WO2018074925A1

WO2018074925A1 - Two component adhesive with improved open time

Info

Publication number: WO2018074925A1
Application number: PCT/NL2017/050684
Authority: WO
Inventors: Wilco Bernardus WENNEKES; Ruud DE BLOCK; Kosma Mark VOORTMAN
Original assignee: Strongbond B.V.
Priority date: 2016-10-19
Filing date: 2017-10-19
Publication date: 2018-04-26
Also published as: NL2017639B1

Abstract

The present invention is in the field of a two component adhesive, a method of making said adhesive, and use of said adhesive. The first component of the two component adhesive comprises a silyl modified polymer and/or hybrid polymer, a filler, a primary catalyst, and a co-catalyst, wherein the co-catalyst typically is a Blockde R. primary or secondary amino silane, and is protected from water, whereas the second component comprises a silyl modified polymer and/or hybrid polymer, a molecular sieve, and water.

Description

Title Two component adhesive with improved open time

FIELD OF THE INVENTION

The present invention is in the field of a two component adhesive, a method of making said adhesive, and use of said adhesive .

BACKGROUND OF THE INVENTION

The present invention is in the field of a two component elastic adhesive which may be used as a kit or as a sealant; the elastic adhesive may also be referred to as a high modulus sealant. Sealants may be characterized by elongation properties. Elongation relates to a length to which a sealant can be stretched, e.g. expressed as a percentage of its original size. The term "modulus" relates to the tensile strength of a sealant at a given amount of elongation, as may be determined by ISO 8340:2005 or ASTM C1135. At 100 percent elongation, a high modulus may be defined as >0.4 MPa, and a low modulus as <0.4 MPa (ISO 11600), although the numbers given should not be considered as exact "boundaries". The modulus is considered to have a direct effect on the elongation capacity, since the lower the tensile strength, the easier the sealant may

stretch. High-modulus sealants are typically used where high strength is required and little movement is expected. Low-modulus sealants are typically used where movement capability is considered important. It is noted that typically one component of the two component adhesive comprises a non-reacted reactive polymer, and a second component comprises an activator c.q. a catalyst, which cures the polymer; in an alternative as a second component a reactive monomer, oligomer or polymer which is capable of reacting with the first component to form a cured product may be taken. In addition to two component adhesives also one component adhesives exits, which are typically activated by environmentally conditions, such as humidity, light, oxygen, etc. Below an indication is given of various require- ments of adhesives for a better understanding. It is noted that it is rather difficult to adapt characteristics of adhesives to specific requirements. It is intrinsically difficult to adapt properties of an adhesive, also referred to as "sealant", as improving a first characteristic may typically result in a deterioration of a second characteristic. For better understanding the difference between one-component (1C) and two-component (2C) adhesives/sealants is clarified. It is noted that the difference between these two is rather fundamental. A 1C system can react on its own given an auxiliary trigger or reactant. This trigger or reactant is usually oxygen or water from the air. Without (enough) of this trigger no reaction occurs and the product will not cure from its plastic state into an elastic one. This may happen for example when two plates, impenetrable for oxygen or moisture are glued full surface to another. There may be cure at the edges but there it stops. In a 2C system all necessary reactants are contained, not additional trigger or reactant is needed.

Therefore both parts will also have to be packed separately and typically mixed intensely before application. Both parts must be stable between production and use. When not properly mixed this will typically lead to inconsistencies in the cured material. Once mixed the curing reaction may start immediately, and therefore the material will have to be applied as soon as possible to prevent a too far cured product which will lead to difficulties in application and adhesion. A well-known system is an epoxy-adhesive where the epoxy is in one part and a curative amine is in the other part. Many other systems are known but all are based on this basic principle: once mixed, all necessary ingredients are there, nothing needs to get in or out. If a 2C product is used as an adhesive between the plates of the example all material, not just the edges but also the middle, will fully cure. Therefore for large surfaces (and other places where one cannot rely on the external trigger) 2C systems are preferred. From above it may be clear that the demands and challenges presented in a 1C product are quite different from a 2C product. Intermixing of components of a 1C and 2C product will typically not be considered by the skilled person; the two products may in fact be considered mutually incompatible .

General properties of adhesives are open time (working time to make a bond, where the surface still retains sufficient tack, which can range from seconds for fast-setting adhesives to infinity for pressure-sensitive adhesives) , set time (time to form a bond of acceptable strength) , dry time, (initial) tack {{ initial ) degree of surface stickiness of the adhesive) , applicability and adhesion to a diverse range of substrate surfaces, contactibility, flexibility of an adhesive film, temperature stability, storage stability, viscosity, and surface energy (influences wetting of different kind of sur^¬ faces) .

Adhesives often consist of one base material with various additives. For a two-component adhesive a first and second component, each component optionally comprising more than one constituent, are mixed before applying, such as by a spray- gun, a sealant-gun typically equipped with a means of mixing both components, and a static mixer. The first and second component can typically not be stored in a mixed form.

Some of the possible base materials, each having advantages and disadvantages, are reactive poly-urethanes, silicones, poly-sulphides, silane-terminated polymers, and various other copolymers .

Many of the prior art adhesives need to be bonded directly, typically within a few seconds, as the open time is relatively short. Thereafter one needs to wait until the adhesive has reacted and has obtained sufficient strength. That characteristic makes such an adhesive not suited for larger surfaces, or not very well accessible surfaces. Others may have a long open time and do not need to be bonded immediately; these consequently will suffer from an increased curing time thus also increasing the complete construction time of a to be bonded product .

It is often also important to have a high initial strength. For many prior art adhesive initial strength is not sufficient. One has to wait until the bond is sufficiently strong. Adhesives are preferably also temperature stable.

The present invention is in particular concerned with a curing time of a sealant. For instance, a standard one component (1C) sealant layer will cure at a speed of 3-4 mm/day. And further, the thicker the layer is, the slower this cure speed becomes. A partial solution for application of such adhesives is to use a two component adhesive. A (two) component adhesive curing time is usually defined as the time to achieve a given strength. A further problem is that after being applied a sealant cures much slower. 1C sealants are found to cure through the presence (and reaction with) humidity in air. When a sealant/adhesive is in an environment where no (further) humid- ity/moisture can enter (e.g. two metal or plastic plates), it does not cure or does not cure properly, e.g. only at the edges and not in a centre part of the sealant.

A further problem is that when there is no humidity in the air or the humidity is very low (e.g. after a frost period or at low temperatures, especially a 1C sealant cures very

slowly, in other words the cure will be retarded.

A solution to the problem could be to use a two component adhesive. However, this is found to introduce a new problem. Although now it is possible to cure relatively fast, there is hardly any open time left. For adhering smaller parts such might be of minor interest, but especially when bigger parts need to be glued together, for example side panels to trucks, big windows or multiple windows, at least part of the adhesive applied on a first part is already cured too far to obtain a good adhesion to the second part. The cure speed could be reduced by tuning other parameters, such as by adding less catalyst to a two component adhesive, or by using a slower catalyst, or by using another polymer with a different reactivity, but these measures are found to immediately reduce the

strength build up in time, it may reduce the cure speed, which will increase the production time on the product. This

strength reduction minimalizes the effect of the higher cure rate, which is in general the basic reason to use a 2C adhe^¬ sive .

Some prior art systems recite one component curable compositions, which will as a consequence suffer at least from the above disadvantages.

EP 2 088 173 Bl recites a curable one component composition made mainly of an organic polymer having a reactive silicon group, which is claimed to exhibit a good curability without using any organic tin compound substantially, and gives a cured product having a sufficient strength; and to provide a catalyst composition. The object is solved by a curable composition, comprising a polymer (A) having a silicon-containing group which can be crosslinked by forming a siloxane bond, a fluoride salt compound (B) , as well as a filler (C) in the form of a precipitated calcium carbonate surface-treated with an aliphatic acid. The curable composition is a one component system, wherein further the carbonate is considered to absorb any water (or likewise humidity or moisture) being present. The composition does not solve the problem of obtaining a long open time, followed by a short curing time, in the absence of virtually any humidity c.q. water.

EP 2 759 581 Al recites a one component sealant composition that includes a reactive silyl group-containing organic polymer, and gives a cured product having a low modulus and not having wrinkles or cracks on the surface even though the sealant includes as a curing catalyst a tetravalent tin compound, which is presumed to reduce recovery. The sealant composition is a one-component curable sealant composition including: a linear organic polymer (A) having a number average molecular weight of 11,000 to 30,000, and having an ethanol-elimination reactive silyl group at a molecular terminal; a tetravalent tin compound (B) ; and a plasticizer (C) . The composition does not solve the problem of obtaining a long open time, followed by a short curing time, in the absence of virtually any humidity c.q. water. In addition the sealant relates to a low modulus sealant.

US2016/0130402 Al recites moisture-curing compositions with increased storage stability based on compounds bearing silyl groups and use thereof. The one component curable composition comprises at least one silane compound having imine groups, and at least one pre-polymer comprising at least one silyl group. Also these compositions do not solve the above problems; only a longer storage stability is claimed.

It is noted that for two-component compositions, such as adhesives, generally speaking sub-components can not be interchanged between the two components, without severely risking to jeopardize functionality; even more in general it is to be expected that the two-component composition will not work at all, e.g. because certain chemical reactions will take place in at least one of the two-components, which are supposed to take place only after applying the two-components. WO 2008/133265 Al recites a two-component or multi-component curable composition characterized by having good workability, particularly long working life without deteriorating good adhesion to general-purpose bases. The curable composi- tion is obtained by mixing a base material (I) containing a polyether polymer (A) having a cross-linkable hydrolysable si- lyl group with a curing agent (II) containing a silanol condensation catalyst (B) and a silane coupling agent {C) . This curable composition is characterized in that the base material (I) contains an equivalent or excessive molar amount of water with respect to the hydrolysable silyl group, and the hydrolysis rate of the silane coupling agent (C) in the curing agent (II) is lower than the hydrolysis rate of a primary amine compound having a tri-methyoxy-silyl group. It is considered that upon mixing parts I and I I the viscosity will increase due to reactants being present; as such it is not likely that a suitable adhesive is obtained. The compositions mentioned in said document resemble the presently claimed ones only slightly; for instance examples comprise >50% filler, less than 10% si- lyl polymer, no co-catalyst, etc. The components A and B described are not separate parts of a 2C adhesive or sealant. Only when parts A and B would have been mixed a 1C system is achieved. That is, it still needs a trigger or external reac- tant to start the curing. If this system is applied between two sheets only the edges, where moisture from the air can penetrate, will cure. The rest will not. Also in view therefore this system cannot be regarded as similar to any 2C system. Moreover, as claimed, additional water as a trigger seems to be required according to the claims, to the part (I) of their invention, whereas, internally not consistent, the examples do not. Part (I) also contains the hydrolysable polymer and a 'cross-linkable hydrolysable silyl group'. This mixture is instable (as the water will hydrolyze the hydrolysable groups) and will immediately start to cure and can therefore not be seen as a 2C system. In a true 2C system water, pure or modified as in a paste, will never be part of any compound containing hydrolysable groups.

US 6,124,235 A recites an accelerator system in the form of a paste for cold crosslinking of polymers which harden on exposure to moisture by hydrolysis/condensation, comprising: (C) 0.01 to 10 parts of a catalyst for crosslinking the said polymers by poly-condensation, (E) 0.5 to 40 parts of a solid in- organic compound containing an up to 70% of water in the form of water of hydration and/or water adsorbed by capillary condensation, (F) 0 to 50 parts fillers, (D) a diluent or of a solvent, with dynamic viscosity 50 to 200,000 mPa.s. The accelerator system is used for accelerating silicone composi- tions which harden on exposure to the moisture in air. However nowhere a two-component system is mentioned.

EP 2 465 895 Al recites a composition comprising (a) a moisture-hardenable , silane-modified polymer, (b) a water-donating substance, which is surrounded by the shell of a sur- factant, and (c) an alcohol-binding metal oxide. This document can be considered as background art.

US 6,271,333 Bl recites a room temperature-curable one-part moisture curable composition exhibiting excellent storage stability as well as good adhesion is provided. It does not re- late to a two-component system.

Shin-Etsu and Gelest mention on their website various silane coupling agents. These are considered background art.

None of the above documents solves the problem of an improved curing time while maintaining a long open time, nor provide the further characteristics of the present invention, or at the best partly.

There is therefore a need for improved two component adhe- sives. It is an object of the present invention to provide an adhesive which overcomes one or more of the above disad- vantages, and a method of forming an adhesive, without jeopardizing f nctionality and advantages.

SUMMARY OF THE INVENTION

The present invention relates to an improved two component, typically elastic, adhesive according to claim 1, a method of applying said adhesive according to claim 11, and use of said adhesive according to claim 12. The present adhesive may be used as a kit or as a sealant; the present elastic adhesive is typically a high modulus sealant with a tensile strength >0.7 MPa, preferably 1-6 MPa, such as 1.5-5 MPa; by adapting the composition of the sealant the modulus can be adapted consequently, e.g. to 0.1-0.7 MPa, such as 0.3-0.7 or 0.4 MPa (ISO 11600) . Various other advantages are detailed throughout the description. As the adhesive is a two-component system, and as each component comprises further elements, these advantages must be due to synergistic effects of these element and components. None of the above cited documents relate to said advantageous effects. The mutual compatibility of the teachings of said documents is at least questionable.

The term "hybrid" is used in its normal meaning, namely

"something consisting of parts differing in origin or composition". A hybrid polymer is therefore a polymer consisting of an organic polymer part that is capable of reacting by an in^¬ organic part, namely silyl groups. In an example a polyether or a polyurethane polymer which is terminated with silyl groups {related to silicone polymers) to yield a high performance sealant having many of the beneficial characteristics of both polyurethanes and silicones is known in the field of ad- hesives (see "hybrid sealants" on the internet of May 2010) . A company as Wacker refers to these hybrid polymers as "silane- curing organic polymers", fully in line with the above. An ex^¬ ample of hybrid polymers are therefore silyl modified polymers (SMP) , also referred to as silane-modified polymers, modified- silane polymers, silane terminated polymers, etc. These are polymers (large, chained molecules) terminating with a silyl group. SMPs are the main components in solvent-free and isocy- anate-free sealant and adhesive products. Also books on dura^¬ bility and building sealants refer to hybrid polymer as consisting of a silicone modified polyether or polyurethane.

The term "catalyst" is considered to relate to a sub^¬ stance/product/entity to increase a rate of a chemical reaction due to its participation therein, which is not consumed in said reaction, and can continue to act repeatedly. Therefore only tiny amounts of catalyst are typically required.

The term "co-catalyst" is considered to relate to a catalyst supporting the main or first catalyst in its function.

The term "reactant" relates to a substance consumed in the course of a chemical reaction and hence (largely) disappearing as such over time. The first component of the present two component composition consists of 10-60 wt . % of a silyl modified polymer and/or hybrid polymer, preferably 20-50 wt.% polymer, such as 30-45 wt.%, e.g. 35-44 wt.%. It further consists of 10-50 wt.% of filler, preferably 20-45 wt.%, more preferably 30-40 wt.%. As an optional component a plasticizer is added in an amount of 0-30 wt.%, preferably 1-20 wt.%, more preferably 2-15 wt.%, even more preferably 3-10 wt.%, such as 4-7 wt.%. Further additives may be added in an amount of 0-15 wt.%, preferably 0.1-10 wt.%, more preferably 0.2-8 wt.%, even more preferably 0.3-7 wt.%, such as 0.4-6 wt.%. In addition 0.05 - 5 wt.% of a primary catalyst, preferably 0.1-3 wt.%, more preferably 0.5-2 wt.%, such as 1-2 wt.%, is present. The primary catalyst may be one or more of a tetravalent organotin compound, such as di- methyltin diacetate, dimethyltin bis (acetylacetonate) , dibu- tyltin dilaurate, dibutyltin maleate, dibutyltin phthalate, dibutyltin dioctanoate, dibutyltin bis (2-ethylhexanoate) , dibutyltin bis (methyl maleate), dibutyltin bis (ethyl maleate), dibutyltin bis (butyl maleate), dibutyltin bis(octyl maleate), dibutyltin bis (tridecyl maleate), dibutyltin bis (benzyl maleate), dibutyltin diacetate, dioctyltin bis (ethyl maleate), di- octyltin bis (octyl male-ate) , dibutyltin dimethoxide, dibutyltin bis (nonylphenoxide) , dibutyltin oxide, dibutyltin bis (acetylacetonate) , dibutyltin bis (ethyl acetoacetonate) , a reaction product of dibutyltin oxide and a silicate compound, a reaction product of dibutyltin oxide and a phthalic acid ester, di-octyltin dilaurate, dioctyltin diacetate, dioctyltin bis (acetyl-acetonate) , and reaction product of dioctyltin oxide and a silicate compound. The invention is characterized by a specific selection of co-catalyst, being different from the primary catalyst, wherein the co-catalyst is a blocked primary or secondary amino silane (ketimine silane or aldimine silane) with chemical formula { (R₃) (F ) C=N}_n (Rio) Si (ORi) 3-x (R2) x, wherein n=l or 2, and wherein Rio is an alkylene; the first component consists of 0.01 - 10 wt.% of a co-catalyst, preferably 0.02-5 wt.%, more preferably 0.1-3 wt.%, even more preferably 0.25-2 wt.%, such as 0.5-1 wt.%. Though e.g. WO 2008/133265 A in an example mentions a silane, said silane does not act as a (co- ) catalyst, but is involved in a reaction as a reactant. In view of the co-catalyst no or only a very small amount of water is present, such as less than 0.1 wt.%, preferably less than 0.05 wt.%. To guarantee that the presence of water is low enough to prevent premature reaction of saponification of the ketenimine or aldimine it is preferred to use a chemical drying agent, such as vinyl-trimethoxysilane, and vinyl-triethy- oxysilane. As a second component B consists of (bl) 10-90 wt.% of a silyl modified polymer and/or hybrid polymer, preferably 30-70 wt.%, such as 40-60 wt.%. The polymers of components A and B may be selected independently from one and another and may therefore be the same. Component B further consists of 10- 70 wt.% of a molecular sieve with a pore diameter of 0.25-0.6 nm (2.5-6 A), more preferably 30-50 wt.%, even more preferably 40-45 wt.%. The pore diameter is preferably 0.3-0.55 nm, more preferably 0.35-0.5 nm, such as 0.4-0.45 nm. Component B further consists of 1-25 wt.% water, preferably 1.5-20 wt.%, more preferably 2-12 wt.%. All wt.% are based on a total weight of component A or B, respectively. Note that component A preferably does not contain (free) water and component B does not contain a catalyst. Upon application or shortly before application the two components are mixed. Upon mixing the components (A) and (B) are present in a volume ratio A:B of 100:3 to 1:1, preferably 20:1 to 2:1, more preferably 15:1 to 3:1, such as 10:1 to 5:1, i.e. component A is on a volume basis typically present in a surplus with respect to component B. It is noted that for practical purposes the components are mixed in a volume ratio; the volume ratio is often quite similar to a weight ratio. The present two component adhesive provides certain advantages, as detailed throughout the description, and overcomes problems of the prior art.

It has now be found that when the cure-catalyst is a blocked aminosilane, an open time is created hardly affecting (or not significantly) the cure speed. The blocked amino-

silane (ketenimine silane) is in an example considered to react as follows:

i.e. upon addition of water an un-blocked amino-silane is formed, which latter amino-silane is found to cure the present adhesive. It is noted that the use of ketenime-blocked ami- nosilanes per se is well known. The chemistry may for instance be used for curing epoxy resins, thus making it possible to obtain 1C epoxy adhesives. The use of ketenimine-blocked silanes is also been described as a potential adhesive promo- tor, but to the knowledge of the inventors never as the co- catalyst for a 2C S-sealant. It is the unblocking of the present co-catalyst which is found to provide a good curing over time, and in addition it also provides typically a long open time, a good built-up in strength, good skin formation, reduc- tion of viscosity over time, and an increase of a viscosity ratio .

In a second aspect the present invention relates to a method of applying the present adhesive, comprising the steps of mixing the first and second component, applying the mixed composition to a surface, wherein after or during mixing, during application and after application the blocked amino silane reacts with water and forms an amino-silane under release of an aldehyde (R3=H) or a ketone (R3≠H) . It is noted that the steps of mixing and applying may be performed sequentially or (almost) simultaneously. The present amino-silane starts to perform its catalytic action/activation after being formed upon contact with water, and starts to cure the present composition.

In a third aspect the present invention relates to a use of the present two component adhesive in an adhesive or in a sealant .

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

Advantages of the present description are detailed through- out the description. The teachings and examples of the present invention may be combined into a further not specifically disclosed exemplary embodiment.

DETAILED DESCRIPTION OF THE INVENTION

In a first aspect the invention relates to a two component adhesive according to claim 1.

In an exemplary embodiment of the present adhesive R3 is independently selected from H, C1-C15 linear or branched alkyls, preferably Ci-Cs linear or branched alkyls, such as me- thyl, ethyl, propyl, butyl, isopropyl, isobutyl, tert-butyl, sec-butyl, pentyl, iso-pentyl, hexyl, iso-hexyl, heptyl, and octyl, C1-C15 linear or branched aromatic alkyls, C1-C15 linear or branched aralkyls, and linear or branched Ci-Cis-aryls, optionally containing one or more hetero atoms chosen from 0, S, and N.

In an exemplary embodiment of the present adhesive x is 0 or 1.

In an exemplary embodiment of the present adhesive R is independently selected from C1-C15 linear or branched alkyls, preferably Ci-Cs linear or branched alkyls, such as methyl, ethyl, propyl, butyl, isopropyl, isobutyl, tert-butyl, sec-butyl, pentyl, iso-pentyl, hexyl, iso-hexyl, heptyl, and octyl, C1-C15 linear or branched aromatic alkyls, C1-C15 linear or branched aralkylenes, and linear or branched Ci-Cis-aryls, op- tionally containing one or more hetero atoms chosen from 0, S, and N.

In an exemplary embodiment of the present adhesive Ri, and R2 are independently selected from hydrogen and Ci-Ca linear or branched alkyls, preferably C1-C4 linear or branched alkyls, such as methyl, ethyl, propyl, butyl, isopropyl, isobutyl, sec-butyl, and tert-butyl.

In an exemplary embodiment of the present adhesive Rio is independently selected from C1-C15 linear or branched alkyls, preferably Ci-Cs linear or branched alkyls, such as methyl, ethyl, propyl, butyl, isopropyl, isobutyl, tert-butyl, pentyl, iso-pentyl, hexyl, iso-hexyl, heptyl, and octyl, C1-C15 linear or branched aromatic alkyls, C1-C15 linear or branched

aralkyls, and linear or branched Ci-Ci5-aryls, optionally containing one or more hetero atoms chosen from O, S, and N.

In an exemplary embodiment of the present adhesive the first component has a viscosity of 100-20000 Pa.s, preferably 500-5000 Pa.s at a shear rate of 0.5 s^_1 (such as measured with a Rheosense microVISC (ISO 12092:2000, typically measured at T=23±0.5 °C) . In an exemplary embodiment of the present adhesive the second component has a viscosity of 10-2000 Pa.s at a shear rate of 0.5 s^_1 (such as measured with a Rheosense microVISC {ISO 12092:2000, typically measured at T=23+0.5 °C) .

In an exemplary embodiment of the present adhesive the mo^¬ lecular sieve is an aluminosilicate material, such as a zeolite, such as a zeolite 3A (0.6 K₂O:0.40 Na₂0:l Al₂O₃:2.0 ±0.1 Si0₂:xH₂0), zeolite 4A ( lNa₂0 : IAI2O3 : 2.0±0. lSi0₂ : xH₂0) , and zeo^¬ lite 5A (0.80CaO:0.20Na₂O:lAl₂O₃:2.0±0.1SiO₂:x H₂0) (e.g. Sigma Aldrich AL-143, such as 208574, 208582, 208590, 208604,

208612, and 208620) .

In an exemplary embodiment of the present adhesive the filler is selected from chalk, precipitated chalk, coated precipitated chalk, silica, carbon black, and combinations thereof. It is preferred to use fillers with a low amount of water; typically a water percentage is checked upon the present application of the filler. In principle fillers as chalk could absorb water as well, but in practice it is found that such does not happen significantly. The present filers there- fore function mainly as fillers only.

In an exemplary embodiment of the present adhesive the plasticizer is selected from benzoates, phthalates, tereph- thalates, polyols, hydrogenated versions of phthalates, ter- ephthalates and benzoates, and combinations thereof. In view of toxicity polyols, terephthalates and benzoates are preferred. Examples of suitable terephthalates are dibutyl ter- ephthalate, dipropyl terephthalate, and dipentyl tereph- thalate. Examples of suitable benzoates are mono-esters from benzoic acid and a Cs-Ci6 alcohol, preferably wherein the alco- hoi is a C9-C11 alcohol, preferably a C10 alcohol. Suitable polyols are PPG-2000, PPG 1000, and PPG2500.

In an exemplary embodiment of the present adhesive the additives are selected from catalysts, rheology control agents, pigments, pigment pastes, anti-oxidants, HALS, UV stabilizers, adhesion promotors, drying agents, fungicide, bactericide, and combinations thereof. A typical amount of additive is 0.05-0.5 wt.% per additive, such as 0.1-0.2 wt . % (independently of one and another) . In an exemplary embodiment of the present adhesive the polymer comprises a functionalized polyether backbone with meth- oxysilane terminal groups, the modified silyl polymer comprises one or more -An-D-SiXYZ end groups wherein:

A is a divalent linking group comprising at least one hetero atom, D is a divalent hydrocarbon residue with 1-12 C-atoms, X, Y, Z are each independently substituents on the Si atom, and are independently selected from Ci-Cs alkyl, Ci-Cs alkoxy, Ci-Cs acyloxy, and wherein at least one of the substituents X, Y, Z is a Ci-Cs alkoxy or Ci-Cs acyloxy, and n is 0 or 1.

In an exemplary embodiment of the present adhesive in the polymer A is preferably selected from oxygen, -NR'-, amide, carbamate, urea, imino, carboxylate, carbamoyl, amidino, and carbonate, wherein R'=H or C1-C4 alkyl, preferably oxygen or - NH-.

In an exemplary embodiment of the present adhesive in the polymer D is preferably selected from alkylene residues, such methylene, ethylene, and n-propylene.

In an exemplary embodiment of the present adhesive the polymer is selected from at least one of MS-polymersTM, dimethoxysilyl terminated polyether, trimethoxysilyl terminated polyether, S203H, S303H,S227, S327, SAX 220, SAX 260, SAX350, SAX400, SAT010, SAX015, SAX115, SAT145, MAX602, MAX923, AX951,

SAX750, SAX510, SAX520, SAX 530, SAX540, SAX580, SAX590, MAX 451, MAX 480, MAX850; Desmoseal®, for example S XP 2458, S XP 2636, S XP 2749, S XP 2774, S XP 2821; Geniosil® for example STP-E10, STP-E15, STP-E30, STP-E35, Evonik Polymer for example ST47, ST 48, ST 77, ΞΤ 61, ST 61 LV, ST 81, ST 80 and TEGOPAC® , for example Seal 100, Bond 150, and Bond 250.

In an exemplary embodiment of the present adhesive the primary catalyst is selected from one or more of a tetravalent organotin compound, such as dimethyltin diacetate, dimethyltin bis (acetylacetonate) , dibutyltin dilaurate, dibutyltin male- ate, dibutyltin phthalate, dibutyltin dioctanoate, dibutyltin bis (2-ethylhexanoate) , dibutyltin bis (methyl maleate) , dibutyltin bis (ethyl maleate) , dibutyltin bis (butyl maleate) , dibutyltin bis{octyl maleate), dibutyltin bis{tridecyl maleate), dibutyltin bis (benzyl maleate), dibutyltin diacetate, dioctyltin bis (ethyl maleate) , dioctyltin bis (octyl male-ate) , dibutyltin dimethoxide, dibutyltin bis (nonylphenoxide) , dibu- tyltin oxide, dibutyltin bis (acetylacetonate) , dibutyltin bis (ethyl acetoacetonate) , a reaction product of dibutyltin oxide and a silicate compound, a reaction product of dibu- tyltin oxide and a phthalic acid ester, di-octyltin dilaurate, dioctyltin diacetate, dioctyltin bis ( acetylacetonate ) , and reaction product of dioctyltin oxide and a silicate compound.

In a second aspect the invention relates to a method according to claim 12.

In an exemplary embodiment of the present method the first and second component are mixed in a weight ratio A:B of 100:3 to 1:1. Typically a first surface may be provided with the present adhesive in an amount of 150-600 gr/m², such as 250-500 gr/m².

In an exemplary embodiment of the method the adhesive is applied with a sealant gun.

In an exemplary embodiment of the method the adhesive is applied at a temperature of 5 °C-45 °C, preferably 10 °C-35 °C. Therewith the present adhesive can be applied at given working temperatures.

In a third aspect the invention relates to a use according to claim 14.

In an exemplary embodiment the present use is in a method for improving at least one of open time, built-up strength, preferably to more than 1 N/rara², skin formation, reducing viscosity over time, and maintaining a viscosity ratio (viscosity after 14 days : viscosity after 3 days @40°C) below 1.1, preferably below 1.05. Therewith a storage stable adhesive is provided.

In an exemplary embodiment the present use is for sealing or bonding joints in transport vehicles, such as cars, trucks, busses, trains, vans, motorhomes, caravans, and trailers, ships, such as yachts, ships, and boats, or for adhering a first surface to a second surface. It may also be used for sealants for buildings, such as homes, sheds, factories, offices, and high rise buildings, road-infrastructure, such as viaducts, bridges, and fly-overs.

The invention is further detailed by the accompanying fig- ures and examples, 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.

BRIEF DESCRIPTION OF THE FIGURES

Figs, la-f show various characteristics of prior art adhe- sives comprising a varying amount of aminosilane (AMEO) .

Figs. 2a-f show various characteristics of present adhe- sives comprising a varying amount of blocked aminosilane

(AMEO) .

DETAILED DESCRIPTION OF THE FIGURES

Figs, la-f show various characteristics of prior art adhe- sives comprising a varying amount of aminosilane (AMEO) for an adhesive composition shown in the below examples. In fig. la the amount of amino silane is given on the vertical axis (wt.% of total composition) . On the horizontal axis the amount of catalyst is given (wt.%). The viscosity after 3 days of the tested two-component adhesive is given in Pa*s. As can be con- eluded from the figure is that within the given catalyst range (0.5-3 wt.%) the viscosity only depends on the amount of AMEO, from about 1200 Pa*s (top region) to about 2600 Pa*s (bottom region) . Fig. lb gives the viscosity after 14 days, varying from about 800 Pa*s (top region) to about 3200 Pa*s (bottom region) indicating that the adhesive is stable over time. Fig. lc shows the viscosity ratio of the results after 14 days (fig la) and 3 days {fig lb) which varies form 1 (top region) to 1.3 (bottom region) indicating that the adhesive is stable over time. Fig. Id shows the strength build-up (N/mm²) in 24 hours; it is clear that a higher amount of catalyst (from left to right) increase the strength significantly, whereas the amount of AMEO shows a minor but noticeable effect in this respect; in a left bottom region the strength is about 0.4 N/mm², whereas in a right top section it is 1.2 N/mm². From fig. le it can be seen that at the same time the open time (in minutes) decreases from 60 (top left) to less than 10 minutes (bottom right) , which is considered too short for several applications. Fig. If shows that there is not much difference in through cure speed, varying from 3 mm (top) to 3.5 mm (bottom) and which cure speed is only found to depend on the amount of AMEO slightly. It is shown that the time it takes to reach a strength of 1 MPa in the cured sealant. This varies from 25 hours (left) to less than 5 hours showing the influence of the catalyst on the cure time and also showing that this is independent of the aminosilane.

Figs. 2a-f show various characteristics of present adhe- sives comprising a varying amount of blocked aminosilane (3- (1, 3-dimethylbutylidene) aminopropyltriethoxysilane) for an ad- hesive composition of the examples below. In fig. 2a the amount of amino silane is given on the vertical axis (wt.% of total composition) . On the horizontal axis the amount of catalyst is given (wt.%). The viscosity after 3 days of the tested two-component adhesive is given in Pa*s. As can be concluded from the figure is that within the given catalyst range (0.5-3 wt.%) the viscosity not only depends on the amount of AMEO but also on the amount of catalyst (a.o. the present blocked amino silane) , from about 1200 Pa*s (top region) to about 2100 Pa*s (bottom region) . Fig. 2b gives the viscosity after 14 days, varying from about 500 Pa*s (top region) to about 3200 Pa*s (bottom region) indicating that the adhesive is stable over time, now being fully dependent on the amount of AMEO only. Fig. 2c shows the viscosity ratio (between freshly applied and older sealant after 14 days at 313 K (40 °C) ) which varies from 1 (top left region) to 1.3 (bottom middle region) . This again shows the stability of the formula of the present invention. Fig. 2d shows the strength build-up (N/mm²) in 24 hours; it is clear the strength built-up has now become completely dependable on the level of catalyst and is completely inde- pendent of the amount of blocked aminosilane; in a left region the strength is about 0.3 N/mm², whereas in a right section it is 1.1 N/mm². The strength-built-up is in the same level as with the prior art adhesive with AMEO. From fig. 2e it can be seen that the skin formation is almost independent of the amount of blocked aminosilane. But even more important the decrease is now from 180 to 20 minutes (instead of 60 to 10 for the prior art) . This provides the option to tune this characteristics over a wide and acceptable range of time. So the use of a blocked aminosilane allows the choice of a long open time and high speed strength built-up. For example the open time for a strength built-up of 0,95 N/mm² increase from 18 minutes for standard AMEO to 39 minutes with a blocked aminosilane of the present invention. Fig. 2f shows that there is some dif- ference in through cure speed, varying from 2.7 mm (top left and right) to 3.5 mm (bottom middle) and which cure speed is thus found to depend on the amount of AMEO and slightly on the amount of catalyst. It is shown that the time it takes to reach a strength of 1 MPa in the cured sealant. This varies from 35 hours (left) to less than 10 hours showing the influence of the catalyst on the cure time and also showing that this is independent of the aminosilane. Combining the information of figures le and 2e with figures If and 2f show that while the open time has been greatly enhanced only a limited effect is found on the cure time and strength build-up.

EXAMPLES

Part A was prepared as follows (experiments 1-4)

The differences in initial reactivity may best be shown by the skin formation time of the part A

From these data it is easily seen that the experiments containing a blocked aminosilane have a very low initial reactivity.

Part B was made by mixing: 50 mass% MS-polymer, 40% Zeolite 3 Angstrom and 10% water.

When part A and Part B are now mixed together a new window of formulation opportunities arises. This is shown in the figures, e.g. figures le and 2e where it can be seen that the open time may now be varied from an initial open time of 10-50 minutes to 20 to >180 minutes by a further variation of the amount of catalyst.

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.

Claims

1. Two component adhesive composition consisting of a first component (A) comprising

(al) 10 - 60 wt . % of a silyl modified polymer and/or hybrid polymer,

(a2) 10 - 50 wt.% of filler,

(a3) 0 - 30 wt.% of a plasticizer,

(a4) 0 - 15 wt.% additives,

(a5) 0.05 - 5 wt.% of a primary catalyst, preferably 0.1-3 wt.%, more preferably 0.5-2 wt.%, such as 1-2 wt.%,

(a6) 0.01 - 10 wt.% of a co-catalyst, preferably 0.02-5 wt.%, more preferably 0.1-3 wt.%, even more preferably 0.25-2 wt.%, such as 0.5-1 wt.%,

wherein the co-catalyst is a blocked primary or secondary amino silane {ketimine silane or aldimine silane) with chemical formula { (R₃) (R₄) C=N}_n (Rio) Si (ORi) 3-x (R2) x, wherein n=l or 2, and wherein Rio is an alkylene,

(a7) 0.1-5 wt.% of a drying agent,

as a second component (B) consisting of

(bl) 10-90 wt.% of a silyl modified polymer and/or hybrid polymer, preferably 30-70 wt.%,

(b2) 10-70 wt.% of a molecular sieve with a pore diameter of 0.25-0.6 nm (2.5-6 A), more preferably 30-50 wt.%,

(b3) 1-25 wt.% water, preferably 1.5-20 wt.%, more preferably 2-12 wt.%,

wherein R3 is independently selected from H, C1-C15 linear or branched alkyls, C1-C15 linear or branched aromatic alkyls, Ci- Ci5 linear or branched aralkyls, and linear or branched C1-C15- aryls, and/or

x is 0 or 1, and/or

wherein R₄ is independently selected from C1-C15 linear or branched alkyls, C1-C15 linear or branched aromatic alkyls, Ci- Ci5 linear or branched aralkylenes, and linear or branched Ci- Ci5-aryls,

wherein all wt.% are based on a total weight of component A or B, respectively,

wherein upon mixing the components (A) and (B) are present in a volume ratio A: B of 100:3 to 1:1, preferably 20:1 to 2:1, more preferably 15:1 to 3:1, such as 10:1 to 5:1.

2. Two component composition according to claim 1, wherein R3 is independently selected from Ci-Cs linear or branched alkyls, such as methyl, ethyl, propyl, butyl, isopro- pyl_f isobutyl, tert-butyl, pentyl, iso-pentyl, hexyl, iso- hexyl, heptyl, and octyl, optionally containing one or more hetero atoms chosen from 0, S, and N, and/or

wherein R is independently selected from Ci-Ce linear or branched alkyls, such as methyl, ethyl, propyl, butyl, isopro- pyl_/ isobutyl, tert-butyl, pentyl, iso-pentyl, hexyl, iso- hexyl, heptyl, and octyl, optionally containing one or more hetero atoms chosen from 0, Ξ, and N, and/or

wherein Ri, and R₂ are independently selected from hydrogen and Ci-Cs linear or branched alkyls, such as methyl, ethyl, propyl, butyl, isopropyl, isobutyl and tert-butyl, and/or

wherein Rio is independently selected from C1-C15 linear or branched alkyls, preferably Ci-Cs linear or branched alkyls, such as methyl, ethyl, propyl, butyl, isopropyl, isobutyl, tert-butyl, pentyl, iso-pentyl, hexyl, iso-hexyl, heptyl, and octyl, C1-C15 linear or branched aromatic alkyls, C1-C15 linear or branched aralkyls, and linear or branched Ci-Cis-aryls , optionally containing one or more hetero atoms chosen from 0, S, and N .

3. Two component composition according to any of the preceding claims, wherein the first component has a viscosity of 100-10000 Pa.s (ISO 12092:2000, at T=23±0.5 °C) , preferably 500-5000 Pa.s, and/or wherein the second component has a vis^¬ cosity of 10-1000 Pa.s (ISO 12092:2000, at T=23+0.5 °C) .

4. Two component composition according to any of the preceding claims, wherein the molecular sieve is an alumino- silicate material, such as a zeolite, such as a zeolite 3A (0.6 K₂O:0.40 Na20:l AI2O3 : 2.0±0. IS1O2 : xH₂0) , zeolite 4A

(lNa2O:lAl₂O₃:2.0±0.1SiO2:xH2O) , and zeolite 5A

(0.80CaO:0.20Na2O:lAl₂O₃:2.0+0.1SiO2:x H₂0) .

5. Two component composition according to any of the preceding claims, wherein the filler is selected from chalk, precipitated chalk, coated precipitated chalk, silica, carbon black, and combinations thereof, and/or

wherein the drying agent is selected from methoxy silanes and ethoxy silanes, preferably trimethoxy silanes and triethoxy silanes, such as vinyl-trimethoxysilane, and vinyl-triethyox- ysilane .

6. Two component composition according to any of the preceding claims, wherein the plasticizer is selected from benzoates, phthalates, terephthalates , polyols, hydrogenated versions of phthalates, terephthalates and benzoates, and com^¬ binations thereof.

7. Two component composition according to any of the preceding claims, wherein the additives are selected from catalysts, rheology control agents, pigments, pigment pastes, anti-oxidants (examples in the description) , HALS, UV stabilizers, adhesion promotors, fungicide, bactericide, and combinations thereof.

8. Two component composition according to any of the preceding claims, wherein the polymer comprises a functional- ized polyether backbone with methoxysilane terminal groups, the modified silyl polymer comprises one or more -An-D-SiXYZ end groups wherein:

A is a divalent linking group comprising at least one hetero atom,

D is a divalent hydrocarbon residue with 1-12 C-atoms,

X, Y, Z are each independently substituents on the Si atom, and are independently selected from Ci-Cs alkyl, Ci-Cs alkoxy, Ci-Cs acyloxy, and wherein at least one of the substituents X, Y, Z is a Ci-Cs alkoxy or Ci-Ce acyloxy, and

n is 0 or 1,

wherein A is preferably selected from oxygen, -NR'-, amide, carbamate, urea, imino, carboxylate, carbamoyl, amidino, and carbonate, wherein R'=H or C1-C4 alkyl, preferably oxygen or - NH-, and/or

wherein D is preferably selected from alkylene residues, such methylene, ethylene, and n-propylene.

9. Two component composition according to any of the preceding claims, wherein the polymer is selected from at least one of dimethoxysilyl terminated polyether, and tri- methoxysilyl terminated polyether.

10. Two component composition according to any of the preceding claims, wherein the primary catalyst is selected from one or more of a tetravalent organotin compound, such as dimethyltin diacetate, dimethyltin bis (acetylacetonate ) , dibu- tyltin dilaurate, dibutyltin maleate, dibutyltin phthalate, dibutyltin dioctanoate, dibutyltin bis (2-ethylhexanoate) , dibutyltin bis (methyl maleate) , dibutyltin bis (ethyl maleate) , dibutyltin bis (butyl maleate), dibutyltin bis (octyl maleate), dibutyltin bis (tridecyl maleate), dibutyltin bis (benzyl maleate), dibutyltin diacetate, dioctyltin bis (ethyl maleate), di- octyltin bis (octyl maleate), dibutyltin dimethoxide, dibutyltin bis (nonylphenoxide) , dibutyltin oxide, dibutyltin bis (acetylacetonate) , dibutyltin bis (ethyl acetoacetonate) , a reaction product of dibutyltin oxide and a silicate compound, a reaction product of dibutyltin oxide and a phthalic acid es^¬ ter, di-octyltin dilaurate, dioctyltin diacetate, dioctyltin bis (acetylacetonate ) , and reaction product of dioctyltin oxide and a silicate compound.

11. Two component composition according to any of the preceding claims, wherein the first component (A) consists of (al) 10 - 60 wt.% of a silyl modified polymer and/or hybrid polymer,

(a2) 10 - 50 wt.% of filler,

(a3) 0 - 30 wt.% of a plasticizer,

(a4) 0 - 15 wt.% additives,

(a5) 0.05 - 5 wt.% of a primary catalyst,

(a6) 0.01 - 10 wt.% of a co-catalyst, and

(a7) 0.1-5 wt.% of a drying agent.

12. Method of applying a two component composition ac cording to any of claims 1-11, comprising the steps of mixing the first and second component,

applying the mixed composition to a surface,

wherein after or during mixing, during application and after application the blocked amino silane reacts with water and forms an amino-silane under release of an aldehyde (R.3=H) or a ketone (R3≠H) .

13. Method according to claim 12, wherein the first and second component are mixed in a weight ratio A:B of 100:3 to 1:1.

14. Use of a composition according to any of claims 1 11, in an adhesive or in a sealant.

15. Use according to claim 14, in a method for improving at least one of open time, built-up in strength, skin formation, reducing viscosity over time, and maintaining a viscosity ratio (viscosity after 14 days : viscosity after 3 days @40°C) below 1.1, preferably below 1.05.

16. Use according to any of claims 14-15 for sealing or bonding joints in transport vehicles, such as cars, trucks, busses, trains, vans, motorhomes, caravans, and trailers, ships, such as yachts, ships, and boats, or for adhering a first surface to a second surface.