KR20090085805A - Preparation method of high solid and low ionic content waterborne polyurethanes - Google Patents

Abstract

A water-dispersible polyurethane resin is provided to ensure low anion content and high particle stability, to perform water dispersion of solid portion, and to be various industrial uses such as paint adhesive, fiber-treating agent and primer. A method for manufacturing a water-dispersible polyurethane resin comprises the steps of: reacting a chain extender and a diisocyanate compound in a weight ratio of 1 : 2.5~3 to manufacture isocyanate-terminated hard segments; reacting the hard segments 100.0 parts by weight, polyol 295~310 parts by weight and diisocyanate compound 65~80 parts by weight to manufacture a hydroxyl group-terminated prepolymer I containing soft segments; reacting the prepolymer I 100.0 parts by weight, diol 2~3 parts by weight having a carboxyl group and a diisocyanate compound 2~4 parts by weight to manufacture a prepolymer II; and preparing the water-dispersible polyurethane resin by water-dispersing the prepolymer II.

Description

Preparation Method of Dispersed Polyurethane Resin with Low Ion Content and High Solid Content {Preparation Method of High Solid and Low Ionic Content Waterborne Polyurethanes}

The present invention relates to a method for preparing a water-dispersed polyurethane having a high solids content by using a low content of anion center by placing an ion center at a soft segment end, wherein the water-dispersed polyurethane prepared by the above method is dried. Speed, hydrolysis stability and so on.

Conventional solvent-type polyurethanes are limited in many countries due to fire hazards and environmental regulations in conventional applications. Therefore, due to the recognition and regulation of environmental pollution and the steady increase in the price of solvent, the situation is gradually converted to water-dispersed polyurethane.

Compared with the conventional solvent-type polyurethane, the water-dispersed polyurethane has insufficient drying speed, storage stability, adhesive strength and mechanical properties, and particularly, due to anion centers that are inevitably introduced for water dispersion, drying speed, storage stability, adhesive strength, and the like. There is a disadvantage that the physical properties such as mechanical properties are significantly reduced, there is a problem that the use range is very limited. In order to solve this problem, the present invention is limited to a method of improving the hydrolysis resistance of a resin by various methods such as introducing or hybridizing other materials such as nano clay, glass fiber, silica particles, and the like into the polyurethane chain. .

The present invention is to propose a method for producing a novel water-dispersed polyurethane for improving the problem of physical properties of the water-dispersed polyurethane due to the anion center is inevitably introduced to perform the water dispersion as described above.

The present invention is a step 1 of reacting the chain extender and the diisocyanate compound in a 1: 2.5 to 3 weight ratio to prepare a hard segment at the end of the isocyanate group; Reacting 100 parts by weight of the hard segment, 295 to 310 parts by weight of polyol, and 65 to 80 parts by weight of the diisocyanate compound to prepare a prepolymer I having a hydroxyl group including a flexible segment; 3 steps of preparing prepolymer II by reacting 100 parts by weight of the prepolymer I, 2 to 3.5 parts by weight of diol having a carboxyl group and 2 to 4 parts by weight of the diisocyanate compound; And dispersing the prepolymer II to produce a water-dispersed polyurethane resin having a hard segment at the center of the chain and a soft segment at the end of the chain. The manufacturing method of resin has the characteristics.

The water-dispersed polyurethane resin of the present invention is located at the end of the soft segment by the carboxyl group of the anion center in the chain, so that the breakage of the particles during emulsification can be performed more easily, it is possible to disperse high solids content with a low anion content At the same time, it has high particle stability, and can be applied to various industrial applications such as paints, adhesives, textile treatment agents, and primers.

The present invention implements a new molecular design that places anion centers at the ends of soft segments by placing the hard segments at the chain centers, thereby changing the particle size and storage of the water-dispersed polyurethane through the change of the content of anion centers and the solids content of polyurethanes. It relates to a method for producing a water-dispersed polyurethane with improved physical properties such as stability, drying rate, hydrolysis resistance.

Looking at the method of producing a water-dispersed polyurethane according to the invention in more detail as follows.

First, the chain extender and the diisocyanate compound are reacted at a weight ratio of 1: 2.5 to 3 to prepare a hard segment at the end of the isocyanate group.

The chain extender is generally used in the art, and is not particularly limited, but a divalent anhydride may specifically use a low molecular weight diol or diamine based molecular weight ranging from 62 to 228. For example, ethylenediamine, One selected from butylenediamine, hexamethylenediamine, ethylenediol, butylenediol, and hexamethylenediol can be used. The diisocyanate compound is generally used in the art and is not particularly limited, but in order to more effectively improve the object of the present invention, it is preferable to use a linear aliphatic diisocyanate compound, and preferably 1,6-hexamethylene di Isocyanates, 4,4-dicycloheximethane diisocyanates, isophorone diisocyanates and mixtures thereof can be used, preferably 1,6-hexamethylene diisocyanate which increases the flexibility of the soft segments. .

When the diisocyanate compound is used in an amount of less than 2.5 parts by weight based on the weight of the chain extender, it is difficult to form isocyanates, and when it exceeds 3 parts by weight, it is difficult to form an appropriate molecular weight, so it is preferable to maintain the above range.

Next, 100 parts by weight of the hard segment, 295 to 310 parts by weight of the polyol, and 65 to 80 parts by weight of the diisocyanate compound are reacted to prepare a prepolymer I of the hydroxyl group including the soft segment. In this case, the hard segment is a urethane bond produced by the reaction of the diiso cyanate and the chain extender, and the soft segment refers to a polyurethane in which the polyol is mainly produced. The hard segment reinforces the soft segment into a hard glass phase at room temperature and influences strength, hardness and high temperature properties.

On the other hand, the soft segment exists in a rubbery state at room temperature at a low glass transition temperature, and the chain is entangled because of its molecular weight ranging from several hundred to thousands, thereby enabling high stretching.

The polyol is generally used in the art, and is not particularly limited. Specifically, an ether type or an ester type polyol may be used, and there is no particular limitation on physical properties such as molecular weight. The polyol is used in the range of 295 to 310 parts by weight based on 100 parts by weight of the hard segment. When the amount is less than 295 parts by weight, the soft segment at the hydroxy end cannot be obtained. It is desirable to maintain the above range because problems cannot be generated.

The diisocyanate compound is the same as mentioned above, and the diisocyanate compound is used in the range of 65 to 80 parts by weight based on 100 parts by weight of the hard segment, and when the amount is less than 65 parts by weight, it is difficult to form hydroxy end. When the content exceeds 80 parts by weight, it is preferable to maintain the above range because a problem of forming a soft segment having an appropriate molecular weight of interest is difficult.

The preparation of the hydroxyl group-terminated prepolymer I including the soft segment further includes catalyst components generally used in the art, specifically dibutyltindilaurate, sodium trichlorophenate, tetraisopropyl titanate, triethylamine, and the like. It is possible to use, preferably dibutyl tin dilaurate may be used.

The catalyst is used in the range of 0.14 to 0.2 parts by weight based on 100 parts by weight of the hard segment. When the amount is less than 0.14 parts by weight, the amount of the catalyst is insignificant and the reaction is performed very slowly. It is preferable to maintain the above range because it is too fast to control the viscosity during polymerization.

Next, 100 parts by weight of the prepolymer I, 2 to 3.5 parts by weight of a diol having a carboxyl group, and 2 to 4 parts by weight of the diisocyanate compound are reacted to prepare a prepolymer II.

The diol having the carboxyl group is generally used in the art, but is not particularly limited, and specifically, dimethylol propionic acid, dimethylol butanoic acid, or a mixture thereof may be used.

Diol having such a carboxyl group is used in the range of 2 to 3.5 parts by weight based on 100 parts by weight of prepolymer I. When the amount of the diol is less than 2 parts by weight, the content of anion center is small, so that it is difficult to disperse water. It is preferable to maintain the above range because there is a problem of not obtaining desired physical properties with anion center.

In addition, the diisocyanate compound is the same as mentioned above, and is used in the range of 2 to 4 parts by weight based on 100 parts by weight of prepolymer I, and when the amount is less than 2 parts by weight, a hydroxyl group terminal is not obtained, and more than 4 parts by weight. In this case, since there is a problem in not obtaining an appropriate molecular weight, it is preferable to maintain the above range.

Next, the prepolymer II is dispersed to prepare a water-dispersed polyurethane resin having a hard segment at the center of the chain and a soft segment at the end of the chain.

The water used for the water dispersion is used in the range of 100 to 200 parts by weight based on 100 parts by weight of the prepolymer II. When the amount of the water used is less than 100 parts by weight, stable particles are not obtained after the dispersion and when the amount is more than 200 parts by weight. It is preferable to maintain the above range because there is little solid content, so that the film thickness decreases after drying and the drying time is long.

The aqueous dispersion may be carried out after neutralizing the prepolymer II by a method generally used in the art, and the neutralization may be an amine, preferably a tertiary amine. The tertiary amine is used in the range of 1 to 2 parts by weight based on 100 parts by weight of prepolymer II. If the amount is less than 1 part by weight, the carboxyl group is not effectively neutralized, so that the hydrophilicity of the prepolymer is reduced and particle stability after dispersion is improved. When the amount exceeds 2 parts by weight, the problem of increase of soaking occurs, so it is preferable to maintain the above range.

The water-dispersed polyurethane resin prepared by the above method has a content of an anion center having a carboxyl group in the range of 2 to 3% by weight, and a solid content in the range of 30 to 45% by weight. It is stable by maintaining significantly improved zeta potential value while maintaining solid content.

Hereinafter, the present invention will be described in more detail based on the following examples, but the present invention is not limited to the examples.

Example 1

Nitrogen was injected into a 500 ml round four-necked flask equipped with a thermometer and a stirrer, and 1,4-butanediol and isophorone diisocyanate were reacted at 80 ° C. for about 5 hours in a 1: 2.67 weight ratio as shown in Table 1 below. Isocyanate group terminated hard segments were prepared. Subsequently, 100 parts by weight of the hard segment, 299.01 parts by weight of polytetramethylenediol having a molecular weight of 650, 68.96 parts by weight of hexamethylene diisocyanate, and 0.16 parts by weight of dibutyltin dilaurate were reacted at 80 ° C. for about 3 hours to react with a hydroxyl group. Prepolymer I was synthesized [Table 2]. Subsequently, 3.64 parts by weight of hexamethylene diisocyanate and 3.21 parts by weight of dimethylol butanoic acid were added to the prepolymer I, and reacted at 80 ° C. for about 1 hour to form an ion center [Table 3] to synthesize hydroxy-terminated prepolymer II. It was. Thereafter, as shown in Table 4, the mixture was stirred at a speed of 500 rpm for 3 hours while cooling to a temperature of 30 ° C., and neutralized by adding 2.05 parts by weight of triethylamine, a tertiary amine, to 100 parts by weight of the prepolymer II. Water dispersion polyurethane was prepared by adding 233.33 parts by weight of water to 100 parts by weight of prepolymer II to disperse water.

Example 2

The same procedure as in Example 1, except that the water dispersion polyurethane resin was prepared using the components shown in Tables 1 to 4.

Comparative Example 1

Following the use of the components of Tables 1 to 4, anion centers were first formed. 2.72 parts by weight of hexamethylene diisocyanate and 3.18 parts by weight of dimethylol butanoic acid were added thereto, and reacted at 80 ° C. for about 1 hour to form an ion center. Thereafter, 100 parts by weight of the hard segment, 295.67 parts by weight of polytetramethylenediol having a molecular weight of 650, 76.51 parts by weight of hexamethylene diisocyanate, and 0.16 parts by weight of dibutyltin dilaurate were reacted at 80 ° C. for about 3 hours to react at the hydroxyl group end. Prepolymer I was synthesized. Subsequently, 1,4-butanediol and isophorone diisocyanate were reacted with respect to the prepolymer I at a ratio of 1: 2.67 by weight for about 5 hours at 80 ° C. to synthesize prepolymer II including an isocyanate group terminal hard segment. Thereafter, as shown in Table 4, the mixture was stirred at a speed of 500 rpm for 3 hours while cooling to a temperature of 30 ° C., and neutralized by adding 2.05 parts by weight of triethylamine, a tertiary amine, to 100 parts by weight of the prepolymer II. Water dispersion polyurethane was prepared by adding 233.33 parts water by weight to 100 parts by weight of prepolymer II.

Classification (part by weight) usage 1,4-butanediol One Isophorone diisocyanate 2.67

Classification (part by weight) Example 1 Example 2 Comparative Example 1 Hard segment 100 100 100 Polytetramethylenediol 299.01 307.49 295.67 Hexamethylene diisocyanate 68.96 71.16 76.51 Dibutyl tin dilaurate 0.16 0.17 0.16

Classification (part by weight) Example 1 Example 2 Comparative Example 1 Prepolymer I 100 100 100 Dimethylol Butanoic Acid 3.21 2.09 3.18 Hexamethylene diisocyanate 3.64 2.37 2.72

Classification (part by weight) Example 1 Example 2 Comparative Example 1 Prepolymer II 100 100 100 Triethylamine 2.05 1.37 2.05 water 233.33 122.22 233.33

Example 3

In the same manner as in Example 1, but instead of polytetramethylenediol having a molecular weight of 650 as shown in Table 5 to change the molecular weight of polytetramethylenediol to 1000 to prepare a water-dispersible polyurethane,

Classification (part by weight) Example 3 Hard segment 100 Polytetramethylenediol 322.19 Hexamethylene diisocyanate 45.78 Dibutyl tin dilaurate 0.18

Experimental Example

Dispersion characteristics of the water-dispersed polyurethane prepared in Examples 1 to 3 and Comparative Example 1 were measured, and the results are shown in Table 6 below. At this time, the dispersed polyurethane was diluted 10,000-fold using deionized water, the measuring device was measured at an angle of 90 ° at room temperature using DLS-8000 (Otuska).

As shown in Table 6, the water-dispersed polyurethane of Examples 1 to 2 prepared according to the present invention was found to be very stable, as the zeta potential value was significantly increased compared to Comparative Example 1.

Specifically, Example 1 shows the same solid content and the content of anion center as in Comparative Example 1, but the zeta potential value shows a significant difference. In general, in the case of water dispersion, the anion is maintained at the end of the chain to maintain stability. This Example 1 of the present invention serves as a factor confirming that the soft segment is present at the end.

In addition, in Example 2, although the content of the anion center was significantly lower than that of Comparative Example 1, it was confirmed that the solid content and the zeta potential were significantly increased.

In conclusion, it was confirmed that the water-dispersed polyurethane of the present invention was stable by maintaining a significantly improved zeta potential value while maintaining the anion content and the solid content of the soft segment at the chain end.

1 illustrates a water dispersion polyurethane synthesis process according to an embodiment of the present invention.

Figure 2 shows a schematic diagram of the water-dispersed polyurethane prepared in Example 1 according to the present invention.

Claims (8)

A first step of reacting the chain extender with the diisocyanate compound at a ratio of 1: 2.5 to 3 to prepare a hard segment at the end of the isocyanate group; Reacting 100 parts by weight of the hard segment, 295 to 310 parts by weight of polyol, and 65 to 80 parts by weight of the diisocyanate compound to prepare a prepolymer I having a hydroxyl group including a flexible segment; 3 steps of preparing prepolymer II by reacting 100 parts by weight of the prepolymer I, 2 to 3 parts by weight of a diol having a carboxyl group, and 2 to 4 parts by weight of a diisocyanate compound; And Dispersing the prepolymer II to prepare a water-dispersible polyurethane resin having a hard segment at the center of the chain and a soft segment at the end of the chain. Method for producing a water-dispersed polyurethane resin of low ionic content and high solids content, characterized in that consisting of. The method of claim 1, wherein the water-dispersed polyurethane resin has a content of an anion center having a carboxyl group in the range of 2 to 3 wt%, and a solid content in the range of 30 to 45 wt%. The method according to claim 1, wherein the chain extender is a diol-based or diamine-based molecular weight ranging from 62 to 228. The method according to claim 1, wherein the second step is performed in the presence of 0.14-0.2 parts by weight of the dibutyl tin dilaurate catalyst. The method according to claim 1, wherein the diol having a carboxyl group is dimethylol propionic acid, dimethylol butanoic acid, or a mixture thereof. The method according to claim 1, wherein the aqueous dispersion is carried out after neutralization by adding 1 to 2 parts by weight of tertiary amine based on 100 parts by weight of prepolymer II. The method of claim 1, wherein the diisocyanate is an aliphatic compound selected from 1,6-hexamethylene diisocyanate, 4,4-dicyclohexemethane diisocyanate, isophorone diisocyanate, and mixtures thereof. . The method according to claim 1, wherein the polyol is an ether type or an ester type polyol.

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