Soft and High Physical Property Organosilicon-Modified Waterborne Polyurethane and Its Preparation Method

Abstract

The present invention provides a silicone-modified aqueous polyurethane with soft and high physical properties and a preparation method thereof. The silicone-modified aqueous polyurethane comprises the following components in parts by weight: 0.34 to 0.42 parts of silicone diol, 5.5 to 6.8 parts of isocyanate monomer, 0.005 to 0.007 parts of organobismuth catalyst, 10 to 13 parts of polyol monomer, 1 to 1.2 parts of hydrophilic chain extender, 1.8 to 2.8 parts of high-boiling solvent, 0.6 to 0.78 parts of neutralizing agent, 30 to 32 parts of water, and 1 to 1.5 parts of amine chain extender. The aqueous polyurethane prepared by the raw material ratio and the preparation method disclosed by the present invention not only has high gloss, excellent dry and wet rubbing resistance and wear resistance, but also has a soft and full hand feeling. It can be applied to fields such as leather and textile, and can also be used on other soft substrates.

Description

Technical Field

[0001] The present invention relates to the field of aqueous polyurethane (PUD, Polyurathane Dispersion) for leather and textile, and more specifically, to a silicone-modified aqueous polyurethane with softness and high physical properties and a preparation method thereof. Background Art

[0002] Aqueous polyurethane is an environmentally friendly material with water as the dispersion medium. Due to the rich variety of raw materials it can choose, it has great advantages in film-forming properties, flexibility, water resistance, anti-sticking properties, etc. In recent years, with the continuous strengthening of the country's environmental protection policies and the improvement of people's environmental protection awareness, aqueous polyurethane is being widely used in the fields of leather, textile, plastic, ink, etc.

[0003] In the prior art, although aqueous polyurethane has the advantages of good flexibility, water resistance and anti-sticking property. However, due to the large number of hydrogen bonds in the molecular chain of aqueous polyurethane, the tensile strength after film formation is large, and it cannot meet the requirement of a plump and soft hand feeling when used in textile leather. If the tensile strength is simply reduced, it is easy to cause the film to be too soft and sticky, not only failing to meet the hand feeling requirements, but also unable to meet the actual use requirements of physical properties such as dry and wet rubbing resistance and abrasion resistance. Summary of the Invention

[0004] In view of the problems in the background art, the purpose of the present invention is to provide a silicone-modified aqueous polyurethane with softness and high physical properties and a preparation method thereof, which not only has high gloss, excellent dry and wet rubbing resistance and abrasion resistance, but also has a soft and plump hand feeling. It can be applied to the fields of leather and textile, etc., and can also be used on other soft substrates.

[0005] In order to achieve the above purpose, in the first aspect, the present invention provides a silicone-modified aqueous polyurethane with softness and high physical properties, comprising the following components in parts by weight: 0.34 - 0.42 parts of silicone diol, 5.5 - 6.8 parts of isocyanate monomer, 0.005 - 0.007 parts of organic bismuth catalyst, 10 - 13 parts of polyol monomer, 1 - 1.2 parts of hydrophilic chain extender, 1.8 - 2.8 parts of high-boiling solvent, 0.6 - 0.78 parts of neutralizer, 30 - 32 parts of water, 1 - 1.5 parts of amine chain extender.

[0006] Optionally, the water content of the silicone diol, isocyanate monomer, organic bismuth catalyst, polyol monomer, hydrophilic chain extender, high-boiling solvent, and neutralizer is less than 500 ppm.

[0007] Optionally, the silicone diol is at least one of Y16409, Innova 8660, and Silok-8815.

[0008] Optionally, the isocyanate monomer is at least one of isophorone diisocyanate (IPDI) and 4,4'-dicyclohexylmethane diisocyanate (HMDI).

[0009] Optionally, the organobismuth catalyst is at least one of TK 716 and Bi 20.

[0010] Optionally, the polyol monomer is at least one of polytetrahydrofuran ether diol (PTMEG 2000), polyester diol (PHA 2000), and polycaprolactone diol (PCL 2000).

[0011] Optionally, the hydrophilic chain extender is at least one of dimethylolpropionic acid DMPA and dimethylolbutyric acid DMBA; the high-boiling solvent is at least one of dimethylacetamide (DMAc) and N-ethylpyrrolidone (NEP).

[0012] Optionally, the neutralizing agent is at least one of triethylamine and dimethylethanolamine.

[0013] Optionally, the amine chain extender is at least one of hydrazine hydrate and ethylenediamine.

[0014] To achieve the above object, in a second aspect, the present invention provides a method for preparing the silicone-modified aqueous polyurethane with soft high physical properties as described above, comprising the following steps: S1: After uniformly mixing the silicone diol, isocyanate monomer, and catalyst, reacting at 75-110 °C for 2-3 h until the residual amount of NCO groups reaches 31% - 33% to obtain an intermediate; S2: Adding a hydrophilic chain extender, polyol monomer, and high-boiling solvent to the above intermediate, and then controlling the temperature within 75-110 °C and stirring and reacting for 2-3 h until the NCO groups reach 3.95% - 5.2% to obtain a polyurethane prepolymer; S3: Cooling the above prepolymer to 60-75 °C, adding a neutralizing agent to the system, stirring evenly, and slowly pouring it into a beaker pre-filled with deionized water, continuously stirring at a medium speed, completing within 5-15 min, and then adding an amine chain extender for chain extension and stirring for 30-120 min to obtain a polyurethane emulsion.

[0015] The beneficial effects of the present invention are as follows:

[0016] The present invention uses a polyether-modified silicone monomer with a hydroxyl group at both ends and an ABA-type block linear structure to modify waterborne polyurethane. The silicone segment is in the main chain, and the silicon content therein is between 30% and 60%. This structure can endow the coating with excellent softness and slipperiness, reduce the friction coefficient during dry and wet rubbing tests, thereby improving the dry and wet rubbing resistance and wear resistance. When used as a leather finishing agent for spraying leather, the obtained genuine leather has both the characteristics of softness, fullness and high physical properties, achieving a balance between the two. However, it is difficult for the waterborne polyurethane prepared by the ordinary method to have both performances when used as a leather finishing agent.

[0017] When the waterborne polyurethane prepared by using the raw material ratio and preparation method of the present invention is used as a leather finishing agent on genuine leather, it can meet the comfort requirements of leather products and the physical property requirements during long-term use. The waterborne polyurethane product provided by the present invention can also be applied to other soft substrate fields such as textiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a physical picture of the waterborne polyurethane emulsion prepared in Example 2 after the wet rubbing test after spraying leather.

[0020] Figure 2 It is a physical picture of the waterborne polyurethane emulsion prepared in Example 2 after the abrasion resistance test after spraying leather.

[0021] Figure 3 It is a physical picture of the waterborne polyurethane emulsion prepared in Comparative Example 1 after the wet rubbing test after spraying leather.

[0022] Figure 4 It is a physical picture of the waterborne polyurethane emulsion prepared in Comparative Example 1 after the abrasion resistance test after spraying leather. DETAILED DESCRIPTION OF THE INVENTION

[0023] In order to make the above objects, features and advantages of the invention more obvious and understandable, the following detailed description of the specific embodiments of the invention is given.

[0024] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0025] First, a silicone-modified aqueous polyurethane with soft and high physical properties according to the first aspect of the present invention is described. It comprises the following components in parts by weight: 0.34 - 0.42 parts of silicone diol, 5.5 - 6.8 parts of isocyanate monomer, 0.005 - 0.007 parts of organobismuth catalyst, 10 - 13 parts of polyol monomer, 1 - 1.2 parts of hydrophilic chain extender, 1.8 - 2.8 parts of high-boiling solvent, 0.6 - 0.78 parts of neutralizing agent, 30 - 32 parts of water, and 1 - 1.5 parts of amine chain extender. Among them, the water content of the silicone diol, isocyanate monomer, organobismuth catalyst, polyol monomer, hydrophilic chain extender, high-boiling solvent, and neutralizing agent is all lower than 500 ppm. The silicone diol can be at least one of Y16409, Innova 8660, and Silok-8815. The isocyanate monomer can be at least one of isophorone diisocyanate (IPDI) and 4,4'-dicyclohexylmethane diisocyanate (HMDI). The organobismuth catalyst can be at least one of TK 716 and Bi 20. The polyol monomer can be at least one of polytetrahydrofuran ether diol (PTMEG2000), polyester diol (PHA 2000), and polycaprolactone diol (PCL 2000). The hydrophilic chain extender can be at least one of dimethylolpropionic acid (DMPA) and dimethylolbutyric acid (DMBA); the high-boiling solvent is at least one of dimethylacetamide (DMAc) and N-ethylpyrrolidone (NEP). The neutralizing agent can be at least one of triethylamine and dimethylethanolamine. The amine chain extender can be at least one of hydrazine hydrate and ethylenediamine.

[0026] Secondly, a preparation method of the silicone-modified aqueous polyurethane with soft and high physical properties according to the second aspect of the present invention is described. It comprises the following steps: S1: After uniformly mixing the silicone diol, isocyanate monomer, and catalyst, react at 75 - 110°C for 2 - 3 h until the residual amount of NCO groups reaches 31% - 33% to obtain an intermediate; S2: Add the hydrophilic chain extender, polyol monomer, and high-boiling solvent to the above intermediate, and then control the temperature within 75 - 110°C and stir and react for 2 - 3 h until the NCO groups reach 3.95% - 5.2% to obtain a polyurethane prepolymer; S3: Cool the above prepolymer to 60 - 75°C, add the neutralizing agent to the system, stir evenly, and then pour it into a beaker pre-filled with deionized water at a constant speed, and complete it within 5 - 15 min under continuous medium-speed stirring. Then add the amine chain extender for chain extension and stir for 30 - 120 min to obtain a polyurethane emulsion.

[0027] The preparation method adopted by the present invention is to first react silicone with isocyanate to obtain an intermediate, and then add soft segment monomers and hydrophilic chain extenders to prepare a prepolymer. The advantage of this preparation method is that it can obtain a polymer with a definite sequence structure, making the aqueous polyurethane have a stable hand feeling. If the one-pot method is used, since the distribution of silicone monomer segments is random each time, the stability and repeatability of the hand feeling are very uncontrollable. The silicone diol with a specific structure selected in the present invention is a polyether-modified silicone monomer with a hydroxyl group at both ends and an ABA-type block linear structure (the structural formula is shown below). Its silicone segment is in the molecular main chain and the content is between 30% and 60%. Selecting this kind of silicone structure can bring a moderately soft and plump hand feeling to the prepared aqueous polyurethane in the application of leather finishing agents.

[0028]

[0029] When monomers with too high a silicon content are selected, or monomers with silicone segments in the side chain are selected for modification, the prepared aqueous polyurethane, after being used as a leather finishing agent, will have too much oily feeling and too large viscosity on the leather due to more silicone migrating to the surface, thus unable to meet the use requirements.

[0030] A soft and high-property silicone-modified aqueous polyurethane and its preparation method provided by the present invention use specific proportions of silicone diol, isocyanate monomer, organic bismuth catalyst, polyol monomer, hydrophilic chain extender, high-boiling solvent, neutralizer and amine chain extender as the main raw materials, and are prepared in three steps. By controlling the reaction temperature of the first two steps and detecting the content of NCO (isocyanate group) groups to determine the reaction time and reaction end point; adding a neutralizer for neutralization, and then uniformly pouring it into water and stirring, which is completed within 5 to 15 minutes. After that, hydrazine hydrate is added for chain extension, and continuous medium-speed stirring is carried out for 30 to 120 min to obtain the final polyurethane emulsion.

[0031] The present invention determines the preparation process of the prepolymer by controlling the reaction temperature and the amount of residual NCO groups, and then neutralizes and emulsifies to control the production process of the aqueous resin. The synthesized aqueous polyurethane resin not only has high gloss, excellent dry and wet rubbing resistance and wear resistance, but also has a soft and plump hand feeling. It can be widely applied to fields such as textile leather, and can also be used on other soft substrates.

[0032] Hereinafter, the soft and high-property silicone-modified aqueous polyurethane and its preparation method of the present invention will be specifically described in conjunction with specific embodiments.

[0033] Example 1

[0034] The preparation method of the soft and high-property silicone-modified aqueous polyurethane provided in this example may include the following steps:

[0035] S1: Stir and mix Y16409, HMDI, IPDI, and TK716 evenly, heat up to 95 °C, after reacting for 2 h, take a sample to measure the NCO value, and the result is 32.12%, obtaining an intermediate;

[0036] S2: Add PTMEG2000, DMPA, and NEP to the above intermediate, stir and react at 95 °C for 2 h, measure the NCO group content to be 4.23%, obtaining a polyurethane prepolymer;

[0037] S3: Cool the above prepolymer to 70 °C, add triethylamine for neutralization, then pour it into water evenly under medium-speed stirring conditions, complete it within 5 - 15 minutes, and then add hydrazine hydrate for chain extension, and continue medium-speed stirring for 30 min; namely, the final polyurethane emulsion is obtained.

[0038] Among them, the composition ratios of the raw materials used are shown in the following table:

[0039] Raw material Parts by mass Silicone diol Y16409 0.35 HMDI 3.34 IPDI 2.83 TK 716 0.007 PTMEG 2000 11.43 DMPA 1 NEP 2.09 Triethylamine 0.75 Water 30.93 Hydrazine hydrate (50%) 1.17

[0040] Example 2

[0041] The preparation method of the soft and high-property organosilicon-modified waterborne polyurethane provided in this example may include the following steps:

[0042] S1: Stir and mix Innovo 8660, HMDI, and TK716 evenly, heat up to 95 °C, after reacting for 2 h, take a sample to measure the NCO value, and the result is 31.52%, obtaining an intermediate;

[0043] S2: Add PHA2000, DMPA, and NEP to the above intermediate, stir and react at 95 °C for 2 h, measure the NCO group content to be 4.013%, obtaining a polyurethane prepolymer;

[0044] S3: Cool the above prepolymer to 70 °C, add triethylamine for neutralization, then pour it into water evenly under medium-speed stirring conditions, complete it within 5 - 15 minutes, and then add hydrazine hydrate for chain extension, and continue medium-speed stirring for 60 min; namely, the final polyurethane emulsion is obtained.

[0045] Among them, the composition ratios of the raw materials used are shown in the following table:

[0046] Raw material Parts by mass 8660 0.39 HMDI 6.67 TK 716 0.006 PHA 2000 11.43 DMPA 1 NEP 2.15 Triethylamine 0.75 Water 30.91 Hydrazine hydrate (50%) 1.07

[0047] Example 3

[0048] The preparation method of the soft and high-property organosilicon-modified waterborne polyurethane provided in this example may include the following steps:

[0049] S1: Stir and mix Silok-8815, IPDI, and Bi 20 evenly, heat up to 95 °C, after reacting for 2 h, take a sample to measure the NCO value, the result is 32.86%, and obtain an intermediate;

[0050] S2: Add polycaprolactone PCL2000, DMPA, and DMAc to the above intermediate, stir and react at 95 °C for 2 h, measure the NCO group content to be 4.654%, and obtain a polyurethane prepolymer;

[0051] S3: Cool the above prepolymer to 65 °C, add triethylamine for neutralization, then pour it into water evenly under medium-speed stirring conditions, complete within 5 - 15 minutes, and then add hydrazine hydrate for chain extension, and continue medium-speed stirring for 60 min; thus obtaining the final polyurethane emulsion.

[0052] Among them, the composition ratios of the raw materials used are shown in the following table:

[0053] Raw material Parts by mass Silok-8815 0.38 IPDI 5.66 Bi 20 0.005 PCL 2000 11.43 DMBA 1 NEP 2.09 Triethylamine 0.75 Water 30.91 Hydrazine hydrate (50%) 1.28

[0054] Example 4

[0055] The preparation method of the soft and high-property organosilicon-modified waterborne polyurethane provided in this example may include the following steps:

[0056] S1: Stir and mix Silok-8815, IPDI, and Bi 20 evenly, heat up to 95 °C, after reacting for 2 h, take a sample to measure the NCO value, the result is 32.86%, and obtain an intermediate;

[0057] S2: Add polycaprolactone PCL2000, DMPA, and DMAc to the above intermediate, stir and react at 95 °C for 2 h, measure the NCO group content to be 4.654%, and obtain a polyurethane prepolymer;

[0058] S3: Cool the above prepolymer to 65 °C, add triethylamine for neutralization, then pour it into water evenly under medium-speed stirring conditions, complete within 5 - 15 minutes, and then add hydrazine hydrate for chain extension, and continue medium-speed stirring for 60 min; thus obtaining the final polyurethane emulsion.

[0059] Among them, the composition ratios of the raw materials used are shown in the following table:

[0060] Raw material Parts by mass Silok-8815 0.38 IPDI 5.66 Bi 20 0.005 PCL 2000 11.43 DMBA 1 NEP 2.09 Triethylamine 0.75 Water 30.91 Hydrazine hydrate (50%) 1.28

[0061] Comparative Example 1

[0062] Except that Innova 8660 is not added, the rest is the same as in Example 1.

[0063] Performance Test

[0064] The leather sprayed with the aqueous polyurethane emulsion prepared in Examples 1-4 was subjected to the following tests.

[0065] 1. Wet rubbing test

[0066] The test conditions were wet rubbing 1000 times with a 9N weight.

[0067] 2. Abrasion resistance test

[0068] The test conditions were CS-10 test for 1000 times.

[0069] 3. Sensory performance evaluation

[0070] The sensory performance evaluation included gloss and softness and fullness evaluation, following GB / T 16799-2018 and GB / T 39371-2020. Experts scored the sensory performance, with scores ranging from 1 to 5 (5 being the best).

[0071] The performance test results are shown in Table 1.

[0072] Table 1 Performance test results

[0073]

[0074] Refer to Figure 1 and Figure 2 ( Figure 1 and Figure 2 The color pictures were black-and-white processed), it can be seen that after the wet rubbing test of the sample of Example 2, the paint film on the leather was not damaged and there was no color fading. From Figure 1 it can be seen that after the abrasion resistance test of the sample of Example 2, there was no obvious wear-through of the paint film. If silicone modification was not used or the selected silicone structure was inappropriate, the prepared aqueous polyurethane not only could not achieve a soft and full hand feeling, but also its wet and dry rubbing resistance and abrasion resistance performance would decrease significantly. As Figure 2 and Figure 3 and Figure 4 shown ( Figure 3 and Figure 4 The color pictures were black-and-white processed), after the wet rubbing test of the SA134 sample of Comparative Example 1, the paint film on the leather was damaged and there was color fading, as Figure 3 shown. After the abrasion resistance test of the SA134 sample of Comparative Example 1, there was obvious wear-through of the paint film, as Figure 4 shown.

[0075] It can be seen from the above examples that after spraying the leather with the aqueous polyurethane emulsion prepared by the present invention as a finishing agent, the wet rubbing resistance and abrasion resistance of the leather are improved, it has high gloss, and also has a soft and full hand feeling.

[0076] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and not for limiting the scope of the present invention. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A preparation method of a silicone-modified aqueous polyurethane with high physical properties and softness, characterized in that, It includes the following steps: S1: After uniformly mixing silicone diol, isocyanate monomer, and organobismuth catalyst, react at 75 - 110 °C for 2 - 3 h until the residual amount of NCO groups reaches 31% - 33% to obtain an intermediate; S2: Add a hydrophilic chain extender, polyol monomer, and high-boiling solvent to the above intermediate, then control the temperature within 75 - 110 °C and stir and react for 2 - 3 h until the NCO groups reach 3.95% - 5.2% to obtain a polyurethane prepolymer; S3: Cool the above prepolymer to 60 - 75 °C, add a neutralizing agent to the system, stir evenly, and then pour it uniformly into a beaker pre-filled with deionized water, continuously stir at a medium speed, and complete it within 5 - 15 min. Then add an amine chain extender for chain extension and stir for 30 - 120 min to obtain a polyurethane emulsion; The silicone diol is a polyether-modified silicone monomer with hydroxyl groups at both ends and an ABA-type block linear structure, and its silicone segment is in the molecular main chain with a content between 30% and 60%. The structural formula is as follows: ； The polyol monomer is at least one of polytetrahydrofuran ether diol PTMEG 2000, polyester diol PHA 2000, and polycaprolactone diol PCL 2000; The high-boiling solvent is at least one of dimethylacetamide DMAc and N-ethylpyrrolidone NEP.

2. The preparation method of the silicone-modified aqueous polyurethane with soft high physical properties according to claim 1, characterized in that, The raw materials are by weight: 0.34 - 0.42 parts of silicone diol, 5.5 - 6.8 parts of isocyanate monomer, 0.005 - 0.007 parts of organobismuth catalyst, 10 - 13 parts of polyol monomer, 1 - 1.2 parts of hydrophilic chain extender, 1.8 - 2.8 parts of high-boiling solvent, 0.6 - 0.78 parts of neutralizing agent, 30 - 32 parts of water, and 1 - 1.5 parts of amine chain extender.

3. The preparation method of the soft and high-property silicone-modified waterborne polyurethane according to claim 1, wherein The water content of silicone diol, isocyanate monomer, organobismuth catalyst, polyol monomer, hydrophilic chain extender, high-boiling solvent, and neutralizing agent is all lower than 500 ppm.

4. The preparation method of the silicone-modified aqueous polyurethane with soft high physical properties according to claim 1, characterized in that The isocyanate monomer is at least one of isophorone diisocyanate IPDI and 4,4'-dicyclohexylmethane diisocyanate HMDI.

5. The preparation method of the silicone-modified aqueous polyurethane with high physical properties as claimed in claim 1, wherein The organobismuth catalyst is at least one of TK 716 and Bi 20.

6. The preparation method of the silicone-modified aqueous polyurethane with soft high physical properties according to claim 1, characterized in that, The hydrophilic chain extender is at least one of dimethylolpropionic acid DMPA and dimethylolbutyric acid DMBA.

7. The preparation method of the silicone-modified aqueous polyurethane with soft high physical properties according to claim 1, characterized in that, The neutralizing agent is at least one of triethylamine and dimethylethanolamine.

8. The preparation method of the silicone-modified aqueous polyurethane with high physical properties as described in claim 1, characterized in that, The amine chain extender is at least one of hydrazine hydrate and ethylenediamine.

Images