LU86880A1 - GLASS MICROBALLS INTENDED TO BE IN CONTACT WITH POLYMERIZABLE MATERIALS; PROCESS FOR TREATING GLASS MICROBALLS TO MAKE THEM SUITABLE FOR USE AND POLYMERIZATION METHOD USING SUCH MICROBILLES - Google Patents

Description

! , BL-4036 / BK

i i ~ "ΤΓί Λ GRAND-Dl CHÉ DE LUXEMBOURG

. j Patent N “K. - -,.

SfMister Minister of ^ May ............... j JfSgjfL of Economy and Classes Mot ennes

qwlM Intellectual Property Service _ ~ _I * LUXEMBOURG

yflj Λ / ί £ 8 '. 'Application for Invention Patent CL · Ac.4 ^ l_ Ί -------------------—-------------- ( "I. Request

The soc, known as GLAVERBEL S. & .. Chaussée de la Hulpe 166. 1170 Bruxelles, (2) Belgique ____________________..._______________________________________________________________________________ „_________ represented by E.Meuers & ETFreglinqer, Ing.conseils en pi, _ (3) 46 rue du Cimetière, Luxembourg, ______ acting as mandataries____ files! nti this ___________ fourteen.may nineteen hundred eighty seven _____________ (4) - ôô at 15 ................... hours , to the Ministry of the Economy and the Middle Classes, in Luxembourg: 1. this request for obtaining a patent of invention concerning:

Glass microbeads intended to be brought into contact with materials (^ polgmérisables; pjxicédè de "traitianant Hë microbillès ^ é glass pour les lcmïïfë'âptës ^ ~ mi ~ teI'lisage ~ ëTprôcêdë ^ e ~ pôlgmêrisâi: ïôn ~ Îâlsan ~ appel. to "such microbilities .----------------------------------------- ---------------------------------------- 2. the description in French _______________________________________ of the invention in three copies; 3. .....................................- drawing boards, in three copies; 4. the receipt of the fees paid to the Luxembourg Registration Office, .. May 14, 1987____; 5. the delegation of power, dated „.Brussels ............. ............. on ... 12. mal 1987_____; 6. the successor document (authorization); declares (s) assuming responsibility for this declaration, that the ( es) inventor (s) is (are): (6)

Pierre LAROCHE, ....... rue ..... du Calvaire 60, B ..... 6290 Naliimes (Belgium) ___ \ _______ ___1 claims (s) for the above patent application the priority of a (of) request (s) from (7) ....................................... ...- s = _____________________________________________________________ filed in (8) _______________________________ on (9) ............................... ..... — .............................._------------- ---------------------------------------------- under the N ° (10) ..............._________________________________________________________________________________________ on behalf of (11) ......................... ______________________________________________________________________________________________________________________________________________________________ elects (elect) domicile for him / her and, if designated, for his / her representative, in Luxembourg______ 46 rue du Cimetière, ..Luxembourg ______________________________________________________________________________ _________ (12) requests (s) the grant of a patent for the subject described and represented in the abovementioned appendices, with postponement of this grant to ____________ eighteen _______________________________________________________________ months. (13)

Applicant: E *. Meners ............................................ .................._............................... ....— ----------- (14) τ Π. Deposit Minutes

The aforementioned patent application has been filed with the Ministry of the Economy and the Middle Classes, Intellectual Property Service, Ajmxembourg, dated: May 14, 1987 / i '-' W \ Pr. The Minister of Economy and of the Middle Classes,

. 7 coo / i / fi-; -i '\ * \ a L

15 hours / * ; * t / ard.

I ί; i * I yfj / i o '. γ'ΐ ',. Ψ- j ~ I The head of the intellectual property department, \%. ... v * / A / A 68007_VV.; - '... y? / _ X) / _- EXPLANATIONS RELATING TO ^ DfîÂral FORMUlXs · ^' {3 \ if there is "Request for certificate of addition a »HirtiVfrpHtffipal, in main patent application No ............ of ........... (2) enter the surname, first name, profession.

address * of the applicant. when the latter is an individual or the corporate name, legal form, address of the head office. when the applicant is a legal person - (3) register Hôlio QL34RETY4050

DESCRIPTIVE MEMORY

attached to a request for

PATENT

filed by the so-called Company

GLAVERBEL

166, Chaussée de la Hulpe B.1170 - Brussels (Watermael-Bcitsfort)

Belgium for: "Glass microbeads intended to be brought into contact with polymerizable materials; process for treating glass microbeads to make them suitable for such use and polymerization process using such microbeads."

Inventor: Pierre LAROCHE

1.

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The present invention relates to glass microbeads intended to be brought into contact with polymerizable materials, a process for treating glass microbeads to make them suitable for such use, a polymerization process using such microbeads in particular, a road marking process and a process for shaping parts made of polymer material.

Numerous polymerizable materials are known, and their use in increasingly varied fields is widely spread. Considerable interest in this type of material lies in the fact that they can be used in a fluid, liquid or even visco-elastic state to shape them by molding, extrusion, injection techniques, etc. at controlled temperature. Many thermoformable resins at room temperature or moderate or cold formable by this type of technique require the presence of a catalyst to initiate the chain reaction which forms polymer macromolecules. It is obvious that the success of the polymerization operation, that is to say the obtaining of a homogeneous polymer mass requires contacting, and therefore a homogeneous distribution of the catalyst in the polymerizable material.

On the other hand, to modify the mechanical, thermal or electrical properties of a polymer, or even quite simply to reduce the cost of parts formed from polymers, it is common to mix the material which polymerizes with a "filler" . Such a filler has often been made up of glass fibers when it is desired to obtain a plastic material having high mechanical strength. Currently, fillers made up of microbeads are used more and more. Glass microbeads are particularly advantageous because their perfect sphericity allows a uniform distribution of tensions in the polymer. The use of hollow glass microbeads or microbubbles is also advantageous since it makes it possible to manufacture low density plastic parts.

In the field of paintings, among others 2.

‘. I

t i paints intended for road marking, it is also more and more common to use materials which polymerize. To make such paints reflective, glass microbeads are introduced. A known technique, illustrated for example by patent ÜS 2,897,732, consists in spreading, on a road, separately, a polymerizable paint of the fluid polyester-vinylidene copolymer type and a polymerization catalyst (peroxide) and then sprinkling the painting with glass beads before complete polymerization of the paint. This technique requires the use of a complicated apparatus: a paint spray gun, a device for spreading the catalyst or for bringing it to the spray gun by a pipe separate from the paint supply and a device for spread the microbeads. The results obtained with such a known technique are unsatisfactory: the fine powder catalyst partially flies off during spraying, the catalyst deposits essentially on the surface of the paint layer, which causes differential polymerization of the layer and superficial cracks, a lack of catalyst at the heart of the paint.

There is therefore a demand for a regular and homogeneous supply of catalyst in polymerizable materials. Unexpectedly, we have found that it is possible to ensure this homogeneous supply by associating the introduction of catalyst with that of the microbeads in said material. This simplifies the shaping and / or curing operations of the polymer.

According to the present invention, glass microbeads are characterized in that their surface carries a coating comprising a polymerization catalyst. The association of the catalyst with the microbeads serving as a filler in the polymer is unexpected: indeed, there is every reason to believe that if the catalyst is attached to a material foreign to the polymerizable material, its reactivity with respect to this this will be inhibited. Unexpectedly, 3.

î «Γ * · we have observed that this is not the case but that, on the contrary / the microbeads entrain the catalyst which is attached to it within the material to be polymerized where it acts efficiently and is distributed uniformly . It has even been observed that in certain cases it is possible to use, by this technique, less catalyst than in the absence of the microbeads. The spherical shape of the beads also helps to distribute the catalyst evenly.

Advantageously, said catalyst is adsorbed in a layer of coating material adhering to said surface. This makes it possible to fix the catalyst to the microbeads permanently in such a way that these microbeads can be stored, stored and handled without pei'te of the catalyst and without reducing the reactivity of the catalyst vis-à-vis the material to be polymerized (resin, paint , ...).

It has been found that a series of compounds capable of chemically adhering to the glass firmly can be chosen to fix said catalyst. Among other things, the organometallic compounds chosen from silanes, chromium complexes, titanium derivatives or polymers containing a methoxysilyl group are particularly suitable. In fact, these compounds bind chemically to glass and, on the other hand, promote coupling between glass and the main usual polymeric materials such as resins of the polyester family, polyacrylates.

By way of example, mention may be made of vinylsilanes (A151 from Union Carbide), methacryloxysilanes (A174 from Union Carbide), styrylsilanes, chromium complexes of the Werner type, among others the complexes with fumaric acid (Volans from du Pont), isopropyl titanates (TSM2-7, TSA2-11, TTI433, TTAC-39 from Kenrich) and special polymers with methoxysilyl groups (Polyvest 25 from Hüls).

Preferably, the surface of the glass microbeads 35 according to the invention, which carries said coating, is rough. It has been noted that increasing the specific surface of the microbeads makes it possible to increase the quantity of catalyst 4.

'. ï ". l · carried by the balls and the introduction of such balls into the material to be polymerized makes it possible to obtain hardening in very short periods or at a lower temperature. Such beads are particularly preferred when curing is required in a very short time, for example for curing a layer of paint. It goes without saying that the beads with a rough surface at least partially lose the reflective properties for which they are generally used in road marking paints, but this does not however have any drawback since it suffices to use these rough microbeads carrying the catalyst in mixture with other microbeads which provide retroreflection.

This is why an advantageous form of the invention consists of a mixture of microbeads as described above and glass microbeads coated with a coating which makes them hydrophobic and oleophobic. Such a mixture is particularly well suited to use for road marking because the microbeads carrying the catalyst can be sprinkled on the liquid paint at the same time as the hydrophobic, oleophobic beads: a very simple apparatus is thus used comprising a gun delivering the polymerizable material and a single ball-catalyst projection head. The balls carrying the catalyst will mix in the heart of the paint layer while the hydrophobic, oleophobic balls float on the paint layer where they reflect the incident light.

In such a mixture, it is advantageous to add at least 70% by weight of microbeads carrying a catalyst, in accordance with the present invention, which makes it possible to quickly form layers of polymerized retro-reflective-chissant paint.

The presence of rough microbeads carrying a catalyst is particularly recommended in resins which polymerize in the presence of a filler which acts as a white pigment (chalk, titanium oxide, etc.). Indeed, ; f c i 5.

in this particular case, the opaque white appearance of the balls allows them to replace a charge which is generally much more expensive while providing the polymerization catalyst.

There are various polymerization catalysts.

Among these, peroxides play a predominant role in the polymerization of unsaturated polyester resins. They allow curing at room or moderate temperature, possibly in the presence of an accelerator. Benzoyl peroxide is particularly used and exists in the form of a powder which is easy to handle. This is why an advantageous form of the invention comprises glass microbeads carrying a coating comprising a peroxide.

The present invention relates to solid glass microbeads as well as hollow glass microbeads or microbubbles. As already mentioned above, the two classes of balls have a wide range of uses specific to each of them. The microbeads used as a filler in molded plastics preferably have an average diameter of the order of 44 μ. The microbeads used in paints generally have an average diameter between 50μ and 650μ. As is preferred, the microbeads according to the invention carrying a coating comprising a polymerization catalyst have an average diameter between 50 and 650 μ. It is obvious that the smaller the specific surface area of the beads, the lower will be the amount of catalyst provided by them. In the case of the casting or molding of resins, it is therefore sufficient to choose the size of the beads as a function of the quantity of catalyst required. In the case of paints or resins for which the contact with balls is made by projection of the balls on a thin layer of material to be polymerized, it may be advantageous to use balls of relatively large diameter (150-650μ) which will entrain the catalyst within the layer, even if the amount of catalyst present on such beads is relatively small.

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The present invention also relates to a method for obtaining the glass microbeads which have just been described. According to a second aspect of the invention, a method of treating glass microbeads during which a coating is deposited on the microbeads is characterized in that a coating of an organometallic compound is formed on the surface of the beads. a polymerization catalyst is attached to this coating.

Such a process is simple to carry out and makes it possible to manufacture microbeads capable of mixing with various polymerizable materials in fluid or viscoelastic form, thus drastically simplifying the shaping of polymeric materials loaded with microbeads.

A coating can be deposited on the beads by various known techniques such as contacting with a liquid reagent followed by drying or depositing from a vaporized reagent, for example in a fluidized bed and following this deposit of the coating impregnation with the catalyst, by bringing it into contact with the liquid or dissolved catalyst. However, according to a preferred method, the microbeads are brought into contact with a solution which contains both said organometallic compound and said catalyst and then the beads are dried. This procedure is particularly simple and rapid since it makes it possible to fix the catalyst to the glass in a single step.

Preferably, in order to fix said catalyst to the microbeads, a coating of an organometallic compound chosen from silanes, chromium complexes, titanium derivatives or polymers is formed on them. methoxysilyl group. Such compounds can be easily deposited in the form of a mono- or plurimolecular layer on the beads, by contacting with a solution. In addition, this process makes the beads adherent to the polymeric materials, which promotes the production of composite materials having good resistance to breaking by bending, for example. In the case of paints, generally applied λ. t 7.

in a thin layer, this process promotes the resistance of microbeads to abrasion removal.

In accordance with what has been indicated above, it may prove useful to use microbeads with a rough glass surface. Such beads can be obtained by mechanical frosting treatment but given their small size, it is easier to chemically frost them. This is why, according to a process according to the invention which is particularly effective for producing microbeads carrying a large quantity of catalyst, before the coating is formed, the surface of the beads is treated with a glass corrosion agent. Frosted beads with a rough surface are thus obtained which are capable of fixing more catalyst for the same average diameter. Such a process easily makes it possible to fix at least 3 times more catalyst on the balls than on balls at all other similar points but which have not undergone said corrosion treatment.

Such a process is preferably carried out by means of a solution containing fluorine ions, for example an aqueous solution of ammonium bifluoride. Such a process applies essentially to full microbeads, the microbubbles often having walls of a thickness too small to undergo such treatment.

There are various polymerization catalysts for accelerating or reducing the cure temperature of the polymerizable materials. For most unsaturated resins such as unsaturated polyester resins and their copolymers, the use of peroxide as a catalyst is generally recommended. The present invention therefore comprises a process characterized in that a catalyst of the peroxide type, for example benzoyl peroxide, is fixed on the balls.

The invention further extends to a process for the polymerization of a resin in the presence of a catalyst, characterized in that the catalyst is fixed to glass microbeads and the said microbeads are mixed with the material to be "I 8.

V

polymerize. In particular, said microbeads are mixed with a material chosen from unsaturated polyester resins, such as acrylic and urethane-acrylic resins. This process can be applied for molding parts from such materials in the presence of peroxide as catalyst and optionally an accelerator, at room temperature. This process can be applied to mold parts from an unsaturated polyester in solution in a copolymerizable monomer, for example, methacrylic oligourethane resins in methyl methacrylate used as solvent monomer or polyester resins mixed with a vinyl monomer, acrylic or allylic.

In such polymerization processes beads are used according to the first aspect of the invention, or obtained by a process according to the second aspect of the invention.

A particular application of the above-mentioned polymerization process as a third aspect of the invention, and of the microbeads according to the first aspect of the invention, resides in road marking. According to a particularly efficient process, in accordance with the third aspect of the invention, road marking is carried out using a polymerizable paint by depositing a layer of paint on the road and by spraying microbeads into the still liquid paint. or a mixture of microbeads containing microbeads, the surface of which has a coating comprising the polymerization catalyst necessary to harden this paint. This process makes it possible to draw lines, drawings, acronyms, etc. on the surface of the ground (road, parking lot, tarmac, etc.) perfectly clear and visible at night in the presence of light from vehicle headlights, a very short time and with minimal disruption to traffic. It has also been observed that the quantity of catalyst required to harden the paint was less when this technique was used with respect to the quantity generally required when dispersing the

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catalyst powder on the paint, according to the traditional technique. In addition, the present technique makes it possible to use a simple device comprising a spray gun for spraying liquid paint and a distributor of 5 microbeads, device which can be used in all circumstances both for marking with polymerizable paint and for marking with traditional emulsion paints.

Another particular application of the process according to the third aspect of the invention consists in a process for manufacturing parts made of polymer material, characterized in that a polymerizable resin is mixed with glass microbeads in accordance with the first aspect of the invention and said mixture is shaped before it hardens by poly-merisation. Such a method allows the quantity of catalyst necessary to carry out the polymerization to be measured very precisely before the resin-catalyst mixture is formed.

The present invention will now be described in more detail by way of the following examples.

Example 1:

Microbeads are made to be introduced into road marking paint. The microbeads have a diameter between 150 and 250 μ and a mean diameter (in number of particles) of 180 μ. The paint is an acrylic resin from Rohm, Plexilith SE 663.

Benzoyl peroxide is dissolved in toluene in an amount of 200 g / l of solvent. After a few minutes, silane A 174 (-methacryloxypropyltrimethoxysilane 30 from Union Carbide) is added. The solution containing the peroxide catalyst and the silane is poured onto the microbeads while the mixture is kept in continuous movement. After 15 minutes of stirring, the beads are dried at room temperature for 24 hours. The beads carry 0.075 gr of 35 silane per kilo and 8 gr of peroxide per kilo. The beads are then mixed with a small amount of a hydrophobic inorganic material inert to the treated beads, 10.

• i t 4 and with a large specific surface, in accordance with the teaching of the Belgian patent 900,932. This mixture is stored before being brought to the road marking location.

The paint is sprayed onto the road and the microbeads prepared as indicated above are projected onto it, at the rate of 1 part of balls for 1 part of paint (by weight). After 15 minutes, the paint is fully cured. The light reflection properties exhibited by this paint are not different from those of a similar paint but into which the catalyst and bare glass microbeads have been introduced separately. If the technique according to the prior art is used, in which the catalyst is supplied in separate form, it takes 2 to 3 times more than 15 peroxide to harden the paint in 15 minutes.

In a variant of the present example, 20% of the beads carrying the catalyst were replaced by beads treated with an agent which makes them hydrophobic and oleophobic, such as a fluorocarbon agent of the FC 129 type from 3M. The curing of the paint takes a few more minutes, but the retroreflective properties of the paint are improved due to the presence of the hydrophobic and oleophobic microbeads on the surface of the cured layer.

Example 2: Example 1 was repeated, but using a mixture of microbeads of different particle sizes. A mixture is used consisting of 1/3 of solid glass beads with a diameter between 40 and 80 μ, 1/3 with beads of diameter between 75 and 150 μ, 1/3 of beads with a diameter between 30 and 150 μ.

The amount of peroxide deposited on the beads was varied and the silane A 174 was replaced by an equivalent amount of a bonding agent with a methoxysilyl group, Polyvest 25 from Hüls.

The following table gives the hardening time of the acrylic paint in the presence of this mixture of beads, for a proportion of beads / resin of 1/1 by weight.

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Table 1

Amount of Polyvest peroxide 25 A 174 Setting time per kg of beads gr / kg gr / kg 5 4 - 0/07535 min.

3 - 0/075 15 min.

3 0.075 - 15 min.

Example 3:

Solid glass microbeads with an average diameter of 44 μ are treated with an aqueous solution of ammonium bifluoride. The beads which have undergone this treatment have an opaque white appearance. Their surface is rough.

These beads are mixed with a solution of silane A174 and benzoyl peroxide in toluene. There are thus deposited on the surface of the beads, 2 gr of silane and 8 gr of peroxide per kilo of beads.

Shaping is carried out by injection into a mold, of a methacrylic resin of the MDR 824 type from I.C.I. containing dimethyl-p-toluidine as an accelerator. The resin is at 20 ° while the mold is at 70 ° C. The resin is mixed, before injection, with 1.25 kg of beads per kilo of resin. The hardening of the molded part is observed after 50 seconds, at 70 ° C.

Example 4: 25 Glass microbeads of 44 μ in average diameter are treated in an identical manner to those of Example 3, with a glass corrosion agent and then with a mixture of silane and peroxide. In the present example, the peroxide with which the beads have been impregnated is methyl ethyl ketone peroxide.

100 parts by weight of these beads are mixed with 100 parts by weight of Epocryl 322 acrylic resin from Shell Chemical Cy. and 0.4 parts by weight of cobalt naphthenate as an accelerator (6% cobalt). The mixture is poured into a mold at 25 ° C. The gel time of the mixture is approximately 10 minutes and hardening is reached after 20 minutes.

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In a variant of this example, to the microbeads treated as above and carrying the polymerization catalyst, glass microbeads coated with a coating comprising a first substance are added which, if used alone, would make the beads hydrophobic while at the same time leaving oleophilic and a second substance which, if used alone would make the beads hydrophobic and oleophobic (these beads are treated according to the method described in Belgian patent 904,453) so as to obtain a good distribution of these beads in the resin and to confer to it reflective properties. Said mixture is used to mold retro-reflectors.

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Claims (20)

1. Glass microbeads characterized in that their surface carries a coating comprising a polymerization catalyst. 2. Microbeads according to claim 1 characterized in that said catalyst is adsorbed in a layer of coating material adhering to said surface. 3. Microbeads according to one of the preceding claims, characterized in that said catalyst is linked to a layer of an organometallic compound adhering to said surface. 4. Microbeads according to claim 3 characterized in that said organometallic compound adhering to said surface is chosen from silanes, chromium complexes, titanium derivatives or polymers containing a methoxysilyl group. 5. Microbeads according to any one of the preceding claims, characterized in that the glass surface carrying said coating is rough. 6. Microbeads according to any one of the preceding claims, characterized in that said catalyst is a peroxide. 7. Microbeads according to any one of the preceding claims, characterized in that their average diameter is between 50 μ and 650 μ. 25 8. Mixture of microbeads characterized in that it comprises glass microbeads according to any one of the preceding claims and glass microbeads carrying a coating which makes them hydrophobic and oleo-phobic. 30 9. Mixture according to claim 8 characterized in that at least 70% by weight consists of microbeads according to claims 1 to 7. 10. A process for treating glass microbeads during which a coating is deposited on the microbeads, characterized in that a coating of an organometallic compound is formed on the surface of the beads and is fixed to this i \ * 14 . * coating, a polymerization catalyst. 11. The method of claim 10 characterized in that the beads are brought into contact with a solution containing said organometallic compound and a polymerization catalyst and then the beads are dried. 12. Method according to one of claims 10 or 11 characterized in that a coating is formed of an organometallic compound chosen from silanes, chromium complexes, titanium derivatives or polymers containing a methoxysilyl group. 13. Method according to one of claims 10 to 12, characterized in that, prior to the formation of the coating, the surface of the beads is treated with a glass corrosion agent. 14. The method of claim 13, characterized in that the surface of the beads is treated with a solution containing fluorine ions. 15. Method according to one of claims 10 to 14 characterized in that a catalyst 20 of the peroxide type is fixed on the balls. 16. A method of polymerizing a resin in the presence of a catalyst, characterized in that the catalyst is fixed to glass microbeads and the said microbeads are mixed with the material to be polymerized. 17. The method of claim 16 characterized in that said microbeads are mixed with a material chosen from acrylic, ure-thane / acrylic polymerizable resins. 18. The method of claim 17 characterized in that said microbeads carry a coating comprising a peroxide. 19. A method of road marking using a polymerizable paint, characterized in that the paint is deposited on the road and a further 15 are sprayed into the paint. * * T 2 '* »liquid / microbeads or a mixture of microbeads according to one of claims 1 to 3. 19. Method according to one of claims 16 to 18 characterized in that said beads are obtained by a method according to one of claims 10 to 15. 20. A method of manufacturing parts made of polymer material, characterized in that a risable polymer resin-5 is mixed with glass microbeads according to one of claims 1 to 7 and said mixture is shaped before it hardens by polymerization.