Compression set control agent as well as preparation method and application thereof

Abstract

The invention discloses a permanent compression set control agent and a preparation method and application thereof, the permanent compression set control agent has a molecular structure shown as the following: # imgabs0 #, and R1 and R2 are respectively selected from one of C1-C3 alkyl groups. The compression set control agent provided by the invention is of a short-chain structure, small in weight-average molecular weight and low in viscosity, molecules contain benzene rings, amino groups, vinyl groups and alkoxy structures, after fumed silica is modified by the compression set control agent, the amino groups are more easily attached to the surface of the fumed silica due to strong polarity, and the fumed silica is more stable in performance. The organosilicone sealant material is prepared from the compression set control agent and the modified fumed silica, the compression set performance of the organosilicone sealant can be obviously improved, the compression set of the organosilicone sealant is low, the tensile strength reaches up to 6.0 MPa or above, the phenomena of filler sedimentation, hardening and the like do not occur in the storage period, and the organosilicone sealant material has a good application prospect. And the stability and the reliability in the long-term use process are obviously improved.

Description

Technical Field

[0001] The invention belongs to the technical field of organic silicon materials, and in particular relates to a compression permanent deformation controller and a preparation method and application thereof. Background Art

[0002] In recent years, new energy vehicles have been widely popularized and applied. Their key components include three major systems: motor, electronic control, and battery. Among them, the electronic control system is responsible for the energy distribution and power control of new energy vehicles. In order to ensure that the components and electronic equipment inside the electronic control system are not damaged by environmental factors during long-term use, very high requirements are placed on the sealing of the electronic control system. If the sealing is poor, the inside of the electronic control system will be corroded by dust, moisture, mold, etc., which may cause damage to the electronic control system, short circuit, and even cause accidents during the driving of the car.

[0003] Since silicone sealants have good waterproofness, dustproofness, heat resistance, weather resistance, plasticity, adhesion, and can fully fit the surface of the shell to ensure the sealing effect, they are widely used in the electronic control system of new energy vehicles. At present, the common silicone sealants on the market have defects such as low extrusion rate, large permanent compression deformation, and colloid residue on the shell after aging. In particular, the permanent compression deformation of the sealing material is related to the stability and reliability of the electronic control system for long-term use. The Chinese invention patent, publication number CN112852167A, discloses a low-hardness transparent liquid silicone rubber composition with low compression deformation. The compression deformation performance is improved by adding side vinyl silicone oil and vinyl MQ silicone resin, but it is a two-component A and B component, which needs to be mixed before use. It is troublesome to use and has been gradually eliminated by the market. The Chinese invention patent, publication number CN115386333, discloses a low compression set single-component heat-curing silicone sealant, which improves strength and reduces compression set by adding vinyl MQ silicone resin containing benzene rings or epoxy. However, after the phenyl unit is introduced, the viscosity of the sealant increases significantly, the sizing property is seriously lost, and it cannot meet more stringent requirements. Summary of the invention

[0004] In order to solve the technical problems existing in the prior art, the purpose of the present invention is to provide a compression set controller and a preparation method and application thereof. The low compression set organic silicone sealant is made by using the compression set controller, which can significantly improve the compression set performance of the organic silicone sealant and enhance its stability and reliability during long-term use.

[0005] In order to achieve the above purpose and the above technical effect, the technical solution adopted by the present invention is:

[0006] The present invention discloses a compression set controller, wherein the compression set controller has a molecular structure as shown below:

[0007]

[0008] Wherein, R1 and R2 are each selected from one of C1-C3 alkyl groups.

[0009] Furthermore, the compression set controller has a weight average molecular weight of 300-500, a viscosity of 100-1000 cps, and a vinyl content of 20%-30%.

[0010] The present invention also discloses a method for preparing a compression set controlling agent, comprising the following steps:

[0011] Step 1: In a protective atmosphere, using γ-chloropropyltrialkoxysilane and p-phenylenediamine as raw materials, under the action of a first catalyst, a Cl substitution reaction is performed to prepare an intermediate product containing a benzene ring and an amino structure. The reaction equation is:

[0012]

[0013] Step 2: Using the intermediate product and vinyltrimethoxysilane as raw materials, under the action of the second catalyst, a condensation reaction is performed to prepare the desired compression set control agent. The reaction equation is:

[0014]

[0015] Furthermore, in step one, the molar ratio of γ-chloropropyltrialkoxysilane to p-phenylenediamine is 1:0.8-1.5; the temperature of the Cl substitution reaction is 80-120°C, and the time is 1-5h; the first catalyst is at least one of an organic tin catalyst, a titanate catalyst, and an acid catalyst, and the acid catalyst is dilute hydrochloric acid and / or dilute sulfuric acid.

[0016] Furthermore, in step 2, the molar ratio of the intermediate product to vinyltrimethoxysilane is 1:0.8-2; the temperature of the condensation reaction is 60-80°C, and the time is 2-6h; and the second catalyst is at least one of a Lewis acid and a Lewis base.

[0017] The invention also discloses the application of a compression permanent deformation controller in the preparation of surface modified gas silicon.

[0018] The present invention also discloses a method for preparing surface-modified gas silicon, comprising the following steps:

[0019] The compression set controller is dissolved in a solvent, heated to 50-70°C, preheated for 20-40 minutes, and then fumed silica is added, heated to 70-90°C, reacted for 100-150 minutes, cooled, and dried to obtain the desired surface-modified fumed silica.

[0020] Furthermore, after adding the fumed silica, stirring is performed at a stirring rate of 50-100 r / min, a drying temperature of 110-130° C., and a drying time of 50-70 min.

[0021] The invention also discloses the use of a compression permanent deformation controller in the preparation of a low compression permanent deformation organic silicon sealant.

[0022] The present invention also discloses a low compression permanent deformation organic silicon sealant, which comprises the following components in parts by weight:

[0023] 100 parts of vinyl silicone oil

[0024] Vinyl silicone resin 10-30 parts

[0025] 5-15 parts of hydrogen silicone oil

[0026] Surface modified gas silicon 20-50 parts

[0027] Flame retardant filler 20-35 parts

[0028] 1-3 parts of tackifier

[0029] Compression set control agent 1-3 parts

[0030] Catalyst 0.05-0.15 parts

[0031] Inhibitor 0.1-0.5 parts

[0032] 1-5 parts of phenylmethyl silicone oil.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The invention discloses a compression set controller and a preparation method and application thereof. The compression set controller has a short chain structure, a small weight average molecular weight, and low viscosity. The molecule contains a benzene ring, an amino group, a vinyl group, and an alkoxy group structure. After the fumed silica is modified by the compression set controller, the amino group has strong polarity and is more easily attached to the surface of the fumed silica. The compression set controller and the modified fumed silica are used to synergistically prepare an organic silicon sealant material, which can significantly improve the compression set performance of the organic silicon sealant. The organic silicon sealant has low compression set, a tensile strength of up to 6.0 MPa or more, no filler sedimentation, caking, and the like occur during the storage period, the storage stability is good, the aging stability is excellent, the stability and reliability of the organic silicon sealant in the long-term use process are significantly improved, and the probability of safety accidents occurring in a motor system is reduced. The reaction raw materials are easily available, the preparation is simple, the reaction process is stable, and industrial production is easily realized. DETAILED DESCRIPTION

[0035] The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0036] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0037] On the one hand, the present invention discloses a compression set controller having a weight average molecular weight of 300-500, preferably 370-450, a vinyl content of 20%-30%, and a viscosity of 100-1000cps, preferably 350-750cps, and more preferably 500-700cps. The compression set controller provided by the present invention has a molecular structure as shown below:

[0038]

[0039] Wherein, R1 and R2 are each selected from one of C1-C3 alkyl groups.

[0040] On the other hand, the present invention also discloses a method for preparing a compression set controlling agent, comprising the following steps:

[0041] Step 1: In a protective atmosphere, using γ-chloropropyltrialkoxysilane (γ-chloropropyltrimethoxysilane or γ-chloropropyltriethoxysilane) and p-phenylenediamine as raw materials, under the action of a first catalyst, a Cl substitution reaction is performed to prepare an intermediate product containing a benzene ring and an amino structure, and the reaction equation is:

[0042]

[0043] Step 2: Using the intermediate product and vinyltrimethoxysilane as raw materials, under the action of the second catalyst, a condensation reaction is performed to prepare the desired compression set control agent. The reaction equation is:

[0044]

[0045] In step 1, the protective atmosphere is nitrogen, and the molar ratio of γ-chloropropyltrialkoxysilane to p-phenylenediamine is 1:0.8-1.5, preferably 1:1-1.5.

[0046] In step 1, the temperature of the Cl substitution reaction is 80-120° C. and the time is 1-5 h.

[0047] In step 1, the first catalyst is at least one of an organic tin catalyst, a titanate catalyst, and an acid catalyst, wherein the acid catalyst is dilute hydrochloric acid and / or dilute sulfuric acid.

[0048] In step 1, γ-chloropropyltrialkoxysilane, p-phenylenediamine, a first catalyst and a solvent are first mixed, and then a Cl substitution reaction is carried out to obtain the desired intermediate product.

[0049] In step 2, the molar ratio of the intermediate product to vinyltrimethoxysilane is 1:0.8-2.

[0050] In step 2, the condensation reaction temperature is 60-80°C and the time is 2-6h.

[0051] In step 2, the second catalyst is at least one of a Lewis acid and a Lewis base.

[0052] In step 2, the intermediate product, the second catalyst and the solvent are first mixed, and then vinyltrimethoxysilane is gradually added dropwise to prepare the desired compression set control agent through a condensation reaction.

[0053] The solvent is at least one of toluene, xylene, methyl ethyl ketone and ethyl acetate.

[0054] The compression set controller provided by the present invention has a short-chain structure, a small weight-average molecular weight, and a low viscosity. The molecule contains a benzene ring, an amino group, a vinyl group, and an alkoxy structure. The amino group has a strong polarity, and the vinyl group is more easily exposed in the short-chain structure, thereby improving its reactivity. The compression set controller can undergo a cross-linking reaction with hydrogen-containing silicone oil, and is more likely to form a tighter triple network structure. The organic silicone sealant prepared by the compression set controller can significantly improve the compression set performance of the organic silicone sealant, and enhance its stability and reliability during long-term use.

[0055] The invention also discloses the application of a compression permanent deformation controller in the preparation of surface modified gas silicon.

[0056] A surface modified gas silica, wherein the specific surface area of ​​the compression permanent deformation control agent is 100-400m 2 / g (preferably 200-400m 2 / g) of fumed silica is surface modified, and vinyl groups can be introduced on the surface of the fumed silica. The specific steps include:

[0057] Dissolve 1-3 parts of compression set controller in 100 parts of solvent, heat to 50-70°C, preheat for 20-40 minutes, then add 20-50 parts of fumed silica, stir at a stirring rate of 50-100r / min, heat to 70-90°C, react for 100-150 minutes, cool, dry at a drying temperature of 110-130°C and a drying time of 50-70 minutes to obtain the desired surface-modified fumed silica. The reaction equation is:

[0058]

[0059] Among them, R3 is

[0060] The present invention adopts a compression permanent deformation controller as a modifier to modify the fumed silica. The obtained surface-modified fumed silica has high compatibility and is further used in preparing an organic silicon sealant material, which helps to improve the mechanical strength of the organic silicon sealant material.

[0061] Alkoxy groups can form connections between interfaces, effectively improving the compatibility between fumed silica and vinyl silicone oil, allowing the fumed silica to be evenly dispersed, thereby reducing the viscosity of the silicone sealant material. The modified fumed silica also has vinyl -CH=CH2 on the surface, which can react with hydrogen-containing silicone oil during the curing process, making it easier to form a tight network structure, significantly improving the mechanical strength of the finished colloid product.

[0062] The invention also discloses the use of a compression permanent deformation controller in the preparation of a low compression permanent deformation organic silicon sealant.

[0063] A low compression set organic silicon sealant, comprising the following components in parts by weight:

[0064] 100 parts of vinyl silicone oil

[0065] Vinyl silicone resin 10-30 parts

[0066] 5-15 parts of hydrogen silicone oil

[0067] Surface modified gas silicon 20-50 parts

[0068] Flame retardant filler 20-35 parts

[0069] 1-3 parts of tackifier

[0070] Compression set control agent 1-3 parts

[0071] Catalyst 0.05-0.15 parts

[0072] Inhibitor 0.1-0.5 parts

[0073] 1-5 parts of phenylmethyl silicone oil.

[0074] The viscosity of vinyl silicone oil is 10000-50000cps.

[0075] The inhibitors are acetylenic alcohols and / or diallyl maleate.

[0076] The invention also discloses the application of low compression permanent deformation organic silicon sealant in the field of motor system control box or electrical appliance packaging.

[0077] Example 1

[0078] A compression set control agent having the molecular structure shown below:

[0079]

[0080] Wherein, R1 and R2 are methyl groups.

[0081] A method for preparing a compression set controlling agent comprises the following steps:

[0082] Step 1: In a nitrogen atmosphere, 120 g of p-phenylenediamine is diluted with 1000 g of toluene solvent to obtain a p-phenylenediamine solution, and the solution is transferred into a four-necked flask; 200 g of γ-chloropropyltrimethoxysilane and the first catalyst dilute hydrochloric acid are mixed, and the mixture is quickly added into a four-necked flask (with a reflux device) under nitrogen protection, and the mixture is first heated to 60° C., stirred for 1 hour, and then heated to 100° C., liquid reflux can be observed, and the mixture is kept warm for 2 hours, and then cooled to room temperature, and the solvent and side reaction products are removed by rotary evaporation to obtain the intermediate product;

[0083] Step 2: Dissolve 300g of the intermediate product and 150g of vinyltrimethoxysilane in 1000g of toluene, heat to 70°C under the action of the second catalyst Lewis acid, stir and react for 2h, cool to room temperature, and evaporate the solvent and side reaction products to obtain the compression set controller.

[0084] In step one, rapid heating will cause the movement speed of the reactant molecules to accelerate. Rapid temperature increase may cause the reaction to be too violent and cause danger. In addition, rapid heating will be accompanied by the production of by-products, and the production rate will be accelerated. Therefore, this embodiment first heats to 60°C and then to 100°C. By slowly heating, the production of by-products is reduced and the product purity is improved.

[0085] A method for preparing surface-modified gas silicon comprises the following steps:

[0086] Dissolve 1 part of compression set controller in 100 parts of toluene solvent, heat to 60°C, preheat for 30 minutes, then add 20 parts of dispersed fumed silica, stir at a stirring rate of 100r / min, heat to 80°C, react for 120 minutes, then cool to room temperature, filter out the solvent and alcohol products, and place in an oven for drying at a drying temperature of 110°C and a drying time of 50 minutes to obtain the desired surface-modified fumed silica.

[0087] A low compression set organic silicon sealant, comprising the following components in parts by weight:

[0088] 100 parts of vinyl silicone oil

[0089] Vinyl silicone resin 10 parts

[0090] 15 parts of hydrogen silicone oil

[0091] Surface modified silica 50 parts

[0092] 35 parts of flame retardant filler

[0093] Thickener 3 parts

[0094] 3 parts of compression set control agent

[0095] 0.15 parts of organic tin catalyst

[0096] 0.5 parts of acetylene alcohol inhibitor

[0097] 3 parts of phenylmethyl silicone oil.

[0098] The viscosity of vinyl silicone oil is 10000cps.

[0099] A method for preparing a low compression set silicone sealant comprises the following steps:

[0100] According to weight parts, 100 parts of vinyl silicone oil, 10 parts of vinyl silicone resin, 15 parts of hydrogenated silicone oil, 50 parts of surface modified gas silicon, 35 parts of aluminum hydroxide flame retardant filler, 3 parts of tackifier, 3 parts of compression permanent deformation controller, 0.15 parts of organic tin catalyst, 0.5 parts of acetylene alcohol inhibitor and 3 parts of benzyl silicone oil are mixed evenly in a planetary stirring kettle to obtain the desired low compression permanent deformation silicone sealant.

[0101] Example 2

[0102] A compression set control agent having the molecular structure shown below:

[0103]

[0104] Among them, R1 is methyl and R2 is ethyl.

[0105] A method for preparing a compression set controlling agent comprises the following steps:

[0106] Step 1: In a nitrogen atmosphere, 120 g of p-phenylenediamine is diluted with 1000 g of toluene solvent to obtain a p-phenylenediamine solution, and the solution is transferred into a four-necked flask; 230 g of γ-chloropropyltriethoxysilane and the first catalyst are mixed, and the mixture is quickly added into a four-necked flask (with a reflux device) under nitrogen protection, and the mixture is heated to 70° C., stirred for 1 hour, and then heated to 100° C., liquid reflux can be observed, and the mixture is kept warm for 1 hour, and then cooled to room temperature, and the solvent and side reaction products are removed by rotary evaporation to obtain the intermediate product;

[0107] Step 2: Dissolve 300g of the intermediate product and 150g of vinyltrimethoxysilane in 1000g of toluene, heat to 70°C under the action of a second catalyst, stir and react for 2h, cool to room temperature, and evaporate the solvent and side reaction products to obtain the compression set controller.

[0108] A method for preparing surface-modified gas silicon comprises the following steps:

[0109] The compression set controller was dissolved in toluene solvent, heated to 60°C, preheated for 30 minutes, and then the dispersed fumed silica was added and stirred at a stirring rate of 100 r / min. The temperature was raised to 80°C and reacted for 120 minutes. The mixture was then cooled to room temperature. After filtering out the solvent and alcohol products, the mixture was placed in an oven for drying at a drying temperature of 110°C and a drying time of 50 minutes to obtain the desired surface-modified fumed silica.

[0110] The rest is the same as in Example 1.

[0111] Example 3

[0112] A compression set control agent having the molecular structure shown below:

[0113]

[0114] Among them, R1 is methyl and R2 is propyl.

[0115] A method for preparing a compression set controlling agent comprises the following steps:

[0116] Step 1: In a nitrogen atmosphere, 120 g of p-phenylenediamine is diluted with 1000 g of toluene solvent to obtain a p-phenylenediamine solution, and the solution is transferred into a four-necked flask; 270 g of γ-chloropropyltriethoxysilane and the first catalyst are mixed, and the mixture is quickly added into a four-necked flask (with a reflux device) under nitrogen protection, and the mixture is heated to 60° C., stirred for 2 h, and then heated to 110° C., liquid reflux can be observed, and the mixture is kept warm for 1.5 h, and then cooled to room temperature, and the solvent and side reaction products are removed by rotary evaporation to obtain the intermediate product;

[0117] Step 2: Dissolve 300g of the intermediate product and 150g of vinyltrimethoxysilane in 1000g of toluene, heat to 70°C under the action of a second catalyst, stir and react for 2h, cool to room temperature, and evaporate the solvent and side reaction products to obtain the compression set controller.

[0118] A method for preparing surface-modified gas silicon comprises the following steps:

[0119] The compression set controller was dissolved in toluene solvent, heated to 60°C, preheated for 30 minutes, and then the dispersed fumed silica was added and stirred at a stirring rate of 100 r / min. The temperature was raised to 80°C and reacted for 120 minutes. The mixture was then cooled to room temperature. After filtering out the solvent and alcohol products, the mixture was placed in an oven for drying at a drying temperature of 110°C and a drying time of 50 minutes to obtain the desired surface-modified fumed silica.

[0120] The rest is the same as in Example 1.

[0121] Example 4

[0122] A compression set control agent having the molecular structure shown below:

[0123]

[0124] Wherein, R1 and R2 are both ethyl groups.

[0125] A method for preparing a compression set controlling agent comprises the following steps:

[0126] Step 1: In a nitrogen atmosphere, 120 g of p-phenylenediamine is diluted with 1000 g of toluene solvent to obtain a p-phenylenediamine solution, and the solution is transferred into a four-necked flask; 270 g of γ-chloropropyltriethoxysilane and the first catalyst are mixed, and the mixture is quickly added into a four-necked flask (with a reflux device) under nitrogen protection, and the mixture is heated to 60° C., stirred for 2 h, and then heated to 110° C., liquid reflux can be observed, and the mixture is kept warm for 1.5 h, and then cooled to room temperature, and the solvent and side reaction products are removed by rotary evaporation to obtain the intermediate product;

[0127] Step 2: 300 g of the intermediate product and 180 g of vinyltrimethoxysilane are dissolved in 1000 g of toluene, and heated to 70° C. under the action of a second catalyst, and stirred and reacted for 2 hours. After cooling to room temperature, the solvent and side reaction products are removed by rotary evaporation to obtain the compression set controller.

[0128] A method for preparing surface-modified gas silicon comprises the following steps:

[0129] The compression set controller was dissolved in toluene solvent, heated to 60°C, preheated for 30 minutes, and then the dispersed fumed silica was added and stirred at a stirring rate of 100 r / min. The temperature was raised to 80°C and reacted for 120 minutes. The mixture was then cooled to room temperature. After filtering out the solvent and alcohol products, the mixture was placed in an oven for drying at a drying temperature of 110°C and a drying time of 50 minutes to obtain the desired surface-modified fumed silica.

[0130] The rest is the same as in Example 1.

[0131] Comparative Example 1

[0132] The difference between this comparative example and Example 1 is that this comparative example uses octamethylcyclotetrasiloxane to replace the compression set control agent, and octamethylcyclotetrasiloxane has the molecular structure shown below:

[0133]

[0134] The rest is the same as in Example 1.

[0135] The compression set test method is based on GB / T 7759.1-2015, the curing conditions are 150℃, 30min, and the sample is made into a sample block with a diameter of 29mm±0.1mm and a thickness of 12.5mm±0.1mm. The thickness of the sample block is measured with a thickness gauge, recorded as h0; then the sample block height is compressed by 25% through a compression mold, recorded as hs; finally, the mold with the sample block is placed in a 150℃ oven, and the sample block is taken out after 72h, and cooled at room temperature for 30min, and then the height is tested, recorded as h1. The compression set calculation formula is:

[0136] C=[(h0-h1) / (h0-hs)]·100%.

[0137] The test methods for tensile strength and elongation at break are based on ISO 37, curing conditions: 150°C @ 30min, specimen requirements:

[0138] ① The width shall not be less than 30mm, the length shall not be less than 120mm, and the thickness shall be 2.0±0.2mm. For non-standard samples, the thickness shall not exceed 3mm;

[0139] ② The number of samples should be no less than 3. To reduce data error, it is recommended to use 5 samples;

[0140] ③ After the vulcanized test piece is left at room temperature for at least 16 hours, it is tested. The test steps are as follows:

[0141] 1) The stretching speed is set to 500 mm / min;

[0142] 2) Mark the test position according to the requirements. During the test, the fracture position of all samples should be within the marked area. If the fracture occurs outside the marked area, the data set should be discarded and re-sampled for testing;

[0143] 3) Test the sample thickness. The thickness should be averaged at three points within the marking area and input into the test equipment;

[0144] 4) Record the test data of each qualified sample, and record the elongation at break and tensile strength.

[0145] Hardness test method is based on ISO 868, curing conditions 150℃@30min, test piece requirements:

[0146] ① The thickness should be at least 4mm. The specimen can be composed of multiple layers of thinner specimens to obtain the necessary thickness, but the stacking may result in the problem that the multiple layers of specimens cannot be fully contacted, affecting the test results;

[0147] ② The perimeter / side length of the sample should be sufficient to allow measurement at least 9mm from any edge, and the sample surface should be flat in an area sufficient to allow the presser foot to contact the sample within a radius of at least 6mm from the indenter point. Hardness measurement cannot be performed on round, uneven or rough surfaces. The test steps are:

[0148] 1) Place the test piece on a hard, horizontal surface. Keep the hardness tester probe in a vertical position, with the indentation point at least 9 mm away from any edge of the sample;

[0149] 2) Press the presser foot onto the specimen as quickly as possible without vibration, keeping the presser foot parallel to the specimen surface. Apply enough pressure to ensure that the presser foot is in firm contact with the specimen.

[0150] 3) Read the scale of the indicating device after 15±1s;

[0151] 4) Carry out five hardness measurements at different locations on the specimen, with each test point separated by at least 6 mm, and determine the average value.

[0152] Shear strength (AL / AL) test is based on GB / T 7124-2008, curing conditions 150℃@30min, prepare the specimen, the bonding area length is 12.5mm±0.25mm, the test piece should be consistent with the cutting direction of the metal bonded parts; the thickness of the adhesive layer is 0.2mm, and the colloid overflowed during the bonding process should be handled in time. The specimen is clamped symmetrically on the fixture, and the distance from the holding point to the nearest end is 50±1mm. The tensile testing machine is tested at a constant test speed, and the maximum load of the specimen shear failure is recorded as the failure load.

[0153] The test results are shown in Table 1.

[0154] Table 1

[0155] Test items Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Tensile Strength 6.8 6.4 6.1 5.6 4.6 Elongation at break 410 435 452 478 325 hardness 45 42 38 36 52 Shear Strength 4.1 4.08 3.95 3.8 1.2 Compression set 16 23 25 28 38

[0156] It can be seen from Table 1 that:

[0157] The mechanical strength of Examples 1-4 is higher than that of Comparative Example 1. This is because the gas silicon (fumed silica) treated with vinyl trimethoxysilane has a certain amount of vinyl on its surface. During the reaction, the vinyl on the surface of the gas silicon reacts with the hydrogen-containing silicone oil to form a more compact network structure, which greatly improves the strength of the silicone sealant and improves the compression permanent deformation capacity. However, the gas silicon surface modified with octamethylcyclotetrasiloxane in Comparative Example 1 contains a certain amount of hydroxyl groups, which has poor binding ability with hydrogen-containing silicone oil and cannot form the above-mentioned compact network structure. Moreover, the viscosity-enhancing effect is too strong, the extrusion is poor, and the compression permanent deformation capacity is poor. At the same time, it can also be seen that in the gas silicon modification process, the reinforcing effect of the gas silicon modified with the compression permanent deformation controller is greatly improved. The short-chain compression permanent deformation controller has a more obvious effect on the strength improvement, and the strength gradually decreases as the chain length increases.

[0158] Parts or structures not specifically described in the present invention may adopt existing technologies or existing products and will not be described in detail here.

[0159] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A compression set controlling agent, characterized in that: The compression set controller has a molecular structure as shown below: Wherein, R1 and R2 are each selected from one of C1-C3 alkyl groups.

2. A compression set controlling agent according to claim 1, characterized in that: The compression set controller has a weight average molecular weight of 300-500, a viscosity of 100-1000 cps, and a vinyl content of 20%-30%.

3. A method for preparing a compression set controlling agent, characterized in that: The following steps are involved: Step 1: In a protective atmosphere, using γ-chloropropyltrialkoxysilane and p-phenylenediamine as raw materials, under the action of a first catalyst, a Cl substitution reaction is performed to prepare an intermediate product containing a benzene ring and an amino structure. The reaction equation is: Step 2: Using the intermediate product and vinyltrimethoxysilane as raw materials, under the action of the second catalyst, a condensation reaction is performed to prepare the desired compression set control agent. The reaction equation is:

4. The method for preparing a compression set controlling agent according to claim 3, characterized in that: In step 1, the molar ratio of γ-chloropropyltrialkoxysilane to p-phenylenediamine is 1:0.8-1.5; the temperature of the Cl substitution reaction is 80-120°C, and the time is 1-5h; the first catalyst is at least one of an organic tin catalyst, a titanate catalyst, and an acid catalyst, and the acid catalyst is dilute hydrochloric acid and / or dilute sulfuric acid.

5. The method for preparing a compression set controlling agent according to claim 3, characterized in that: In step 2, the molar ratio of the intermediate product to vinyltrimethoxysilane is 1:0.8-2; the temperature of the condensation reaction is 60-80°C, and the time is 2-6 hours; the second catalyst is at least one of a Lewis acid and a Lewis base.

6. Application of a compression set controller in the preparation of surface-modified silica.

7. A method for preparing surface-modified gas silicon, characterized in that: The following steps are involved: The compression set controller is dissolved in a solvent, heated to 50-70°C, preheated for 20-40 minutes, and then fumed silica is added, heated to 70-90°C, reacted for 100-150 minutes, cooled, and dried to obtain the desired surface-modified fumed silica.

8. The method for preparing surface-modified gas silicon according to claim 7, characterized in that: After adding the fumed silica, stirring is performed at a rate of 50-100 r / min, a drying temperature of 110-130° C., and a drying time of 50-70 min.

9. Application of a compression set controller in the preparation of low compression set silicone sealant.

10. A low compression set silicone sealant, characterized in that: According to parts by weight, it includes the following components: 100 parts of vinyl silicone oil Vinyl silicone resin 10-30 parts 5-15 parts of hydrogen silicone oil Surface modified gas silicon 20-50 parts Flame retardant filler 20-35 parts 1-3 parts of tackifier 1-3 parts of compression set controller Catalyst 0.05-0.15 parts Inhibitor 0.1-0.5 parts 1-5 parts of phenylmethyl silicone oil.

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