CN113831738B

CN113831738B - Addition type liquid silicone rubber foam material and preparation method thereof

Info

Publication number: CN113831738B
Application number: CN202111140523.2A
Authority: CN
Inventors: 张会轩; 刘朵朵; 付中禹; 徐哲; 闫慧洁; 王春奇
Original assignee: Changchun University of Technology
Current assignee: Changchun University of Technology
Priority date: 2021-09-28
Filing date: 2021-09-28
Publication date: 2023-02-28
Anticipated expiration: 2041-09-28
Also published as: CN113831738A

Abstract

The invention provides an addition type liquid silicone rubber foam material and a preparation method thereof, and relates to the technical field of high polymer materials. The raw materials used in the invention are nontoxic and harmless, and the foaming component and the crosslinking component are separated, so that the foaming and crosslinking matching performance is better, the foaming multiplying power of the addition type liquid silicone rubber foam material can be improved, and the addition type liquid silicone rubber foam material has higher mechanical property and flame retardant property; according to the invention, through the reaction of the hydroxyl silicone oil and the hydrogen-containing silicone oil, the generated gas is non-toxic and tasteless hydrogen, and compared with the gas with pungent odor such as nitrogen, ammonia and the like generated by the traditional rubber compound, the product of the invention is more environment-friendly. In addition, the preparation process is simple and easy to operate, and is beneficial to industrial production.

Description

Addition type liquid silicone rubber foam material and preparation method thereof

Technical Field

The invention relates to the technical field of high polymer materials, in particular to an addition type liquid silicone rubber foam material and a preparation method thereof.

Background

The organosilicon is a compound containing Si-C bonds and at least one organic group which is directly connected with silicon atoms, wherein 90 percent of the main chain is composed of silicon-oxygen bonds alternately, the side chain is generally methyl, methylene, vinyl and other organic groups, and the organosilicon has the excellent characteristics of high and low temperature resistance, electrical insulation, oxidation resistance, nonflammability, no toxicity, no odor, physiological compatibility and the like, and is widely applied to the fields of aerospace, electronics and electricity, industrial buildings, transportation, medical chemical industry and the like. The organosilicon foam material combines the characteristics of the organosilicon material and the foam material, has the high-temperature resistance, non-toxicity and non-odor properties of the organosilicon material, has the high resilience and sound insulation and vibration reduction properties of the foam material, and is generally applied to sound insulation, heat preservation, vibration reduction, sealing, water prevention and the like.

Addition-type liquid silicone rubber foams are generally of the type which are crosslinkable and vulcanizable at room temperature or under heat in the presence of platinum catalysts, based on vinyl-containing polyorganosiloxanes and of polyorganosiloxanes containing Si-H bonds as crosslinking agents. Chinese patent CN101781464A mixes silicon rubber with reinforcing agent, foaming agent and other auxiliary agents, after electron beam or ray radiation, the silicon rubber generates crosslinking reaction, then the foaming agent is decomposed and foamed by heating, after the silicon rubber is foamed, secondary radiation crosslinking is performed by adopting electron beam or ray, so as to further improve the comprehensive performance of the silicon rubber foam material. Chinese patent CN107141806B uses a silicone oil modification system to brominate and modify silicone oil to prepare brominated and modified silicone oil; then mixing and reacting the brominated modified silicone oil, the foaming agent, the reinforcing agent, the catalyst and the cross-linking agent to prepare the silicone rubber foam material.

The silicon rubber foam material has poor flame retardant property, and most of rubber compound uses nitrite foaming agent, so that N can be generated ₂ 、NH ₃ And the modification process is complex and long in time consumption, and is not beneficial to large-scale production.

Disclosure of Invention

The addition type liquid silicone rubber foam material provided by the invention has the advantages of excellent mechanical property, good flame retardant property, high foaming rate, no toxicity, no odor, simple processing technology, low cost and the like, and is suitable for popularization and application.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides an addition type liquid silicone rubber foam material, which is prepared from the following raw materials of a foaming component and a crosslinking component;

the foaming component comprises the following raw materials in parts by weight, based on 100 parts by weight of the total weight of the foaming component:

the crosslinking component comprises the following raw materials in parts by weight, based on 100 parts of the total weight of the crosslinking component:

the mass ratio of the foaming component to the crosslinking component is 1-10: 1.

preferably, the flame retardant comprises nitrogen phosphorus flame retardant and Al (OH) ₃ 、Mg(OH) ₂ 、MgO、Al ₂ O ₃ At least one of glass powder, mica powder, kaolin and diatomite.

Preferably, the foaming component and the crosslinking component further comprise a reinforcing filler; the foaming component comprises 2 to 20 parts of reinforcing filler by taking the total weight of the foaming component as 100 parts; the crosslinking component comprises 2 to 20 parts of reinforcing filler by taking the total weight of the crosslinking component as 100 parts; the reinforcing filler is polyacrylonitrile-based carbon nano particles; the grain diameter of the reinforcing filler is 100-500 nm.

Preferably, the white carbon black is fumed silica; the specific surface area of the white carbon black is 135-440 m ² /g。

Preferably, the platinum catalyst is a platinum-vinylsiloxane complex; the Pt content in the platinum catalyst is 500-5000 ppm.

Preferably, the vinyl silicone oil is vinyl-terminated polydimethylsiloxane; the viscosity of the vinyl silicone oil is 1000-10000 mPa.s; the mass content of vinyl groups in the vinyl silicone oil is 0.13-0.3%.

Preferably, the hydroxyl silicone oil is monohydroxy silicone oil or dihydroxy silicone oil; the hydroxyl content of the hydroxyl silicone oil is 5-15%.

Preferably, the hydrogen content of the hydrogen-containing silicone oil is 0.2-1.6 wt%.

The invention provides a preparation method of the addition type liquid silicone rubber foam material, which comprises the following steps:

mixing the raw materials of the foaming component to obtain the foaming component;

mixing the raw materials of the crosslinking component to obtain the crosslinking component;

and mixing the foaming component and the crosslinking component to obtain a rubber material, and sequentially carrying out first-stage vulcanization foaming and second-stage high-temperature vulcanization on the rubber material to obtain the addition type liquid silicone rubber foam material.

Preferably, the temperature of the first-stage vulcanization foaming is 35-55 ℃, and the time of the first-stage vulcanization foaming is 20-50 min; the temperature of the second-stage high-temperature vulcanization is 100-180 ℃, and the time of the second-stage high-temperature vulcanization is 40 min-2 h.

The invention provides an addition type liquid silicone rubber foam material, the raw materials used in the invention are nontoxic and harmless, and the foaming component and the crosslinking component are separated, so that the foaming and crosslinking matching performance is better, the foaming multiplying power of the addition type liquid silicone rubber foam material can be improved, and the addition type liquid silicone rubber foam material has higher mechanical property and flame retardant property; according to the invention, through the reaction of the hydroxyl silicone oil and the hydrogen-containing silicone oil, the generated gas is non-toxic and tasteless hydrogen, and compared with the gas with pungent odor such as nitrogen, ammonia and the like generated by the traditional rubber compound, the product of the invention is more environment-friendly. In addition, the preparation process is simple and easy to operate, and is beneficial to industrial production.

Drawings

FIG. 1 is a cell morphology diagram of an addition type liquid silicone rubber foam prepared in example 3;

FIG. 2 is a cell morphology of the addition type liquid silicone rubber foam prepared in example 4;

FIG. 3 is a cell morphology diagram of an addition type liquid silicone rubber foam material prepared in comparative example 1;

FIG. 4 is a cell morphology map of the addition-type liquid silicone rubber foam prepared in comparative example 2.

Detailed Description

The invention provides an addition type liquid silicone rubber foam material, which comprises a foaming component and a crosslinking component as preparation raw materials;

based on 100 parts of the total weight of the foaming components, the foaming components comprise the following raw materials in parts by weight:

the raw materials for preparing the addition type liquid silicone rubber foam material comprise foaming components. In the present invention, the foaming component includes 40 to 90 parts, preferably 64.95 to 86.92 parts, and more preferably 70.95 to 83.92 parts of vinyl silicone oil, based on 100 parts of the total weight of the foaming component. In the present invention, the vinyl silicone oil is preferably vinyl-terminated polydimethylsiloxane; the viscosity of the vinyl silicone oil is preferably 1000 to 10000 mPas, more preferably 3500 to 10000 mPas, and further preferably 7500 to 10000 mPas; the vinyl silicone oil preferably contains a vinyl group in an amount of 0.13 to 0.3% by mass, more preferably 0.13 to 0.2% by mass, and still more preferably 0.13 to 0.16% by mass.

In the present invention, the foaming component includes 2 to 10 parts, preferably 4 to 8 parts of hydroxyl silicone oil, based on 100 parts of the total weight of the foaming component. In the present invention, the hydroxy silicone oil is preferably a monohydroxy silicone oil or a bishydroxy silicone oil; the hydroxyl content of the hydroxyl silicone oil is preferably 5 to 15 percent.

In the present invention, the monohydroxy silicone oil is preferably polydimethylmonohydroxy siloxane; the hydroxyl group content of the monohydroxy silicone oil is preferably 5 to 13%, more preferably 7 to 10%. In the present invention, when the hydroxy silicone oil is a monohydroxy silicone oil, the weight part of the hydroxy silicone oil is preferably 3 to 10 parts, and more preferably 6.5 to 8 parts.

In the present invention, the bishydroxy silicone oil is preferably polydimethyl-terminated hydroxysiloxane; the hydroxyl group content of the bishydroxy silicone oil is preferably 5 to 15%, more preferably 8 to 13%. In the present invention, when the hydroxy silicone oil is a bishydroxy silicone oil, the weight part of the hydroxy silicone oil is preferably 2 to 6 parts, and more preferably 3 to 4.5 parts.

In the present invention, the foaming component includes 0.03 to 0.12 part, more preferably 0.05 to 0.08 part, and still more preferably 0.06 to 0.07 part of a platinum catalyst, based on 100 parts of the total weight of the foaming component. In the present invention, the platinum catalyst is preferably a platinum-vinylsiloxane complex; the Pt content in the platinum catalyst is preferably 500 to 5000ppm, and more preferably 500 to 3000ppm.

In the present invention, the foaming component comprises 1 to 16 parts of white carbon black, preferably 2 to 13 parts of white carbon black, more preferably 3 to 8 parts of white carbon black, and even more preferably 3.5 to 5 parts of white carbon black, based on 100 parts of the total weight of the foaming component. In the invention, the white carbon black is preferably fumed silica; the specific surface area of the white carbon black is preferably 135-440 m ² (ii) g, more preferably 180 to 220m ² (ii) g, more preferably 200m ² /g。

In the present invention, the foaming component includes 15 to 60 parts, preferably 20 to 45 parts, and more preferably 23.5 to 30 parts of the flame retardant filler, based on 100 parts of the total weight of the foaming component. In the present invention, the flame retardant preferably includes nitrogen phosphorus flame retardant, al (OH) ₃ 、Mg(OH) ₂ 、MgO、Al ₂ O ₃ At least one of glass powder, mica powder, kaolin and diatomite, more preferably Mg (OH) ₂ 、Al(OH) ₃ Glass powder, mica powder and kaolin. In a particular embodiment of the invention, when the flame-retardant filler is Mg (OH) ₂ 、Al(OH) ₃ Glass powder, mica powder and kaolin, and Mg (OH) ₂ 、Al(OH) ₃ The mass ratio of the glass powder to the mica powder to the kaolin is 7.5:2.5:10:2.5:2.5; in the invention, the nitrogen-phosphorus flame retardant preferably comprises a phosphate and a derivative compound thereof. In a specific embodiment of the present invention, the nitrogen-phosphorus flame retardant is a flame retardant 6003 of dalong chemical industry limited.

In the present invention, the foaming component preferably further comprises 2 to 20 parts, preferably 3 to 15 parts, of a reinforcing filler, based on 100 parts of the total weight of the foaming component. In the present invention, the reinforcing filler is preferably polyacrylonitrile-based carbon nanoparticles; the particle size of the reinforcing filler is preferably from 100 to 500nm, more preferably from 120 to 160nm.

The raw materials for preparing the addition type liquid silicone rubber foam material comprise a crosslinking component. In the present invention, the crosslinking component includes 10 to 70 parts, preferably 20 to 50 parts, and more preferably 30 to 35 parts of vinyl silicone oil, based on 100 parts of the total weight of the crosslinking component. In the present invention, the vinyl silicone oil is preferably vinyl-terminated polydimethylsiloxane; the viscosity of the vinyl silicone oil is preferably 1000 to 10000 mPas, more preferably 3500 to 10000 mPas, and further preferably 5000 to 10000 mPas; the vinyl silicone oil preferably contains a vinyl group in an amount of 0.13 to 0.3% by mass, more preferably 0.13 to 0.2% by mass, and still more preferably 0.13 to 0.16% by mass.

In the present invention, the crosslinking component includes 20 to 90 parts, preferably 40 to 80 parts, and more preferably 50 to 80 parts of hydrogen-containing silicone oil, based on 100 parts of the total weight of the crosslinking component. In the present invention, the hydrogen content of the hydrogen-containing silicone oil is preferably 0.2 to 1.6wt%, more preferably 0.5 to 1.2wt%.

In the present invention, the crosslinking component is present in an amount of 100 parts by weight based on the total weight of the crosslinking componentThe white carbon black is 1 to 30 parts, preferably 3 to 20 parts, and more preferably 5 to 15 parts. In the invention, the white carbon black is preferably fumed silica; the specific surface area of the white carbon black is preferably 135-440 m ² A ratio of 180 to 220 m/g is more preferable ² (ii) g, more preferably 200m ² /g。

In the invention, the fumed silica has small particle size, chemical inertness and special thixotropic property, and can obviously improve the tensile strength of the liquid silicone rubber, thereby effectively improving the mechanical property of the silicone rubber; the surface of the untreated white carbon black has a large amount of hydroxyl groups, and the direct addition of the hydroxyl groups can generate an agglomeration phenomenon.

In the present invention, the crosslinking component includes 1 to 30 parts, preferably 3 to 20 parts, and more preferably 5 to 15 parts of the flame retardant filler, based on 100 parts of the total weight of the crosslinking component. In the present invention, the flame retardant preferably comprises nitrogen phosphorus flame retardant, al (OH) ₃ 、Mg(OH) ₂ 、MgO、Al ₂ O ₃ At least one of glass powder, mica powder, kaolin and diatomaceous earth, more preferably Mg (OH) ₂ 、Al(OH) ₃ And glass powder. In the present invention, when the flame retardant filler is Mg (OH) ₂ 、Al(OH) ₃ And glass powder, the Mg (OH) ₂ 、Al(OH) ₃ And the glass frit preferably has a mass ratio of 7.5. In the invention, the nitrogen-phosphorus flame retardant preferably comprises a phosphate and a derivative compound thereof. In a specific embodiment of the invention, the nitrogen-phosphorus flame retardant is a flame retardant 6003 of dalton chemical co.

In the present invention, the crosslinking component preferably further comprises 2 to 20 parts, preferably 3 to 15 parts, of a reinforcing filler, based on 100 parts of the total weight of the crosslinking component. In the present invention, the reinforcing filler is preferably polyacrylonitrile-based carbon nanoparticles; the particle size of the reinforcing filler is preferably 100 to 500nm, more preferably 120 to 300nm, and still more preferably 160 to 200nm.

The invention adopts the polyacrylonitrile-based carbon nano particles as the reinforcing filler, the filler has small particle size, good reinforcing effect and hydrophobicity, can be effectively dispersed in the liquid silicone rubber base rubber, improves the mechanical property, can also improve the limit oxygen index value and improve the flame retardance of the material, and the cost of the polyacrylonitrile-based carbon nano particles is lower than that of the white carbon black, so that the liquid silicone rubber foam material can be more widely applied and has lower cost.

In the present invention, the mass ratio of the foaming component to the crosslinking component is preferably 1 to 10:1, more preferably 2 to 8.

The density of the addition type liquid silicon rubber foam material provided by the invention is preferably 0.2864-5411 g/cm ³ More preferably 0.2864 to 0.4757g/cm ³ (ii) a The expansion ratio is preferably 1.6 to 2.71, more preferably 1.69 to 2.71; the tensile strength is preferably 128 to 654kPa, more preferably 332 to 654kPa; the elongation at break is preferably 76 to 114%, more preferably 84 to 55.6%; the 25% compressive stress is preferably 10.2 to 55.6kPa, more preferably 18.6 to 55.6kPa; the permanent compression set is preferably 1 to 10%, more preferably 3 to 5%; the vertical burning class is preferably V0 class, and the oxygen index is preferably 28.2 to 31.6%, more preferably 29.0 to 31.2%.

and mixing the foaming component and the crosslinking component to obtain a sizing material, and sequentially carrying out first-stage vulcanization foaming and second-stage high-temperature vulcanization to obtain the addition type liquid silicone rubber foam material.

The addition type liquid silicone rubber foam material is obtained through one-stage vulcanization foaming and two-stage high-temperature vulcanization, and the addition type liquid silicone rubber foam material prepared by the method is low in density, uniform in foam pores, good in mechanical property and excellent in flame retardant property. The preparation method has the advantages of simple and easy operation of the preparation process, low cost, no toxicity and no smell, and is suitable for large-scale production.

The foaming component is obtained by mixing the raw materials of the foaming component. In the present invention, the mixing is preferably carried out in an environment of a relative vacuum degree of-90 to-40 kPa, and the introduction of a large amount of bubbles by stirring can be prevented. In the present invention, the relative degree of vacuum is more preferably-80 kPa. In the invention, the mixing is preferably carried out in a planetary stirrer, and the rotating speed is preferably 100-150 r/min; the mixing time was 60min. In the invention, preferably, after the mixing, the obtained mixed system is filtered by a filter screen with 200-400 meshes, and the obtained filter residue is a foaming component. The invention removes impurities in the mixed system by filtration.

The invention mixes the raw materials of the crosslinking component to obtain the crosslinking component. In the present invention, the mixing is preferably carried out in an environment of a relative vacuum degree of-90 to-40 kPa, and the introduction of a large amount of bubbles by stirring can be prevented. In the invention, the mixing is preferably carried out in a planetary stirrer, and the rotating speed is preferably 100-200 r/min; the mixing time was 60min. In the invention, preferably, after the mixing, the obtained mixed system is filtered by a filter screen with 200-400 meshes, and the obtained filter residue is a crosslinking component.

The invention stirs the mixed materials at high speed in a relatively vacuum environment, thereby not only reducing bubbles brought in the mixing process, but also uniformly mixing the base rubber with higher viscosity.

In the present invention, the foaming component and the crosslinking component are stored at room temperature after the preparation thereof is completed.

After the foaming component and the crosslinking component are obtained, the foaming component and the crosslinking component are mixed, and the obtained rubber material is subjected to first-stage vulcanization foaming and second-stage high-temperature vulcanization in sequence to obtain the addition type liquid silicone rubber foam material. In the present invention, the temperature at which the foaming component and the crosslinking component are mixed is preferably-40 to 10 deg.C, and more preferably-20 to-10 deg.C. The invention can prevent the foaming component and the crosslinking component from vulcanizing and foaming at room temperature by mixing the foaming component and the crosslinking component at low temperature, and is not beneficial to subsequent operation. In the present invention, the mixing of the foaming component and the crosslinking component is preferably carried out in a rubber mixer.

In the present invention, the one-stage vulcanization foaming and the two-stage high-temperature vulcanization are preferably performed in a mold covered with a release film. In the invention, the temperature of the first-stage vulcanization foaming is preferably 35-55 ℃, and more preferably 50 ℃; the time for the first-stage vulcanization foaming is preferably 20-50 min, and more preferably 30min; the temperature of the two-stage high-temperature vulcanization is preferably 100-180 ℃, more preferably 110-170 ℃, and further preferably 130 ℃; the time of the two-stage high-temperature vulcanization is preferably 40 min-2 h, and more preferably 45 min-1.5 h.

In the invention, the temperature from the first-stage vulcanization foaming temperature to the second-stage high-temperature vulcanization temperature is preferably increased in sections, and 3-6 gradients are set at intervals of 20 ℃ as one gradient. In the present invention, the holding time for each temperature gradient is preferably 3 to 5min. In a specific embodiment of the present invention, the temperature rise time from the temperature of the first stage vulcanization foaming to the temperature of the second stage high temperature vulcanization is preferably 15 to 20min, and more preferably 18min.

In the process of preparing the addition type liquid silicone rubber foam material, the low-temperature foaming vulcanization is carried out firstly, then the high-temperature secondary vulcanization is carried out, and the vulcanization and the foaming are better matched, so that the prepared foam has uniform foam holes, high foaming multiplying power, small density, low compression permanent deformation and better comprehensive performance.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It should be apparent that the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

In the embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, wherein the foaming component comprises the following materials in parts by mass based on 100 parts by weight of the total foaming component: 59.45 portions of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000 mPa.s and the vinyl content of 0.13 weight percent); 6.5 parts of polydimethylmonohydroxysiloxane (with the hydroxyl content being 7 percent); 0.05 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 200 m) ² Per gram) 3.5 parts; mg (OH) ₂ 7.5 parts; al (OH) ₃ 2.5 parts; 15.5 parts of glass powder; 2.5 parts of mica powder; 2.5 parts of kaolin;

the cross-linking component comprises the following materials in parts by mass based on 100 parts of the total weight of the cross-linking component: 35 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 40 parts of hydrogen-containing silicone oil (hydrogen content is 1.6 wt%); fumed silica (200 m) ² Per gram) 10 parts; mg (OH) ₂ 7.5 parts; al (OH) ₃ 2.5 parts; and 5 parts of glass powder.

The preparation method of the addition type liquid silicone rubber foam material comprises the following steps:

according to the material composition of the foaming component, the vinyl-terminated polydimethylsiloxane, the polydimethylsiloxane monohydroxy, the platinum-vinyl siloxane complex, the fumed silica and Mg (OH) ₂ 、Al(OH) ₃ Placing the glass powder, the mica powder and the kaolin in a planetary stirrer with the rotation speed of 100r/min under the condition that the vacuum degree is-80 kPa, mixing for 60min until the mixture is uniformly mixed, and filtering by using a 200-mesh filter screen to obtain a foaming component;

according to the material composition of the crosslinking component, the vinyl-terminated polydimethylsiloxane, the hydrogen-containing silicone oil, the fumed silica and Mg (OH) ₂ 、Al(OH) ₃ Mixing with glass powder in a planetary stirrer with the rotation speed of 100r/min under the condition of the vacuum degree of-80 kPa for 60min until the mixture is uniformly mixed, and filtering by using a filter screen with 200 meshes to obtain a crosslinking component; the foaming component and the crosslinking component are stored at room temperature;

and (2) mixing the foaming component and the crosslinking component according to the mass ratio of 10:1, mixing, uniformly mixing in a rubber mixing machine at the temperature of minus 10 ℃, placing in a tunnel furnace, setting the temperature at 50 ℃ for low-temperature vulcanization foaming, staying for 30min, then heating, dividing the heating process into six gradients, setting the temperatures at 70 ℃, 90 ℃, 110 ℃, 130 ℃, 150 ℃ and 170 ℃ respectively, staying for 3min at each temperature, and finally placing at 170 ℃ for vulcanization for 1.5h to obtain the addition type liquid silicone rubber foam material.

The addition type liquid silicone rubber foam material prepared in the example has the density of 0.5021g/cm ³ Expansion ratio1.63 times, tensile strength 645kPa, elongation at break 94%,25% compressive stress 41.2kPa, permanent compression set 5%, vertical burning rating V0, oxygen index 29.7%.

Example 2

In this embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, mixing, wherein the foaming component comprises the following materials in parts by mass based on 100 parts of the total weight of the foaming component: 70.95 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 6 parts of polydimethylmonohydroxy siloxane (the hydroxyl content is 7 percent); 0.05 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 200 m) ² Per g) 3 parts; 20 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.);

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking component: 35 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 40 parts of hydrogen-containing silicone oil (hydrogen content is 1.6 wt%); fumed silica (200 m) ² Per g) 10 parts; 15 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical Co., ltd.).

according to the material composition of the foaming component, putting the vinyl-terminated polydimethylsiloxane, the polydimethylsiloxane monohydroxy, the platinum-vinylsiloxane complex, the fumed silica and the nitrogen-phosphorus flame retardant in a planetary stirrer with the rotation speed of 100r/min under the condition of vacuum degree of-80 kPa for mixing for 60min until the mixture is uniformly mixed, and filtering the mixture by using a 200-mesh filter screen to obtain the foaming component;

according to the material composition of the crosslinking component, the vinyl-terminated polydimethylsiloxane, the hydrogen-containing silicone oil, the fumed silica and the nitrogen-phosphorus flame retardant are mixed in a planetary stirrer with the rotation speed of 100r/min for 60min under the condition of the vacuum degree of-80 kPa until the mixture is uniformly mixed, and a 200-mesh filter screen is used for filtering to obtain the crosslinking component; the foaming component and the crosslinking component are stored at room temperature;

and (2) mixing the foaming component and the crosslinking component according to the mass ratio of 10:1, mixing, uniformly mixing in a rubber mixing machine at the temperature of minus 10 ℃, placing in a tunnel furnace, setting the temperature at 50 ℃ for low-temperature vulcanization foaming, staying for 30min, then heating, dividing the heating process into four gradients, setting the temperatures at 70 ℃, 90 ℃, 110 ℃ and 130 ℃ respectively, staying for 5min at each temperature, and finally placing at 130 ℃ for vulcanization for 50min to obtain the addition type liquid silicone rubber foam material.

The addition type liquid silicone rubber foam material prepared in this example had a density of 0.3476g/cm ³ The expansion ratio was 2.32 times, the tensile strength was 466kPa, the elongation at break was 84%, the 25% compressive stress was 43.9kPa, the permanent compression set was 5%, the vertical burn rating was V0, and the oxygen index was 28.2%.

Example 3

In this embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, wherein the foaming component comprises the following materials in parts by mass based on 100 parts by weight of the total foaming component: 64.94 parts of vinyl-terminated polydimethylsiloxane (viscosity 10000mPa & s, vinyl content 0.13 wt%); 6.5 parts of polydimethylmonohydroxysiloxane (with the hydroxyl content being 7%); 0.06 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 220 m) ² Per g) 5 parts; 23.5 parts of nitrogen and phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.);

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking component: 10 parts of vinyl-terminated polydimethylsiloxane (viscosity 10000mPa & s, vinyl content 0.13 wt%); 80 parts of hydrogen-containing silicone oil (the hydrogen content is 1.6 wt%); fumed silica (220 m) ² Per gram) 5 parts; 5 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical Co., ltd.).

according to the material composition of the crosslinking component, the vinyl-terminated polydimethylsiloxane, the hydrogen-containing silicone oil, the fumed silica and the nitrogen-phosphorus flame retardant are mixed in a planetary stirrer with the rotation speed of 200r/min for 60min under the condition that the vacuum degree is 80kPa to be uniform, and a 200-mesh filter screen is used for filtering to obtain the crosslinking component; the foaming component and the crosslinking component are stored at room temperature;

The addition type liquid silicone rubber foam material prepared in this example had a density of 0.3558g/cm ³ The expansion ratio was 2.16 times, the tensile strength was 503kPa, the elongation at break was 88%, the 25% compressive stress was 55.6kPa, the permanent compression set was 3%, the vertical burn rating was V0, and the oxygen index was 29.0%. The cell morphology is shown in figure 1. Compared with example 2, the oxygen index of the addition type liquid silicone rubber foam material is improved with the increase of the amount of the flame retardant.

Example 4

In this embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, wherein the foaming component comprises the following materials in parts by mass based on 100 parts by weight of the total foaming component: 60.96 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 6.5 parts of polydimethylmonohydroxysiloxane (with the hydroxyl content being 7%); 0.04 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 220 m) ² Per gram) 2.5 parts; nitrogen phosphorus flame retardant (Dalou chemical industry limited)Company flame retardant 6003) 30 parts;

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking component: 10 parts of vinyl-terminated polydimethylsiloxane (viscosity 10000mPa & s, vinyl content 0.13 wt%); 75 parts of hydrogen-containing silicone oil (the hydrogen content is 1.6 wt%); fumed silica (220 m) ² Per gram) 5 parts; 10 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical Co., ltd.).

according to the material composition of the foaming component, placing the vinyl-terminated polydimethylsiloxane, the platinum-vinyl siloxane complex, the fumed silica and the nitrogen-phosphorus flame retardant in a planetary stirrer with the rotation speed of 100r/min under the condition that the vacuum degree is 80kPa below zero for mixing for 60min until the mixture is uniformly mixed, and filtering the mixture by using a 200-mesh filter screen to obtain the foaming component;

according to the material composition of the crosslinking component, the vinyl-terminated polydimethylsiloxane, the hydrogen-containing silicone oil, the fumed silica and the nitrogen-phosphorus flame retardant are mixed in a planetary stirrer with the rotation speed of 100r/min for 60min under the condition that the vacuum degree is 80kPa below zero for uniform mixing, and a 200-mesh filter screen is used for filtering to obtain the crosslinking component; the foaming component and the crosslinking component are stored at room temperature;

and (2) mixing the foaming component and the crosslinking component according to the mass ratio of 10:1, mixing, uniformly mixing in a rubber mixing machine at the temperature of minus 20 ℃, placing in a tunnel furnace, setting the temperature at 50 ℃ for low-temperature vulcanization foaming, staying for 30min, then heating, wherein the heating process is divided into three gradients, the temperatures are respectively set at 70 ℃, 90 ℃ and 110 ℃, staying for 5min at each temperature, and finally placing at 110 ℃ for vulcanization for 1h to obtain the addition type liquid silicone rubber foam material.

The addition type liquid silicone rubber foam material prepared in this example had a density of 0.4384g/cm ³ The expansion ratio was 1.87 times, the tensile strength was 487kPa, the elongation at break was 78%, the 25% compressive stress was 43.5kPa, the permanent compression set was 2.5%, the vertical burning rating was V0, and the oxygen index was 29.4%. The cell morphology is shown in figure 2.

Example 5

In the embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, wherein the foaming component comprises the following materials in parts by mass based on 100 parts by weight of the total foaming component: 60.7 parts of vinyl-terminated polydimethylsiloxane (viscosity of 7500mPa & s, vinyl content of 0.15 wt%); 6 parts of polydimethylmonohydroxy siloxane (the hydroxyl content is 7 percent); 0.05 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 200 m) ² Per g) 4 parts; 29.25 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.);

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking component: 15 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 70 parts of hydrogen-containing silicone oil (the hydrogen content is 1.6 wt%); fumed silica (200 m) ² /g) 7.5 parts; 7.5 parts of nitrogen and phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.).

The addition type liquid silicone rubber foam material prepared in this example has a density of 0.4638g/cm ³ Comparative example 4, hydrogen-containing silicone oil in the preparation of addition type liquid silicone rubber foam material, which has a foaming ratio of 1.74 times, a tensile strength of 434kPa, an elongation at break of 85%, a 25% compressive stress of 42.3kPa, a permanent compression set of 3%, a vertical burning rating of V0, and an oxygen index of 29.2%, has a crosslinking effect, and the tensile strength is decreased as the amount of the hydrogen-containing silicone oil as a crosslinking component is decreased.

Example 6

In the embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, mixing, wherein the foaming component comprises the following materials in parts by mass based on 100 parts of the total weight of the foaming component: 54.95 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 6 parts of polydimethylmonohydroxy siloxane (the hydroxyl content is 7 percent); 0.05 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 200 m) ² Per g) 4 parts; 35 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.);

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking component: 10 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 80 parts of hydrogen-containing silicone oil (the hydrogen content is 1.6 wt%); fumed silica (200 m) ² Per gram) 2.5 parts; 7.5 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.).

The addition type liquid silicone rubber foam material prepared in this example has a density of 0.5411g/cm ³ The expansion ratio was 1.60 times, the tensile strength was 332kPa, the elongation at break was 92%, the 25% compressive stress was 49.6kPa, the permanent compression set was 5%, the vertical burning rating was V0, and the oxygen index was 31.0%.

Example 7

In the embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, mixing, wherein the foaming component comprises the following materials in parts by mass based on 100 parts of the total weight of the foaming component: 62.96 parts of vinyl-terminated polydimethylsiloxane (viscosity 10000mPa & s, vinyl content 0.13 wt%); 7.5 parts of polydimethylmonohydroxysiloxane (with the hydroxyl content being 7 percent); 0.04 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 150 m) ² Per gram) 2 parts; 20 parts of nitrogen and phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.); 7.5 parts of polyacrylonitrile-based carbon nano particles (120 nm);

based on 100 parts of the total weight of the crosslinking components, the crosslinking components areThe following materials in parts by mass: 10 parts of vinyl-terminated polydimethylsiloxane (viscosity 10000mPa & s, vinyl content 0.13 wt%); 75 parts of hydrogen-containing silicone oil (hydrogen content is 1.6 wt%); fumed silica (150 +/-15 m) ² Per g) 5 parts; 5 parts of nitrogen and phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.); 5 parts of polyacrylonitrile-based carbon nano particles (120 nm).

according to the material composition of the foaming component, putting the vinyl-terminated polydimethylsiloxane, the polydimethylsiloxane monohydroxy, the platinum-vinylsiloxane complex, the fumed silica, the nitrogen-phosphorus flame retardant and the polyacrylonitrile-based carbon nano-particles in a planetary stirrer with the rotating speed of 100r/min under the condition of the vacuum degree of-80 kPa for mixing for 60min until the mixture is uniformly mixed, and filtering the mixture by using a 200-mesh filter screen to obtain the foaming component;

according to the material composition of the crosslinking component, the vinyl-terminated polydimethylsiloxane, the hydrogen-containing silicone oil, the fumed silica, the nitrogen-phosphorus flame retardant and the polyacrylonitrile-based carbon nanoparticles are mixed in a planetary stirrer with the rotation speed of 100r/min for 60min under the condition that the vacuum degree is 80kPa to be uniform, and the mixture is filtered by a 200-mesh filter screen to obtain the crosslinking component; the foaming component and the crosslinking component are stored at room temperature;

and (2) mixing the foaming component and the crosslinking component according to the mass ratio of 10:1, mixing, uniformly mixing in a rubber mixing machine at the temperature of minus 20 ℃, placing in a tunnel furnace, setting the temperature at 50 ℃ for low-temperature vulcanization foaming, staying for 30min, then heating, wherein the heating process is divided into four gradients, the temperatures are respectively set at 70 ℃, 90 ℃, 110 ℃ and 130 ℃, staying for 5min at each temperature, and finally placing at 130 ℃ for vulcanization for 45min to obtain the addition type liquid silicone rubber foam material.

The addition type liquid silicone rubber foam material prepared in this example had a density of 0.4474g/cm ³ The expansion ratio was 1.78 times, the tensile strength was 604kPa, the elongation at break was 97%, the 25% compressive stress was 45.3kPa, the permanent compression set was 5%, the vertical burn rating was V0, and the oxygen index was 30.6%.

Example 8

In this embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, wherein the foaming component comprises the following materials in parts by mass based on 100 parts by weight of the total foaming component: 64.95 parts of vinyl-terminated polydimethylsiloxane (viscosity 10000mPa & s, vinyl content 0.13 wt%); 3 parts of polydimethyl-terminated hydroxyl siloxane (the hydroxyl content is 8%); 0.05 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 180 m) ² Per gram) 2.5 parts; 22 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.); 7.5 parts of polyacrylonitrile-based carbon nano particles (160 nm);

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking component: 10 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 75 parts of hydrogen-containing silicone oil (hydrogen content is 1.2 wt%); fumed silica (180 m) ² Per gram) 3 parts; 5 parts of nitrogen and phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.); 7 parts of polyacrylonitrile-based carbon nano particles (160 nm).

according to the material composition of the foaming component, putting the vinyl-terminated polydimethylsiloxane, the polydimethyl-terminated hydroxyl siloxane, the platinum-vinyl siloxane complex, the fumed silica, the nitrogen-phosphorus flame retardant and the polyacrylonitrile-based carbon nano particles in a planetary stirrer with the rotating speed of 100r/min under the condition of the vacuum degree of-80 kPa for mixing for 60min until the mixture is uniformly mixed, and filtering the mixture by using a 200-mesh filter screen to obtain the foaming component;

The addition type liquid silicone rubber foam material prepared in this example had a density of 0.4529g/cm ³ The expansion ratio was 1.76 times, the tensile strength was 619kPa, the elongation at break was 98%, the 25% compressive stress was 50.5kPa, the permanent compression set was 3%, the vertical burning rating was V0, and the oxygen index was 30.8%.

Example 9

In the embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, mixing, wherein the foaming component comprises the following materials in parts by mass based on 100 parts of the total weight of the foaming component: 58.96 parts of vinyl-terminated polydimethylsiloxane (viscosity 8000mPa & s, vinyl content 0.15 wt%); 3.5 parts of polydimethyl-terminated hydroxyl siloxane (the hydroxyl content is 8 percent); 0.04 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 180 m) ² Per gram) 2.5 parts; 23 parts of a nitrogen-phosphorus flame retardant (a flame retardant 6003 from Dalton chemical Co., ltd.); 12 parts of polyacrylonitrile-based carbon nano particles (120 nm);

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking component: 10 parts of vinyl-terminated polydimethylsiloxane (the viscosity is 8000mPa & s, and the vinyl content is 0.15 wt%); 70 parts of hydrogen-containing silicone oil (with the hydrogen content of 1.2 wt%); fumed silica (180 m) ² Per gram) 5 parts; 5 parts of nitrogen and phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.); 10 parts of polyacrylonitrile-based carbon nano particles (120 nm).

The addition type liquid silicone rubber foam material prepared in this example has a density of 0.4752g/cm ³ The expansion ratio was 1.69, the tensile strength was 648kPa, the elongation at break was 106%, the 25% compressive stress was 53.3kPa, the permanent compression set was 3%, the vertical burning class was V0, and the oxygen index was 31.2%.

Example 10

In the embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, mixing, wherein the foaming component comprises the following materials in parts by mass based on 100 parts of the total weight of the foaming component: 60.94 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 6 parts of polydimethylmonohydroxy siloxane (the hydroxyl content is 7 percent); 0.06 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 220 m) ² Per gram) 3 parts; 20 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.); 10 parts of polyacrylonitrile-based carbon nano particles (200 nm);

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking component: 10 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 80 parts of hydrogen-containing silicone oil (hydrogen content is 1.2 wt%); fumed silica (220 m) ² Per gram) 3 parts; 3 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical Co., ltd.); 4 parts of polyacrylonitrile-based carbon nano particles (200 nm).

The addition type liquid silicone rubber foam material prepared in this example had a density of 0.4573g/cm ³ The expansion ratio was 1.75 times, the tensile strength was 654kPa, the elongation at break was 114%, the 25% compressive stress was 51.5kPa, the permanent compression set was 5%, and the vertical flame rating wasV0 grade, oxygen index 31.6%.

Example 11

In this embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, mixing, wherein the foaming component comprises the following materials in parts by mass based on 100 parts of the total weight of the foaming component: 61.95 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 3.5 parts of polydimethyl-terminated hydroxyl siloxane (the hydroxyl content is 8%); 0.05 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 180 m) ² Per gram) 3 parts; 31.5 parts of nitrogen and phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.);

the cross-linking component comprises the following materials in parts by mass based on 100 parts of the total weight of the cross-linking component: 15 parts of vinyl-terminated polydimethylsiloxane (viscosity 10000mPa & s, vinyl content 0.13 wt%); 70 parts of hydrogen-containing silicone oil (the hydrogen content is 1.6 wt%); fumed silica (180 m) ² Per g) 5 parts; 10 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical Co., ltd.).

according to the material composition of the foaming component, putting the vinyl-terminated polydimethylsiloxane, the polydimethylsiloxane-terminated polydimethylsiloxane, the platinum-vinylsiloxane complex, the fumed silica and the nitrogen-phosphorus flame retardant in a planetary stirrer with the rotation speed of 100r/min under the condition of vacuum degree of-80 kPa for mixing for 60min until the mixture is uniformly mixed, and filtering the mixture by using a 200-mesh filter screen to obtain the foaming component;

and (2) mixing the foaming component and the crosslinking component according to the mass ratio of 10:1, mixing, uniformly mixing in a rubber mixing machine at the temperature of minus 20 ℃, placing in a tunnel furnace, setting the temperature at 50 ℃ for low-temperature vulcanization foaming, staying for 30min, then heating, wherein the heating process is divided into four gradients, the temperatures are respectively set at 70 ℃, 90 ℃, 110 ℃ and 130 ℃, staying for 5min at each temperature, and finally placing at 130 ℃ for vulcanization for 50min to obtain the addition type liquid silicone rubber foam material.

The addition type liquid silicone rubber foam material prepared in this example has a density of 0.4725g/cm ³ The expansion ratio was 1.73 times, the tensile strength was 503kPa, the elongation at break was 97%, the 25% compressive stress was 42.6kPa, the permanent compression set was 5%, the vertical burning rating was V0, and the oxygen index was 30.2%. In this example, a bishydroxy silicone oil was used, and the tensile strength was increased as compared with the case of using the monohydroxy silicone oil in example 4.

Example 12 comparative patent CN109762342A example 2

In this embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, mixing, wherein the foaming component comprises the following materials in parts by mass based on 100 parts of the total weight of the foaming component: 60.45 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 6.5 parts of polydimethylmonohydroxysiloxane (with the hydroxyl content being 7 percent); 0.05 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 180 m) ² Per gram) 3 parts; al (OH) ₃ 30 parts of (1);

the cross-linking component comprises the following materials in parts by mass based on 100 parts of the total weight of the cross-linking component: 5 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 70 parts of hydrogen-containing silicone oil (with the hydrogen content of 1.6 wt%); fumed silica (180 m) ² Per g) 5 parts; al (OH) ₃ And 20 parts.

according to the material composition of the foaming component, the vinyl-terminated polydimethylsiloxane, the polydimethylsiloxane monohydroxy, the platinum-vinyl siloxane complex, the fumed silica and Al (OH) ₃ Placing the mixture in a planetary stirrer with the rotation speed of 100r/min for mixing under the condition that the vacuum degree is-80 kPaMixing for 60min, and filtering with 200 mesh filter screen to obtain foaming component;

according to the material composition of the crosslinking component, the vinyl-terminated polydimethylsiloxane, the hydrogen-containing silicone oil, the fumed silica and Al (OH) ₃ Mixing in a planetary stirrer with rotation speed of 100r/min for 60min under vacuum degree of-80 kPa until the mixture is uniformly mixed, and filtering with a 200-mesh filter screen to obtain a crosslinking component; the foaming component and the crosslinking component are stored at room temperature;

and (2) mixing the foaming component and the crosslinking component according to the mass ratio of 10:1, mixing, uniformly mixing in a rubber mixing machine at the temperature of minus 20 ℃, placing in a tunnel furnace, setting the temperature at 50 ℃ for low-temperature vulcanization foaming, staying for 30min, then heating, dividing the heating process into six gradients, setting the temperatures at 70 ℃, 90 ℃, 110 ℃, 130 ℃, 150 ℃ and 170 ℃ respectively, staying for 5min at each temperature, and finally placing at 170 ℃ for vulcanization for 50min to obtain the addition type liquid silicone rubber foam material.

Patent CN109762342A in example 2, the same portion of Al (OH) is added as in this example ₃ The vertical burning grade is V1 grade, the oxygen index is 26.8 percent, the oxygen index does not reach the flame retardant grade V0 grade, and in the embodiment 1, the same parts of the compound flame retardant are added, and the oxygen index can reach 29.7 percent. It can be seen that Al (OH) is added separately ₃ The flame retardant effect is not ideal, in addition, in patent CN109762342A, only vertical combustion is taken as a single standard for judging the flame retardant property, and the oxygen index is taken as one of important parameters for evaluating the flame retardant property, the liquid silicon rubber foam prepared by the compound flame retardant has good flame retardant effect, the oxygen index can reach 31.6%, the foam holes are uniform, and the mechanical property is excellent.

Example 13

In the embodiment, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, wherein the foaming component comprises the following materials in parts by mass based on 100 parts by weight of the total foaming component: 70.94 portions of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000 mPa.s and the vinyl content of 0.13 weight percent); 6 parts of polydimethylmonohydroxy siloxane (the hydroxyl content is 7 percent); platinum-vinyl siloxane complexes (Pt containingAmount 3000 ppm) 0.06 parts; fumed silica (specific surface area 220 m) ² Per g) 3 parts; 20 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., ltd.);

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking component: 14 parts of vinyl-terminated polydimethylsiloxane (viscosity 10000mPa & s, vinyl content 0.13 wt%); 80 parts of hydrogen-containing silicone oil (hydrogen content is 1.2 wt%); fumed silica (220 m) ² Per g) 3 parts; 3 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical Co., ltd.).

according to the material composition of the crosslinking component, the vinyl-terminated polydimethylsiloxane, the hydrogen-containing silicone oil, the fumed silica and the nitrogen-phosphorus flame retardant are mixed in a planetary stirrer with the rotation speed of 100r/min for 60min under the condition that the vacuum degree is 80kPa to be uniform, and a 200-mesh filter screen is used for filtering to obtain the crosslinking component; the foaming component and the crosslinking component are stored at room temperature;

The addition type liquid silicone rubber foam material obtained in the embodiment is not added with polyacrylonitrile-based carbon nano particles, other components are not changed, and the density is 0.3606g/cm ³ Foaming ratio 2.10 times, tensile strength 368kPa, elongation at breakThe elongation is 94%, the 25% compressive stress is 40.8kPa, the permanent compression set is 5%, the vertical burning grade is V0 grade, and the oxygen index is 27.1%, compared with the example 10, the density is reduced, the foaming ratio is increased, but the tensile strength is reduced by 286kPa, the 25% compressive stress is reduced by 10.7kPa, and the oxygen index is reduced by 4.5%, thus the mechanical property and the flame retardant property of the polyacrylonitrile-based carbon nano-particle are improved by adding the polyacrylonitrile-based carbon nano-particle.

Comparative example 1

In the comparative example, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, wherein the foaming component comprises the following materials in parts by mass based on 100 parts by weight of the total foaming component: 83.92 parts of vinyl-terminated polydimethylsiloxane (viscosity 10000mPa & s, vinyl content 0.13 wt%); 8 parts of polydimethylmonohydroxysiloxane (with the hydroxyl content being 7%); 0.08 part of a platinum-vinylsiloxane complex (Pt content 500 ppm); fumed silica (specific surface area 200 m) ² Per g) 8 parts;

the cross-linking component comprises the following materials in parts by mass based on 100 parts of the total weight of the cross-linking component: 30 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 50 parts of hydrogen-containing silicone oil (the hydrogen content is 1.6 wt%); fumed silica (200 m) ² Per g) 20 parts.

The preparation method of the addition type liquid silicone rubber foam material of the comparative example comprises the following steps:

according to the material composition of the foaming component, putting the vinyl-terminated polydimethylsiloxane, the polydimethylsiloxane monohydroxy, the platinum-vinylsiloxane complex and the fumed silica in a planetary stirrer with the rotation speed of 100r/min under the condition that the vacuum degree is 80kPa for 60min to be uniformly mixed, and filtering the mixture by using a 200-mesh filter screen to obtain the foaming component;

according to the material composition of the crosslinking component, mixing the vinyl-terminated polydimethylsiloxane, the hydrogen-containing silicone oil and the fumed silica in a planetary stirrer with the rotation speed of 100r/min under the condition of the vacuum degree of-80 kPa for 60min until the mixture is uniformly mixed, and filtering the mixture by using a 200-mesh filter screen to obtain the crosslinking component; the foaming component and the crosslinking component are stored at room temperature;

and (2) mixing the foaming component and the crosslinking component according to the mass ratio of 10:1, mixing, uniformly mixing in a rubber mixing machine at the temperature of minus 10 ℃, placing in a tunnel furnace, setting the temperature at 50 ℃ for low-temperature vulcanization foaming, staying for 30min, then heating, wherein the heating process is divided into three gradients, the temperatures are respectively set at 70 ℃, 90 ℃ and 110 ℃, staying for 5min at each temperature, and finally placing at 110 ℃ for vulcanization for 1h to obtain the addition type liquid silicone rubber foam material.

The addition type liquid silicone rubber foam material prepared by the comparative example has the density of 0.3181g/cm ³ The expansion ratio was 2.26 times, the tensile strength was 158kPa, the elongation at break was 88%, the 25% compressive stress was 13.5kPa, the permanent compression set was 3%, the vertical combustion rating was V2, and the oxygen index was 24.2%. The cell morphology is shown in figure 3.

Comparative example 2

In the comparative example, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, mixing, wherein the foaming component comprises the following materials in parts by mass based on 100 parts of the total weight of the foaming component: 86.92 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 8 parts of polydimethylmonohydroxysiloxane (with the hydroxyl content being 7%); 0.08 part of a platinum-vinylsiloxane complex (Pt content 500 ppm); fumed silica (specific surface area 200 m) ² Per g) 5 parts;

according to the material composition of the crosslinking component, the vinyl-terminated polydimethylsiloxane, the hydrogen-containing silicone oil and the fumed silica are mixed in a planetary stirrer with the rotation speed of 100r/min for 60min under the condition that the vacuum degree is-90 kPa until the mixture is uniformly mixed, and a 200-mesh filter screen is used for filtering to obtain the crosslinking component; the foaming component and the crosslinking component are stored at room temperature;

The addition type liquid silicone rubber foam material prepared by the comparative example has the density of 0.2864g/cm ³ The expansion ratio was 2.71 times, the tensile strength was 128kPa, the elongation at break was 76%, the 25% compressive stress was 10.2kPa, the permanent compression set was 3%, the vertical burning rating was V0, and the oxygen index was 25.4%. The cell morphology is shown in figure 4.

As can be seen from the comparison of figures 1 to 4, the pore wall of the cell becomes thicker with the addition of the flame retardant, so that the mechanical property of the cell is improved, and in addition, the thickness of the pore wall is increased, so that the liquid silicone rubber foam is prevented from being further combusted, and the flame retardant property of the liquid silicone rubber foam is improved.

Comparative example 3

In the comparative example, the addition-type liquid silicone rubber foam material comprises a foaming component and a crosslinking component in a mass ratio of 10:1, wherein the foaming component comprises the following materials in parts by mass based on 100 parts by weight of the total foaming component: 86.92 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 8 parts of polydimethylmonohydroxy siloxane (the hydroxyl content is 7%); 0.08 part of a platinum-vinylsiloxane complex (Pt content 500 ppm); precipitated silica white (specific surface area 380 m) ² Per g) 5 parts;

based on the total weight of the crosslinking components as 100 parts,the crosslinking component consists of the following materials in parts by mass: 30 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); 50 parts of hydrogen-containing silicone oil (the hydrogen content is 1.6 wt%); white carbon black (380 m) by precipitation method ² Per g) 20 parts.

according to the material composition of the crosslinking component, the vinyl-terminated polydimethylsiloxane, the hydrogen-containing silicone oil, the fumed silica, the nitrogen-phosphorus flame retardant and the polyacrylonitrile-based carbon nanoparticles are mixed in a planetary stirrer with the rotation speed of 100r/min for 60min under the condition that the vacuum degree is-80 kPa until the mixture is uniformly mixed, and the mixture is filtered by a 200-mesh filter screen to obtain the crosslinking component; the foaming component and the crosslinking component are stored at room temperature;

The addition-type liquid silicone rubber foam material obtained in the comparative example has a density of 0.4547g/cm ³ The foaming ratio is 1.78 times, the tensile strength is 167kPa, the elongation at break is 96%, the 25% compressive stress is 12.6kPa, and the permanent compression set is 5%, compared with the comparative example 2, the untreated white carbon black has poor dispersibility in the liquid silicone rubber base rubber and larger particle size, obstructs the cell growth, causes the reduction of the foaming ratio of the liquid silicone rubber foam, increases the density, and is not beneficial to the generation of fine and uniformThe cells of (2).

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. An addition type liquid silicone rubber foam material is characterized in that the preparation raw material comprises a foaming component and a crosslinking component;

the mass ratio of the foaming component to the crosslinking component is 1-10: 1;

the foaming component and the crosslinking component also comprise reinforcing filler; based on 100 parts of the total weight of the foaming components, the foaming components comprise 2-20 parts of reinforcing filler; the crosslinking component comprises 2 to 20 parts of reinforcing filler by taking the total weight of the crosslinking component as 100 parts;

the reinforcing filler is polyacrylonitrile-based carbon nano particles; the grain size of the reinforcing filler is 100-500 nm;

mixing the foaming component and the crosslinking component to obtain a rubber material, and sequentially carrying out first-stage vulcanization foaming and second-stage high-temperature vulcanization on the rubber material to obtain an addition type liquid silicone rubber foam material;

the temperature of the first-stage vulcanization foaming is 35-55 ℃, and the time of the first-stage vulcanization foaming is 20-50 min; the temperature of the second-stage high-temperature vulcanization is 100-180 ℃, and the time of the second-stage high-temperature vulcanization is 40 min-2 h;

heating up the temperature of the first-stage vulcanization foaming to the temperature of the second-stage high-temperature vulcanization in a sectional manner, wherein 3-6 gradients are set at intervals of 20 ℃; the heat preservation time of each temperature gradient is 3-5 min.

2. The addition type liquid silicone rubber foam material as claimed in claim 1, wherein the flame retardant comprises nitrogen phosphorus flame retardant, al (OH) ₃ 、Mg(OH) ₂ 、MgO、Al ₂ O ₃ At least one of glass powder, mica powder, kaolin and diatomite.

3. The addition type liquid silicone rubber foam material according to claim 1, characterized in that the white carbon black is fumed white carbon black; the specific surface area of the white carbon black is 135-440 m ² /g。

4. The addition type liquid silicone rubber foam material according to claim 1, wherein the platinum catalyst is a platinum-vinylsiloxane complex; the Pt content in the platinum catalyst is 500-5000 ppm.

5. The addition type liquid silicone rubber foam material according to claim 1, wherein the vinyl silicone oil is vinyl terminated polydimethylsiloxane; the viscosity of the vinyl silicone oil is 1000-10000 mPa.s; the mass content of vinyl groups in the vinyl silicone oil is 0.13-0.3%.

6. The addition type liquid silicone rubber foam material according to claim 1, characterized in that the hydroxy silicone oil is monohydroxy silicone oil or bishydroxy silicone oil; the hydroxyl content of the hydroxyl silicone oil is 5-15%.

7. The addition type liquid silicone rubber foam material as set forth in claim 1, wherein the hydrogen content of said hydrogen-containing silicone oil is 0.2 to 1.6wt%.

8. A process for the preparation of an addition type liquid silicone rubber foam material as defined in any one of claims 1 to 7, comprising the steps of: