Preparation method and application of modified polyurethane aqueous dispersions of polyisocyanate curing agents

A polyisocyanate, water-based polyurethane technology, used in polyurea/polyurethane coatings, applications, chemical treatment of small raw hides/large raw hides/leather hides/furs, etc. Physical and chemical properties, the effect of superior water resistance

Inactive Publication Date: 2010-04-21
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because the construction problems caused by two-component packaging are avoided, this method is often used for cross-linking modification, but the selection range of raw materials for internal cross-linking modification is relatively narrow

Method used

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  • Preparation method and application of modified polyurethane aqueous dispersions of polyisocyanate curing agents
  • Preparation method and application of modified polyurethane aqueous dispersions of polyisocyanate curing agents
  • Preparation method and application of modified polyurethane aqueous dispersions of polyisocyanate curing agents

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] A polyisocyanate curing agent was used to modify the waterborne polyurethane dispersion, and its formulation components were listed in Table 1 to prepare a polyisocyanate curing agent modified waterborne polyurethane dispersion (PUD1).

[0040] Table 1

[0041]

[0042] Weigh according to the formula in Table 1. Dehydrate polyether polyols N220, N210 and BDO at a temperature of 120°C and a vacuum of 0.07Mpa for 3 hours, so that the water content is lower than 0.05%wt; under the protection of dry nitrogen, polyether polyols Add polyols N210 and N220, TDI (80 / 20 type) and hexamethylene diisocyanate trimer (N3390) into a four-neck flask equipped with a thermometer, stirring and reflux device, heat to 60°C while stirring, and drop 0.3g Catalyst (dibutyltin laurate) and react for 2 hours, then add BDO dropwise, add DMPA after keeping warm for 30 minutes, react at 70°C until the weight percentage of NCO groups in the system is below 5.0%, and generate about 116g of polyure...

Embodiment 2

[0044] Using the polyisocyanate curing agent prepared in Example 1 to modify the aqueous polyurethane dispersion, prepare the wood coating formulation as shown in Table 2.

[0045] Table 2 Waterborne Polyurethane Wood Coating Formulation

[0046] serial number

[0047] The preparation method is as follows: firstly add raw materials No. 2-7 into the stirring tank, disperse with a high-speed disperser for 10-30 minutes, then slowly add the PUD emulsion into the stirring tank, stir at a medium speed for 30-60 minutes, use AMP-95 Adjust the pH value of the coating. When the pH is > 7.0, slowly add No. 9 raw material, stir at a medium speed for 10 minutes, measure the viscosity of the coating system, filter, discharge and pack after the viscosity is qualified. Properties of the prepared wood coating: Appearance: Milky white slightly transparent liquid without mechanical impurities; PH=7-9; solid content 30-32%, viscosity 30-200cps. Wood coating film performance: Pencil h...

Embodiment 3

[0049] Polyethylene adipate and aliphatic diisocyanate were reacted to prepare polyisocyanate curing agent modified water-based polyurethane dispersion (PUD2). The raw material formulations used are listed in Table 3. m n is the number average molecular weight.

[0050] table 3

[0051]

[0052]

[0053] Weigh the polyethylene adipate, polycaprolactone diol and BDO at a temperature of 120°C and a vacuum of 0.09Mpa for 4 hours to dehydrate the polyethylene adipate, polycaprolactone diol and BDO according to the formula in Table 3, so that the water content is all lower than 0.05%wt;

[0054] Under the protection of dry nitrogen, polyethylene adipate and polycaprolactone diol, IPDI and IPDI trimer were added to a four-necked flask equipped with a thermometer, stirring and reflux devices, and heated to At 90°C, add 0.2g of catalyst (dimethylcyclohexylamine) dropwise and react for 2h, then add BDO dropwise, add DMPA after keeping the temperature for 30min, and react at 80°...

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Abstract

The invention discloses a preparation method and application of modified polyurethane aqueous dispersions of polyisocyanate curing agents. The preparation method comprises the following steps of: carrying out prepolymerization reaction by using polyester polyol, vulcabond monomer and a polyisocyanate curing agent; reacting with a hydrophilic chain-extending agent and a micro-molecule chain-extending agent to obtain polyurethane prepolymer containing hydrophilic groups (carboxyl or sulfonic groups) and isocyanate(NCO)-terminated groups; neutralizing the polymer into salt, and then dispersing the salt into water; and preparing the modified polyurethane aqueous dispersions of the polyisocyanate curing agents by the chain extending of a polyamine chain-extending agent. The modified polyurethane aqueous dispersions of the polyisocyanate curing agents have self-crosslinking function at room temperature, and the self-crosslinking density is over 85%. Compared with non-modified polyurethane aqueous dispersions prepared under the same condition, the modified polyurethane aqueous dispersions have superior film forming property, water resistance, alcohol resistance, pollution resistance, cold resistance, dry/wet rubbing resistance and chemical solvent resistance; and coating films have especially high drying speed, high hardness increment speed and high final hardness.

Description

technical field [0001] The invention relates to the field of modification of aqueous polyurethane dispersions, in particular to a preparation method and application of polyisocyanate curing agent-modified aqueous polyurethane dispersions. technical background [0002] Polyurethane aqueous dispersion (PUD) has the characteristics of environmental friendliness and excellent performance, and has been widely used in the fields of leather finishing agents, inks, adhesives and coatings. Traditional PUD is a linear thermoplastic polymer, and the water resistance, solvent resistance and stain resistance of the coating film are not ideal. The introduction of cross-linkable or branched groups on the polyurethane molecular chain can obtain cross-linked modified PUD, which can improve the physical and chemical properties of PUD coating film, which has become a research hotspot. At present, on the one hand, cross-linking modification is to introduce cross-linking reactive groups such as...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G18/79C08G18/12C08J3/03C09D175/04C14C11/00
Inventor 瞿金清李韶茂黄洪陈焕钦
Owner SOUTH CHINA UNIV OF TECH
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