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Multi-aldehyde-group amphoteric polyurethane retanning agent and preparation method thereof

A technology of polyurethane and retanning agent is applied in the field of retanning agent, which can solve the problems of influence, lack of fullness and discoloration of the leather, and achieve the effects of improving the stability of heat and humidity resistance, improving the reactivity, and improving the filling effect.

Inactive Publication Date: 2018-06-22
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Traditional retanning agents are mainly acrylic anionic polymer retanning agents. This type of retanning agent has the advantages of making leather thicker, softer, finer grained, and resistant to sweat and light. The problem of discoloration is overcome. The main cause of discoloration is that the surface of wet blue leather after chrome tanning is positively charged. When combined with anionic retanning agent, it reduces the binding point of anionic dyes and skin collagen during dyeing, thus affecting the dyeing. The dyeing rate will make the leather tone after dyeing not full, and the phenomenon of discoloration often occurs

Method used

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  • Multi-aldehyde-group amphoteric polyurethane retanning agent and preparation method thereof
  • Multi-aldehyde-group amphoteric polyurethane retanning agent and preparation method thereof
  • Multi-aldehyde-group amphoteric polyurethane retanning agent and preparation method thereof

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preparation example Construction

[0016] The preparation method of the amphoteric aldehyde polyurethane retanning agent that the present invention relates to, in N 2 Under the protection of isophorone diisocyanate and polytetrahydrofuran under the action of a catalyst, the prepolymerization reaction is carried out, and the chain extender: 2,2-hydroxymethylpropionic acid, N-methyldiethanolamine and 2,4 - Dihydroxybenzaldehyde is added to the system to react for a certain period of time, then the temperature is lowered to neutralize and emulsify. Specifically include the following steps:

[0017] Step 1: Firstly, 0.04 mole of isophorone diisocyanate and 0.01 mole of polytetrahydrofuran were mixed in N 2 Mix evenly under the protection of the catalyst, add two drops of catalyst, react at 40~50°C for 0.3~0.5h, raise the temperature to 70°C for 1h.

[0018] Step 2: Then raise the temperature of the system to 70-80°C, add 0.0086 moles of 2,2-dimethylolpropionic acid and 0.0049 moles of N-methyldiethanolamine to th...

Embodiment 1

[0021] Step 1: Firstly, 0.04 mole of isophorone diisocyanate and 0.01 mole of polytetrahydrofuran were mixed in N 2 Under the protection of the mixture, mix evenly, add two drops of catalyst, react at 40°C for 0.5h, then raise the temperature to 70°C for 1h.

[0022] Step 2: Then raise the temperature of the system to 70° C., add 0.0086 mol of 2,2-dimethylolpropionic acid and 0.0049 mol of N-methyldiethanolamine into the system of step 1 to react for 3 h.

[0023] Step 3: Finally, add 0.0042 moles of 2,4-dihydroxybenzaldehyde into the reaction system of step 3 and keep the temperature constant for 3 hours. After cooling down to 40°C, add 0.0080 moles of triethylamine to neutralize for 0.5 hours, then add distilled water to stir and emulsify at high speed. A polyaldehyde-based amphoteric polyurethane retanning agent is obtained.

Embodiment 2

[0025] Step 1: Firstly, 0.04 mole of isophorone diisocyanate and 0.01 mole of polytetrahydrofuran were mixed in N 2 Under the protection of the mixture, mix evenly, add two drops of catalyst, react at 42°C for 0.45h, then raise the temperature to 70°C for 1h.

[0026] Step 2: Then the temperature of the system was raised to 73°C, and 0.0086 moles of 2,2-dimethylolpropionic acid and 0.0049 moles of N-methyldiethanolamine were reacted for 2.8 hours.

[0027] Step 3: Finally, add 0.0063 moles of 2,4-dihydroxybenzaldehyde to the reaction system of step 3 and keep the temperature constant for 2.8 hours. After cooling down to 40°C, add 0.0086 moles of triethylamine for neutralization for 0.5 hours, then add distilled water High-speed agitation and emulsification to obtain polyaldehyde-based amphoteric polyurethane retanning agent.

[0028] Embodiment 2 is carried out the detection of infrared and ultraviolet, figure 2 It is the infrared spectrogram of Example 2, the absorption pe...

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Abstract

The invention discloses a multi-aldehyde-group amphoteric polyurethane retanning agent and a preparation method thereof. The preparation method comprises the following steps: under the protection of N2, carrying out pre-polymerization reaction on isophorone diisocyanate and polytetrahydrofuran under the action of a catalyst; after raising the temperature, adding chain extenders including 2,2-dimethylol propionic acid, N-methyldiethanolamine and 2,4-dihydroxy benzaldehyde into a system respectively; after reacting for a period of time, cooling and carrying out neutralization and emulsification;finally, obtaining the multi-aldehyde-group amphoteric polyurethane retanning agent. The multi-aldehyde-group amphoteric polyurethane retanning agent provided by the invention contains cation groups,carboxyl and aldehyde groups and can be used for effectively improving the reaction performance with a tanned leather blank and improving the retanning on hydrothermal stability of leather.

Description

technical field [0001] The invention relates to the technical field of retanning agents, in particular to a polyaldehyde-based amphoteric polyurethane retanning agent and a preparation method thereof. Background technique [0002] Retanning is a crucial process in leather making, commonly known as "golden touch". The retanned leather has good physical properties, such as fullness, grain compactness, dyeing uniformity, etc. Therefore, the leather industry has always been Committed to the research of retanning agent. There are many types of retanning agents, ranging from inorganic tanning agents with small molecular weight to vegetable tanning agents with large molecular weight, tannins and synthetic tanning agents, etc. Different tanning agents meet different performances. Traditional retanning agents are mainly acrylic anionic polymer retanning agents. This type of retanning agent has the advantages of making leather thicker, softer, finer grained, and resistant to sweat an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G18/66C08G18/48C08G18/34C08G18/32C08G18/10C14C3/22
CPCC08G18/10C08G18/3215C08G18/3275C08G18/348C08G18/4854C08G18/6659C14C3/22
Inventor 王学川柴晓叶许伟李季
Owner SHAANXI UNIV OF SCI & TECH
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