KR102623746B1 - Method for producing high solids water-dispersible polyurethane with excellent hydrolysis resistance - Google Patents

Abstract

The present invention relates to a method for producing high-solids water-dispersed polyurethane with excellent hydrolysis resistance, comprising the steps of dissolving polymeric polyol by placing polymeric polyol and solvent in a reactor and stirring to dissolve the polymeric polyol; A prepolymer forming step of adding diisocyanate to the polymeric polyol to form a polyurethane prepolymer; And a chain extension step of adding a chain extender to the polyurethane prepolymer to extend the chain containing the polymeric polyol and the diisocyanate to produce a water-dispersed polyurethane resin. do. As a result, it is possible to produce a suede fabric with excellent flame retardancy by coating it with a high-solids water-dispersed resin with excellent flame retardancy.

Description

Method for producing high solids water-dispersible polyurethane with excellent hydrolysis resistance}

The present invention relates to a method for manufacturing high-solids water-dispersed polyurethane with excellent hydrolysis resistance. More specifically, the present invention relates to a method of manufacturing a high-solids water-dispersed polyurethane with excellent flame retardancy, and more specifically, a high-solids water-dispersed polyurethane with excellent hydrolysis resistance that can be coated with a high-solids water-dispersed resin with excellent flame retardancy to produce a suede fabric with excellent flame retardancy. It relates to a method for manufacturing high-solids water-dispersed polyurethane.

Currently, the most widely used suede artificial leather material is synthetic/artificial leather material using solvent-based polyurethane (PU), which not only has excellent physical properties required for a film such as abrasion resistance and bending resistance, but also provides adhesive properties. , it has the advantage of excellent appearance characteristics. However, in order to manufacture polyurethane synthetic/artificial leather materials, solvents designated as carcinogens such as dimethylformamide (DMF), methyl ethyl ketone (MEK), and toluene are used. There is a problem that it acts as an environmental hazard and its use is restricted by global environmental regulations as the industrial environment changes. In addition, the above-mentioned solvents have a problem in that they are highly volatile and are a major cause of fires in the workplace.

Therefore, in order to respond to strengthening regulations, related industries are developing water-dispersed polyurethane that can replace solvent-based polyurethane. However, when water-dispersed polyurethane resin is processed into fabric, the resin migrates to the yarn. It has the disadvantage of becoming hard to the touch, reducing elasticity, and causing wrinkles in the fabric. To solve this problem, a foam dipping process is used, but it has the disadvantage that swelling occurs in the water-dispersed polyurethane resin and it cannot be uniformly applied to the fabric, so technology to improve this is needed. This is the situation. In other words, the touch of the water-dispersed polyurethane resin is improved and a water-dispersed polyurethane resin for impregnation is needed for use in suede production. In order to manufacture this, it is necessary to improve the water-dispersed polyurethane resin with improved hydrolysis resistance. .

In addition, suede fabric used as vehicle interior material using water-dispersed polyurethane resin is coated to improve touch and aesthetics, and is generally coated with polyurethane resin. However, when coating suede fabric using polyurethane resin, there are problems in the manufacturing process because excessive amounts of organic solvents are used during the coating step, and there are problems with residual hazardous substances (VOCs) being detected when organic solvents are used. This limits the application of automobile interior materials, and also causes passenger safety issues and environmental issues at the time of disposal due to the generation of hydrogen cyanide gas, a toxic gas, during combustion.

In order to solve this problem, water-dispersed polyurethane resin is used and suede fabric is coated. However, when water-dispersed polyurethane resin is used, there is a problem that the mechanical properties of the fabric deteriorate as mentioned above.

Korea Intellectual Property Office Registered Patent No. 10-0526171

The present invention was developed to solve the above problems, and provides a method for manufacturing high-solids water-dispersed polyurethane with excellent hydrolysis resistance that can produce suede fabric with excellent flame retardancy by coating a high-solids water-dispersed resin with excellent flame retardancy. It is provided.

The above purpose includes a polymeric polyol dissolution step of dissolving the polymeric polyol by placing polymeric polyol and a solvent in a reactor and stirring; A prepolymer forming step of adding diisocyanate to the polymeric polyol to form a polyurethane prepolymer; And a chain extension step of adding a chain extender to the polyurethane prepolymer to extend the chain containing the polymeric polyol and the diisocyanate to produce a water-dispersed polyurethane resin. This is achieved through a high-solids water-dispersed polyurethane production method with excellent hydrolysis resistance.

Here, the polymeric polyol is selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, polyacryl polyol, and mixtures thereof, and has a molecular weight of It is preferable that it consists of 200 to 10,000 Mw.

In addition, the diisocyanate is aromatic diisocyanate or aliphatic diisocyanate, and the aromatic diisocyanate is para-phenylene diisocyanate (PPDI) 4,4-methylenediphenyl diisocyanate. Isocyanate (4,4-methylene diphenyl diisocyanate, MDI), toluene diisocyanate (TDI), 1,5-naphthalene diisocyanate (NDI), xylene diisocyanate (XDI) and mixtures thereof, wherein the aliphatic diisocyanate includes 1,4-cyclohexyl diisocyanate (CHDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate ( isophoron diisocyanate (IPDI), dicyclohexylmethane-4,4 diisocyanate (H ₁₂ MDI, hydrogenated MDI, HMDI), 1,3-bisisocyanatomethylcyclohexane (1,3 -Bis(Isocyanatomethyl)Cyclohexane, H ₆

As described above, according to the present invention, it is possible to produce a suede fabric with excellent flame retardancy by coating a high-solids water-dispersed resin with excellent flame retardancy.

1 is a flowchart of a method for producing water-dispersed polyurethane according to an embodiment of the present invention,
Figure 2 is a table showing the content of each ingredient corresponding to various examples,
Figure 3 is data showing infrared spectroscopic analysis of the water-dispersed polyurethane resin prepared through each example,
Figure 4 shows experimental data on alkali reduction for each example,
Figure 5 shows data from experiments on hydrolysis resistance for each example.

Hereinafter, the technical idea of the present invention will be described in more detail using the attached drawings. The attached drawings are merely examples to illustrate the technical idea of the present invention in more detail, so the technical idea of the present invention is not limited to the form of the attached drawings.

Figure 1 is a flowchart of a method for producing water-dispersed polyurethane according to an embodiment of the present invention, Figure 2 is a table showing the content of each component corresponding to various examples, and Figure 3 is a water dispersion prepared through each example. This is data showing infrared spectral analysis of polyurethane resin, Figure 4 is data showing alkali loss tested for each example, and Figure 5 is data showing hydrolysis resistance tested for each example.

The present invention adjusts the hydroxide/isocyanate (OH/NCO) molar ratio composition of the high-solids water-dispersed polyurethane (PU) resin and minimizes the amount of ionomer used, which provides dispersibility by making it ionic. The purpose is to improve the disadvantage of deteriorating mechanical properties. Here, an ionomer refers to a polymer whose molecular chain is bridged by ionic bonds. Typically, ionomers obtained from a copolymer of unsaturated carboxylic acid and ethene or a copolymer of methacrylic acid and butadiene are widely used commercially.

In addition, the purpose of the present invention is to produce a water-dispersible polyurethane resin that is environmentally friendly and can improve hydrolysis resistance by using isocyanate (NCO), a hydrocarbon with excellent water resistance.

The method for producing high-solids water-dispersed polyurethane with excellent hydrolysis resistance according to the present invention includes a polymeric polyol dissolving step (S100), a prepolymer forming step (S200), and a chain extension step (S300), as shown in FIG. do.

First, the polymeric polyol dissolution step (S100) refers to the step of dissolving the polymeric polyol in the solvent by putting an appropriate amount of polymeric polyol and solvent into the reactor and stirring.

The polymeric polyol used in the production of water-dispersed polyurethane resin consists of polyether polyol, polyester polyol, polycarbonate polyol, polyacryl polyol, and mixtures thereof. It is preferred that it is selected from the group. In addition, it is preferable to use a polymeric polyol having a molecular weight of 200 to 10,000 Mw. As the molecular weight of the polymeric polyol used increases, the flexibility of the polyurethane resin increases.

Table 1 below shows the composition and characteristics of the polymeric polyol applicable to the present invention, and among these compositions, the component ratio can be appropriately adjusted to obtain a polyurethane resin with desired physical properties. Here, PEG means polyethylene glycol (PEG), PPG means polypropylene glycol (PPG), and PTMG means polytetramethylene ether glycol.

polyol characteristic constitutional formula polyether polyol PEG, PPG PEG has low water resistance, so it is used copolymerized with PPG rather than alone. It has excellent cold resistance and is inexpensive. PTMG It has excellent cold resistance and hydrolysis resistance, and as an expensive product, it has high physical properties and excellent workability. polyester polyol It has low viscosity and has excellent heat resistance, hydrolysis resistance, and low temperature characteristics. polycarbonate polyol It has the best physical properties and exhibits the best physical properties compared to other polyols.

The solvent is a mixture of water and acetone to produce a water-dispersed polyurethane resin. The mixed solvent of water and acetone is dimethylformamide (DMF), which is used to produce conventional polyurethane resins. Because it is a non-toxic solvent, unlike solvents that are classified as carcinogens such as methyl ethyl ketone (MEK) and toluene, the safety of workers manufacturing water-dispersed polyurethane resin can be guaranteed.

The prepolymer forming step (S200) refers to the step of adding diisocyanate to polymeric polyol to form a polyurethane prepolymer.

Through the polymeric polyol dissolution step (S100), diisocyanate is continuously added to the polymeric polyol dissolved in the solvent to form a polyurethane prepolymer. Here, diisocyanate (OCN-R-NCO) refers to a composition containing two isocyanate groups at both ends.

In general, diisocyanate can be divided into aromatic diisocyanate and aliphatic diisocyanate. For aromatic diisocyanate, para-phenylene diisocyanate (PPDI), 4,4-methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), 1, It is selected from the group consisting of 5-naphthalene diisocyanate (NDI), xylene diisocyanate (XDI), and mixtures thereof, and in the case of aliphatic diisocyanate, 1,4-cyclohexyl diisocyanate (1 , 4-cyclohexyl diisocyanate, CHDI) hexamethylene diisocyanate (HDI), isophoron diisocyanate (IPDI), dicyclohexylmethane-4,4 diisocyanate (H) ₁₂ MDI, hydrogenated MDI, HMDI), 1,3-bis(Isocyanatomethyl)Cyclohexane (1,3-Bis(Isocyanatomethyl)Cyclohexane, H ₆ It is desirable, but not limited to this.

Most diisocyanates used in the production of polyurethane resins are aromatic diisocyanates, which are more reactive than aliphatic diisocyanates. Among these, TDI or MDI are mainly used. Since the mid-1980s, the demand for MDI has greatly surpassed the demand for TDI. there is. In addition, aliphatic diisocyanate is mainly used to manufacture non-yellowing type polyurethane resin, and the trend of its use is gradually increasing. Meanwhile, diisocyanates have double bonds, so addition reactions occur, and their reactivity is greatly affected by steric hindrance, substituents, catalysts, etc.

Table 2 below shows the relative ratios of reactivity of various diisocyanates, and Table 3 shows the physical properties of diisocyanates.

diisocyanate reactivity PPDI 1.85 NDI 1.37 MDI One CHDI 0.28 IPDI 0.15 HMDI 0.13

Molecular Weight importance refractive index Viscosity (cps) Solidifying point (℃) Flash point (℃) TDI 174.16 1.22 1.5663 3 11.5~13.5 132 MDI 250.26 1.19 - solid 37~38 202 polymeric
MDI 360~400 1.2 - 100 or more - 200 or more NDI 210.2 1.42 1.4253 solid 120~130 155 XDI 188.2 1.2 - 3.6
(20℃) - 185 H ₁₆ MDI 194.2 1.1 - 5.8
(25℃) about -50 150 IPDI 222.28 1.06 1.4829 15
(20℃) about -60 163 HDI 168.2 1.04 1.4516 25
(20℃) About -67 140 H ₁₂ MDI 262 1.07 - 29
(25℃) 10~15 201

The chain extension step (S300) refers to the step of producing a water-dispersed polyurethane resin by adding a chain extender to the polyurethane prepolymer to extend the chain containing polymeric polyol and diisocyanate.

A chain extender is intermittently added to the polyurethane prepolymer containing polymeric polyol and diisocyanate in several portions. The polymeric polyol and diisocyanate form a chain through the chain extender, and the chain extender is added several times to form a chain. This is extended to produce a water-dispersed polyurethane resin. At this time, while the chain extender is intermittently added, diisocyanate is present in excess, but when the chain extender is finally added, the diisocyanate completely disappears as the water-dispersed polyurethane resin reaches an appropriate viscosity. Afterwards, appropriate solvents and additives are added to suit the intended use, and the reaction is completed.

Here, diol is used as the chain extender, and these diols include ethylene glycol, diethylene glycol, 1,2-propanediol, 1 ,3-propanediol, neopentanediol, 1,4-butanediol, 1,5-pentanediol, 1,6 -It is preferably selected from the group consisting of hexanediol (1,6-hexanediol) and mixtures thereof, but is not limited thereto.

In this way, the water-dispersed polyurethane resin manufactured through the polymeric polyol dissolution step (S100), prepolymer formation step (S200), and chain extension step (S300) not only has excellent hydrolysis resistance but also has a high solid content, so it can be used on suede fabric. When applied, the flame retardancy of suede fabric can be improved.

In the present invention, a high solid polyurethane resin was prepared as in Example 1 to improve the physical properties of the water-dispersed polyurethane resin for artificial leather impregnation and to improve the filling of the fabric after impregnation, and the produced polyurethane The physical properties of the resin were analyzed.

<Example 1>

For the polymerization of high-solids polyurethane resin, polyester polyol polytetramethylene ether glycol (PTMG) was used as the polyol, as shown in Table 4, and the chain extender was 1,4-butanediol and diol. Isocyanate used was isophoron diisocyanate (IPDI) and dicyclohexylmethane-4,4 diisocyanate (H ₁₂ MDI). For the synthesis of high-solids polyurethane resin, the solids content was designed to be 40% and the synthesis was carried out, and the molecular weight and properties of the composition used in Example 1 can be confirmed through Table 4.

division Raw material Molecular Weight manufacturing company polyol PTMG 1,000~2,000 Aldrich diol 1,4-Butanediol 90.12 Aldrich isocyanate IPDI 222.28 Aldrich H ₁₂ MDI 262 Aldrich catalyst DBTDL - Aldrich solvent acetone - domestically produced water - Distilled water chain extender EDAs
(ethylene diamine) 60.1 Aldrich

In the step of polymerizing the polyurethane resin, first, a prepolymer having isocyanate at both ends is prepared. The manufacturing method involves maintaining a 500ml 4-neck resin kettle equipped with a mechanical stirrer, condenser, and nitrogen gas (N ₂ Gas) inlet at a constant temperature using an oil bath, and then blowing dried nitrogen. ) to create a nitrogen atmosphere inside the kettle.

Next, the temperature inside the reactor was maintained at 80°C, a set amount of IPDI and PTMG were added and stirred, and the isocyanate was metered at regular intervals. When the appropriate NCO% was reached, dimethyl propionic acid (DMPA), which has a hydrophilic group, was added. It was put in.

Afterwards, when the viscosity of the reactant rapidly increased, the temperature was lowered to 40°C and a small amount of acetone was added to dissolve it. After reacting for more than an hour, a neutralizing agent was added and neutralized for 2 hours to prepare an ionized prepolymer. In order to disperse the prepared prepolymer in water, distilled water was added dropwise to the dropping funnel while rotating the stirrer at high speed.

Next, polyurethane resin was synthesized by extending the chain with a diol or diamine-based chain extender. After confirming the isocyanate absorption peak using infrared spectroscopy (FT-IR), the chain extender was added dropwise with distilled water, and the experiment was terminated after the isocyanate absorption peak completely disappeared, resulting in high-solids polyurethane with a final solid content of more than 40wt%. (High Solid PU) resin was synthesized. In the input amount, the ratio of isocyanate/hydroxide (NCO/OH) was fixed at 1.0, and the molar ratio of PTMG and DMPA was varied from 0.33 to 0.5/0.67 to 0.5. Figure 2 shows the component contents in various examples with different component ratios of each component, and Figure 3 shows infrared spectroscopic analysis (FT-IR) of the water-dispersed polyurethane resin prepared through each example. The solid content of the high-solids polyurethane resin prepared in this way can be confirmed through Table 5.

Solid content (%) PUD 3 42.21 PHSA-2 37.98 PHSA-3 38.72 PHSA-4 37.52 PHSA-5 39.49 PHSA-6 36.28

Figure 4 shows the alkali loss experiment for each example, and shows the results of measuring the loss rate and change in tensile strength after treatment with NaOH 5.0% soln. (100°C, 10 min). Figure 5 shows the hydrolysis resistance test and corresponds to the results of measuring the weight change and tensile strength change after treatment with water (100°C, 30 min).

Polyurethane resin is widely used as an impregnation agent for artificial leather among other uses, and this originates from the desire to imitate the structure of natural leather. Natural leather expresses different emotions due to differences in the three-dimensional fiber bundle network structure and non-collagen content, and has excellent volume and a soft touch due to the natural density gradient of the fiber bundle. In addition, natural leather exhibits unique properties such as rebound elasticity and elasticity due to elastin fibers intertwined between collagen fiber bundles and lipids deposited between them. Among synthetic polymers, polyurethane resin exhibits similar properties. Artificial leather is mainly manufactured in the form of knitted fabric, woven fabric, or non-woven fabric using polyethylene terephthalate (PET) yarns whose cross-sectional thickness is ultra-fine to 5㎛ in order to reproduce natural sensibility, and polyurethane resin is used to fabricate the fabric. A network structure is formed inside to reproduce natural volume and elasticity.

Polyurethane resins used as impregnation agents for artificial leather have traditionally been manufactured using organic solvents due to the strong hydrophobicity of polyol. However, as interest in environmental issues increases both domestically and internationally, organic solvents such as dimethylformamide (DMF), methyl ethyl ketone (MEK), and toluene, which are used in organic solvent-based polyurethane, are increasing in environmental risk. Regulations are being strengthened as it causes pollution and has fatal effects on the body. Accordingly, water dispersion polyurethane (WPU) resin, which uses water as a solvent, is being replaced to the extent that it does not cause environmental pollution. Like solvent-based polyurethane resins, these water-dispersed polyurethane resins exhibit various morphologies due to the phase separation phenomenon, and various physical properties are possible depending on the chemical structure of the main chain, such as flexibility and toughness as well as chemical resistance, solvent resistance, and abrasion resistance. Physical properties such as the like can also be controlled relatively easily. However, the water-dispersed polyurethane resin used as an impregnation processing agent for artificial leather has inferior physical properties such as processability, coating properties, elasticity, and rebound elasticity compared to solvent-based polyurethane resin, and has the disadvantage of poor friction durability, water resistance, and weather resistance of the final product. Therefore, it is still used for limited purposes.

In order to solve this problem, the present invention proposes a method for manufacturing high-solids water-dispersed polyurethane with excellent hydrolysis resistance that can produce suede fabric with excellent flame retardancy by coating a high-solids water-dispersed resin with excellent flame retardancy. It can be confirmed through experiments that the effect on flame retardancy is excellent.

The present invention is not limited to the above-described embodiments, and the scope of application is diverse. Of course, various modifications and implementations are possible without departing from the gist of the present invention as claimed in the claims.

S100: polymeric polyol dissolution step
S200: Prepolymer formation step
S300: Chain extension step

Claims (3)

A polymeric polyol dissolution step of dissolving the polymeric polyol by placing 0.04 mole (mol) of polymeric polyol, which is 1,000 Mw polytetramethylene ether glycol (PTMG), and a solvent into a reactor and stirring;
A prepolymer forming step of forming a polyurethane prepolymer by adding 0.15 mole of diisocyanate, which is dicyclohexylmethane-4,4 diisocyanate (H ₁₂ MDI), to the polymeric polyol; and
To the polyurethane prepolymer, 0.00425 mol of ethylenediamine (EDA) and 0.05175 mol of 1,4-butanediol (1,4-BD) were added as chain extenders to form a chain containing the polymeric polyol and the diisocyanate. A method for producing a high-solids water-dispersed polyurethane with excellent hydrolysis resistance, comprising a chain extension step of producing a water-dispersed polyurethane resin by extending the chain. delete delete