CN107446357A - A kind of low-density micropore diameter silicon rubber composite material and preparation method thereof - Google Patents

Abstract

The invention relates to the field of silicone rubber, in particular to a low-density and small-aperture silicone rubber composite material and a preparation method thereof. The silicone rubber composite material is composed of the following raw materials in weight percentage: 100 parts of vinyl polysiloxane, 0.01-1 part of reaction inhibitor, 0.01-1 part of crosslinking catalyst, and 2-10 parts of hydrogen-containing silicone oil. 5-30 parts of heat-expandable microspheres, 5-30 parts of ultrafine sodium bicarbonate powder. The preparation process of the invention is simple. The hollow heat-expandable microspheres and ultrafine sodium bicarbonate powder are blended with the components of silica gel according to the premixing ratio, so that they are evenly dispersed in the silica gel colloid, and the composite silica gel premix is obtained after curing. Then the premixed composite colloid is placed at a suitable temperature for heat treatment to obtain a low-density microporous silicone rubber composite material.

Description

A kind of low-density microporous silicone rubber composite material and preparation method thereof

technical field

The invention relates to a silicone rubber composite product and a preparation method thereof, in particular to the preparation of a low-density microporous silicone rubber composite material.

Background technique

Microporous polymer material is a composite material obtained by mixing, curing, molding and curing matrix resin (binder) and hollow microspheres. Silicone rubber composite materials combine the advantages of silicone rubber materials such as excellent high and low temperature resistance, non-toxicity, excellent chemical stability, excellent electrical insulation, light aging resistance and physiological inertness, and also have the low density and quality of microporous materials. Lightweight, good damping and high resilience. Because of its unique structure and excellent performance, it has been widely used in chemical industry, automobile, electrical and electronic, machinery, medicine, aerospace and other fields.

At present, hollow microspheres for the preparation of microporous silicone rubber composites mainly include borate hollow glass microspheres, hollow glass microspheres, phenolic hollow microspheres, zirconia hollow microspheres, carbon hollow microspheres, ceramic hollow microspheres, thermoplastic Hollow microspheres, silica hollow microspheres, etc. According to the structure of the shell of hollow microspheres, hollow microspheres can be roughly divided into hard microspheres and flexible microspheres. In prior art and reported literature, the preparation of microporous composite material can adopt one or two kinds of microsphere composite (LiuQ, Journal of Materials Science, 2015,50 (11): 3976-3983), also has patent report to be Hollow microspheres are used in conjunction with chemical foaming agents (Zhang Yanmin. Application research of thermally expandable microspheres in polyethylene foaming, master's thesis of Shanghai Jiao Tong University, 2011). If only hard microspheres are used for filling, the hard microspheres are easy to break, which will greatly reduce the flexibility of the silicone rubber composite material; the single use of flexible hollow microspheres will reduce the strength of the silicone rubber composite material, and the use of organic foaming agents will reduce the strength of the silicone rubber composite material. Bubbles, and its decomposition products do not meet environmental protection requirements. All of the above limit the application of microporous silicone rubber composites. In addition, due to the contradiction between foaming and silicone rubber curing, it is difficult to control the pore size, especially it is difficult to obtain a silicone rubber product with low density and uniform and fine pores.

Contents of the invention

The purpose of the present invention is to provide an environmentally friendly micro-aperture low-density silicone rubber composite material and a preparation method under the premise of ensuring the preparation process and the final product are environmentally friendly and non-toxic. The silicone rubber composite material adopts the combination of inorganic salt decomposition and hollow microsphere filling, and at the same time, by controlling the particle size of the inorganic salt and hollow microspheres, the internal pore diameter of the finally obtained silicone rubber composite material is less than 20 microns. The more significant advantages of this method are that the prepared silicone rubber composite material is environmentally friendly, non-toxic, low-density and simple in process.

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

A low-density microporous silicon rubber composite material, said low-density microporous silicon rubber composite material is composed of the following components by weight percentage:

The reaction inhibitor is ethynyl cyclohexanol; the cross-linking catalyst is a platinum catalyst; the particle size range of the ultrafine sodium bicarbonate is 1 to 10 microns; the diameter of the thermally expandable hollow microspheres is 6 ~9 microns.

Furthermore, the platinum catalyst described in the present invention is mainly composed of chloroplatinic acid and its complexes such as platinum-vinylsiloxane complex catalysts and the like.

Further, the hydrogen-containing silicone oil of the present invention has an active hydrogen mass fraction of 0.18% and a viscosity of 1000mpa.s.

Further, the vinyl polysiloxane described in the present invention is a vinyl polysiloxane containing two or more vinyl groups.

Furthermore, the vinyl polysiloxane described in the present invention is a vinyl polysiloxane reinforced with fumed silica. Utilizing fumed silica to reinforce vinyl polysiloxane is a technology well known to those skilled in the art. In the present invention, 0.3 parts of white carbon black is added to 1 mass part of vinyl polysiloxane, which is kneaded by a kneader at high intensity. A reinforced vinyl polysiloxane is obtained.

Preferably, the low-density microporous silicone rubber composite material of the present invention is recommended to be composed of the following components by weight percentage:

The present invention also provides a method for preparing the low-density microporous silicone rubber composite material:

(1) Weigh each component according to the proportion, add a crosslinking catalyst into the vinyl polysiloxane and knead evenly with a kneader; add a reaction inhibitor into the hydrogen-containing silicone oil, and stir evenly with a mixer;

(2) Blending the above-mentioned pretreated components using mechanical means to disperse the components uniformly to obtain a premix, which is subjected to vacuum degassing treatment, then poured into a mold, and then It is completely cured at 45-70° C., and then kept at 90-160° C. for 1-2 hours to obtain the silicone rubber composite material.

Beneficial effects of the present invention: 1: The preparation process of the method is simple, requires less equipment, has strong operability, and is easy for industrial production. 2: The silicone rubber composite foam material prepared by this method is environmentally friendly, non-toxic, and has low density, and the internal pores are decomposed by inorganic foaming agents and filled with hollow microspheres, that is, they contain both open-cell and closed-cell structures, and the pores are uniform. Fine and dense, the lowest density reaches 0.4g/cm ³ .

Description of drawings

Fig. 1 is the sectional view of embodiment 2 products.

detailed description

The present invention will be further described below in conjunction with specific examples, but the protection scope of the present invention is not limited thereto.

In the following examples and comparative examples, the raw material vinyl polysiloxane is a vinyl polysiloxane containing two or more vinyl groups and reinforced with fumed silica, which is commercially available in Dongguan City Liangzhan Silicone Technology Co., Ltd.; the cross-linking catalysts used are all platinum catalysts, which are commercially available. The catalyst is a complex with platinum catalysts, and its platinum loading is 5000ppm; the viscosity of the hydrogen-containing silicone oil used is 1000mpas, and the mass of active hydrogen The fraction is 0.18%, purchased from Dongguan Liangzhan Silicone Technology Co., Ltd.; the particle size distribution of the ultrafine sodium bicarbonate powder used is 1-10 μm, which is commercially available and obtained through a shaped ball mill; the brand name of the thermally expandable microspheres used is Expancel461DU20, produced by AkzoNobel, Sweden;

Comparative example 1

Take 100 parts by mass of vinyl polysiloxane, add 0.2 parts of platinum catalyst in advance; 10 parts by mass of hydrogen-containing silicone oil, add 0.2 parts of reaction inhibitor in advance. Then add the two components into the reaction container in turn, and then use mechanical mixing for 20 minutes to obtain the mixture; then use a three-roll mill to grind the mixed material to obtain a uniformly mixed material, and at the same time remove the air bubbles in the mixed colloid. In order to ensure that the air bubbles Completely exclude, use the vacuum box again for further exhaust treatment. Pour the blended rubber into the designed mold, and then put the mold with the rubber into a vacuum drying oven at a temperature of 60°C, and cure it for 1 hour to obtain an uncomposited silicone rubber as a comparison sample.

Example 1

Get 100 parts by mass of vinyl polysiloxane, add 0.2 parts of platinum catalyst in advance; 10 parts by mass of hydrogen-containing silicone oil, add 0.2 parts of reaction inhibitor in advance, 5 parts by mass of sodium bicarbonate powder, 5 parts by mass of thermally expandable microspheres, The above components are dispersed by mechanical stirring to obtain a premix, and then the premix is further blended by using a three-roll mill to disperse the components uniformly to obtain a premix. Then use a three-roll mill with a roll distance of 0.1mm to grind the mixed material to obtain a uniformly mixed material, and at the same time remove the air bubbles in the mixed colloid. In order to ensure the complete removal of the air bubbles, use a vacuum box again to further exhaust it. . The blended rubber was poured into the designed mold, and cured at a temperature of 60° C. for 1 hour to obtain a cured gel. Then the temperature was raised to 140°C, and the heat preservation treatment was carried out for 2 hours, so that the sodium bicarbonate powder filled in the colloid was decomposed and gasified, and at the same time, the liquid hydrocarbon inside the heat-expandable microspheres was gasified to obtain the final silicone rubber composite material.

Example 2

Take 100 parts by mass of vinyl polysiloxane, add 0.1 part of platinum catalyst in advance; 10 parts by mass of hydrogen-containing silicone oil, add in advance 0.1 part of reaction inhibitor, 10 parts by mass of sodium bicarbonate powder, and 10 parts of thermally expandable microspheres. The above components are dispersed by mechanical stirring to obtain a premix, and then the premix is further blended by using a three-roll mill to disperse the components uniformly to obtain a premix. Then use a three-roll mill with a roll distance of 0.1mm to grind the mixed material to obtain a uniformly mixed material, and at the same time remove the air bubbles in the mixed colloid. In order to ensure the complete removal of the air bubbles, use a vacuum box again to further exhaust it. . The blended rubber was poured into the designed mold, and cured at a temperature of 70°C for 1 hour to obtain a cured gel. Then the temperature was raised to 140°C, and the heat preservation treatment was carried out for 2 hours, so that the sodium bicarbonate powder filled in the colloid was decomposed and gasified, and at the same time, the liquid hydrocarbon inside the heat-expandable microspheres was gasified to obtain the final silicone rubber composite material.

Example 3

Take 100 parts by mass of vinyl polysiloxane, add 0.2 parts of platinum catalyst in advance; The above components are dispersed by mechanical stirring to obtain a premix, and then the premix is further blended by using a three-roller mill to uniformly disperse each component to obtain a premix. Then use a three-roll mill with a roll distance of 0.1mm to grind the mixed material to obtain a uniformly mixed material, and at the same time remove the air bubbles in the mixed colloid. In order to ensure the complete removal of the air bubbles, use a vacuum box again to further exhaust it. . The blended rubber was poured into the designed mold, and cured at a temperature of 70°C for 1 hour to obtain a cured gel. Then the temperature was raised to 140°C, and the heat preservation treatment was carried out for 2 hours, so that the sodium bicarbonate powder filled in the colloid was decomposed and gasified, and at the same time, the liquid hydrocarbon inside the heat-expandable microspheres was gasified to obtain the final silicone rubber composite material.

Example 4

Take 100 parts by mass of vinyl polysiloxane, add 2 parts of platinum catalyst in advance; The above components are dispersed by mechanical stirring to obtain a premix, and then the premix is further blended with a three-roll mill to make the components uniformly dispersed to obtain a premix. Then use a three-roll mill with a roll distance of 0.1mm to grind the mixed material to obtain a uniformly mixed material, and at the same time remove the air bubbles in the mixed colloid. In order to ensure the complete removal of the air bubbles, use a vacuum box again to further exhaust it. . The blended rubber was poured into the designed mold, and cured at a temperature of 45° C. for 1 hour to obtain a cured gel. Then the temperature is raised to 160°C, and the heat preservation treatment is carried out for 1 hour, so that the sodium bicarbonate powder filled in the colloid is decomposed and gasified, and at the same time, the liquid hydrocarbon inside the heat-expandable microspheres is gasified to obtain the final silicone rubber composite material.

Example 5

Take 100 parts by mass of vinyl polysiloxane, add 0.2 parts of platinum catalyst in advance; The above components are dispersed by mechanical stirring to obtain a premix, and then the premix is further blended by using a three-roller mill to uniformly disperse each component to obtain a premix. Then use a three-roll mill with a roll distance of 0.1mm to grind the mixed material to obtain a uniformly mixed material, and at the same time remove the air bubbles in the mixed colloid. In order to ensure the complete removal of the air bubbles, use a vacuum box again to further exhaust it. . The blended rubber was poured into the designed mold, and cured at a temperature of 60° C. for 1 hour to obtain a cured gel. Then raise the temperature to 90°C and heat-preserve for 2 hours to decompose and gasify the sodium bicarbonate powder filled in the colloid, and at the same time gasify the liquid hydrocarbon inside the heat-expandable microspheres to obtain the final silicone rubber composite material.

Example 6

Take 100 parts by mass of vinyl polysiloxane, add 0.5 parts of platinum catalyst in advance; 10 parts by mass of hydrogen-containing silicone oil, add in advance 0.5 parts of reaction inhibitor, 30 parts by mass of sodium bicarbonate powder, and 30 parts by mass of thermally expandable microspheres. The above-mentioned components are dispersed by mechanical stirring to obtain a premix, and then the premix is further blended by using a three-roller mill, so that each component is uniformly dispersed to obtain a premix. Then use a three-roll mill with a roll distance of 0.1mm to grind the mixed material to obtain a uniformly mixed material, and at the same time remove the air bubbles in the mixed colloid. In order to ensure the complete removal of the air bubbles, use a vacuum box again to further exhaust it. . The blended rubber was poured into the designed mold, and cured at a temperature of 60° C. for 1 hour to obtain a cured gel. Then raise the temperature to 90°C and heat-preserve for 2 hours to decompose and gasify the sodium bicarbonate powder filled in the colloid, and at the same time gasify the liquid hydrocarbon inside the heat-expandable microspheres to obtain the final silicone rubber composite material.

Example 7

Get 100 parts by mass of vinyl polysiloxane, add 0.2 parts of platinum catalyst in advance; 2 parts by mass of hydrogen-containing silicone oil, add 0.2 parts of reaction inhibitor in advance, 5 parts by mass of sodium bicarbonate powder, 5 parts by mass of thermally expandable microspheres, The above components are dispersed by mechanical stirring to obtain a premix, and then the premix is further blended by using a three-roll mill to disperse the components uniformly to obtain a premix. Then use a three-roll mill with a roll distance of 0.1mm to grind the mixed material to obtain a uniformly mixed material, and at the same time remove the air bubbles in the mixed colloid. In order to ensure the complete removal of the air bubbles, use a vacuum box again to further exhaust it. . The blended rubber was poured into the designed mold, and cured at a temperature of 60° C. for 1 hour to obtain a cured gel. Then the temperature is raised to 160°C, and the heat preservation treatment is carried out for 1 hour, so that the sodium bicarbonate powder filled in the colloid is decomposed and gasified, and at the same time, the liquid hydrocarbon inside the heat-expandable microspheres is gasified to obtain the final silicone rubber composite material.

Example 8

Get 100 parts by mass of vinyl polysiloxane, add 0.2 parts of platinum catalyst in advance; 7 parts by mass of hydrogen-containing silicone oil, add 0.2 parts of reaction inhibitor in advance, 5 parts by mass of sodium bicarbonate powder, 5 parts by mass of thermally expandable microspheres, The above components are dispersed by mechanical stirring to obtain a premix, and then the premix is further blended by using a three-roll mill to disperse the components uniformly to obtain a premix. Then use a three-roll mill with a roll distance of 0.1mm to grind the mixed material to obtain a uniformly mixed material, and at the same time remove the air bubbles in the mixed colloid. In order to ensure the complete removal of the air bubbles, use a vacuum box again to further exhaust it. . The blended rubber was poured into the designed mold, and cured at a temperature of 60° C. for 1 hour to obtain a cured gel. Then the temperature is raised to 160°C, and the heat preservation treatment is carried out for 1 hour, so that the sodium bicarbonate powder filled in the colloid is decomposed and gasified, and at the same time, the liquid hydrocarbon inside the heat-expandable microspheres is gasified to obtain the final silicone rubber composite material.

Comparative example and the test result of each embodiment silicone rubber composite material are shown in the table below:

After experiments and tests, the prepared low-density microporous silicone rubber composite material has internal heat-expandable hollow microspheres and sodium bicarbonate particles dispersed evenly in the silica gel colloid, and the pore diameters of the cells formed by the decomposition of sodium bicarbonate are all within 15 microns. Fine and uniform, the pore size of thermal expansion microspheres is less than 20 microns, as shown in Figure 1.

It should be pointed out that the embodiments of the present invention are only for illustrating the technical concepts and features of the present invention, and its purpose is to enable those familiar with this technology to understand the innovations and contents of the present invention and implement them accordingly. Equivalent changes or modifications based on the structures, features and principles described in the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims (7)

1. A low-density microporous silicon rubber composite material, characterized in that said low-density microporous silicon rubber composite material is composed of the following components by weight percentage: The reaction inhibitor is ethynyl cyclohexanol; the cross-linking catalyst is a platinum catalyst; the particle size range of the ultrafine sodium bicarbonate is 1 to 10 microns; the diameter of the thermally expandable hollow microspheres is 6 ~9 microns. 2. The microporous silicone rubber composite material according to claim 1, characterized in that: said vinyl polysiloxane is vinyl polysiloxane containing two or more vinyl groups. 3. The microporous silicone rubber composite material according to claim 2, characterized in that: said vinyl polysiloxane is vinyl polysiloxane reinforced with fumed silica. 4. microporous silicone rubber composite material as claimed in claim 3, is characterized in that: the vinyl polysiloxane of described fumed silica reinforcement is to add 0.3 part in the vinyl polysiloxane of 1 mass part Silica, a reinforced vinyl polysiloxane obtained by high-intensity kneading in a kneader. 5. The microporous silicone rubber composite material according to claim 2, characterized in that: the hydrogen-containing silicone oil has an active hydrogen mass fraction of 0.18% and a viscosity of 1000mpa.s. 6. The low-density microporous silicone rubber composite material according to any one of claims 1 to 5, characterized in that the low-density microporous silicone rubber composite material is composed of the following components by weight percentage: 7. the preparation method of low-density microporous silicone rubber composite material as claimed in claim 1, is characterized in that described method is: (1) Weigh each component according to the proportion, add a crosslinking catalyst into the vinyl polysiloxane and knead evenly with a kneader; add a reaction inhibitor into the hydrogen-containing silicone oil, and stir evenly with a mixer; (2) Blending the above-mentioned pretreated components using mechanical means to disperse the components uniformly to obtain a premix, which is subjected to vacuum degassing treatment, then poured into a mold, and then It is completely cured at 45-70° C., and then kept at 90-160° C. for 1-2 hours to obtain the silicone rubber composite material.