LAMINATION ADHESIVE COMPOSITIONS AND THEIR APPLICATIONS

Abstract

Two part silicone lamination adhesive compositions which cure via a condensation cure chemistry using titanium and/or zirconium based catalysts at room temperature are disclosed. The compositions comprise: (i) at least one condensation curable silyl terminated polymer having at least one hydrolysable and/or hydroxyl functional group(s) per molecule; (ii) a cross-linker; and (iii) a condensation catalyst selected from the group of titanates and zirconates. Polymer (i) is not stored in the same part as cross-linker (ii) and catalyst (iii). Catalyst (iii) is present in a molar amount which is at least 50% of the moisture present cumulatively in the parts of the composition. The molar ratio of silicon bonded hydroxyl groups in polymer (i) to hydrolysable groups in cross-linker (ii) is above 0.15. The molar ratio of the silicon bonded hydroxyl groups in polymer (i) to M-OR functions is greater than 10, where M is titanium or zirconium.

Claims

1. A multiple part condensation curable lamination adhesive composition, said composition comprising: (i) at least one condensation curable silyl terminated polymer having at least one, optionally at least 2, hydrolysable and/or hydroxyl functional group(s) per molecule; (ii) a cross-linker selected from the group consisting of silanes having at least 2 hydrolysable groups, optionally at least 3 hydrolysable groups, per molecule group; and/or silyl functional molecules having at least 2 silyl groups, each silyl group containing at least one hydrolysable group; and (iii) a condensation catalyst selected from the group consisting of titanates and zirconates; wherein polymer (i) is not stored in the same part as cross-linker (ii) and catalyst (iii); wherein condensation catalyst (iii) is present in a molar amount which is at least 50% of the moisture present cumulatively in the parts of the composition; wherein the molar ratio of silicon bonded hydroxyl groups in polymer (i) to hydrolysable groups in cross-linker (ii) is above 0.15; and wherein the molar ratio of the silicon bonded hydroxyl groups in polymer (i) to condensation catalyst (iii) M-OR functions is greater than 10, where M is titanium or zirconium and R is an aliphatic hydrocarbon group.

2. The multiple part condensation curable lamination adhesive composition in accordance with claim 1, consisting of components (i), (ii) and (iii) and one or more additives selected from the group consisting of pigments, dyes, adhesion promoters, light diffusing particles, siloxane resins and/or particles with fire resistant properties.

3. The multiple part condensation curable lamination adhesive composition in accordance with claim 1, further comprising pigments and/or dyes.

4. The multiple part condensation curable lamination adhesive composition in accordance with claim 1, further comprising light diffusing particles.

5. The multiple part condensation curable lamination adhesive composition in accordance with claim 1, further comprising particles with fire resistance properties.

6. The multiple part condensation curable lamination adhesive composition in accordance with claim 1, which does not contain any inorganic filler.

7. The multiple part condensation curable lamination adhesive composition in accordance with claim 1, stored in two parts wherein said parts are divided as follows: a) polymer (i) and cross-linker (ii) in one part and polymer (i) and catalyst (iii) in the other part; or b) cross-linker (ii) in one part and polymer (i) and catalyst (iii) in the other part.

8. A method of making a laminated assembly comprising a lamination adhesive between a substrate and a superstrate, said method comprising: mixing the multiple part condensation curable lamination adhesive composition in accordance with claim 1 to form a mixed composition; applying the mixed composition onto a face of a substrate and/or superstrate; sandwiching the mixed composition between the substrate and superstrate; and laminating the same.

9. The method in accordance with claim 8, wherein a dam of polyisobutylene (PIB) rubber seal, silicone hot melt material or optically clear silicone sealant is applied to a peripheral edge of the face of the substrate and/or superstrate to which the mixed composition is to be applied to form a dam to prevent loss of the mixed composition prior to lamination.

10. The method in accordance with claim 9, wherein the dam is applied around the peripheral edge when the viscosity of the mixed composition is 30,000 mPa.Math.s at 25 C.

11. A laminated assembly comprising a cured lamination adhesive formed via the multiple part condensation curable lamination adhesive composition in accordance with claim 1, wherein the cured lamination adhesive is sandwiched between a substrate and a superstrate.

12. The laminated assembly in accordance with claim 11, wherein the substrate and/or superstrate are selected from glass, wood, concrete, stone, plastics, composites, metals or ceramics.

13. The assembly in accordance with claim 11, wherein the cured lamination adhesive is encapsulating one or more objects within the laminated assembly.

14. The assembly in accordance with claim 13, wherein the one or more objects is/are selected from electrical and/or solar power related components or decorative elements.

15. The assembly in accordance with claim 11, wherein the substrate and/or superstrate are both glass panels.

16. The assembly in accordance with claim 11, wherein a polyisobutylene (PIB) rubber seal, silicone hot melt material or optically clear silicone sealant is provided in the assembly in a peripheral gap between the substrate and superstrate adjacent to an outer edge of the cured lamination adhesive.

17. The assembly in accordance with claim 11, wherein a vapour barrier material is applied around and edge of the assembly.

18. The assembly in accordance with claim 11, wherein the assembly is cold bended to create a curved glass product.

19-21. (canceled)

Description

EXAMPLES

[0096] All viscosity measurements were made using a Brookfield cone plate viscometer RV DII with the most appropriate cone plate at 25 C. unless otherwise indicated.

[0097] Dimethyl OH terminated polydimethylsiloxane (viscosity ca 50,000 mPa.Math.s) exhibits a typical average molecular weight in number of 63,000 g/mol. Trimethoxysilyl terminated polydimethylsiloxane (viscosity ca 56,000 mPa.Math.s) exhibits a typical average molecular weight in number of 62,000 g/mol. OH terminated polydimethylsiloxane (viscosity ca 2,000 mPa.Math.s) exhibits a typical average molecular weight in number of 22,000 g/mol. Dimethyl OH terminated polydimethylsiloxane (viscosity ca 13,500 mPa.Math.s) exhibits a typical average molecular weight in number of 43,000 g/mol. Trimethoxysilyl terminated polydimethylsiloxane (viscosity ca 2,000 mPa.Math.s) exhibits a typical average molecular weight in number of 22,000 g/mol.

[0098] The compositions used in the following examples were made by mixing part A and part B together in a speedmixer. The part A and Part B were introduced into a speedmixer and were then mixed for four periods of 30 seconds at a speed of 2000 revolutions per minute (rpm). The resulting mixture was poured into an aluminum cup and onto a glass substrate surface and left to cure for 7 days at room temperature. Table 1: examples of formulations that are suitable (ex 1 to 3) for a lamination where the product is applied in stripes on the surface of each panes (high viscosity).

TABLE-US-00001 TABLE 1 Counter Counter Counter Example Example Example Example Example Example 1 2 3 1 2 3 Part A Dimethyl OH terminated 100 100 100 100 100 100 polydimethylsiloxane (viscosity ca 50,000 mPa .Math. s) Part B Trimethoxysilyl 100 100 100 100 100 100 terminated polydimethylsiloxane (viscosity ca 56,000 mPa .Math. s) tetra n-butyl titanate 0.26 0.54 0.54 0.35 0.37 0.44 Mixing ratio weight 4.8:1 3:1 2.5:1 6.5 7 8.2 (Part A:Part B) Mixed viscosity mPa .Math. s 51,000 51,000 52,000 51,000 52,000 52,000 SiOH/SiOR mol ratio 1.5 1.0 0.8 1.0 0.8 0.5 SiOH/Ti mole ratio 18.8 16.7 13.9 9.4 7.5 3.8 Bubbles n n n y y y Gel in mixer n n n n n y Adhesion to glass after CF CF AF CF CF AF 1 day cure at room temperature Adhesion to glass after CF CF CF CF CF AF 7 days cure at room temperature CF means cohesive failure, i.e. the failure occurs inside the elastomer. AF means adhesive failure, i.e. the failure occurs at the substrate/elastomer interface.

[0099] From the table 1, it can be seen that a molar ratio of SiOH/Ti mole ratio below 13.9 will lead to bubbles generated during mixing.

[0100] Similarly, if the molar ratio SiOH/SiOR is below 0.8 for high viscosity formulations the adhesion of the product onto glass is compromised.

[0101] Formulation from example 2 was used to build a 200200 glass laminate. The material was applied on both sides of the glass using a cartridge and a gun. Parallel strips were made. A hot melt silicone was used to create a dam at the periphery of the glass only on one pane. The two panes were assembled and put in a laminator. Vacuum was pulled for 7 minutes and then a pressure of 10,000 N/m.sup.2 was applied on both panes for 2 minutes. Finally, the vacuum was released and the pane was left to cure for 7 days at room temperature. The laminated glass unit is shown in FIG. 1a. No bubbles or voids are observed.

[0102] A laminated glass unit made using the same composition and processed was aged for 1000 hours at 150 C. Again, no defects or bubbles were observed after this ageing. Table 2 is showing examples that are related to more flowable formulations.

TABLE-US-00002 TABLE 2 Counter Counter Example example example 4 4 5 Part A Dimethyl OH terminated 100 100 100 polydimethylsiloxane (viscosity ca 13,500 mPa .Math. s) Part B Trimethoxysilyl 100 100 100 terminated polydimethylsiloxane (viscosity ca 2,000 mPa .Math. s) tetra n-butyl titanate 0.1 0.2 0.3 Mixing ratio weight 1:1 1:1 1:1 Mixed viscosity mPa .Math. s 5,000 5,000 5,000 SiOH/SiOR mol ratio 0.18 0.18 0.18 SiOH/Ti mole ratio 15.5 7.8 5.2 Bubbles n y y Gel in mixer n n n Adhesion to glass after CF AF AF 1 day cure at room temperature Adhesion to glass after CF BF AF 7 days cure at room temperature
From table 2 it can be seen that when the SiOH/Ti molar ratio is getting lower than acertain threshold bubbles are formed and the adhesion on glass is compromised.

[0103] Table 3 is showing examples that are related to even more flowable (lower viscosity) formulations.

TABLE-US-00003 TABLE 3 Counter Counter Example example example 5 6 7 Part A OH terminated 100 100 100 polydimethylsiloxane (viscosity ca 2,000 mPa .Math. s) Part B Trimethoxysilyl 100 100 100 terminated polydimethylsiloxane (viscosity ca 2,000 mPa .Math. s) tetra n-butyl titanate 0.1 0.2 0.3 Mixing ratio weight 0.5 0.5 0.5 Mixed viscosity mPa .Math. s 2,000 2,000 2,000 SiOH/SiOR mol ratio 0.18 0.18 0.18 SiOH/Ti mole ratio 15.5 7.8 5.2 Bubbles n n y Gel in mixer n n y Adhesion to glass after CF CF CF 1 day cure at room temperature Adhesion to glass after CF BF BF 7 days cure at room temperature

[0104] From table 3 it can be seen that when the SiOH/Ti molar ratio is getting lower than a certain threshold bubbles are formed and the adhesion on glass is compromised. Generally for the low viscosity formulation (<30,000 mPa.Math.s) a SiOH/SiOR ratio below 0.5 can still lead to acceptable laminate adhesives. However, below a ratio of 0.15, the amount of effluent is becoming high and the curing in the laminate will be diffusion limited.

[0105] From a practical perspective the compositions in Table 1 may be applied to facing sides of the substrate and superstrate before assembly, but formulations from table 2 and 3 due to their lower viscosity can only be applied on the upper facing side of the substrate one side of the pane prior to assembly, since flipping of one of the substrate or superstrate pane will result in the product flowing off from the upturned face.

[0106] One of these units was tested for impact with a 5 kg mass falling from 3 meters. No glass parts were ejected from the impact and after the impact, the glass parts were still holding together (FIG. 2), which emphasize the good adhesion of the lamination product with all parts of the laminate.

[0107] Laminated glass unit containing inserts such as plastics fabrics SEFAR Architecture Vision CU 140/0 and SEFAR Architecture Vision CU 260/25 were made successfully as depicted in FIG. 1b.