Preparation method for low-formaldehyde melamine resin retanning agent

A technology of formaldehyde melamine and methylol melamine, which is applied in the field of preparation of synthetic resin for leather treatment, can solve the problems of high free formaldehyde content in leather, reduce free formaldehyde content in leather, etc., achieve low free formaldehyde content, good selection filling The effect of reasonable property and molecular weight

Active Publication Date: 2015-05-13
SHANGHAI GOLD LION CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The present invention aims to solve the problem that the melamine resin in the above-mentioned prior art is not suitable for the field of leather production, so that the content of free formaldehyde in the prepared leather is too high, and provides a method for preparing a low-formaldehyde melamine resin retanning agent, so that the preparation The produced melamine resin is suitable for the retanning process in leather production and reduces the content of free formaldehyde in the produced leather

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] A preparation method for a low-formaldehyde melamine resin retanning agent, comprising the following processing steps:

[0033] A. Preparation of end-capping modified monomer

[0034] Select a phenolic monomer with a functionality of 1-6, and modify it with formaldehyde and a sulfonating agent to obtain a capped modified monomer. The reaction temperature is 60°C, the reaction time is 1 hour, and the pH value is controlled at 7;

[0035] B, the synthesis of methylol melamine

[0036] Preparation of methylol melamine by reacting formaldehyde and melamine;

[0037]C. End-capping condensation of modified monomers and methylol melamine

[0038] The end-blocking modified monomer obtained in step A is mixed with the aqueous solution of methylol melamine, and the end-blocking polycondensation reaction is carried out to obtain a modified melamine resin solution. The reaction between the methylol functional group and the end-blocking modified monomer functional group The molar...

Embodiment 2

[0042] A preparation method for a low-formaldehyde melamine resin retanning agent, comprising the following processing steps:

[0043] A. Preparation of end-capping modified monomer

[0044] Select phenolic monomers with a functionality of 1-6, and modify them with formaldehyde and sulfonating agents to obtain end-capped modified monomers. The reaction temperature is 100°C, the reaction time is 6 hours, and the pH value is controlled to 14;

[0045] B, the synthesis of methylol melamine

[0046] Preparation of methylol melamine by reacting formaldehyde and melamine;

[0047] C. End-capping condensation of modified monomers and methylol melamine

[0048] The end-blocking modified monomer obtained in step A is mixed with the aqueous solution of methylol melamine, and the end-blocking polycondensation reaction is carried out to obtain a modified melamine resin solution. The reaction between the methylol functional group and the end-blocking modified monomer functional group Th...

Embodiment 3

[0052] A preparation method for a low-formaldehyde melamine resin retanning agent, comprising the following processing steps:

[0053] A. Preparation of end-capping modified monomer

[0054] Select phenolic monomers with a functionality of 1-6, and modify them with formaldehyde and sulfonating agents to obtain end-capped modified monomers. The reaction temperature is 80°C, the reaction time is 3.5 hours, and the pH value is controlled to 10.5;

[0055] B, the synthesis of methylol melamine

[0056] Preparation of methylol melamine by reacting formaldehyde and melamine;

[0057] C. End-capping condensation of modified monomers and methylol melamine

[0058] The end-blocking modified monomer obtained in step A is mixed with the aqueous solution of methylol melamine, and the end-blocking polycondensation reaction is carried out to obtain a modified melamine resin solution. The reaction between the methylol functional group and the end-blocking modified monomer functional group ...

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Abstract

The invention relates to a preparation method for a low-formaldehyde melamine resin retanning agent. The method comprises the following steps: preparation of a terminated modified monomer from a phenolic monomer with functionality of 1 to 6; synthesis of (hydroxymethyl)melamine; termination condensation of the terminated modified monomer and (hydroxymethyl)melamine; and preparation of the retanning agent. The retanning agent prepared in the invention has reasonable melamine resin molecular weight and extremely low free formaldehyde content and is applicable to leather production; and the content of free formaldehyde in produced leather reaches the standard, and the free formaldehyde content is lower than 75 ppm, reaching European standards Class B.

Description

technical field [0001] The invention relates to a method for preparing a synthetic resin for leather treatment, more specifically, the invention relates to a method for preparing a low-formaldehyde melamine resin retanning agent. Background technique [0002] Melamine resin (melamine formaldehyde resin), also known as melamine resin, is a synthetic resin widely used in various fields. It is collectively called amino resin together with dicyandiamide formaldehyde resin and urea formaldehyde resin. This type of resin is widely used in the retanning and filling process in the field of leather chemical industry, which can solve a series of problems such as insufficient fullness of leather, poor elasticity, and loose surface of leather. [0003] The synthesis process of traditional melamine resin is mainly divided into two steps: 1. The reaction of melamine and formaldehyde produces methylol melamine; 2. The condensation reaction of methylol melamine under certain conditions prod...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G14/12C14C3/22
Inventor 施闽范捷
Owner SHANGHAI GOLD LION CHEM CO LTD
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