Polyurethane resin and method for producing the same

Abstract

The present application discloses a polyurethane resin and a manufacturing method thereof, which comprises the following steps: mixing a polyester polyol, a polyether polyol, a first chain extender, a diisocyanate and a mixed solvent, and performing a polymerization reaction to obtain a prepolymer. A second chain extender is added to the prepolymer, and a chain extension reaction is performed to obtain the polyurethane resin. The mixed solvent comprises diethylformamide and butanone, and the mass ratio of diethylformamide to butanone in the mixed solvent is 0.45 to 1.80. The total amount of the first chain extender and the second chain extender is 0.9 wt% to 2.5 wt% based on 100 wt% of the total weight of the polyurethane resin. The polyurethane resin has good processability, bending resistance and peel strength.

Description

Technical Field

[0001] This invention relates to a polyurethane resin and a method for manufacturing the same, and more particularly to a polyurethane resin suitable for use as a shoe material and a method for manufacturing the same. Background Technology

[0002] Polyurethane is a multi-purpose polymer material, commonly used as the main raw material for artificial leather. By adjusting the types and composition of raw materials, polyurethane resins with different hardness can be synthesized.

[0003] Traditional polyurethane resins are manufactured using a wet process. Before curing, these resins contain organic solvents, such as dimethylformamide (DMF). While polyurethane resins containing DMF exhibit good stability, DMF has a high boiling point (153°C), requiring high temperatures to evaporate the solvent during curing, resulting in high energy consumption. Furthermore, DMF is a controlled toxic substance; once absorbed by the body, it is difficult to excrete, potentially causing permanent harm.

[0004] Therefore, traditional polyurethane resins have the disadvantage of high curing temperatures, and polyurethane products raise safety concerns, preventing their complete and safe application in all products. Thus, overcoming these shortcomings by improving manufacturing methods to synthesize polyurethane resins without using dimethylformamide has become one of the important issues this industry seeks to address. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a polyurethane resin and a method for manufacturing the same, addressing the shortcomings of the prior art.

[0006] To address the aforementioned technical problems, one technical solution adopted by this invention is to provide a method for manufacturing polyurethane resin. The method for manufacturing polyurethane resin includes the following steps: mixing a polyester polyol, a polyether polyol, a first chain extender, a diisocyanate, and a mixed solvent, and carrying out a polymerization reaction to obtain a prepolymer. A second chain extender is added to the prepolymer, and a chain extension reaction is carried out to obtain the polyurethane resin. The mixed solvent includes diethylformamide and butanone, and the mass ratio of diethylformamide to butanone in the mixed solvent is 0.45 to 1.80. Based on 100% by weight of the total weight of the polyurethane resin, the total amount of the first chain extender and the second chain extender added is 0.9% to 2.5% by weight.

[0007] Furthermore, the solvent in the polyurethane resin is removed at a processing temperature between 80°C and 110°C.

[0008] Furthermore, the amount of the second chain extender added is 3.5 to 4.8 times that of the first chain extender added.

[0009] Furthermore, based on 100% by weight of the total weight of the polyurethane resin, the content of polyester polyol is 18% to 28% by weight, the content of polyether polyol is 8% to 15% by weight, and the content of diisocyanate is 3% to 10% by weight.

[0010] Furthermore, the method for manufacturing polyurethane resin further includes: after the chain extension reaction, adding butanone to the polyurethane resin so that the mass ratio of diethylformamide to butanone in the polyurethane resin is 0.09 to 0.35.

[0011] Furthermore, the solid content of the polyurethane resin is 38% to 45%.

[0012] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is to provide a polyurethane resin, which is obtained by the aforementioned manufacturing method.

[0013] Furthermore, polyester polyols are polymerized from adipic acid and butanediol, while polyether polyols are linear polyether polyols with primary hydroxyl groups at both ends of the molecular chain.

[0014] Furthermore, the polyurethane resin includes a soft segment and a hard segment, wherein the soft segment accounts for 75% to 85% by weight and the hard segment accounts for 15% to 25% by weight.

[0015] Furthermore, the viscosity of polyurethane resin is between 20,000 cps and 30,000 cps.

[0016] Furthermore, the weight average molecular weight of the polyurethane resin is between 90,000 g / mol and 110,000 g / mol.

[0017] Furthermore, the peel strength of the cured polyurethane resin relative to a polyurethane substrate is from 12.0 kg / 3 cm to 18.0 kg / 3 cm.

[0018] One of the beneficial effects of the present invention is that the polyurethane resin and its manufacturing method provided by the present invention can improve the processability, flexural resistance and peel strength of the polyurethane resin by using the technical solutions of "the mass ratio of diethylformamide to methyl ethyl ketone in the mixed solvent is 0.45 to 1.80" and "the total addition amount of the first chain extender and the second chain extender is 0.9% to 2.5% by weight".

[0019] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the manufacturing method of the polyurethane resin of the present invention. Detailed Implementation

[0021] The following specific examples illustrate the embodiments of the "polyurethane resin and its manufacturing method" disclosed in this invention. Those skilled in the art can understand the advantages and effects of this invention from the content disclosed in this specification. This invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of this invention. Furthermore, the accompanying drawings of this invention are for simple illustrative purposes only and are not depictions of actual dimensions, as stated in advance. The following embodiments will further describe the relevant technical content of this invention in detail, but the disclosed content is not intended to limit the scope of protection of this invention. In addition, the term "or" as used herein may include, depending on the actual situation, any combination of any one or more of the associated listed items.

[0022] To address the aforementioned problems, this invention provides a method for manufacturing polyurethane resin that eliminates the need for dimethylformamide during the manufacturing process, thereby reducing the product's toxicity to humans. Furthermore, the resulting polyurethane resin exhibits advantages such as good processability, excellent flexural resistance, and high peel strength, meeting the current market demand for applying polyurethane resins in footwear materials.

[0023] Please see Figure 1 As shown, the method for manufacturing polyurethane resin of the present invention includes the following steps: mixing polyester polyol, polyether polyol, a first chain extender, diisocyanate and a mixed solvent, and carrying out a polymerization reaction to obtain a prepolymer (step S1); adding a second chain extender to the prepolymer and carrying out a chain extension reaction to obtain polyurethane resin (step S2); adding butanone to the polyurethane resin to make the solid content of the polyurethane resin 38% to 45% (step S3).

[0024] The solid components that form polyurethane resin include: polyester polyol, polyether polyol, chain extenders (first chain extender and second chain extender), and diisocyanate. If the total weight of the solid components in the polyurethane resin is 100% by weight, the content of polyester polyol is 48% to 63% by weight, the content of polyether polyol is 20% to 30% by weight, the content of chain extender is 1.5% to 8% by weight, and the content of diisocyanate is 10% to 20% by weight.

[0025] The polyurethane resin of the present invention comprises a soft segment and a hard segment. The soft segment is composed of polyester polyol and polyether polyol, and the hard segment is composed of diisocyanate and chain extender. The blending of the soft segment and the hard segment can give the polyurethane resin better flexural resistance.

[0026] In a preferred embodiment, the weight percentage of soft segments is higher than that of hard segments. Specifically, with the total weight of the solid components in the polyurethane resin as 100% by weight, the polyurethane resin includes 75% to 85% by weight of soft segments and 15% to 25% by weight of hard segments. In this way, the polyurethane resin, after polymerization, can possess good physical properties and can be used in footwear materials.

[0027] In a preferred embodiment, the polyester polyol is an adipic acid-based polyester polyol. For example, the monomers for synthesizing the polyester polyol may include adipic acid and butanediol, the number average molecular weight of the polyester polyol is from 1000 g / mol to 3000 g / mol, the hydroxyl value of the polyester polyol is from 35 to 39, and the acid value of the polyester polyol is from 0.4 to 0.6. However, the invention is not limited thereto.

[0028] In a preferred embodiment, the polyether polyol is a linear polyether polyol with primary hydroxyl groups at the molecular ends. For example, the polyether polyol may be tetrahydrofuran homopolymer ether (number average molecular weight from 1000 g / mol to 3000 g / mol) or polypropylene glycol (number average molecular weight from 1000 g / mol to 4000 g / mol), wherein the number average molecular weight of the polyether polyol is from 1000 g / mol to 4000 g / mol. However, the invention is not limited thereto.

[0029] In a preferred embodiment, the first chain extender and the second chain extender are each independently selected from the group consisting of ethylene glycol, 1,4-butanediol, and 1,6-hexanediol. The first chain extender and the second chain extender may be the same or different; in a preferred embodiment, the first chain extender and the second chain extender are the same.

[0030] In a preferred embodiment, the diisocyanate may be selected from the group consisting of: methylenediphenyl diisocyanate (MDI), toluenediisocyanate (TDI), and isophorone diisocyanate (IPDI). However, the invention is not limited thereto.

[0031] In this invention, chain extenders are added in steps S1 and S2 respectively, and the amount of the second chain extender added is controlled to be greater than the amount of the first chain extender added. This improves the flexural resistance of the polyurethane resin. In a preferred embodiment, the amount of the second chain extender added is 3.5 to 4.8 times that of the first chain extender added; specifically, the amount of the second chain extender added can be 3.6, 3.8, 4.0, 4.2, 4.4, or 4.6 times that of the first chain extender added.

[0032] In this invention, the phased addition of chain extenders enables polyurethane resins to possess better processability, peel strength, and flexural resistance. The addition of the first chain extender appropriately extends the molecular chain length of the polyurethane resin. The addition of the second chain extender further enables the polyurethane resin to achieve an ideal molecular chain length and improves its processability, peel strength, and flexural resistance.

[0033] It is worth noting that if the amount of the second chain extender added is too low, the structural strength of the polyurethane resin will be insufficient, which will negatively affect the processability, peel strength, and flexural strength of the polyurethane resin. Specifically, based on the total weight of the polyurethane resin (including solid and liquid components) as 100% by weight, the amount of the first chain extender added can be 0.2% to 0.6% by weight, and the amount of the second chain extender added can be 0.9% to 2.5% by weight.

[0034] The timing of adding the second chain extender also affects the properties of the polyurethane resin in order to polymerize the desired polyurethane resin. In a preferred embodiment, the second chain extender is added to the prepolymer when the isocyanate group (-NCO) content is 1.0 to 2.0% by weight to proceed to step S2.

[0035] On the other hand, in order to ensure good compatibility and reactivity of the solid components (polyester polyols, polyether polyols, chain extenders and diisocyanates), this invention selects diethylformamide and butanone as solvents (liquid components) to replace toxic dimethylformamide.

[0036] During the polymerization reaction (steps S1 and S2), the addition of diethylformamide can improve the compatibility and reactivity of the polyurethane resin. However, too much or too little diethylformamide will negatively affect the compatibility and physical properties of the polyurethane resin. Therefore, this invention controls the amount of diethylformamide added and mixes an appropriate amount of butanone to adjust the solid content of the polyurethane resin to facilitate the polymerization reaction.

[0037] In a preferred embodiment, the mass ratio of diethylformamide to butanone in the mixed solvent is from 0.45 to 1.80. Specifically, the mass ratio of diethylformamide to butanone in the mixed solvent can be a value in an arithmetic sequence with a tolerance of 0.05 between 0.45 and 1.80 (e.g., 0.45, 0.50, 0.55...1.70, 1.75, 1.80).

[0038] Specifically, based on the total weight of the polyurethane resin (including solid and liquid components) as 100% by weight, the amount of diethylformamide added is from 5% to 16% by weight. For example, the amount of diethylformamide added can be 6%, 8%, 10%, 12%, or 14% by weight.

[0039] It is worth noting that the addition of methyl ethyl ketone (MEK) in step S1 maintains the solid content of the polyurethane resin at a concentration conducive to the reaction. The addition of MEK in step S3 adjusts the solid content of the polyurethane resin to 38% to 45%. Furthermore, the addition of MEK lowers the evaporation temperature of the solvent in the polyurethane resin, thereby reducing the energy consumption required to cure the polyurethane resin. Specifically, the solvents (MEK and diethylformamide) in the polyurethane resin can be removed at a processing temperature of 80°C to 110°C.

[0040] Specifically, taking the total weight of the polyurethane resin (including solid and liquid components) as 100% by weight, the amount of methyl ethyl ketone (MEK) added in step S1 is 6% to 12% by weight, and the amount of MEK added in step S3 is 32% to 45% by weight. The total amount of MEK added to the polyurethane resin is 40% to 60% by weight.

[0041] To demonstrate the advantages of the polyurethane resin of the present invention, such as good processability, excellent flexural resistance and high peel strength, polyurethane resins of Examples 1 to 4 (E1 to E4) and Comparative Examples 1 to 3 (C1 to C3) were prepared according to the following steps, and the specific addition amounts of each component are shown in Table 1.

[0042] In step S1, adipic acid-based polyester polyol (polyester polyol), tetrahydrofuran homopolymer ether (polyether polyol), 1,6-hexanediol (first chain extender), diethylformamide (DEF), and butanone (MEK) (mixed solvent) are first added to a reaction vessel, and the temperature is raised to 70°C under continuous stirring. Next, diphenylmethane diisocyanate (diisocyanate) and a small amount of catalyst are added to the reaction vessel, and the temperature is raised to 78°C and reacted for two hours to prepare the prepolymer.

[0043] In step S2, 1,6-hexanediol (a second chain extender) is added to the prepolymer, and the reaction is carried out at 78°C for one hour to obtain polyurethane resin.

[0044] In step S3, after the polyurethane resin cools down to below 45°C, methyl ethyl ketone is added to dilute the solid content of the polyurethane resin to 38% to 45% (preferably 39% to 41%).

[0045] After preparation, the polyurethane resins of Examples 1 to 4 (E1 to E4) and Comparative Examples 1 to 3 (C1 to C3) were tested for viscosity, weight-average molecular weight, processability, peel strength and flexural strength, respectively.

[0046] Viscosity was measured using a viscometer (Brand: BROOKFIELD, Model: DV-E). Weight-average molecular weight was measured using a gel permeation analyzer (Brand: SHIMADZU, Model: LC-40XR). Processability was assessed at processing temperatures between 80°C and 110°C for any abnormalities in coatability; "OK" indicated no abnormalities, and "NG" indicated any abnormalities. Peel strength was measured using a universal tensile testing machine (Brand: SHIMADZU, Model: AG-X). Flexural strength at room temperature was assessed using a flexural strength testing machine (Brand: GOTECH, Model: GT-7006-V50) at an angle of 22.5°, a frequency of 100 cycles / minute, and 100,000 cycles at 25°C. "OK" indicated no abnormalities or damage, and "NG" indicated any abnormalities or damage. The evaluation of low-temperature flexural resistance is carried out using a flexural resistance tester (brand: GOTECH, model: GT-7006-V50) at an angle of 22.5°, a frequency of 100 times / minute, and 10,000 times at -10℃. If there are no abnormal defects or damage, it is indicated as "OK"; if there are abnormal defects or damage, it is indicated as "NG".

[0047] Table 1

[0048]

[0049] As shown in Table 1, the polyurethane resin of the present invention has good processability, can be solvent-removed at processing temperatures of 80°C to 110°C, and has good coating smoothness. The polyurethane resin of the present invention exhibits flexural resistance at both room temperature and low temperature. It can withstand 100,000 flexural tests at room temperature (25°C) and 10,000 flexural tests at low temperature (-10°C).

[0050] The polyurethane resin of this invention has a peel strength greater than 12 kg / 3 cm. Specifically, the peel strength of the polyurethane resin relative to a polyurethane substrate can be from 12.0 kg / 3 cm to 18.0 kg / 3 cm. That is to say, the polyurethane resin has good bonding strength to the polyurethane material.

[0051] Furthermore, the viscosity of the polyurethane resin of the present invention can be from 20,000 cps to 30,000 cps, preferably from 25,000 cps to 30,000 cps. The weight-average molecular weight of the polyurethane resin of the present invention can be from 90,000 g / mol to 110,000 g / mol, preferably from 92,000 g / mol to 109,000 g / mol. However, the present invention is not limited thereto.

[0052] As can be seen from Comparative Example 1, when the concentration of the chain extender (first chain extender and second chain extender) is insufficient (less than 0.9% by weight), the polyurethane resin of the present invention cannot be obtained. The concentration of the second chain extender is preferably from 0.9% to 2.5% by weight.

[0053] As can be seen from Comparative Examples 2 and 3, the mass ratio of diethylformamide to methyl ethyl ketone in the mixed solvent affects the properties of the polyurethane resin. When the mass ratio of diethylformamide to methyl ethyl ketone is less than 0.9% by weight (Comparative Example 2) or greater than 2.5% by weight (Comparative Example 3), the polyurethane resin of the present invention cannot be obtained.

[0054] [Beneficial Effects of the Examples]

[0055] One of the beneficial effects of the present invention is that the polyurethane resin and its manufacturing method provided by the present invention can improve the processability, flexural resistance and peel strength of the polyurethane resin by using the technical solutions of "the mass ratio of diethylformamide to methyl ethyl ketone in the mixed solvent is 0.45 to 1.80" and "the total addition amount of the first chain extender and the second chain extender is 0.9% to 2.5% by weight".

[0056] Furthermore, the present invention, through the technical solution of "mixed solvent including diethylformamide and methyl ethyl ketone", can improve the compatibility and reactivity between solid components in polyurethane resin, and can also make polyurethane resin have good processability.

[0057] Furthermore, the present invention improves the processability, flexural strength and peel strength of polyurethane resin by using a technical solution in which "the amount of the second chain extender added is 3.5 to 4.8 times that of the first chain extender".

[0058] Furthermore, the present invention improves the processability of polyurethane resin by adding methyl ethyl ketone to the polyurethane resin after the chain extension reaction, so that the mass ratio of diethylformamide to methyl ethyl ketone in the polyurethane resin is 0.09 to 0.35.

[0059] The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of protection of the claims of the present invention. Therefore, all equivalent technical changes made based on the content of the present invention specification and drawings are included within the scope of protection of the claims of the present invention.

Claims

1. A method for manufacturing a polyurethane resin, characterized in that, The method for manufacturing the polyurethane resin includes: A prepolymer is obtained by polymerizing a polyester polyol, a polyether polyol, a first chain extender, a diisocyanate, and a mixed solvent; wherein the mixed solvent comprises diethylformamide and butanone, and the mass ratio of diethylformamide to butanone in the mixed solvent is 0.45 to 1.

80. A second chain extender is added to the prepolymer to carry out a chain extension reaction to obtain a polyurethane resin solution; Butyl ketone is added to the polyurethane resin solution to make the mass ratio of diethylformamide to butyl ketone in the polyurethane resin solution 0.09 to 0.35; and The solvent in the polyurethane resin solution is removed to obtain the polyurethane resin. Wherein, with the total weight of the polyurethane resin solution as 100% by weight, the total addition amount of the first chain extender and the second chain extender is 0.9% to 2.5% by weight.

2. The manufacturing method according to claim 1, characterized in that, The solvent in the polyurethane resin solution is removed at a processing temperature between 80°C and 110°C.

3. The manufacturing method according to claim 1, characterized in that, The amount of the second chain extender added is 3.5 to 4.8 times that of the first chain extender added.

4. The manufacturing method according to claim 1, characterized in that, With the total weight of the polyurethane resin solution as 100% by weight, the content of the polyester polyol is 18% to 28% by weight, the content of the polyether polyol is 8% to 15% by weight, and the content of the diisocyanate is 3% to 10% by weight.

5. The manufacturing method according to claim 1, characterized in that, The solid content of the polyurethane resin solution is 38% to 45%.

6. A polyurethane resin, characterized in that, The polyurethane resin is obtained by the manufacturing method according to any one of claims 1 to 5.

7. The polyurethane resin according to claim 6, characterized in that, The polyester polyol is polymerized from adipic acid and butanediol, and the polyether polyol is a linear polyether polyol with primary hydroxyl groups at both ends of the molecular chain.

8. The polyurethane resin according to claim 6, characterized in that, The polyurethane resin comprises a soft segment and a hard segment, wherein the soft segment accounts for 75 to 85% by weight and the hard segment accounts for 15 to 25% by weight.

9. The polyurethane resin according to claim 6, characterized in that, The polyurethane resin has a weight average molecular weight of 90,000 g / mol to 110,000 g / mol.

Images