Titanium modified phenolic resin and method of forming the same

Abstract

Titanium modified phenolic resin and a method of forming the same are provided. The method uses a one-pot sol-gel method with two-step synthesis, which includes following steps: phenol and titanium modifier are mixed to obtain an intermediate mixture; and the intermediate mixture reacts with polyoxymethylene to obtain the titanium modified phenolic resin. Homogeneity and stability, as well as thermomechanical property of the titanium modified phenolic resin, can be increased by the aforementioned method.

Description

[Technical Field]

[0001] This invention relates to a modified phenolic resin and a method for manufacturing the same, and particularly to a titanium phenolic resin and a method for manufacturing the same. [Previous Technology]

[0002] Phenolic resin is currently the most widely used synthetic resin due to its advantages such as simple raw materials, ease of synthesis, excellent thermomechanical properties, and environmental stability. Currently, the requirements for the thermomechanical properties of phenolic resins are gradually increasing, leading to the development and manufacture of modified phenolic resins with better performance. For example, significant progress has been made in the manufacturing methods of modified phenolic resins with different properties, such as metal-modified, amine-modified, boron-modified, silicon-modified, and epoxy-modified resins. However, there is still room for further improvement in the thermomechanical properties of conventionally modified phenolic resins.

[0003] Chinese Patent Publication No. CN 102329474A discloses an organosilicon and titanium-modified boron phenolic resin composite material and its manufacturing method. This method involves reacting uncured boron phenolic resin as a reactant with a titanium modifier to form a product. However, uncured phenolic resin often contains a large number of hydroxyl groups. If the sol-gel method is used to modify it with titanium, defects such as agglomeration, poor crosslinking, and low solubility may occur due to differences in hydroxyl activity and insufficient functional group density.

[0004] Chinese Patent Publication No. CN 112020533A discloses a method for manufacturing a titanate-modified phenolic resin composition, a titanate-modified phenolic resin composition, a phenolic resin composition for friction materials, and a friction material. This method involves heating and mixing phenolic resin, hexamethylenetetramine, and titanate compounds to suppress cracking during thermoforming, thereby improving moldability, friction coefficient, and stability. However, uncured phenolic resins often contain a large number of hydroxyl groups, which may lead to defects such as agglomeration, poor crosslinking, and low solubility due to differences in hydroxyl activity and insufficient functional group density.

[0005] In view of this, there is an urgent need to provide a titanium phenolic resin and a method for manufacturing the same, so as to avoid the above-mentioned defects caused by using phenolic resin directly as a reactant, and to improve the thermomechanical properties of the modified phenolic resin by modifying it with titanium. [Summary of the Invention]

[0006] One aspect of the present invention is to provide a method for manufacturing titanium phenolic resin, which involves mixing phenol and titanium modifier in a specific ratio and then reacting them with paraformaldehyde.

[0007] Another aspect of the present invention is to provide a titanium phenolic resin, which is prepared by the method described above.

[0008] According to one aspect of the present invention, a method for manufacturing titanium phenolic resin is provided. The method comprises mixing phenol and a titanium modifier to obtain an intermediate mixture, wherein the molar ratio of phenol to titanium modifier is 1:0.01 to 1:0.1; and adding paraformaldehyde to react the intermediate mixture with paraformaldehyde to obtain titanium phenolic resin, wherein the reaction temperature of the aforementioned reaction is 100°C to 150°C.

[0009] According to one embodiment of the present invention, the reaction temperature of the above-mentioned step of mixing phenol and titanium modifier is 80°C to 100°C, and the reaction time is 1 hour to 2 hours.

[0010] According to one embodiment of the present invention, the titanium modifier is selected from the group consisting of titanium tetrachloride, tetraisopropyl titanate, and tetra-n-butyl titanate.

[0011] According to one embodiment of the present invention, the above method further includes cooling the intermediate mixture to 60°C to 80°C before adding paraformaldehyde.

[0012] According to one embodiment of the present invention, the above-mentioned step of adding paraformaldehyde includes adding a catalyst. Based on the amount of phenol used being 100 wt%, the amount of catalyst added is 0.5 wt% to 10 wt%.

[0013] According to one embodiment of the present invention, the catalyst is selected from the group consisting of triethylamine, ammonium hydroxide, zinc oxide, magnesium oxide, tetrahydrofuran and zinc acetate.

[0014] According to one embodiment of the present invention, the above-mentioned paraformaldehyde decomposes into formaldehyde, and the molar ratio of phenol to formaldehyde is 1:1 to 1:2.

[0015] According to one embodiment of the present invention, the above reaction is carried out for 1 hour to 3 hours.

[0016] According to one embodiment of the present invention, the above method further includes adding a diluent to the titanium phenolic resin after the reaction, wherein the diluent is selected from the group consisting of ethanol, ethylene glycol and glycerol.

[0017] According to another aspect of the present invention, a titanium phenolic resin is provided, which is prepared by the above method.

[0018] The titanium phenolic resin and its manufacturing method of the present invention are synthesized in two steps using a sol-gel method in one pot. First, phenol and titanium modifier are mixed, and then it is reacted with paraformaldehyde to improve the homogeneity, stability and thermomechanical properties of the titanium phenolic resin.

Implementation Method

[0019] The manufacture and use of embodiments of the present invention will be discussed in detail below. However, it will be understood that the embodiments provide many applicable inventive concepts that can be implemented in a wide variety of specific situations. The specific embodiments discussed are for illustrative purposes only and are not intended to limit the scope of the invention.

[0020] As used in this invention, “around,” “about,” “approximately,” or “substantially” generally mean within 20 percent, 10 percent, or 5 percent of the stated value or range.

[0021] As described above, the present invention provides a titanium phenolic resin and its manufacturing method, which is synthesized in a one-pot two-step process using a sol-gel method, comprising first mixing phenol and titanium modifier, and then reacting with paraformaldehyde, thereby improving the homogeneity, stability and thermomechanical properties of the titanium phenolic resin.

[0022] The method for manufacturing titanium phenolic resin provided by the present invention involves first mixing phenol and a titanium modifier to form an intermediate mixture. In some embodiments, the molar ratio of phenol to titanium modifier is about 1:0.01 to about 1:0.1. If the amount of titanium modifier added is too small (e.g., the molar ratio is less than 0.01), the thermomechanical properties of the subsequently obtained titanium phenolic resin may not be effectively improved, and it may not have good stability; conversely, if the amount of titanium modifier added is too large (e.g., the molar ratio is greater than 0.1), it may result in the waste of excess titanium modifier and increase the cost of raw materials. In some embodiments, the titanium modifier may be titanium tetrachloride, tetraisopropyl titanate, tetra-n-butyl titanate, or any combination thereof.

[0023] Phenol and titanium modifier must be stirred in the reaction vessel to ensure uniform mixing. In some embodiments, when phenol and titanium modifier are mixed and reacted, the reaction temperature must be controlled at about 80°C to about 100°C, and the reaction time at about 1 hour to about 2 hours. The aforementioned reaction temperature allows the resulting intermediate mixture to have a suitable viscosity to facilitate subsequent reactions, and allows for control of the reaction time within an appropriate range, thereby increasing the homogeneity of the obtained titanium phenolic resin.

[0024] Next, in some embodiments, the intermediate mixture may be selectively cooled to about 60°C to about 80°C to reduce the reaction rate and avoid an increase in the viscosity of the intermediate mixture.

[0025] Then, paraformaldehyde is added to a reaction vessel containing the intermediate mixture, allowing the intermediate mixture to react with the paraformaldehyde to obtain titanium phenolic resin. In some embodiments, the reaction temperature is from about 100°C to about 150°C. If the reaction temperature is too low (e.g., below 100°C), the reaction rate is too slow and the viscosity of the reactants is too high; if the reaction temperature is too high (e.g., above 150°C), the reaction rate is too fast, making it difficult to control the viscosity and molecular weight of the product, and potentially causing premature curing. In some embodiments, this reaction is carried out for about 1 hour to about 3 hours.

[0026] Paraformaldehyde decomposes into formaldehyde after being added to the reaction system; therefore, the amount of paraformaldehyde added is determined based on the amount of formaldehyde produced after decomposition. In some embodiments, the molar ratio of phenol to formaldehyde is about 1:1 to about 1:2. When the molar ratio of phenol to formaldehyde is within the aforementioned range, it can effectively and completely react to form titanium phenol-formaldehyde resin. It should be understood that using paraformaldehyde improves the safety of the process compared to directly using formaldehyde as a reactant.

[0027] In some embodiments, a catalyst may be selectively added to this reaction, and the amount of catalyst added is from about 0.5 wt% to about 10 wt% based on 100 wt% of phenol. An appropriate amount of catalyst facilitates the reaction of the intermediate mixture with paraformaldehyde and can give the product suitable crosslinking degree and viscosity. In some embodiments, the catalyst may be triethylamine, ammonium hydroxide, zinc oxide, magnesium oxide, tetrahydrofuran, zinc acetate, or any combination thereof.

[0028] In some embodiments, after obtaining the titanium phenolic resin through the above reaction, steps such as vacuum distillation for dehydration, dilution, and cooling may be selectively performed. In the aforementioned embodiments, the dilution step includes adding a diluent to the titanium phenolic resin, and the diluent may be ethanol, ethylene glycol, glycerol, or any combination thereof. The dilution step is to improve the flowability of the titanium phenolic resin and increase the homogeneity of the obtained titanium phenolic resin.

[0029] The thermomechanical properties of phenolic resins stem from the rigidity of their benzene ring and network cross-linked structures. Generally, thermosetting phenolic resins with good cross-linking can withstand temperatures up to approximately 200°C without oxidation, thus exhibiting superior stability. Once the temperature exceeds 200°C, the methylene (-CH 2-) carbon bridges and phenolic hydroxyl groups (-OH) generated by the condensation of formaldehyde and phenol will gradually be superoxidized by oxygen or undergo structural decomposition. Therefore, this invention utilizes a sol-gel method to introduce phenolic hydroxyl groups into titanium for inorganic modification, thereby effectively increasing the temperature at which this decomposition mechanism occurs, and thus improving the thermomechanical properties and stability of the modified phenolic resin. Therefore, the titanium phenolic resin prepared by this invention can be used as a heat-resistant friction material and a refractory material.

[0030] The following examples illustrate the application of the present invention, but they are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention.

[0031] Example 1

[0032] 500 g (5.31 moles) of phenol and 30.7 g (108 mmol) of tetraisopropyl titanate were placed in a one-liter reactor and stirred with a fan-shaped mechanical stirrer at a speed of 250 to 500 rpm. After the phenol and tetraisopropyl titanate were uniformly mixed, the temperature was raised to 80°C to 100°C and the reaction was carried out for 1 to 2 hours. Then, the resulting intermediate mixture was cooled to 60°C, and 200 g of paraformaldehyde (formaldehyde equivalent 6.67 moles) and 16.7 g (76.1 mmol) of zinc acetate dihydrate were added and stirred uniformly. Then, a condenser was set up and the reaction was carried out at a temperature of 100°C to 120°C for 1 to 3 hours.

[0033] Next, the reflux liquid was collected over 1 hour and heated at a uniform rate to a temperature range of 120°C to 150°C. Upon reaching this temperature, 10 wt% to 20 wt% ethanol (based on 100 wt% phenol) was added to the reaction vessel for dilution and stirred until homogeneous. The resulting resin solution was then heated at 110°C to 130°C for 0.5 to 3 hours to evaporate the ethanol diluent and some of the volatile organic compounds in the solution. Thus, the thermosetting titanium phenolic resin of Example 1 was obtained.

[0034] Example 2

[0035] 500 g (5.31 moles) of phenol and 30.7 g (108 mmol) of tetraisopropyl titanate were placed in a one-liter reactor and stirred with a fan-shaped mechanical stirrer at a speed of 250 to 500 rpm. After the phenol and tetraisopropyl titanate were uniformly mixed, the temperature was raised to 80°C to 100°C and the reaction was carried out for 1 to 2 hours. Then, the resulting intermediate mixture was cooled to 60°C, and 200 g of paraformaldehyde (formaldehyde equivalent 6.67 moles), 3.37 g (33.3 mmol) of triethylamine, and 20 mL of tetrahydrofuran were added and stirred uniformly. Then, a condenser was set up and the reaction was carried out at a temperature of 100°C to 120°C for 1 to 3 hours.

[0036] Next, the reflux liquid was collected over 1 hour and heated at a uniform rate to a temperature range of 120°C to 150°C. Upon reaching this temperature, 10 wt% to 20 wt% ethylene glycol (based on 100 wt% phenol) was added to the reaction vessel for dilution and stirred until homogeneous. The resulting resin solution was then heated at 110°C to 130°C for 0.5 to 3 hours to evaporate the ethanol diluent and some of the volatile organic compounds in the solution. Thus, the thermosetting titanium phenolic resin of Example 2 was obtained.

[0037] Example 3

[0038] 500 g (5.31 moles) of phenol and 146.9 g (432 mmol) of tetrabutyl titanate were placed in a one-liter reactor and stirred with a fan-shaped mechanical stirrer at a speed of 250 to 500 rpm. After the phenol and tetraisopropyl titanate were uniformly mixed, the temperature was raised to 80°C to 100°C and the reaction was carried out for 1 to 2 hours. Then, the resulting intermediate mixture was cooled to 60°C, and 200 g of paraformaldehyde (formaldehyde equivalent 6.67 moles) and 16.7 g (76.1 mmol) of zinc acetate dihydrate were added and stirred uniformly. Then, a condenser was set up and the reaction was carried out at a temperature of 100°C to 120°C for 2 to 3 hours.

[0039] Next, the reflux liquid was collected over 1 hour and heated at a uniform rate to a temperature range of 120°C to 150°C. Upon reaching this temperature, 10 wt% to 20 wt% ethanol (based on 100 wt% phenol) was added to the reaction vessel for dilution and stirred until homogeneous. The resulting resin solution was then heated at 110°C to 130°C for 0.5 to 3 hours to evaporate the ethanol diluent and some of the volatile organic compounds in the solution. Thus, the thermosetting titanium phenolic resin of Example 3 was obtained.

[0040] Comparative Example 1

[0041] Take 500 g (5.31 moles) of phenol, 140 mL (37 wt%, 3.90 moles) of formaldehyde aqueous solution and 10.2 g (0.046 moles) of zinc acetate dihydrate and place them in a one-liter reactor. Stir with a fan-shaped mechanical stirring shaft at a speed of 250 to 500 rpm and control the temperature with a loop to keep it between 80°C and 120°C. Reflux for 2 to 3 hours to obtain a mixed solution of salicylol / phenolic resin oligomer.

[0042] Next, the reflux device was removed, and the temperature was uniformly increased to a discharge temperature range of 130°C to 180°C over 3 hours to obtain phenolic resin. After reaching the discharge temperature range, a total of 200 ml of alcohol diluent was added to the reaction vessel and stirred until homogeneous. Then, the resulting resin solution was heated at a temperature of 110°C to 130°C for 0.5 hours to 3 hours to evaporate the ethanol diluent and some of the volatile organic compounds in the solution. Thus, the thermosetting phenolic resin of Comparative Example 1 was obtained.

[0043] Comparative Example 2

[0044] Take 500 g (5.31 moles) of phenol, 140 mL (37 wt%, 3.90 moles) of formaldehyde aqueous solution and 10.2 g (0.046 moles) of zinc acetate dihydrate and place them in a one-liter reactor. Stir with a fan-shaped mechanical stirring shaft at a speed of 50 to 1000 rpm and control the temperature with a loop to keep it between 80°C and 120°C. Reflux for 2 to 3 hours to obtain a mixed solution of salicylol / phenolic resin oligomer.

[0045] Next, the reflux device was removed, and the temperature was uniformly increased to the discharge temperature range of 130°C to 180°C over 3 hours to obtain phenolic resin. After reaching the discharge temperature range, a total of 200 ml of alcohol diluent was added to the reaction vessel and stirred evenly. Then, the obtained resin solution was heated at a temperature of 110°C to 130°C for 0.5 hours to 3 hours to evaporate the ethanol diluent and some of the volatile organic compounds in the solution, obtaining thermosetting phenolic resin powder.

[0046] Next, 570 g of thermosetting phenolic resin powder was uniformly dissolved in 150 mL of tetrahydrofuran and placed in a one-liter reactor. The mixture was stirred using a fan-shaped mechanical stirrer at a speed of 50 to 1000 rpm. Then, a condenser was set up, and the temperature was raised to 60°C to 80°C. 36.7 g (108 mmol) of tetrabutyl titanate was added. After uniform mixing, the mixture was reacted at 100°C to 120°C for 1 to 1.5 hours. After the reaction, a thermosetting titanium phenolic resin solution was obtained and vacuum-dried at a vacuum degree of 0.1 to 1 tor, a temperature of 100°C to 120°C, and a duration of 1 to 3 hours. Thus, the thermosetting titanium phenolic resin of Comparative Example 2 was obtained.

[0047] The phenolic resins obtained in Examples 1 to 3 and Comparative Examples 1 to 2 were subjected to thermogravimetric analysis (TGA). The thermogravimetric loss of the titanium phenolic resins in Examples 1 to 3 was about 25% to about 30% at about 800°C.

[0048] Please refer to Figures 1 and 2. Figure 1 is the Fourier Transform Infrared (FTIR) spectrum of the titanium phenolic resin of Example 2 of the present invention (Figure 100), and Figure 2 is the thermogravimetric analysis (TGA) spectrum of the titanium phenolic resin of Example 2 of the present invention (Figure 200). As can be seen from Figure 1, there is an absorption peak at wavenumber 646 cm⁻¹, which is a characteristic absorption peak of the titanium-oxygen bond, thus proving that this method can indeed produce titanium-modified phenolic resin. As can be seen from Figure 2, the thermogravimetric loss of Example 2 at approximately 800°C is 27.6%.

[0049] The phenolic resin of Comparative Example 1 was not modified with titanium, so its thermogravimetric loss at about 800°C was about 40% to about 50%. In Comparative Example 2, titanium was introduced into the prepared thermosetting phenolic resin by reactive distillation, and its thermogravimetric loss at about 800°C was also about 40% to about 50%.

[0050] According to the above embodiments, the titanium phenolic resin and its manufacturing method provided by the present invention are synthesized in a two-step process using a sol-gel method in one pot. The process includes first mixing phenol and titanium modifier, and then reacting with paraformaldehyde, thereby improving the homogeneity, stability and thermomechanical properties of the titanium phenolic resin.

[0051] Although the present invention has been disclosed above with reference to several embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field to which the present invention pertains may make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims. [Simplified Explanation of the Diagram]

[0052] A better understanding of the present disclosure will be obtained by reading the following detailed description in conjunction with the accompanying drawings. It should be noted that, as is standard practice in the industry, many features are not drawn to scale. In fact, the dimensions of many features can be arbitrarily scaled for clarity of discussion. Figure 1 is a Fourier transform infrared spectrum of the titanium phenolic resin of Embodiment 2 of the present invention. Figure 2 is a thermogravimetric analysis diagram of the titanium phenolic resin of Embodiment 2 of the present invention. [Biomaterial Storage]

[0054] Domestic storage information (please note in order of storage institution, date, and number): None. International storage information (please note in order of storage country, institution, date, and number): None.

Claims

1. A method for manufacturing a titanium phenolic resin, comprising: mixing phenol and a titanium modifier to obtain an intermediate mixture, wherein the molar ratio of the phenol to the titanium modifier is 1:0.01 to 1:0.1; and adding paraformaldehyde and a catalyst to react the intermediate mixture with the paraformaldehyde to obtain the titanium phenolic resin, wherein the reaction temperature is 100°C to 150°C, and based on an amount of phenol of 100 wt%, the amount of catalyst added is 0.5 wt% to 10 wt%.

2. The method for manufacturing titanium phenolic resin as claimed in claim 1, wherein a reaction temperature of the step of mixing the phenol and the titanium modifier is 80°C to 100°C, and a reaction time is 1 hour to 2 hours.

3. The method for manufacturing titanium phenolic resin as claimed in claim 1, wherein the titanium modifier is selected from the group consisting of titanium tetrachloride, tetraisopropyl titanate, and tetra-n-butyl titanate.

4. The method for manufacturing titanium phenolic resin as described in claim 1 further comprises: cooling the intermediate mixture to 60°C to 80°C before adding the paraformaldehyde.

5. The method for manufacturing titanium phenolic resin as claimed in claim 1, wherein the catalyst is selected from the group consisting of triethylamine, ammonium hydroxide, zinc oxide, magnesium oxide, tetrahydrofuran and zinc acetate.

6. The method for manufacturing titanium phenolic resin as claimed in claim 1, wherein the paraformaldehyde decomposes into formaldehyde, and the molar ratio of phenol to formaldehyde is 1:1 to 1:

2.

7. The method for manufacturing titanium phenolic resin as described in claim 1, wherein the reaction is carried out for 1 hour to 3 hours.

8. The method for manufacturing titanium phenolic resin as claimed in claim 1 further comprises: after the reaction, adding a diluent to the titanium phenolic resin, wherein the diluent is selected from the group consisting of ethanol, ethylene glycol and glycerol.

9. A titanium phenolic resin, which is obtained by the manufacturing method of the titanium phenolic resin described in any one of claims 1 to 8.

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