EP0441675B1 - Polymeric material grafted with phosphate-containing grafts and use - Google Patents

Description

The present invention relates to a polymeric material, in particular textile, on the polymer structure of which have been implanted by the technique of grafting chains with repeating patterns, called grafts. It relates more particularly to a grafted polymeric material of which at least certain grafts are made up of the succession of phosphate patterns, as well as various uses of this material.

The grafting technique is well known. It consists, for example, of activating a polymeric material and then bringing the activated material into contact with a solution of a polymerizable monomer under very precise temperature and duration conditions. The activation has the effect of creating radical sites on the material, from which the polymerization reaction of the monomer develops.

In most cases, grafting allows the characteristics specific to the starting material to be preserved while giving it new characteristics due to the presence of grafts. In particular, this technique has been used to modify the dye affinity of a textile or to give a material ion-exchange properties. In each case, it is necessary to determine the polymerizable monomer suitable for giving the grafted material the desired properties.

The aim which the applicant has set for himself is to propose a grafted polymer material which can meet a large number of different uses.

dans laquelle R₁ est choisi parmi le groupe constitué par H et les alkyles, R₂ est choisi parmi le groupe des alkylènes et des oxydes et/ou polyoxydes d'alkylènes, et R₃⁺ et R₄⁺ sont soit distincts l'un de l'autre, chacun étant choisi parmi le groupe constitué par H⁺ , les ions métalliques monovalents, les cations comportant N⁺, soit confondus et dans ce cas R₃R₄²⁺ est un ion métallique divalent.This object is achieved by the grafted polymeric material according to the invention, in which at least certain grafts are made up of a succession of phosphate units of formula:

in which R₁ is chosen from the group consisting of H and alkyls, R₂ is chosen from the group of alkylene and alkylene oxides and / or polyoxides, and R₃⁺ and R₄⁺ are either distinct from each other , each being chosen from the group consisting of H⁺, the monovalent metal ions, the cations comprising N⁺, either together and in this case R₃R₄²⁺ is a divalent metal ion.

To the knowledge of the applicant, if the phosphate monomers are known in themselves, they have never been used in a grafting reaction to give a grafted polymeric material according to the invention, which has multiple uses.

According to a first use, R₃⁺ and R₄⁺ are H⁺ and the polymeric material can be used as an ion exchanger in a medium which can have an extreme pH, either very acid (pH 0) or very alkaline (pH 12). The phosphated termination (-PO₃ H₂) of the graft motif has the particularity of having cation exchange properties, with a strong function and a weaker function, and also complexing properties with respect to metal ions. divalent.

According to a second use, R₃⁺ and R₄⁺ or R₃R₄²⁺ are chosen from metal ions having recognized antiseptic properties, such as Ag⁺, Zn²⁺, Cu²⁺, Sn²⁺, Hg²⁺ or from antiseptic molecules in the form of cations , in particular from the family of quaternary ammoniums and chlorhexidine, and the polymeric material can be used as an antiseptic material in a medium whose pH can be between 0 and 12. If the grafted polymeric materials with antiseptic activity were known, they exhibited l 'major drawback of not being able to be washed under normal conditions at alkaline pH; the aforementioned material of the invention removes this dissatisfaction.

According to a third use, R₃R₄²⁺ is Ca²⁺, the material is based on a chemically and biologically inert polymer, and it can be used as a bone substitute. For example the material is polypropylene in fibrous form, and the rate grafting is greater than 20%.

According to a fourth use, the material is based on cellulose, the grafting rate being greater than 20% and it can be used as a composite material without binder.

According to a fifth use, the grafting rate being greater than 20%, the grafted polymeric material has flame retardant properties.

According to a sixth use, the grafted polymeric material has an appearance which is similar to that of ivory. For this, the material is in fibrous form, the grafting rate is greater than 20%, R₃R₄²⁺ is a cation preferably chosen from the family of alkaline earths. Preferably, it comprises in the fibrous mass a compatible mineral filler, for example kaolin powder.

In the preferred version of the graft polymeric material of the invention, R₁ is CH₃ and R₂ is the group (CH₂ - CH₂).

dans laquelle R₁ est choisi parmi le groupe constitué par H et les alkyles et R₂ est choisi parmi le groupe des alkylènes et des oxydes et/ou polyoxydes d'alkylène.It is another object of the invention to claim a process for producing the abovementioned graft polymeric material. This process comprises a step of grafting the polymeric material with at least one ethylenic ester of phosphoric acid of formula:

in which R₁ is chosen from the group consisting of H and alkyls and R₂ is chosen from the group of alkylene and alkylene oxides and / or polyoxides.

Other characteristics and advantages will appear on reading the description which will be given of several examples of embodiment and use of polymeric materials with phosphate grafts, illustrated by the single figure which is a schematic perspective representation of an object in form for purification made from polymeric material with phosphate grafts.
1st example. The polymeric material is a polypropylene fabric. It is subjected to an electronic irradiation of 10kGy, then immersed in a solution of ethylene glycol phosphate methacrylate (MAEGP) containing from 0.5 to 1g / l of copper sulphate to delay the homopolymerization. The MAEGP solution is deoxygenated by bubbling nitrogen through it. The assembly is then heated at 100 ° C for 3 hours.

dans lequel P₁ est le poids du matériau greffé et P_o son poids avant greffage.

Table 1 below gives the values of the grafting rate (A) and the graft fixing capacity (B) as a function of the concentrations of the impregnation solution in MAEGP (C₁) and in copper sulfate (C₂) . The grafting rate Tg (A) is measured after extraction, it is equal to:

in which P₁ is the weight of the grafted material and P _o its weight before grafting.

The values given for the grafting rate (A) are average values over ten tests, with very good reproducibility (difference at most of 2%).

This first example illustrates the possibility of obtaining with the MAEGP very high grafting rates, leading to high fixing capacities (B), both in exchange for ions and in complexation.

It should also be noted that the MAEGP solution is obtained by simple dilution of a 76% concentrated primary solution which is kept during storage without special precautions other than the addition of 200 ppM of stabilizers.
2nd example. The textile material is cotton fabric. The grafting operation is done by impregnating a 30% solution of MAEGP, by wringing out the impregnated tissue such that the take-up rate is 100%, then irradiation of the impregnated material in an inert medium under vacuum.

Various tests have been carried out, using radiation doses varying between 10 and 30 kGy. The grafting rates obtained are almost constant, being between 15.1 and 17% whatever the dose practiced.
3rd example. The textile material is a nonwoven containing 80% viscose and 20% polyester. The grafting conditions are the same as for Example 2. The grafting rate is 17.4 for doses of 10 and 20 kGy.

   Ces matériaux sont aptes à échanger et complexer des ions métalliques connus pour leur action antiseptique, tels que l'argent, le cuivre, le zinc, l'étain, le mercure, dans des limites de concentration qui dépendent de la capacité de fixation du matériau greffé.In addition, tests have been carried out with irradiation in the presence of air, and no longer in an inert medium. The grafting rate obtained was 12.8% for irradiation at 10 kGy and 12.9% for irradiation at 20 kGy.
4th example. The materials grafted according to Examples 1,2 and 3 above have grafts having repeating units of the general formula:

These materials are capable of exchanging and complexing metal ions known for their antiseptic action, such as silver, copper, zinc, tin, mercury, within concentration limits which depend on the fixing capacity of the material. graft.

Complexation is almost immediate, by a simple impregnation, padding of grafted material in a bath containing the different metal salt (s).

By acting on the concentrations of metal ions, and on the mode of application in a single bath or in successive baths, it is possible to obtain a material having a spectrum of modular antiseptic activity, depending on the metal ion (s) attached. (R₃⁺, R₄⁺ or R₃R₄²⁺) and their concentration.

The aforementioned materials (examples 1 to 4) are perfectly stable from very acidic pHs (pH 0) to basic pHs (pH 12) corresponding to the usual washing media.

avec n compris entre 7 et 18, par exemple le cation correspondant au colorant vert malachite de formule générale :

par exemple un cation dérivé de la quinoléine, de formule générale:

par exemple un cation de chlorhexidine, de formule générale :

5° exemple. Dix feuilles de papier de 250 g/m² sont imprégnées par une solution à 50% en MAEGP, foulardées en sorte que le taux d'emport soit d'environ 100%, puis placées dans un emballage étanche. On crée dans l'emballage un vide primaire jusqu'à atteindre la tension de vapeur d'eau à température ambiante soit environ 20mm de mercure avant de sceller l'emballage. L'ensemble est irradié sous rayonnement ionisant γ, jusqu'à atteindre une dose de 10kGy (1MRad).What has just been said for the metal ions known for their antiseptic action is also true for certain antiseptic molecules in cationic form, in particular the molecules of the family of quaternary ammoniums, for example the benzalkonium cation of general formula:

with n between 7 and 18, for example the cation corresponding to the malachite green dye of general formula:

for example a cation derived from quinoline, of general formula:

for example a chlorhexidine cation, of general formula:

5th example. Ten sheets of paper of 250 g / m² are impregnated with a 50% MAEGP solution, padded so that the take-up rate is around 100%, then placed in a sealed packaging. A primary vacuum is created in the packaging until the vapor pressure of water at room temperature is reached, that is to say about 20mm of mercury before sealing the packaging. The whole is irradiated under ionizing radiation γ, until reaching a dose of 10kGy (1MRad).

The grafted cellulosic material which is obtained has a compact and homogeneous structure, to the point that the various constituent layers of the ten initial sheets can no longer be separated.

Thus, a complex material was produced, based on cellulose and with a high content of phosphate patterns, without using a binder.
6th example. Reading example 5 above, it is understood that it is very easy to shape the starting polymeric materials and to produce objects from grafted, compact polymeric materials, keeping the imposed shape.

A particularly advantageous application of this possibility lies in the production of ion exchange / complexing objects, which can be used directly, without the usual equipment such as filtration equipment or ion exchange column. These objects will for example have the shape of a strainer, a diffuser or a filter sleeve, in particular conical.

There is shown in the single figure an object 1 of this type. After 100% impregnation of MAEGP, a sheet 2 of paper was rolled up on itself and partly around the end 3 of a cylindrical tube 4. The extreme part of said end 3, covered by the sheet 2, is pierced with several orifices 5.

The assembly thus formed is placed in a sealed package and undergoes the same treatment as that described in Example 5 above. After grafting, a compact object 1 is obtained which is directly usable as an ion / complexing exchanger. The water to be purified is introduced through the free end 6 of the tube 4, according to arrow F. It diffuses through the terminal orifices 5 into the body 7 of the exchanger; the bodies dissolved in the ionic state are retained by ion exchange or complexation and the water which leaves the object 1 according to the arrows G is purified water.

In the above embodiment, the thickness of the winding was 1 cm and the flow rate observed under 0.5 bar of pressure was perfectly compatible with the usual processes of separation techniques of the purification, purification, separation of species soluble.

It should be noted that, all the phosphate monomer (MAEGP) being polymerized, its overall mass reaches 50% by weight of the cellulose. The object 1 obtained is perfectly stable, forming a homogeneous whole.
7th example. Polypropylene fibers are homogeneously distributed in a compressible temporary mold and impregnated with a solution of MAEGP in an amount and in a concentration such that there is no excess. The whole is exposed to gamma radiation (cobalt source for example) so as to deliver a dose of 10kGy to the entire product. The operation takes place at room temperature or, better, at 80 ° C. so as to increase the diffusion of the monomer throughout the mass of the fibers during their grafting. The object obtained, after demolding, is homogeneous, of great solidity. This object is immersed in a 20% calcium chloride solution until the solution is completely diffused throughout the object. It is checked that the diffusion was complete by calculation of the stoichiometry. Under the aforementioned conditions, the grafting rate was around 25% in MAEGP, which allowed fixation by calcium complexation of the order of 5%.

The object obtained can be used as a bone substitute. Calcium is, as in bone, linked to a phosphate function, which obeys the same laws as those prevailing in the body, to reserve or restore calcium as needed.

It is understood that the shape and structure of the object will be determined according to the destination of the bone substitute. It may in particular be provided with vascularization cavities and / or a central channel, so that said substitute is more similar, in terms of its use, to natural bone.

Other basic materials than polypropylene fibers can be envisaged. However, these must be chemically and biologically inert, and the object must have high mechanical strength. This resistance is obtained by an adequate orientation of the fibers preferably in the longitudinal direction, in the case of a long bone, or according to a distribution in the volume of the object which is a function of the constraints.
8 ° example. A 30g / m² silk fabric is impregnated using a 30% MAEGP solution and then activated under accelerated electrons at a dose of 20kGy (2MRad) under partial vacuum of 20 mm of mercury.

After drying, the fabric is weighed; the grafting rate is 36%. The harder feel imparted by grafting is corrected by impregnating a softener known under the name SAPAMINE OC, which is an amide derivative of a carboxylic acid of the cationic type, used as a finishing finish for wool and silk.

The fabric which has regained its flexibility is subjected to a fireproofing test according to standard ASTM D 1230.83. The burnt area is around 40cm³, which corresponds to classification B.

For comparison, the non-grafted tissue was subjected to the same test. The burnt area was around 150cm³, which corresponds to classification D.
9 ° example. Polypropylene fibers and kaolin powder are evenly distributed in a temporary mold compressible, then it is carried out as in Example 7 above, as regards grafting and immersion in a solution of calcium chloride. The object obtained, after polishing, has an appearance and consistency similar to that of ivory. It can also be sculpted and engraved in the mass.

The presence of the mineral filler improves the quality of the polishing and modifies the hardness of the material. Other fibers can be used, and the grafting technique will be adapted accordingly.

The invention is not limited to the embodiments and uses which have been described by way of nonlimiting examples, but covers all variants thereof. In particular during grafting, other monomers can be used with the phosphate monomer, carrying out a co-grafting.

Claims (17)

1. Grafted polymeric material characterized in that at least some of the grafts consist of a series of groups including phosphate groups of general formula :

   

   in which R₁ is selected from H and alkyl, R₂ is selected from alkylene and the oxides and/or polyoxides of alkylenes and R₃⁺ and R₄⁺ are either separate from each other, each being selected from H⁺, monovalent metal ions and cations bearing N⁺, or are one and the same, in which case R₃R₄²⁺ is a divalent metal ion.
2. Material according to claim 1, characterized in that R₁ is H and R₂ is (CH₂ - CH₂).
3. Use of the grafted polymeric material according to one of claims 1 or 2 as ion exchanger in a medium, the pH of which may vary from 0 to 12, in which R₃⁺ and R₄⁺ are H⁺.
4. Use of the grafted polymeric material according to one of claims 1 or 2 as material having antiseptic properties in a medium the pH of which may vary from 0 to 12, in which R₃⁺ and R₄⁺ or R₃R₄²⁺ are selected from the metal ions having recognized antiseptic properties, such as Ag⁺, Zn²⁺, Cu²⁺, Sn²⁺, Hg²⁺.
5. Use of the grafted polymeric material according to one of claims 1 or 2 as material having antiseptic properties in a medium the pH of which may vary from 0 to 12, in which R₃⁺ and R₄⁺ are selected from the cations comprising N⁺ and having recognized antiseptic properties such as benzalkonium, Malachite Green, derivatives of quinoline and chlorohexine.
6. Use of the grafted polymeric material according to one of claims 1 or 2, as substitute for bone in which R₃R₄²⁺ is Ca²⁺.
7. Use according to claim 6 of the grafted polymeric material in which the polymeric material is based on chemically and biologically oriented inert fibers and in which the extent of grafting is at least 20%.
8. Use according to claim 7 of the grafted polymeric material in which the polymeric material is polypropylene.
9. Use of the grafted polymeric material according to one of claims 1 or 2 as composite material without a binder in which the polymeric material is cellulose-based and the extent of grafting is at least 20%.
10. Use of the grafted polymeric material according to one claims 1 or 2, of which the extent of grafting is higher than 20%, as fireproof polymeric material.
11. Process for the manufacture of a grafted polymeric material according to claim 1, characterized in that it comprises a first step of grafting of the said material by an ethylenic ester of the phosphoric acid of general formula :

    

    in which R₁ is selected from the group constituted by H and the alkyls, and R₂ is selected from the group of the alkylenes and the oxides and/or polyoxides of alkylenes.
12. Process according to claim 11, characterized in that the cellulose-based polymeric material is impregnated with a solution of the ethylenic ester of the phosphoric acid, moulded then irradiated.
13. Process according to claim 11, characterized in that the polymeric material, being chemically and biologically inert, is, after grafting, immersed in a solution of calcium chloride.
14. Process according to claim 13, characterized in that the polymeric material consists of polypropylene fibers and in that the fibers are oriented in order to give, after binding of the calcium, a rigid article capable of being a substitute for bone.
15. Process for the manufacture of a grafted polymeric material usable as fireproof polymeric material according to claim 10, characterized in that the polymeric material being silk, it is impregnated, after grafting, with an amide derivative of a carboxylic acid acting as softener.
16. Process according to claim 11, for the manufacture of an article having the appearance of ivory, characterized in that the polymeric material is fibrous, in that after grafting, the material is immersed in a solution of an alkaline earth salt and that it is subjected to a finishing treatment such as polishing, carving or engraving.
17. Process according to claim 16, characterized in that, before grafting, a mineral filler, for example kaolin powder, is distributed homogeneously in the mass of the fibrous polymeric material.

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