A modified phenolic resin and its preparation method and application

Abstract

The invention discloses a modified phenolic resin and a preparation method and application thereof, the preparation method of the modified phenolic resin, comprising the steps of: S1. mixing water, lignin and an alkaline catalyst in a reactor, reacting 1 3h, S2. adding phenol to the reaction mixture of step S1, continuing the reaction 1 2h, S3. adding cardanol and aldehyde to the reaction mixture of step S2, reacting 1.5 3h, S4. adding boric acid to the reaction mixture of step S3, reacting 0.5 2h, S5. adding methanol after vacuum dehydration of the reaction mixture obtained in step S4, and being made into a resin solution, that is, obtaining the modified phenolic resin. The modified phenolic resin obtained by the preparation method of the present invention can ensure that the pad has high flatness, excellent heat resistance, toughness and punching property when applied to a drilling pad, and the modification method of the present invention can also reduce the preparation cost of the modified phenolic resin, and also has certain environmental benefits.

Description

Technical Field

[0001] The invention relates to the technical field of phenolic resin production, and in particular to a modified phenolic resin and a preparation method and application thereof. Background Art

[0002] Phenolic resin is the earliest synthetic resin used in industrial production. It is made by the polycondensation reaction of phenolic compounds and aldehyde compounds. It accounts for a large proportion of the application fields of polymer materials and is widely used as the main resin in the drilling pad industry. However, phenolic resin has the disadvantages of high raw material cost and non-renewable, high brittleness and poor toughness, poor flatness and large warping, which limits the development of high-performance drilling pads. Modifying phenolic resin by chemical methods is currently an effective solution.

[0003] Lignin is a renewable natural organic polymer, non-petroleum aromatic compound. Lignin molecules contain more aldehyde groups and hydroxyl groups. Hydroxyl groups exist in the form of alcohol hydroxyl groups and aldehyde hydroxyl groups. Under certain conditions, they can replace part of phenol or formaldehyde to participate in the condensation reaction of phenolic resin, replace the use of some phenols, reduce costs, and improve the brittleness of phenolic resin. The effective use of lignin is not only in line with the path of sustainable development, but also can solve the problem of environmental pollution. However, the reaction activity of lignin is low, and the amount of reaction participation is limited. If the amount of reaction participation is increased by increasing the amount of addition, the heat resistance of the material will be significantly reduced, and the fluidity of phenolic resin will also be affected. Cardanol is extracted from cashew nut oil squeezed from cashew nut shells. It is rich in resources, low in price, and has unique properties. Because its main structure contains a 15-carbon monoolefin or diene long-chain phenol at the meta position, cardanol has both the characteristics of phenolic compounds and the flexibility of aliphatic compounds. Its modification can reduce costs and improve the toughness of phenolic resin, but excessive replacement of cardanol will lead to a decrease in the softening point of the resin and a decrease in heat resistance. It can be seen that both single-component and double-modified phenolic resins have some shortcomings. Although they can improve some properties of phenolic resins, they will sacrifice heat resistance, etc.

[0004] Therefore, there is an urgent need for a new method for preparing modified phenolic resin to reduce the preparation cost of modified phenolic resin and enable the prepared modified resin to give the drilling pad excellent toughness, punching property and flatness while maintaining heat resistance when it is made into a drilling pad. Summary of the invention

[0005] In view of the defects in the prior art, the present invention provides a modified phenolic resin and a preparation method and application thereof.

[0006] The present invention provides a method for preparing a modified phenolic resin, comprising the following steps:

[0007] S1. Mix water, lignin and alkaline catalyst in a reactor and react for 1-3h;

[0008] S2. Add phenol to the reaction mixture of step S1 and continue the reaction for 1-2h;

[0009] S3. Add cardanol and aldehyde to the reaction mixture of step S2 and react for 1.5-3h;

[0010] S4. Add boric acid to the reaction mixture of step S3 and react for 0.5-2h;

[0011] S5. The reaction mixture obtained in step S4 is vacuum-dehydrated and then methanol is added to prepare a resin solution to obtain the modified phenolic resin;

[0012] The present invention uses lignin, cardanol and boric acid to perform three-component modified phenolic resin, which can overcome the shortcomings of single-component and double-modified phenolic resins, further improve their performance, and reduce costs. The pad made of the modified phenolic resin has good toughness, punchability, flatness, and excellent heat resistance, and can reduce costs and have certain environmental benefits.

[0013] The inventors found that in the process of preparing the modified phenolic resin, lignin is first added in step S1 for reaction, lignin and water are hydrolyzed under alkaline conditions, lignin is degraded into a small molecular weight, its water solubility is enhanced, the proportion of reactive components contained therein can be increased, and the reaction activity of lignin is improved; phenol is added in step S2, lignin can be further hydrolyzed and converted into phenolic compounds, and the reaction activity of lignin is enhanced; cardanol and aldehyde are added in step S3, at this time, composite hydroxymethylation and preliminary condensation reaction of lignin, phenol and cardanol are carried out in the system, and the brittleness of the phenolic resin is improved by introducing the long straight chain of cardanol, and its toughness is enhanced; in step S4, phenol is added in step S5, phenol is added in step S6, and the phenolic resin is hydrolyzed and converted into phenolic compounds, and the reaction activity of lignin is enhanced; in step S7, phenol is added in step S8, phenol is added in step S9, phenol is added in step S10, phenol is added in step S11, phenol is added in step S12, phenol is added in step S13, phenol is added in step S14, phenol is added in step S15, phenol is added in step S16, phenol is added in step S17, phenol is added in step S18, phenol is added in step S19, phenol is added in step S20, phenol is added in step S21, phenol is added in step S22, phenol is added in step S19, phenol is added in step S11, phenol is added in step S12, phenol is added in step S13, phenol is added in step S14, phenol is added in step S15, phenol is added in step S16, phenol is added in step S17, phenol is added in step S18, phenol is added in step S19 Adding boric acid in step S4 can further cross-link the product, increase the molecular weight of the resin, and overcome the defects of decreased heat resistance of the resin caused by the non-reactive components in lignin and the increased amount of cardanol. The present invention uses lignin, cardanol and boric acid to modify the phenolic resin. Through the specific feeding sequence of each component and the reaction between the components, it not only promotes the activation and improvement of the reaction activity of lignin, but also smoothly introduces the long chain of cardanol to change the brittleness of the resin and enhance the toughness. The heat resistance of the resin is strengthened by cross-linking with boric acid, which provides a guarantee for the performance of the synthetic resin and the pad made thereof. The preparation method of the present invention is environmentally friendly while reducing costs.

[0014] Furthermore, the lignin is any one or more of enzymatically hydrolyzed lignin, lignin sulfonate, alkali lignin or high-boiling alcohol lignin.

[0015] Furthermore, the phenol is any one or more of phenol, nonylphenol, cresol, xylenol, bisphenol A or resorcinol, preferably phenol.

[0016] Furthermore, the aldehyde is any one or more of formaldehyde solution, acetaldehyde, butyraldehyde or paraformaldehyde, preferably formaldehyde solution, more preferably 37% formaldehyde solution (mass fraction).

[0017] Furthermore, the alkaline catalyst is any one or more of ammonia water, methylamine, ethylamine, ethylenediamine, triethylamine, sodium hydroxide solution or barium hydroxide; preferably 30% sodium hydroxide solution (mass fraction).

[0018] Furthermore, the amount of the alkaline catalyst is 2-9% of the mass of the phenol.

[0019] Furthermore, the mass ratio of phenol, water, lignin, cardanol, boric acid and aldehyde is: (98-102): (48-52): (10-40): (20-60): (5-20): (100-260); the inventors also designed the mass ratio of each substance to promote the efficient and stable modification reaction. Among them, the amount of lignin affects the adhesion, heat resistance and flatness of the modified resin. However, if the mass ratio is too low, the purpose of reducing the preparation cost of the modified resin cannot be achieved. If the mass ratio is too high, the components that do not participate in the reaction are easy to precipitate, affecting the adhesive. In order to improve the stability of the liquid and the heat resistance of the modified resin, the present invention increases the proportion of the reactive components of lignin and enhances its reaction activity by designing the addition of lignin in step S1, thereby increasing the amount of lignin used and the resin performance, thereby achieving the purpose of further reducing the modification cost; the amount of boric acid involved in the reaction is a more important factor in controlling the resin performance. When the mass ratio of boric acid is within the range of the present invention, it is beneficial to improve the crosslinking ability of the reaction mixture, thereby improving the heat resistance. When the mass ratio falls outside the range, the crosslinking ability decreases, and it is difficult to make up for the defect of decreased heat resistance caused by lignin / cardanol.

[0020] Furthermore, the preparation method of the modified phenolic resin comprises the following steps:

[0021] S1. Mix water, lignin and alkaline catalyst in a reactor, heat to 60-80°C for reaction for 0.5-1h, and then heat to 90-100°C for reaction for 1-2h; pH value in step S1 is 8-12, which can be adjusted by acid-base regulator or adding alkali solution; low temperature reaction section is conducive to hydrolysis and phenolization of low molecular weight lignin, and high temperature reaction section is conducive to hydrolysis and phenolization of high molecular weight lignin;

[0022] S2. The reaction mixture of step S1 is cooled to 60-80°C, phenol is added, and the temperature is raised to 90-100°C and the reaction is continued for 1-2h;

[0023] S3. The reaction mixture of step S2 is cooled to 60-80 ° C, cardanol and aldehyde are added, and the reaction is carried out at a temperature of 80-100 ° C for 1.5-3h;

[0024] S4. Add boric acid to the reaction mixture of step S3 and react at 90-110° C. for 0.5-2 h;

[0025] S5. The reaction mixture obtained in step S4 is vacuum-dehydrated and then cooled, and methanol is added to prepare a resin solution to obtain the modified phenolic resin.

[0026] Furthermore, the amount of methanol added is 45-55% of the mass of phenol.

[0027] The invention also provides a modified phenolic resin prepared by the preparation method.

[0028] The invention also provides application of the modified phenolic resin in preparing a drilling pad.

[0029] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0030] (1) The pad made of the modified phenolic resin provided by the present invention has excellent toughness, flatness, and punchability while also ensuring excellent heat resistance;

[0031] (2) The preparation method of the modified phenolic resin provided by the present invention can reduce the modification cost and has environmental benefits. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] Example

[0034] The present invention is further described below in conjunction with specific examples and comparative examples. The following specific examples are all preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and are particularly not limited to the types of the various component raw materials used in the following specific examples.

[0035] 1. The sources of raw materials for the embodiments and comparative examples are as follows:

[0036] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present invention are commercially available.

[0037] 2. Various performance test methods

[0038] The modified phenolic resin prepared in the embodiment and the comparative example was impregnated with bleached wood pulp paper to make a sheet with a glue content of 45-50%. Five sheets were stacked and cured in a hot press at a temperature of 160°C for 60 minutes to obtain a pad with a thickness of 1.0 mm. The pad was then tested for performance:

[0039] (1) Pad bending strength test: Tested in accordance with GB / T 4723-2017.

[0040] (2) Heat resistance test of pad: Tested according to GB / T 5132-2019.

[0041] (3) Pad punching test: Tested in accordance with GB / T 4723-2017.

[0042] (4) Pad warping test: Tested in accordance with GB / T1448-2005.

[0043] Example 1

[0044] The preparation method of the modified phenolic resin of Example 1 comprises the following steps:

[0045] S1. Add 60g of water, 6.2g of 30% sodium hydroxide solution and 36g of enzymatic lignin into a three-necked flask, stir evenly, heat to 70°C for 1h, and then heat to 100°C for 2h;

[0046] S2. The reaction mixture of step S1 was cooled to 70°C, 120 g of phenol was added, and the temperature was raised to 90°C for 1.5 h;

[0047] S3. The reaction mixture of step S2 was cooled to 60 ° C, 48 g of cardanol and 180 g of 37% formaldehyde were added, and the temperature was raised to 90 ° C for 2 h;

[0048] S4. Add 12 g of boric acid to the reaction mixture in step S3 and heat to 100 ° C for 1 h;

[0049] S5. The reaction mixture obtained in step S4 is evacuated to (-0.08) MPa for dehydration and then cooled, and 50% of the mass of phenol in methanol is added to obtain a modified phenolic resin.

[0050] Example 2

[0051] The preparation method of the modified phenolic resin of Example 2 comprises the following steps:

[0052] S1. Add 60g of water, 8.4g of 30% sodium hydroxide solution and 24g of enzymatic lignin into a three-necked flask, stir evenly, heat to 80°C for 1h, and then heat to 100°C for 1.5h;

[0053] S2. The reaction mixture of step S1 was cooled to 70°C, 120 g of phenol was added, and the temperature was raised to 90°C for 2 h;

[0054] S3. The reaction mixture of step S2 was cooled to 60 ° C, 48 g of cardanol and 240 g of 37% formaldehyde were added, and the temperature was raised to 90 ° C for 2.5 h;

[0055] S4. Add 20 g of boric acid to the reaction mixture in step S3 and heat to 90 ° C for 0.5 h;

[0056] S5. The reaction mixture obtained in step S4 is evacuated to (-0.08) MPa for dehydration and then cooled, and 50% of the mass of phenol in methanol is added to obtain a modified phenolic resin.

[0057] Example 3

[0058] The preparation method of the modified phenolic resin of Example 3 comprises the following steps:

[0059] S1. Add 60g of water, 10.6g of 30% sodium hydroxide solution and 45g of enzymatic lignin into a three-necked flask, stir evenly, heat to 70°C for 0.5h, and then heat to 100°C for 2h;

[0060] S2. The reaction mixture of step S1 was cooled to 70°C, 120 g of phenol was added, and the temperature was raised to 100°C for 2 h;

[0061] S3. The reaction mixture of step S2 was cooled to 60 ° C, 66 g of cardanol and 216 g of 37% formaldehyde were added, and the temperature was raised to 80 ° C for 2.5 h;

[0062] S4. Add 9.6 g of boric acid to the reaction mixture of step S3 and heat to 100 ° C for 1 h;

[0063] S5. The reaction mixture obtained in step S4 is evacuated to (-0.08) MPa for dehydration and then cooled, and 50% of the mass of phenol in methanol is added to obtain a modified phenolic resin.

[0064] Example 4

[0065] The preparation method of the modified phenolic resin of Example 4 comprises the following steps:

[0066] S1. Add 60g of water, 4.4g of 30% sodium hydroxide solution and 15g of enzymatic lignin into a three-necked flask, stir evenly, heat to 70°C for 1h, and then heat to 100°C for 1h;

[0067] S2. The reaction mixture of step S1 was cooled to 70°C, 120 g of phenol was added, and the temperature was raised to 90°C for 2 h;

[0068] S3. The reaction mixture of step S2 was cooled to 60 ° C, 36 g of cardanol and 168 g of 37% formaldehyde were added, and the temperature was raised to 100 ° C for 2 h;

[0069] S4. Add 22 g of boric acid to the reaction mixture in step S3 and heat to 100 ° C for 1.5 h;

[0070] S5. The reaction mixture obtained in step S4 is evacuated to (-0.08) MPa for dehydration and then cooled, and 50% of the mass of phenol in methanol is added to obtain a modified phenolic resin.

[0071] Comparative Example 1

[0072] The preparation method of the modified phenolic resin of Comparative Example 1 comprises the following steps:

[0073] S1. Add 60g of water, 4.4g of 30% sodium hydroxide solution and 6g of enzymatic lignin into a three-necked flask, stir evenly, heat to 70°C for 1h, and then heat to 100°C for 2h;

[0074] S2. The reaction mixture of step S1 was cooled to 70°C, 120 g of phenol was added, and the temperature was raised to 90°C for 1.5 h;

[0075] S3. The reaction mixture of step S2 was cooled to 60 ° C, 12 g of cardanol and 168 g of 37% formaldehyde were added, and the temperature was raised to 90 ° C for 2 h;

[0076] S4. Add 2 g of boric acid to the reaction mixture in step S3 and heat to 100 ° C for 1 h;

[0077] S5. The reaction mixture obtained in step S4 is evacuated to (-0.08) MPa for dehydration and then cooled, and 50% of the mass of phenol in methanol is added to obtain a modified phenolic resin.

[0078] Comparative Example 2

[0079] The preparation method of the modified phenolic resin of Comparative Example 2 comprises the following steps:

[0080] S1. Add 120 g of phenol, 10.6 g of 30% sodium hydroxide solution and 216 g of 37% formaldehyde into a three-necked flask, stir evenly, heat to 70 ° C for 0.5 h, and then heat to 100 ° C for 2 h;

[0081] S2. The reaction mixture of step S1 was cooled to 70 ° C, 66 g of cardanol was added, and the temperature was raised to 100 ° C for 2 h;

[0082] S3. The reaction mixture of step S2 was cooled to 60 ° C, 45 g of enzymatic lignin was added, and the temperature was raised to 80 ° C for 2.5 h;

[0083] S4. Add 9.6 g of boric acid to the reaction mixture of step S3 and heat to 100 ° C for 1 h;

[0084] S5. The reaction mixture obtained in step S4 is evacuated to (-0.08) MPa for dehydration and then cooled, and 50% of the mass of phenol in methanol is added to obtain a modified phenolic resin.

[0085] Comparative Example 3

[0086] The preparation method of the modified phenolic resin of Comparative Example 3 comprises the following steps:

[0087] S1. Add 60g of water, 4.4g of 30% sodium hydroxide solution and 15g of enzymatic lignin into a three-necked flask, stir evenly, heat to 70°C for 1h, and then heat to 100°C for 1h;

[0088] S2. The reaction mixture of step S1 was cooled to 70°C, 120 g of phenol was added, and the temperature was raised to 90°C for 2 h;

[0089] S3. The reaction mixture of step S2 was cooled to 60 ° C, 36 g of cardanol and 168 g of 37% formaldehyde were added, and the temperature was raised to 100 ° C for 2 h;

[0090] S4. Add 35 g of boric acid to the reaction mixture in step S3 and heat to 100 ° C for 1.5 h;

[0091] S5. The reaction mixture obtained in step S4 is evacuated to (-0.08) MPa, dehydrated, cooled, and methanol (50% of the mass of phenol) is added to obtain a modified phenolic resin.

[0092] Table 1 Performance of the pads made of modified phenolic resin in the examples and comparative examples

[0093]

[0094] It can be seen from the above experimental results that the pads made of phenolic resin modified with lignin, cardanol and boric acid prepared by the preparation method of the modified phenolic resin of Examples 1-4 have improved brittleness, improved bending strength, good punching performance, reduced warping and good flatness, wherein the bending strength is above 147 MPa, which can be beneficial to the subsequent processing operation of the pads, and the pads made of the modified phenolic resin of the present invention can ensure good heat resistance while improving various performances, and the pads can still maintain the same performance after being placed at 200°C for 30 minutes, and the present application also significantly reduces the cost of preparing modified phenolic resins by increasing the reaction participation amount of low-priced lignin in the system and introducing resins such as cardanol, and reduces environmental pollution by using lignin recycled materials, indicating that the preparation method of the modified phenolic resin of the present application also has good environmental benefits.

[0095] Comparative Examples 1 and 3 are compared with Example 4. The amounts of the modified components lignin, boric acid and cardanol added in Comparative Example 1 are not within the scope of the present invention, so that the modification effect of the phenolic resin is not obvious, and the toughness, flatness and punching properties of the prepared pad cannot be improved at the same time; too much boric acid is added in Comparative Example 3, so that the heat resistance of the pad prepared by the modified phenolic resin is significantly reduced; Comparative Example 2 is different from Example 3 in the steps of modifying the phenolic resin, which makes it impossible for the components to cooperate with each other to improve the performance of the phenolic resin. The above comparative examples cannot improve the various properties of the modified phenolic resin without affecting the heat resistance, and the prepared pad cannot have high flatness, excellent punching property, toughness and heat resistance at the same time.

[0096] Based on the test data of bending strength, heat resistance, punching property and warping of the pad made of modified phenolic resin in Table 1, the phenolic resin is modified by the preparation method of Examples 1-4. The modified phenolic resin prepared has obvious advantages over the control example in various properties when used in drilling pads, and can effectively meet the high standards of customers and the market.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a modified phenolic resin, characterized in that: The steps include: S1. Mix water, lignin and alkaline catalyst in a reactor and react for 1-3h; S2. Add phenol to the reaction mixture of step S1 and continue the reaction for 1-2h; S3. Add cardanol and aldehyde to the reaction mixture of step S2 and react for 1.5-3h; S4. Add boric acid to the reaction mixture of step S3 and react for 0.5-2h; S5. After vacuum dehydration, methanol is added to the reaction mixture obtained in step S4 to prepare a resin solution, thereby obtaining the modified phenolic resin.

2. The preparation method according to claim 1, characterized in that: The lignin is any one or more of enzymatically hydrolyzed lignin, lignin sulfonate, alkali lignin or high-boiling alcohol lignin.

3. The preparation method according to claim 1, characterized in that: The phenol is any one or more of phenol, nonylphenol, cresol, xylenol, bisphenol A or resorcinol.

4. The preparation method according to claim 1, characterized in that: The aldehyde is any one or more of formaldehyde solution, acetaldehyde, butyraldehyde or paraformaldehyde.

5. The preparation method according to claim 1, characterized in that: The alkaline catalyst is any one or more of ammonia water, methylamine, ethylamine, ethylenediamine, triethylamine, sodium hydroxide solution or barium hydroxide.

6. The preparation method according to claim 1, characterized in that: The amount of the alkaline catalyst used is 2-9% of the mass of the phenol.

7. The preparation method according to claim 1, characterized in that: The mass ratio of the phenol, water, lignin, cardanol, boric acid and aldehyde is: (98-102): (48-52): (10-40): (20-60): (5-20): (100-260).

8. The preparation method according to claim 1, characterized in that: The steps include: S1. Mix water, lignin and alkaline catalyst in a reactor, heat to 60-80°C for reaction for 0.5-1h, and then heat to 90-100°C for reaction for 1-2h; S2. The reaction mixture of step S1 is cooled to 60-80°C, phenol is added, and the temperature is raised to 90-100°C and the reaction is continued for 1-2h; S3. The reaction mixture of step S2 is cooled to 60-80 ° C, cardanol and aldehyde are added, and the reaction is carried out at a temperature of 80-100 ° C for 1.5-3h; S4. Add boric acid to the reaction mixture of step S3 and react at 90-110° C. for 0.5-2 h; S5. The reaction mixture obtained in step S4 is vacuum-dehydrated and then cooled, and methanol is added to prepare a resin solution to obtain the modified phenolic resin.

9. The modified phenolic resin obtained by the preparation method according to any one of claims 1 to 7.

10. Use of the modified phenolic resin according to claim 9 in preparing a drilling pad.

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