Modified MQ resin and preparation method and application thereof

Abstract

The invention discloses modified MQ resin as well as a preparation method and application thereof. According to the modified MQ resin, the molecular expression general formula is expressed as M0.75 (QP) x (QOH) yQz by taking the amount of M chain links as 0.75, in the formula, x / y = 0.5-5. The resin synthesis method comprises two steps of grading the MQ resin and synthesizing the modified MQ resin. By grading the MQ resin, the fogging problem in the preparation process of the pressure-sensitive adhesive can be improved. When the modified resin is applied to preparation and synthesis of the pressure-sensitive adhesive, the initial adhesion of the pressure-sensitive adhesive can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of the synthesis of MQ resin. More specifically, it relates to a modified MQ resin, a preparation method thereof, and an application thereof. Background Art

[0002] Organic silicone resin products have many excellent properties, including resistance to high and low temperatures, resistance to weather aging, water repellency, moisture proofing, high insulation strength, low dielectric loss, arc resistance, radiation resistance, etc., and are widely used in industries such as national defense and military, electrical industry, leather industry, light industrial products, rubber and plastics, food hygiene, etc. As a type of organic silicone resin, MQ resin is composed of monofunctional siloxane units (M group: R3SiO 1 / 2 ) and tetrafunctional siloxane units (Q group: SiO 4 / 2 ) and is mainly applied to fields such as pressure-sensitive adhesives.

[0003] In recent years, with the continuous increase in the demand for organosilicon pressure-sensitive adhesives, their production and sales scales have increased significantly. With the intensification of market competition, higher requirements have also been placed on the properties such as the appearance and initial adhesion of organosilicon pressure-sensitive adhesives. Organosilicon pressure-sensitive adhesives mainly consist of polysiloxane elastomers, MQ resins, catalysts, and additives. For hydrosilylation-cured pressure-sensitive adhesives, when the proportion of MQ resin macromolecules is relatively high, it will cause the glue mixing to become foggy and at the same time affect the properties such as the initial adhesion of the pressure-sensitive adhesive. Therefore, the key to improving the application performance of the pressure-sensitive adhesive lies in the MQ resin.

[0004] CN109438709A discloses a method for preparing MQ resin by an intermittent method. By replacing toluene with a high-purity hydrocarbon solvent, a resin with a narrow molecular weight distribution can be obtained. At the same time, by changing the reaction temperature, reaction time of the aqueous sodium silicate solution and acid, and the concentration of hydrochloric acid, a methyl MQ resin with a molecular weight greater than 10000 g / mol is obtained. CN109553773A discloses a method for preparing methyl MQ resin. By refining the aqueous sodium silicate solution with an organic solvent, the prepared methyl MQ resin can have a higher molecular weight and a narrower molecular weight distribution. CN113321809A discloses a continuous preparation method of MQ resin with a narrow molecular weight distribution. The continuous mixing of hydrochloric acid and water glass is completed through a static mixer, and further, a tubular aging reactor is used to ensure the narrow molecular weight distribution of the product.

[0005] The above documents provide methods for intermittently or continuously producing MQ resin with a narrow molecular weight distribution by the water glass method. However, the water glass method has high reaction activity. When changing the reaction conditions to increase the molecular weight of the MQ resin, the molecular weight distribution will become relatively wider. When the proportion of MQ resin macromolecules is relatively high, it will cause the glue mixing to become foggy, which will inevitably affect the application performance of the MQ resin. Summary of the Invention

[0006] To solve the problems of fogging of MQ resin in pressure-sensitive adhesives and improving the application performance of MQ resin, the present invention provides a modified MQ resin, its preparation method and application. By the preparation method provided by the present invention, the proportion of macromolecules in MQ resin can be effectively reduced. The present invention reduces the solubility of MQ resin by adding a poor solvent, so that the macromolecular part of MQ resin precipitates and separates. At the same time, by modifying MQ resin, the appearance of the pressure-sensitive adhesive is effectively improved and its application performance in the pressure-sensitive adhesive is enhanced.

[0007] To achieve the above object, the present invention is realized through the following technical solutions:

[0008] A modified MQ resin, with the amount of M linkages being 0.75, the molecular expression general formula is expressed as: M 0.75 (Q P ) x (Q OH ) y Q z ; In the formula, x / y = 0.5 to 5; x + y + z = 1;

[0009] The structural expression of the M linkage in the molecular expression general formula is formula (I):

[0010]

[0011] The Q P linkage in the molecular expression general formula has a structural expression of formula (II):

[0012]

[0013] In formula (II), the value of p is an integer from 10 to 80, such as 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 72, 80, etc., preferably an integer from 10 to 40, more preferably an integer from 20 to 40;

[0014] The Q OH linkage in the molecular expression general formula has a structural expression of formula (III):

[0015]

[0016] The structural expression of the Q linkage in the molecular expression general formula is formula (IV):

[0017]

[0018] In some specific implementation schemes, in the molecular expression general formula, x = 0.05 to 0.17, y = 0.03 to 0.12; z = 0.67 to 0.87.

[0019] On the other hand, the present invention also provides a method for preparing a modified MQ resin, comprising the following steps:

[0020] (1) Synthesize methyl MQ resin. Preferably, the molecular weight Mw of the methyl MQ resin is 18,000 - 19,500, and the hydroxyl content is 2 - 4 wt%.

[0021] (2) Dissolve the methyl MQ resin and an aromatic hydrocarbon solvent at a certain temperature, keep stirring, add a poor solvent and mix well, then let it stand for fractionation. Remove the macromolecular resin precipitated in the lower layer, and rotary evaporate the upper solution to obtain an MQ resin powder with a lower macromolecular content.

[0022] (3) After fully dissolving the fractionated MQ resin and the aromatic hydrocarbon solvent, add hydroxyl silicone oil and an acid catalyst for the next reaction. After the reaction is completed, neutralize the acid with a neutralizing agent, and filter to obtain the modified MQ resin.

[0023] The present invention has no particular limitation on the preparation method of methyl MQ resin. For example, the methyl MQ resin can be synthesized with reference to Example 3 of Patent CN114230795A, with a molecular weight Mw of 18,565 and a hydroxyl content of 3 wt%.

[0024] In some specific embodiments, in step (2), the aromatic hydrocarbon solvent is one or more selected from benzene, toluene, and xylene, preferably xylene. The poor solvent is one or more selected from acetonitrile, methanol, acetone, ethyl acetate, and n-butanol, preferably acetonitrile. The mass ratio of the methyl MQ resin, the aromatic hydrocarbon solvent, and the poor solvent is 1:(0.4 - 2.5):(0.01 - 0.5), preferably 1:(0.4 - 1):(0.05 - 0.1).

[0025] In some specific embodiments, in step (2), the dissolution temperature is 25 - 80°C, preferably 40 - 70°C; the dissolution time is 0.5 - 2 h.

[0026] In some specific embodiments, in step (2), the stirring speed is 50 - 200 revolutions / min, and the stirring time is 0.5 - 3 h.

[0027] In some specific embodiments, in step (2), the temperature for standing and fractionation is 25 - 80°C, the standing and fractionation time is 0.5 - 3 h, preferably 1 h.

[0028] In some specific embodiments, in step (2), the rotary evaporation temperature is 80 - 120°C, preferably 100 - 120°C, the rotary evaporation pressure is 0 - 10 mbar, preferably 0 - 5 mbar, and the rotary evaporation speed is 40 - 60 rpm, preferably 60 rpm.

[0029] In some specific embodiments, in step (2), the proportion of macromolecules (Mw > 60,000) in the MQ resin is less than 3 wt%, preferably less than 2 wt%.

[0030] In some specific embodiments, in step (3), the aromatic hydrocarbon solvent is one or more selected from benzene, toluene, and xylene, preferably xylene. The hydroxy silicone oil is an alcohol hydroxy mono-capped silicone oil. The acid catalyst is one or more selected from trifluoromethanesulfonic acid and trifluoroacetic acid, preferably trifluoromethanesulfonic acid. The mass ratio of the modified MQ resin, aromatic hydrocarbon solvent, hydroxy silicone oil, and acid catalyst is 1:(0.6 - 1):(0.4 - 0.8):(0.01 - 0.05).

[0031] In some specific embodiments, in step (3), the reaction temperature is 70 - 120 °C and the reaction time is 2 - 5 h.

[0032] In some specific embodiments, in step (3), the neutralizing agent is calcium carbonate or sodium bicarbonate, and the amount of the neutralizing agent is 5 - 10 times the mass of the acid catalyst.

[0033] On the other hand, the application of the aforementioned modified MQ resin or the modified MQ resin prepared by the aforementioned preparation method in a pressure-sensitive adhesive.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] (1) The present invention uses a poor solvent to fractionate the MQ resin, effectively reducing the content of ultra-large molecules (Mw > 60,000) in the MQ resin, and effectively solving the problem of fogging of the MQ resin in the pressure-sensitive adhesive.

[0036] (2) The modified MQ resin prepared by the present invention is added to the pressure-sensitive adhesive system. While achieving a tackifying effect, it has better initial tack and effectively improves the application performance of the pressure-sensitive adhesive. Detailed Embodiments

[0037] The following will describe the embodiments of the present invention in detail. Those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention.

[0038] For those not specified in the examples in terms of specific techniques or conditions, they shall be carried out according to the techniques or conditions described in the literature in this field or according to the product specifications. For reagents or instruments not specified in terms of the manufacturer, they are conventional products that can be obtained through market purchase. Unless otherwise stated, the scientific and technical terms used in the present invention have the meanings commonly understood by those skilled in the art. And the (laboratory) operation steps used herein are all conventional steps widely used in the corresponding field.

[0039] Raw material source

[0040] Methyl MQ resin: The molecular weight Mw is 18565, the proportion of macromolecules (Mw > 60,000) is 4.1%, and the hydroxyl content is 3 wt%. It was synthesized according to Example 3 of Patent CN114230795A. The specific method is as follows:

[0041] At 30 °C, in reactor A, 36 wt% hydrochloric acid aqueous solution and 25 wt% sodium silicate solution were continuously added at flow rates of 300 g / min and 1495 g / min respectively, and the SiO2 / HCl ratio was 1.59. The power equipment in reactor A was a peristaltic pump, and the mixing equipment was an SX type static mixer. The average residence time was 3 min, the pH value was 2, and the reflux ratio was 15. The aging time in reactor B was 6 min, and reactor B was a tubular reactor. All the products in reactor B, ethanol, and hexamethyldisilane were continuously added to reactor C at 550 g / min, 85 g / min, and 750 g / min respectively. The reaction temperature in reactor C was 70 °C, and the capping reaction time was 150 min. The product of reactor C continuously entered reactor D, and reactor D was washed and phase-separated for 50 min. Finally, the organic phase in reactor D was continuously fed into reactor E for rectification. The operating temperature was 155 °C, the operating pressure was atmospheric pressure, and low-boiling substances were removed after rectification to obtain an MQ resin solution.

[0042] Other experimental materials used in the following examples were all purchased from regular biochemical reagent stores.

[0043] Testing method

[0044] In the following examples, the molecular weight and its distribution were tested by gel permeation chromatography (GPC), using ethyl acetate as the mobile phase, and the GPC instrument model was Agilent 1260II GPC MDS. The specific testing method is as follows: The sample was dissolved in ethyl acetate, separated by gel chromatography, and the molecular weight and molecular weight distribution of the MQ resin sample were relatively corrected by making a standard curve with a standard PS (polystyrene).

[0045] Example 1

[0046] (1) Classification: 700 g of methyl MQ resin and 300 g of xylene were added to a three-necked flask equipped with a stirrer, thermometer, and condenser. The solution temperature was controlled at 50 °C, and the stirrer was turned on simultaneously at a speed of 80 revolutions / min. After stirring for 30 min, 50 g of acetonitrile was added, and after continuing to stir for 10 min, it was left to stand for classification for 60 min, and then the upper layer solution was taken out and rotary evaporated to obtain the classified MQ resin powder. At this time, the molecular weight Mw of the MQ resin was 17159, and the proportion of macromolecules (Mw > 60,000) was 2.1%.

[0047] (2) Synthesis of modified MQ resin: Add 500 g of fractionated MQ resin and 300 g of xylene into a three-necked flask equipped with a stirrer, a thermometer, and a condenser. Control the solution temperature at 50 °C and the rotation speed at 80 rpm. After stirring for 30 min, add 300 g of alcohol-hydroxyl mono-capped silicone oil (polymerization degree is 20) and 5 g of trifluoromethanesulfonic acid. After carrying out negative pressure reflux for water removal at 110 °C for 3 h, stop the reaction. Add 30 g of calcium carbonate for neutralization and filtration, and then obtain the modified MQ resin through rotary evaporation. The molecular weight Mw is 17562, and the proportion of macromolecules (Mw > 60,000) is 2.2%.

[0048] Example 2

[0049] (1) Fractionation: Add 600 g of methyl MQ resin and 600 g of toluene into a three-necked flask equipped with a stirrer, a thermometer, and a condenser. Control the solution temperature at 40 °C, and at the same time turn on the stirrer with a rotation speed of 100 rpm. After stirring for 20 min, add 40 g of methanol, continue stirring for 10 min, then let it stand for fractionation for 50 min, take out the upper layer solution, and obtain the fractionated MQ resin powder through rotary evaporation. At this time, the molecular weight Mw of the MQ resin is 16987, and the proportion of macromolecules (Mw > 60,000) is 1.9%.

[0050] (2) Synthesis of modified MQ resin: Add 500 g of fractionated MQ resin and 500 g of toluene into a three-necked flask equipped with a stirrer, a thermometer, and a condenser. Control the solution temperature at 70 °C and the rotation speed at 50 rpm. After stirring for 40 min, add 200 g of alcohol-hydroxyl mono-capped silicone oil (polymerization degree is 40) and 8 g of trifluoroacetic acid. After carrying out negative pressure reflux for water removal at 120 °C for 2 h, stop the reaction. Add 70 g of sodium bicarbonate for neutralization and filtration, and then obtain the modified MQ resin through rotary evaporation. The molecular weight Mw is 17322, and the proportion of macromolecules (Mw > 60,000) is 1.8%.

[0051] Example 3

[0052] (1) Fractionation: Add 700 g of methyl MQ resin and 300 g of benzene into a three-necked flask equipped with a stirrer, a thermometer, and a condenser. Control the solution temperature at 55 °C, and at the same time turn on the stirrer with a rotation speed of 70 rpm. After stirring for 30 min, add 65 g of ethyl acetate, continue stirring for 10 min, then let it stand for fractionation for 90 min, take out the upper layer solution, and obtain the fractionated MQ resin powder through rotary evaporation. At this time, the molecular weight Mw of the MQ resin is 17360, and the proportion of macromolecules (Mw > 60,000) is 2.3.

[0053] (2) Synthesis of modified MQ resin: Add 500 g of fractionated MQ resin and 500 g of benzene into a three-necked flask equipped with a stirrer, a thermometer, and a condenser. Control the solution temperature at 80 °C and the rotation speed at 80 rpm. After stirring for 30 min, add 400 g of alcohol-hydroxyl mono-capped silicone oil (polymerization degree of 25) and 15 g of trifluoromethanesulfonic acid. After carrying out negative pressure reflux for water removal at 100 °C for 3 h, stop the reaction. Add 80 g of calcium carbonate for neutralization and filtration, and then obtain the modified MQ resin through rotary evaporation. The molecular weight Mw is 17681, and the proportion of macromolecules (Mw > 60,000) is 2.3%.

[0054] Comparative Example 1

[0055] The methyl MQ resin is not subjected to fractionation treatment.

[0056] Synthesis of modified MQ resin: Add 500 g of unfractionated MQ resin and 300 g of xylene into a three-necked flask equipped with a stirrer, a thermometer, and a condenser. Control the solution temperature at 50 °C and the rotation speed at 80 rpm. After stirring for 30 min, add 300 g of alcohol-hydroxyl mono-capped silicone oil (polymerization degree of 20) and 5 g of trifluoromethanesulfonic acid. After carrying out negative pressure reflux for water removal at 110 °C for 3 h, stop the reaction. Add 30 g of calcium carbonate for neutralization and filtration, and then obtain the modified MQ resin through rotary evaporation. The molecular weight Mw is 18453, and the proportion of macromolecules (Mw > 60,000) is 4.2%.

[0057] Comparative Example 2

[0058] Fractionation: Add 700 g of methyl MQ resin and 300 g of xylene into a three-necked flask equipped with a stirrer, a thermometer, and a condenser. Control the solution temperature at 50 °C, and at the same time turn on the stirrer with a rotation speed of 80 rpm. After stirring for 30 min, add 50 g of acetonitrile, continue stirring for 10 min, then let it stand for fractionation for 60 min, and then take out the upper layer solution and obtain the fractionated MQ resin powder through rotary evaporation. At this time, the molecular weight Mw of the MQ resin is 17159, and the proportion of macromolecules (Mw > 60,000) is 2.1%.

[0059] The synthesis of modified MQ resin is not carried out.

[0060] Relevant performance tests

[0061] The finished products prepared from all the examples and comparative examples of the present invention are further formulated into adhesives for testing. The operation steps are as follows: Dissolve 800 g of MQ resin in 600 g of xylene, then add 500 g of vinyl raw rubber, 2.7 g of inhibitor (methylhexynol), and 7 g of hydrogen-containing silicone oil. After all the materials are dissolved into a homogeneous system, the pressure-sensitive adhesive for testing is obtained.

[0062] The blank control sample is a commercially available silicone pressure-sensitive adhesive (Dow Corning 7657, Dow Chemical). The fogging situation of the pressure-sensitive adhesive was observed by placing it in a transparent glass bottle respectively. The test method for the initial tack of the rolling ball refers to the national standard GB-T4852-2002, and the evaluation results are shown in Table 1.

[0063] Table 1 Performance test results of silicone pressure-sensitive adhesive

[0064]

[0065]

[0066] As can be seen from Table 1, after the MQ resin is subjected to fractional treatment, the appearance of the prepared pressure-sensitive adhesive changes from fogging to clear and transparent. By modifying the MQ resin, the initial tack of the rolling ball of the pressure-sensitive adhesive is effectively improved. In summary, by subjecting the MQ resin to fractional treatment and at the same time by modification, the appearance of the prepared pressure-sensitive adhesive is effectively improved, and the initial tack performance of the pressure-sensitive adhesive is improved.

[0067] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A modified MQ resin, characterized in that, The MQ resin, taking the amount of M linkages as 0.75, is represented by the general molecular formula: M 0.75 (Q P ) x (Q OH ) y Q z ; where x / y = 0.5 to 5; x + y + z = 1; The structural expression of the M segment in the molecular expression general formula is Formula (I): Q in the molecular expression general formula P The structural expression of the chain link is Formula (II): In Formula (II), the value of p is an integer from 10 to 80, preferably an integer from 20 to 40; Q in the general formula of molecular expression OH The structural expression of the repeating unit is Formula (III): The structural expression of the Q segment in the molecular expression general formula is Formula (IV):

2. The modified MQ resin according to claim 1, characterized in that, In the molecular expression general formula, x = 0.05 - 0.17, y = 0.03 - 0.12; z = 0.67 - 0.

87.

3. The preparation method of the modified MQ resin according to claim 1 or 2, characterized in that, It includes the following steps: (1) Synthesize methyl MQ resin. Preferably, the molecular weight Mw of the methyl MQ resin is 18000 - 19500, and the hydroxyl content is 2 - 4 wt%. (2) Dissolve the methyl MQ resin and the aromatic hydrocarbon solvent at a certain temperature, keep stirring, add a poor solvent and mix well, then let it stand for fractionation. Remove the macromolecular resin precipitated in the lower layer, and rotary evaporate the upper solution to obtain MQ resin powder with a low macromolecular content. (3) After fully dissolving the fractionated MQ resin and the aromatic hydrocarbon solvent, add hydroxyl silicone oil and an acid catalyst for the next reaction. After the reaction is completed, neutralize the acid with a neutralizing agent, and filter to obtain the modified MQ resin.

4. The preparation method according to claim 3, characterized in that, In step (2), the aromatic hydrocarbon solvent is selected from one or more of benzene, toluene, and xylene, preferably xylene; and / or The poor solvent is selected from one or more of acetonitrile, methanol, acetone, ethyl acetate, and n-butanol, preferably acetonitrile; Preferably, the mass ratio of the methyl MQ resin, the aromatic hydrocarbon solvent, and the poor solvent is 1:(0.4 - 2.5):(0.01 - 0.5), preferably 1:(0.4 - 1):(0.05 - 0.1).

5. The preparation method according to claim 3 or 4, characterized in that, In step (2), the temperature of the dissolution is 25 - 80 °C, preferably 40 - 70 °C, and the time is 0.5 - 2 h; and / or For the stirring, the stirring speed is 50 - 200 revolutions per minute, and the stirring time is 0.5 - 3 h; and / or For the standing fractionation, the temperature is 25 - 80 °C, and the standing fractionation time is 0.5 - 3 h, preferably 1 h.

6. The preparation method according to any one of claims 3 to 5, characterized in that, In step (2), for the rotary evaporation, the temperature is 80 - 120 °C, preferably 100 - 120 °C, the rotary evaporation pressure is 0 - 10 mbar, preferably 0 - 5 mbar, and the rotary evaporation speed is 40 - 60 rpm, preferably 60 rpm.

7. The preparation method according to any one of claims 3 to 6, characterized in that, In step (2), the mass proportion of macromolecules (Mw > 60,000) in the MQ resin powder is less than 3 wt%, preferably less than 2 wt%.

8. The preparation method according to any one of claims 3 to 7, characterized in that, In step (3), the aromatic hydrocarbon solvent is selected from one or more of benzene, toluene, and xylene, preferably xylene; and / or The hydroxyl silicone oil is an alcohol hydroxyl single-capped silicone oil; and / or The acid catalyst is selected from one or more of trifluoromethanesulfonic acid and trifluoroacetic acid, preferably trifluoromethanesulfonic acid; Preferably, the mass ratio of the fractionated MQ resin, the aromatic hydrocarbon solvent, the hydroxyl silicone oil, and the acid catalyst is 1:(0.6 - 1):(0.4 - 0.8):(0.01 - 0.05).

9. The preparation method according to any one of claims 3 to 8, characterized in that, In step (3), the reaction temperature of the reaction is 70 - 120 °C, and the reaction time is 2 - 5 h; and / or In step (3), the neutralizing agent is calcium carbonate or sodium bicarbonate; Preferably, the dosage of the neutralizing agent is 5 - 10 times the mass of the acid catalyst.

10. Use of the modified MQ resin according to claim 1 or 2 or the modified MQ resin prepared by the preparation method according to any one of claims 3 to 9 in a pressure-sensitive adhesive.

Images