BE1019837A3 - IMPROVED COMPOSITIONS WITH NETWORKED WATER-SOLUBLE POLYMERS. - Google Patents

Abstract

Drills or boron-containing substances for cross-linking water-soluble polymers such as polyvinyl alcohols, polyvinyl acetates, polysiloxanes or natural gums such as guar gum can be successfully replaced by one or more carbomers, which in turn are themselves preferably cross-linked. In this way, compositions are obtained which have intended pseudo-plastic properties and exhibit non-Newtonian flow behavior, without causing concern for possible health problems such as with the boron or boron-containing substances. The new improved compositions are useful, for example, as a paint, putty, a filler paste, or a gel, such as a toy gel. A kit of parts for the production of these compositions is also described.

Description

Improved compositions with cross-linked water-soluble polymers

SCOPE OF THE INVENTION

The present invention relates to water-based compositions containing cross-linked water-soluble polymers. More particularly, the invention relates to compositions useful as paint, putty, filler paste, gel, such as toy gel, in which polymers such as polyvinyl alcohols, polyvinyl acetates, polysiloxanes or polymeric Siloxanes, sometimes also called silicones, or suitable natural gums , preferably vegetable gums such as guar gum, are present in cross-linked form.

BACKGROUND OF THE INVENTION

Cross-linking of the aforementioned polymers is often achieved in the mentioned applications by adding a boron-containing substance.

For example, crosslinking of polyvinyl alcohols and / or guar gum in toy gels is often achieved by adding borax, or sodium tetraborate, and preferably in its decahydrate form Na2B4O7.10H2O. An example of this is "Slime® Gel from Mattel Toy Corp.". For the crosslinking of polyvinyl acetates in, for example, paint, use is generally made of added boric acid or its anhydride.

Likewise, pastes, padding, and even toys are known by names such as "Silly Putty", "Bouncing putty", or "Hüpfender Kitt" and the like, made on the basis of polysiloxanes, often polydimethylsiloxane (PDMS), and which have their non- Newtonian fluid properties derive from the crosslinking of a polysiloxane polymer such as, for example, silicone oil with the aid of a boron, often boric acid.

Casein, which can be extracted from milk by precipitation under the influence of enzyme or acid, can be converted into glutinous casein under the influence of borax. This casein can then be used to make a paint, often known as milk paint.

Now concerns have been raised recently about possible health problems that could be caused by boron, borax or another boron-containing substance.

The crosslinking of the polymers in these compositions is necessary to give the compositions the pseudo-plastic properties, or their non-Newtonian behavior, for which the products are ultimately so desired and / or needed.

However, humans can be exposed to the said compositions, such as paints. Children come in direct contact with the aforementioned toy gels. It is difficult to completely rule out the possibility that particles of these boron-containing compositions, and therefore also of borax or boron, can get into the human body, and what is even more sensitive, in the body of children.

Some of the products mentioned are often offered as a kit of parts, the boron and / or the boron-containing substance in one of the parts being offered in a solution or dispersion. This dispersion or solution represents an increased safety risk, and must be accompanied by warnings, hazard logos, and / or specific instructions regarding how to treat it and which actions should definitely be avoided under various laws. Despite taking these precautions, there is still a chance that the user does not recognize, record and / or follow these warnings, so that there is still a risk of any health problems that may be caused by the boron or boron.

A need has therefore recently arisen to avoid the boron, or the boron containing substances, in these applications. The crosslinking of the polymers in this composition must then be achieved in a different way.

The present invention therefore has for its object to replace the boron, and / or the boron-containing substances used in such compositions with a component which has the same cross-linking effect on these polymers, but is not accompanied by the same concerns with regard to a possible human exposure.

The present invention has for its object to provide for the avoidance or at least alleviation of the problems described above and / or general improvements.

SUMMARY OF THE INVENTION

According to the invention, there are provided new compositions, their production, and the use as defined in any of the appended claims.

Thus, the present invention provides a composition suitable for an application selected from the group consisting of a paint, a putty, a filling paste, a gel, such as a toy gel, which comprises a polymer selected from a polyvinyl alcohol, a polyvinyl acetate, a polysiloxane or polymeric siloxane, sometimes also called silicone, a suitable natural gum, and mixtures thereof, which polymer is crosslinked by means of a carbomer, which carbomer preferably consists of a homo- or copolymer of acrylic acid and / or methacrylic acid or a derivative of acrylic acid and / or methacrylic acid.

In another embodiment, the present invention provides for the use of a carbomer for cross-linking a polymer selected from a polyvinyl alcohol, a polyvinyl acetate, a polysiloxane or a polymeric siloxane, sometimes also called silicone, a suitable natural gum , and mixtures thereof, in a composition suitable for an application selected from the group consisting of a paint, a putty, a filling paste, a gel, such as a toy gel.

We have found that a carbomer, as defined in the context of this invention, can be a successful agent for cross-linking the water-soluble polymers as defined in the context of this invention. In this way, compositions containing these polymers can thus also acquire their pseudo-plastic properties, and behave as non-Newtonian substances. The family of carbomers, as defined in the context of this invention, have the advantage that they have been used for some time in drugs and cosmetics, without causing any concern. The carbomers are therefore based on a history of decades of safe use in applications where human exposure is expected to occur regularly, or is even intended. The use of carbomers in toxicologically more sensitive applications, such as those proposed in the context of the present invention, does not, therefore, lead to any concerns such as that with which boron or boron-containing substances have recently been associated.

In yet another embodiment, the invention provides a method for producing the composition of the present invention comprising a step of mixing an aqueous solution or dispersion of the carbomer in an aqueous solution of the polymer.

In yet another embodiment, the invention provides a kit of parts for the manufacture of a composition according to the present invention, which comprises on the one hand an aqueous solution of the water-soluble polymer and on the other hand an aqueous solution or dispersion of the carbomer includes.

This kit offers the advantage that the composition can be created by the user himself, just before its application. The components of the kit according to the present invention offer the advantage that they do not give rise to human exposure to any of them, that they also do not represent increased safety risks, and that they must be treated without warning plates and / or special safety phrases or warnings. offered to the user.

DETAILED DESCRIPTION

A wide range of polyvinyl alcohols can be used within the context of the present invention. Preferably the polyvinyl alcohols are at least partially hydrolysed, such as at least 50% molar, preferably at least 60%, more preferably at least 70%, even more preferably at least 80% or even 85% molar hydrolysed. Fully hydrolyzed polyvinyl alcohols are also useful for the present invention. Applicants preferably use a polyvinyl alcohol which at 15% by weight solids in water has a viscosity not higher than 20,000 centipoise (cP), preferably not higher than 10,000 cP, and even more preferably not more than 9,000 cP. A useful polyvinyl alcohol is, for example, Celvol ™ C325 available from Celanese, or POVAL available from Kuraray.

A wide range of polyvinyl acetates can be used within the context of the present invention. Preferably, the applicant uses polyvinyl acetates with a degree of polymerization of 50 to 100,000, more preferably of 70 to 50,000, even more preferably of 80 to 20,000, preferably of 90 to 10,000, and more preferably of 100 to 5,000.

A wide range of polysiloxanes or silicones can be used within the context of the present invention. Preferably, the applicant uses the hydroxy-terminated form. In addition, the inventor prefers at least partially linear polysiloxanes such as [SiO (CH3) 2] n (polydimethylsiloxane or abbreviated PDMS), including, for example, hexamethyltrisiloxane, octamethyltetrasiloxane, or decamethylpentasiloxane, or also aromatic siloxanes such as [SiO (C6H5) 2] polydiphenylsiloxane), but also cyclic siloxanes, such as cyclotri, cyclotetra, cyclopenta, or cyclohexasiloxanes, such as, for example, tetramethylcyclotrisiloxane, hexamethylcyclotetrasiloxane, octamethylcyclopentasiloxane, or decamethylcyclohexasiloxane.

Various natural gums may be used as natural gums within the context of the present invention, primarily guar gum, but also xanthan gum or substances known in English under names such as xanthan gum, arabic gum, dextran, welan gum, gellan eraser, diutan eraser and pullulan.

In one embodiment, the composition of the present invention comprises the water-soluble polymer in a concentration of 0.1% to 40% weight, preferably at least 0.5% weight, more preferably at least 1.0% weight, even more preferably 1.5% weight, at preferably at least 2.0% weight, more preferably at least 2.5% weight and even more preferably at least 3.0% weight, and this on the basis of the total weight of the composition. In addition, the composition preferably contains the water-soluble polymer in a concentration of at most 30% by weight, more preferably at most 20% by weight, even more preferably at most 10% by weight, preferably at most 7.0% by weight, more preferably at most at most 6.0% by weight, even more preferably at most 5.0% by weight, and most preferably at most 4.0% by weight, also based on the total weight of the composition.

For the purposes of this invention, a carbomer or carbomer is defined as a water-soluble polymer comprising as monomer an unsaturated acid, or a derivative thereof, such as an ester or amide, which can preferably be represented by the formula CH2 = CR- CO-G or CH2 = CR-COO-A1. In this formula, R represents a substituent selected from the group of H, monovalent alkyl, aryl or alkylaryl radicals and monovalent cycloalkyl radicals, although H is the preferred substituent, with CH3 a very acceptable second choice. However, R can also be selected from the group of alkyl, alkoxy, haloalkyl, cyanoalkyl and similar groups with 1 to 9 carbon atoms. G can represent an amine group NL 2, such as -NH 2, in which case the monomer is preferably acrylamide or methacrylamide. A 1 and / or L may independently represent a substituent selected from the group consisting of H, monovalent alkyl, aryl or alkylaryl radicals and monovalent cycloalkyl radicals, although H as a substituent is preferred, in which case the monomer is a unsaturated carboxylic acid. Nevertheless, A1 and / or L can also be selected from the group of alkyl, alkoxy, haloalkyl, cyanoalkyl and similar groups containing 1 to 35 carbon atoms.

The carbomer is preferably predominantly or wholly a homopolymer of (meth) acrylic acid or methacrylic acid, or a copolymer of mixtures thereof, and which may be cross-linked.

Other copolymers may optionally be used. In addition to a monocarboxylic acid and / or its ester, use can also be made of a polycarboxylic acid and / or its ester as a comonomer, such as an acrylate or methacrylate, and optionally an alkyl alkoxylated ester, such as an alkyl alkoxylated acrylate or methacrylate. In particular, olefinically unsaturated carboxylic acids with at least one carbon-carbon-olefinic double bond, and at least one carboxyl group, and / or esters thereof are preferred. Suitable examples include acrylic acids, in particular acrylic acid, methacrylic acid, ethacrylic acid, alpha-cyano acrylic acid, beta-methylacrylic acid (crotonic acid), alpha-phenyl acrylic acid, beta-acryloxy propionic acid, cinnamic acid, p-chloro cinnamic acid, 1-carboxy-4 -phenyl butadiene-1,3,3-acrylamido-3-methylbutanoic acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid and tricarboxy ethylene. Examples of suitable polycarboxylic acids include the acid anhydrides, such as maleic anhydride, the anhydride group being formed by the elimination of a water molecule from two carboxyl groups on the same carboxylic acid molecule. However, acrylic and methacrylic acid are preferred.

The alkyl alkoxylated acrylate or methacrylate is a hydrophobic comonomer. The hydrophobic comonomer will usually be an ester of an acid or a mixture of two or more thereof, and may also include one of the various known (meth) acrylates or (meth) acrylamide.

The alkyl group of the alkoxylated alkyl (meth) acrylate can contain 5-30 carbon atoms, preferably 15-30, more preferably 20-25 carbon atoms. The alkyl structure can contain primary, secondary or tertiary carbon configurations. Examples of suitable alkyl alkoxylated acrylates include methoxymethyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, butoxy acrylate or ethoxypropyl acrylate. The alkyl structure may also contain a phenyl group, which may be substituted, and suitable alkyl structures are octylphenyl crotonates, nonylphenyl and dodecylphenyl structures, the alkoxylated derivatives of which are readily available commercially with ethoxy and / or propoxy groups.

The monomers in the carbomer can be octadecyl acrylate, behenyl acrylate, dodecyl acrylate, hexadecyl acrylate and the like, and cyano derivatives thereof; methacrylates such as steryl methacrylate, methyl methacrylate, ethyl methacrylate, octyl methacrylate, isopropyl methacrylate, 2-ethylhexy; methacrylate, n-hexyl methacrylate, octadecyl methacrylate, behenyl methacrylate, dodecyl methacrylate, hexadecyl methacrylate, and the like. Mixtures of two or three or more long chain acrylic esters can be successfully polymerized together with one of the carboxylic acid and / or ester monomers. Preferred hydrophobic monomers are the linear, long chain hydrophobic monomers in which the alkyl group contains at least 12 carbon atoms, such as stearyl methacrylate, hexadecyl methacrylate and behenyl methacrylate. Optionally, a complex hydrophobic can be used with polyalkylene oxide branches capped with hydrophobic alkyl or alkylaryl groups.

For a (meth) acrylic acid ester of an alkoxylated alcohol, the alkyl group is typically selected from a C8 -C24 alkyl group, an alkylaryl group, including alkylphenyl groups such as octylphenyl crotonates and nonylphenyl, or the residue of a polycyclic hydrocarbon compound such as lanolin or cholesterol . Suitable alkyl groups include tridecyl, myristyl, pentadecyl, cetyl, palmityl, stearyl, eicosyl and behenyl or docosyl or mixtures thereof. Such a suitable monomer mixture can originate, for example, from the alkoxylation of a mixture of lauryl, stearyl, cetyl, and palmityl alcohols.

The carbomer (co) polymer described above is preferably cross-linked. Various polyunsaturated monomers can be used as crosslinking agent, whereby either a partially or substantially cross-linked three-dimensional network is obtained. Suitable crosslinking agents include sucrose or sucrose or pentaerythritol allyl ethers, or other polyunsaturated monomers, e.g. divinyl glycol, polyallyl phosphate esters, diallyloxy compounds, phosphite esters, and the like. Typical polyunsaturated monomers include di, tri or tetra, penta, or hexa-allyl or sucrose or sucrose, di, tri or tetra-allyl pentaerythritol; diallyl phthalate, diallyl itaconate, diallyl fumarate, diallyl maleate, divinylbenzene, allyl methacrylate, allyl citrate, ethylene glycol di (meth) acrylate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, tacrylate, tacetrylene, tacetylene, ethylene dimethacrylate, triethylene glycol methacrylate, methylene bisacrylamide, and the like. Castor oil or polyols, esterified with ethylenically unsaturated carboxylic acid and the like can also be used. Preferred crosslinking agents include allyl pentaerythritol, allyl sucrose or sucrose, trimethylolpropane allyl ether and divinyl glycol.

A preferred carbomer of the present invention can be a polymer of the formula (I)

In another embodiment, the carbomer of this invention is a polymer of the formula (II).

In the formulas (I) and (II), z can be either 0 or 1, and if z is 1, (x + y): z can be from 4: 1 to 1,000: 1, preferably from 6: 1 to 250 : 1; wherein the monomer units can be in any order, with y preferably from 0 to a maximum, equal to the value of x; n is at least 1; and furthermore R further has the meaning as stated herein before; R 1 represents from 1 to 50 independently selected alkyleneoxy groups, preferably ethylene oxide or propylene oxide groups; R2 represents a C4 -C35 hydrocarbon group, preferably saturated alkyl but possibly with a phenyl group, in which case we prefer to see R2 an octyl phenol, a nonyl phenyl or a dodecyl phenyl group; R 3 represents a hydrogen or a C 1 -C 4 alkyl, preferably H or CH 3; A1, A2 and A3 are independently selected from hydrogen and alkyl groups, preferably C1 -C4 alkyl groups.

In the formulas (I) and (II), each of the groups -O-A1, -O-A2 or -O-A3 can also be replaced by an amine group, typically with the formula -NL2, where L has the meaning as indicated above.

Any suitable polymerization technique can be used to produce the carbomer. We prefer to use a free radical polymerization technique as known in the art, for example as described in Kirk-Othmer, 5th edition, Wiley, in volume 20.

In an embodiment of the present invention, the carbomer has an average molecular weight Mn in the range of 20,000 to 5,000,000, preferably 35,000 to 3,000,000, more preferably 50,000 to 2,000,000, even more preferably 70,000 to 1,000 .000, even more preferably 80,000 to 500,000, even more preferably 90,000 to 200,000 and most preferably at most 130,000 as measured by GPC. The carbomer is preferably cross-linked. The molecular weight is preferably determined by gel permeation chromatography (GPC) with the carbomer dissolved in dimethylacetamide (DMA) and with an analytical system calibrated with polymethyl methacrylate reference standards. More preferably, the carbomer analyzed in this way also, always with respect to DMA, has a molecular weight in the range of 50,000 to 5,000. 000, preferably 100,000 to 3,000,000, more preferably 130,000 to 2,000. 000, and even more preferably 150,000 to 200,000. The polydispersity of the copolymer is preferably in the range of 1-5, more preferably 1.1 to 4.0, even more preferably 1.2 to 3.0, even more preferably 1.3 to 2.0 , even more preferably 1.4 to 1.7 and even more preferably at most 1.7, determined according to the same method.

The effects described above are particularly pronounced with a carbomer additive containing an acrylic acid homopolymer, in particular an α, β unsaturated monoacid acrylic acid with 3-5 carbon atoms, corresponding to formula III:

formula III

wherein R represents a substituent selected from the group consisting of H, monovalent alkyl, aryl or alkylaryl radicals and monovalent cycloalkyl radicals, although H is a substituent. However, R can also be selected from the group of alkyl, preferably methyl, alkoxy, haloalkyl, cyanoalkyl and similar groups with 1 to 9 carbon atoms.

Homopolymers of acrylic acid and methacrylic acid are preferred because they are readily available commercially at an economically viable cost and because they exhibit the desired reduction in viscosity when exposed to pressure in the gluing operation.

A preferred viscosity ratio between a first situation in which no pressure and no shear forces are applied to the composition and a second situation in which the surface gluing composition is subjected to pressure and shear forces is obtained with an additive in which the homopolymers are crosslinked with a crosslinking agent, which is a polyfunctional monomer with at least two terminal vinyl CH 2 = C groups, and with a molecular weight as previously indicated, or also between 0.05-100, preferably between 0.5 and 10, more preferably between 1 -5x10 exp 9 Dalton, the additive with the property that when using shear forces, the viscosity decreases, and the viscosity increases immediately as the shear forces are removed.

Use is preferably made of a cross-linking agent which is a polyalkenyl polyether, in particular an allyl pentaerythritol. Other suitable crosslinking agents are polyfunctional monomers with at least two terminal CH 2 = C or vinyl groups, such as, for example, in butadiene, isoprene, divinyl benzene, divinyl naphthalene, allyl acrylates, and the like. Preferred cross-linking agents are those containing an alkenyl group in which an olefinic double bond is attached to a terminal methylene group. Particularly preferred crosslinking agents are polyethers with on average two or more alkenyl ether groups per molecule. Other suitable crosslinking monomers include diallyl esters, dimethylallyl ethers, allyl or methallyl acrylates, acrylamides. Examples thereof are allyl pentaerythritol, allyl sucrose or sucrose, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, trimethylolpropane propane diallyl ether, pentaerythritol triacrylate and the like.

The effects described above have also been observed with an additive comprising a copolymer, wherein the acrylic acid of the formula III is copolymerized with at least one alkyl acrylate of the formula IV:

formula IV

wherein R 'is selected from the group consisting of H, methyl, ethyl and R "is a C 10 -C 30 alkyl group, preferably a C 10 -C 20 alkyl group, the copolymers are preferably cross-linked with a cross-linking agent which is a polyfunctional monomer with at least two terminal vinyl CH 2 = C groups as described above.

Representative acrylates of formula IV are methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, methyl ethyl acrylate, octyl acrylate, lauryl acrylate, stearyl acrylate, behenyl acrylate, and the corresponding methacrylates. Suitable copolymers include copolymers of a mixture of two or more of the above compounds with the acrylic acid of formula III. Other comonomers include acrylic nitriles, olefinically unsaturated nitriles, preferably those with 3-10 carbon atoms, for example acrylonitrile and methacrylonitrile; mono-olefinically unsaturated acrylic amides, for example acrylamide and methacrylamide, N-alkylolamides of α, β-olefinically unsaturated carboxylic acids including those with 4-10 carbon atoms, preferably N-methylol methacrylamide.

Suitable commercially available products for use as the carbomer in the context of the present invention are available from Sigma Chemical Company, such as the products offered under the trade name Polygel®, e.g. Polygel® CB 3V, Rohm & Haas, e.g. the products offered under the trade name Acusol®, Noveon or Lubrizol, for example products offered under the trade names Pemulen ™ and / or Carbopol®, such as Carbopol 674 or 981, Carbopol ETD 2050, or Novethix® L-10, from Wako Pure Chemical Industries in Japan, or from Allied Colloids from Great

UK, for example Salcare ®, or the products offered under the trade name Flosperse ™ by SNF Floerger. The carbomer can be obtained as a solid powder, such as the Carbopol 674 or the Polygel CB-3V, but they can also be obtained as liquid dispersions, such as Polygel W400 or W301 Polygel or Polygel DR. The liquid forms are easier to process because they do not require mixing under high shear forces, which is highly desirable for solubilizing a powder carbomer. Novethix L-10 is described in great detail in our pending patent application PCT / EP2010 / 053051.

In an embodiment of the present invention, the carbomer comprises a homopolymer of an α, β-unsaturated monoacid acrylic acid with 3-5 carbon atoms, corresponding to formula III:

formula III

wherein R is a substituent selected from the group of H, monovalent alkyl, aryl, alkylaryl radicals, monovalent cycloalkyl radicals, alkoxy, haloalkyl, cyanoalkyl of 1 to 9 carbon atoms, the homopolymers preferably crosslinked with a crosslinking agent which is preferably a crosslinking agent is a monomer with at least two terminal vinyl CH 2 = C groups.

In another embodiment of the composition according to the present invention, the carbomer comprises a copolymer of (i) an α, β-unsaturated monoacid acrylic acid corresponding to formula III with 3-5 carbon atoms:

formula III

wherein R is a substituent selected from the group of H, monovalent alkyl, aryl, alkylaryl radicals, monovalent cycloalkyl radicals, alkoxy, haloalkyl, cyanoalkyl of 1 to 9 carbon atoms, with

(ii) at least one alkyl acrylate represented by formula IV

formula IV

wherein R 'is selected from the group consisting of H, methyl, ethyl and wherein R "is a C 10 -C 30 alkyl group, the copolymers are preferably cross-linked with a cross-linking agent that is preferably a polyfunctional monomer with at least two terminal vinyl CH 2 = C groups.

In this embodiment, in the formula IV, R "is preferably a C 10 -C 20 alkyl group.

In another embodiment of the present invention, the carbomer has an average molecular weight Mn in the range of 20,000 to 5,000,000, as measured by Gel Permeation Chromatography (GPC).

Preferably the carbomer of the present invention is itself cross-linked and preferably the cross-linking agent of the carbomer is a polyalkenyl polyether.

In a further embodiment, the cross-linking agent of the carbomer is an allyl pentaerythritol.

In a further embodiment, the carbomer in the composition according to the present invention itself is a pseudo plastic material.

In another embodiment, the composition of the present invention comprises the carbomer in a concentration of 0.01% to 20% by weight, preferably at least 0.05% by weight, more preferably at least 0.10% by weight, even more preferably 0.20% by weight, at preferably at least 0.30% weight, more preferably at least 0.40% weight and even more preferably at least 0.50% weight, and this on the basis of the total weight of the composition. In addition, the composition preferably contains the carbomer in a concentration of at most 15% by weight, more preferably at most 10% by weight, even more preferably at most 5% by weight, preferably at most 4.0% by weight, more preferably at most at most 3.0% weight, more preferably at most 2.0% weight, and most preferably at most 1.0% weight, also based on the total weight of the composition.

When dosing the carbomer in the composition of the present invention, preferably enough carbomer is added to clearly mark the properties of dilatant liquid, or of non-Newtonian substance. Preferably, sufficient carbomer is added to the polymer to largely prevent tackiness. Also, the composition of the present invention has sufficient polymer and carbomer together to have a higher viscosity than that of typical smearable glue, such as at least 1,000 cP in a Brookfield RV viscometer with spindle 4 and at a spindle rotation speed of 150 rotations per minute ( rpm). The applicants also prefer that the composition according to the present invention exhibits a viscosity of at least 10,000 cP in the same test at 10 rpm. At 5 rpm spindle speed, the inventors prefer a viscosity of at least 15,000 cP in this test.

In one embodiment, the composition of the present invention is suitable as a gel, for example as a toy gel, and comprises a polymer selected from polyvinyl alcohol, a polysiloxane, and a suitable natural gum, and mixtures thereof. The inventors have found that the carbomer is a very suitable crosslinking agent for polyvinyl alcohol, as well as for the polysiloxane, and for natural gums, such as guar gum, and also of mixtures thereof. In this way, these water-soluble polymers can be cross-linked in a toxicologically unexpected manner, the compositions they contain can be given pseudo-plastic properties and a non-Newtonian flow behavior, and can be used in sensitive applications where human exposure cannot be excluded, without being associated with possible unwanted health problems.

In another embodiment, the composition according to the present invention is suitable as a paint, a putty, a filling paste, which contains a polyvinyl acetate. Here too the same advantages can be cited as described above for the toy gel. In these applications, the composition preferably also comprises an element selected from a filler and a colorant, and mixtures thereof. The composition preferably exhibits sufficient adhesion to fulfill its stated function, but not sufficient adhesiveness or tack to still serve as an adhesive. The viscosity is also generally too high to be spreadable well as glue, but still to be able to be spread out as paint.

The composition according to the present invention may also contain an element selected from the list consisting of a dye, a filler, a pigment and a UV stabilizer, and mixtures thereof.

In one embodiment, the composition of the present invention contains less than 0.05% by weight of boronous substances, preferably less than 0.01% weight, more preferably less than 50 ppm weight, even more preferably less than 20 ppm weight, and at preferably less than the detection limit of the boronous substances, always relative to the total weight of the composition.

In another embodiment of the composition according to the present invention, the boronous substances, the concentration of which is preferably kept as low as possible, are selected from boric acid, a sodium or potassium polyborate, in its hydrated or unhydrated form, boric anhydride, sodium or potassium metaborate, preferably a sodium tetraborate, pentaborate or octaborate, more preferably sodium tetraborate decahydrate (borax), and mixtures thereof.

In a further embodiment, the composition of the present invention contains less than 0.05% weight of boron, in free or in bonded form, preferably less than 0.01% weight, more preferably less than 50 ppm weight, even more preferably less than 20 ppm weight, and preferably less than the detection limit of boron as can be determined with Atomic Absorption Spectrometry (AAS), always relative to the total weight of the composition.

It is mainly this low presence of boron or boron-containing substances, or preferably the absence thereof, that can offer the benefit of a reduced level of concern for health problems when using the compositions of the present invention.

Now that this invention has been fully described, those skilled in the art will realize that the invention can be implemented with a wide range of parameters within what is claimed, without therefore departing from the spirit and scope of the invention. As understood by those skilled in the art, the general invention, as defined by the claims, includes other preferred embodiments that are not specifically mentioned.

Claims (19)

The use of a carbomer for cross-linking a water-soluble polymer selected from a polyvinyl alcohol, a polyvinyl acetate, a polysiloxane, or a polysaccharide gum, and mixtures thereof, in a composition suitable for an application selected from the group consisting of from a paint, a putty, a filling paste, and a gel, such as a toy gel. A composition suitable for an application selected from the group consisting of a paint, a putty, a filling paste, and a gel, such as a toy gel, which comprises a water-soluble polymer selected from a polyvinyl alcohol, a polyvinyl acetate, a polysiloxane, or a polysaccharide gum, and mixtures thereof, which polymer is crosslinked by means of a carbomer, which carbomer preferably consists of a homo copolymer of acrylic acid and / or methacrylic acid or a derivative of acrylic acid and / or methacrylic acid. The composition according to claim 2, characterized in that the carbomer comprises a homopolymer of an α, β-unsaturated monoacid acrylic acid with 3-5 carbon atoms, corresponding to formula III:

formula III wherein R is a substituent selected from the group of H, monovalent alkyl, aryl, alkylaryl radicals, monovalent cycloalkyl radicals, alkoxy, haloalkyl, cyanoalkyl with 1 to 9 carbon atoms, the homopolymers preferably crosslinked with a crosslinking agent which is preferably is a monomer with at least two terminal vinyl CH 2 = C groups. The composition according to claim 2, characterized in that the carbomer comprises a copolymer of (i) an α, β-unsaturated monoacid acrylic acid corresponding to formula III with 3-5 carbon atoms:

formula III wherein R is a substituent selected from the group of H, monovalent alkyl, aryl, alkylaryl radicals, monovalent cycloalkyl radicals, alkoxy, haloalkyl, cyanoalkyl of 1 to 9 carbon atoms, with (ii) at least one alkyl acrylate represented by formula IV

formula IV wherein R 'is selected from the group consisting of H, methyl, ethyl and where R' is a C10 -C30 alkyl group, the copolymers are preferably crosslinked with a crosslinking agent which is preferably a polyfunctional monomer with at least two terminal vinyl CH2 = C groups. The composition according to claim 4, characterized in that in the formula IV, R "is a C 10 -C 20 alkyl group. The composition of any one of claims 2-5, wherein the carbomer has an average molecular weight Mn in the range of 20,000 to 5,000,000, as measured by Gel Permeation Chromatography (GPC). The composition according to any one of claims 2-6, characterized in that the carbomer itself is cross-linked and preferably the cross-linking agent of the carbomer is a polyalkenyl polyether. The composition according to claim 7, characterized in that the cross-linking agent of the carbomer is an allyl pentaerythritol. The composition according to any of claims 2-8, characterized in that the carbomer is a pseudo plastic material. The composition of any one of claims 2-9 containing the carbomer in a concentration of 0.01% to 30% by weight, based on the total weight of the composition. The composition of any one of claims 2-10 suitable as a toy gel, comprising a polymer selected from polyvinyl alcohol, a polysiloxane and a suitable natural gum, and mixtures thereof. The composition of any one of claims 2-10 suitable as a paint, putty, or filler paste, comprising a polymer selected from polyvinyl acetate, a polysiloxane, and mixtures thereof. The composition of any one of claims 2-12 containing less than 0.05% by weight of boronous substances, preferably less than 0.01% weight, more preferably less than 50 ppm weight, even more preferably less than 20 ppm weight, and preferably less than the detection limit of the boronous substances, always relative to the total weight of the composition. The composition of claim 13 wherein the boronous substances are selected from boric acid, a sodium or potassium polyborate, in its hydrated or unhydrated form, boric anhydride, sodium or potassium metaborate, preferably a sodium tetraborate, pentaborate or octaborate, more preferably sodium tetraborate decahydrate (borax), and mixtures thereof. The composition of any one of claims 2-14 containing less than 0.05% weight of boron, in free or in bonded form, preferably less than 0.01% weight, more preferably less than 50 ppm weight, even more preferably less than 20 ppm by weight, and preferably less than the detection limit of boron as can be determined with Atomic Absorption Spectrometry (AAS), always relative to the total weight of the composition. A method for producing the composition of any one of claims 2-15 comprising the step of mixing an aqueous solution or dispersion of the carbomer in an aqueous solution of the polymer. The method of claim 16 wherein the carbomer, under conditions where the carbomer is subjected to high shear mixing conditions, is mixed in an amount of water to form the aqueous solution or dispersion of the carbomer. The method according to claim 16 or 17, wherein additional ingredients are mixed in, preferably before the carbomer and the polymer are combined. A kit of parts for the manufacture of a composition according to any of claims 2-15, which on the one hand contains an aqueous solution of the water-soluble polymer and on the other hand contains an aqueous solution of the carbomer.