Solvent-based primer having a long open time and improved adhesion

Abstract

Adhesion promoter compositions, containing: a) between 40 and 80 parts by weight of a binder composition, including i) 20-40 wt % of at least one silane-terminated polyurethane polymer STP, which can be obtained from at least one polyol P, aliphatic polyisocyanate I and organosilane OS1, ii) 4-20 wt % of at least one organosilane OS2 and/or organotitanate OT, iii) 0-3 wt % of at least one desiccant, iv) 40-80 wt % of solvent L1; b) between 0-30 parts by weight of industrial carbon black; c) between 0-1 parts by weight of UV marker; d) so much of solvent L2 that sum of a)-d) is 100 parts by weight; OS1 having secondary amino, mercapto or hydroxyl group on organic moiety and the at least one STP having been produced in absence of OS2, and the at least one P having an average OH functionality of at least 2 and equivalent weight of at most 500.

Claims

1. An adhesion promoter composition containing a) between 40 and 80 parts by weight of a binder composition comprising i) 20% to 40% by weight based on the binder composition of at least one silane-terminated polyurethane polymer STP obtainable from at least one polyol P, at least one aliphatic polyisocyanate I and at least one organosilane OS1 in the presence of a catalyst K, ii) 4% to 20% by weight based on the binder composition of at least one organosilane OS2 and/or organotitanate OT, iii) 0% to 3% by weight based on the binder composition of at least one drying agent, iv) 40% to 80% by weight based on the binder composition of a solvent L1; b) between 0 and 30 parts by weight of carbon black; c) between 0 and 1 parts by weight of UV marker; d) sufficient of a solvent L2 for a) to d) to sum to 100 parts by weight; wherein the organosilane OS1 comprises a secondary amino group, a mercapto group or a hydroxyl group on the organic radical, the at least one silane-terminated polyurethane polymer STP was produced in the absence of the organosilane OS2, the at least one polyol P is selected from the group of polycarbonate polyols, polyester polyols or poly(meth)acrylate polyols, and the at least one polyol P has an average OH functionality of at least 2 and an equivalent weight of not more than 500.

2. The adhesion promoter composition as claimed in claim 1, wherein the organosilane OS2 and/or organotitanate OT comprises at least one, compounds selected from the group comprising aminosilanes, hydroxysilanes, epoxysilanes, mercaptosilanes, isocyanuratosilanes, reaction products of amines and epoxysilanes, reaction products of aminosilanes and epoxides, reaction products of aminosilanes and epoxysilanes, reaction products of isocyanates and aminosilanes, reaction products of isocyanates and hydroxysilanes, tetraalkoxytitanates, dialkoxybisacetylacetonatotitanates and mixtures, hydrolyzates, partial hydrolyzates and/or condenzates of these compounds.

3. The adhesion promoter composition as claimed in claim 1, wherein the polyisocyanate I comprises isophorone diisocyanate.

4. The adhesion promoter composition as claimed in claim 1, wherein the molar ratio of isocyanate groups of the polyisocyanate I to hydroxyl groups of the polyol P is between 2 and 4.

5. The adhesion promoter composition as claimed in claim 1, wherein the polyol P has an average OH functionality of between 2 and 5.

6. The adhesion promoter composition as claimed in claim 1, wherein the at least one polyol P has an equivalent weight of 100 to 500.

7. The adhesion promoter composition as claimed in claim 1, wherein the solvents L1 and L2 are selected from the group comprising methyl acetate, ethyl acetate, butyl acetate, isopropyl acetate, 1-methoxy-2-propyl acetate, 3-methoxy-n-butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethylbenzene and mixtures thereof.

8. The adhesion promoter composition as claimed in claim 1, wherein the catalyst K comprises a tin or zirconium complex.

9. The adhesion promoter composition as claimed in claim 1, containing a) between 50 and 70 parts by weight of the binder composition comprising i) 25% to 35% by weight based on the binder composition of the at least one silane-terminated polyurethane polymer STP obtainable from the at least one polyol P, the at least one aliphatic polyisocyanate I and the at least one organosilane OS1 in the presence of the catalyst K, ii) 4% to 16% by weight based on the binder composition of the at least one organosilane OS2 and/or organotitanate OT, iii) 0.5% to 1.5% by weight based on the binder composition of the at least one drying agent, iv) 50% to 70% by weight based on the binder composition of the solvent L1; b) between 5 and 15 parts by weight of carbon black; c) between 0.1 and 0.5 parts by weight of UV marker; d) sufficient of the solvent L2 for a) to d) to sum to 100 parts by weight.

10. A method of adhesive bonding or of sealing comprising the steps of i) applying an adhesion promoter composition according to claim 1 to a substrate S1 to be adhesively bonded or sealed ii) applying an adhesive or sealant to the composition present on the substrate S1 iii) contacting the adhesive or sealant with a second substrate S2; or i′) applying an adhesion promoter composition according to claim 1 to a substrate S1 to be adhesively bonded or sealed ii′) applying an adhesive or sealant to the surface of a second substrate S2 iii′) contacting the adhesive or sealant with the composition present on the substrate S1; or i′) applying an adhesion promoter composition according to claim 1 to a substrate S1 to be adhesively bonded or sealed ii″) applying an adhesive or sealant between the surfaces of substrates S1 and S2, wherein the second substrate S2 is made of a material which is identical or different to that of the substrate S1.

11. The method as claimed in claim 10, wherein at least one of the substrates S1 and S2 comprises glass, metal or ceramic.

12. The method as claimed in claim 10, wherein the adhesive or sealant is a polyurethane adhesive containing at least one isocyanate-comprising polyurethane prepolymer or is an adhesive based on silane-functional polymers.

13. An article produced by a method as claimed in claim 10.

14. The article as claimed in claim 13, wherein the article is a built structure, an industrial good or a mode of transport.

Description

EXAMPLES

(1) The following adhesion promoter compositions were produced according to table 1 by adding the adhesion promoter to the carrier medium and stirring well under nitrogen.

(2) The following substances and designations were used:

(3) Employed Polyols P for Production of Polymer STP

(4) TABLE-US-00001 TABLE 1 Employed polyols P. OH Equiv- num- Function- alent Name Category ber ality weight Kuraray C590 Polycarbonate polyol 229 2 245 Desmophen C1100 Polycarbonate polyol 115 2 488 Desmophen C1200 Polycarbonate polyol 56 2 1002 Oxymer M112 Polycarbonate polyol 112 2 501 Capa 3031 Polyester polyol 560 3 100 Capa 4101 Polyester polyol 218 4 257 Dynacoll 7131 Polyester polyol 35 2 1603 Baycoll 670 Polyester polyol 141 3.2 398 Baycoll AV 2113 Polyester polyol 109 3.2 515 Baycoll AS 2060 Polyester polyol 60 2.7 935

(5) The polyols in table 1 were used as polyol P for producing the exemplary silane-terminated polyurethane polymers STP.

(6) Further Raw Materials Employed

(7) The raw materials of table 2 were also used for production of the exemplary compositions.

(8) TABLE-US-00002 TABLE 2 Further raw materials employed. Manufac- Name Function Chemical name turer Silquest Organosilane Bis(trimethoxysilylprop- Momentive A1170 yl)amine Silquest A189 OS2 3- Momentive Mercaptopropyltrimethoxy- silane Silquest A- Tris(3-trimethoxysilyl- Momentive Link 597 propyl) isocyanurate Tyzor IBAY Organo- Di-2-butyl bis- Dorf Ketal titanate OT acetylacetonatotitanate Al(2-OBu).sub.3 — Aluminum tri-sec-butoxide Sigma Aldrich MEK Solvent L2 Methyl ethyl ketone Sigma Aldrich IPDI Isocyanate I Isophorone diisocyanate Evonik Butoxyl Solvent L1 3-Methoxy-n-butyl acetate Celanese TIB 223 Catalyst K Dioctyltin diketanoate TIB Chemicals

(9) Production of the Silane-Terminated Polyurethane Polymers STP

(10) For each silane-terminated polyurethane polymer STP a solution of the polyol from table 1 (50% by weight in butoxyl) was mixed with a solution of IPDI (50% by weight in butoxyl) and stirred well. 0.1% by weight of TIB 223 (catalyst K) was then added and stirred until commencement of the exothermic reaction. The reaction mixture was then allowed to react for a further 24 h at 50° C. After cooling to room temperature after termination of the reaction the mixture was admixed with a calculated amount of the silane endcapper (organosilane OS1) Silquest A1170, the amount of which corresponded precisely to the amount of free NCO groups in the polyurethane polymer formed. Details of these silane-terminated polyurethane polymers STP produced are reported in table 3. The column “NCO:OH” specifies the employed molar ratio of NCO groups to OH groups before the reaction with Silquest A1170 and the column “% by wt. NCO” specifies the proportion of free NCO groups after the reaction of polyol and IPDI but before the reaction with Silquest A1170. The amount of Silquest A1170 was specified using this latter value.

(11) TABLE-US-00003 TABLE 3 Details of the polymers STP produced. Noninventive entries are marked “Ref.”. Iso- Polymer STP cyanate Polyol NCO:OH* % by wt. NCO STP01 (Ref.) IPDI Desmophen C1200 1.9 3.0 STP02 IPDI Kuraray C590 1.9 8.2 STP03 (Ref.) IPDI Oxymer M112 1.9 5.2 STP04 IPDI Desmophen C1100 1.9 5.3 STP05 (Ref.) IPDI Dynacoll 7131 1.98 2.05 STP06 (Ref.) IPDI Baycoll AS 2060 2.21 4.2 STP07 (Ref.) IPDI Baycoll AS 2060 2 3.5 STP08 IPDI Capa 3031 2 12.9 STP09 IPDI Capa 4101 2.5 11.66 STP10 IPDI Capa 4101 2.02 8.8 STP11 IPDI Baycoll 670 2 5.55 STP12 (Ref.) IPDI Baycoll AV 2113 2 6.66 *calculated values.

(12) Formulation of the Adhesion Promoter Compositions

(13) A binder composition was initially produced from each of the produced polymers STP01 to STP13 by diluting the polymer with MEK to afford a 20% solution (20% by weight of polymer). Further additives such as organosilane OS2 were then added depending on the experiment. Each resulting composition was diluted with MEK such as to afford a solution having a solids content of 20% by weight. The solids content here describes the sum of all nonvolatile substances. Details of the thus produced adhesion promoter compositions are reported in table 4. All reported numerical amounts for the additives are in % by weight based on the total composition.

(14) TABLE-US-00004 TABLE 4 Adhesion promoter compositions produced. The compositions designated “Inv” are inventive while those designated “Ref” are noninventive. Additives Exam- Polymer Silquest Silquest Silquest A- Tyzor Al(2- ple STP A1170 A189 Link 597 IBAY OBu).sub.3 Ref-01 STP01 — — — 2 — Ref-02 STP02 — — — — — Inv-01 STP02 — — — 2 — Inv-02 STP02 4 — — 4 — Inv-03 STP02 2 — — 2 2 Ref-03 STP02 — — — — 2 Ref-04 STP03 — — — 2 — Ref-05 STP03 — 2 — 2 — Ref-06 STP04 — — — — — Inv-04 STP04 — 2 2 2 — Ref-07 STP05 — — — 2 — Ref-08 STP05 2 — — 2 — Ref-09 STP06 — — — 2 — Ref-10 STP07 4 — — — — Ref-11 STP07 4 — — 4 — Ref-12 STP08 — — — — — Inv-05 STP08 2 — — 2 — Ref-13 STP09 — — — — — Inv-06 STP09 — 2 — 2 — Inv-07 STP10 4 — — 4 — Ref-14 STP11 — — — — — Inv-08 STP11 — — — 2 — Inv-09 STP11 2 — — — — Inv-10 STP11 2 — — 2 — Ref-15 STP12 4 — — — — Ref-16 STP12 2 — — 2 —

(15) The adhesion promoter compositions in table 4 were placed into tightly sealable glass bottles and after one day of storage at room temperature used for the adhesion tests. The substrate used was float glass (Rocholl, Germany) and both the air side and the tin side were used for adhesive bonding.

(16) Open Time Test

(17) The open time was tested on a selected inventive adhesion promoter composition. For accelerated testing the substrates with applied adhesion promoter were stored under cataplasma conditions (70° C., 100% relative atmospheric humidity) and subsequently adhesively bonded according to the method described above. The results are reported table 56.

(18) TABLE-US-00005 TABLE 5 Adhesive bonding on float glass (air side) immediately and after cataplasma storage. Example Immediately 7 d CL 14 d CL Inv-04 100 100 100

(19) Adhesion Test of Adhesion Promoter Compositions

(20) The compositions were then applied to an air side and a tin side of a float glass substrate using a cellulose cloth (Tela®, Tela-Kimberly Switzerland GmbH) impregnated therewith. All substrates were cleaned immediately prior to application of the adhesion promoter composition by wiping using a cellulose cloth (Tela®) that had been soaked with an isopropanol/water mixture (2:1) and flashed off for at least 2 minutes prior to the application of the adhesion promoter composition.

(21) 5 seconds after application of the adhesion promoter composition the substrate was wiped with a dry cellulose cloth (“wipe off”). Within 10 minutes a round bead of a SikaFlex® 250 adhesive was subsequently applied using an extrusion cartridge and a nozzle. SikaFlex® 250 is a high-modulus, one-component, moisture-curable polyurethane adhesive which contains polyurethane prepolymers having isocyanate groups but no adhesion promoters and is commercially available from Sika Schweiz AG.

(22) The adhesive was tested after a curing time of 7 days in a conditioning chamber (‘KL’) (23° C., 50% rel. atmospheric humidity) and after subsequent water storage (‘WL’) in water at 23° C. over 7 days and after subsequent cataplasma storage (‘CL’) of 7 days at 70° C. and 100% relative atmospheric humidity and (in selected examples) after a subsequent heat storage (‘HL’) of 24 hours at 120° C. in an oven.

(23) The adhesion of the adhesive was tested using the ‘bead adhesion test’. This involves cutting into the bead at its end just above the adhesive bonding surface. The cut end of the bead is held with round-nose pliers and pulled away from the substrate. This is done by carefully rolling up the bead onto the tip of the pliers, and making a cut at right angles to the bead pulling direction down to the bare substrate. The bead pulling speed should be chosen such that a cut has to be made about every 3 seconds. The test distance must correspond to at least 8 cm. What is assessed is the adhesive remaining on the substrate after the bead has been pulled away (cohesion failure). The adhesion properties are assessed by visual determination of the cohesive proportion of the bonding area.

(24) The higher the proportion of cohesive failure the better the adhesive bonding. Test results with cohesion failures of less than 50%, in particular less than 30%, are typically considered inadequate.

(25) The results are shown in table 6.

(26) The results from table 6 show clearly that the adhesion promoters according to the invention achieve markedly better adhesion results on float glass under all tested conditions.

(27) TABLE-US-00006 TABLE 6 Test results of adhesive bonding on float glass (air side and tin side). The compositions designated “Inv” are inventive while those designated “Ref” are noninventive. “n/b” means that the measurement was not carried out. All inventive compositions produced showed exceptional storage stability. Even after several months no precipitation or cloudiness was observable. Air side Tin side Example KL WL CL HL KL WL CL HL Ref-01 100 100 25 n/b 5 5 0 n/b Ref-02 0 25 50 n/b 0 0 50 n/b Inv-01 100 100 100 100 100 50 100 n/b Inv-02 100 100 100 100 100 75 100 n/b Inv-03 100 100 100 100 100 100 100 n/b Ref-03 100 100 100 100 0 75 100 n/b Ref-04 0 0 0 n/b 0 0 0 n/b Ref-05 0 0 0 n/b 0 0 0 n/b Ref-06 100 100 0 n/b 0 0 0 n/b Inv-04 100 100 95 n/b 50 50 100 n/b Ref-07 100 100 0 n/b 100 0 100 n/b Ref-08 100 100 0 n/b 100 0 100 n/b Ref-09 100 100 0 n/b 0 0 100 n/b Ref-10 0 0 0 n/b 0 20 10 n/b Ref-11 100 0 0 n/b 100 100 100 n/b Ref-12 100 100 100 n/b 100 0 0 n/b Inv-05 100 100 100 n/b 100 50 100 n/b Ref-13 100 100 100 n/b 20 0 20 n/b Inv-06 100 95 75 n/b 95 50 75 n/b Inv-07 100 100 100 n/b 100 50 100 n/b Ref-14 100 100 100  25 25 0 100 50 Inv-08 100 100 100 100 100 50 100 100 Inv-09 100 100 100  50 100 90 100 50 Inv-10 100 100 100 100 100 100 100 100 Ref-15 100 100 100 n/b 0 0 95 n/b Ref-16 100 100 70 n/b 100 0 100 n/b