A water-based polyurethane dispersion for high color fastness printing, and its preparation method and use

Abstract

The present invention provides an aqueous polyurethane dispersion for improving the color fastness of printed fabrics, as well as its preparation method and use. The aqueous polyurethane dispersion grafts dye molecules onto molecular chains during the prepolymerization stage, creating a synergistic effect with animal glue added before chain extension to enhance the bonding between the dye and the molecular chains, achieving high color fastness requirements for printed fabrics. The addition of stearates further enhances the color fastness and smoothness of the printed fabrics.

Description

Technical Field

[0001] The invention belongs to the field of water-based polyurethane materials, and particularly relates to a water-based polyurethane dispersion for improving the color fastness of printing, a preparation method and application thereof. Background Art

[0002] Printing with water-based polyurethane dispersions requires only drying and no washing, making the process simple, reducing solvent and wastewater emissions and meeting environmental protection requirements. Water-based polyurethane dispersions can form a dense, transparent film on the fabric surface, which has good adhesion and elasticity.

[0003] As people's living standards improve, their requirements for clothing and shoe materials are becoming increasingly demanding. Therefore, the color fastness of printing on clothing and shoe materials has become a major concern. Previously, the printing process involved physically dispersing color paste into a resin to create a printing resin. However, this method often results in poor color fastness. Therefore, a resin that can improve the color fastness of printing is needed.

[0004] CN108867113A discloses a paint printing adhesive and its preparation method. The method uses polytetramethylene glycol, hydroxyl-terminated polydimethylsiloxane, polycarbonate diol, polycaprolactone, polypropylene glycol, and dimethylolpropionic acid as soft segments, and MDI and IPDI as hard segments to prepare a water-based coating. Chitosan, furcellaran, sodium alginate, and fatty amine polyoxyethylene ether are then added and mixed to produce a coating paste. This method does not chemically bond the pigment to the resin, and color fastness during application remains problematic. Therefore, the issue of printing color fastness remains unresolved. Summary of the Invention

[0005] The present invention aims to provide an aqueous polyurethane dispersion for improving the color fastness of printed fabrics. This aqueous polyurethane dispersion achieves a better bond between the resin and the dye by grafting dye molecules onto the molecular chain during the prepolymerization stage. This creates a synergistic effect with the animal glue added before chain extension, thereby meeting the resin's requirement for high color fastness in the printing direction. In a preferred embodiment, the addition of stearates further improves the color fastness and smoothness of the printed fabric.

[0006] To achieve the above objectives, the present invention adopts the following technical solutions:

[0007] A water-based polyurethane dispersion for improving the color fastness of printing, comprising the following raw materials:

[0008] a. Polyisocyanate, added in an amount of 18-28wt%, preferably 20-25wt%;

[0009] b. Polyol, added in an amount of 28-41 wt%, preferably 32-38 wt%;

[0010] c. Hydroxyl-containing pigment, added in an amount of 20-30wt%, preferably 20-25wt%;

[0011] d. Small molecule polyol chain extender, added in an amount of 1-6 wt%, preferably 1.5-4 wt%;

[0012] e. a hydrophilic chain extender containing active hydrogen, added in an amount of 1-6%, preferably 2-5wt%;

[0013] f. Animal glue, added in an amount of 10-20wt%, preferably 10-15wt%;

[0014] g. A small molecule polyamine chain extender containing active hydrogen, added in an amount of 1-6 wt%, preferably 2-5 wt%;

[0015] The percentages of the above raw materials are based on the weight of the solid content of the waterborne polyurethane resin.

[0016] As a preferred solution, the raw materials of the aqueous polyurethane dispersion may further include component h: one or more of glycerol stearate, sorbitan monostearate, and ethylene glycol distearate, with an addition amount of 1-6wt%, preferably 2-5wt%. The addition of the above stearates is beneficial to further improve the color fastness and smoothness of the print.

[0017] In the present invention, component a is selected from aliphatic and / or alicyclic isocyanates, preferably one or more of isophorone diisocyanate, 1,6-hexyl diisocyanate, dicyclohexylmethane diisocyanate and tetramethylxylene diisocyanate, more preferably dicyclohexylmethane diisocyanate and isophorone diisocyanate. These two isocyanates can act synergistically, thereby improving the overall performance of the dispersion.

[0018] In the present invention, component b is a polyol with a number average molecular weight of 100-5000, selected from one or more of polytetramethylene glycol, polyethylene glycol diol, polypropylene glycol diol and polyethylene glycol-propylene glycol diol, polyethylene oxide polyol, polypropylene oxide polyol and polysiloxane polyol; preferably one or more of polypropylene glycol diol and / or polytetramethylene glycol diol with a number average molecular weight of 300-3000.

[0019] In the present invention, component c is selected from one or more of Acid Rose Bengal B, Acid Red 52, and trisodium 8-hydroxy-1,3,6-pyrenetrisulfonate.

[0020] In the present invention, component d is a small molecule polyol with a molecular weight of 20-100, selected from one or more of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, diethylene glycol, neopentyl glycol, 1,6-hexanediol, 2,3-butanediol, neopentyl glycol, diethylene glycol and 1,4-cyclohexanedimethanol, preferably 1,4-butanediol and / or 1,6-hexanediol.

[0021] In the present invention, component e is selected from one or more of dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolvaleric acid and dimethyloloctanoic acid, preferably dimethylolbutanoic acid.

[0022] In the present invention, component f is selected from one or more of bovine bone gelatin and gelatin.

[0023] In the present invention, component g is selected from one or more of ethylenediamine, propylenediamine, hexamethylenediamine, hexamethylenediamine, 4,4-diphenylmethanediamine, hydroxyethylethylenediamine, di-n-butylamine, isophoronediamine and 1,3-bis[(trihydroxymethyl)methylamino]propane, preferably one or more of 1,3-bis[(trihydroxymethyl)methylamino]propane, hydroxyethylethylenediamine and isophoronediamine.

[0024] In the present invention, the solid content of the dispersion is 45-55 wt%, preferably 50-55 wt%, and the particle size of the dispersion is 50-200 nm, preferably 100-150 nm.

[0025] In the present invention, the preparation method of the aqueous polyurethane dispersion comprises the following preparation steps:

[0026] (1) Components a, b, and c are mixed and reacted at a temperature of 80-95°C to form a prepolymer;

[0027] (2) Adding components d and e, acetone, and a catalyst to the prepolymer for chain extension, the reaction temperature is 75-85°C, and after reaching the theoretical NCO% the temperature is lowered, and acetone is added for dilution;

[0028] (3) adding deionized water for dispersion under high-speed shearing;

[0029] (4) Add components f and h, add component g for chain extension, remove acetone, and obtain a waterborne polyurethane dispersion product.

[0030] In the method of the present invention, the catalyst is selected from an organic bismuth catalyst, such as bismuth isooctanoate, bismuth laurate, bismuth neodecanoate, preferably one or more of organic bismuth Coscat83, organic bismuth 1610, organic bismuth 2010, organic bismuth 2810 and organic bismuth 2808.

[0031] In the present invention, the dispersion prepared by the above method can be used in the fields of clothing, shoe materials, ink, etc. that have high requirements for printing color fastness.

[0032] The positive effects of the present invention are mainly reflected in the following aspects:

[0033] The aqueous polyurethane dispersion of the present invention achieves a better combination of resin and dye by grafting dye molecules onto the molecular chain in the prepolymerization stage, which produces a synergistic effect with the animal glue added before the chain extension, thereby meeting the high color fastness requirement of this resin in the printing direction. The addition of stearates is beneficial to further improve the color fastness and smoothness of the printing. DETAILED DESCRIPTION

[0034] The testing method in the present invention is as follows:

[0035] Particle size testing method: Malvern particle size analyzer.

[0036] Viscosity test method: Brookfield viscometer, rotor No. 3, speed 30 rpm.

[0037] Color fastness to rubbing: measured according to GB / T3920-2008 “Textiles—Tests for Color Fastness—Color Fastness to Rubbing”.

[0038] Color fastness to washing with soap: according to GB / T-2008 "Textiles - Tests for color fastness - Color fastness to washing with soap".

[0039] Smoothness: Select 10 people to rate the printed samples in turn and take the average value.

[0040] The construction process for preparing fabric printing with dispersion is as follows:

[0041] Use hand screen printing, silk screen printing or rotary screen printing, two passes and four cuts. The samples are cured in a 50℃ oven for 24 hours before testing.

[0042] The fabric printing construction formula is as follows:

[0043]

[0044] The raw materials used in the examples are as follows:

[0045] HMDI (dicyclohexylmethane diisocyanate, NCO% content of about 32.0%, Wanhua Chemical Group Co., Ltd.);

[0046] IPDI (isophorone diisocyanate, NCO% content of about 37.8%, Wanhua Chemical Group Co., Ltd.);

[0047] PPG2000 (polypropylene glycol, hydroxyl value 56 mgKOH / g, number average molecular weight ≈ 2000, functionality 2, Dongda Chemical);

[0048] PTMG2000 (polytetramethylene glycol, hydroxyl value 56 mgKOH / g, number average molecular weight 2000, functionality 2, Yantai Huada Chemical);

[0049] PTMG1000 (polytetramethylene glycol, hydroxyl value 112 mgKOH / g, number average molecular weight 1000, functionality 2, Yantai Huada Chemical);

[0050] Trisodium 8-hydroxy-1,3,6-pyrenetrisulfonate (Shanghai Linen Technology Development Co., Ltd.)

[0051] Acid Rose Red B (Tianjin Zhaobo Chemical Co., Ltd.)

[0052] Bovine bone gelatin (Hengshui Qianlong Gelatin Technology Co., Ltd.)

[0053] Gelatin (Hengshui Qianlong Gelatin Technology Co., Ltd.)

[0054] HDO (1,6-hexanediol, BASF, Germany);

[0055] BDO (1,4-butanediol, BASF, Germany);

[0056] Dimethylolbutyric acid (Analytical grade, J&K Technology Co., Ltd.)

[0057] IPDA (isophorone diamine, BASF, Germany);

[0058] EDA (ethylenediamine, BASF, Germany);

[0059] 1,3-Bis[(trishydroxymethyl)methylamino]propane (chain extender, Dalian Meilun Biotechnology Co., Ltd.);

[0060] Organic bismuth Coscat83: Leading American chemical company, analytical grade

[0061] A801 (alkali thickener, Wanhua Chemical Group Co., Ltd.);

[0062] U605 (polyurethane associative thickener, Wanhua Chemical Group Co., Ltd.).

[0063] Example 1

[0064] To a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer were added 30 g of IPDI, 20 g of HDI, 35 g of PPG2000, 20 g of PTMG2000, 15 g of PTMG1000 and 43 g of trisodium 8-hydroxy-1,3,6-pyrenetrisulfonate. The mixture was reacted at 80° C. for 1 h, and the NCO content was measured to obtain a prepolymer.

[0065] Cool to 60°C, add 2g BDO, 2g HDO, 4.7g dimethylolbutyric acid, 0.3g organic bismuth Coscat83, and 40g acetone to dilute, stir evenly, and heat to 80°C to react. Stop the reaction when the theoretical NCO% is reached. Cool to 60°C, add 50g acetone to dilute, stir and mix for 5 minutes, and continue cooling to 30-35°C.

[0066] 173 g of deionized water was added for dispersion.

[0067] 30 g of gelatin was added and stirred evenly. 5 g of isophorone diamine and 6 g of 1,3-bis[(trihydroxymethyl)methylamino]propane were diluted with 40 g of deionized water and slowly added to the system. The mixture was reacted at a constant temperature of 35°C for 5 min. The obtained emulsion was distilled under reduced pressure to remove acetone to obtain an aqueous polyurethane emulsion with a particle size of 110 nm and obvious blue light.

[0068] Example 2

[0069] 20 g IPDI, 23 g HDI, 20 g PPG2000, 60 g PTMG1000 and 45 g Acid Rose Bengal B were added to a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer. After reacting at 80° C. for 1 h, the NCO content was measured to obtain a prepolymer.

[0070] Cool to 60°C, add 4g BDO, 4g HDO, 9.2g dimethylolbutyric acid, 0.8g organic bismuth Coscat83, and 40g acetone to dilute, stir evenly, and heat to 80°C. Stop the reaction when the theoretical NCO% is reached. Cool to 60°C, add 50g acetone to dilute, stir and mix for 5 minutes to thoroughly mix the prepolymer and acetone, and continue to cool to 30-35°C.

[0071] 173 g of deionized water was added for dispersion.

[0072] 22 g of bovine bone gelatin was added and stirred evenly. 2 g of isophorone diamine and 3 g of 1,3-bis[(trihydroxymethyl)methylamino]propane were diluted with 40 g of deionized water and slowly added to the system. The mixture was reacted at a constant temperature of 35°C for 5 min. The obtained emulsion was distilled under reduced pressure to remove acetone to obtain a water-based polyurethane emulsion with a particle size of 120 nm and obvious blue light.

[0073] Example 3

[0074] To a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer were added 15 g of IPDI, 38 g of HDI, 35 g of PPG2000, 35 g of PTMG2000, 15 g of PTMG1000 and 53 g of trisodium 8-hydroxy-1,3,6-pyrenetrisulfonate. The mixture was reacted at 80° C. for 1 h, and the NCO content was measured to obtain a prepolymer.

[0075] Cool to 60°C, add 1g BDO, 2.5g HDO, 4.5g dimethylolbutyric acid, 0.4g organic bismuth Coscat83, and 40g acetone to dilute, stir evenly, and heat to 80°C. Stop the reaction when the theoretical NCO% is reached. Cool to 60°C, add 50g acetone to dilute, stir and mix for 5 minutes to thoroughly mix the prepolymer and acetone, and continue to cool to 30-35°C.

[0076] 148 g of deionized water was added for dispersion.

[0077] 24.6 g of bovine bone gelatin was added and stirred evenly. 3 g of isophorone diamine and 3 g of 1,3-bis[(trihydroxymethyl)methylamino]propane were diluted with 40 g of deionized water and slowly added to the system. The mixture was reacted at a constant temperature of 35°C for 5 min. The obtained emulsion was distilled under reduced pressure to remove acetone to obtain a water-based polyurethane emulsion with a particle size of 100 nm and obvious blue light.

[0078] Example 4

[0079] 50 g of IPDI, 70 g of PPG2000, and 49.2 g of trisodium 8-hydroxy-1,3,6-pyrenetrisulfonate were added to a four-necked flask equipped with a reflux condenser, a thermometer, and a mechanical stirrer. The mixture was reacted at 80° C. for 1 h, and the NCO content was measured to obtain a prepolymer.

[0080] Cool to 60°C, add 6g BDO, 5g dimethylolbutyric acid, 0.8g organic bismuth Coscat83, and 40g acetone to dilute, stir evenly, and heat to 80°C. Stop the reaction when the theoretical NCO% is reached. Cool to 60°C, add 50g acetone to dilute, stir and mix for 5 minutes to thoroughly mix the prepolymer and acetone, and continue to cool to 30-35°C.

[0081] 173 g of deionized water was added for dispersion.

[0082] 22 g of bovine gelatin and 5 g of sorbitan monostearate were added and stirred evenly. 5 g of 1,3-bis[(trihydroxymethyl)methylamino]propane was diluted with 40 g of deionized water and slowly added to the system. The mixture was reacted at a constant temperature of 35°C for 5 min. The obtained emulsion was distilled under reduced pressure to remove acetone to obtain an aqueous polyurethane emulsion with a particle size of 100 nm and obvious blue light.

[0083] Example 5

[0084] 43 g of IPDI, 72.6 g of PTMG1000, and 43 g of Acid Rose Bengal B were added to a four-necked flask equipped with a reflux condenser, a thermometer, and a mechanical stirrer. The mixture was reacted at 80° C. for 1 h, and the NCO content was measured to obtain a prepolymer.

[0085] Cool to 60°C, add 4g HDO, 10g dimethylolbutyric acid, 0.4g organic bismuth Coscat83, and 40g acetone to dilute, stir evenly, and heat to 80°C. Stop the reaction when the theoretical NCO% is reached. Cool to 60°C, add 50g acetone to dilute, stir and mix for 5 minutes to fully mix the prepolymer and acetone, and continue to cool to 30-35°C.

[0086] 148 g of deionized water was added for dispersion.

[0087] Add 22g gelatin, 4g glycerol stearate, and 4g ethylene glycol distearate and stir evenly. Dilute 10g isophorone diamine with 40g deionized water and slowly add it to the system. React at 35°C for 5min. Distill the obtained emulsion under reduced pressure to remove acetone to obtain a water-based polyurethane emulsion with a particle size of 100nm and obvious blue light.

[0088] Comparative Example 1

[0089] 30 g IPDI, 20 g HDI, 35 g PPG2000, 20 g PTMG2000 and 15 g PTMG1000 were added to a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer. After reacting at 80° C. for 1 h, the NCO content was measured to obtain a prepolymer.

[0090] Cool to 60°C, add 2g BDO, 2g HDO, 4.7g dimethylolbutyric acid, 0.3g organic bismuth Coscat83, and 40g acetone to dilute, stir evenly, and heat to 80°C. Stop the reaction when the theoretical NCO% is reached. Cool to 60°C, add 50g acetone to dilute, stir and mix for 5 minutes to thoroughly mix the prepolymer and acetone, and continue to cool to 30-35°C.

[0091] 173 g of deionized water was added for dispersion.

[0092] 30 g of gelatin was added and stirred evenly. 5 g of isophorone diamine and 6 g of 1,3-bis[(trihydroxymethyl)methylamino]propane were diluted with 40 g of deionized water and slowly added to the system. The mixture was reacted at a constant temperature of 35°C for 5 min. 43 g of trisodium 8-hydroxy-1,3,6-pyrenetrisulfonate was added and stirred evenly. The obtained emulsion was distilled under reduced pressure to remove acetone to obtain an aqueous polyurethane emulsion with a particle size of 100 nm and obvious blue light.

[0093] Comparative Example 2

[0094] To a four-necked flask equipped with a reflux condenser, a thermometer and a mechanical stirrer were added 25.8 g of IPDI, 17 g of HDI, 30 g of PPG2000, 17 g of PTMG2000, 12.9 g of PTMG1000 and 37 g of trisodium 8-hydroxy-1,3,6-pyrenetrisulfonate. The mixture was reacted at 80° C. for 1 h, and the NCO content was measured to obtain a prepolymer.

[0095] Cool to 60°C, add 1.7g BDO, 1.7g HDO, 4g dimethylolbutyric acid, 0.2g organic bismuth Coscat83, and 40g acetone to dilute, stir evenly, and heat to 80°C. Stop the reaction when the theoretical NCO% is reached. Cool to 60°C, add 50g acetone to dilute, stir and mix for 5 minutes to thoroughly mix the prepolymer and acetone, and continue to cool to 30-35°C.

[0096] 116.7 g of deionized water was added for dispersion.

[0097] 4.3 g of isophorone diamine and 5 g of 1,3-bis[(trihydroxymethyl)methylamino]propane were diluted with 40 g of deionized water and slowly added to the system. The mixture was reacted at a constant temperature of 35°C for 5 min. The acetone was removed from the obtained emulsion by vacuum distillation to obtain a water-based polyurethane emulsion with a particle size of 110 nm and obvious blue light.

[0098] The dispersions in the examples and comparative examples were used to prepare fabric printing according to the above fabric printing construction formula. The properties of the samples after construction are shown in Table 1:

[0099] Table 1 Properties of fabric printing samples prepared from dispersions in Examples and Comparative Examples

[0100]

[0101] Rating: 1-5, 1 is the worst and 5 is the best.

Claims

1. A water-based polyurethane dispersion for printing with high color fastness, prepared by reacting the following raw materials, based on the solid weight: a. Polyisocyanate, added in an amount of 18-28 wt%; b, polyol, added in an amount of 28-41wt%; component b is a polyol having a number average molecular weight of 100-5000, selected from one or more of polytetramethylene glycol, polyethylene glycol diol, polypropylene glycol diol, polyethylene glycol-propylene glycol diol, and polysiloxane polyol; c. Hydroxyl-containing pigment 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium, added in an amount of 20-30wt%; d. a small molecule polyol chain extender, added in an amount of 1-6 wt %; component d is selected from one or more of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 2,3-butanediol, diethylene glycol, and 1,4-cyclohexanedimethanol; e. Hydrophilic chain extender containing active hydrogen, added in an amount of 1-6%; f. Animal glue, added in an amount of 10-20wt%; g. Small molecule polyamine chain extender containing active hydrogen, added in an amount of 1-6 wt%.

2. The dispersion according to claim 1, characterized in that The reaction preparation contains the following raw materials, based on the solid weight: a. Polyisocyanate, added in an amount of 20-25wt%; b. Polyol, added in an amount of 32-38 wt%; c. hydroxyl-containing pigment 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium, added in an amount of 20-25wt%; d. Small molecule polyol chain extender, added in an amount of 1.5-4wt%; e. A hydrophilic chain extender containing active hydrogen, added in an amount of 2-5 wt%; f. Animal glue, added in an amount of 10-15wt%; g. Small molecule polyamine chain extender containing active hydrogen, added in an amount of 2-5wt%.

3. The dispersion according to claim 1 or 2, characterized in that Component a is selected from aliphatic and / or alicyclic isocyanates.

4. The dispersion according to claim 3, characterized in that Component a is selected from one or more of isophorone diisocyanate, 1,6-hexyl diisocyanate, and dicyclohexylmethane diisocyanate.

5. The dispersion according to claim 1 or 2, characterized in that Component e is selected from one or more of dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolvaleric acid and dimethyloloctanoic acid.

6. The dispersion according to claim 1 or 2, characterized in that Component d is selected from one or more of 1,4-butanediol and 1,6-hexanediol.

7. The dispersion according to claim 1 or 2, characterized in that Component f is selected from one or more of bovine bone gelatin and gelatin.

8. The dispersion according to claim 1 or 2, characterized in that Component g is selected from one or more of ethylenediamine, propylenediamine, hexamethylenediamine, 4,4'-diphenylmethanediamine, hydroxyethylethylenediamine, isophoronediamine and 1,3-bis[(trihydroxymethyl)methylamino]propane.

9. The dispersion according to claim 8, characterized in that Component g is selected from one or more of 1,3-bis[(trihydroxymethyl)methylamino]propane, hydroxyethylethylenediamine and isophoronediamine.

10. The dispersion according to any one of claims 1 to 2, characterized in that The raw materials of the dispersion further include one or more of glycerol stearate, sorbitan monostearate, and ethylene glycol distearate, and the addition amount is 1-6 wt %.

11. The dispersion according to any one of claims 1 to 2, characterized in that The solid content of the dispersion is 45-55 wt %, and the particle size of the dispersion is 50-200 nm.

12. A method for preparing a dispersion according to any one of claims 1 to 11, comprising: (1) Components a, b, and c are mixed and reacted to form a prepolymer; (2) adding components d, e, and a catalyst to the prepolymer for chain extension, and cooling after reaching the theoretical NCO%; (3) adding deionized water for dispersion; (4) adding components f and h, and adding component g for chain extension to obtain a waterborne polyurethane dispersion product, The component h is selected from one or more of glycerol stearate, sorbitan monostearate, and ethylene glycol distearate.

13. Use of the dispersion according to any one of claims 1 to 11 or the dispersion prepared by the method according to claim 12, wherein the application field is selected from clothing, shoe materials, and ink.

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