Tackifier, preparation method thereof and application of tackifier to silicone rubber

Abstract

The invention discloses a tackifier, a preparation method thereof and application of the tackifier to silicone rubber, and relates to the field of silicone rubber. Three phenyl silane coupling agents or more than three epoxy silane with different functionality degrees are used as raw materials, methanol or ethanol is used as a solvent, and the condensation reaction degree is controlled at the same time; the method comprises the following steps: by taking phenyl siloxane as a raw material and acidic cationic resin as a catalyst, carrying out partial cohydrolytic condensation at 20-80 DEG C, filtering to remove the cationic resin, and decompressing to remove a solvent and low volatile components, thereby obtaining the colorless and transparent phenyl siloxane oligomer tackifier with the polymerization degree of 3-6. The tackifier is suitable for a hydrosilylation silicone rubber system with adhesion requirements. The method is simple in process control and mild in reaction condition, and has better controllability and reproducibility. The method is expected to be widely applied to the fields of electronic and electric appliance industry, LED chip packaging, aerospace and the like.

Description

Technical Field

[0001] This invention relates to the field of silicone rubber technology, specifically to a tackifier, its preparation method, and its application in silicone rubber. Background Technology

[0002] Silicone materials are widely used in the electronics and aerospace industries due to their excellent electrical insulation and weather resistance. Silicone potting compounds are divided into two categories: condensation-type and addition-type, with addition-type being the dominant type on the market. With the rapid development of the electronics industry, the operating conditions of electronic devices are becoming increasingly demanding, and aerospace requirements are becoming increasingly stringent. Methyl silicone rubber has poor high-temperature resistance, and phenyl addition-type silicone rubber has poor adhesion to substrates such as metals, plastics, and PCBs. Under alternating high and low temperatures, they are prone to separation from the potted product, creating large gaps and significantly reducing protective performance, failing to meet the product's sealing requirements.

[0003] Research has explored the catalytic bonding of KH560 and KH570 to hydroxyl silicone oil using organotin catalysts. However, the organotin catalysts used in this study deactivate the platinum catalyst, significantly impacting the performance of the potting compound. Simultaneously, research has been conducted on the preparation methods of tackifiers for addition-type silicone thermally conductive potting compounds. However, these methods require the use of graphene, resulting in high production costs and requiring a synthesis temperature of 150°C, leading to significant energy consumption and failing to meet energy conservation and emission reduction requirements. Furthermore, the addition of methyl tackifiers to phenyl silicone rubber exhibits poor compatibility, affecting its adhesive properties.

[0004] Therefore, there is an urgent need to provide a tackifier that is low in cost, high in performance, and simple in preparation process. This tackifier is used in the preparation of two-component addition-cured phenyl silicone rubber, which enables the silicone rubber to have good adhesive properties and can well meet the sealing performance requirements of the product. Summary of the Invention

[0005] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a tackifier, its preparation method and its application in silicone rubber.

[0006] The technical solution of the present invention is as follows: A tackifier is made from the following raw materials in parts by weight: 100-200 parts epoxy silane, 30-100 parts phenyl silane coupling agent and 4-12 parts solid catalyst; The phenylsilane coupling agent includes at least three of the following: phenyltrimethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, phenyltriethoxysilane, and diphenyldiethoxysilane.

[0007] Preferably, the epoxy silane includes at least one of γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane.

[0008] Preferably, the solid catalyst is a strong acid cation exchange resin.

[0009] This invention also discloses a method for preparing a tackifier, comprising the following steps: A phenylsilane coupling agent and an epoxy silane are added to a solvent and a solid catalyst, and then partially co-hydrolyzed and condensed at 20-80°C. After filtering to remove the solid catalyst and removing the solvent and low volatiles under reduced pressure, a thickener is obtained.

[0010] Preferably, the solvent is methanol and / or ethanol.

[0011] The present invention also discloses a phenyl silicone rubber comprising component A and component B, wherein component A comprises phenyl hydrogen silicone oil, carbon black, a tackifier as described in any one of claims 1 or 2, or a tackifier prepared by the preparation method described in claims 3 or 4; component B comprises a platinum catalyst and divinyltetramethyldisiloxane; and components A and / or B each independently comprise at least one of ethylene phenyl silicone oil, methyl phenyl silicone oil, alumina, and aluminum hydroxide.

[0012] Preferably, the preparation method is as follows: mixing the raw materials of component A to obtain component A; mixing the raw materials of component B to obtain component B; the components A and B constitute the phenyl silicone rubber.

[0013] The beneficial effects of this invention are as follows: The tackifier of this invention contains phenyltrimethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, epoxysilane, KH-570, etc.; under the action of a solid acid catalyst; when the phenylsilane coupling agent and other coupling agents are used to synthesize a tackifier in a two-component phenyl addition-type silicone rubber, during the curing process of the silicone rubber, the acyloxysilane and epoxysilane on the molecular chain participate in the curing reaction with the hydroxyl groups of the phenylsilane coupling agent, and the acyl groups and epoxy groups in the acyloxysilane and epoxysilane form hydrogen bonds or covalent bonds with the hydroxyl groups on the surface of the substrate, so that the substrate and the silicone rubber are well bonded together, and the prepared silicone rubber has good adhesion and high temperature resistance, which can meet the sealing performance requirements of the product. Detailed Implementation

[0014] The embodiments of the present invention are described in detail below. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0015] Example 1 By weight, 60 parts of phenyltrimethoxysilane, 20 parts of diphenyldimethoxysilane, 30 parts of methylphenyldimethoxysilane, 15 parts of KH-560, 25 parts of KH-570, and 5 parts of solid acid catalyst (Lewatits-100 resin) were added to ethanol and mixed. Partial co-hydrolysis and condensation were carried out at 50°C. After filtering to remove the solid catalyst and removing the solvent and low volatile matter under reduced pressure, a colorless and transparent phenylsiloxane oligomer tackifier with a degree of polymerization of 3 to 6 was obtained, thus preparing the tackifier.

[0016] Example 2 By weight, 85 parts of phenyltrimethoxysilane, 30 parts of diphenyldimethoxysilane, 40 parts of methylphenyldimethoxysilane, 15 parts of KH-560, 30 parts of KH-570, and 8 parts of solid acid catalyst (Lewatits-100 resin) were added to ethanol and mixed. Partial co-hydrolysis and condensation were carried out at 50°C. After filtering to remove the solid catalyst and removing the solvent and low volatile matter under reduced pressure, a colorless and transparent phenylsiloxane oligomer tackifier with a degree of polymerization of 3 to 6 was obtained, thus preparing the tackifier.

[0017] Example 3 By weight, 55 parts of phenyltrimethoxysilane, 40 parts of diphenyldimethoxysilane, 30 parts of methylphenyldimethoxysilane, 10 parts of phenyltriethoxysilane, 20 parts of KH-560, 40 parts of KH-570, and 8 parts of solid acid catalyst (Lewatits-100 resin) were added to ethanol and mixed. Partial co-hydrolysis and condensation were carried out at 50°C. After filtering to remove the solid catalyst and removing the solvent and low volatile matter under reduced pressure, a colorless and transparent phenylsiloxane oligomer tackifier with a degree of polymerization of 3 to 6 was obtained, thus preparing the tackifier.

[0018] Example 4 By weight, 55 parts of phenyltrimethoxysilane, 40 parts of diphenyldimethoxysilane, 30 parts of methylphenyldimethoxysilane, 10 parts of phenyltriethoxysilane, 10 parts of diphenyldiethoxysilane, 20 parts of KH-560, 40 parts of KH-570, and 8 parts of solid acid catalyst (Lewatits-100 resin) were added to ethanol and mixed. Partial co-hydrolysis and condensation were carried out at 50°C. After filtering to remove the solid catalyst and removing the solvent and low volatile matter under reduced pressure, a colorless and transparent phenylsiloxane oligomer tackifier with a degree of polymerization of 3 to 6 was obtained, thus preparing the tackifier.

[0019] Comparative Example 1 Methyl tackifier (poly-α-methylstyrene resin) was used as Comparative Example 1.

[0020] Comparative Example 2 Methyl tackifier (xylene formaldehyde resin) was used as Comparative Example 2.

[0021] The tackifiers used in the examples and comparative examples were used to prepare silicone rubber according to the following method.

[0022] A silicone rubber comprises component A and component B; wherein component A comprises 6 wt% phenyl hydrogen silicone oil, 4 wt% carbon black, 2 wt% tackifier, and the balance being methylphenyl silicone oil; component B comprises 0.1% platinum catalyst, 0.05 wt% divinyltetramethyldisiloxane, and the balance being ethylenephenyl silicone oil. The preparation involves mixing and reacting components A and B at 130°C for 3 hours.

[0023] The silicone rubber samples prepared above were subjected to aging tests. Their shear strength and elongation at break were tested before and after aging. The test results are shown in Table 1.

[0024] Table 1 Performance test results of the examples and comparative examples

[0025] As shown in the table above, the shear strength and elongation of the phenyl silicone adhesive cured with the tackifier used in this invention are significantly higher than those of the adhesive cured with methyl silicone adhesive. After high-temperature aging, the properties of the phenyl silicone adhesive cured with the tackifier do not change significantly, while those of the methyl silicone adhesive cured with the tackifier decrease significantly, indicating that the high-temperature resistance of the phenyl silicone adhesive cured with the tackifier is significantly better than that of the silicone adhesive cured with the methyl tackifier.

[0026] The embodiments described above are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of the present invention.

Claims

1. A thickener, characterized in that, It is made from the following raw materials in parts by weight: 100-200 parts epoxy silane, 30-100 parts phenyl silane coupling agent and 4-12 parts solid catalyst; The phenylsilane coupling agent includes at least three of the following: phenyltrimethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, phenyltriethoxysilane, and diphenyldiethoxysilane.

2. The thickener according to claim 1, characterized in that, The epoxy silane includes at least one of γ-glycidyl etheroxypropyltrimethoxysilane, γ-glycidyl etheroxypropyltriethoxysilane, 3-glycidyl etheroxypropylmethyldimethoxysilane, and 3-glycidyl etheroxypropylmethyldiethoxysilane.

3. The thickener according to claim 1, characterized in that, The solid catalyst is a strong acid cation exchange resin.

4. A method for preparing the thickener as described in any one of claims 1-3, characterized in that, Includes the following steps: A phenylsilane coupling agent and an epoxy silane are added to a solvent and a solid catalyst, and then partially co-hydrolyzed and condensed at 20-80°C. After filtering to remove the solid catalyst and removing the solvent and low volatiles under reduced pressure, a thickener is obtained.

5. The method for preparing a thickener according to claim 4, characterized in that, The solvent is methanol and / or ethanol.

6. A phenyl silicone rubber, characterized in that, It includes component A and component B, wherein component A includes phenyl hydrogen silicone oil, carbon black, the tackifier according to any one of claims 1 or 2, or the tackifier prepared by the preparation method according to claims 3 or 4; component B includes platinum catalyst and divinyltetramethyldisiloxane; and component A and / or component B each independently include at least one of ethylene phenyl silicone oil, methyl phenyl silicone oil, alumina, and aluminum hydroxide.

7. The phenyl silicone rubber according to claim 6, characterized in that, The preparation method is as follows: the raw materials of component A are mixed to obtain component A; the raw materials of component B are mixed to obtain component B; component A and component B constitute the phenyl silicone rubber.

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