WO2019178876A1

WO2019178876A1 - Pressure-sensitive organosilicon adhesive and preparation method thereof

Info

Publication number: WO2019178876A1
Application number: PCT/CN2018/080364
Authority: WO
Inventors: 李战雄; 孙弋; 纵亚坤
Original assignee: 南通纺织丝绸产业技术研究院; 苏州大学
Priority date: 2018-03-23
Filing date: 2018-03-23
Publication date: 2019-09-26

Abstract

The invention discloses a pressure-sensitive organosilicon adhesive and a preparation method thereof. Using fluorine-containing phenyl silicone resin and silicone rubber (107 silicone rubber) as raw material, the pressure-sensitive organosilicon adhesive is prepared by a polycondensation reaction. Since a certain quantity of a fluorine-containing phenyl group is introduced into the structure of the product, the obtained pressure-sensitive organosilicon adhesive has excellent high-temperature resistance and adhesive properties, and has the advantages of a simple preparation process, low equipment requirements, and suitability for mass production.

Description

Silicone pressure sensitive adhesive and preparation method thereof

Technical field

The invention relates to a high temperature resistant silicone pressure sensitive adhesive and a preparation method thereof, and belongs to the field of preparation of organic silicon materials and adhesives.

Background technique

The active ingredient of the silicone pressure-sensitive adhesive is a product of a polycondensation reaction of a silicone resin and a silicone rubber (also known as a 107 rubber), which is diluted to a certain solid content by adding an organic solvent, and a crosslinking agent and other additives are added to obtain a product. Among them, the main role of silicone rubber is to give the pressure-sensitive adhesive the necessary cohesion. The 107 glue commonly used in the synthesis of silicone pressure-sensitive adhesive has a number average molecular weight of 100,000 to 500,000, which is generally colorless and transparent at room temperature. Extremely viscous liquid or semi-solid; the silicone resin contains a polar silanol group in its molecular structure, providing wetting, initial tack and peel strength to the pressure sensitive adhesive.

The most widely used silicone resin for preparing pressure sensitive adhesives is methyl silicone resin (referred to as MQ resin), which has the advantages of low raw material cost and good process performance. However, silicone pressure-sensitive adhesives synthesized from methyl silicone resin have poor heat resistance, and such pressure-sensitive adhesives may fail when used for a long period of time at temperatures exceeding 300 ° C due to methyl silicon in the adhesive macromolecule. The organic groups such as the base are thermally decomposed to increase the degree of cross-linking of the adhesive. The use of phenyl silicone resin instead of methyl silicone resin has a slightly better heat resistance, but debonding and brittleness occur after long-term use under ultra-high temperature conditions higher than 300 °C.

technical problem

The invention aims at the current situation of insufficient high temperature resistance of the existing silicone pressure sensitive adhesive, and provides a fluorine-containing high temperature resistant silicone pressure sensitive adhesive, and a high temperature molecular pressure of the fluorine-containing phenyl silicone resin and the high molecular weight 107 to prepare a high temperature resistant pressure. The method of the sensitive adhesive, the disclosed silicone pressure-sensitive adhesive has the characteristics of high temperature resistance and even high temperature resistance.

Technical solution

In order to achieve the object of the invention described in the present invention, the technical solution adopted is as follows:

A silicone pressure sensitive adhesive whose chemical structural formula is as follows:

Wherein m = 1 to 20; n = 1 to 5; p = 1 to 8; x = 0 to 6; y = 1 to 10.

The preparation method of the above silicone pressure sensitive adhesive comprises the following steps:

(1) adding an activator solution to a mixture of a 107 gum solution and a catalyst, and then adding a fluorine-containing phenyl silicone resin solution, and refluxing to obtain a polycondensation product;

(2) mixing the polycondensation product with the curing agent and the organic solvent, and then heat-increasing and curing to obtain a silicone pressure-sensitive adhesive;

The chemical structural formula of the fluorine-containing phenyl silicone resin is:

.

In the above technical solution, the mass ratio of the activator, 107 peptizer, catalyst, and fluorophenyl silicone resin is (0.005-0.05): 1: (0.005-0.06): (1-10); the polycondensation product The mass ratio to the curing agent is (0.02 to 0.5): (0.02 to 0.3).

In the above technical solution, the solvent in the activator solution is an aromatic hydrocarbon solvent; the solvent in the 107 gum solution is an aromatic hydrocarbon solvent; the solvent in the fluorine-containing phenyl silicone resin solution is an aromatic hydrocarbon solvent; the organic solvent Is isopropanol; the curing agent is hexamethyldisilazane; the catalyst is dibutyltin dilaurate; the activator is dimethyldimethoxysilane or dimethyldiethoxysilane .

In the above technical solution, in step (1), the catalyst is added to the 107 gum solution at 80 ° C to 100 ° C; then, under the protection of nitrogen, the activator solution is added dropwise, and the reaction is kept for 1 to 6 hours after the completion of the dropwise addition; Adding a fluorophenyl silicone resin solution, and refluxing at 100 to 140 ° C for 2 to 60 hours to obtain a polycondensation product;

In the step (2), the temperature of the heat preservation and curing is 100 to 140 ° C, and the time is 1 to 6 hours.

In the above technical solution, the time for adding the activator solution is 0.5 to 3 hours.

In the above technical solution, the preparation method of the fluorine-containing phenyl silicone resin comprises the following steps:

(1) Dissolving pentafluorostyrene in an aromatic hydrocarbon solvent, adding a noble metal salt catalyst under nitrogen protection; then adding methyldichlorosilane dropwise at 50 to 140 ° C; after the completion of the dropwise addition, the reaction is kept for 1 to 10 hours. Preparation of pentafluorophenethyldimethylchlorosilane;

(2) Dispersing water and inorganic acid in an organic solvent, and then adding a mixture of pentafluorophenethyldimethylchlorosilane and tetraethyl orthosilicate at 60-80 ° C, and then performing heat reduction for a polycondensation after completion of the dropwise addition. 0.5 to 1 hour; then, a mixture of trihydrocarbylmonochlorosilane and tetraethyl orthosilicate is added dropwise, and after completion of the dropwise addition, the polycondensation reaction is further carried out for 1 to 6 hours to prepare a fluorine-containing phenyl silicone resin.

In the above technical solution, the mass ratio of pentafluorostyrene, noble metal salt and methyldichlorosilane is 1: (0.003 to 0.006): (0.5 to 2); pentafluorophenethyldimethylchlorosilane and orthosilicate In the mixture of ethyl esters, the mass ratio of pentafluorophenethyldimethylchlorosilane to ethyl orthosilicate is (1 to 6): (1 to 10); trihydrocarbyl monochlorosilane and ethyl orthosilicate In the mixture, the mass ratio of trihydrocarbyl monochlorosilane to ethyl orthosilicate is (1 to 3): (1 to 10); the noble metal salt is chloroplatinic acid; and the trihydrocarbyl monochlorosilane is trimethyl One of chlorosilane, dimethylhydrogen monochlorosilane, dimethylvinylmonochlorosilane, phenyldimethylchlorosilane; the inorganic acid is concentrated sulfuric acid or concentrated hydrochloric acid.

In the above technical solution, the time of adding methyldichlorosilane is 0.5 to 5 hours; the time of adding the mixture of trihydrocarbylmonochlorosilane and ethyl orthosilicate is 0.5 to 1 hour; after the reaction of the step (1) is finished The reaction liquid is distilled off and distilled under reduced pressure to obtain pentafluorophenethyldimethylchlorosilane; after the step (2) is again subjected to polycondensation, the reaction liquid is subjected to cooling, vacuum distillation, liquid separation treatment, extraction, and distilled water washing. Drying, filtration, and distillation give a fluorine-containing phenyl silicone resin.

The invention also discloses the application of the fluorine-containing phenyl silicone resin in preparing the silicone pressure sensitive adhesive; the chemical structural formula of the fluorine-containing phenyl silicone resin is:

The chemical structural formula of the silicone pressure sensitive adhesive is as follows:

Wherein m = 1 to 20; n = 1 to 5; p = 1 to 8; x = 0 to 6; y = 1 to 10.

The aromatic hydrocarbon solvent of the present invention is a mixed solvent in which either or both of toluene and xylene are mixed in an arbitrary ratio; preferably, the reflux water separation time is from 2 to 60 hours, preferably from 12 to 24 hours.

The reaction formula of the fluorophenyl silicone resin and the 107 rubber disclosed in the invention for synthesizing the silicone pressure sensitive adhesive by polycondensation reaction is as follows:

Wherein m = 1 to 20; n = 1 to 5; p = 1 to 8; x = 0 to 6; y = 1 to 10;

R = -CH ₃ or -CH ₂ CH ₃ .

The preparation process of the fluorophenyl silicone high temperature pressure sensitive adhesive comprises a polycondensation reaction and a post-treatment two-step reaction, which can be specifically as follows:

(1) Polycondensation reaction

One part of 107 gum is dissolved in 0.5-10 parts of aromatic hydrocarbon solvent by weight, stirred and heated to 80 ° C ~ 100 ° C, and added 0.005 ~ 0.06 parts of dibutyl tin dilaurate (DBTL). Under nitrogen protection, add 0.005~0.05 parts of the activator dissolved in 0.1~0.5 parts of aromatic hydrocarbon solvent, add 0.5~3 hours, and keep the reaction for 1~6 hours after the addition. Then, adding 1 to 10 parts of a solution of fluorophenyl silicone resin dissolved in 1 to 10 parts of an aromatic hydrocarbon solvent, raising the temperature to 100 to 140 ° C, and refluxing the water for 2 to 60 hours;

(2) ripening

0.02-0.5 parts of the curing agent hexamethyldisilazane and 0.02-0.3 parts of isopropanol are added to the above polycondensation product by weight, and the reaction is kept for 1 to 6 hours. After the completion of the aging, the reaction was stopped, and the reaction liquid was cooled to room temperature, and discharged to obtain a high temperature resistant pressure sensitive adhesive.

The preparation method of the fluorine-containing phenyl silicone resin of the present invention can be specifically as follows:

(1) Hydrosilylation reaction

1 part by weight of pentafluorostyrene is dissolved in 1 to 10 parts of aromatic hydrocarbon solvent, 0.003~0.006 parts of chloroplatinic acid catalyst is added under nitrogen protection, heated to 50~140 °C, and then added dropwise for a certain period of time. 0.5~2 parts of methyldichlorosilane, the reaction is continued for 1~10 hours after the addition. After the reaction is completed, the solvent and unreacted methyldichlorosilane are distilled off, and a 132 ° C fraction (3.75 kPa) is collected by distillation under reduced pressure to obtain pentafluorophenethyldimethylchlorosilane;

(2) shrink polymerization into silicone resin

Mixed silane: 1~3 parts of monochlorosilane monomer, 1~6 parts of pentafluorophenethyldimethylchlorosilane and 2~20 parts of ethyl orthosilicate are mixed by weight to obtain mixed silane;

Polycondensation reaction: 1 to 5 parts of water and 0.5 to 2 parts of inorganic acid are dispersed in 1 to 20 parts of tetrahydrofuran by weight, and the temperature of the mixture is raised to 60 to 80 ° C by heating, and the above mixed silane is slowly added dropwise. Add 0.5 to 2 hours. After the addition is completed, the insulation reaction is continued for 1 to 6 hours;

Post-treatment: After cooling the reaction liquid, the by-product ethanol and the solvent tetrahydrofuran were distilled off under reduced pressure, and the distillation temperature was 40 to 80 ° C, and the degree of vacuum was 0.5 to 20 mmHg. Pour the remaining reaction solution into the separatory funnel and extract it with extractant for 3 to 5 times, using 1 to 5 portions of extractant each time. The extracts were combined and washed 3 to 5 times with distilled water, using 1 to 5 portions of distilled water each time. Add 0.2~1 part of desiccant and dry for 0.5~5 hours. The desiccant was removed by filtration, and distilled to obtain a white loose solid product of fluorophenyl silicone resin, the distillation temperature was 40 to 80 ° C, and the degree of vacuum was 0.5 to 20 mmHg.

Beneficial effect

The outstanding advantages of the present invention over the prior art are:

1. Different from the traditional silicone pressure sensitive adhesive preparation, the silicone silicone resin, the vinyl silicone resin and the phenyl silicone resin are used. The invention uses the pentafluorophenyl modified silicone resin as a raw material to prepare the silicone pressure sensitive adhesive. Has very good heat resistance.

2. The high temperature resistant silicone pressure sensitive adhesive provided by the invention is activated by adding an activator during the preparation of the adhesive, which can overcome the problem of poor reactivity of the extremely rigid pentafluorophenyl group introduced into the silicone resin; The heat resistance of the adhesive is deteriorated, so that the adhesive is aged by adding hexamethyldisilazane before the end of the reaction.

3. The high temperature resistant silicone pressure sensitive adhesive provided by the invention has an easy ratio of fluorine-containing phenyl silicone resin and 107 rubber, and is convenient for preparing an adhesive suitable for different heat resistance requirements.

4. The raw materials used in the preparation of the fluorine-containing phenyl silicone pressure-sensitive adhesive of the invention are easy to obtain, the synthesis process is simple, and it is suitable for industrial production.

DRAWINGS

Figure 1 is a graph showing the thermal weight loss of the pressure sensitive adhesive of the present invention.

Embodiments of the invention

The technical solutions of the present invention are further described below in conjunction with the accompanying drawings and embodiments.

The performance detection steps of the present invention are as follows:

Add 1~3 parts of diluent, 0.02~0.05 parts of fluorophenyl silicone pressure sensitive adhesive and 0.0005~0.002 parts of cross-linking agent in the container by weight, stir and dissolve evenly, and the obtained diluted glue is gathered. The ester film is coated with a glue coating machine to control the thickness of the adhesive layer to be 0.05 to 0.06 mm. After coating, dry at 70~100 °C for 1~5 minutes, then dry at 110~160 °C for 1~15 minutes.

The bonding strength and heat aging resistance were tested according to GB/T 2792-1998 (pressure-sensitive adhesive 180° peel strength test method) and GB/T 17875-1999 (pressure-sensitive adhesive accelerated aging test method).

The invention uses a pentafluorophenyl silicone resin and a high molecular weight 107 glue as raw materials to synthesize a fluorine-containing phenyl silicone pressure sensitive adhesive by polycondensation reaction, and the product introduces a pentafluorophenyl modified silicone resin, which has a total of pentafluorophenyl groups. The planar structure of the yoke and the fluorocarbon bond which is difficult to thermally debond the bond, the product has very excellent heat resistance.

The crosslinking agent used in the performance testing process is any one of dibenzoyl peroxide or peroxy-2,4-dichlorobenzoyl.

Embodiment 1

(1) Synthesis of fluorine-containing phenyl silicone resin

A 5 L three-necked flask equipped with a thermometer, a reflux condenser, and a constant pressure dropping funnel, heated in an oil bath. 800 g of toluene and 650 g of pentafluorostyrene were successively added, stirred and dissolved, and 2.6 g of a chloroplatinic acid catalyst was added under a nitrogen atmosphere. The heating was turned on, and after heating to 80 ° C, 510 g of methyldichlorohydrosilane was added dropwise, and the addition was completed in 30 minutes, and the dropping time was controlled to about 1 hour. After the completion of the dropwise addition, the reaction was kept for 2 hours. After completion of the reaction, the solvent and unreacted methyldichlorosilane were distilled off, and a 132 ° C fraction (3.75 kPa) was collected under reduced pressure to obtain 950 g of pentafluorophenethyldimethylchlorosilane, and the purity of the product was determined by gas chromatography to be 96.6. %, yield 90.9%.

80 g of trimethylchlorosilane, 194 g of pentafluorophenethyldimethylchlorosilane and 630 g of tetraethyl orthosilicate were uniformly mixed in a 250 mL Erlenmeyer flask to obtain a mixed silane, which was used.

A 500 mL three-necked flask equipped with a thermometer, a reflux condenser, and a constant pressure dropping funnel, heated in an oil bath. First, 80 g of water and 50 g of concentrated sulfuric acid were carefully and slowly introduced into 500 g of tetrahydrofuran, and after heating to raise the temperature of the mixture to 70 ° C, the above-prepared mixed silane was slowly added dropwise, and the dropping time was controlled at about 45 minutes. After the addition was completed, the reaction was continued for 6 hours. The reaction was stopped, and the reaction liquid was first distilled under reduced pressure to remove by-product ethanol and solvent tetrahydrofuran. The distillation temperature was 60 ° C, the degree of vacuum was 10 mmHg, and distillation was carried out until no liquid was distilled off. The toluene was extracted three times, and the amount of toluene used each time was 300 g. The extracts were combined and washed 5 times with distilled water using 150 g of distilled water each time. After the end of the washing, it was further dried by adding 60 g of anhydrous sodium sulfate for 5 hours. The desiccant was removed by filtration, and distilled under the conditions of a temperature of 80 ° C and a vacuum of 0.5 mmHg to obtain 380 g of a white loose solid product fluorophenyl silicone resin.

(2) polycondensation reaction

2L three-necked flask equipped with thermometer, water separator and reflux condenser, constant pressure addition funnel, heated in oil bath. 180 g of 107 gum and 160 g of toluene were successively added, and the mixture was heated to 80 ° C with stirring, and 1.7 g of dibutyltin dilaurate (DBTL) was added. A solution of 1.2 g of dimethyldiethoxysilane dissolved in 20 g of toluene was added dropwise with nitrogen gas, and the addition was completed for 30 minutes, and the reaction was kept for 3 hours. Then, a solution of 220 g of a fluorine-containing phenyl silicone resin dissolved in 210 g of toluene was added, the temperature was raised to 110 ° C, and the reaction was refluxed for 24 hours.

(3) Post processing

The polycondensation product was added with 12 g of hexamethyldisilazane and 4.6 g of isopropanol, and the mixture was aged for 5 hours. After the reaction is completed, the reaction is stopped, cooled, and discharged to obtain a high temperature resistant pressure sensitive adhesive. During the ripening process, a small amount of uncondensed silanol groups are further reacted.

(4) Gluing process

200 g of toluene, 4 g of fluorophenyl silicone pressure sensitive adhesive and 0.1 g of dibenzoyl peroxide (BPO) were sequentially added to the vessel, and after stirring uniformly, the obtained diluted gum was coated on the polyester film by a gluing machine. Glue, control the thickness of the adhesive layer is 0.05~0.06mm. After coating, it was dried at 90 ° C for 2 min and then dried at 150 ° C for 5 min.

(5) Bonding test

According to GB/T 2792-1998: Pressure Sensitive Adhesive 180° Peel Strength Test Method, the peel strength of the fluorine-containing phenyl silicone pressure sensitive adhesive was measured to be 40.5 N (2.5 cm). According to GB/T 17875-1999: Pressure-sensitive adhesive accelerated aging test method, the adhesive was tested to resist compression and oxidation at 325 ° C for 72 h, and can be smoothly removed from the metal surface after exposure at 260 ° C. The molecular structure of the above silicone pressure sensitive adhesive product is as follows:

Where m = 2 to 10; n = 1 to 3; p = 1 to 3; x = 1 to 5; y = 2 to 6.

Embodiment 2

(1) The procedure for synthesizing the fluorine-containing phenyl silicone resin is the same as in the first embodiment.

(2) polycondensation reaction

2L three-necked flask equipped with thermometer, water separator and reflux condenser, constant pressure addition funnel, heated in oil bath. 170 g of 107 gum and 165 g of xylene were successively added, and the mixture was heated to 90 ° C with stirring, and 1.5 g of dibutyltin dilaurate (DBTL) was added. A solution of 1 g of dimethyldimethoxysilane dissolved in 20 g of xylene was added dropwise with nitrogen, and the reaction was completed in 30 min, and the reaction was kept for 3 h. Then, a solution of 325 g of a fluorine-containing phenyl silicone resin dissolved in 200 g of xylene was added, the temperature was raised to 138 ° C, and the reaction was refluxed for 24 hours.

(3) Post processing

The polycondensation product was added with 15 g of hexamethyldisilazane and 6.5 g of isopropanol, and the reaction was kept for 5 hours. After the reaction is completed, the reaction is stopped, cooled, and discharged to obtain a high temperature resistant pressure sensitive adhesive.

(4) Gluing process

200 g of xylene, 4 g of fluorophenyl silicone pressure sensitive adhesive and 0.1 g of peroxy-2,4-dichlorobenzoyl were sequentially added to the vessel, and after stirring uniformly, the obtained diluted gum was applied on the polyester film. The glue coating machine is glued to control the thickness of the adhesive layer to be 0.05~0.06mm. After coating, it was dried at 100 ° C for 2 min and then dried at 130 ° C for 5 min.

(5) Bonding test

According to GB/T 2792-1998: Pressure Sensitive Adhesive 180° Peel Strength Test Method, the peel strength of the fluorine-containing phenyl silicone pressure sensitive adhesive was measured to be 31.5 N (2.5 cm). According to GB/T 17875-1999: Pressure-sensitive adhesive accelerated aging test method, the adhesive was tested to resist compression and oxidation at 325 ° C for 72 h, and can be smoothly removed from the metal surface after exposure at 260 ° C.

The molecular structure of the above pressure sensitive adhesive product is as follows:

Where m = 2 ~ 8; n = 1 ~ 3; p = 1 ~ 3; x = 2 ~ 5; y = 3 ~ 8.

Embodiment 3

(1) Polycondensation reaction

2L three-necked flask equipped with thermometer, water separator and reflux condenser, constant pressure addition funnel, heated in oil bath. 169 g of 107 gum and 180 g of xylene were successively added, and the mixture was heated to 80 ° C with stirring, and 1.5 g of dibutyltin dilaurate (DBTL) was added. A solution of 1 g of dimethyldimethoxysilane dissolved in 20 g of xylene was added dropwise with nitrogen, and the reaction was completed in 30 min, and the reaction was kept for 3 h. Then, a solution of 320 g of a fluorine-containing phenyl silicone resin dissolved in 200 g of xylene was added, the temperature was raised to 140 ° C, and the reaction was refluxed for 48 hours.

(2) Post processing

(3) Gluing process

200 g of toluene, 4 g of fluorophenyl silicone pressure sensitive adhesive and 0.1 g of diphenylformyl peroxide (BPO) were sequentially added to the vessel, and after stirring uniformly, the obtained diluted gum was applied to the polyester film by a gluing machine. Gluing, control the thickness of the adhesive layer is 0.05~0.06mm. After coating, it was dried at 100 ° C for 2 min and then dried at 150 ° C for 5 min.

(4) Bonding test

According to GB/T 2792-1998: 180 ° peel strength test method of pressure sensitive adhesive, the peeling strength of the fluorine-containing phenyl silicone pressure sensitive adhesive was measured to be 30.3 N (2.5 cm). According to GB/T 17875-1999: Pressure-sensitive adhesive accelerated aging test method, the adhesive was tested to resist compression and oxidation at 325 ° C for 72 h, and can be smoothly removed from the metal surface after exposure at 260 ° C. The molecular structure of the above pressure sensitive adhesive product is as follows:

Where m = 2 to 10; n = 2 to 4; p = 2 to 4; x = 2 to 5; y = 3 to 7.

Embodiment 4

(1) Polycondensation reaction

2L three-necked flask equipped with thermometer, water separator and reflux condenser, constant pressure addition funnel, heated in oil bath. 140 g of 107 gum and 150 g of toluene were successively added, and the mixture was heated to 80 ° C with stirring, and 1.5 g of dibutyltin dilaurate (DBTL) was added. A solution of 1 g of dimethyldiethoxysilane dissolved in 18 g of toluene was added dropwise with nitrogen, and the mixture was added for 30 minutes, and the reaction was kept for 3 hours. Then, a solution of 325 g of a fluorine-containing phenyl silicone resin dissolved in 200 g of toluene was added, the temperature was raised to 110 ° C, and the reaction was refluxed for 20 hours.

(2) Post processing

(3) Gluing process

(4) Bonding test

According to GB/T 2792-1998: 180 ° peel strength test method of pressure sensitive adhesive, the peeling strength of the fluorine-containing phenyl silicone pressure sensitive adhesive was 29.8 N (2.5 cm). According to GB/T 17875-1999: Pressure-sensitive adhesive accelerated aging test method, the adhesive was tested to resist compression and oxidation at 325 ° C for 72 h, and can be smoothly removed from the metal surface after exposure at 260 ° C.

The molecular structure of the above fluorophenyl silicone pressure sensitive adhesive product is as follows:

Where m = 2 to 9; n = 2 to 4; p = 2 to 5; x = 2 to 5; y = 4 to 10.

Figure 1 is a graph of the above-mentioned pressure-sensitive adhesive thermal weight loss curve. In the figure, curve a is the thermogravimetric test result of the thermogravimetric test of the pressure sensitive adhesive prepared in the first embodiment, b is the thermogravimetric test result of the thermosensitive weight test of the pressure sensitive adhesive prepared in the second embodiment, and c is the pressure prepared in the third embodiment. The thermogravimetric test results of the thermosensitive rubber have a thermogravimetric curve, and d is a thermogravimetric curve of the thermogravimetric test results of the pressure-sensitive adhesive prepared in Example 4. It can be seen that all pressure sensitive adhesives have good heat resistance. It can also be seen from the heat resistance test results that the pressure sensitive adhesive prepared by the present invention has good heat resistance, and the 10% weight loss temperature reaches 342 °C.

Comparative Example 1: phenethyl silicone pressure sensitive adhesive

(1) Synthesis of phenethyl silicone resin

A 500 mL three-necked flask equipped with a thermometer, a reflux condenser, and a constant pressure dropping funnel, heated in an oil bath. 80 g of toluene and 33 g of styrene were successively added, stirred and dissolved, and 0.16 g of a chloroplatinic acid catalyst was added under a nitrogen atmosphere. The heating was turned on, and after heating to 80 ° C, 50 g of methyldichlorohydrosilane was added dropwise, and the dropping time was controlled to about 1 hour. After the completion of the dropwise addition, the reaction was kept for 2 hours. After the completion of the reaction, the solvent and the unreacted methyldichlorosilane were distilled off, and a 112 ° C fraction (3.75 kPa) was collected by distillation under reduced pressure to obtain 76 g of benzene ethyl dimethyl chlorosilane as a colorless transparent liquid product. The purity was 95.3%, and the yield was 91.6%.

9 g of trimethylmonochlorosilane, 16 g of phenethyldimethylchlorosilane and 63 g of tetraethyl orthosilicate were uniformly mixed in a 250 mL Erlenmeyer flask to obtain a mixed silane, which was used.

A 500 mL three-necked flask equipped with a thermometer, a reflux condenser, and a constant pressure dropping funnel, heated in an oil bath. First, 7 g of water and 6 g of concentrated sulfuric acid were carefully and slowly introduced into 55 g of tetrahydrofuran, and after heating to raise the temperature of the mixture to 72 ° C, the above-prepared mixed silane was slowly added dropwise, and the dropping time was controlled for 30 to 50 minutes. After the addition was completed, the reaction was continued for 6 hours. The reaction was stopped, and the reaction liquid was first distilled under reduced pressure to remove by-product ethanol and solvent tetrahydrofuran. The distillation temperature was 60 ° C, the degree of vacuum was 10 mmHg, and distillation was carried out until no liquid was distilled off. The toluene was extracted three times, and the amount of toluene used each time was 30 g. The extracts were combined and washed 5 times with distilled water, using 15 g of distilled water each time. After the end of the washing, it was further dried by adding 5 g of anhydrous sodium sulfate for 6 hours. The desiccant was removed by filtration, and distilled under the conditions of a temperature of 80 ° C and a vacuum of 0.5 mmHg to obtain 36 g of a white loose solid product phenethyl silicone resin.

(2) polycondensation reaction

A 250 mL three-necked flask equipped with a thermometer, a water separator and a reflux condenser, a constant pressure addition funnel, and an oil bath. 107 g of 16.8 g and 16 g of toluene were successively added, and the mixture was heated to 80 ° C with stirring, and 0.18 g of dibutyltin dilaurate (DBTL) was added. A solution of 0.13 g of dimethyldiethoxysilane dissolved in 2.5 g of toluene was added dropwise with nitrogen gas, and the mixture was added in 30 minutes, and the reaction was kept for 3 hours. Then, a solution of 22 g of phenethyl silicone resin dissolved in 25 g of toluene was added, the temperature was raised to 110 ° C, and the reaction was refluxed for 24 hours.

(3) Post processing

The polycondensation product was added with 0.12 g of hexamethyldisilazane and 0.46 g of isopropyl alcohol, and the reaction was kept for 5 hours. After the reaction was over, the reaction was stopped, cooled, and discharged to obtain a control sample silicone pressure-sensitive adhesive.

(4) Gluing process

200 g of toluene, 4 g of phenethyl silicone pressure sensitive adhesive and 0.1 g of dibenzoyl peroxide (BPO) were sequentially added to the vessel, and after stirring uniformly, the obtained diluted gum was applied to the polyester film by a glue coating machine. The thickness of the control glue layer is 0.05~0.06mm. After coating, it was dried at 90 ° C for 2 min and then dried at 150 ° C for 5 min.

(5) Bonding test

According to GB/T 2792-1998: 180 ° peel strength test method of pressure sensitive adhesive, the peel strength of phenyl silicone pressure sensitive adhesive was measured to be 30.8 N (2.5 cm). According to GB/T 17875-1999: accelerated aging test method of pressure sensitive adhesive, the adhesive is resistant to compression and oxidation at 325 ° C for 72 h, 80% of the adhesive layer is peeled off after exposure at 260 ° C, and some adhesive layer remains on the metal surface, residual The glue layer becomes brittle, the color is white, the side is shrinking, and the pores appear. The molecular structure of the control silicone pressure sensitive adhesive product is as follows:

Where m = 2 to 12; n = 2 to 3; p = 2 to 4; x = 2 to 5; y = 3 to 7.

Claims

A silicone pressure sensitive adhesive characterized in that the chemical structural formula of the silicone pressure sensitive adhesive is as follows:

Wherein m = 1 to 20; n = 1 to 5; p = 1 to 8; x = 0 to 6; y = 1 to 10.
The method for preparing a silicone pressure sensitive adhesive according to claim 1, comprising the steps of:

(1) adding an activator solution to a mixture of a 107 gum solution and a catalyst, and then adding a fluorine-containing phenyl silicone resin solution, and refluxing to obtain a polycondensation product;

(2) mixing the polycondensation product with the curing agent and the organic solvent, and then heat-increasing and curing to obtain a silicone pressure-sensitive adhesive;

The chemical structural formula of the fluorine-containing phenyl silicone resin is:

.
The method for preparing a silicone pressure-sensitive adhesive according to claim 2, wherein the mass ratio of the activator, 107 peptizer, catalyst, and fluorine-containing phenyl silicone resin is (0.005 to 0.05): 1: (0.005) ～0.06): (1 to 10); the mass ratio of the polycondensation product to the ripening agent is (0.02 to 0.5): (0.02 to 0.3).
The method for preparing a silicone pressure-sensitive adhesive according to claim 2, wherein the solvent in the activator solution is an aromatic hydrocarbon solvent; the solvent in the 107 gum solution is an aromatic hydrocarbon solvent; and the fluorine-containing phenyl silicon The solvent in the resin solution is an aromatic hydrocarbon solvent; the organic solvent is isopropyl alcohol; the curing agent is hexamethyldisilazane; the catalyst is dibutyltin dilaurate; the activator is dimethyl Dimethoxysilane or dimethyldiethoxysilane.
The method for preparing a silicone pressure-sensitive adhesive according to claim 2, wherein

In the step (1), the catalyst is added to the 107 gum solution at 80 ° C to 100 ° C; then the activator solution is added dropwise under nitrogen protection, and the reaction is kept for 1 to 6 hours after the completion of the dropwise addition; then the fluorine-containing phenyl group is added. The silicone resin solution is refluxed at 100 to 140 ° C for 2 to 60 hours to obtain a polycondensation product;

In the step (2), the temperature of the heat preservation and curing is 100 to 140 ° C, and the time is 1 to 6 hours.
The method for preparing a silicone pressure-sensitive adhesive according to claim 5, wherein the time for adding the activator solution is 0.5 to 3 hours.
The method for preparing a silicone pressure-sensitive adhesive according to claim 2, wherein the method for preparing the fluorine-containing phenyl silicone resin comprises the following steps:

(1) Dissolving pentafluorostyrene in an aromatic hydrocarbon solvent, adding a noble metal salt catalyst under nitrogen protection; then adding methyldichlorosilane dropwise at 50 to 140 ° C; after the completion of the dropwise addition, the reaction is kept for 1 to 10 hours. Preparation of pentafluorophenethyldimethylchlorosilane;

(2) Dispersing water and inorganic acid in an organic solvent, and then adding a mixture of pentafluorophenethyldimethylchlorosilane and tetraethyl orthosilicate at 60-80 ° C, and then performing heat reduction for a polycondensation after completion of the dropwise addition. 0.5 to 1 hour; then, a mixture of trihydrocarbylmonochlorosilane and tetraethyl orthosilicate is added dropwise, and after completion of the dropwise addition, the polycondensation reaction is further carried out for 1 to 6 hours to prepare a fluorine-containing phenyl silicone resin.
The method for preparing a silicone pressure-sensitive adhesive according to claim 7, wherein the mass ratio of pentafluorostyrene, noble metal salt and methyldichlorosilane is 1: (0.003 to 0.006): (0.5 to 2); In a mixture of pentafluorophenethyldimethylchlorosilane and ethyl orthosilicate, the mass ratio of pentafluorophenethyldimethylchlorosilane to tetraethyl orthosilicate is (1 to 6): (1 to 10) a mixture of trihydrocarbyl monochlorosilane and tetraethyl orthosilicate, the mass ratio of trihydrocarbyl monochlorosilane to ethyl orthosilicate is (1 to 3): (1 to 10); the noble metal salt is chlorine a platinum acid; the trihydrocarbyl monochlorosilane is one of trimethylchlorosilane, dimethylhydrogen monochlorosilane, dimethylvinylmonochlorosilane, phenyldimethylchlorosilane; The inorganic acid is concentrated sulfuric acid or concentrated hydrochloric acid.
The method for preparing a silicone pressure-sensitive adhesive according to claim 7, wherein the methyldichlorosilane is added dropwise for 0.5 to 5 hours; and a mixture of trihydrocarbylmonochlorosilane and tetraethyl orthosilicate is added dropwise. The time is 0.5~1 hour; after the end of the step (1), the reaction liquid is distilled off and distilled under reduced pressure to obtain pentafluorophenethyldimethylchlorosilane; after the step (2) is completed again, the reaction liquid is cooled. , vacuum distillation, liquid separation treatment, extraction, distilled water washing, drying, filtration, and distillation to obtain a fluorine-containing phenyl silicone resin.
The use of a fluorine-containing phenyl silicone resin in the preparation of a silicone pressure sensitive adhesive; the chemical structural formula of the fluorine-containing phenyl silicone resin is:

The chemical structural formula of the silicone pressure sensitive adhesive is as follows:

Wherein m = 1 to 20; n = 1 to 5; p = 1 to 8; x = 0 to 6; y = 1 to 10.