A preparation method of modified phenolic resin for PS plate photosensitive adhesive

Abstract

The invention discloses a preparation method of a modified phenolic resin for PS plate photosensitive adhesive, relating to the technical field of polymer materials. The invention aims to solve the problem of unstable reaction of thermosetting linear phenolic resin, wherein an oxalic acid catalyst is added in three steps, and the nodes of the oxalic acid catalyst addition and the reaction time in different temperature ranges are strictly controlled. The method comprises the following steps: S1, feeding: according to the process ratio, m-paracresol and formaldehyde aqueous solution are sequentially pumped into a reactor by a vacuum weight loss method, and an oxalic acid catalyst is added for the first time to prepare a base; S2, heating polycondensation reaction: heat transfer oil is injected into the interlayer of the reactor to start heating, and when the temperature is at three stages of 50-70°C, 70-80°C and 80-100°C, the reaction time of each stage is controlled within 160 minutes, and when the temperature rises to 100°C, the oxalic acid catalyst is added for the second time, and after an interval of 1 hour, the oxalic acid catalyst is added for the third time.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to a method for preparing a modified phenolic resin for PS plate photosensitive adhesive. Background Art

[0002] In the printing industry, PS plate photosensitive adhesive plays a vital role in printing quality. Modified phenolic resin, as the key film-forming resin in PS plate photosensitive adhesive, has a direct impact on the final quality and presentation of the print. As the printing industry continues to move towards higher precision and higher quality, the quality stability of modified phenolic resin has become more stringent.

[0003] However, the production difficulties of modified phenolic resins are prominent, and the core lies in the poor stability of the production process. From the perspective of raw materials, the supply of cresol and formaldehyde is complex, and the purity, impurities and chemical activity of different batches vary greatly. When the impurities exceed the standard, the polycondensation reaction is disturbed, the speed is abnormal, and side reactions occur frequently, affecting the quality and efficiency of the synthesis. In terms of the environment, the temperature of the production environment fluctuates due to seasons, day and night, and equipment thermal effects. Increasing the temperature causes the polycondensation reaction to overspeed and become difficult to control, and the molecular structure and performance of the product are damaged; cooling the temperature will delay the reaction, resulting in a long production cycle and high costs.

[0004] The interplay of raw materials and environmental factors leads to unstable reaction rates, resulting in unstable resin viscosity and melting point indicators. This results in poor quality consistency and reliability, making it difficult to meet the demands of high-end printing. Subsequent processing into photosensitive adhesives and printing plate preparation is also prone to degradation, such as molding defects, reduced resolution, and press run. This severely hinders the large-scale industrial production and industry expansion of modified phenolic resins, necessitating an effective solution to improve production stability and product quality. Summary of the Invention

[0005] In order to solve the above problems, that is, to solve the problems raised by the above background technology, the present invention proposes a preparation method of modified phenolic resin for PS plate photosensitive adhesive, which includes adding oxalic acid catalyst three times, strictly controlling the nodes of adding oxalic acid catalyst in batches and the reaction time in different temperature ranges, and includes the following steps: S1, feeding: according to the process ratio, vacuum weight loss method is used to sequentially pump m-cresol and formaldehyde aqueous solution into the reactor, and at the same time, oxalic acid catalyst is added for the first time to make a base; S2, heating polycondensation reaction: heat transfer oil is injected into the interlayer of the reactor to start heating, and when the temperature is between 50-70°C, the reaction mixture is heated to 100°C and ... , 70-80℃ and 80-100℃, the reaction time of each section is controlled within 160min. When the temperature rises to 100℃, oxalic acid catalyst is added for the second time. After an interval of 1h, oxalic acid catalyst is added for the third time. The liquid temperature in the kettle is kept at 100℃ for 3h; S3, dehydration: heating for dehydration; S4, dephenolization: start the vacuum pump for dephenolization; S5, central control: observe the dephenolization process in the sight glass, and the excess phenol fraction that does not participate in the reaction will not be removed until it stops. Sampling is sent to the laboratory for central control testing of viscosity and melting point. After passing the test, the material is discharged to obtain thermosetting linear phenolic resin.

[0006] The present invention is further configured as follows: the chemical reaction formula of the thermosetting linear phenolic resin is as follows:

[0007]

[0008] The present invention is further configured such that the weight ratio of the oxalic acid catalyst used three times is 1:1.2:1.2.

[0009] The present invention is further configured as follows: in S3, the dehydration temperature range is 220±10° C., and the reaction time range is 6-8 hours.

[0010] The present invention is further configured as follows: in S4, the dephenolization temperature range is 160±10° C., and the reaction time range is 2-3 h.

[0011] The present invention is further configured as follows: in said S5, the viscosity range of the thermosetting linear phenolic resin is 8.18-8.30 mm 2 / s, melting point range is 120-126℃.

[0012] The present invention is further configured as follows: the raw materials are composed of the following components by weight: 62.5%-63.5% of m-paracresol, 35.5%-37.5% of formaldehyde aqueous solution and 0.3%-0.5% of oxalic acid catalyst.

[0013] The present invention is further configured as follows: the concentration range of the formaldehyde aqueous solution is 36.5%-37.5%.

[0014] The beneficial technical effects of the present invention are as follows: the modified phenolic resin of the present invention has a stable reaction and the viscosity of the obtained product is between 8.18-8.30 mm 2 / s, with melting points ranging from 120-126°C. During the synthesis stage, oxalic acid catalyst is added in three separate additions. Strict control of the timing of each addition and the reaction time at different temperature ranges ensures a smooth reaction during the production process and easier control of the reaction time. Setting the holding time to 3 hours and the holding temperature to 100°C maximizes the complete reaction of the phenolic formaldehyde, resulting in a high-weight product with minimal byproducts, high yield, and exceptional stability. PS plate photosensitive adhesives made with modified phenolic resins offer fast photosensitivity, high resolution, and increased print run rates. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Shown is a process flow chart of the present invention. DETAILED DESCRIPTION

[0016] Please refer to the attached Figure 1 It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0017] The test index requirements of the embodiments and comparative examples of the present invention are: viscosity 8.18-8.30mm 2 / s, melting point 120-126℃, the PS plate photosensitive adhesive made of modified phenolic resin within this viscosity and melting point range has fast photosensitivity, high resolution, and increased printing durability, which is within the ideal product indicator range.

[0018] Example 1

[0019] Batch number: 2023-174.

[0020] S1. Feeding: According to the process ratio, 600 kg of m-p-cresol and 350 kg of 36.5% formaldehyde solution were pumped into the reactor in sequence by vacuum weight loss method, and 1.15 kg of oxalic acid catalyst was added through the manhole for the first time as a base;

[0021] S2, heating polycondensation reaction: inject heat transfer oil into the reactor interlayer to start heating, and monitor the reaction time of the temperature in the reactor in real time:

[0022] 9:00 The temperature of the liquid in the kettle is 50°C;

[0023] 10:20 The temperature of the liquid in the kettle is 60°C;

[0024] 11: The temperature of the liquid in the 40 kettle is 70°C;

[0025] 14:20 The temperature of the liquid in the kettle is 80°C;

[0026] At 17:00, the temperature of the liquid in the kettle reached 100°C. At this time, 1.38 kg of oxalic acid catalyst was added from the manhole for the second time. After an interval of 1 hour,

[0027] At 18:00, 1.38 kg of oxalic acid catalyst was added from the manhole for the third time, and the liquid temperature in the kettle was kept at 100°C and refluxed for 3 hours;

[0028] S3, 21:00 dehydration: heating to 210℃, dehydration for 8h, removing 220kg of acidic phenolic process wastewater;

[0029] S4, dephenolization at 5:00 the next day: start the vacuum pump for dephenolization, cool to 160°C, and dephenolize for 2 hours;

[0030] S5, 8:30 Central Control: Observe the dephenolization process in the sight glass, and the excess phenol fraction that does not participate in the reaction will no longer be removed. At 9:30, take a sample and send it to the laboratory for central control to test the product viscosity and melting point index: viscosity 8.21mm 2 / s, melting point 121 ℃, detection indicators meet the standards, 11:00 discharge, cooling, crushing, packaging, storage, to obtain thermosetting linear phenolic resin, product weight 560kg, yield 93.3%, kettle residue 170kg.

[0031] Example 2

[0032] Batch number: 2024-136.

[0033] S1. Feeding: According to the process ratio, 600 kg of m-p-cresol and 350 kg of 36.5% formaldehyde solution were pumped into the reactor in sequence by vacuum weight loss method, and 1.15 kg of oxalic acid catalyst was added through the manhole for the first time as a base;

[0034] S2, heating polycondensation reaction: inject heat transfer oil into the reactor interlayer to start heating, and monitor the reaction time of the temperature in the reactor in real time:

[0035] 9:20 The temperature of the liquid in the kettle is 50°C;

[0036] 10: The temperature of the liquid in the 40 kettle is 60°C;

[0037] 12:00 The temperature of the liquid in the kettle is 70°C;

[0038] 14:40 The temperature of the liquid in the kettle is 80°C;

[0039] At 17:20, the temperature of the liquid in the kettle reached 100°C. At this time, 1.38 kg of oxalic acid catalyst was added from the manhole for the second time. After an interval of 1 hour,

[0040] At 18:20, 1.38 kg of oxalic acid catalyst was added from the manhole for the third time, and the liquid in the kettle was refluxed and kept warm for 3 hours at a temperature of 100°C.

[0041] S3, 21:20 Dehydration: Heat to 210℃, dehydrate for 8h, and remove 219kg of acidic phenolic process wastewater;

[0042] S4, dephenolization at 5:20 the next day: start the vacuum pump to dephenolize, cool to 160℃, and dephenolize for 2h;

[0043] S5, 8:50 Central Control: Observe the dephenolization process in the sight glass, and the excess phenol fraction that does not participate in the reaction will no longer be removed. At 9:50, take a sample and send it to the laboratory for central control to test the product viscosity and melting point index: viscosity 8.25mm 2 / s, melting point 123℃, detection indicators meet the standards, discharge at 11:20, cooling, crushing, packaging, storage, to obtain thermosetting linear phenolic resin, product weight 562kg, yield 93.7%, kettle residue 169kg.

[0044] Example 3

[0045] Batch number: 2024-180.

[0046] S1. Feeding: According to the process ratio, 600 kg of m-p-cresol and 350 kg of 36.5% formaldehyde solution were pumped into the reactor in sequence by vacuum weight loss method, and 1.15 kg of oxalic acid catalyst was added through the manhole for the first time as a base;

[0047] S2, heating polycondensation reaction: inject heat transfer oil into the reactor interlayer to start heating, and monitor the reaction time of the temperature in the reactor in real time:

[0048] 8: 20 The temperature of the liquid in the kettle is 50°C;

[0049] 9: The temperature of the liquid in the 40 kettle is 60°C;

[0050] 11:00 The temperature of the liquid in the kettle is 70°C;

[0051] 13: The temperature of the liquid in the 40 kettle is 80°C;

[0052] At 16:20, the temperature of the liquid in the kettle reached 100°C. At this time, 1.38 kg of oxalic acid catalyst was added from the manhole for the second time. After an interval of 1 hour,

[0053] At 17:20, 1.38 kg of oxalic acid catalyst was added from the manhole for the third time, and the liquid in the kettle was refluxed and kept warm for 3 hours at a temperature of 100°C.

[0054] S3, 20:20 dehydration: heating to 210℃, dehydration for 8h, removing 221kg of acidic phenolic process wastewater;

[0055] S4, dephenolization at 4:20 the next day: start the vacuum pump to dephenolize, cool to 160℃, and dephenolize for 2h;

[0056] S5, 7:50 Central Control: Observe the dephenolization process in the sight glass, and the excess phenol fraction that does not participate in the reaction will no longer be removed. At 8:50, take a sample and send it to the laboratory for central control to test the product viscosity and melting point index: viscosity 8.20mm 2 / s, melting point 120℃, detection indicators meet the standards, discharge at 10:20, cooling, crushing, packaging, storage, to obtain thermosetting linear phenolic resin, product weight 558kg, yield 93%, kettle residue 171kg.

[0057] Comparative Example 1

[0058] Reaction conditions: catalyst was added at once, holding time was 3 h, holding temperature was 100 °C.

[0059] S1. Feeding: According to the process ratio, 600 kg of m-p-cresol and 350 kg of 36.5% formaldehyde solution were pumped into the reactor in sequence by vacuum weight loss method, and 3.91 kg of oxalic acid catalyst was added at one time through the manhole;

[0060] S2, heating polycondensation reaction: inject heat transfer oil into the reactor interlayer to start heating, and monitor the reaction time of the temperature in the reactor in real time:

[0061] 9:00 The temperature of the liquid in the kettle is 50°C;

[0062] 10:10 The temperature of the liquid in the kettle is 60°C;

[0063] 11:10 The temperature of the liquid in the kettle is 70°C;

[0064] 13:20 The temperature of the liquid in the kettle is 80°C;

[0065] At 16:00, the temperature of the liquid in the kettle reached 100°C and was kept at reflux for 3 hours;

[0066] S3, 19:00 Dehydration: The temperature was raised to 210℃. During the dehydration process, the power was greater than 15KW. Stirring was stopped. As the temperature gradually increased, the coagulated liquid gradually melted. Stirring was restarted. The dehydration was continued for 8 hours. 226kg of acidic phenolic process wastewater was removed.

[0067] S4, dephenolization at 3:00 the next day: start the vacuum pump for dephenolization, cool to 160°C, and dephenolize for 2 hours;

[0068] S5, 8:30 Central Control: Observe the dephenolization process in the sight glass, and the excess phenol fraction that does not participate in the reaction will no longer be removed. At 9:30, take a sample and send it to the laboratory for central control to test the product viscosity and melting point index: viscosity 8.52mm 2 / s, melting point 128℃, the test indicators do not meet the standards, marked as unqualified product, product weight 544kg, yield 90.7%, kettle residue 180kg.

[0069] Comparative Example 2

[0070] Reaction conditions: the catalyst was added in two portions, the holding time was 3 h, and the holding temperature was 100°C.

[0071] S1. Feeding: According to the process ratio, 600 kg of m-p-cresol and 350 kg of 36.5% formaldehyde solution were pumped into the reactor in sequence by vacuum weight loss method, and 1.15 kg of oxalic acid catalyst was added through the manhole for the first time as a base;

[0072] S2, heating polycondensation reaction: inject heat transfer oil into the reactor interlayer to start heating, and monitor the reaction time of the temperature in the reactor in real time:

[0073] 9:20 The temperature of the liquid in the kettle is 50°C;

[0074] 10: The temperature of the liquid in the 40 kettle is 60°C;

[0075] 12:00 The temperature of the liquid in the kettle is 70°C;

[0076] 14:40 The temperature of the liquid in the kettle is 80°C;

[0077] At 17:20, the temperature of the liquid in the kettle reached 100°C. At this time, 2.76 kg of oxalic acid catalyst was added from the manhole for the second time. The reaction was intense and the liquid level in the kettle rose to the sight glass. The liquid in the kettle was refluxed and kept warm for 3 hours at a temperature of 100°C.

[0078] S3, 20:20 dehydration: heating to 210℃, dehydration for 10h, removing 224kg of acidic phenolic process wastewater;

[0079] S4, dephenolization at 6:20 the next day: start the vacuum pump to dephenolize, cool to 160℃, and dephenolize for 3 hours;

[0080] S5, 9:20 Central Control: Observe the dephenolization process in the sight glass, and the excess phenol fraction that does not participate in the reaction will no longer be removed. At 10:20, take a sample and send it to the laboratory for central control to test the product viscosity and melting point index: viscosity 7.92mm 2 / s, melting point 119℃, detection indexes meet the standards, material was discharged at 11:20, cooled, crushed, packaged and stored, and a thermosetting linear phenolic resin was obtained, with a product weight of 551kg, a yield of 91.8%, and 175kg of residual liquid in the kettle.

[0081] Comparative Example 3

[0082] Reaction conditions: the catalyst was added in three times, the holding time was 2 h, and the holding temperature was 90 °C.

[0083] S1. Feeding: According to the process ratio, 600 kg of m-p-cresol and 350 kg of 36.5% formaldehyde solution were pumped into the reactor in sequence by vacuum weight loss method, and 1.15 kg of oxalic acid catalyst was added through the manhole for the first time as a base;

[0084] S2, heating polycondensation reaction: inject heat transfer oil into the reactor interlayer to start heating, and monitor the reaction time of the temperature in the reactor in real time:

[0085] 8: 20 The temperature of the liquid in the kettle is 50°C;

[0086] 9: The temperature of the liquid in the 40 kettle is 60°C;

[0087] 11:00 The temperature of the liquid in the kettle is 70°C;

[0088] 13: The temperature of the liquid in the 40 kettle is 80°C;

[0089] At 15:20, the temperature of the liquid in the kettle reached 90°C. At this time, 1.38 kg of oxalic acid catalyst was added from the manhole for the second time. After an interval of 1 hour,

[0090] At 16:20, 1.38 kg of oxalic acid catalyst was added from the manhole for the third time, and the liquid in the kettle was refluxed and kept warm for 2 hours at a temperature of 90°C.

[0091] S3, 18:20 Dehydration: Heat to 210℃, dehydrate for 9.5h, and remove 220kg of acidic phenolic process wastewater;

[0092] S4, dephenolization at 3:50 the next day: start the vacuum pump to dephenolize, cool to 160°C, and dephenolize for 3 hours;

[0093] S5, 6:50 Central Control: Observe the dephenolization process in the sight glass. When the excess phenol fraction that does not participate in the reaction stops coming out, take a sample and send it to the laboratory for central control to test the product viscosity and melting point. The viscosity is 7.68mm. 2 / s, melting point 108℃, the test indicators do not meet the standards, marked as unqualified product, product weight 520kg, yield 86.7%, kettle residue 210kg.

[0094] Table 1 Product performance test data

[0095]

[0096] Comparative Example 1: Oxalic acid catalyst was added once. During the production process, the reaction was intense at 50-80°C. It was extremely difficult to control the reaction time of each section. The temperature of the material in the kettle rose sharply. During the dehydration process, the viscosity of the material was large and the stirring operation had to be stopped. The viscosity was detected to be 8.52 mm. 2 / s, the melting point is 128℃, the indicators deviate greatly from the ideal range, the stability of the oxalic acid catalyst is poor after one-time investment, the production process is difficult to control, the indicators deviate greatly, there are many by-products, and the yield is low.

[0097] Comparative Example 2: Oxalic acid catalyst was added twice. After the second addition of catalyst, the reaction in the kettle was intense, and the liquid level in the kettle rose to the sight glass, which was very dangerous and difficult to control. The subsequent dehydration and dephenolization stages were difficult to control, and the viscosity was 7.92 mm. 2 / s, the melting point is 119℃, the index is low and still cannot meet the ideal index requirements, and there are many by-products and the yield is low.

[0098] Comparative Example 3: Oxalic acid catalyst was added three times, the holding time was shortened to 2 hours, and the holding temperature was set to 90°C. Due to the poor holding time and temperature, the aqueous solution of m-cresol and formaldehyde could not fully react, and the viscosity was detected to be 7.68 mm. 2 / s, with a melting point of 108°C, it is still an unqualified product, with more by-products and a low yield.

[0099] It can be seen that the oxalic acid catalyst in Examples 1-3 is added three times, and the nodes of the oxalic acid catalyst being added in batches and the reaction time in different temperature ranges are strictly controlled, which can ensure a smooth reaction in the production process and make the reaction time easier to control. The holding time is set to 3h and the holding temperature is set to 100°C, which can ensure that the phenolic formaldehyde is fully reacted to the maximum extent, and the obtained product has a large weight, few by-products, a high yield, and extremely high stability, providing a highly stable resin raw material for PS plate photosensitive adhesive.

[0100] Product inspection equipment and manufacturer model

[0101]

[0102] Since the test values such as viscosity, melting point and weight are all obtained by manual transcription from reading instruments and equipment, it is impossible to issue an electronic version of the relevant test certificate report.

[0103] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and equivalent components may be substituted without departing from the scope of the present invention. In particular, the various technical features described in the various embodiments may be combined in any manner as long as no structural conflicts exist. The present invention is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

[0104] In the description of the present invention, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. These are intended solely for ease of description and are not intended to indicate or imply that the device or component described must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not intended to indicate or imply relative importance.

[0105] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0106] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion, such that a process, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed or inherent to such process, article, or apparatus / device.

[0107] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A method for preparing a modified phenolic resin for PS plate photosensitive adhesive, characterized in that: The raw materials are composed of the following components by weight: 62.5%-63.5% of m-paracresol, 35.5%-37.5% of formaldehyde aqueous solution, and 0.3%-0.5% of oxalic acid catalyst; the concentration range of the formaldehyde aqueous solution is 36.5%-37.5%; the oxalic acid catalyst is added three times, and the weight ratio of the three times is 1:1.2:1.

2. The points of adding the oxalic acid catalyst in batches and the reaction time in different temperature ranges are strictly controlled, including the following steps: S1. Feeding: According to the process ratio, m-p-cresol and formaldehyde aqueous solution are pumped into the reactor in sequence by vacuum weight loss method, and oxalic acid catalyst is added for the first time as a base; S2, temperature-raising polycondensation reaction: heat transfer oil is injected into the interlayer of the reactor to start heating. When the temperature is in the three stages of 50-70°C, 70-80°C and 80-100°C, the reaction time of each stage is controlled within 160 minutes. When the temperature rises to 100°C, oxalic acid catalyst is added for the second time. After an interval of 1 hour, oxalic acid catalyst is added for the third time. The liquid temperature in the reactor is refluxed and kept warm for 3 hours at 100°C. S3, dehydration: heating and dehydration; S4, dephenolization: start the vacuum pump to dephenolize; S5. Central control: During the dephenolization process, observe the sight glass until the excess phenol fraction that has not participated in the reaction is no longer removed. Take a sample and send it to the laboratory for central control testing of viscosity and melting point. After passing the test, discharge the material to obtain thermosetting linear phenolic resin.

2. The method for preparing a modified phenolic resin for PS plate photosensitive adhesive according to claim 1, wherein: In the step S3, the dehydration temperature range is 220±10° C., and the reaction time range is 6-8 h.

3. The method for preparing a modified phenolic resin for PS plate photosensitive adhesive according to claim 1, wherein: In the step S4, the dephenolization temperature range is 160±10° C., and the reaction time range is 2-3 h.

4. The method for preparing a modified phenolic resin for PS plate photosensitive adhesive according to claim 1, wherein: In the S5, the viscosity of the thermosetting linear phenolic resin is in the range of 8.18-8.30 mm 2 / s, melting point range is 120-126℃.

5. A modified phenolic resin for PS plate photosensitive adhesive prepared according to the method of claim 1.

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