Elastic silicon resin material with shape memory function and preparation method of sleeve of elastic silicon resin material

Abstract

The invention provides an elastic silicon resin material with a shape memory function and a preparation method of a sleeve of the elastic silicon resin material, and relates to the technical field of silicon rubber materials. The elastic silicon resin material with the shape memory function comprises the following components: a solid silicon resin polymer containing a phenyl functional group, silicon rubber, a flame retardant, a catalyst and phenyl polyester silicon wax. The invention further provides a preparation method of the elastic silicon resin sleeve with the shape memory function, and the elastic silicon resin sleeve with the shape memory function has the advantages of being good in flame retardance, low in hardness, resistant to bending fatigue, resistant to high temperature and resistant to low-temperature harsh environments. The composite material can be applied to electric drive automobiles, electronic industry and other scenes in the aspects of bending fatigue and high and low temperature resistant insulation protection.

Description

Technical Field

[0001] The invention relates to the technical field of silicone rubber materials, and in particular to a method for preparing an elastic silicone resin material with shape memory function and a sleeve thereof. Background Art

[0002] Silicone resin is a thermosetting polysiloxane with a highly cross-linked structure. Due to its special structure, compared with other organic resins, it has excellent heat resistance, cold resistance, weather resistance, electrical insulation, hydrophobicity and anti-sticking demoulding properties. Therefore, it is widely used as high and low temperature resistant insulating paint, heat resistant coating, weather resistant coating, ablation resistant coating and high and low temperature resistant, electrical insulating molding materials. The research on solid phenyl silicone resin in the modification of thermoplastic resins focuses on improving the high temperature resistance of thermoplastic resins, improving mechanical properties, and enhancing the chemical resistance and electrical insulation of materials. Pure resins are rarely used in application scenarios that require resistance to bending fatigue. There are few reports on the application of solid phenyl silicone resin in heat-shrinkable shape memory materials.

[0003] Chinese patent CN 101157802 B discloses a silicone rubber material with memory function and its preparation method, wherein eucommia gum or fluororubber and thermoplastic resins such as PE, PP or EVA are mixed into the mixed silicone rubber, and the heat shrinkable silicone rubber belt, heat shrinkable tube or silicone special-shaped product is obtained by molding or extrusion, compression, stretching, blowing and cooling at 50-250°C. The tear strength of the product is 14-20N / mm, and the hardness is in the range of 65-75A. The tear strength of the product is not ideal.

[0004] Chinese patent CN 101993589 B discloses a silicone rubber heat shrinkable tube and its preparation method. Silicone rubber, including dimethyl silicone rubber (MQ), methyl vinyl silicone rubber (VMQ), methyl phenyl vinyl silicone rubber (PVMQ), is added with one or more thermoplastic resins including (phenyl silicone resin, phenylene silicone resin, methyl silicone resin, vinyl silicone resin, acrylic resin, ethylene vinyl acetate copolymer (EVA), ethylene ethyl acrylate copolymer (EEA), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE)) to prepare a silicone heat shrinkable tube. The silicone rubber heat shrinkable tube provided by the invention has good stability and high heat resistance and cold resistance, but its tear strength, bending fatigue resistance and other characteristics are insufficient.

[0005] However, existing studies have shown that: in silicone rubber / EVA composite materials, as the amount of EVA filling increases, the mechanical properties of the composite material increase, but its thermal stability decreases (Study on the blending modification of EVA on silicone rubber compound [J] Materials Guide, 2010.5(24): 415-424.); Other studies have found that as the amount of EVA added increases, the retention rate of the mechanical properties of silicone rubber after aging is significantly reduced, and the addition of EVA will greatly reduce the operating temperature of the silicone rubber blend (Study on the thermal oxidation aging properties of silicone rubber / EVA blends: II The role of antioxidants [J]. Elastomers, 1993, 3(2): 6.).

[0006] At present, silicone rubber heat shrink tubing has been widely used in power, motor, automobile, electronics, aviation and other industrial fields due to its excellent properties such as heat resistance and insulation. However, the performance of existing silicone rubber heat shrink tubing, especially the high temperature resistance and long-term use performance, bending fatigue resistance, flame retardant performance, etc., is still not ideal, and cannot meet the stringent requirements of complex electrical systems such as new energy vehicles. In order to obtain the shape memory function, the polyolefin thermoplastic resin added will actually reduce the use temperature and aging temperature of the silicone rubber blend (i.e. shorten the service life of the material), or in order to obtain better flame retardant performance, a large amount of additive inorganic fillers such as white carbon black, flame retardants such as antimony trioxide synergistic halogen flame retardant, magnesium hydroxide, aluminum hydroxide, etc. are usually added to improve the flame retardant performance of the silicone rubber mixture. However, too much inorganic flame retardant will cause the insulation withstand voltage performance, tear resistance, flexibility, bending fatigue resistance, etc. of the silicone rubber heat shrink tubing to decrease, as well as the key performances such as expansion and contraction to decrease significantly or even lose.

[0007] Based on this, the present invention provides an elastic silicone resin material with shape memory function and a preparation method thereof. By screening and optimizing its components, the final product not only has high tear strength and good flame retardancy, but also is resistant to bending fatigue, which makes up for the shortcomings of the prior art. Summary of the invention

[0008] In view of the above problems, the present invention provides an elastic silicone material with shape memory function, the main materials of which include a solid silicone polymer containing phenyl functional groups, addition vulcanized silicone rubber, composite flame retardant, two-component platinum catalyst, and phenyl polyester silicone wax. It not only has good flame retardancy, but also is resistant to bending fatigue, and can be applied to electric-driven vehicles, the electronics industry, and other scenarios in terms of bending fatigue and high and low temperature insulation protection.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0010] On the one hand, the present invention provides an elastic silicone material with shape memory function, comprising the following components: a solid silicone polymer containing a phenyl functional group, silicone rubber, a composite flame retardant, a catalyst and a phenyl polyester silicone wax.

[0011] Preferably, the elastic silicone resin material comprises the following components by weight: 95-110 parts of a solid silicone resin polymer containing a phenyl functional group, 75-125 parts of silicone rubber, 9-35 parts of a composite flame retardant, 0.4-1 parts of a catalyst, and 0.3-2.5 parts of a phenyl polyester silicone wax.

[0012] Further preferably, the elastic silicone resin material comprises the following components by weight: 98-100 parts of a solid silicone resin polymer containing a phenyl functional group, 78-120 parts of silicone rubber, 10-32 parts of a composite flame retardant, 0.5-0.8 parts of a catalyst, and 0.5-2 parts of a phenyl polyester silicone wax.

[0013] Preferably, the melting point of the solid silicone resin polymer containing phenyl functional groups is 70-90°C; further preferably, the melting point of the solid silicone resin polymer containing phenyl functional groups is 75-85°C.

[0014] Preferably, the silicone rubber is addition-vulcanized silicone rubber;

[0015] Preferably, the addition-vulcanized silicone rubber is added with A / B (0.4-0.5 / 0.6-0.7), and the addition vulcanization is performed at 195-205°C for 1.5-3h; further preferably, the addition-vulcanized silicone rubber is added with A / B (0.5 / 0.7), and the addition vulcanization is performed at 200°C for 2h;

[0016] Preferably, the hardness of the addition-vulcanized silicone rubber is 40A-50A, the tensile strength after two-stage vulcanization is ≥9MPa, the elongation at break is ≥800%, and the tear strength is ≥30N / mm.

[0017] Preferably, the composite flame retardant is a combination of a platinum flame retardant and aluminum hydroxide. Preferably, the mass ratio of the platinum flame retardant to the aluminum hydroxide flame retardant is 1:90-110, and more preferably, the mass ratio of the platinum flame retardant to the aluminum hydroxide flame retardant is 1:100.

[0018] Preferably, the platinum flame retardant is 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex.

[0019] Preferably, the PT content of the 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex is 4500-5200 ppm; further preferably, the PT content of the 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex is 5000 ppm.

[0020] Preferably, the catalyst is a two-component platinum catalyst.

[0021] Preferably, the melting temperature of the phenyl polyester silicone wax is 50-70°C; further preferably, the melting temperature of the phenyl polyester silicone wax is 55-65°C.

[0022] Preferably, the elastic silicone resin material comprises the following components by weight: 100 parts of a solid silicone resin polymer containing a phenyl functional group, 80-120 parts of an addition-vulcanized silicone rubber, 0.1-0.3 parts of a platinum flame retardant, 10-30 parts of aluminum hydroxide, 0.5-0.8 parts of a two-component platinum catalyst, and 0.5-2 parts of a phenyl polyester silicone wax.

[0023] The technical solution of the present invention uses solid silicone resin containing phenyl functional groups as the main substrate, which can give the material excellent oxidation stability, thermal stability and weather resistance, electrical insulation and other functions. In addition, the mechanism of only using solid phenyl silicone resin is that it is a cross-linked semi-inorganic polymer with -Si-O-Si- as the main chain and organic groups connected to the silicon atoms. This structure determines that phenyl silicone resin has unique properties, which has both the characteristics of carbon skeleton plastics and the characteristics of silicon materials. There are some free positions and carbon-silicon bonds on the molecular chain of phenyl silicone resin, which makes it thermoplastic, and is also the main application mechanism of this application. When the phenyl silicone resin is heated to a certain temperature, the molecular chain breaks under the action of the carbon-silicon bond, forming free radicals and initiating a cross-linking reaction to form a three-dimensional network structure of silicon-oxygen compounds, thereby achieving a reinforcement effect. This kind of organic and inorganic polymer exhibits the solid property of glass below the melting point (room temperature) and the melt property of softening and melting above the melting point. This property is used in shape memory function and presents two different forms: namely, at room temperature, solid phenyl silicone resin is in solid state, freezing the molecular chain movement of elastic silicone resin material, playing the role of "frozen chain"; when the material is heated to above the softening point of solid phenyl silicone resin, the molecular chain of the material is relaxed, playing the role of "thawing".

[0024] The addition vulcanized silicone rubber is added to the solid phenyl silicone resin. The purpose is to use the addition type silicone rubber to maintain elasticity for a long time in the temperature range of -65 to 200 ° C. It has excellent electrical properties and chemical stability, water resistance, ozone resistance, radiation resistance, weathering resistance, hydrophobic moisture resistance, shock resistance, good low compression deformation, low flammability; it has the advantages of physiological inertness, non-toxicity, tastelessness, and the vulcanization speed can be smoothly controlled by temperature. In order to make it have elastic function, good mechanical properties, bending fatigue resistance, high tear resistance, etc., the addition type vulcanized silicone rubber used in this technical solution has the important characteristics of 40A-50A, the tensile strength after the second stage vulcanization is above 9MPa, the elongation at break is above 800%, and the tear strength is greater than 30N / mm. It gives the material good mechanical properties, softness, etc.

[0025] In order to meet the flame retardant properties of the material, a small amount of platinum flame retardant is added to the composite flame retardant, and a small amount of hydroxide flame retardant is used to give the material good flame retardant properties, so that it can maintain the insulation properties of the material to the greatest extent, low hardness, bending fatigue resistance, high temperature resistance and low temperature resistance. Platinum flame retardant is 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex, which is a highly active and highly catalytic platinum catalyst that can efficiently catalyze the addition reaction of Si-Vi and Si-H without side reactions. Even if the pure platinum flame retardant is added in a high amount, it is actually unable to achieve the function of flame retardant silicone rubber, so it needs to be used in conjunction with hydroxide flame retardant.

[0026] In order to satisfy the shape memory function of the material, a two-component platinum catalyst needs to be added to make the silicone rubber molecular chain of the addition-vulcanized silicone rubber produce thermal crosslinking at room temperature / high temperature. It should be noted that the addition-vulcanized silicone rubber used in this technical solution has the important characteristics of 40A-50A, the tensile strength after two-stage vulcanization is above 9MPa, the elongation at break is above 800%, and the tear strength is greater than 30N / mm. It gives the material good mechanical properties, softness, etc., that is, its mechanical properties are obtained through vulcanization crosslinking. At the same time, it should be noted that the important feature of the use of solid phenyl silicone resin in this technical solution is that pure cross-linked silicone rubber does not have a heat shrinkage function, while the addition of solid phenyl silicone resin with a melting point of 70-90°C makes use of the fact that after processing, the solid phenyl silicone resin presents a glassy solid property below the melting point (normal temperature), and a softening property above the melting point. This property is used in the shape memory function and presents two different forms: that is, at normal temperature, the solid phenyl silicone resin is solid, freezing the network structure formed by the vulcanized cross-linked silicone rubber, restricting the movement of the molecular chains of the silicone resin material, and playing a "frozen chain" role. When the material is heated to above the softening point of the solid phenyl silicone resin, the network structure formed by the vulcanized cross-linked silicone rubber is relaxed, playing a "thawing" role, thereby realizing the heating shrinkage function. In this process, the main role played by the solid phenyl silicone resin is to support the expansion and cooling shaping function of the silicone rubber after vulcanization and cross-linking, and does not participate in the vulcanization and cross-linking of the silicone rubber.

[0027] In order to meet the processing performance of the material, phenyl polyester silicone wax is added. Its purpose and function is that the functional groups contained in the phenyl polyester silicone wax are consistent with the functional groups contained in the solid phenyl silicone resin, which not only has good compatibility, but also improves the processing performance of the material, making it easier to fully and evenly mix the various component materials.

[0028] On the other hand, the present invention provides a method for preparing an elastic silicone sleeve with shape memory function, characterized in that the elastic silicone material described above is used as a raw material, and the method comprises the following steps:

[0029] S1: heat and knead solid silicone resin polymer containing phenyl functional groups, silicone rubber, composite flame retardant, and phenyl polyester silicone wax, and vacuum to obtain premixed polymer A;

[0030] S2: premixed polymer A is cooled to ≤30°C, refined, and a two-component platinum catalyst is added for secondary refining to obtain rubber material B;

[0031] S3: The rubber material B is extruded at a temperature of ≤30°C, formed into a tubular tube embryo through a mold, and is heat cured and cross-linked at 500-650°C, and further heat cross-linked at 200-380°C to obtain a tube embryo C;

[0032] S4: The tube embryo C is heated at 130-280° C. to soften, expanded to 1-3 times, and cooled at 0-22° C. to set the tube, thereby obtaining an elastic silicone sleeve with shape memory function.

[0033] Preferably, the heating temperature in S1 is 90-115°C; further preferably, the heating temperature in S1 is 100-105°C.

[0034] Preferably, the kneading speed in S1 is 5-55 Rpm, and the kneading time is 10-45 min; further preferably, the kneading speed in S1 is 10-50 Rpm, and the kneading time is 15-40 min.

[0035] Preferably, the vacuum degree of the vacuum described in S1 is -0.03 to -1 MPa, and the time is 1 to 10 min; further preferably, the vacuum degree of the vacuum described in S1 is -0.06 to -1 MPa, and the time is 1 to 5 min.

[0036] Preferably, the specific conditions of refining described in S2 are: the temperature of the refining roller is ≤30°C, the refining roller spacing is 10-20mm, refining is 10-20 times, the refining roller spacing is 1-2mm, refining is 2-3 times, and finally the sheet is 20-30mm.

[0037] Further preferably, the specific conditions of the secondary refining described in S2 are: the temperature of the refining roll is 20-25°C, the refining roll spacing is 8-10mm, refining is 15-20 times, the refining roll spacing is 1-2mm, refining is 2-3 times, and finally the sheet is 30mm.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. The technical solution of the present invention optimizes the components and ratios of the elastic silicone resin material, selects solid silicone resin containing phenyl functional groups as the main base material, and gives the material excellent oxidation stability, thermal stability, weather resistance, and electrical insulation. At the same time, the glassy property below the melting point is utilized, and combined with the vulcanized cross-linked silicone rubber, it is given a shape memory function after cooling and setting after expansion, and a contraction function can be achieved when heated above the melting point; the addition type silicone rubber is used to give the material good mechanical properties and softness; the platinum flame retardant cooperates with a small amount of aluminum hydroxide flame retardant to give the material good flame retardant properties; in order to meet the shape memory function of the material, a two-component platinum catalyst is added to make the silicone molecular chain of the addition type vulcanized silicone rubber produce thermal crosslinking at room temperature / high temperature; while playing a good compatibility, the phenyl polyester silicone wax improves the processing performance of the material, making it convenient for the full and uniform mixing of the various component materials.

[0040] 2. The elastic silicone heat shrinkable tube prepared by the present invention has good flame retardancy, high tear strength, low hardness, resistance to bending fatigue, and resistance to high and low temperature harsh environments. It can be used in scenarios such as electric-driven vehicles and the electronics industry for bending fatigue and high and low temperature insulation protection. DETAILED DESCRIPTION

[0041] In order to make the technical means, creative features, purpose and effect of the present invention easy to understand, the present invention is further explained below in conjunction with specific embodiments, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without making creative work all belong to the protection scope of the present invention. It is worth noting that the raw materials used in the present invention are all common commercial products, and their sources are not specifically limited. The technology and scientific terms used in the embodiments have the meanings commonly understood by those of ordinary skill in the art to which the present invention belongs.

[0042] Raw materials described in this application:

[0043] The solid silicone resin containing phenyl functional groups has a white solid appearance. The raw material source is preferably a solid phenyl silicone resin produced by Guangzhou Carbon Silicon New Materials Co., Ltd., model SIC-6168P.

[0044] The addition-vulcanized silicone rubber is a translucent colloid in appearance. Its main feature is the two-stage tensile strength (after vulcanization under the test conditions of A / B (0.5 / 0.7) 200℃ for 2h, the typical value of tensile strength is ≥9MPa, and the typical value of elongation at break is ≥800%. Tear strength is ≥30kN / m). The raw material source is preferably the addition-vulcanized silicone rubber of Xin'an Tianyu Silicone Co., Ltd., model TY6145-40P.

[0045] The platinum flame retardant is 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex, and its PT content is 5000ppm. The raw material source is preferably PT-5000FR029 (powder) produced by Kejunchi New Materials Co., Ltd.

[0046] The maximum particle size of aluminum hydroxide is required to be Dmax≤10um, and the source of raw materials is not limited.

[0047] Two-component platinum catalyst: A / B vulcanizing agent, the main components of agent A are platinum and hydrogen-containing silicone oil, with a transparent colloid appearance, which acts as a catalyst; the main components of agent B are inhibitors and cross-linking agents. The raw material source is preferably HC-100A and HC-100B produced by Guilin Yutian New Materials Co., Ltd.

[0048] Example 1

[0049] 100 parts of solid silicone resin polymer containing phenyl functional groups, 80 parts of addition-vulcanized silicone rubber, 0.1 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex, 10 parts of aluminum hydroxide, 0.5 parts of two-component platinum catalyst, and 0.5 parts of phenyl polyester silicone wax.

[0050] The preparation method of the elastic silicone sleeve with shape memory function comprises the following steps S1-S5:

[0051] S1. Heating and vacuum kneading the mixture: Add the solid silicone resin polymer containing phenyl functional groups, addition vulcanized silicone rubber, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex, aluminum hydroxide, and phenyl polyester silicone wax into an M-type double-arm kneader, and heat the kneader to 105°C. The kneading speed is within the range of 40Rpm for 30 minutes until the solid silicone resin is completely melted and mixed evenly with the addition vulcanized rubber. Then start the vacuum device, set the vacuum degree at -0.06MPa, and keep it for 2 minutes to obtain the premixed polymer A. At this time, the solid silicone resin forms a continuous phase after melting, and the addition vulcanized silicone rubber presents a discontinuous phase. The premixed polymer A will become brittle after cooling at room temperature.

[0052] S2. Then it is completely cooled to 20°C, added to the open mill for refining, and the specific conditions for refining are: the temperature of the open mill is set to 20°C, the distance between the open mill rolls is 20mm, refining is 20 times, the distance between the open mill rolls is 1mm, refining is 3 times, and finally the sheet is discharged at 25mm. The addition-type vulcanized silicone rubber component is in a continuous phase again, and the material is in a rubber state. Then the two-component platinum catalyst is added in proportion for secondary refining. The specific conditions for secondary refining are: the temperature of the open mill roll is set to 25°C, the distance between the open mill rolls is 10mm, refining is 20 times, the distance between the open mill rolls is 1mm, and refining is 3 times. Finally, the sheet is discharged at 30mm. The rubber material B for preparing the elastic silicone sleeve with shape memory function is obtained.

[0053] S3. The rubber material B is extruded through a silicone extruder at room temperature, formed into a tubular tube embryo through a mold, and then subjected to thermosetting vulcanization cross-linking in a high-temperature vulcanization furnace at 500° C., and then further subjected to thermal cross-linking in a high-temperature vulcanization tank at 250° C. to obtain a cross-linked tube embryo C.

[0054] S4 heats and softens the tube embryo C to 160°C, expands it to 1.5 times using an expander and an expansion mold, and cools it to shape using low-temperature cold water below 20°C, thereby obtaining an elastic silicone sleeve with shape memory function.

[0055] Example 2

[0056] 100 parts of solid silicone resin polymer containing functional groups, 100 parts of addition-vulcanized silicone rubber, 0.2 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex, 20 parts of aluminum hydroxide, 0.5 parts of two-component platinum catalyst, and 1 part of phenyl polyester silicone wax.

[0057] The difference between the steps S1-S5 in Example 1 is that:

[0058] In S1, the difference is that the kneading machine temperature is set to 100°C, the kneading machine speed is set to 50 Rpm, the kneading time is 35 min, the vacuum degree is set to -0.08 MPa, and the vacuuming time is set to 5 min;

[0059] The process conditions of steps S2-S3 are the same. In S4, the tube blank C is heated and softened at 180°C and expanded to 2 times using an expander and an expansion mold. Other operations are the same.

[0060] Example 3

[0061] 100 parts of solid silicone resin polymer containing functional groups, 120 parts of addition-vulcanized silicone rubber, 0.3 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex, 30 parts of aluminum hydroxide, 0.8 parts of two-component platinum catalyst, and 2 parts of phenyl polyester silicone wax.

[0062] The difference between the steps S1-S5 in Example 1 is that:

[0063] In S1, the difference is that the kneading machine temperature is set to 110°C, the kneading machine speed is set to 30Rpm, the kneading time is 38min, the vacuum degree is set to -1MPa, and the vacuuming time is set to 1min;

[0064] The process conditions of steps S2-S3 are the same. In S4, the tube blank C is heated and softened at 200°C and then expanded to 3 times using an expander and an expansion die. Other operations are the same.

[0065] Comparative Example 1

[0066] Compared with Example 1, only the addition-vulcanized silicone rubber was changed to a general-purpose precipitation silicone rubber with a hardness of 40A and a half-moon tear strength of 8 kN / m. Other operations were the same.

[0067] Comparative Example 2

[0068] The difference from Example 1 is that no platinum flame retardant is added. Other operations are the same.

[0069] Comparative Example 3

[0070] Compared with Example 1, only the addition-vulcanized silicone rubber was changed to a general-purpose fumed silicone rubber with a hardness of 48A and a half-moon tear strength of 14 kN / m. Other operations were the same.

[0071] Comparative Example 4

[0072] Compared with Example 1, only the number of components is changed, as follows:

[0073] 80 parts of solid silicone resin polymer containing functional groups, 130 parts of addition-cured silicone rubber, 0.5 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex, 40 parts of aluminum hydroxide, 1.5 parts of two-component platinum catalyst, and 3 parts of phenyl polyester silicone wax. Other operations are the same.

[0074] Comparative Example 5

[0075] Compared with Example 1, only the solid silicone resin polymer containing functional groups is changed to liquid phenyl silicone resin. Other operations are the same.

[0076] Comparative Example 6

[0077] Compared with Example 1, an equal amount of LDPE was used to replace the phenyl silicone resin. Other operations were the same.

[0078] Comparative Example 7

[0079] Compared with Example 1, an equal amount of EVA was used to replace the phenyl silicone resin. Other operations were the same.

[0080] Comparative Example 8

[0081] Compared with Example 1, the phenyl polyester silicone wax was removed. Other operations were the same.

[0082] The test results of the casing performance obtained by combining the casing preparation method according to the above-mentioned Examples 1-3 and Comparative Examples 1-8 are shown in Table 1-2 below:

[0083] Table 1. Performance test results of samples in the examples

[0084]

[0085]

[0086] Table 2. Comparative sample performance test results

[0087]

[0088]

[0089]

[0090] As shown in the data in Table 1-2: Comparative Example 1 uses precipitated silicone rubber and Comparative Example 3, the tear strength of the material itself is low, resulting in its bending fatigue resistance and tear strength being unqualified; Comparative Example 2 does not add platinum flame retardant, only adds aluminum hydroxide flame retardant, and the material cannot meet the V0 flame retardant requirements; Comparative Example 4 has a low amount of phenyl silicone resin added, a high amount of silicone rubber added, and a high amount of flame retardant added, resulting in the material's bending fatigue resistance and tear strength not meeting the standards; Comparative Example 5 uses liquid phenyl silicone resin, and the low-temperature bending resistance, flame retardancy and tear strength are all unqualified. At the same time, the material lacks low-temperature curing function after expansion and cannot be expanded and fixed. Comparative Example 6 uses LDPE to replace solid phenyl silicone resin, and the material's heat aging resistance and other properties are significantly reduced and unqualified. Comparative Example 7 uses EVA to replace solid phenyl silicone resin, and the material's heat aging resistance and other properties are significantly reduced and unqualified. Comparative Example 8 does not add phenyl polyester silicone wax, resulting in reduced compatibility of the components of the system, and the bending fatigue resistance index does not meet the requirements.

[0091] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. An elastic silicone material with shape memory function, characterized in that: The invention comprises the following components: a solid silicone resin polymer containing a phenyl functional group, silicone rubber, a composite flame retardant, a catalyst and a phenyl polyester silicone wax.

2. The elastic silicone material according to claim 1, characterized in that: The invention comprises the following components in parts by mass: 90-110 parts of solid silicone resin polymer containing phenyl functional groups, 75-125 parts of silicone rubber, 9-35 parts of composite flame retardant, 0.4-1 parts of catalyst and 0.3-2.5 parts of phenyl polyester silicone wax.

3. The elastic silicone material according to claim 1, characterized in that: The silicone rubber is addition vulcanized silicone rubber.

4. The elastic silicone material according to claim 3, characterized in that: The hardness of the addition-vulcanized silicone rubber is Shore 35A-55A, the tensile strength after two-stage vulcanization is ≥8MPa, the elongation at break is ≥750%, and the tear strength is ≥25N / mm.

5. The elastic silicone material according to claim 1, characterized in that: The composite flame retardant is a combination of platinum flame retardant and aluminum hydroxide.

6. The elastic silicone material according to claim 5, characterized in that: The mass ratio of the platinum flame retardant to aluminum hydroxide is 1:90-110.

7. The elastic silicone material according to claim 5, characterized in that: The platinum flame retardant is 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex, and its PT content is 5000ppm.

8. The elastic silicone material according to claim 1, characterized in that: The catalyst is a two-component platinum catalyst.

9. The elastic silicone material according to claim 1, characterized in that: The melting temperature of the phenyl polyester silicone wax is 50-70°C.

10. A method for preparing an elastic silicone sleeve with shape memory function, characterized in that: Using the elastic silicone resin material according to any one of claims 1 to 9 as a raw material, the method comprises the following steps: S1: heat and knead solid silicone resin polymer containing phenyl functional groups, silicone rubber, composite flame retardant, and phenyl polyester silicone wax, and vacuum to obtain premixed polymer A; S2: premixed polymer A is cooled to ≤30°C, refined, and a two-component platinum catalyst is added for secondary refining to obtain rubber material B; S3: The rubber material B is extruded at a temperature of ≤30°C, formed into a tubular tube embryo through a mold, and is heat cured and cross-linked at 500-650°C, and further heat cross-linked at 200-380°C to obtain a tube embryo C; S4: The tube embryo C is heated at 130-280° C. to soften, expanded to 1-3 times, and cooled at 0-22° C. to set, thereby obtaining an elastic silicone sleeve with shape memory function.

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