阅读说明：本技术 一种单组分聚氨酯树脂的合成革的制备方法 (Preparation method of synthetic leather of single-component polyurethane resin ) 是由 宗军业 鲁明友 于 2019-10-24 设计创作，主要内容包括：本发明涉及合成革的技术领域,公开了一种单组分聚氨酯树脂的合成革的制备方法,包括以下步骤：S1、聚氨酯预聚体的合成；在反应釜中加入多元醇混合物,加热至45-50℃搅拌3-5分钟后,再加入异氰酸酯,在氮气保护下,加热至80-85℃,反应1-2小时,得到聚氨酯预聚体；S2、成革反应；在S1的聚氨酯预聚体中加入固化剂、促进剂、平摊剂,搅拌后涂布,进入烘箱后,在130-140℃下,反应3-5min成革。本发明具有以下优点和效果：避免了传统溶剂型聚氨酯树脂由多元醇、小分子二元醇、异氰酸酯及各种助剂在DMF等有机溶剂中反应,容易导致溶剂残留造成环境污染的问题；同时不需要对现有的合成革设备进行改造,克服了双组份无溶剂树脂应用上的缺陷。(The invention relates to the technical field of synthetic leather, and discloses a preparation method of synthetic leather of single-component polyurethane resin, which comprises the following steps: s1, synthesizing a polyurethane prepolymer; adding a polyol mixture into a reaction kettle, heating to 45-50 ℃, stirring for 3-5 minutes, then adding isocyanate, heating to 80-85 ℃ under the protection of nitrogen, and reacting for 1-2 hours to obtain a polyurethane prepolymer; s2, leather forming reaction; and adding a curing agent, an accelerant and a leveling agent into the polyurethane prepolymer of S1, stirring, coating, entering an oven, and reacting at the temperature of 130-140 ℃ for 3-5min to obtain the finished leather. The invention has the following advantages and effects: the problem that the traditional solvent type polyurethane resin is easy to cause solvent residue to cause environmental pollution due to the reaction of polyhydric alcohol, micromolecule dihydric alcohol, isocyanate and various auxiliary agents in organic solvents such as DMF (dimethyl formamide) and the like is solved; meanwhile, the existing synthetic leather equipment does not need to be modified, and the defect of application of the double-component solvent-free resin is overcome.)

1. A preparation method of synthetic leather of single-component polyurethane resin is characterized by comprising the following steps: the method comprises the following steps:

s1, synthesizing a polyurethane prepolymer; adding a polyol mixture into a reaction kettle, heating to 45-50 ℃, stirring for 3-5 minutes, then adding isocyanate, heating to 80-85 ℃ under the protection of nitrogen, and reacting for 1-2 hours to obtain a polyurethane prepolymer; according to weight percentage, the polyol mixture accounts for 60-80%, and the isocyanate accounts for 20-30%;

s2, leather forming reaction; adding a curing agent, an accelerant and a leveling agent into the polyurethane prepolymer of S1, stirring, coating, entering an oven, and reacting at the temperature of 130-; according to the weight percentage, the curing agent accounts for 10-20% of the main material consisting of the polyol mixture and the isocyanate, and the accelerating agent and the spreading agent respectively account for 0.05-0.5% of the main material consisting of the polyol mixture and the isocyanate.

2. A method of preparing synthetic leather from one-component polyurethane resin according to claim 1, wherein the method comprises the following steps: the polyol mixture is polytetrahydrofuran ether glycol.

3. A method for preparing a synthetic leather of one-part polyurethane resin according to claim 1, wherein: the polyol mixture comprises, in weight percent, 40-50% polytetrahydrofuran ether glycol and 20-30% polypropylene glycol ether.

4. A method of preparing synthetic leather from one-component polyurethane resin according to claim 3, wherein: in the S1, the polyol mixture is heated to 45-50 ℃ and stirred for 3-5 minutes, and then stirred for 1-2 hours at 105-110 ℃ and below-0.095 MPa, so as to fully dehydrate.

5. A method of preparing synthetic leather from one-component polyurethane resin according to claim 1, wherein the method comprises the following steps: the isocyanate is isophorone diisocyanate or toluene diisocyanate.

6. A method of preparing synthetic leather from one-component polyurethane resin according to claim 1, wherein the method comprises the following steps: the curing agent is an amine curing agent prepared by reacting phenols with dimethylamine.

7. A method of preparing synthetic leather from one-component polyurethane resin according to claim 1, wherein the method comprises the following steps: the promoter is an organic tin catalyst.

8. A method of preparing synthetic leather from one-component polyurethane resin according to claim 1, wherein the method comprises the following steps: the spreading agent is polydimethylsiloxane.

Technical Field

The invention relates to the technical field of synthetic leather, in particular to a preparation method of synthetic leather of single-component polyurethane resin.

Background

The polyurethane industry in china has developed over the last few years on a considerable scale from basic raw materials to products and machinery. Recent data shows that china has become the largest polyurethane consumer market worldwide. Meanwhile, China is also a great polyurethane producing country and is a prime force for promoting the growth of the global polyurethane market in the future.

The basic synthesis process of solvent type polyurethane resin is that polyol, small molecular diol, isocyanate and various assistants react in organic solvent such as DMF, etc. to obtain the product with solvent content of 50-70%, and in dry process, the polyurethane resin is coated on release typeOn the paper, organic solvents such as DMF are volatilized at high temperature through an oven and are recovered, in the process, the organic solvents such as DMF are inevitably subjected to environmental pollution in the volatilization and absorption process, and a large amount of solvents are volatilized and remained, so that great damage is caused to a human body in the synthetic leather product. In the wet process, DMF and H are utilized₂0 unlimited mutual solubility, so that the solvent type PU/DMF system is caused by H₂Presence of 0, DMF and H₂0 are substituted with each other so that DMF is substituted by H₂0 is extracted out, and finally the solvent type PU forms a microporous structure, and the preparation method has two problems, one is that DMF is adopted as a solvent, and the solvent pollution of DMF is caused in the processing process; second is H₂0 can not completely replace DMF in polyurethane, which can cause DMF residue in the product and finally cause the problem of safety and environmental protection of the product.

The general solvent-free resin is also called as two-component solvent-free resin, the conventional synthetic leather equipment needs to be modified at present, a solvent-free machine head is installed, a polyol component and an isocyanate component are respectively contained in a tank body of a solvent-free two-component feeding machine, and then the two components are mixed and dispersed at the machine head at a high speed, but the investment is large, the operation precision requirement is extremely high, the product grade product rate is low, and the two-component solvent-free resin is difficult to popularize in a large area due to all the defects.

Therefore, how to avoid solvent pollution and overcome the defect of application of the double-component solvent-free resin is a problem which is urgently needed to be solved in the production of environment-friendly synthetic leather without modifying the conventional synthetic leather equipment.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a preparation method of synthetic leather of single-component polyurethane resin, which avoids the problem of solvent pollution and can overcome the defect of application of double-component solvent-free resin, namely, the conventional synthetic leather equipment is not required to be modified.

In order to achieve the purpose, the invention provides the following technical scheme:

a preparation method of synthetic leather of single-component polyurethane resin comprises the following steps:

s1, synthesizing a polyurethane prepolymer; adding a polyol mixture into a reaction kettle, heating to 45-50 ℃, stirring for 3-5 minutes, then adding isocyanate, heating to 80-85 ℃ under the protection of nitrogen, and reacting for 1-2 hours to obtain a polyurethane prepolymer; according to weight percentage, the polyol mixture accounts for 60-80%, and the isocyanate accounts for 20-30%;

s2, leather forming reaction; adding a curing agent, an accelerant and a leveling agent into the polyurethane prepolymer of S1, stirring, coating, entering an oven, and reacting at the temperature of 130-; according to the weight percentage, the curing agent accounts for 10-20% of the main material consisting of the polyol mixture and the isocyanate, and the accelerating agent and the spreading agent respectively account for 0.05-0.5% of the main material consisting of the polyol mixture and the isocyanate.

By adopting the technical scheme, after the polyurethane prepolymer with the end capped by the cyanate ester group is obtained by heating and reacting the polyol mixture and the isocyanate under the protection of nitrogen, the curing agent, the accelerant and the leveling agent are added to synthesize the leather, so that on one hand, the problem that the solvent residue is easy to cause environmental pollution because the traditional solvent type polyurethane resin is prepared by reacting the polyol, the micromolecule dihydric alcohol, the isocyanate and various auxiliaries in organic solvents such as DMF and the like is solved; on the other hand, the polyol mixture and the isocyanate are not required to be respectively contained in a tank body of the solvent-free two-component feeding machine and then are mixed by the modified solvent-free machine head, namely, the conventional synthetic leather equipment is not required to be modified, the polyurethane prepolymer can be conveniently prepared only in the reaction kettle, the operation is simple, the operation range is wide, the defect of application of the two-component solvent-free resin is overcome, the large-area popularization of the solvent-free resin is made possible, and the national environment protection trend is met.

The invention is further configured to: the polyol mixture is polytetrahydrofuran ether glycol.

By adopting the technical scheme, the requirement on the viscosity of the resin is higher in the production process of the synthetic leather, the 7000-plus 9000CPS/25 ℃ is generally required, the viscosity of the solvent-based resin can be adjusted by a solvent, the single-component solvent-free resin does not modify the conventional synthetic leather production line, the viscosity also meets the standard of 7000-plus 9000CPS/25 ℃, the general polyester polyol has higher viscosity, high normal-temperature reaction activity, poorer hydrolysis resistance and other properties, the polytetrahydrofuran ether glycol has lower viscosity, low normal-temperature reaction activity and better hydrolysis resistance, and can meet the viscosity requirement; the hydrolysis resistance stability of the synthetic leather can be improved through the polytetrahydrofuran ether glycol.

The invention is further configured to: the polyol mixture comprises, in weight percent, 40-50% polytetrahydrofuran ether glycol and 20-30% polypropylene glycol ether.

By adopting the technical scheme, the polytetrahydrofuran ether has low viscosity, low normal-temperature reaction activity and good hydrolysis resistance, but has high price, so that the added polypropylene glycol ether which can be partially synergistic with polytetrahydrofuran ether glycol without reducing the hydrolysis resistance of the synthetic leather and has low price can further reduce the production cost, the large-area popularization of the synthetic leather prepared from the single-component resin becomes possible, and the synthetic leather conforms to the national great trend of environmental protection.

The invention is further configured to: in the S1, the polyol mixture is heated to 45-50 ℃ and stirred for 3-5 minutes, and then stirred for 1-2 hours at 105-110 ℃ and below-0.095 MPa, so as to fully dehydrate.

By adopting the technical scheme, the polypropylene glycol ether is easy to absorb water, so that the polypropylene glycol ether needs to be heated under a vacuum condition before reaction to achieve the purpose of full dehydration and avoid influencing the performance of components.

The invention is further configured to: the isocyanate is isophorone diisocyanate or toluene diisocyanate.

By adopting the technical scheme, the isocyanate is added after the polyol mixture such as polytetrahydrofuran ether, polypropylene glycol ether and the like is fully dehydrated, and the isocyanate-terminated polyurethane prepolymer is prepared by reaction under the protection of nitrogen, so that the polyurethane prepolymer can be prepared without modifying the conventional synthetic leather equipment, the defect of the application of the traditional bi-component solvent-free resin is overcome, the operation is simple, and the process of the synthetic leather is easier to perform.

The invention is further configured to: the curing agent is an amine curing agent prepared by reacting phenols with dimethylamine.

By adopting the technical scheme, the single-component solvent-free prepolymer has small molecular weight, cannot meet the requirement of the physical property of the synthetic leather, needs to be added with a curing agent, improves the molecular weight of resin, and has a moderate reticular structure so as to meet the requirement of improving the physical property.

The invention is further configured to: the promoter is an organic tin catalyst.

By adopting the technical scheme, the leather-forming reaction is promoted by adopting the organic tin catalyst, and the leather-forming efficiency is improved.

The invention is further configured to: the spreading agent is polydimethylsiloxane.

By adopting the technical scheme, the leveling agent polydimethylsiloxane has excellent physical characteristics, so that the components are dispersed more uniformly, the structural strength of a system is improved, the toughness and the wear resistance of the synthetic leather can be enhanced, and the leveling agent polydimethylsiloxane has defoaming, lubricating and other performances.

In conclusion, the invention has the following beneficial effects:

1. after a polyol mixture and isocyanate are heated and reacted under the protection of nitrogen to obtain a polyurethane prepolymer, a curing agent, an accelerant and a leveling agent are added to synthesize leather, so that the problem that the traditional solvent type polyurethane resin is easily subjected to solvent residue to cause environmental pollution because the polyol, the micromolecule dihydric alcohol, the isocyanate and various auxiliaries are reacted in organic solvents such as DMF (dimethyl formamide) and the like is solved; on the other hand, the polyol mixture and the isocyanate are not required to be respectively contained in a tank body of the solvent-free two-component feeding machine and then are mixed by the modified solvent-free machine head, the conventional synthetic leather equipment is not required to be modified, the polyurethane prepolymer can be conveniently prepared only in the reaction kettle, the operation is simple, the operation range is wide, the defect of application of the two-component solvent-free resin is overcome, the large-area popularization of the solvent-free resin is made possible, and the national environment protection trend is met.

Detailed Description

The present invention will be described in further detail below.

Example 1

A preparation method of synthetic leather of single-component polyurethane resin comprises the following steps:

s1, synthesizing a polyurethane prepolymer; adding polytetrahydrofuran ether glycol and polypropylene glycol ether into a reaction kettle, heating to 45 ℃, stirring for 3 minutes, stirring for 1 hour at 105 ℃ and under-0.095 MPa, fully dehydrating, adding isocyanate, heating to 80 ℃ under the protection of nitrogen, and reacting for 1 hour to obtain a polyurethane prepolymer;

s2, leather forming reaction; adding a curing agent, an accelerant and a leveling agent into the polyurethane prepolymer obtained in the step S1, stirring, coating, putting into an oven, and reacting for 3min at 130 ℃ to obtain leather; the amine curing agent is prepared by Mannich reaction of nonyl phenol and dimethylamine, and the accelerator is dibutyltin diacetate; the compositions of the polyol mixture and the isocyanate, and the percentages of the curing agent, the accelerator and the leveling agent in the major ingredients of the polyol mixture and the isocyanate in weight percentage are shown in the following table 1-1.

Example 2

A preparation method of synthetic leather of single-component polyurethane resin comprises the following steps:

s1, synthesizing a polyurethane prepolymer; adding polytetrahydrofuran ether glycol and polypropylene glycol ether into a reaction kettle, heating to 50 ℃, stirring for 5 minutes, stirring for 2 hours at the temperature of 110 ℃ and under the pressure of-0.095 MPa, fully dehydrating, adding isocyanate, heating to 85 ℃ under the protection of nitrogen, and reacting for 2 hours to obtain a polyurethane prepolymer;

s2, leather forming reaction; adding a curing agent, an accelerant and a leveling agent into the polyurethane prepolymer of S1, stirring, coating, putting into an oven, and reacting for 5min at 140 ℃ to obtain finished leather; the amine curing agent is prepared by Mannich reaction of nonyl phenol and dimethylamine, and the accelerator is dibutyltin diacetate; the compositions of the polyol mixture and the isocyanate, and the percentages of the curing agent, the accelerator and the leveling agent in the major ingredients of the polyol mixture and the isocyanate in weight percentage are shown in the following table 1-1.

Example 3

A preparation method of synthetic leather of single-component polyurethane resin comprises the following steps:

s1, synthesizing a polyurethane prepolymer; adding polytetrahydrofuran ether glycol and polypropylene glycol ether into a reaction kettle, heating to 48 ℃, stirring for 4 minutes, stirring for 2 hours at 108 ℃ and under-0.095 MPa, fully dehydrating, adding isocyanate, heating to 83 ℃ under the protection of nitrogen, and reacting for 2 hours to obtain a polyurethane prepolymer;

s2, leather forming reaction; adding a curing agent, an accelerant and a leveling agent into the polyurethane prepolymer of S1, stirring, coating, putting into an oven, and reacting at 135 ℃ for 4min to obtain leather; the amine curing agent is prepared by Mannich reaction of nonyl phenol and dimethylamine, and the accelerator is dibutyltin diacetate; the compositions of the polyol mixture and the isocyanate, and the percentages of the curing agent, the accelerator and the leveling agent in the major ingredients of the polyol mixture and the isocyanate in weight percentage are shown in the following table 1-1.

Example 4

A preparation method of synthetic leather of single-component polyurethane resin comprises the following steps:

s1, synthesizing a polyurethane prepolymer; adding polytetrahydrofuran ether glycol and polypropylene glycol ether into a reaction kettle, heating to 45 ℃, stirring for 3 minutes, then adding isocyanate, heating to 80 ℃ under the protection of nitrogen, and reacting for 1 hour to obtain a polyurethane prepolymer;

s2, leather forming reaction; adding a curing agent, an accelerant and a leveling agent into the polyurethane prepolymer obtained in the step S1, stirring, coating, putting into an oven, and reacting for 3min at 130 ℃ to obtain leather; the amine curing agent is prepared by Mannich reaction of nonyl phenol and dimethylamine, and the accelerator is dibutyltin diacetate; the compositions of the polyol mixture and the isocyanate, and the percentages of the curing agent, the accelerator and the leveling agent in the major ingredients of the polyol mixture and the isocyanate in weight percentage are shown in the following table 1-1.

Example 5

A preparation method of synthetic leather of single-component polyurethane resin comprises the following steps:

s1, synthesizing a polyurethane prepolymer; adding polytetrahydrofuran ether glycol into a reaction kettle, heating to 45 ℃, stirring for 3 minutes, then adding isocyanate, heating to 80 ℃ under the protection of nitrogen, and reacting for 1 hour to obtain a polyurethane prepolymer;

s2, leather forming reaction; adding a curing agent, an accelerant and a leveling agent into the polyurethane prepolymer obtained in the step S1, stirring, coating, putting into an oven, and reacting for 3min at 130 ℃ to obtain leather; the amine curing agent is prepared by Mannich reaction of nonyl phenol and dimethylamine, and the accelerator is dibutyltin diacetate; the compositions of the polyol mixture and the isocyanate, and the percentages of the curing agent, the accelerator and the leveling agent in the major ingredients of the polyol mixture and the isocyanate in weight percentage are shown in the following table 1-1.

Comparative example 1

The difference from example 2 is that no levelling agent is added; the compositions of the polyol mixture and the isocyanate, and the percentages of the curing agent, the accelerator and the leveling agent in the major ingredients of the polyol mixture and the isocyanate in weight percent are shown in tables 1-2 below.

Comparative example 2

The difference from example 2 is that the spreading agent is replaced by an acrylic polysiloxane; the compositions of the polyol mixture and the isocyanate, and the percentages of the curing agent, the accelerator and the leveling agent in the major ingredients of the polyol mixture and the isocyanate in weight percent are shown in tables 1-2 below.

Comparative example 3

The difference from example 2 is that the polypropylene glycol ether is replaced by nonylphenol polyoxyethylene alcohol; the compositions of the polyol mixture and the isocyanate, and the percentages of the curing agent, the accelerator and the leveling agent in the major ingredients of the polyol mixture and the isocyanate in weight percent are shown in tables 1-2 below.

The results of the measurement of the properties of each example and comparative example are shown in Table 2 below, based on QB/T4197-2011 polyurethane resin for synthetic leather.

Solid content: the mass percentage of the rest part of the emulsion or the coating in the total amount is calculated after the emulsion or the coating is dried under the specified conditions.

Normal temperature bending: the leather has bending resistance or stretching resistance at normal temperature.

Hydrolysis resistance: and (3) evaluating the hydrolysis resistance degree of the sample according to the surface state change and the mechanical property change of the sample in the environment of certain temperature, humidity or alkali liquor with certain temperature and certain concentration after a specified time.

Modulus: refers to the ratio of stress to strain of a material under stress.

TABLE 1-1 component contents of examples and comparative examples

	Example 1	Example 2	Example 3	Example 4	Example 5
						Polytetrahydrofuran ether glycol	40％	50％	50％	45％	80％
Polypropylene glycol ether	30％	30％	20％	25％	-
						Isocyanates	30％	20％	30％	30％	20％
Curing agent (percentage of main material)	10％	20％	16％	15％	20％
						Accelerant (percentage of main material)	0.05％	0.5％	0.1％	0.2％	0.5％
Spreading agent (percentage of main material)	0.05％	0.5％	0.1％	0.3％	0.5％

Tables 1-2 component contents of examples and comparative examples

	Comparative example 1	Comparative example 2	Comparative example 3
				Polytetrahydrofuran ether glycol	50％	50％	50％
Polypropylene glycol ether	30％	30％	30％
				Isocyanates	20％	20％	20％
Curing agent (percentage of main material)	20％	20％	20％
				Accelerant (percentage of main material)	0.5％	0.5％	0.5％
Spreading agent (percentage of main material)	-	0.5％	0.5％

TABLE 2 results of performance test of each example and comparative example

As can be seen from table 2 above, when acrylic polysiloxane is used instead of or in place of the leveling agent, the number of normal-temperature flexings after leather formation is reduced, the modulus is also reduced, and the mechanical properties of the synthetic leather are affected.

After the polypropylene glycol ether is replaced by the nonylphenol polyoxyethylene alcohol, the hydrolysis resistance of the synthetic leather is poor, so that the polypropylene glycol ether can generate a good synergistic effect with the polytetrahydrofuran ether glycol, and the hydrolysis resistance stability of the synthetic leather is improved.

The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.