Single-component addition type liquid silicone rubber and preparation method thereof

Abstract

The invention relates to single-component addition type liquid silicone rubber and a preparation method of the single-component addition type liquid silicone rubber. The single-component addition type liquid silicone rubber is prepared from the following raw materials and a platinum catalyst: 100 parts of double-end vinyl silicone oil, 1-7 parts of end-side vinyl silicone oil, 10-50 parts of fumed silica, 0.5-5 parts of a silazane treating agent, 1-5 parts of end-side hydrogen-containing silicone oil and 0.05-0.5 part of an inhibitor, the silazane treating agent is prepared from hexamethyl disilazane, divinyl tetramethyl disilazane and tetramethyl disilazane; the viscosity of the end side vinyl silicone oil ranges from 5000 mPa * s to 150000 mPa * s; and the viscosity of the end side hydrogen-containing silicone oil is 100 mPa.s to 1000 mPa.s. The single-component addition type liquid silicone rubber disclosed by the invention not only has excellent mechanical properties, but also has extremely low compression set.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sealant, and particularly relates to a single-component addition type liquid silicone rubber and a preparation method thereof. BACKGROUND

[0002] The CIPG flat sealing process, also known as the dry assembly method, integrates the advantages of the traditional sealing ring process and the FIPG process. The specific operation process of the CIPG process is as follows: an automatic dispensing machine is used to apply liquid sealant (mostly single-component liquid silicone rubber) to the sealing surface, and ensure that the sealant is evenly covered. After high-temperature curing and molding, mechanical locking (i.e. compression) is used to achieve sealing protection. Since the CIPG process mainly relies on the compression and resilience of the sealant to achieve sealing, if the compression permanent deformation is too high, it will lead to sealing failure during long-term use. Therefore, it is particularly important to reduce the compression permanent deformation of the sealant.

[0003] Patent CN105385167A discloses an addition type silicone rubber and a preparation method thereof. Specifically, diallyl phthalate is used to modify white carbon black to improve the adhesion of the silicone rubber to PET and PBT. However, the influence of compression permanent deformation is not mentioned. Patent CN109705351A discloses a dendritic polysiloxane and a preparation method thereof, and an addition type liquid silicone flat sealant and a preparation method thereof. Specifically, a self-synthesized dendritic polysiloxane is used as a base polymer to improve the tensile strength of the silicone sealant. However, the influence of compression permanent deformation is not mentioned. Patent CN106590520A discloses a selectively self-adhesive liquid silicone rubber and a preparation method thereof. Specifically, a method of adding vinyl hydroxy silicone oil during base material compounding is disclosed to improve the adhesion strength of the selectively self-adhesive liquid silicone rubber to PC, PBT and nylon 6, and to improve the strength of the silicone rubber. However, the influence of compression permanent deformation is not mentioned. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a single-component addition type liquid silicone rubber with lower compression permanent deformation.

[0005] The technical solution for achieving the above purpose comprises the following.

[0006] In a first aspect, the present application provides a single-component addition type liquid silicone rubber, which is prepared from raw materials comprising the following components and a platinum catalyst, in parts by weight:

[0007] double-end vinyl silicone oil 100 parts

[0008] end-side vinyl silicone oil 1-7 parts

[0009] fumed silica 10-50 parts

[0010] silazane treating agent 0.5-5 parts

[0011] end-capped hydrogen-containing silicone oil 1-5 parts

[0012] inhibitor 0.05-0.5 parts

[0013] The silazane treating agent is composed of hexamethyldisilazane, divinyltetramethyldisilazane and tetramethyldisilazane;

[0014] The viscosity of the end-capped vinyl silicone oil is 5000 mPa·s-150000 mPa·s;

[0015] The viscosity of the end-capped hydrogen-containing silicone oil is 100 mPa·s-1000 mPa·s.

[0016] In a second aspect, the application provides a preparation method of the single-component addition type liquid silicone rubber, comprising the following steps:

[0017] The double-end vinyl silicone oil, the end-capped vinyl silicone oil and the silazane treating agent are put into a kneader, the fumed silica is put in batches, and kneading is carried out at a temperature of 10-40℃ for 1-3h, and then the temperature is raised to 150-180℃ and vacuum is applied, and kneading is carried out for 2-4h to obtain a base material;

[0018] The base material, the end-capped hydrogen-containing silicone oil and the inhibitor are mixed uniformly, and then the platinum catalyst is added and mixed uniformly under vacuum to obtain the single-component addition type liquid silicone rubber.

[0019] The application has the following beneficial effects:

[0020] The fumed silica is modified by a mixed treating agent of hexamethyldisilazane, divinyltetramethyldisilazane and tetramethyldisilazane, so that the surface of the fumed silica has both vinyl and silicon-hydrogen crosslinking reaction sites, and can react with both the vinyl silicone oil and the hydrogen-containing crosslinking agent, thereby enhancing the binding force between the polymer and the fumed silica; the high-viscosity end-capped vinyl silicone oil is used as the second polymer, and the high-viscosity end-capped hydrogen-containing silicone oil is used as the crosslinking agent, and because of the large molecular weight, a more compact crosslinking network is formed after curing, which not only has high mechanical strength, but also has extremely low compression set. Under the synergistic cooperation of the above components, the single-component addition type liquid silicone rubber prepared by cooperating the double-end vinyl silicone oil and other components has not only excellent mechanical properties, but also extremely low compression set. DETAILED DESCRIPTION

[0021] For the purposes of the present invention, a more complete description of the application will be presented. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention is more thorough and complete.

[0022] The experimental methods in the following examples, unless otherwise specified, are generally carried out according to the conventional conditions or according to the conditions recommended by the manufacturers. The various common chemical reagents used in the examples are commercially available products.

[0023] Unless otherwise defined, all technical and scientific terms used within the scope of the present invention have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention belongs. The terminology used in the description of the present invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used in the description of the present invention, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0024] In addition, as used in the present invention, the term "or" is the inclusive "or" and is equivalent to the term "and / or", unless the context clearly indicates otherwise. The term "based on" is not exclusive and allows for being based on other factors not described, unless the context clearly indicates otherwise. In addition, throughout the specification, the meaning of "a", "an", and "the" include plural references. The meaning of "in" includes "in" and "on".

[0025] In some embodiments thereof relates to a one-component addition type liquid silicone rubber, prepared from raw materials comprising the following components, and a platinum catalyst, in parts by weight:

[0026] Both end vinyl silicone oil 100 parts

[0027] End side vinyl silicone oil 1-7 parts

[0028] Fumed silica 10-50 parts

[0029] Silazane treating agent 0.5-5 parts

[0030] End side hydrogen-containing silicone oil 1-5 parts

[0031] Inhibitor 0.05-0.5 parts;

[0032] The silazane treating agent consists of hexamethyldisilazane, divinyltetramethyldisilazane, and tetramethyldisilazane;

[0033] The viscosity of the end side vinyl silicone oil is 5000 mPa·s ~ 150000 mPa·s;

[0034] The viscosity of the end-side hydrogen-containing silicone oil is 100 mPa·s-1000 mPa·s.

[0035] The double-end vinyl silicone oil in the present application is a polydimethylsiloxane with one Si-vinyl group at each of the two ends of the molecular chain, and its molecular structure formula is: CH2=CH-Si(CH3)2O[(CH3)2SiO] n (CH3)2Si-CH=CH2.

[0036] The end-side vinyl silicone oil in the present application is a polydimethylsiloxane with one Si-vinyl group at each of the two ends of the molecular chain, and its molecular structure formula is: CH2=CH-Si(CH3)2O[(CH3)2SiO] n [(CH3)(CH=CH2)SiO] m (CH3)2Si-CH=CH2.

[0037] The end-side hydrogen-containing silicone oil in the present application is a polydimethylsiloxane with one Si-H group at each of the two ends of the molecular chain, and its molecular structure formula is: H-Si(CH3)2O[(CH3)2SiO] n [(CH3)(H)SiO] m (CH3)2Si-H.

[0038] In some preferred embodiments, the one-component addition type liquid silicone rubber is prepared from raw materials comprising the following components and a platinum catalyst:

[0039] Double-end vinyl silicone oil 100 parts

[0040] End-side vinyl silicone oil 3-5 parts

[0041] Fumed silica 25-35 parts

[0042] Silazane treating agent 2-3.5 parts

[0043] End-side hydrogen-containing silicone oil 1.3-3 parts

[0044] Inhibitor 0.05-0.5 parts.

[0045] In some preferred embodiments, the silazane treating agent is composed of hexamethyldisilazane, divinyltetramethyldisilazane and tetramethyldisilazane in a mass ratio of 1.0:0.05-0.5:0.05-0.5.

[0046] In some preferred embodiments, the silazane treatment agent consists of hexamethyldisilazane, divinyltetramethyldisilazane and tetramethyldisilazane in a mass ratio of 1.0:0.1-0.3:0.1-0.3.

[0047] In some preferred embodiments, the silazane treatment agent consists of hexamethyldisilazane, divinyltetramethyldisilazane and tetramethyldisilazane in a mass ratio of 1.0:0.2-0.25:0.2-0.25.

[0048] In some preferred embodiments, the viscosity of the end-capped vinyl silicone oil is 30000 mPa s-100000 mPa s, preferably 50000 mPa s-80000 mPa s.

[0049] In some preferred embodiments, the vinyl content of the end-capped vinyl silicone oil is 1.0 wt%-10 wt%, preferably 2.0 wt%-5.0 wt%, more preferably 3.0 wt%-4.0 wt%.

[0050] In some preferred embodiments, the viscosity of the end-capped hydrogen-containing silicone oil is 150 mPa s-500 mPa s, more preferably 200 mPa s-300 mPa s.

[0051] In some preferred embodiments, the hydrogen content of the end-capped hydrogen-containing silicone oil is 0.5 wt%-1.5 wt%, more preferably 0.6 wt%-1.0 wt%.

[0052] In some preferred embodiments, the viscosity of the double-end vinyl silicone oil is 2000 mPa s-50000 mPa s, more preferably 5000 mPa s-30000 mPa s, more preferably 15000 mPa s-25000 mPa s.

[0053] In some preferred embodiments, the specific surface area of the fumed silica is 100 m 2 / g-400 m 2 / g, more preferably 300 m 2 / g-350 m 2 / g.

[0054] In some preferred embodiments, the inhibitor is selected from one or more of 1-ethynyl-1-cyclohexanol, tetramethyltetra-vinylcyclotetrasiloxane, 2-methyl-3-butynyl-2-ol, 3-methyl-1-hexynyl-3-ol, 3,5-dimethyl-1-hexynyl-3-ol and 3-methyl-1-dodecyn-3-ol.

[0055] In some preferred embodiments, the platinum catalyst is selected from one or more of chloroplatinic acid, chloroplatinic acid-isopropyl alcohol complex and Karstedt's catalyst.

[0056] In some preferred embodiments, the content of the platinum catalyst is 0.5 ppm to 10 ppm by mass of platinum, more preferably 2 ppm to 6 ppm.

[0057] The one-component addition type liquid silicone rubber of the present application can be prepared by conventional methods in the art, for example, in some embodiments of the present application, a method for preparing the one-component addition type liquid silicone rubber is provided, which comprises the following steps:

[0058] The double-end vinyl silicone oil, end-side vinyl silicone oil and silazane treating agent are put into a kneader, the fumed silica is put in batches, kneading at a temperature of 10℃ to 40℃ for 1h to 3h, then the temperature is raised to 150℃ to 180℃ (preferably 155℃ to 170℃) and vacuumized, kneading for 2h to 4h to obtain a base material;

[0059] The base material, end-side hydrogen-containing silicone oil and inhibitor are mixed uniformly, then the platinum catalyst is added and mixed uniformly under vacuum to obtain the one-component addition type liquid silicone rubber.

[0060] In the following examples, the room temperature refers to 15℃ to 25℃.

[0061] The test condition of the viscosity of the present application is determined according to the standard of GB / T 2794-1995 "Determination of viscosity of adhesives" using a rotational viscometer at 25℃.

[0062] The present application is further described in detail in combination with specific examples.

[0063] In the following examples, the raw materials used are as follows:

[0064] Double-end vinyl silicone oil: Zhejiang Runhe Organic Silicon New Material Co., Ltd., RH-Vi302.

[0065] End-side vinyl silicone oil: Guangzhou Tianjiang High-tech Material Co., Ltd.

[0066] End-side hydrogen-containing silicone oil: Guangzhou Tianjiang High-tech Material Co., Ltd.

[0067] Fumed silica: Aiken Organic Silicon (Shanghai) Co., Ltd., ES-320.

[0068] Hexamethyldisilazane: Anhui Aiyouta Silicone Co., Ltd., IOTA 011.

[0069] Divinyltetramethyldisilazane: Anhui Aiyouta Silicone Co., Ltd., IOTA-51001.

[0070] Tetramethyldisilazane: Guangzhou Yuanda New Material Co., Ltd., TMDS.

[0071] 1-ethynyl-1-cyclohexanol: Wuhan Anruike Material Co., Ltd., UM-600.

[0072] Kast catalyst: Shanghai Yuhuan Chemical Co., Ltd., PC-52.

[0073] Example 1

[0074] The one-component addition type liquid silicone rubber provided in this example has the following raw material composition:

[0075]

[0076]

[0077] The specific preparation method includes the following steps:

[0078] (1) Put the double-end vinyl silicone oil, end-side vinyl silicone oil, hexamethyldisilazane, divinyltetramethyldisilazane, and tetramethyldisilazane into a kneader, batch in fumed silica, knead at room temperature for 2 h, then heat to 160°C and vacuum to above -0.095 MPa, knead for 3 h to obtain a base material;

[0079] (2) Put the base material, end-side hydrogen-containing silicone oil, and inhibitor into a planetary mixer, stir for 30 min after the end of the batch to mix evenly;

[0080] (3) Put the platinum catalyst into the planetary mixer, stir and vacuum to above -0.095 MPa for 30 min to mix, and obtain the one-component addition type liquid silicone rubber.

[0081] Example 2

[0082] The one-component addition type liquid silicone rubber provided in this example has the following raw material composition:

[0083]

[0084]

[0085] The specific preparation method includes the following steps:

[0086] (1) Put the double-end vinyl silicone oil, end-side vinyl silicone oil, hexamethyldisilazane, divinyltetramethyldisilazane, and tetramethyldisilazane into a kneader, batch in fumed silica, knead at room temperature for 2 h, then heat to 160°C and vacuum to above -0.095 MPa, knead for 3 h to obtain a base material;

[0087] (2) Put the base material, end-side hydrogen-containing silicone oil and inhibitor into a planetary mixer, stir for 30 min after the completion of the feeding until the mixture is uniform;

[0088] (3) Put the platinum catalyst into the planetary mixer, stir and vacuumize to above -0.095 MPa for 30 min, and then obtain the one-component addition type liquid silicone rubber.

[0089] Example 3

[0090] The one-component addition type liquid silicone rubber provided in the example has the following raw material composition:

[0091]

[0092]

[0093] The specific preparation method includes the following steps:

[0094] (1) Put the double-end vinyl silicone oil, end-side vinyl silicone oil, hexamethyl disilazane, divinyl tetramethyl disilazane and tetramethyl disilazane into a kneader, feed the fumed silica in batches, knead at room temperature for 2 h, then heat to 160°C and vacuumize to above -0.095 MPa, and knead for 3 h to obtain a base material;

[0095] (2) Put the base material, end-side hydrogen-containing silicone oil and inhibitor into a planetary mixer, stir for 30 min after the completion of the feeding until the mixture is uniform;

[0096] (3) Put the platinum catalyst into the planetary mixer, stir and vacuumize to above -0.095 MPa for 30 min, and then obtain the one-component addition type liquid silicone rubber.

[0097] Example 4

[0098] The one-component addition type liquid silicone rubber provided in the example has the following raw material composition:

[0099]

[0100]

[0101] The specific preparation method includes the following steps:

[0102] (1) Put the double-end vinyl silicone oil, end-side vinyl silicone oil, hexamethyl disilazane, divinyl tetramethyl disilazane and tetramethyl disilazane into a kneader, feed the fumed silica in batches, knead at room temperature for 2 h, then heat to 160°C and vacuumize to above -0.095 MPa, and knead for 3 h to obtain a base material;

[0103] (2) Put the base material, end-side hydrogen-containing silicone oil and inhibitor into a planetary mixer, stir for 30 min after the completion of the feeding until the mixture is uniform;

[0104] (3) Put the platinum catalyst into the planetary mixer, stir and vacuumize to above -0.095 MPa for 30 min, and then obtain the one-component addition type liquid silicone rubber.

[0105] Example 5

[0106] The one-component addition type liquid silicone rubber provided in this example has the following raw material composition:

[0107]

[0108]

[0109] The specific preparation method includes the following steps:

[0110] (1) Put the double-end vinyl silicone oil, end-side vinyl silicone oil, hexamethyl disilazane, divinyl tetramethyl disilazane and tetramethyl disilazane into a kneader, feed the fumed silica in batches, knead at room temperature for 2 h, then heat to 160°C and vacuumize to above -0.095 MPa, and knead for 3 h to obtain a base material;

[0111] (2) Put the base material, end-side hydrogen-containing silicone oil and inhibitor into a planetary mixer, stir for 30 min after the completion of the feeding until the mixture is uniform;

[0112] (3) Put the platinum catalyst into the planetary mixer, stir and vacuumize to above -0.095 MPa for 30 min, and then obtain the one-component addition type liquid silicone rubber.

[0113] Comparative Example 1

[0114] The one-component addition type liquid silicone rubber provided in this comparative example, compared with Example 4, does not add end-side vinyl silicone oil, and has the following raw material composition:

[0115]

[0116]

[0117] The specific preparation method includes the following steps:

[0118] (1) Put the double-end vinyl silicone oil, hexamethyl disilazane, divinyl tetramethyl disilazane and tetramethyl disilazane into a kneader, feed the fumed silica in batches, knead at room temperature for 2 h, then heat to 160°C and vacuumize to above -0.095 MPa, and knead for 3 h to obtain a base material;

[0119] (2) Put the base material, end-side hydrogen-containing silicone oil and inhibitor into the planetary mixer, stir for 30 min after the completion of the feeding until the mixture is uniform;

[0120] (3) Put the platinum catalyst into the planetary mixer, stir and vacuumize to above -0.095 MPa for 30 min, and then obtain the one-component addition type liquid silicone rubber.

[0121] Comparative Example 2

[0122] The one-component addition type liquid silicone rubber provided in the present comparative example has only one kind of silazane treating agent, hexamethyldisilazane, compared with Example 4, and the raw material composition is as follows:

[0123]

[0124]

[0125] The specific preparation method includes the following steps:

[0126] (1) Put the double-end vinyl silicone oil, end-side vinyl silicone oil and hexamethyldisilazane into the kneader, feed the fumed silica in batches, knead at room temperature for 2 h, then heat to 160°C and vacuumize to above -0.095 MPa, and knead for 3 h to obtain the base material;

[0127] (2) Put the base material, end-side hydrogen-containing silicone oil and inhibitor into the planetary mixer, stir for 30 min after the completion of the feeding until the mixture is uniform;

[0128] (3) Put the platinum catalyst into the planetary mixer, stir and vacuumize to above -0.095 MPa for 30 min, and then obtain the one-component addition type liquid silicone rubber.

[0129] Comparative Example 3

[0130] The one-component addition type liquid silicone rubber provided in the present comparative example has a smaller viscosity of the end-side hydrogen-containing silicone oil compared with Example 5, and the raw material composition is as follows:

[0131]

[0132]

[0133] The specific preparation method includes the following steps:

[0134] (1) Put the double-end vinyl silicone oil, end-side vinyl silicone oil, hexamethyldisilazane, divinyltetramethyldisilazane and tetramethyldisilazane into the kneader, feed the fumed silica in batches, knead at room temperature for 2 h, then heat to 160°C and vacuumize to above -0.095 MPa, and knead for 3 h to obtain the base material;

[0135] (2) Put the base material, end-side hydrogen-containing silicone oil and inhibitor into the planetary mixer, stir for 30 min after the completion of the feeding until the mixture is uniform;

[0136] (3) Put the platinum catalyst into the planetary mixer, stir and vacuumize to above -0.095 MPa for 30 min, and then obtain the one-component addition type liquid silicone rubber.

[0137] Comparative Example 4

[0138] The one-component addition type liquid silicone rubber provided in this comparative example, compared with Example 5, has no end-side vinyl silicone oil added, only one kind of silazane treating agent, hexamethyldisilazane, and a smaller viscosity of end-side hydrogen-containing silicone oil, and the raw material composition is as follows:

[0139]

[0140]

[0141] The specific preparation method includes the following steps:

[0142] (1) Put the double-end vinyl silicone oil, hexamethyldisilazane into the kneader, and batch feed the fumed silica. Knead at room temperature for 2 h, then heat to 160°C and vacuumize to above -0.095 MPa, and knead for 3 h to obtain the base material;

[0143] (2) Put the base material, end-side hydrogen-containing silicone oil and inhibitor into the planetary mixer, stir for 30 min after the completion of the feeding until the mixture is uniform;

[0144] (3) Put the platinum catalyst into the planetary mixer, stir and vacuumize to above -0.095 MPa for 30 min, and then obtain the one-component addition type liquid silicone rubber.

[0145] Comparative Example 5

[0146] The one-component addition type liquid silicone rubber provided in this comparative example, compared with Example 4, has a smaller viscosity of end-side vinyl silicone oil, and the raw material composition is as follows:

[0147]

[0148]

[0149] The specific preparation method includes the following steps:

[0150] (1) Put the double-end vinyl silicone oil, end-side vinyl silicone oil, hexamethyldisilazane, divinyltetramethyldisilazane and tetramethyldisilazane into the kneader, and batch feed the fumed silica. Knead at room temperature for 2 h, then heat to 160°C and vacuumize to above -0.095 MPa, and knead for 3 h to obtain the base material;

[0151] (2) Put the base material, end-side hydrogen-containing silicone oil and inhibitor into a planetary mixer, stir for 30 min after the completion of the feeding until the mixture is uniform;

[0152] (3) Put the platinum catalyst into the planetary mixer, stir and vacuumize to above -0.095 MPa for 30 min, to obtain the one-component addition type liquid silicone rubber.

[0153] Comparative Example 6

[0154] The one-component addition type liquid silicone rubber provided in this comparative example, compared with Example 4, the silazane treating agent is composed of hexamethyldisilazane and divinyltetramethyldisilazane, and the raw material composition is as follows:

[0155]

[0156]

[0157] The specific preparation method includes the following steps:

[0158] (1) Put the double-end vinyl silicone oil, end-side vinyl silicone oil, hexamethyldisilazane and divinyltetramethyldisilazane into a kneader, feed the fumed silica in batches, knead at room temperature for 2 h, then heat to 160°C and vacuumize to above -0.095 MPa, and knead for 3 h to obtain the base material;

[0159] (2) Put the base material, end-side hydrogen-containing silicone oil and inhibitor into a planetary mixer, stir for 30 min after the completion of the feeding until the mixture is uniform;

[0160] (3) Put the platinum catalyst into the planetary mixer, stir and vacuumize to above -0.095 MPa for 30 min, to obtain the one-component addition type liquid silicone rubber.

[0161] Comparative Example 7

[0162] The one-component addition type liquid silicone rubber provided in this comparative example, compared with Example 4, the silazane treating agent is composed of hexamethyldisilazane and tetramethyldisilazane, and the raw material composition is as follows:

[0163]

[0164]

[0165] The specific preparation method includes the following steps:

[0166] (1) Put the double-end vinyl silicone oil, end-side vinyl silicone oil, hexamethyl disilazane and tetramethyl disilazane into a kneader, put in the fumed silica in batches, knead at room temperature for 2 h, then heat up to 160°C and vacuumize to above -0.095 MPa, knead for 3 h to obtain the base material;

[0167] (2) Put the base material, end-side hydrogen-containing silicone oil and inhibitor into a planetary mixer, stir for 30 min after the completion of the feeding until the mixture is uniform;

[0168] (3) Put the platinum catalyst into the planetary mixer, stir and vacuumize to above -0.095 MPa for 30 min to obtain the one-component addition type liquid silicone rubber.

[0169] The one-component addition type liquid silicone rubbers prepared in the above Examples 1-5 and Comparative Examples 1-7 are respectively subjected to the following performance tests:

[0170] 1. Compression permanent deformation: determined according to GB / T 7759.1-2015 Rubber, vulcanized or thermoplastic - Determination of compression set - Part 1: at room temperature and at elevated temperature, with the test conditions being 177°C / 22 h and compression of 25%.

[0171] 2. Tensile strength: determined according to GB / T 528-2009 Rubber, vulcanized or thermoplastic - Determination of tensile stress-strain properties.

[0172] 3. Elongation at break: determined according to GB / T 528-2009 Rubber, vulcanized or thermoplastic - Determination of tensile stress-strain properties.

[0173] 4. Hardness: determined according to GB / T 531.1-2008 Rubber, vulcanized or thermoplastic - Determination of indentation hardness - Part 1: durometer method (Shore hardness).

[0174] The test results are as follows:

[0175]

[0176] As can be seen from the above table, the one-component addition type liquid silicone rubbers prepared in Examples 1-5 have not only lower compression permanent deformation, but also excellent tensile properties, because the high-viscosity end-side vinyl silicone oil, high-viscosity end-side hydrogen-containing silicone oil and fumed silica treated with hexamethyl disilazane, divinyl tetramethyl disilazane and tetramethyl disilazane modifier are used in combination, the compression permanent deformation is less than 15%, the tensile strength is about 5 MPa, the elongation at break is greater than 400%, and the hardness is about 45 Shore A.

[0177] Compared with Example 4: Comparative Example 1 only uses a common double-end vinyl silicone oil, and does not use a high-viscosity end-side vinyl silicone oil as the second polymer, and the compression permanent deformation of the one-component addition type liquid silicone rubber prepared thereby is 28%, which is obviously higher than that of Example 4, and the tensile strength is also obviously lower than that of Example 4; Comparative Example 2 only uses a hexamethyldisilazane modified fumed silica, and the compression permanent deformation of the one-component addition type liquid silicone rubber prepared thereby is 22%, which is obviously higher than that of Example 4, and the tensile strength is obviously lower than that of Example 4; Comparative Example 4 does not use a high-viscosity end-side vinyl silicone oil as the second polymer, but only uses a hexamethyldisilazane treated fumed silica, and uses a low-viscosity end-side hydrogen-containing silicone oil, and the compression permanent deformation thereof is the worst, reaching 35%, and the tensile performance is also the worst; Comparative Example 5 uses an end-side vinyl silicone oil with a smaller viscosity, and the compression permanent deformation of the one-component addition type liquid silicone rubber prepared thereby is 17%, the tensile strength decreases, and the elongation at break is poor; Comparative Example 6 uses a silazane treatment agent composed of only hexamethyldisilazane and divinyltetramethyldisilazane, and Comparative Example 7 uses a silazane treatment agent composed of only hexamethyldisilazane and tetramethyldisilazane, and the compression permanent deformation of the one-component addition type liquid silicone rubber prepared thereby is higher than that of Example 4, and the tensile strength is lower than that of Example 4; Compared with Example 5: Comparative Example 3 uses a low-viscosity end-side hydrogen-containing silicone oil, and the compression permanent deformation of the one-component addition type liquid silicone rubber prepared thereby reaches 18%, and the tensile strength and the elongation at break are also lower than those of Example 5.

[0178] The above-described examples only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A one-component addition type liquid silicone rubber, characterized by, Prepared from raw materials comprising the following components and a platinum catalyst in parts by weight: Both end vinyl silicone oil 100 parts End side vinyl silicone oil 1-7 parts Fumed silica 10-50 parts Silazane treating agent 0.5-5 parts End side hydrogen-containing silicone oil 1-5 parts Inhibitor 0.05-0.5 parts. The silazane treating agent is composed of hexamethyl disilazane, divinyl tetramethyl disilazane and tetramethyl disilazane; The viscosity of the end side vinyl silicone oil is 5000 mPa·s~150000 mPa·s; The viscosity of the end side hydrogen-containing silicone oil is 100 mPa·s~1000 mPa·s.

2. The one-component addition-cure liquid silicone rubber according to claim 1, characterized in that, Prepared from raw materials comprising the following components and a platinum catalyst in parts by weight: Both end vinyl silicone oil 100 parts End side vinyl silicone oil 3-5 parts Fumed silica 25-35 parts Silazane treating agent 2-3.5 parts End side hydrogen-containing silicone oil 1.3-3 parts Inhibitor 0.05-0.5 parts.

3. The one-component addition type liquid silicone rubber according to claim 1 or 2, characterized in that, The silazane treating agent is composed of hexamethyl disilazane, divinyl tetramethyl disilazane and tetramethyl disilazane in a mass ratio of 1.0:0.05~0.5:0.05~0.5; Preferably, the silazane treating agent is composed of hexamethyl disilazane, divinyl tetramethyl disilazane and tetramethyl disilazane in a mass ratio of 1.0:0.1~0.3:0.1~0.3; Preferably, the silazane treating agent is composed of hexamethyl disilazane, divinyl tetramethyl disilazane and tetramethyl disilazane in a mass ratio of 1.0:0.2~0.25:0.2~0.

25.

4. The one-component addition type liquid silicone rubber according to claim 1 or 2, characterized by, The viscosity of the end side vinyl silicone oil is 30000 mPa·s~100000 mPa·s, preferably 50000 mPa·s~80000 mPa·s; And / or, the vinyl content of the end side vinyl silicone oil is 1.0wt%~10wt%, preferably 2.0wt%~5.0wt%, more preferably 3.0wt%~4.0wt%.

5. The one-component addition type liquid silicone rubber according to claim 1 or 2, characterized by, The viscosity of the end side hydrogen-containing silicone oil is 150 mPa·s~500 mPa·s, preferably 200 mPa·s~300 mPa·s; And / or, the hydrogen content of the end side hydrogen-containing silicone oil is 0.5wt%~1.5wt%, preferably 0.6wt%~1.0wt%.

6. The one-component addition type liquid silicone rubber according to claim 1 or 2, characterized by, The viscosity of the both end vinyl silicone oil is 2000 mPa·s~50000 mPa·s, preferably 5000 mPa·s~30000 mPa·s, preferably 15000 mPa·s~25000 mPa·s.

7. The one-component addition type liquid silicone rubber according to claim 1 or 2, characterized by, The specific surface area of the fumed silica is 100 m 2 / g to 400 m 2 / g, preferably 300 m 2 / g to 350 m 2 / g.

8. The one-component addition type liquid silicone rubber according to claim 1 or 2, characterized by, The inhibitor is selected from one or more of 1-ethynyl-1-cyclohexanol, tetramethyl tetra-vinyl cyclo-tetra-siloxane, 2-methyl-3-butynyl-2-ol, 3-methyl-1-hexynyl-3-ol, 3,5-dimethyl-1-hexynyl-3-ol and 3-methyl-1-dodecyn-3-ol; And / or, the platinum catalyst is selected from one or more of chloroplatinic acid, chloroplatinic acid-isopropyl alcohol complex and Karstedt catalyst.

9. The one-component addition type liquid silicone rubber according to claim 1 or 2, characterized by, The content of the platinum catalyst is 0.5-10 ppm, preferably 2-6 ppm, by mass of platinum.

10. A process for the preparation of a one-component addition-cure liquid silicone rubber according to any one of claims 1 to 9, characterized in that The method comprises the following steps: The double-end vinyl silicone oil, end-side vinyl silicone oil and silazane treating agent are put into a kneader, the fumed silica is put in batches, and kneading is carried out at a temperature of 10-40°C for 1-3 hours, then the temperature is increased to 150-180°C and vacuum is applied, and kneading is carried out for 2-4 hours to obtain a base material; The base material, end-side hydrogen-containing silicone oil and inhibitor are uniformly mixed, and then the platinum catalyst is added and uniformly mixed under vacuum to obtain the one-component addition type liquid silicone rubber.

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