:
1) bis (benzoxazol-2-yl) of the formula:

wherein A1 is an aromatic, heterocyclic or alkylene group, and A is a hydrogen atom or an alkyl group;
2) coumarins of formula:

wherein A3 is a heterocyclic group;
3) bis (styryl) biphenyl of formula:

wherein A4, A5, A6, A7, B and B which may be the same or different, independently represent a hydrogen atom, -SO3Na or an alkyl group; and
4) triazine-stilbene derivatives of formula:

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dans laquelle A8, A9, A12 et A13 représentent indépendamment un atome d'hydrogène, un groupe -S03Na ou un groupe phénylamino, dialkylamino ou morpholino, et A10 et A11 représentent indépendamment un atome d'hydrogène ou -S03Na.

wherein A8, A9, A12 and A13 independently represent a hydrogen atom, a -SO3Na group or a phenylamino, dialkylamino or morpholino group, and A10 and A11 independently represent a hydrogen atom or -SO3Na.

In the formulas given above, the aromatic groups used may be groups comprising one or more benzene rings, for example phenyl, biphenyl, substituted phenyl groups or aromatic groups formed from polycyclic aromatic hydrocarbons, such as naphthyl groups. , phenanthryl, anthracenyl, fluoranthenyl, etc.

Heterocyclic groups are hydrocarbon groups, saturated or unsaturated, comprising one or more heteroatoms such as 0, N and S. By way of example of heterocyclic groups, mention may be made of thienyl, furyl, pyranyl, isobenzofuranyl, isobenzothienyl, pyrrolyl groups. , pyridyl, pyrazolyl.

The alkylene groups used can be linear or branched and contain from 3 to 16 carbon atoms.

The alkyl groups which may be used are linear or branched groups, having

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preferably from 1 to 16 carbon atoms. In particular, the tert-butyl group is used.

When in formula (IV), A8, A9, A12 and / or A13 represent a dialkylamino group, the alkyl groups preferably have from 1 to 12 carbon atoms.

By way of example, the optical brightener can correspond to formula (III) in which A and A represent an alkyl group, for example the tert-butyl group, and A, A, B and B represent a hydrogen atom. .

et Areprésente le groupe-tert-butyle. It is also possible to use an optical brightener corresponding to formula (I) in which A represents the group:

and A represents the group-tert-butyl.

It is also possible to use an optical brightener corresponding to formula (IV) in which A10 and A11 represent -SO3Na and A8, A9, A12 and A13 represent the phenylamino group.

In the copolymer of the invention, the units A and B can be derived from various polymerizable monomers of similar or different structures.

Thus, the succession of units A and B can correspond to the backbone of a natural polymer such as cellulose hydroxyethers, polysaccharides, cellulose esters, modified proteins and protein hydrolysates. Preferably, the A

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and B are units of synthetic polymers, for example units derived from acrylic, methacrylic, vinyl, olefinic and / or styrenic monomers.

According to a particular embodiment, the copolymer comprises A units derived from methyl methacrylate and B units derived from the methacrylate of the optical brightener.

dans laquelle x et y sont tels que la proportion massique de groupes azurants optiques C de formule :

représente 4 à 30 % en poids du copolymère total. By way of example, the copolymer can correspond to the overall formula:

in which x and y are such that the mass proportion of optical brightening groups C of formula:

represents 4 to 30% by weight of the total copolymer.

In this formula, units A are formed from methyl methacrylate and units B are from methacrylate from optical brightener. They are distributed randomly in the copolymer chain.

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Preferably, the proportion by weight of optical brightening groups C represents 8 to 10% by weight of the total copolymer.

The copolymers of the invention can be prepared by conventional processes, for example by radical copolymerization of a monomer A ′ and of a monomer B ′ to which the optical brightener C is attached by a covalent bond. This radical copolymerization is generally carried out in organic solution in the presence of a polymerization initiator such as azoisobutyronitrile.

The copolymer of the invention can also be prepared by a process comprising the following steps: a) preparing a copolymer comprising pendant groups capable of reacting with the optical brightener C, and b) reacting the pendant groups with the optical brightener C to fix the latter on the copolymer in an amount such that it represents 4 to 30% of the weight of the modified copolymer.

In this case, the copolymer can also be prepared by radical copolymerization of two monomers, one of which contains the pendant groups.

This polymerization can also be carried out in solution using the same polymerization initiators.

The proportions of monomers brought into contact for the manufacture of the copolymer in the two methods of carrying out the process are such that

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the desired proportion of optical brightener can be obtained in the final copolymer.

A further subject of the invention is a polymerizable monomer, which can be used in the copolymerization process described above, which has the advantage of being more soluble in organic solvents than known optical brighteners.

This polymerizable monomer corresponds to the formula:

dans laquelle A4 et A5 sont des groupes alkyl et R1 représente l'un des groupes suivants :

The invention also relates to a process for the manufacture of polymerizable monomers which can be used for the preparation of the copolymers of the invention, corresponding to the formula:

in which A4 and A5 are alkyl groups and R1 represents one of the following groups:

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dans laquelle A4 et A5 sont tels que définis ci-dessus avec le dérivé bromé de formule :

pour obtenir le composé de formule . which comprises the following steps: 1) coupling of a boronic acid of formula:

in which A4 and A5 are as defined above with the brominated derivative of formula:

to obtain the compound of formula.

A4

2) reaction of the compound of formula (XI) with the compound of formula R H where R1 is as defined above.

Boronic acid of formula (IX) used in this process can be prepared from 4-bromo-3 ', 5'-dialkyl-stilbene by reaction with butyllithium in tetrahydrofuran at -78 C, followed by reaction with B (OBu) 3 from acid hydrolysis.

4-Bromo-3 ', 5'-dialkyl-stilbene can be prepared from the corresponding dialkyl toluene by bromination, followed by reaction with triethylphosphite and then with bromo-4-benzaldehyde.

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dans laquelle A 4 et A sont des groupes alkyle et R2représente l'un des groupes suivants :

qui comprend les étapes suivantes :
1) couplage d'un acide boronique de formule :

dans laquelle A4 et A5 sont tels que définis ci-dessus avec le dérivé bromé de formule :

pour obtenir le composé de formule :

The invention also relates to a process for the manufacture of polymerizable monomers which can be used for the preparation of copolymers of the invention, corresponding to the formula:

in which A 4 and A are alkyl groups and R2 represents one of the following groups:

which includes the following steps:
1) coupling of a boronic acid of formula:

in which A4 and A5 are as defined above with the brominated derivative of formula:

to obtain the compound of formula:

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2) reduction of the compound of formula (XXIV) to obtain the compound of formula:

3) reaction of the compound of formula (XXV) with acrylic acid or methacrylic acid.

Other characteristics and advantages of the invention will emerge more clearly on reading the following description of exemplary embodiments, of course given by way of illustration and not by way of limitation.

Brief description of the drawings
FIG. 1 illustrates the UV-visible absorption spectra of the various copolymers based on optical brightener, in film form.

FIG. 2 illustrates the fluorescence emission spectra of the various copolymers of FIG. 1, in the form of a film.

FIG. 3 illustrates the variations in the light intensity reemitted as a function of the molar fraction of monomer B with optical brightener of the copolymer.

FIG. 4 illustrates the fluorescence spectra of the copolymers of FIG. 1, in the form of powders.

Figure 5 illustrates the variations in the re-emitted light intensity as a function of the

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mass proportion of monomer B with optical brightener of the copolymer.

Detailed description of the embodiments
The examples which follow illustrate the synthesis of a polymerizable monomer comprising an optical brightener C, which can be used for the manufacture of copolymers in accordance with the invention, and the manufacture of copolymers from this monomer.

a) synthèse du 4-bromo-3',5'-ditert-butylstilbène de formule :

Example 1: Preparation of the methacrylate of formula:

a) synthesis of 4-bromo-3 ', 5'-ditert-butylstilbene of formula:

3C -7

This synthesis corresponds to the following reaction scheme:

3C -7

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- Preparation of 3,5-ditertbutylbenzyl bromide (XIV).

In a 500 ml flask containing 50 g (0.25 mol) of 3,5-ditert-butyltoluene (XIII) and 160 ml of carbon tetrachloride, a solution of 13 ml of bromine (i.e. 40.5 g) is poured. / 0.25 mol) in 40 ml of CC14 over a period of one hour. Stirred at room temperature for 12 hours, then the solvent is evaporated off. The residual viscous yellow liquid is distilled under vacuum (1 mm / Hg). 48 g of a colorless liquid corresponding to compound (XIV) are obtained, the yield is 68%.

- Preparation of ethyl 3,5-ditertbutylbenzylphosphonate (XV).

47.4 g (0.17 mole) of 3,5-ditert-butylbenzyl bromide (XIV) are heated with 31.5 g (0.19 mole) of triethyl phosphite at 160 C (gradually) for 5 hours ( then at 20 C for 18 hours). Volatiles are removed in vacuo but the product is not distilled due to its high boiling point. 54 g of a pale yellow viscous liquid consisting of compound (XV) are obtained; the yield is 94%.

- Preparation of 4-bromo-3 ', 5'-ditertbutylstilbene (XII).

3.6 g (20 mM) of 4bromobenzaldehyde and 6.8 g (20 mM) of ethyl 3,5ditertbutylbenzylphosphonate (XV) are dissolved in 10 ml of distilled N, N-dimethylformamide. The reaction flask is immersed in a bath of fresh water. We

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then flows 22 ml of a solution of 1M potassium tert-butoxide in THF (22 mM). The mixture is stirred for 22 hours at room temperature. The reaction mixture is hydrolyzed with 500 ml of deionized water. The precipitated solid is filtered off, rinsed and then crystallized from acetonitrile (45 ml for 6.9 g of crude product).

4.88 g of beige crystals of compound (XII) are obtained.

The yield is 66%. b) synthesis of 3 - ((4-bromophenyl) vinyl) phenol of formula (XVI):

This synthesis corresponds to the following reaction scheme:

A mixture of 100 g (0.4 mole) of 4bromobenzyl bromide (XVII) and 69.95 g (0.4 mole) of triethyl phosphite is heated at 110 ° C. for 10 hours. The product is then distilled under vacuum (approximately 1 mm Hg). 110 g of a

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colorless liquid (XVIII); the yield is 95%.

Proton NMR control.

- Preparation of 3 - ((4bromophenyl) vinyl) phenol (XVI).

2.57 g (20 mM) of 3hydroxybenzaldehyde and 6.4 g (52 mM) of ethyl 4bromobenzylphosphonate (XVIII) are dissolved in 10 mL of dry tetrahydrofuran. The reaction flask is immersed in a bath of fresh water. 105 ml of a 0.4 M potassium tert-butoxide solution in THF (42 mM) are then poured. The mixture is stirred for 22 hours at room temperature. 12 ml of 6N sulfuric acid (72 mM) are then added, followed by 20 ml of water. The solvent is evaporated off in vacuo (20 mm Hg), the solid which appears is filtered off. The product is purified by liquid column chromatography (silica, eluent: dichloromethane), then crystallized from 15 ml of toluene. 4 g of product (XVI) are obtained. Melting point 139-40 C.

Yield: 73%. c) Preparation of boronic acid of formula (XIX):

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- Préparation de l'acide 4-((3,5-ditertbutylphényl)vinyl)phénylboronique. This preparation is carried out from 4-bromo-3 ', 5'-ditert-butyl-stilbene of formula (XII), according to the following reaction scheme:

- Preparation of 4 - ((3,5-ditertbutylphenyl) vinyl) phenylboronic acid.

7.57 g (20 mMole) of 4-bromo-3 ', 5'ditertbutylstilbene (XII) are dissolved in 80 ml of anhydrous tetrahydrofuran. The reaction medium is cooled to -70 ° C. and 10 mL of a solution of 2.2 M n-butyllithium in hexane (ie 22 mM) is poured over 15 minutes. After stirring for one hour at low temperature, 6 ml (22 mMole) of butyl borate dissolved in 2 ml of dry THF are charged. The temperature is allowed to return slowly to room temperature with stirring for 16 hours. Hydrolysis is carried out with 40 ml of water, then 12 ml of 6N sulfuric acid (72 mMole), the solvent is evaporated off in vacuo, and the organic phase which has appeared is decanted. The residual borate is removed under vacuum in a desiccator.

6.24 g of a light beige solid (compound (XIX)) are obtained, yield: 93%. d) Preparation of the precursor of formula (XX): @

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by coupling the boronic acid of formula (XIX) and the brominated derivative of formula (XVI). This coupling is carried out as follows.

2.11 g (7.7 mMole) of 3 - ((4-bromophenyl) vinyl) phenol (XVI), 0.35 g (0.3 mMole) of tetrakis (triphenylphosphine) palladium ( 0) in 25 mL of dry 1,2dimethoxyethane. The reaction medium is brought to 70 ° C. After 10 minutes, 2.82 g (8.4 mMole) of 4 - ((3,5-diterbutylphenyl) vinyl) phenylboronic acid (XIX) are charged. Five minutes later, 16 ml of 2M potassium carbonate solution are added. Heating is maintained for 8 hours. After cooling, ethyl ether and ethyl acetate are added, then the reaction medium is acidified. Extracted in a separatory funnel and the organic phase is recovered.

The crude product is crystallized from 150 ml of toluene. The beige-yellow solid obtained is drained and dried. 2.17 g (and 0.79 g by chromatography of mother liquors) of compound (XX) are obtained. Overall yield (crystallization + chromatography): 79%. e) Esterification of the precursor of formula (XX) with methacrylic acid.

This reaction corresponds to the following reaction scheme:

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2.17 g (4.5 mMole) of the brightener (3- [4'- (3,5-ditertbutylphenylvinyl) biphenyl-4-yl-vinyl] phenol (XX) and 0.6 g (7 mMole) d methacrylic acid are dissolved at room temperature in 40 ml of dry dichloromethane 0.12 g (1 mMole) of 4-dimethylaminopyridine is then added, then 1.21 g (5.9 mMole) of N, N'-dicyclohexylcarbodiimide. The mixture is stirred overnight, the N, N'-dicyclohexylurea formed is filtered off, the solvent is evaporated off and the crude product is taken up in 30 ml of boiling cyclohexane. After cooling, the solid which appears is drained. It is purified by liquid chromatography (silica, elution: dichloromethane / cyclohexane, 50/50 by volume).

2.29 g of white product are obtained, the methacrylate of formula (VII). A pale lemon yellow allotropic form appears spontaneously after some time.

Yield: 93%.

Example 2 Preparation of copolymers from the methacrylate of formula (VII).

In this example, different proportions of methacrylate of formula (VII) and of methyl methacrylate are used to obtain a copolymer by radical polymerization in solution.

This reaction is carried out in dry toluene at a temperature of 70 ° C., using azoisobutyronitrile as a free radical initiator.

It corresponds to the following reaction scheme:

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In this copolymer, the units A and B corresponding respectively to the methyl methacrylate and methacrylate monomers of the optical brightener are distributed in the chain at random, and the x and y contents are such that one obtains copolymers having different levels of optical brightener. Table 1 below illustrates the copolymers obtained which correspond to different levels by mass of optical brightener methacrylate and therefore of optical brightener.

In the case of the copolymer containing 9% by weight of brightener methacrylate, the procedure is as follows.

The solution of 0.13 g (0.23 mmol) of brightener methacrylate (VII), 1.3 g (13 mmol) of distilled methyl methacrylate (XXI), 3.2 mg of distilled methyl methacrylate (XXI) is heated to 70 ° C. 'AIBN (2,2' - (azobisisobutyronitrile)) in 15 ml of solvent (N, N-dimethylformamide or toluene). After 48 hours, the mixture is left to cool, and the polymer is precipitated by pouring

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the solution in 95% ethanol dropwise. The solid is drained, dried and then redissolved in toluene for a second precipitation in ethanol. 1.2 g of white amorphous powder are then obtained (yield 84%).

The procedure is similar for the other copolymers.

It is verified by proton nuclear magnetic resonance spectrometry that the molar fractions of units B in the copolymers obtained correspond practically to those which were used.

Example 3
In this example, the properties of copolymers 1 to 5 obtained in Example 2 are studied. To carry out this study, the copolymers are put in the form of films by the spin-coating method, by depositing the polymer. by centrifugation from a solution of the copolymer in 1,1,2-trichloroethane. The conditions for making films on the turntable are as follows:

<tb>
<tb> Acceleration <SEP> Speed <SEP> Duration
<tb> (revolutions / min / s) <SEP> (revolutions / min)
<tb> (s)
<tb> 600 <SEP> 1200 <SEP> 15
<tb> 2000 <SEP> 3000 <SEP> 50
<tb>

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For each of the copolymers, a 33 g / l solution is prepared in commercial 1,1,2-trichloroethane, then, after stirring, the solution is filtered through a 5 μm Millex Millipore filter and the spin coating is then carried out on a previously cleaned glass slide. An annealing is carried out for 10 minutes at 80-100 C to remove traces of residual solvent. The films are then stored away from light.

The thickness of the films is first determined on a DEKTAK profilometer. The results obtained are as follows:

<tb>
<tb> Copolymer <SEP> Thickness
<tb> 1 <SEP> 0.19 <SEP> m
<tb> 2 <SEP> 0.17 <SEP> m
<tb> 3 <SEP> 0.18 <SEP> m
<tb> 4 <SEP> 0.16 <SEP> m
<tb> 5 <SEP> 0 <SEP>, <SEP> 21 <SEP> pm
<tb>

The UV-visible absorption spectra of the films are then determined on a Perkin-Elmer Lambda 19 spectrophotometer between 300 and 800 nm.

These spectra are represented in FIG. 1 which illustrates the optical density as a function of the wavelength (in nm). In this figure, it can be seen that the highest absorption is obtained with copolymer n 5 which comprises 60% by mass of units B of the optical brightener monomer, which is explained by the higher proportion of active molecule. On the other hand, the optical density decreases when the optical brightener content of the copolymer decreases. We thus notice that the

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optical density is directly proportional to the optical brightener concentration according to Beer's law DO = s 1 c, where c is the optical brightener concentration, 1 the optical path length and s the molar absorption coefficient.

Thus, the greater the proportion of optical brightener, the higher the optical density, which is in accordance with the expected effect.

The fluorescence emission spectra of the films were also determined on a Hitachi F-4500 fluorescence spectrophotometer under the following conditions:
Excitation wavelength: 350 nm
Slit (exc / em): 2.5 nm / 2.5 nm
Scanning speed: 240 nm / min
PMT voltage: 700 Volts
These spectra are illustrated in FIG. 2 where it can be seen that the re-emitted light intensity is the highest in the case of the copolymer 2 comprising 9% by mass of unit B with optical brightener and that it is lowest in the case of the copolymer. the case of copolymer n 5 comprising 60% by mass of unit B with optical brightener.

An inhibition or quenching of fluorescence is thus observed when the density of fluorescent sites is very high.

Thus, the optimum fluorescence emission corresponds to a proportion of optical brightener of 5 to 20% by mass, the copolymer n 3 which comprises 20% of active monomers, has a higher emission so

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significant to that of the copolymer with 5% active monomers.

FIG. 3 illustrates these results in the form of the variation of the maximum re-emitted light intensity as a function of the molar proportion in pattern B.

In this figure, a quenching phenomenon clearly appears as soon as the quantity of pattern B with optical brightener exceeds 20%.

The fluorescence emission spectra of the copolymers in powder form were also carried out under the following conditions:
Excitation wavelength: 350 nm
Slit (exc / em): 2.5 nm / 2.5 nm
Scanning speed: 240 nm / min
PMT voltage: 950 Volts
FIG. 4 illustrates the fluorescence spectra thus obtained. These spectra are similar to those in Figure 2.

Thus, the copolymer n 2 exhibits the greatest fluorescence emission.

This figure also shows the spectrum obtained with polymer No. 6 comprising 100% of unit B obtained by radical polymerization of the monomer of formula (VII) under the same conditions.

It is noted that this copolymer n 6 exhibits the lowest fluorescence emission.

In addition, we notice a shift of the maximum emission wavelength towards the red (towards the right) when the rate of active B units increases,

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or when the quenching phenomenon appears. The spectrum then flattens sharply.

FIG. 5 illustrates the variation of the maximum light intensity re-emitted as a function of the rate of active B units. A curve very similar to that obtained in the case of samples in film form is obtained, with an optimum for a rate of B units of the order of 8 to 9%, i.e. 6 to 8% by weight of optical brightener C .

Comparative Examples 1 to 3
In these examples, several samples are prepared consisting of an inert matrix of polymethyl methacrylate (PMMA) in which an optical brightener is incorporated in an amount of 10% by weight.

et A2 représentant le groupe tert-butyle. For this purpose, three solutions of 33 g / 1 of commercial polymethyl methacrylate (average mass 25,000) in 1,1,2-trichloroethane are prepared and 10% by mass of one of the following optical brighteners are added thereto: - the methacrylate of the optical brightener of formula (VII) described above, - the commercial optical brightener TINOPAL SOP which corresponds to the formula (IV) given above with A10 and A11 representing -S03Na and A8, A9, A12 and A13 representing the phenylamino group, and - the commercial optical brightener UVITEX which corresponds to formula (I) above with A representing:

and A2 representing the tert-butyl group.

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Each solution is filtered through a 5 μm Millex filter, then deposited with a spinner on glass slides and annealed at 80 ° C. for 10 minutes. The following polymer films are thus obtained:

<tb>
<tb> Polymer <SEP> n 7 <SEP> PMMA <SEP> + <SEP> 10 <SEP>% <SEP> of brightener <SEP> optical <SEP> (VII)
<tb> Polymer <SEP> n 8 <SEP> PMMA <SEP> + <SEP> 10 <SEP>% <SEP> of <SEP> TINOPAL <SEP> SOP
<tb> Polymer <SEP> n 9 <SEP> PMMA <SEP> + <SEP> 10 <SEP>% <SEP> of UVITEX
<tb>

The UV-visible absorption spectra of these films are obtained on a Perkin Elmer spectrophotometer between 300 and 600 nm. The maximum optical densities are given in Table 2.

In this Table 2, we have also reported the results obtained with a film of polymer 6, homopolymer of compound (VII), prepared in the same way. Thus, we notice the strong absorption of the polymer film 6 compared to the other films and a spectral shift towards the red (to the right) for the films of polymers 8 and 9 with the TINOPAL SOP and UVITEX compounds.

The emission spectra of these films as well as that of polymer film 6 are now determined on a HITACHI F-4500 spectrofluorimeter under the following conditions:
Excitation wavelength: 340 nm
Slit (ex / en): 2.5nm / 2.5nm
Scanning speed: 240 nm / min
PMT voltage: 700 Volts
Response 0.5 s
The results obtained are given in Table 3.

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These results show that the film of polymer 6 (homopolymer of compound VII) has a very low fluorescence emitted and that the film of polymer 7 has a greater fluorescence emission than that of the films of polymers 8 and 9.

The fluorescence emission of polymer n 6, of TINOPAL SOP and UVITEX molecules and of molecule (VII), in powder form, was also studied in order to compare them with copolymer n 2, also in powder form. The fluorescence spectra were determined under the following conditions:
Excitation wavelength: 350 nm
Slit (ex / em): 1 nm / 1 nm
Scanning speed: 240 nm / min
PMT voltage: 950 Volts
The results obtained are given in Table 4 attached.

It is thus noted that the re-emitted light intensity is very intense for the samples of powder of copolymer 2 and of the TINOPAL SOP and UVITEX molecules compared to the samples of powder of the polymer 6 and of the molecule (VII), and that the length of emission wave is shifted towards blue for the sample of copolymer 2 compared to the samples of powder of the molecules TINOPAL SOP and UVITEX.

These comparative examples thus prove the superiority of the optical brightener MA of formula (VII) over the commercial products UVITEX and TINOPAL SOP.

<Desc / Clms Page number 28>

According to the invention, still other advantages are obtained by fixing this brightener on the polymer chain by a covalent bond.

In fact, this avoids the possibility of releasing the optical brightener into the surrounding medium, which makes it compatible with various hydrophilic or hydrophobic media. This fixation thus makes it insensitive to chemical reactions and makes it compatible with other dyes, if necessary.

Finally, another advantage of the invention is to limit the amount of optical brightener in the product (to values of 8-10% by mass) while obtaining the maximum effect of reemitted fluorescence. This makes it possible to reduce the cost of the products in which this optical brightener is incorporated.

References cited.

[1]: I. Grabchev and T. Philipova, Die Angewandte Makro molekulare Chemie 263,1998, 1-4, page 4508.

[2]: T. N. Konstantinova and I. K. Grabchev, Polymer International 43,1997, pp. 39-44.

<Desc / Clms Page number 29>

Table 1

<tb>
<tb> Copolymer <SEP>% <SEP> in <SEP> weight <SEP> of <SEP> Pattern <SEP> A <SEP>% <SEP> in <SEP> weight <SEP> of <SEP> Pattern <SEP > B <SEP>% <SEP> in <SEP> weight <SEP>% <SEP> in <SEP> mmol
<tb> (% <SEP> in <SEP> mole) <SEP> (% <SEP> in <SEP> mole) <SEP> of <SEP> brightener <SEP> determined
<tb> (methacrylate <SEP> of <SEP> methyl <SEP> (methacrylate <SEP> optical <SEP> by <SEP> NMR
<tb> of optical brightener)
<tb> A <SEP> B
<tb> 1 <SEP> 95 <SEP> (99) <SEP> 5 <SEP> (1) <SEP> 4.23 <SEP> 99 <SEP> 1
<tb> 2 <SEP> 91 <SEP> (98) <SEP> 9 <SEP> (2) <SEP> 7,6 <SEP> 97 <SEP> 3
<tb> 3 <SEP> 80 <SEP> (95.5) <SEP> 20 <SEP> (4.4) <SEP> 17 <SEP> 95 <SEP> 5
<tb> 4 <SEP> 65 <SEP> (91) <SEP> 35 <SEP> (9) <SEP> 29.6 <SEP> 90 <SEP> 1 (
<tb> 5 <SEP> 40 (79) <SEP> 60 <SEP> (21) <SEP> 50.79 <SEP> 73 <SEP> 27
<tb>
Table 2

<tb>
<tb> Polymer <SEP> Length <SEP> max <SEP> DO <SEP> max
<tb> 6. <SEP> homopolymer <SEP> of <SEP> (VII) <SEP> 345 <SEP> 2,3
<tb> 7. <SEP> PMMA <SEP> + <SEP> 10 <SEP>% <SEP> of <SEP> (VII) <SEP> 350 <SEP> 0.32
<tb> 8. <SEP> PMMA <SEP> + <SEP> 10 <SEP>% <SEP> TINOPAL <SEP> SOP <SEP> 360 <SEP> 0.34 <SEP>
<tb> 9. <SEP> PMMA <SEP> + <SEP> 10 <SEP>% <SEP> UVITEX <SEP> 360 <SEP> 0.30
<tb>

<Desc / Clms Page number 30>

Table 3

<tb>
<tb> Intensity <SEP> light
<tb> Sample <SEP> in <SEP> form <SEP> of <SEP> film <SEP>#max<SEP> of transmission <SEP> reissued
<tb> (nm) <SEP> (u. <SEP> arb.)
<tb> 6. <SEP> Homopolymer <SEP> of <SEP> (VII) <SEP> 440 <SEP> 360
<tb> 7. <SEP> PMMA <SEP> + <SEP> 10 <SEP>% <SEP> of <SEP> (VII) <SEP> 405-425 <SEP> 1800-2030
<tb> 8. <SEP> PMMA <SEP> + <SEP> 10 <SEP>% <SEP> TINOPAL <SEP> SOP <SEP> 450 <SEP> 435
<tb> 9. <SEP> PMMA <SEP> + <SEP> 10 <SEP>% <SEP> UVITEX <SEP> 420-440 <SEP> 325-525
<tb>
Table 4

<tb>
<tb> Intensity <SEP> light
<tb> Sample <SEP> in <SEP> form <SEP> of <SEP> powder <SEP>#max<SEP> of emission <SEP> reissued
<tb> (nm) <SEP> (u, <SEP> arb. <SEP>)
<tb> 2. <SEP> Copolymer <SEP> (V) <SEP> with <SEP> y <SEP> 0.02 <SEP> 434 <SEP> 2822
<tb> 6. <SEP> Homopolymer <SEP> of <SEP> (VII) <SEP> 446 <SEP> 1395
<tb> 7bis. <SEP> (VII) <SEP> 444 <SEP> 270
<tb> 8bis. <SEP> TINOPAL <SEP> SOP <SEP> 446 <SEP> 1248
<tb> 9bis. <SEP> UVITEX <SEP> 453 <SEP> 2123
<tb>

Claims (16)

1. Copolymer formed from units A and from units B comprising an optical brightener C covalently bonded to the units B, said copolymer comprising 4 to 30% by weight of optical brightener C relative to the weight of the total copolymer. 2. Copolymer according to claim 1, wherein the optical brightener is selected from the group 1) bis (benzoxazol-2-yl) of the formula:

wherein A1 is an aromatic, heterocyclic or alkylene group, and A is a hydrogen atom or an alkyl group; 2) coumarins of formula:

wherein A3 is a heterocyclic group; 3) bis (styryl) biphenyl of formula:

<Desc / Clms Page number 32> wherein A, A, A12 and A independently represent a hydrogen atom, a -SO3Na group or a phenylamino, dialkylamino or morpholino group, and A10 and A11 independently represent a hydrogen atom or -SO3Na.

4) triazine-stilbene derivatives of formula: wherein A4, A, A, A, B and B which may be the same or different, independently represent a hydrogen atom, -SO3Na or an alkyl group; and 3. Copolymer according to claim 2, in which the optical brightener corresponds to formula (III) in which A and A5 represent an alkyl group and A6, A7, B1 and B2 represent a hydrogen atom. 4. A copolymer according to claim 3, wherein A and A represent the tert-butyl group. 5. Copolymer according to claim 2, in which the optical brightener corresponds to formula (I) in which A represents the group:

and A represents the group-tert-butyl. 6. Copolymer according to claim 2, in which the optical brightener corresponds to formula (IV). <Desc / Clms Page number 33> wherein A10 and A11 represent -S03Na and A8, A9, A12 and A13 represent the phenylamino group. 7. Copolymer according to any one of claims 1 to 6, in which the units A and B are units derived from acrylic, methacrylic, vinyl, olefinic and / or styrenic monomers. 8. Copolymer according to claim 7, wherein the unit A is derived from methyl methacrylate and the unit B is derived from the methacrylate of the optical brightener. 9. Copolymer according to claim 8, which corresponds to the overall formula:

in which x and y are such that the mass proportion of optical brightening groups C of formula:

represents 4 to 30% by weight of the total copolymer. 10. The copolymer according to claim 9, in which the proportion by mass of brightening groups <Desc / Clms Page number 34> optical C represents 8 to 10% by weight of the total copolymer. 11. Process for preparing a copolymer according to any one of claims 1 to 10, which comprises the radical copolymerization of a monomer A 'and of a monomer B' to which the optical brightener is attached by a covalent bond. vs. 12. Process for preparing a copolymer according to any one of claims 1 to 10, which comprises the following steps: a) preparing a copolymer comprising pendant groups capable of reacting with the optical brightener C, and b) reacting the pendant groups with the optical brightener C to fix the latter on the copolymer in an amount such that it represents 4 to 30% of the weight of the modified copolymer. 13. Polymerizable monomer usable in the process of claim 11 corresponding to the

formula: \ / formula: 0 o (VII) \ J / ~ \ -V = \ # X = J (VU) 14. A process for manufacturing a polymerizable monomer of formula:

<Desc / Clms Page number 35>

to obtain the compound of formula:

in which A4 and A are as defined above with the brominated derivative of formula:

1) coupling of a boronic acid of formula: which includes the following steps:

in which A and A are alkyl groups and R represents one of the following groups: <Desc / Clms Page number 36> 2) reaction of the compound of formula (XI) with the compound of formula R1H where R1 is as defined above. 15. The method of claim 14, wherein A4 and A5 represent the tert-butyl group and R represents:

16. A process for manufacturing a polymerizable monomer of formula:

in which A and A are alkyl groups and R represents one of the following groups:

which includes the following steps: 1) coupling of a boronic acid of formula:

<Desc / Clms Page number 37>

to obtain the compound of formula:

in which A4 and A5 are as defined above with the brominated derivative of formula:

2) reduction of the compound of formula (XXIV) to obtain the compound of formula: 3) reaction of the compound of formula (XXV) with acrylic acid or methacrylic acid.