WO2018036431A1

WO2018036431A1 - Modified nanocomposite silicone rubber seal ring and preparation thereof

Info

Publication number: WO2018036431A1
Application number: PCT/CN2017/098074
Authority: WO
Inventors: 段曦东; 李晓丰; 毛志浩
Original assignee: 广东纳路纳米科技有限公司
Priority date: 2016-08-22
Filing date: 2017-08-18
Publication date: 2018-03-01
Also published as: CN106317901A; CN106317901B

Abstract

Provided is a modified nanocomposite silicone rubber seal ring, comprising: raw rubber mixing rubber material and vulcanizing agent with weight ratio of 100: 0.5 to 10. The raw rubber mixing rubber material comprises the following parts by weight: 70 to 100 parts of methyl vinyl silicone rubber, 1 to 20 parts of plasticizer, 0.01 to 10 parts of modified nano additive, 10 to 50 parts of reinforcing filler and 0.5 to 5 parts of coupling agent. The modified nano additive is one of modified white graphene, modified graphene and graphene oxide. The composite silicone rubber seal ring is added with a small amount of nano-modified particles, which is helpful in increasing sealing performance and mechanical strength, while not affecting other properties. The modified nanocomposite silicone rubber seal ring effectively solves the problems that water vapor and gas permeability of the silicone seal ring is degraded and mechanical properties thereof is reduced due to the aging in the course of a long time using, thereby greatly extending the service life of the sealing material.

Description

[Name of invention established by ISA according to Rule 37.2] Modified nanocomposite silicone sealing ring and preparation thereof

Technical field

The invention relates to the technical field of sealing rings, in particular to a modified nano composite silicone sealing ring and a preparation thereof.

Background technique

As a key connector between the sealing member and the component, the silicone sealing ring is widely used in aerospace, medical, automotive, household appliances and the like because of its excellent heat resistance, low temperature elasticity and oxidation resistance. Compared with sealing rings such as polysulfide rubber and fluororubber, the silicone sealing ring itself has high water vapor and gas permeability, which makes the sealing performance lower, and decays aging over time during use, silicone rubber Gradually losing the elasticity, the mechanical properties of the silicone sealing ring are reduced, and the reduction of the airtightness is further amplified, resulting in undesirable phenomena such as air leakage, water leakage, oil leakage, etc., which affects its application as a sealing material.

Summary of the invention

In view of this, it is necessary to provide a simple and effective modified nanocomposite silicone sealing ring and its preparation for the above problems.

To achieve the above object, the present invention adopts the following technical solutions:

The modified nano composite silicone sealing ring of the invention comprises: a raw rubber mixing compound and a vulcanizing agent in a weight ratio of 100: 0.5-10;

The raw rubber compounding compound comprises: 70-100 parts of methyl vinyl silicone rubber, 1-20 parts of plasticizer, 0.01-10 parts of modified nano additive, 10 to 50 parts of reinforcing filler, 0.5 to 5 parts of coupling agent;

The modified nano additive is one of modified white graphene, modified graphene, and graphene oxide.

Preferably, the raw rubber compounding compound comprises: 80-100 parts of methyl vinyl silicone rubber, 1-15 parts of plasticizer, 0.05-5 parts of nano-modifying additive, 15-40 parts by weight. Reinforcing filler, 0.5~3 parts coupling agent.

Preferably, the methyl vinyl silicone rubber has a vinyl mole percentage of 0.12%, 0.25% or 0.56%.

More preferably, the methyl vinyl silicone rubber has a vinyl mole percentage of 0.25% in consideration of the plasticity and mechanical properties of the raw rubber.

Preferably, the modified white graphene is treated with 5 to 10 layers of white graphene via a long-chain Lewis base, a long-chain Lewis acid, a sulfonate, a quaternary amine or a nonionic surfactant to increase white graphite. The affinity of the alkene to the substrate; the modified white graphene is 5 to 10 layers of graphene treated with polyvinylpyrrolidone (PVP) or sodium dodecylbenzenesulfonate (SDBS) surfactant to increase the graphene pair The affinity of the matrix.

Further preferably, the long-chain Lewis base is oleylamine or the like; the long-chain Lewis acid is long-chain borane or the like; the sulfonate is sodium dodecylbenzenesulfonate or the like; and the quaternary amine is bromine The cetylpyridine or the like; the nonionic surfactant is a polyethylene oxide alkyl alcohol amide or the like.

Preferably, the plasticizer is selected from the group consisting of dimethicone, hydroxypolydimethylsiloxane, and vinyltrimethoxysilane;

The reinforcing filler is one of fumed silica, silicon micropowder, and carbon black;

The coupling agent is one of a silane coupling agent KH-550, a silane coupling agent KH-570, and n-butyl titanate;

The vulcanizing agent is one of benzoyl peroxide, di-tert-butyl peroxide, and dicumyl peroxide.

The preparation method of the modified nano composite silicone sealing ring of the invention comprises:

Step 1) selecting one of modified white graphene, modified graphene, and graphene oxide as nano Additive; modification method: 5-10 layers of white graphene are selected by soaking with long-chain Lewis base, long-chain Lewis acid, sulfonate, quaternary amine or non-ionic surfactant in a concentration of 0.1% by mass. 24 hours, after centrifugation, vacuum drying to obtain modified white graphene additive; 5 to 10 layers of graphene dispersed in a concentration of 0.3mg / ml polyvinylpyrrolidone or sodium dodecylbenzenesulfonate aqueous solution for 10 hours The modified graphene additive is obtained after centrifugation and vacuum drying;

Step 2) Raw rubber mixing: According to the parts by weight, the methyl vinyl silicone rubber, the plasticizer, the coupling agent, the modified nano additive and the reinforcing filler are respectively mixed, and after being mixed for several times by the internal mixer, the double is used. Extrusion by a screw extruder to obtain a raw rubber compound;

Step 3) Vulcanization molding: Weigh the raw rubber compound and vulcanizing agent in step 2) according to the proportion, mix and disperse uniformly in the internal mixer, and then put it into the mold and vulcanize it by hot press molding to obtain modification. Nano composite silicone sealing ring.

Preferably, the raw rubber mixing process in the step 2) is that the components are kneaded in an internal mixer at a temperature of 40 to 120 ° C for 5 to 60 minutes, and then subjected to a twin screw extruder at a temperature of 80. Extrusion at -250 ° C to obtain a raw rubber compound.

Preferably, in the vulcanization molding process of the hot press forming machine in the step 3), the control temperature is 100 to 250 ° C, the pressure is 1 to 20 Mpa, and the vulcanization molding time is 10 to 90 min.

Compared with the prior art, the beneficial effects of the present invention are:

Silica gel seals exist in high temperature and harsh environments for a long time, and the side chain methyl groups are easily oxidized to form crosslinks, which leads to hardening of the materials; the use of surfactant-treated white graphene, graphene and oxidation of the surface containing more active groups Graphene can achieve good wettability with the matrix when added in a small amount, increase the toughness to enhance the effect, and improve the mechanical strength of the silicone sealing ring.

The invention selects a material obtained by modifying 5 to 10 layers of white graphene, graphene or graphene oxide nano powder, wherein the atomic layer can effectively isolate gas atom molecules, and the gas molecules only pass through the silicone rubber. When the modified white graphene, modified graphene, and modified graphene oxide atomic layer are less than ten layers, the layer arrangement Compact, uniform, and a large number of barrier sheets, the gas bypasses the silicone rubber, the path becomes longer, and a small amount of addition can well block the passage of gas, increasing the airtightness of the nanocomposite silicone sealing ring.

The invention improves the water vapor, gas permeability deterioration and mechanical property degradation caused by aging of the silicone sealing ring during long-term use, greatly prolongs the service life of the sealing material, and has high application value.

detailed description

In order to make the objects, the technical solutions and the advantages of the present invention more clearly, the technical solutions of the present invention will be further clearly and completely described below in conjunction with the embodiments of the present invention. It should be noted that the described embodiments are only a part of the embodiments of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Example 1

Step 1) Modification of the nano additive: 5 to 10 layers of white graphene are selected by soaking for 12 hours with 0.1% aqueous oleylamine solution, and the modified white graphene additive is obtained by centrifugation and vacuum drying;

Step 2) Raw rubber mixing: 100 parts by weight of methyl vinyl silicone rubber having a molar percentage of 0.25%, 15 parts of hydroxyl terminated polydimethylsiloxane, and 3 parts of a silane coupling agent are weighed by weight. KH-570, 0.1 parts of modified white graphene additive prepared in step 1) and 30 parts of carbon black, which are sequentially added to an internal mixer for kneading, the mixing temperature is 90 ° C, the mixing time is 50 min; The extruder is extruded at a temperature of 120 ° C to obtain a raw rubber compound;

Step 3) vulcanization molding: 100 parts by weight of the raw rubber mixing compound obtained in the step 2) and 3 parts of di-tert-butyl peroxide are respectively weighed, mixed and dispersed at room temperature by an internal mixer, and then placed in a special system. The modified nanocomposite silicone sealing ring was obtained by hot pressing vulcanization in a mold at a temperature of 150 ° C, a pressure of 18 MPa, and a time of 40 min.

Example 2

Step 2) Raw rubber mixing: 100 parts by weight of methyl vinyl silicone rubber having a molar percentage of 0.25%, 8 parts of hydroxyl terminated polydimethylsiloxane, and 1 part of a silane coupling agent are weighed in parts by weight. KH-570, 0.5 parts of modified white graphene additive prepared in step 1) and 20 parts of carbon black, which are sequentially added to an internal mixer for kneading, the mixing temperature is 60 ° C, the mixing time is 20 min; The screw extruder is extruded at a temperature of 180 ° C to obtain a raw rubber compound;

Step 3) vulcanization molding: 100 parts by weight of the raw rubber mixing compound obtained in the step 2) and 1.5 parts of di-tert-butyl peroxide are respectively weighed, mixed and dispersed at room temperature by an internal mixer, and then placed in a special system. The modified nanocomposite silicone sealing ring was obtained by hot pressing vulcanization in a mold at a temperature of 180 ° C, a pressure of 12 MPa, and a time of 20 min.

Example 3

Step 1) modification of the nano additive: using 5 to 10 layers of graphene dispersed in a concentration of 0.3 mg / ml polyvinylpyrrolidone aqueous solution for 10 hours, after centrifugation, vacuum drying to obtain a modified graphene additive;

Step 2) Raw rubber mixing: 100 parts by weight of methyl vinyl silicone rubber having a molar percentage of 0.25%, 15 parts of hydroxyl terminated polydimethylsiloxane, and 3 parts of a silane coupling agent are weighed by weight. KH-570, 0.1 parts of modified graphene additive prepared in step 1) and 30 parts of carbon black, which are sequentially added to an internal mixer for kneading, the mixing temperature is 90 ° C, the mixing time is 50 min; The machine is extruded at a temperature of 120 ° C to obtain a raw rubber compound;

Example 4

Step 2) Raw rubber mixing: 100 parts by weight of methyl vinyl silicone rubber having a molar percentage of 0.25%, 8 parts of hydroxyl terminated polydimethylsiloxane, and 1 part of a silane coupling agent are weighed in parts by weight. KH-570, 0.6 parts of modified graphene additive prepared in step 1) and 20 parts of carbon black, which are sequentially added to an internal mixer for kneading, the mixing temperature is 60 ° C, the mixing time is 20 min; Extrusion at a temperature of 180 ° C to obtain a raw rubber compound;

Step 3) vulcanization molding: 100 parts by weight of the raw rubber mixing compound prepared in the step 2) and 1.5 parts of di-tert-butyl peroxide are respectively weighed, mixed and dispersed at room temperature by an internal mixer, and then placed in a special system. The modified nanocomposite silicone sealing ring was obtained by hot pressing vulcanization in a mold at a temperature of 180 ° C, a pressure of 12 MPa, and a time of 20 min.

Example 5

Step 1) Raw rubber mixing: 100 parts by weight of methyl vinyl silicone rubber having a molar percentage of 0.25%, 15 parts of hydroxyl terminated polydimethylsiloxane, and 3 parts of a silane coupling agent are weighed by weight. KH-570, 0.1 part of graphene oxide additive and 30 parts of carbon black, which are sequentially added to the mixer for mixing, the mixing temperature is 90 ° C, the mixing time is 50 min, and the temperature of the twin-screw extruder is 120 ° C. Extrusion to obtain a raw rubber compound;

Step 2) Silica gel vulcanization molding: 100 parts by weight of the raw rubber mixing compound prepared in the step 2) and 3 parts of di-tert-butyl peroxide are separately weighed, mixed and dispersed at room temperature by an internal mixer, and then placed. The modified nanocomposite silicone sealing ring was obtained by hot pressing vulcanization at a temperature of 150 ° C, a pressure of 18 MPa and a time of 40 min in a special mold.

Example 6

Step 1) Raw rubber mixing: 100 parts by weight of methyl vinyl silicone rubber having a molar percentage of 0.25%, 8 parts of hydroxyl terminated polydimethylsiloxane, and 1 part of a silane coupling agent are weighed by weight. KH-570, 0.4 parts of graphene oxide additive and 20 parts of carbon black, which are sequentially added to the mixer for mixing, the mixing temperature is 60 ° C, the mixing time is 20 min, and the temperature of the twin-screw extruder is 180 ° C. Extrusion to obtain a raw rubber compound;

Comparative Example 1

Step 1) Raw rubber mixing: 100 parts of methyl vinyl silicone rubber having a vinyl mole fraction of 0.25%, 15 parts of hydroxyl terminated polydimethylsiloxane, and 3 parts of a silane coupling agent are weighed by weight. KH-570, and 30 parts of fumed silica, which are sequentially added to an internal mixer for kneading, the kneading temperature is 90 ° C, the kneading time is 50 min; and the twin-screw extruder is extruded at a temperature of 120 ° C. Obtaining the compound after mixing;

Step 2) vulcanization molding: 100 parts by weight of the compounded compound obtained in the step 2) and 3 parts of di-tert-butyl peroxide are respectively weighed, mixed and dispersed at room temperature by an internal mixer, and then placed in a special mold. The medium-temperature thermoforming machine is hot-pressed and vulcanized at a temperature of 150 ° C, a pressure of 18 MPa, and a time of 40 min to obtain a composite silicone sealing ring.

Comparative Example 2

Step 1) Raw rubber mixing: 100 parts by weight of methyl vinyl silicone rubber having a molar percentage of 0.25%, 8 parts of hydroxyl terminated polydimethylsiloxane, and 1 part of a silane coupling agent are weighed by weight. KH-570, and 20 parts of carbon black, which are sequentially added to the mixer for mixing, the mixing temperature is 60 ° C, the mixing time is 20 min; and the twin-screw extruder is extruded at 180 ° C to obtain a mixture. Refining rubber compound;

Step 2) vulcanization molding: 100 parts by weight of the compounded mixture obtained in step 2) And 1.5 parts of di-tert-butyl peroxide, mixed and dispersed uniformly at room temperature by an internal mixer, and then placed in a special mold to obtain a modified nanocomposite by hot pressing vulcanization at a temperature of 180 ° C, a pressure of 12 MPa, and a time of 20 min. Silicone sealing ring.

Table 1 shows the performance parameters of each example:

Table 1 The properties of the products obtained in the above various examples

It can be seen from the above table that the modified nano-composite silicone sealing ring of the invention can significantly reduce the permeability of the composite silicone sealing ring to gas and water vapor and effectively improve the mechanical strength, and greatly prolong the service life of the sealing material, which is high. Value.

The above-mentioned embodiments are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims

A modified nano-composite silicone sealing ring comprises a raw rubber mixing compound and a vulcanizing agent in a weight ratio of 100:0.5-10;

The raw rubber compounding compound comprises: 70-100 parts of methyl vinyl silicone rubber, 1-20 parts of plasticizer, 0.01-10 parts of modified nano additive, 10 to 50 parts of reinforcing filler, 0.5 to 5 parts of coupling agent;

The modified nano additive is one of modified white graphene, modified graphene, and graphene oxide.
The modified nanocomposite silicone sealing ring according to claim 1, wherein the raw rubber compounding compound comprises 80 parts by weight to 100 parts by weight of methyl vinyl silicone rubber and 1 to 15 parts plasticized. Agent, 0.05-5 parts nano modification additive, 15-40 parts reinforcing filler, 0.5-3 parts coupling agent.
The modified nanocomposite silicone sealing ring according to claim 1 or 2, wherein the methyl vinyl silicone rubber has a vinyl mole percentage of 0.12%, 0.25% or 0.56%.
The composite silicone sealing ring prepared by the nano-modified silicone rubber according to claim 3, wherein the methyl vinyl silicone rubber has a vinyl mole percentage of 0.25%.
The modified nanocomposite silica gel sealing ring according to claim 1 or 2, wherein the modified white graphene is 5 to 10 layers of white graphene via a long-chain Lewis base, a long-chain Lewis acid, and a sulfonate. Treated with a quaternary amine or a nonionic surfactant; the modified white graphene is 5 to 10 layers of graphene treated with polyvinylpyrrolidone or sodium dodecylbenzenesulfonate surfactant.
The modified nanocomposite silica gel sealing ring according to claim 5, wherein the long-chain Lewis base is oleylamine; the long-chain Lewis acid is long-chain borane; and the sulfonate is dodecane Sodium benzenesulfonate; the quaternary amine is cetylpyridinium bromide; and the nonionic surfactant is a polyethylene oxide alkyl alcohol amide.
The modified nanocomposite silicone sealing ring according to claim 1 or 2, characterized in that The plasticizer is selected from the group consisting of dimethicone, hydroxypolydimethylsiloxane, and vinyltrimethoxysilane;

The reinforcing filler is one of fumed silica, silicon micropowder, and carbon black;

The coupling agent is one of a silane coupling agent KH-550, a silane coupling agent KH-570, and n-butyl titanate;

The vulcanizing agent is one of benzoyl peroxide, di-tert-butyl peroxide, and dicumyl peroxide.
A method for preparing a modified nanocomposite silicone sealing ring according to claim 1 or 2, comprising:

Step 1) Select one of modified white graphene, modified graphene, and graphene oxide as a nano additive; modification method: select 5-10 layers of white graphene with a long chain of 0.1% by mass concentration Lewis base, long-chain Lewis acid, sulfonate, quaternary amine or non-ionic surfactant aqueous solution is immersed for 24 hours, centrifuged, vacuum dried to obtain modified white graphene additive; dispersed with 5-10 layers of graphene After being ultrasonicated for 10 hours in an aqueous solution of polyvinylpyrrolidone or sodium dodecylbenzenesulfonate at a concentration of 0.3 mg/ml, the modified graphene additive is obtained by centrifugation and vacuum drying;

Step 2) Raw rubber mixing: According to the parts by weight, the methyl vinyl silicone rubber, the plasticizer, the coupling agent, the modified nano additive and the reinforcing filler are respectively mixed, and after being mixed for several times by the internal mixer, the double is used. Extrusion by a screw extruder to obtain a raw rubber compound;

Step 3) Vulcanization molding: Weigh the raw rubber compound and vulcanizing agent in step 2) according to the proportion, mix and disperse uniformly in the internal mixer, and then put it into the mold and vulcanize it by hot press molding to obtain modification. Nano composite silicone sealing ring.
The method for preparing a modified nanocomposite silica gel sealing ring according to claim 8, wherein the raw rubber mixing process in the step 2) is that the components are in an internal mixer at a temperature of 40 to 120 ° C, The mixture is kneaded at a time of 5 to 60 minutes, and then extruded at a temperature of 80 to 250 ° C by a twin-screw extruder to obtain a raw rubber mixture. material.
The method for preparing a modified nanocomposite silicone sealing ring according to claim 8, wherein in the step of vulcanizing, the temperature of the hot press forming machine is controlled at a temperature of 100 to 250 ° C, a pressure of 1 to 20 MPa, and vulcanization. The molding time is 10 to 90 minutes.