CN113831738A

CN113831738A - Addition type liquid silicone rubber foam material and preparation method thereof

Info

Publication number: CN113831738A
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: 2021-12-24
Anticipated expiration: 2041-09-28
Also published as: CN113831738B

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, the non-toxicity and the non-odor of the organosilicon material, has the high rebound resilience and the sound insulation and shock absorption of the foam material, and is generally applied to sound insulation, heat preservation, shock absorption, 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, the silicon rubber generates crosslinking reaction after being radiated by electron beams or rays, then the foaming agent is decomposed and foamed by heating, and secondary radiation crosslinking is carried out by adopting electron beams or rays after the silicon rubber is foamed, so as to further improve the comprehensive performance of the silicon rubber foam material. Chinese patent CN107141806B utilizes a silicone oil modification system to carry out bromination modification on silicone oil to prepare brominated 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 a nitroso foaming agent which can generate N₂、NH₃And 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 ratio, 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 comprises a foaming component and a crosslinking component as preparation raw materials;

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, Al (OH)₃、Mg(OH)₂、MgO、Al₂O₃At 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 2-20 parts of reinforcing filler by taking the total weight of the foaming component as 100 parts; the total weight of the crosslinking component is 100 parts, and the crosslinking component comprises 2-20 parts of reinforcing filler; the reinforcing filler is polyacrylonitrile-based carbon nano particles; the particle size 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 m²/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 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.

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 diagram of an 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 raw materials for preparing the addition type liquid silicone rubber foam material comprise foaming components. In the invention, the foaming component comprises 40-90 parts of vinyl silicone oil, preferably 64.95-86.92 parts of vinyl silicone oil, and more preferably 70.95-83.92 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 1000-10000 mPas, more preferably 3500-10000 mPas, and further preferably 7500-10000 mPas; the mass content of the vinyl group in the vinyl silicone oil is preferably 0.13 to 0.3%, more preferably 0.13 to 0.2%, and even more preferably 0.13 to 0.16%.

In the invention, the foaming component comprises 2-10 parts of hydroxyl silicone oil, preferably 4-8 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 5-15%.

In the present invention, the monohydroxy silicone oil is preferably polydimethylmonohydroxy siloxane; the hydroxyl content of the monohydroxy silicone oil is preferably 5-13%, and more preferably 7-10%. 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 content of the dihydroxy silicone oil is preferably 5-15%, and more preferably 8-13%. In the invention, when the hydroxyl silicone oil is dihydroxy silicone oil, the weight part of the hydroxyl silicone oil is preferably 2-6 parts, and more preferably 3-4.5 parts.

In the invention, the foaming component comprises 0.03-0.12 part of platinum catalyst, more preferably 0.05-0.08 part of platinum catalyst, and even more preferably 0.06-0.07 part of 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 content of Pt in the platinum catalyst is preferably 500-5000 ppm, and more preferably 500-3000 ppm.

In the invention, the foaming component comprises 1-16 parts of white carbon black, preferably 2-13 parts of white carbon black, more preferably 3-8 parts of white carbon black, and further preferably 3.5-5 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 m²(iv)/g, more preferably 180 to 220m²(ii) g, more preferably 200m²/g。

In the invention, the foaming component comprises 15-60 parts of flame-retardant filler, preferably 20-45 parts of flame-retardant filler, and more preferably 23.5-30 parts of flame-retardant filler, based on 100 parts of the total weight of the foaming component. In the present invention, the flame retardant preferably comprises a nitrogen-phosphorus flame retardant, Al (OH)₃、Mg(OH)₂、MgO、Al₂O₃At least one of glass powder, mica powder, kaolin and diatomite, more preferably Mg (OH)₂、Al(OH)₃Glass powder, mica powder and kaolin. In a particular embodiment of the invention, when the flame-retardant filler is Mg (OH)₂、Al(OH)₃Glass powder, mica powder and kaolin, wherein the Mg (OH)₂、Al(OH)₃The 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 invention, the foaming component preferably further comprises 2-20 parts of reinforcing filler, preferably 3-15 parts of 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 100-500 nm, and more preferably 120-160 nm.

The raw materials for preparing the addition type liquid silicone rubber foam material comprise a crosslinking component. In the invention, the crosslinking component comprises 10-70 parts of vinyl silicone oil, preferably 20-50 parts of vinyl silicone oil, and more preferably 30-35 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 1000-10000 mPas, more preferably 3500-10000 mPas, and further preferably 5000-10000 mPas; the mass content of the vinyl group in the vinyl silicone oil is preferably 0.13 to 0.3%, more preferably 0.13 to 0.2%, and even more preferably 0.13 to 0.16%.

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

In the invention, the crosslinking component comprises 1-30 parts of white carbon black, preferably 3-20 parts of white carbon black, and more preferably 5-15 parts of white carbon black based on 100 parts of the total weight of the crosslinking 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 m²(iv)/g, more preferably 180 to 220m²(ii) g, more preferably 200m²/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 invention, the crosslinking component comprises 1-30 parts of flame-retardant filler, preferably 3-20 parts of flame-retardant filler, and more preferably 5-15 parts of flame-retardant filler, based on 100 parts of the total weight of the crosslinking component. In the present invention, the flame retardant preferably comprises a nitrogen-phosphorus flame retardant, Al (OH)₃、Mg(OH)₂、MgO、Al₂O₃At least one of glass powder, mica powder, kaolin and diatomite, more preferably Mg (OH)₂、Al(OH)₃And glass powder. In the present invention, when the flame-retardant filler is Mg (OH)₂、Al(OH)₃When the flame-retardant filler is compounded with glass powder, the Mg (OH)₂、Al(OH)₃The mass ratio of the glass powder to the glass powder is preferably 7.5:2.5: 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 invention, the crosslinking component preferably further comprises 2-20 parts of reinforcing filler, preferably 3-15 parts, 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 200 nm.

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

The density of the addition type liquid silicone rubber foam material provided by the invention is preferably 0.2864-5411 g/cm³More preferably 0.2864 to 0.4757g/cm³(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 654 kPa; the elongation at break is preferably 76-114%, and more preferably 84-55.6%; the 25% compressive stress is preferably 10.2 to 55.6kPa, and more preferably 18.6 to 55.6 kPa; the permanent compression set is preferably 1-10%, more preferably 3-5%; the vertical burning grade is preferably V0 grade, and the oxygen index is preferably 28.2-31.6%, and more preferably 29.0-31.2%.

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 odor, 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 60 min. According to the invention, preferably, after the mixing, the obtained mixed system is filtered by a filter screen of 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 60 min. According to the invention, preferably, after the mixing, the obtained mixed system is filtered by a filter screen of 200-400 meshes, and the obtained filter residue is a crosslinking component.

The invention stirs the mixed material at high speed in relative vacuum environment, which not only reduces the bubbles brought in during the mixing process, but also can mix the base glue with higher viscosity evenly.

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 invention, the mixing temperature of the foaming component and the crosslinking component is preferably-40-10 ℃, and more preferably-20-10 ℃. The invention mixes the foaming component and the crosslinking component at low temperature, can prevent the foaming component from vulcanizing and foaming at room 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 30 min; 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 invention, the heat preservation time of each temperature gradient is preferably 3-5 min. In a specific embodiment of the present invention, the temperature rising 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 18 min.

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 shape 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 is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. 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 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: 59.45 parts of vinyl-terminated polydimethylsiloxane (viscosity 10000mPa & s, vinyl content 0.13 wt%); 6.5 parts of polydimethylmonohydroxysiloxane (with the hydroxyl content being 7%); 0.05 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 200 m)²Per gram) 3.5 parts; mg (OH)₂7.5 parts; al (OH)₃2.5 parts; 15.5 parts of glass powder; 2.5 parts of mica powder; 2.5 parts of kaolin;

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 (the hydrogen content is 1.6 wt%); fumed silica (200 m)²Per g)10 parts; mg (OH)₂7.5 parts; al (OH)₃2.5 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 foaming components, the vinyl-terminated polydimethylsiloxane, the polydimethylsiloxane monohydroxy, the platinum-vinyl siloxane complex, the fumed silica, Mg (OH)₂、Al(OH)₃Placing 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 polydimethyl siloxaneAlkane, hydrogen-containing silicone oil, fumed silica, Mg (OH)₂、Al(OH)₃Mixing with glass powder in a planetary stirrer at a rotation speed of 100r/min under a vacuum degree of-80 kPa for 60min to be 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 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/cm³The expansion ratio was 1.63, the tensile strength was 645kPa, the elongation at break was 94%, the 25% compressive stress was 41.2kPa, the permanent compression set was 5%, the vertical flame rating was V0, and the oxygen index was 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, wherein the foaming component comprises the following materials in parts by mass based on 100 parts by weight of the total 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)²Per 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 (the hydrogen content is 1.6 wt%); fumed silica (200 m)²Per g)10 parts; nitrogen-phosphorus flame retardant (Dalou chemical industry Limited)15 parts of flame retardant 6003).

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, wherein the heating process is divided into four gradients, setting the temperatures 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 silicon rubber foam material.

The addition type liquid silicone rubber foam material prepared in this example had a density of 0.3476g/cm³The 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 flame 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%); polydimethyl ether6.5 parts of monohydroxy 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)²Per g)5 parts; 23.5 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 (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)²Per g)5 parts; 5 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry 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/cm³Expansion ratio of2.16 times, tensile strength 503kPa, elongation at break 88%, 25% compressive stress 55.6kPa, permanent compression set 3%, vertical flame rating V0, oxygen index 29.0%. The cell morphology is shown in figure 1. The oxygen index of the addition type liquid silicone rubber foam material is improved with the increase of the amount of the flame retardant compared with example 2.

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 (viscosity 10000mPa & s, vinyl content 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)²Per gram) 2.5 parts; 30 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 (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)²Per g)5 parts; 10 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical Co., Ltd.).

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/cm³The 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 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: 60.7 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)²Per 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 (viscosity 10000mPa & s, vinyl content 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-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., Ltd.).

The addition type liquid silicone rubber foam material prepared in this example had a density of 0.4638g/cm³Comparative example 4, in which the expansion ratio was 1.74 times, the tensile strength was 434kPa, the elongation at break was 85%, the 25% compressive stress was 42.3kPa, the permanent compression set was 3%, the vertical burning rating was V0, and the oxygen index was 29.2%, hydrogen-containing silicone oil acted as a crosslinking agent in the preparation of an addition type liquid silicone rubber foam, and the tensile strength was decreased as the amount of the hydrogen-containing silicone oil as a crosslinking component was decreased.

Example 6

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: 54.95 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); poly dimethyl monohydroxy silicon6 parts of 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)²Per 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 (viscosity 10000mPa & s, vinyl content 0.13 wt%); 80 parts of hydrogen-containing silicone oil (the hydrogen content is 1.6 wt%); fumed silica (200 m)²Per 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 had a density of 0.5411g/cm³Expansion ratio of 1.60 times, and tensile strength of 332kPa, elongation at break 92%, 25% compressive stress 49.6kPa, permanent compression set 5%, vertical burn rating V0, oxygen index 31.0%.

Example 7

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: 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%); 0.04 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 150 m)²Per gram) 2 parts; 20 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., Ltd.); 7.5 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 (viscosity 10000mPa & s, vinyl content 0.13 wt%); 75 parts of hydrogen-containing silicone oil (the hydrogen content is 1.6 wt%); fumed silica (150 +/-15 m)²Per g)5 parts; 5 parts of nitrogen-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, 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 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/cm³The 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 flame 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)²Per 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 (viscosity 10000mPa & s, vinyl content 0.13 wt%); 75 parts of hydrogen-containing silicone oil (hydrogen content is 1.2 wt%); fumed silica (180 m)²Per g)3 parts; 5 parts of nitrogen-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 polydimethylsiloxane-terminated, 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 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/cm³The 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 flame rating was V0, and the oxygen index was 30.8%.

Example 9

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: 58.96 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 8000mPa & s and the vinyl content of 0.15 wt%); 3.5 parts of polydimethyl-terminated hydroxyl siloxane (the hydroxyl content is 8%); platinum-vinyl siloxane formulations0.04 part of compound (Pt content 3000 ppm); fumed silica (specific surface area 180 m)²Per gram) 2.5 parts; 23 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry 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 (the hydrogen content is 1.2 wt%); fumed silica (180 m)²Per g)5 parts; 5 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry Co., Ltd.); 10 parts of polyacrylonitrile-based carbon nano particles (120 nm).

Addition type liquid Silicone rubber prepared in this exampleA gel foam material having a density of 0.4752g/cm³The 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 flame rating was V0, and the oxygen index was 31.2%.

Example 10

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: 60.94 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)²Per g)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 (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)²Per g)3 parts; 3 parts of nitrogen-phosphorus flame retardant (flame retardant 6003 of Dalton chemical industry 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/cm³The 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%, the vertical flame rating was V0, and the oxygen index was 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, wherein the foaming component comprises the following materials in parts by mass based on 100 parts by weight of the total foaming component: 61.95 parts of vinyl-terminated polydimethylsiloxane (viscosity 10000mPa & s, vinyl content 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)²Per g)3 parts; 31.5 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 (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)²Per 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 silicon rubber foam material.

The addition type liquid silicone rubber foam material prepared in this example had a density of 0.4725g/cm³The 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 flame 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 monohydroxy silicone oil used 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, wherein the foaming component comprises the following materials in parts by mass based on 100 parts by weight of the total foaming component: 60.45 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); poly (dimethyl)6.5 parts of monohydroxy siloxane (the hydroxyl content is 7 percent); 0.05 part of a platinum-vinylsiloxane complex (Pt content 3000 ppm); fumed silica (specific surface area 180 m)²Per g)3 parts; al (OH)₃30 parts of (1);

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking 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 (the hydrogen content is 1.6 wt%); fumed silica (180 m)²Per g)5 parts; al (OH)₃And 20 parts.

according to the material composition of foaming components, the vinyl-terminated polydimethylsiloxane, the platinum-vinyl siloxane complex, the fumed silica and Al (OH)₃Placing the mixture in a planetary stirrer with the rotation speed of 100r/min under the condition of vacuum degree of-80 kPa, mixing for 60min until the mixture is uniform, 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 Al (OH)₃Mixing in a planetary stirrer with rotation speed of 100r/min under vacuum degree of-80 kPa for 60min to mix uniformly, 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 silicon rubber foam material.

In CN109762342A example 2, Al (OH) is added in the same amount as in the example₃The vertical burning grade is V1 grade, the oxygen index is 26.8 percent, the flame retardant grade does not reach V0 grade, and the grade is in the real gradeIn example 1, the same parts of the compound flame retardant are added, and the oxygen index can reach 29.7%. It can be seen that Al (OH) is added separately₃The 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 performance, and the oxygen index is taken as one of important parameters for evaluating the flame retardant performance, 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 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: 70.94 parts of vinyl-terminated polydimethylsiloxane (viscosity 10000mPa & s, vinyl content 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)²Per 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)²Per 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 has the density of 0.3606g/cm without adding polyacrylonitrile-based carbon nano particles and changing other components³The foaming ratio is 2.10 times, the tensile strength is 368kPa, the elongation at break 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%.

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)²Per g)8 parts;

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking component: 30 parts of vinyl-terminated polydimethylsiloxane (with the viscosity of 10000mPa & s and the vinyl content of 0.13 wt%); containing hydrogen silicon50 parts of oil (with the hydrogen content of 1.6 wt%); fumed silica (200 m)²Per 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, 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 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;

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/cm³The 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 flame 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, wherein the foaming component comprises the following materials in parts by mass based on 100 parts by weight of the total foaming component: vinyl-terminated polydimethylsiloxane (viscosity 10000 mPa. multidot.s, vinyl content 0.13 wt%)86.92 parts of a binder; 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)²Per g)5 parts;

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking 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)²Per g)20 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/cm³The 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 flame 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 1-4, with the addition of the flame retardant, the pore wall of the cell becomes thicker, 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 further burning, 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 (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); precipitated silica white (specific surface area 380 m)²Per g)5 parts;

the crosslinking component comprises the following materials in parts by mass based on 100 parts by weight of the total crosslinking 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%); precipitated silica (380 m)²Per g)20 parts.

The addition-type liquid silicone rubber foam obtained in this comparative example had a density of 0.4547g/cm³Compared with the comparative example 2, the untreated white carbon black has poor dispersibility in the liquid silicone rubber matrix and larger particle size, obstructs cell growth, causes the foaming ratio of the liquid silicone rubber to be reduced, increases the density, and is not beneficial to generating fine and uniform cells.

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;

2. the addition type liquid silicone rubber foam material according to claim 1, wherein the flame retardant comprises nitrogen phosphorus flame retardant, Al (OH)₃、Mg(OH)₂、MgO、Al₂O₃At least one of glass powder, mica powder, kaolin and diatomite.

3. The addition liquid silicone rubber foam according to claim 1, wherein the foaming component and crosslinking component further comprise a reinforcing filler; the foaming component comprises 2-20 parts of reinforcing filler by taking the total weight of the foaming component as 100 parts; the total weight of the crosslinking component is 100 parts, and the crosslinking component comprises 2-20 parts of reinforcing filler;

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

4. The addition type liquid silicone rubber foam material according to claim 1, wherein the white carbon black is fumed silica; the specific surface area of the white carbon black is 135-440 m²/g。

5. The addition 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.

6. 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%.

7. 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%.

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

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

10. The preparation method of claim 9, wherein 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.