Method for testing the in situ silanization of bright fillers

Patent metadata

Field	Value
Publication number	US-10988602-B2
Application number	US-201716072620-A
Country	US
Kind code	B2
Filing date	Jan 19, 2017
Priority date	Jan 25, 2016
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

Abstract

The invention relates to a method of testing silanization, which permits inline control of the in situ silanization of light-colored fillers, especially precipitated silicas. This enables continuous in situ silanization in the production of rubber mixtures comprising silanized light-colored fillers, and representative control of the rubber mixture under production conditions. The process is additionally nondestructive and has a high tolerance for carbon black as an additional constituent of the rubber mixture.

First claim

What is claimed is:

1. A method of in-situ testing of the silanization of light-colored fillers in rubbers, the method comprising:
extruding a mixture comprising at least one silanized light-colored filler and at least one rubber to form an extrudate,
subjecting the extrudate to ultrasound waves within a frequency range from 4 to 10 MHz, and
measuring the signal intensity of the ultrasound waves after transmission of the ultrasound waves through the extrudate, wherein the measured intensity relates directly to an amount of silanization.

2. The method as claimed in claim 1 , further comprising determining the relative attenuation coefficient α rel of the extrudate in the frequency range of the ultrasound waves, wherein the relative attenuation coefficient relates inversely to an amount of silanization.

3. The method as claimed in claim 2 , further comprising:
determining the standard deviation of the relative attenuation coefficient α rel , and
using the standard deviation to monitor the dispersion of the light-colored filler in the extrudate.

4. The method as claimed in claim 2 , wherein:
the light-colored filler is selected from mica, kaolins, chalks, calcium carbonates, talc, zinc oxides, aluminum oxides, titanium dioxides, silica and silicates;
the ultrasound waves are produced by an emitter and detected at a receiver and the distance between the emitter and the receiver is more than 5 mm to 25 mm, and
the rubber mixture comprises 50 to 250 phr of the light-colored filler.

5. The method as claimed in claim 4 , wherein:
the ultrasound waves have a frequency of 5 to 7 MHz;
the distance between the emitter and the receiver is 10 mm to 25 mm, and
the rubber mixture comprises 60 to 150 phr of the light-colored filler.

6. The method as claimed in claim 5 , wherein:
the distance between the emitter and the receiver is 15 to 20 nm; and
the rubber mixture comprises 70 to 100 phr of the light-colored filler,
the silanized filler is formed in the extruder from at least one light-colored filler and at least one silanizing agent at a silanization temperature of 140 to 160° C.
the light-colored filler comprises silica; and
the method further comprises monitoring the dispersion of the light-colored filler in the extrudate by at least one of:
determining the coefficient of variation of the logarithm of the ultrasound wave intensity or of the ultrasound wave amplitude ln A, and using the coefficient of variation to monitor the dispersion of the light-colored filler in the extrudate; and
determining the standard deviation of the relative attenuation coefficient α rel , and using the standard deviation to monitor the dispersion of the light-colored filler in the extrudate.

7. The method as claimed in claim 1 , further comprising:
determining the coefficient of variation of the logarithm of the ultrasound wave intensity or of the ultrasound wave amplitude ln A, and
using the coefficient of variation to monitor the dispersion of the light-colored filler in the extrudate.

8. The method as claimed in claim 1 , wherein the ultrasound waves are produced by an emitter and detected at a receiver and the distance between the emitter and the receiver is more than 5 mm to 25 mm.

9. The method as claimed in claim 1 , wherein:
the rubber mixture comprises 50 to 250 phr of the light-colored filler; and
the light-colored filler comprises mineral natural and synthetic fillers that are not based on carbon black.

10. The method as claimed in claim 1 , wherein the silanized filler is formed in the extruder from at least one light-colored filler and at least one silanizing agent.

11. A method of producing rubber mixtures comprising silanized light-colored fillers, the method comprising:
mixing at least one light-colored filler with at least one rubber and at least one silanizing agent, and
silanized the light-colored filler, and
testing at least a portion of the rubber mixture by the method as claimed in claim 1 .

12. The method as claimed in claim 11 , wherein the silanization is effected at a temperature of 140 to 160° C.

13. The method as claimed in claim 11 , wherein the process is conducted continuously or as a batchwise process, preferably continuously.

14. The method as claimed in claim 11 , wherein the silanizing agent comprises a silane, preferably bis(3-triethoxysilypropyl) tetrasulfide.

15. The method of producing rubber mixtures according to claim 11 , wherein more than 10% by volume of the rubber mixture is tested.

16. The method of producing rubber mixtures according to claim 11 , wherein 100% by volume of the rubber mixture is tested.

17. A method of producing crosslinkable rubber mixtures comprising silanized light-colored filler, the method comprising producing the rubber mixtures according to the method as claimed in claim 11 , and adding one or more crosslinking agents before, during, and/or after the production of the rubber mixture.

18. A method of producing vulcanizates comprising the crosslinkable rubber mixtures produced in accordance with the method as claimed in claim 17 , the method comprising vulcanizing the crosslinkable rubber mixture at a temperature of 100° C. to 200° C.

19. The use of measurement devices for determining the sound wave amplitude and/or sound wave intensity at a frequency of the ultrasound waves within a range from 4 to 10 MHz, for a method as claimed in claim 1 .

20. The use of measurement devices as claimed in claim 19 , wherein the attenuation coefficient is determined in the region of the frequency of the ultrasound waves.

Assignees

• Lanxess Deutschland Gmbh

Inventors

• Schroeder Andreas
• Wawrzinski Lars
• Graeff Ludwig
• Schilling Juergen

Classifications

• C08K3/36 Primary

  Silica · CPC title

• C09C3/00

  Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties · CPC title

• C08K9/06

  with silicon-containing compounds · CPC title

• C08L9/06

  Copolymers with styrene · CPC title

• G01N29/348

  with frequency characteristics, e.g. single frequency signals, chirp signals (measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00) · CPC title