Film with moderate crosslinking

Abstract

A polymer composition with a polymer of ethylene with a comonomer with silane group(s) containing units and an additive that is an organic compound with at least one amine moiety that has a gel content less than 10 wt % after 7 days at ambient conditions and a gel content of at least 15 wt % gel content after 14 days at 100° C. The film can be used in a laminate.

Claims

1. A process for making a laminate comprising the steps of: providing a polymer composition comprising a polymer of ethylene (a) with a comonomer with silane group(s) containing units that are hydrolysable and at least one additive (b), wherein the additive is an organic compound which comprises at least one amine moiety; extruding a film that has gel content less than 10 wt % after 7 days at 23° C. and 50% room humidity, when measured according to ASTM D2765-90; laminating the film without any peroxide decomposition with a glass layer; and condensating the silane group(s) of the polymer of ethylene (a) after lamination using the at least one additive (b), wherein the additive is an organic compound which comprises at least one amine moiety so that the laminate has a gel content of at least 15 wt % after 14 days at 100° C., when measured according to ASTM D2765-90.

2. The process according to claim 1, wherein the additive (b) comprising at least one amine moiety is added to the polymer composition during film extrusion.

3. The process according to claim 1, wherein the film is laminated at a temperature of 100° C. to 180° C.

4. The process according to claim 1, wherein the polymer of ethylene (a) with a comonomer with silane group(s) containing units that are hydrolysable is in an amount of at least 80 wt % of the polymer composition.

5. The process according to claim 1, wherein the polymer of ethylene (a) with a comonomer with silane group(s) containing units that are hydrolysable has a density of at least 900 kg/m.sup.3 and an MFR.sub.2 of 0.1 to 50 g/10 min measured with ISO 1330 at 190° C. and a load of 2.16 kg.

6. The process according to claim 1, wherein the polymer of ethylene (a) with a comonomer with silane group(s) containing units that are hydrolysable is a low density polyethylene.

7. The process according to claim 1, wherein the polymer of ethylene (a) with a comonomer with silane group(s) containing units that are hydrolysable further comprises polar comonomers (c), excluding comonomers with silane group(s) containing units that are hydrolysable.

8. The process according to claim 7, wherein the polymer of ethylene (a) with a comonomer with silane group(s) containing units that are hydrolysable further comprises a total amount of polar comonomers (c), excluding comonomers with silane group(s) containing units that are hydrolysable is from 10 wt % to 30 wt %.

9. The process according to claim 8, wherein the polar comonomers (c), excluding silane group(s) containing units, is selected from vinyl acetate (VA), butyl acrylate (BA), methyl acrylate (MA), methyl methacrylate (MMA) and ethyl acrylate (EA).

10. The process according to claim 1, wherein the total amount of silane monomer in the polymer of ethylene (a) with a comonomer with silane group(s) containing units that are hydrolysable is from 0.1 wt % to 15 wt %.

11. The process according to claim 1, wherein the additive (b) comprising at least one amine moiety is a stabiliser.

12. The process according to claim 11, wherein the additive (b) comprising at least one amine moiety includes at least one UV agent.

13. The process according to claim 11, wherein the additive (b) comprising at least one amine moiety includes at least one UV stabilizer.

14. The process according to claim 11, wherein the at least one additive (b) comprising at least one amine moiety comprises an UV stabiliser and an antioxidant and is present in the polymer composition in an amount of 0.1 wt % to 5 wt %.

15. The process according to claim 11, wherein the additive (b) comprising at least one amine moiety is a secondary amine.

16. The process according to claim 1, wherein the polymer composition is free of peroxides, dibutyl tin dilaurate (DBTDL), dioctyl tin dilaurate (DOTDL) and compounds with sulphonic acid groups.

17. A laminate of a glass layer with at least one layer that is made of a polymer composition according to the process of claim 1 comprising: (a) a polyethylene bearing hydrolysable silane group(s), and (b) at least one additive, wherein the additive is an organic compound which comprises at least one amine moiety; and wherein the at least one layer that is made of the polymer composition polymer composition has creep less than <10 mm at 100° C., 24 h, with a precondition of the creep sample of 7 days 70° C., RH95%.

18. A laminate according to claim 17, wherein the layer made of the polymer composition is free from peroxides and tin.

Description

EXAMPLES

(1) Materials

(2) EVS (2.1%) MA (26%) Terpolymer produced by a high pressure tubular reactor in a conventional manner using conventional peroxide initiator, with a max temperature of 285° C., where ethylene monomers were reacted with vinyl trimethoxysilane (VTMS) and methylacrylate (MA) co-monomers amounts so as to yield 2.1 wt % vinyl trimethoxy silane content and 26 wt % MA content in the terpolymer. CTA was used to regulate MFR as well known for a skilled person. The melt flow rate (MFR2@190° C.) according to ISO 1133 (190° C., 2.16 kg) is 20 g/10 min and a melting point of 85° C.

(3) ##STR00001##

(4) Compounding of the Blends

(5) The different compounds were compounded on a pilot scale extruder (Prism TSE 24TC). The obtained mixture was melt mixed in conditions given in the table below and extruded to a string and pelletized.

(6) TABLE-US-00001 TABLE 1 Extruder setting for produced materials. Set Values Temperatures (° C.) Extruder Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 rpm output pressure 120° C. 140° C. 140° C. 140° C. 135° C. 130° C. 222 7.7 kg/h 55 bar

(7) Film Sample Preparation

(8) Films (tapes) with a dimension of 50 mm width and 0.45 mm thickness were extruded on a Collin teach-line E 20T extruder. The tapes were produced with the following set temperatures:

(9) 150/150/150° C. and 50 rpm.

(10) Results

(11) TABLE-US-00002 TABLE 2 Results from creep test. Test was performed at directly at 100° C. Amounts of additives are given in weight percentages. AO is 0.1 wt % Irgafos 168 and 0.5 wt % of Irganox 1076. All are wt % Comp 1 Comp 2 Comp 3 Inv 1 Inv 2 Inv 3 Inv 4 Inv 5 Inv 6 EVS (2.1%) MA (26%) 100 99.4 99.4 98.9 98.9 99.2 98.9 99.2 98.9 AO 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 Chimassorb 944 0.5 0.25 0.1 0.25 0.2 Tinuvin 622 0.25 0.1 Tinuvin 770 0.25 0.5 Creep 100° C., 24 h Fail 67 mm 12 mm 21 mm 38 mm 12 mm

(12) Table 2 shows results from creep testing of EVS (2.1%) MA (26%). The different samples have different UV-stabiliser and concentrations. The results after 24 h at 100° C. shows that the creep performance above the terpolymer melting point is improved by the addition of an amine moiety as a base catalyst for silane crosslinking even though the creep specimens have not been subjected to any preconditioning, meaning gel content is <1 wt %.

(13) Creep specimens with films of Inventive Example 1 were prepared and subjected to preconditioning at 70° C., 95% RH. The results from creep measurements in Table 3 show the effect of amine moiety catalysed crosslinking on the creep resistance over the polymer melting temperature.

(14) TABLE-US-00003 TABLE 3 The influence of preconditioning at 70° C., 95% RH on the creep resistance for Inventive Example 1. Days at 70° C., 95% RH Creep at 100° C., 24 h 0 12 mm 4 0 mm 7 0 mm 14 0 mm

(15) TABLE-US-00004 TABLE 4 Results from gel-content measurements as a function of temperature. Gel % Gel % Gel % Gel % 0 days 2 days 7 days 14 days Comparative Example 3 Ambient <1 <1 <1 <1  50° C. <1 <1 <1 <1 100° C. <1 <1 <1 4 Inventive Example 5 Ambient <1 <1 <1 <1  50° C. <1 <1 <1 <1 100° C. <1 <1 19 39 Inventive Example 1 Ambient <1 <1 <1 <1  50° C. <1 <1 <1 <1 100° C. <1 9 43 51 Inventive Example 6 Ambient <1 <1 <1 <1  50° C. <1 <1 <1 <1 100° C. <1 <1 <1 36

(16) From the results on gel-content measurements in Table 4 it is seen that the addition of an amine moiety will catalyse crosslinking. Especially the gel-content after 14 days at 100° C. is significantly improved. This will improve the creep resistance above the polymer melting temperature. At 50° C. there is a low crosslinking activity even after 14 days. A low gel content is needed to maintain good adhesion to various substrates.

CONCLUSION

(17) By adding an amine moiety to a polymer of ethylene (a) with a comonomer with silane group(s) containing units that are hydrolysable, crosslinking takes place at elevated temperatures. This will improve the creep resistance of the polymer of ethylene (a) with a comonomer with silane group(s) containing units that are hydrolysable over the melting point.