Heat-curable rubber compositions having plastisol-like rheological properties

Abstract

The invention relates to heat-curing reactive compositions based on natural and/or synthetic liquid elastomers containing olefinic double bonds and on vulcanizing agents, where these comprise a quantity, relative to the entire composition, of from 1 to 25% by weight, preferably from 1 to 15% by weight, of at least one liquid polyisoprene, preferably at least one cis-1,4 polyisoprene; a quantity, relative to the entire composition, of from 0.5 to 10% by weight, preferably from 0.5 to 5% by weight, of at least one functionalized liquid polybutadiene; a quantity, relative to the entire composition, of up to 40% by weight, preferably from 1 to 25% by weight, of a triglyceride fraction, the distribution of fatty acid in which comprises a proportion of at least 5% by weight, more particularly at least 60% by weight, of one or more omega-3 fatty acids and/or one or more omega-6 fatty acids; and at least one vulcanizing agent, where the proportion, relative to the entire composition, of synthetic polymers having at least one CC double bond and/or at least one CC triple bond is at least 7.5% by weight, preferably 9% by weight. These have plastisol-like rheology and therefore can be applied at room temperature by conventional spray systems. The invention also relates to use of same as sealant composition or as coating composition, and to methods for bonding components and/or sealing joints between components and/or coating components with use of the compositions.

Claims

1. A heat-curable reactive composition including natural and/or synthetic elastomers containing olefinic double bonds, comprising: (a) at least one liquid polyisoprene in an amount of 1 to 25 wt. % based on the total composition; (b) at least one functionalized liquid polybutadiene in an amount of 0.1 to 10 wt. % based on the total composition; (c) a triglyceride fraction, the fatty acid distribution of which includes at least 5 wt. % of one or more omega-3 fatty acid(s) and/or one or more omega-6 fatty acids, and the triglyceride fraction is present in an amount of 1 to 40 wt. % based on the total composition; and (d) at least one vulcanizing agent; wherein the content of synthetic polymers having at least one CC double bond and/or at least one CC triple bond is at least 7.5 wt. % based on the total composition; and wherein the heat-curable reactive composition is a liquid.

2. The composition according to claim 1, wherein the at least one liquid polyisoprene is cis-1,4-polyisoprene.

3. The composition according to claim 1, wherein the at least one liquid polyisoprene is present in an amount of 1 to 15 wt. %, based on the total composition.

4. The composition according to claim 1, wherein the at least one functionalized liquid polybutadiene is present in an amount of 0.5 to 5 wt. %, based on the total composition.

5. The composition according to claim 1, wherein the triglyceride fraction has the fatty acid distribution which includes at least 60 wt. %, of one or more omega-3 fatty acid(s) and/or one or more omega-6 fatty acids.

6. The composition according to claim 1, wherein the triglyceride fraction is present in an amount of 1 to 25 wt. %, based on the total composition.

7. The composition according to claim 1, wherein the content of synthetic polymers having at least one CC double bond and/or at least one CC triple bond is at least 9wt. %, based on the total composition.

8. The composition according to claim 1, wherein the at least one liquid polyisoprene comprises one or more liquid cis-1,4-polyisoprenes having a weight average molecular weight between 10000 and 70000.

9. The composition according to claim 1, wherein the at least one liquid polyisoprene comprises one or more liquid cis-1,4-polyisoprenes having a weight average molecular weight between 15000 and 50000.

10. The composition according to claim 1, wherein the at least one functionalized liquid polybutadiene includes 1,4- and/or 1,2-polybutdiene, wherein these polymers comprise terminal and/or statistically distributed side-chain functionalized groups, wherein the functional groups are selected from hydroxy, amino, carboxy, carboxylic acid anhydride and epoxy groups, and wherein a weight average molecular weight of these liquid rubbers is between 900 and 20000.

11. The composition according to claim 1, wherein the triglyceride fraction comprises a vegetable oil selected from sunflower oil, rapeseed oil, soy bean oil, tall oil, castor oil, camelina oil, tung oil, linseed oil, hempseed oil and mixtures thereof.

12. The composition according to claim 1, wherein the triglyceride fraction is a vegetable oil selected from tall oil, linseed oil, hempseed oil, castor oil and mixtures thereof.

13. The composition according to claim 1, wherein the at least one vulcanizing agent is selected from sulfur, peroxidic vulcanizing systems, quinones, quinone dioximes, dinitrosobenzenes and mixtures thereof.

14. The composition according to claim 1, further comprising filler, rheology auxiliary, pigment, tackifier, adhesion promoter, blowing agent, extender oil, anti-aging agent and combinations thereof.

15. The composition according to claim 1, wherein the composition: (a) is free of solid rubbers; and/or (b) has plastisol-like rheological properties.

16. Cured products of the composition according to claim 1.

17. A one-component or two-component adhesive, sealant, sealing compound or coating compound comprising the composition according to claim 1.

18. A method for joining components and/or for sealing joints between components, comprising: a) applying the composition according to claim 1 to at least a first component; b) joining the first component to a second component, optionally followed by welding, flanging, bolting and/or riveting the first and second components; and c) heating the first and second components to cure the composition, optionally with mechanical fixation of the components during the heating.

19. The method of claim 18 wherein the step of applying the composition consists of spraying or extruding the composition onto the at least first component.

20. A method for coating a component, comprising: a) spraying a composition according to claim 1 on the surface of a component; and b) heating the coated component so as to cure the composition.

Description

EXAMPLES

(1) Composition 1

(2) TABLE-US-00001 Component Amount Calcium oxide 2.00 4-methylphenol reaction product with dicyclopentadiene 0.25 and isobutylene Calcium carbonate, coated with stearate 13.77 Precipitated calcium carbonate 34.59 Sulfur 6.50 Silica 1.69 Zinc dibenzyldithiocarbamate 0.80 Zinc mercaptobenzothiaole 0.90 Hollow glass spheres 1.00 Refined linseed oil 21.50 Liquid 1,3-polybutadiene Mw approx. 2600 g/mol 10.00 Liquid polybutadiene with active carboxyl groups Mw 3.00 approx. 1700 g/mol Cis-1,4-polyisoprene Mw approx. 28000 g/mol 4.00
Composition 2

(3) TABLE-US-00002 Component Amount Calcium oxide 4.00 4-methylphenol reaction product with dicyclopentadiene 0.50 and isobutylene Calcium carbonate, coated with stearate 16.00 Precipitated calcium carbonate 24.38 Sulfur 8.00 Silica 1.00 Zinc dibenzyldithiocarbamate 1.20 Zinc mercaptobenzothiaole 0.90 Refined linseed oil 14.00 Liquid polybutadiene with active carboxyl groups Mw 0.50 approx. 1700 g/mol Cis-1,4-polyisoprene Mw approx. 28000 g/mol 12.00 Zinc oxide active 2.00 Carbon black 0.05 Castor oil 6.00 Tall oil distillate 10.00
Composition 3

(4) TABLE-US-00003 Component Amount Calcium oxide 4.00 Titanium dioxide 0.50 Calcium carbonate, coated with stearate 16.50 Precipitated calcium carbonate 31.65 Sulfur 5.00 Zinc dibenzyldithiocarbamate 2.20 Zinc mercaptobenzothiaole 0.90 Refined linseed oil 25.40 Liquid polybutadiene with active carboxyl groups Mw 5.00 approx. 1700 g/mol Cis-1,4-polyisoprene Mw approx. 54000 g/mol 4.80 Zinc oxide active 3.00 Carbon black 0.05 Stearic acid 1.00
Composition 4

(5) TABLE-US-00004 Component Amount Calcium oxide 4.00 Titanium dioxide 0.25 Calcium carbonate, coated with stearate 12.33 Precipitated calcium carbonate 27.10 Sulfur 6.00 Zinc dithiophosphate 4.00 Zinc mercaptobenzothiaole 0.60 Linseed oil 25.00 Liquid polybutadiene with active carboxyl groups Mw 2.00 approx. 1700 g/mol Cis-1,4-polyisoprene Mw approx. 15000 g/mol 10.00 Zinc oxide 0.50 Liquid 1,3-polybutadiene Mw approx. 1000 g/mol 4.80 Hollow glass spheres 3.10 Carbon black 0.12 Stearic acid 0.20

(6) Measurement Results

(7) Determining the Shore A Hardness

(8) The exemplary compositions were cured for 20 minutes at 150 C. for determining the Shore A hardness. Thereafter samples having a material thickness of 5 mm were removed and the Shore A hardness was determined at room temperature. The measured values are compiled in Table 1.

(9) Determining the Tensile Strength at Break and Elongation at Break

(10) The tensile strength at break and elongation at break were determined in accordance with DIN 53504. For this purpose, Teflon spacers having a thickness of 2 to 3 mm were used to produce the S2 shouldered test bars, and the uncured material was pressed between two plates covered with silicone release paper. After curing (20 minutes at 150), the test specimens were stamped out for the measurement in accordance with DIN 53504.

(11) TABLE-US-00005 TABLE 1 Composition 1 2 3 4 Tensile strength at break in MPa 1.45 0.87 1.22 0.65 Elongation at break in % 35.2 54.3 45.1 61.4 Shore A hardness in SKT 54.3 44.7 50.6 41.5 Stoving cycle: 20 minutes 150 C. object temperature