FIELD OF THE INVENTION

The present invention is in the field of an improved 2-component polysulfide sealant composition, use of said composition, especially in or on locations which are preferably not closed, such as roads, and railways, on parking decks, and on airfields. The adhesive compo sition has an improved cure time.

BACKGROUND OF THE INVENTION

Closing roads, railways, or airfield platforms for maintenance is very expen sive, not to mention the nuisance it causes for both users as managers of the system. It is therefore preferred that maintenance should be performed as less as possible by using long lasting materials and systems, and when maintenance is necessary the downtime is best mini mized.

Polysulfide sealants have superior elasticity and durability over any bitumen- based materials. Due to their sulfur content they have a pseudoplastic character which allows to reduce and annihilate internal constant stresses which no other known elastic sealant does. In addition, polysulfide sealants have constant movement tolerances of 25% or more (as de fined in ISO 11600). It is therefore that lately there is a renewed interest in polysulfide seal ants for the above application to replace bitumen-based sealants.

Bitumen based sealants do not really cure. They are molten, applied in a liquid state, and after a cooling done period, they are ready. The time it takes to melt the sealants and the energy costs are often ignored as the melting can be done beforehand. Polysulfide sealants on the other hand are applied at ambient temperature and cure by a chemical pro cess, usually by oxidation with activated manganese dioxide, which is mixed in prior or dur ing application. After the mix is applied it may take three hours or (much) longer for the sealant to cure. The exact curing time typically depends on the accelerators added and on the ambient temperature. However, a cure time of shorter than three hours is desired.

To those working in the application of these poly sulfide sealants a little trick is known to increase the curing speed of the poly sulfide sealant. This is done by adding a tiny amount of water to the mixture after or better during mixing of the sealant and the manga nese dioxide containing curing agent. However, several strongly negative side effects are known by this use of free water. The rheology is jeopardized, the viscosity is increased, the flow decreased, and the cure of the surface of the sealant seems retarded, leading to a sticky surface which lasts for several hours. Due to the changes in rheology the water can not be added to any of the poly sulfide components prior to mixing with the curing agent. Also, the water can only be added, and therefore is only useful, in hand mixed applications, wherein the sealant is mixed prior to application. Hand mixable mixtures are, however, already slow reacting, and to include additional time between mixing and a curing state upon application is no longer possible. This window if often referred to as the open time or application win dow. Another problem associated by adding a little water to the polysulfide sealant is the ad dition of too much water. This will lead to an inferior sealant.

In machine applications, where both sealant and curing agent are mixed and ap- plicated at the same time, usually by pumping both in the desired ratio through a stationary mixer, a further addition of e.g. water cannot be done. Not only there would be the technical difficulty of adding and mixing three components into one flow, but the low viscosity of wa ter would leave mixing through a stationary mixer inadequate.

Some documents may be mentioned. US 2004/014878 A1 recites use of benzo ate plasticizers in two-component insulating glass adhesives/sealants based on poly sulfide polymers or polymercaptan polymers enables simpler production due to the low viscosity thereof. Improved miscibility of the two components and an improved rate of curing are ob served. In addition, the use of phthalate plasticizers, which may possibly cause an endocrinal effect in humans and animals, is avoided., EP 3 560900 A1 recites a multi-layered glass sealing material having excellent water vapor permeation resistance, gas barrier properties, and adhesion properties, and a multi-layered glass produced using such a sealing material. Specifically, provided is a sealing material for multi-layered glasses, including: a polysulfide resin A and a polyester resin B. US 3,499,864 A recites an improved one-part, stable, curable composition comprising SH group-containing liquid polymer (herein-after called polythiol polymer). More particularly, this invention relates to an improved one-part, elevated ambient temperature stable, curable polythiol polymer based composition which has incorporated therein (1) a dormant activatable, e.g. zinc oxide or zinc peroxide, curing agent (2) a desic cating, hygroscopic accelerating agent, (3) a zeolitic molecular sieve loaded with an amine compound accelerating agent, and (4) a stabilizing amount of elemental sulfur. WO 2006/029145 A2 recites preformed compositions in shaped form, for sealing apertures, com prising polymer blends comprising: a) at least one polysulfide component, and b) at least one polythioether component, and the use of these preformed compositions in shaped form to seal apertures are disclosed. In certain embodiments, the preformed compositions are electri cally conductive and are capable of shielding EMI/RFI radiation. The polymer blend in cludes a polysulfide component and a polythioether component. Other than some chemical similarities this document has not much to do with adhesive compositions, amongst others as it is preformed (and hence solid). RU 2330867 Cl recites a single-layer polymer coating for driveways of bridge floors of metallic and concrete bridges, and more specifically to poly mer compositions of obtaining and using the coating. Other than some chemical similarities this document has not much to do with adhesive compositions as it relates to coatings.

Therefore, a solution to increase the curing speed of in particular machine ap plied polysulfides is strongly desired.

It is therefore an object of the present invention to provide a polysulfide adhe sive which overcomes one or more of the above disadvantages, without jeopardizing func tionality and advantages.

SUMMARY OF THE INVENTION

The present invention relates to 2-component polysulfide sealant and use thereof. It has now been found that the above problems can be overcome by adding the water bounded in a physical or physical-chemical way, that is sorbed water, for exam ple by addition of the water absorbed in a zeolite. The addition of water did not influ ence the viscosity, or not noticeable. When this zeolite is used in the form of a powder this zeolite will not negatively influence the rheology. Now the water can already be added during the production stage without having to worry about the amount of water added or any negative effect associated by the addition of water before. The product, including the bounded water, is storage stable. Surprisingly the rheology is no longer jeopardized and the surface tackiness does no longer occur. By addition of water in this bound form a relative increase in curing speed (and likewise reduction of curing time) of 20-30% is achieved.

The present 2-component polysulfide sealant comprises in the first component, 10-70 wt.% of a liquid polysulfide resin, preferably 20-60 wt.%, more preferably 30-50 wt.%, 5-20 wt.% of at least one first plasticizer, preferably 7-18 wt.%, more preferably 10-15 wt.%, 5-40 wt.% a filler, preferably 10-35 wt.%, more preferably 20-30 wt.%, and optionally 0-5 wt.% sulphur, preferably 0.2-4 wt.%, more preferably 1-3 wt.%, 0-5 wt.% of an adhesion promotor, preferably 0.2-4 wt.%, more preferably 1-3 wt.%, 0-5 wt.% of a retarder, prefera bly 0.2-4 wt.%, more preferably 1-3 wt.%, 0-5 wt.% of a first dispersion agent, preferably 0.2-4 wt.%, more preferably 1-3 wt.%, and 0-5 wt.% of at least one further additive, prefera bly 0.2-4 wt.%, more preferably 1-3 wt.%, in the second component 1-5 wt.% of a curing agent, preferably 2-4 wt.%, more preferably 2.5-3 wt.%, such as manganese oxide; 1-5 wt.% of a second plasticizer, preferably 2-4 wt.%, more preferably 2.5-3 wt.%, and optionally 0-5 wt.% of a rheology modifier, preferably 0.2-4 wt.%, more preferably 1-3 wt.%, 0-5 wt.% of an accelerator, preferably 0.2-4 wt.%, more preferably 1-3 wt.%, 0-5 wt.% of sulphur, pref erably 0.2-4 wt.%, more preferably 1-3 wt.%, 0-5 wt.% of a second dispersion agent, prefer ably 0.2-4 wt.%, more preferably 1-3 wt.%, and 0.01-5 wt.% porous material, preferably 0.02-4 wt.%, more preferably 0.1-3 wt.%, even more preferably 0.3-2.5 wt.%, such as 0.4-2 wt.%, e.g. 0.7-1.4 wt.%, such as zeolite, and sorbed water, preferably 0.02-4 wt.%, more preferably 0.1-3 wt.%, even more preferably 0.3-2.5 wt.%, such as 0.4-2 wt.%, e.g. 0.7-1.4 wt.%, wherein all weight percentages are based on a total weight of the 2-component adhe sive.

In a second aspect the present invention relates to the use of the present adhesive for increased curing speed, for machine applying, in trafficable surfaces, such as roads, and railways, on parking decks, and on airfields.

Thereby the present invention provides a solution to one or more of the above- mentioned problems.

Advantages of the present description are detailed throughout the description.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates in a first aspect to a composition according to claim 1.

In an example of the present composition the water may be sorbed in the po rous material, such as in the zeolite.

In an example of the present composition the porous material may be pro vided as particles in powder form with an average particles size of <100 pm, preferably from 1-60 pm, more preferably 10-50 pm, even more preferably 15-40 pm, such as 20-30 pm.

In an example of the present composition the porous material may have an open pore volume of 30-70 vol.%, based on the total volume of the porous material.

In an example of the present composition an average pore size may be from 0.25-2.1 nm (2.5-21 A), preferably from 0.26-1.5 nm (2.6-15 A), more preferably 0.27-1.2 nm (2.7-12 A), even more preferably from 0.29-1.0 nm (2.9-10 A), such as from 0.3 -0.7 nm (3.0-7 A.

In an example of the present composition the porous material may be grinded, milled, sieved, and combinations thereof.

In an example of the present composition the filler may be selected from chalk, precipitated chalk, coated precipitated chalk, silica, alumina, carbon black, and combi nations thereof.

In an example of the present composition the first and second plasticizer each individually may be selected from benzoic acid esters, phthalic acid diesters, tereph- thalic acid diesters, chlorinated paraffins with a chain length >C8, benzoates, phthalates, ter- ephthalates, polyols, hydrogenated versions of phthalates, terephthalates and benzoates, and combinations thereof. In an example of the present composition the additives may be selected from catalysts, co-catalysts, rheology control agents, pigments, pigment pastes, HALS, UV stabi lizers, antioxidants, adhesion promotors, drying agents.

In an example of the present composition the adhesion promotor may be se lected from epoxy resins and glycidyl trimethoxy silane.

In an example of the present composition the first and second accelerator each individually may be selected from dialkyl thiurams with Cl to C7 alkyl, Cl to C7 aryl, or Cl to C7 alkaryl groups, metal-dialkyldithiocarbamates, with the metal preferably zinc, and with Cl to C7 alkyl, Cl to C7 aryl, or Cl to C7 alkaryl groups, mercaptobenzthiazole, and metal salts thereof, the metal being preferably zinc.

In an example of the present composition the retarder may be selected from branched, unbranched, saturated, and unsaturated organic acids with a chain length of 8-20 carbons, and combinations thereof, such as isostearinic acid.

In an example of the present composition the first dispersion agent may be selected from phosphoric acid polyesters.

In an example of the present composition the second dispersion agent may be selected from fatty alcohol esters, such as alcohol esters with >7 carbons.

In an example of the present composition the rheology modifier may be se lected from fumed silica, carbon black, and polyamide waxes, and combinations thereof.

In an example of the present composition the zeolite may be selected from CaA zeolites, CaX zeolites, NaX zeolites, NaY zeolites, and a natural zeolite of Nickel - Strunz class 09. G.

In an example of the present composition the first and second component may be provided in a weight ratio of 40:1 to 0.5:1, preferably 30:1 to 0.6:1, more preferably 25:1 to 0.7:1, such as 20:1 to 2:1.

In an example of the present composition the present composition may comprise a combination of the above.

The invention is further detailed by the accompanying figures and exam ples, which are exemplary and explanatory of nature and are not limiting the scope of the invention. To the person skilled in the art it may be clear that many variants, being obvious or not, may be conceivable falling within the scope of protection, defined by the present claims.

FIGURES

Figure 1 : The curing of the poly sulphide sealants is determined by an os cillation test on the Anton Pair MC302 Rheometer. By setting the storage modulus against time, the curing speed of the sealant can be determined.

Figure 2 Comparison of viscosities at different Shear rates of the B-side component of a poly sulphide kit with hydrated zeolite and with water. Water thicken ing of the kit in the low shear rates clearly increases.

EXAMPLES/EXPERIMENTS

The invention although described in detailed explanatory context may be best understood in conjunction with the accompanying examples.

During the development of a faster Sealer Fast (IPPB 1802 Faster Sealer Fast) it was noticed that the PS reaction could be significantly accelerated by adding hydrated zeolite. It was found that when water is added in pure form, this has a negative influence on the self levelling capacity of the poly sulfides. With water in zeolite this seemed to be less the case.

Experiments

To confirm that the B-side with hydrated zeolite flows better than with water addition, rheology tests were done. These have also been used to determine the curing of the sealant. For this purpose, the mixed A and B components were measured at a shear strain of 0.03% and a frequency of lHz.

In these rheology measurements it was first determined at which water content in the B-side the same speed is reached as with an addition of 1.5% hydrated zeolite in part B. Af terwards the viscosities at different Shear rates were compared with each other.

Results

In the amount of zeolite used are based on the total formula 0.25% water is present. Therefore, for the tests a water content of 0.25% and a tenth thereof were chosen.

Figure 1 shows that at a water content of 0.025% water in the B-side the same speed could be achieved as with 1.5% of the hydrated zeolite. It also becomes clear that curing with out water or zeolite is significantly slower and that a higher concentration of water will allow the sealant to cure even faster.

Figure 2 shows that the 0.025% water thickens the B-side in the low shear rates more than the zeolite. This can also be seen in the flow. The B-side with hydrated zeolite still flows well. The B-side with water no longer flows and can therefore no longer be used in the appli cation of the Saba Sealer Fast.

Conclusion

This research has proven that the wet zeolite in the B-side of the Saba Sealer Fast, at the same acceleration of the system, thickens the component less than water.

It should be appreciated that for commercial application it may be preferable to use one or more variations of the present system, which would similar be to the ones disclosed in the present application and are within the spirit of the invention.