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Method for producing oxidized lignins

A technology of lignin and kraft lignin, applied in the field of oxidized lignin, which can solve problems such as inapplicability, changing performance, and unstable products

Pending Publication Date: 2021-06-29
ROCKWOOL AS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] However, one problem associated with previously known oxidized lignins is that they are less fire resistant than underivatized lignins when used in products in which they are included in adhesive compositions, The underivatized lignin makes it unsuitable for many applications
Another problem associated with these previously known oxidized lignins is that residual alkali metal hydroxides in the products tend to destabilize the products and make them prone to alter their properties during aging

Method used

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  • Method for producing oxidized lignins
  • Method for producing oxidized lignins
  • Method for producing oxidized lignins

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0087] Example A - Oxidation of lignin with hydrogen peroxide in aqueous ammonia solution:

[0088] The amounts of ingredients used according to Example A are provided in Tables A1.1 and A1.2

[0089] During the development of the method according to the present invention, the inventors first started experiments on a laboratory scale, which were carried out on a scale of approximately 1 L.

[0090] Although kraft lignin is soluble in water at higher pH values, it is known that at a certain weight percentage the viscosity of the solution increases considerably. It is generally believed that the increase in viscosity is due to a combination of strong hydrogen bonding and π-electron interactions of the many aromatic rings present in lignin. For kraft lignin, a sudden increase in viscosity was observed at about 21-22 wt% in water, in this example 19 wt% kraft lignin was used.

[0091] In the pH adjustment step, an aqueous ammonia solution was used as a base. Its amount was fixe...

Embodiment B

[0101] Example B - Scale-up of lignin oxidation in ammonia with hydrogen peroxide to pilot scale

[0102] Oxidation of lignin with hydrogen peroxide is an exothermic process, and even at the laboratory scale, the addition of peroxide increases the temperature significantly. This is a natural problem when scaling up chemical processes, since the heat generated scales with the third power of size (volume), whereas cooling typically only increases with the square of the size (area). Additionally, due to the high viscosity of the adhesive intermediate, process equipment must be carefully selected or designed. Therefore, the amplification is carefully designed and performed in several steps.

[0103]The first scale-up step is from 1 liter (laboratory scale) to 9 liters using a professional stainless steel mixer with very efficient mechanical agitation. Scale-up resulted in only slightly higher final temperatures than those obtained at laboratory scale, which was attributed to eff...

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Abstract

The invention is directed to a method for producing oxidized lignins.

Description

[0001] field of invention [0002] The present invention relates to a process for the production of oxidized lignin, to the oxidized lignin produced by this process, and to the use of this oxidized lignin as a component of an adhesive composition, e.g. an aqueous adhesive composition for mineral fibres. . [0003] Background of the invention [0004] Lignin is a class of complex organic polymers found as the structural material of vascular plants. It makes up about 20-35% of the dry weight of wood and is therefore, besides cellulose, the most abundant polymer found in nature. Lignin is a by-product of the papermaking process, so a large amount of lignin is produced in the paper industry. Lignin separated during papermaking is usually burned as fuel. For this reason, lignin is a very cheap product, which makes it an attractive starting material. [0005] figure 1 Cross-sections of possible lignin structures are shown. [0006] Lignin thus represents an attractive feedstock...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08H7/00
CPCC08H6/00C07G1/00
Inventor D·B·约翰松I·乔汉森B·S·科尔斯加德M·尼科里克
Owner ROCKWOOL AS