Non-fluoro hydrophobic aqueous-based polyurethane resin dispersion, and production method and use thereof

Abstract

The present invention provides a cross-linking non-fluoro hydrophobic aqueous polyurethane dispersion, which is produced by selecting a compound comprising alcohols, amines, acids, saturated or unsaturated (double-bonded or epoxidized) aliphatic long chain carbon-carbon groups or polydimethylsiloxane comprising alcohol groups, amines, oxosilane to be reacted with IPDI to obtain a PU prepolymer; adding a compound having tertiary amines to neutralize the carboxylic acid of PU prepolymer and adding water to disperse the PU prepolymer; and adding a ambient temperature cross-linking agent to obtain a cross-linking hydrophobic aqueous PU dispersion of the present invention. The hydrophobic aqueous-based PU resin has no fluorine which is friendly to the environment, and may further self cross-links on its applications on fabric, paper, wood, glass and metal surfaces, respectively on drying at ambient temperature which is energy saving process. Its cross-linking reaction of this hydrophobic PU system that will achieve a long-lasting water repellent surface treatment.

Claims

1. A production method of non-fluoro hydrophobic aqueous polyurethane dispersion, which comprises the following steps: mixing and reacting a first compound comprising polydimethylsiloxane and higher alcohol or diols having carbon numbers from 10 to 30 and a second compound having hydrophilic functional groups with a polyisocyanate to obtain a polyurethane prepolymer having at least two isocyanate (NCO) terminal groups, so that hydrophobicity of final polyurethane resins is adjustable by regulating a ratio of the polydimethylsiloxane and the higher alcohol or diols to form a hybridized polyurethane resin; neutralizing the polyurethane prepolymer, then adding water to disperse the polyurethane prepolymer to form an aqueous polyurethane dispersion which are compatible in any ratios; and adding a latent cross-linking agent into a mixture of aqueous polyurethane dispersion to make the aqueous polyurethane dispersion self-crosslinkable.

2. The production method according to claim 1, wherein the latent cross-linking agent is poly-aziridine that reacts with polydimethylsiloxane forming a cross-linked hybridized polyurethane networks.

Description

DESCRIPTION OF FIGURES

(1) FIG. 1 displays a SEM micrograph of the fiber treated by aqueous PU dispersion containing aliphatic acids and PDMS which are mixed and reacted (unwashed);

(2) FIG. 2 displays a EDS of the fiber treated by aqueous PU dispersion containing aliphatic acids and PDMS which are mixed and reacted (unwashed);

(3) FIG. 3 displays a SEM micrograph of the fiber treated by aqueous PU dispersion containing aliphatic acids and PDMS which are mixed and reacted (after 40 washing cycles); and

(4) FIG. 4 displays an EDS of the fiber treated by aqueous PU dispersion containing aliphatic acids and PDMS which are mixed and reacted (after 40 washing cycles) (still have silicon on the surface of fiber).

DETAILS OF THE INVENTION

(5) The present invention is described in details by the following embodiments and figures to clarify the production method for non-fluoro hydrophobic aqueous PU dispersion and the application of water-repellent treatment thereof.

(6) (1) The Preparation of Isocyanate Terminated Polyurethane (PU) Prepolymer

(7) Taking 13.4 g of 2,2-bis(hydroxymethyl) propionic acid (DMPA) and 200 g of polytetramethylene ether glycol (PTMEG-2000) separately and placing them into four-necked reaction tank, and heating to 140 C. to melt DMPA and stirring it with mechanical agitation evenly. Wait for the temperature drop to 50 C., adding 0.1% (w/w) reactive catalyst T-12 and 66.6 g of isophorone diisocyanate (IPDI) and keep reaction temperature below 86 C. with stirring until the reaction is completed (NCO % below the calculated value). After the reaction is completed, processing NCO titration to analyze the degree of reaction, as long as it reaches NCO % is less than 3% and remains at that value for one hour. Further using FT-IR to determine the presence of the NCO peak (near 2267 cm.sup.1) in order to make sure that if the reaction is completed or not. The reaction scheme is as the aforementioned scheme 1.

(8) ##STR00001##

(9) (2) The Preparation of Self-Emulsified Aliphatic Long Chain Carbon-Carbon Bond Containing Aqueous PU Dispersion

(10) Selecting polyether polyol (for instance, PPG or PTMEG), polyisocyanate (IPDI) materials, or diol compounds containing hydrophilic functional groups as internal emulsifier (for instance, dimethylol propanic acid, DMPA) and fatty alcohols (aliphatic long chain carbon-carbon bond alcohol compounds). A long chain carbon-carbon bond containing PU prepolymer having isocyanate as terminal groups (with fatty alcohols involved in the reaction). Determine the amount of NCO to confirm that the reaction is completed, and adding triethylamine to neutralize and adding deionized water and chain extender (such as ethylenediamine) to process the steps of chain extension and dispersion, and the self-emulsified aliphatic long chain carbon-carbon bond containing aqueous PU dispersion is obtained. In this aqueous PU dispersion, adding proper quantity cross-linking agent (TMPTA-AZ or CX100) and maintain the pH value of aqueous PU dispersion system greater than 8.0. The stable self-emulsified aliphatic long chain carbon-carbon bond containing aqueous PU dispersion is formed. The details of the preparation scheme please refer to the following scheme 2.

(11) ##STR00002##

(12) (3) The Preparation of Room-Temperature Cross-Linked Single-Liquid Non-Fluoro Hydrophobic Aliphatic Acid (Ester)-Contained Aqueous PU Dispersion

(13) Selecting polyether polyol (PPG or PTMEG), polyisocyanate (IPDI) materials, or diol compounds containing hydrophilic functional groups as internal emulsifier (DMPA) and high carbon-carbon aliphatic acid compounds to process PU resin. A long chain fatty acid containing PU prepolymer having isocyanate as terminal-ended group (with hydroxyl or epoxidized fatty acid involved in the reaction). This aliphatic PU prepolymer having isocyanate (NCO) as terminal-ended group, and adding aliphatic acids (as stearic acid, oleic acid, epoxidized oleic acid or ricinoleic acid) alone or proper ratio separately in PU prepolymer. Then adding triethylamine to neutralize and adding deionized water and chain extender (such as ethylene diamine) to process the steps of chain extension and dispersion (aliphatic fatty acid becomes soap after neutralization which have emulsified efficacy), and the self-emulsified aliphatic soap-containing aqueous-based PU dispersions is obtained. In this aqueous PU dispersion, adding proper quantity latent cross-linking agent (TMPTA-AZ or CX100) and maintain the pH value of aqueous PU dispersion more than 8.0. The stable self-emulsified fatty acid-containing aqueous PU dispersion is formed.

(14) (4) The Preparation of Room-Temperature Cross-Linked Single-Liquid Non-Fluoro Hydrophobic Polydimethylsiloxane-Contained Aqueous PU Dispersion

(15) Selecting polyether polyol (PPG or PTMEG), polyisocyante (IPDI) materials, or diol compounds containing hydrophilic functional groups as internal emulsifier (DMPA) and polydimethylsiloxane(PDMS)-containing diol are added to process PU resin. The PDMS-containing PU prepolymer having isocyanate as terminal-ended group, and then adding triethylamine to neutralize and adding deionized water and chain extender (such as ethylene diamine) to process the steps of chain extension and dispersion, and self-emulsified polydimethylsiloxane-containing aqueous PU dispersion is obtained. The details of the preparation scheme please refer to the following scheme 3.

(16) ##STR00003##

(17) (5) The Room-Temperature Cross-Linking Reaction of Single-Liquid Non-Fluoro Hydrophobic Aqueous PU Dispersion

(18) Regarding the single-component hydrophobic aqueous PU dispersion of the present invention, the fatty (alcohol or acid) or polydimethylsiloxane (PDMS)-containing aqueous PU dispersion is introduced carboxylic acid group (COOH) separately. After neutralization and dispersion by adding water under a high speed mechanical mixing, the ionic group (carboxyl groups COO) induced is used as internal emulsifier to provide the stability of aqueous PU dispersion. The latent cross-linking agent containing aziridine functional groups (as TMPTA-AZ or CX-100) added into single-liquid non-fluoro hydrophobic aqueous PU dispersion would react with carboxyl groups in PU resin to process open-ring cross-linking reaction under room temperature being dried at ambient temperature. It would react with hydrophilic carboxyl groups and form hydrophobic amino ester bonding, and improve the cross-linking density of aqueous PU resin on drying. The water resistance, solvent resistance, mechanical strength and heat stability would be improved accordingly. Due to the aziridine functional groups contained in aqueous PU as a latent cross-linking agent having high pH value, aziridine can present in water dispersion stably. When under low pH value (<7.0), aziridine would process open-ring reaction with carboxylic acid (COOH) in PU resin or process open-ring reaction itself under room temperature without heating or other energy (the radiation of UV). The details of the cross-linking (curing) reaction please refer to the following scheme 4.

(19) ##STR00004##

(20) (6) The Treatment of Water-Repellent Coating

(21) The aqueous PU dispersion containing different amount of polydimethylsiloxane (PDMS) or aliphatic acid or fatty alcohol is coated by a simple method (scraper, roller, impregnation, spray or screen printing and the like) to process the treatment of water-repellent on the surface of fabric. Under the condition of room temperature, the self-curing (cross-linking) reaction is carried out to form PU resin with interpenetrating networks (IPN) structure tightly and anchored between longitudinal yarn and latitudinal yarn of the fabric, so that it improve the durability of water washing of water-repellent resin treated fabric. After the washing test of National Standard AATCC135-2004 to wash it for 40 cycles, it still remains 85% of the original water-repellent efficacy. This kind of water-repellent PU resin requires only small amount (5-15% solid contents) for coating to achieve water-repellent efficacy.

(22) The present invention is clarified by preferable specific embodiments which are not used to limit the present invention.

(23) The synthesis and preparation of self-emulsified aliphatic long chain carbon-carbon bond containing aqueous PU dispersions

(24) Using different polyols of polymer and polyisocyanates materials, diol compounds containing hydrophilic functional groups as internal emulsifier (such as ionic internal emulsifier and non-ionic internal emulsifier) and fatty alcohol of long chain carbon-carbon aliphatic alcohols compounds to process addition polymerization reaction by different formulating method. The aliphatic long chain carbon-carbon PU oligomer and prepolymer used isocyanate as terminal-ended groups are formed. Further neutralization by a tertiary amine deionized water and chain extender to process the steps of chain extension and water dispersion with mechanical agitation. It results in a formation of self-emulsified aliphatic carbon-carbon chain containing aqueous-based PU dispersions.

(25) The materials which are needed to synthesize self-emulsified aliphatic carbon-carbon chain containing aqueous-based PU dispersions are listed as following:

(26) 1. Polyols

(27) The property of polyurethane elastomers is due to the chain structure having flexibility and the structure of minor branching or partial net cross-linking. Polyols with better flexibility are polyesters, polyethers, polyether-ester polyols or polyester-amide polyols and the like.

(28) (a) Polyester Polyols:

(29) ##STR00005##
(b) Polyether Polyols (PP): The common polyether polyols are as following: polyethylene glycols, polypropylene glycols, polytetramethylene glycols which have the average molecular weight ranging in 400-4000.
2. Polyisocyanates

(30) The most common diisocyante is toluene diisocyanates (TDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4-methylene diphenyl diisocyanate (MDI) and the like. In aromatic diisocyanates, the main toluene diisocyanates in the market comprise: 80% of 2,4-toluene diisocyanates (TDI) and 20% of 2,6-toluene diisocyanates (TDI). In the 2,4-toluene diisocyanates molecule, the activity of para-(4-) isocyanate functional groups is higher than ortho-(2-,6-) ones by 4 to 5 times. It benefits for producing selective isocyanate prepolymer.

(31) In addition, in aliphatic diisocyanates, two isocyanate functional groups in isophorone diisocyanate (IPDI) show different activity. Without the influence of catalyst, secondary isocyanate functional groups (2-NCO) have higher reaction rate than the one of primary isocyanate functional groups (1-NCO). Surprisingly, after adding minor tin catalyst, secondary isocyanate functional groups (2-NCO) have higher reaction rate than the one of primary isocyanate functional groups (1-NCO) by 11 to 15 times, which is a dominant advantage. Using the selective isocyanate functional groups in steps of producing polyurethane prepolymer, it benefits for easy operation in producing procedures and the isocyanate prepolymer generated is valuable.

(32) 3. Triols cross-linking agent: Glycerol, Trimethylolpropane (TMP), 1,2,6-Hexanetriol, Triethanolamine (TEA) and the like.

(33) ##STR00006##
4. Ionic Center, such as dimethylolpropanic acid (DMPA), Dimethylolbutanoic acid (DMBA)
5. Aqueous PU ambient temperature cross-linking (curing) agent:

(34) The aliphatic long chain carbon-carbon bond containing-PU oligomer and prepolymer is obtained from a process of the addition polymerization of polyols, polyisocyanates and ionic center (as an internal emulsifier, DMPA). Then proceed a process of neutralization with trialkylamine (e.g. triethylamine, TEA), and chain-extension with ethylenediamine during water dispersion. The internal ionic center within PU resin that having stable micelles of PU particles formation that suspends in the aqueous PU dispersion. The latent PU cross-linking agent is added into the aqueous dispersion and it results in the formation of stable cross-linking single-component aliphatic long chain carbon-carbon bond containing aqueous PU dispersion (its pH value>8.0). The cross-linking reaction takes place during drying process at ambient temperature or the pH value drops below 7.0.

(35) This cross-linked PU resin owns the physical and chemical properties of water resistance, solvent resistance, mechanical strength and heat stability would be improved in large scale accordingly. By improving the cross-linking density to enhance the polymeric network structure of PU resin. This latent cross-linking agent (such as TMPTA-AZ) could be triggered the ring-opening reaction self-curing by lowering its pH value of resin system. It is a convenient (single component), energy saving (at ambient temperature) cross-linking reaction takes place immediately when the pH value of PU system lowers than 7.0. The common ambient temperature cross-linking agents are listed as following:

(36) ##STR00007##
6. Aliphatic alcohols and aliphatic acids of long chain aliphatic compounds:
[1] Octanol, C8, [2] 1-Nonanol, C9, [3] 1-Decanol, C10, [4] Undecanol, C11, [5] Dodecanol, C12, [6] 1-Tetradecanol, C14, [7] Cetyl alcohol, C16, [8] Stearyl alcohol, C18, [9] Arachidyl alcohol, C20, [10] Docosanol, C22, [11] Octanosol, C28, [12] Triacontanol, C30, [13] Policosanol, Cn
Aliphatic Acids
[1] Oleic acid, C18, [2] Ricinoleic acid, C18, [3] 12-Hydroxystearic acid, C18), [4] epoxidized oleic acid, C18

(37) ##STR00008##

Example 1: The Preparation of Isocyanate Terminated Polyurethane (PU) Prepolymer

(38) Taking 13.4 g of 2,2-bis(hydroxymethyl) propionic acid (DMPA) and 200 g of polytetramethylene ether glycol (PTMEG-2000) separately and placing them into four-necked reaction tank, and heating to 140 C. to melt DMPA and stirring it with mechanical agitation evenly. Wait for the temperature drop to 80 C., adding 0.1% (w/w) catalyst (T-12) and 66.6 g of isophorone diisocyanate (IPDI) and keep reaction temperature below 86 C. with stirring until the reaction is completed (NCO % below the calculated value). After the reaction is completed, processing NCO titration to analyze the degree of reaction, as long as it reaches NCO % is less than 3% and remains at that value for one hour. Further using FT-IR to determine the presence of the NCO peak (near 2267 cm.sup.1) in order to make sure that if the reaction is completed.

Example 2: Preparing Aliphatic Long Chain Carbon-Carbon Bond Containing PU Oligomer

(39) Using isocyanate functional groups having selective diisocyantes (polyisocyantes, IPDI)), triol (glycerol or trimethylolpropane, TMP) and long chain fatty alcohol compounds (fatty alcohol or higher alcohol), by using an excess amount of isocyanates (IPDI), and then adding minor catalyst, dibutyltin dilaurate (DBTDL) to accelerate the reaction being completed. It results in the formation of NCO-terminated aliphatic long chain carbon-carbon bond containing PU oligomer.

Example 3: The Preparation of Single-Component Aliphatic Long Chain Carbon-Carbon Bond Containing Aqueous PU Dispersion

(40) Selecting polyether polyol (e.g., PPG or PTMEG), polyisocyanate (IPDI) materials, or diol compounds containing hydrophilic functional groups as internal emulsifier (for instance, dimethylol propanic acid, DMPA) and fatty alcohols (aliphatic long chain carbon-carbon bond alcohol compounds). A long chain carbon-carbon bond containing PU prepolymer having isocyanate as terminal group (with fatty alcohols involved in the reaction). Determine the amount of NCO to confirm that the reaction is completed, and adding triethylamine to neutralize and adding deionized water with a chain extender (such as diethyleneamine) to process the steps of chain extension and dispersion, and the self-emulsified aliphatic-containing aqueous PU dispersions is obtained. In this aqueous PU dispersion, adding proper quantity latent cross-linking agent (TMPTA-AZ or CX100) and maintain the pH value (>8.0) of aqueous PU dispersion. The stable single-component cross-linking aliphatic long chain carbon-carbon bond containing aqueous PU dispersion is formed.

Example 4: The Preparation of Self-Emulsified PDMS-Containing Aqueous PU Dispersion

(41) Taking 180 g of polydimethylsiloxane (PDMS)diol (for instance, KF-6001) and 13.4 g of dimethylol propanic acid (DMPA, an internal ionic center) separately and placing them into four-necked reaction flask, and heating to 140 C. to melt DMPA under vacuum and with constant mechanical agitation for 4 hours. After cooling down to 50 C., then 0.2 g of catalyst (T-12) and 66.6 g of Isophorone diisocyanate (IPDI) are added into PDMS diol with agitation and keep the reaction temperature below 86 C. until the reaction is completed (NCO % below the calculated value). It results in a formation of PDMS-containing PU prepolymer having isocyanate as terminal groups. An aqueous mixture of de-ionized water of neutralizing agent (triethylamine, TEA) and chain-extender (ethylene diamine) is added into this PDMS-prepolymer slowly with agitation and self-emulsified PDMS-containing aqueous PU dispersion is obtained.

Example 5: Cross-Linking PDMS/Oleic Containing Hydridizied PU Dispersions

(42) The ratio of PDMS containing aqueous PU dispersion with oleic soap (oleic acid amine soap) (PDMS/oleic) with 2/1, 1/1 and 1/2, are selected and mixing separately. Then TMPTA-AZ, a latent cross-linking agent (3 phr) is added into each mixture as latent cross-linking agent. Each becomes cross-linking PDMS/oleic containing hydridizied PU dispersions. After drying at ambient temperature, it results in the formation of cross-linked PDMS/oleic containing hybridized PU resin. Both PDMS and oleic acid are chemical bonded with hydrophobic PU resin. The dried cross-linking PDMS/oleic hybridized hydrophobic PU resin is shown as the following scheme 5.

(43) Mixing PU/oleic acid mixed aqueous dispersion and aqueous PDMS-PU dispersion which are obtained from synthesis reaction by the ratio of 2:1, 1:1 and 1:2, and then adding TMPTA-AZ cross-linking agent. The dried cross-linking scheme is shown as the following scheme 5.

(44) ##STR00009##

Example 6: The Water-Repellent Treatment of Fiber for Room-Temperature Cross-Linking Oleic Acid-Contained and Polydimethylsiloxane(PDMS) Contained Mixing Aqueous Dispersion

(45) Following Example 5, diluting the cross-linking PDMS/oleic containing hybridized PU dispersion with de-ionized water to proper concentration (5-10% of solid). Then apply it on the surface of fabric to carry out the hydrophobic treatment. It is cross-linked and forming interpenetrating polymeric network (IPN) structures and anchored into fabric after drying. That improves the bonding strength between treated PU resin and fabric that improve washing durability and solvent resistance of hydrophobic treated fabrics.

(46) Please refer to Table 1. Shown as the SEM micrographs (FIG. 1 and FIG. 3) and EDS (FIG. 2 and FIG. 4), it proves that the treatment on the surface of fabric by the cross-linked PDMS/oleic containing hybridized PU resin of the present invention can maintain over 85% original hydrophobic property (water-repellent efficacy) after 40 washing cycles, furthermore, it is found that there are silicon of PDMS stays on the surface of fabric (EDS).

(47) TABLE-US-00001 TABLE 1 The hydrophobic property of the fiber surface treated by aqueous PU dispersion containing aliphatic acid and PDMS mixed (washed 40 times) PDMS/oleic ratio of hybridized PU resin 2/1 1/1 1/2 Water drop contact angle on 125.0 128.3 135.3 treated fabrics () Sliding angle of water drops () 18.8 17.8 17.8 on treated fabric surface Time for water drops stay on >60 >60 >60 treated fabrics (min)
To sum up the aforementioned description, the non-fluoro hydrophobic PDMS/oleic containing hybridized PU (polyurethane) resin of the present invention can have long lasting hydrophobic property after 40 washing cycles of treated fabrics. By cross-linking reaction to improve the cross-linking density of hydrophobic PDMS/oleic containing hybridized PU resin of the present invention, it has improved the property of washing durability (resistance) and solvent resistance. Besides, the PU resin of the present invention has no fluoro and the water repellent treatment with less energy requirement which comply with the non-toxic requirements and provision of components used in fabrics in the future to people nowadays. The present invention comparing to prior water repellent which uses fluoro compounds has superior efficacy.