Organic silicon resin as well as preparation method and application thereof

Abstract

The invention relates to the technical field of organic silicon resin powder, in particular to organic silicon resin as well as a preparation method and application thereof. The organic silicon resin is prepared from the following raw materials in parts by mass: 25 to 36 parts of dimethyl dichlorosilane, 1 to 3 parts of tri (trichlorosilane) silane, 30 to 40 parts of 3-pyridine triethoxy silane and 4 to 8 parts of diphenyl dichlorosilane. Wherein a proper amount of dense crosslinking points are introduced into the organic silicon resin by utilizing tri (trichlorosilane) silane, so that the overall strength and toughness of the material are improved, and the material can better resist deformation and damage when being stressed; a pyridine group is introduced into a silicon resin molecular chain by utilizing 3-pyridyltriethoxysilane, so that the binding force of the silicon resin and a base material is enhanced, the compatibility of the silicon resin and other organic silicon resin is improved, and meanwhile, the thermal stability of the silicon resin is kept to the maximum extent.

Description

Technical Field

[0001] The present invention relates to the technical field of organic silicon resin powder, and in particular to an organic silicon resin and a preparation method and application thereof. Background Art

[0002] Powder coating is a new type of solvent-free 100% solid powder coating, which has the characteristics of being solvent-free, pollution-free, recyclable, environmentally friendly, energy and resource-saving, labor-reducing and high mechanical strength of the coating. Silicone resin powder has shown wide application potential in many fields due to its excellent heat resistance, weather resistance, electrical insulation and other properties. However, the use of silicone resin alone has problems such as high price, insufficient strength and toughness, and poor adhesion to the substrate. Therefore, it is often mixed with other organic resins to prepare coatings to make up for each other's shortcomings.

[0003] Simply mixing silicone resin with organic resin often does not improve the performance of powder coatings. This is because silicone resin often has poor compatibility with organic resins, and silicone overflows and accumulates on the surface, which is prone to obvious microphase separation. Microphase separation has a great impact on the hardness, stability and mechanical properties of the modified resin, resulting in poor overall performance of the final coating.

[0004] At present, the compatibility of silicone resin with other organic resins is mainly improved by reducing the amount of silicone resin added, adding silane coupling agent, or introducing reactive functional groups into the molecular chain of silicone resin. However, these operations will reduce the performance of silicone resin and fail to fully express its performance. How to further improve the strength, toughness and bonding strength with the substrate while maintaining the original excellent performance of silicone resin, while improving the compatibility with other silicone resins, has become a technical bottleneck that urgently needs to be broken through in current research. In response to this challenge, the present invention proposes an innovative method for preparing silicone resin, which aims to achieve a comprehensive improvement in material performance by optimizing the raw material composition and reaction conditions. Summary of the invention

[0005] In view of the shortcomings of the existing methods, the present invention provides an organic silicone resin, which has good adhesion to the substrate and compatibility with other organic resins, and maintains high heat resistance; the organic silicone resin is composed of the following raw materials in parts by mass:

[0006] 25-36 parts of dimethyldichlorosilane, 1-3 parts of tris(trichlorosilyl)silane, 30-40 parts of 3-pyridinetriethoxysilane, and 4-8 parts of diphenyldichlorosilane.

[0007] The preparation method of the above-mentioned silicone resin comprises the following steps:

[0008] Tri(trichlorosilyl)silane, 3-pyridinetriethoxysilane, dimethyldichlorosilane and diphenyldichlorosilane are mixed in proportion and added into a solvent for hydrolysis. After the hydrolysis, the polymer is washed with water, concentrated and desolventized to obtain a silicone resin polymer, which is then put into a twin-screw extruder for hot-melt extrusion, dried and crushed to obtain a silicone resin.

[0009] Furthermore, the hydrolysis temperature is 4 to 10° C. and the time is 5 to 8 hours.

[0010] Furthermore, the solvent consists of an organic solvent and water; the mass ratio of the organic solvent to water is 2 to 4:1; the amount of water used is 1 to 2 times the total mass of dimethyldichlorosilane, tri(trichlorosilyl)silane, 3-pyridinetriethoxysilane and diphenyldichlorosilane.

[0011] Furthermore, the organic solvent includes cyclohexanone, butanone, ethyl acetate or butyl ether.

[0012] The present invention also provides a powder coating comprising the above-mentioned silicone resin, wherein the powder coating is composed of the following parts by weight: silicone resin, epoxy resin, matting agent, curing agent, pigment and filler, and leveling agent;

[0013] The leveling agent includes PV88.

[0014] The matting agent includes TS100 matting powder.

[0015] The pigments and fillers include one or more of glass powder, talcum powder, silica powder, ferromanganese black, carbon black, and mica powder.

[0016] The curing agent includes one or more of VN-203 and phenolic curing agents.

[0017] The preparation method of the above-mentioned silicone resin powder coating comprises the following steps:

[0018] Add silicone resin, matting agent, curing agent, pigment filler and leveling agent into a mixing tank, stir at a speed of 400r / min for 30 minutes, and after stirring evenly, put them into a twin-screw extruder for melt extrusion, roll them into sheets on a flaking machine and cool them to room temperature, then send them into a grinder to grind them into powder, pass them through a sieve to adjust the particle size of the powder, and obtain a powder coating.

[0019] Furthermore, the heating conditions of the extruder are: the temperature of zone I is 90°C, and the temperature of zone II is 100°C.

[0020] Beneficial effects of the present invention:

[0021] The invention uses tri(trichlorosilyl)silane, dimethyldichlorosilane and 3-pyridyltriethoxysilane as raw materials to prepare an organic silicone resin, wherein the introduction of tri(trichlorosilyl)silane enables the organic silicone resin to have appropriate dense crosslinking points, forms a tighter and more complex network structure, helps to improve the overall strength and toughness of the material, and enables the material to better resist deformation and damage when subjected to force; 3-pyridyltriethoxysilane introduces a pyridine group into the silicone resin molecular chain, enhances the bonding force between the silicone resin and a substrate, improves its compatibility with other organic silicone resins, and simultaneously maintains its thermal stability to the maximum extent. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the embodiments.

[0023] Examples 1-6

[0024] Weigh tri(trichlorosilyl)silane, 3-pyridinetriethoxysilane, dimethyldichlorosilane and diphenyldichlorosilane according to the mass fractions in Table 1, mix and add into a solvent (the mass ratio of cyclohexanone to water is 3:1) for hydrolysis (4-10°C, 6h), wash with water after hydrolysis, concentrate and remove the solvent to obtain an organosilicon resin polymer, put into a twin-screw extruder for hot melt extrusion (90-100°C), dry and pulverize to obtain an organosilicon resin (particle size is 32-37μm);

[0025] The mass fractions of tri(trichlorosilyl)silane, 3-pyridinetriethoxysilane, dimethyldichlorosilane and diphenyldichlorosilane used are shown in Table 1 below.

[0026] Table 1

[0027]

[0028] Comparative Example 1

[0029] The difference between Comparative Example 1 and Example 2 is that tri(trichlorosilyl)silane is replaced by monomethyltrichlorosilane. The rest is Example 2.

[0030] Comparative Example 2

[0031] The difference between Comparative Example 2 and Example 2 is that the mass fraction of 3-pyridinetriethoxysilane is changed to 45 parts, and the rest is Example 2.

[0032] Comparative Example 3

[0033] 3 parts of monomethyltrichlorosilane, 30 parts of dimethyldichlorosilane, 40 parts of monophenyltrimethoxysilane and 6 parts of diphenyldichlorosilane are mixed, and then added into a solvent (the mass ratio of cyclohexanone to water is 3:1) for hydrolysis (4-10°C, 6h), and then washed with water after hydrolysis, concentrated and desolventized to obtain a silicone resin polymer, which is then put into a twin-screw extruder for hot-melt extrusion (90-100°C), dried and crushed to obtain a silicone resin (particle size is 32-37μm).

[0034] Comparative Example 4

[0035] The difference between Comparative Example 4 and Example 2 is that 3-pyridinetriethoxysilane is replaced by phenyltriethoxysilane, and the rest is Example 2.

[0036] Comparative Example 5

[0037] The difference between Comparative Example 5 and Example 2 is that the amount of tri(trichlorosilyl)silane added is changed to 4 parts, and the rest is Example 2.

[0038] Effect Example 1

[0039] The silicone resin prepared in the examples and comparative examples was mixed with a curing agent (VN-203 from Changzhou Jianuo Silicone Co., Ltd.) and a leveling agent (PV88, Dahai New Materials), and then electrostatically sprayed on a cold-rolled plate whose rust had reached Sa21 / 2, and then placed in an oven at 200°C for curing for 10 minutes. The coating thickness was about 60 μm, and the test samples were obtained. The performance test results are shown in Table 2.

[0040] Table 2

[0041]

[0042] From the data in Table 2, (1) comparing Example 2 with Comparative Example 1, the impact strength of Example 2 is better than that of Comparative Example 1, indicating that the introduction of tri(trichlorosilyl)silane allows the silicone resin to have appropriate dense cross-linking points, forming a coating with a tighter and more complex network structure, which helps to improve the overall strength and toughness of the material, so that it can better resist deformation and damage when subjected to force; (2) comparing Example 2 with Comparative Example 2 and Comparative Example 4, the adhesion of Example 2 is better than that of Comparative Example 4, indicating that the introduction of pyridine groups enhances the bonding strength between the silicone resin and the substrate, but too much 3-pyridinetriethoxysilane will lead to a weakening of the thermal stability of the coating.

[0043] Effect Example 2

[0044] The organosilicon resins prepared in Example 2, Comparative Example 1 and Comparative Example 4 were mixed with 604 epoxy resin, pigments, fillers, curing agents and leveling agents (the raw materials and their mass fractions are shown in Table 3), stirred at a speed of 400 r / min for 30 min, and after being uniformly stirred, put into a twin-screw extruder for melt extrusion. The heating conditions of the extruder were 90°C in zone I and 100°C in zone II. The mixture was extruded into a sheet rolling machine for sheeting, cooled to room temperature, and sent to a grinder for grinding. The grinding conditions were 8800-9000 r / min for the main mill and 6800-7000 r / min for the auxiliary mill. The particle size of the powder was adjusted to 32-37 μm through a sieve to obtain a powder coating.

[0045] Table 3

[0046]

[0047] The powder coating was electrostatically sprayed on the cold-rolled plate with rust removal reaching Sa21 / 2, and cured at 230°C for 10 minutes to obtain a coating with a thickness of about 50 μm. The coating performance test results are shown in Table 4 below.

[0048] Table 4

[0049]

[0050] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A silicone resin, characterized in that: The organosilicon resin is composed of the following raw materials in parts by mass: 25-36 parts of dimethyldichlorosilane, 1-3 parts of tris(trichlorosilyl)silane, 30-40 parts of 3-pyridinetriethoxysilane, and 4-8 parts of diphenyldichlorosilane.

2. The organosilicon resin according to claim 1, characterized in that The preparation method of the organic silicone resin comprises the following steps: Tri(trichlorosilyl)silane, 3-pyridinetriethoxysilane, dimethyldichlorosilane and diphenyldichlorosilane are mixed in proportion and added into a solvent for hydrolysis. After the hydrolysis, the polymer is washed with water, concentrated and desolventized to obtain a silicone resin polymer, which is then put into a twin-screw extruder for hot-melt extrusion, dried and crushed to obtain a silicone resin.

3. The organosilicon resin according to claim 2, characterized in that: The hydrolysis temperature is 4-10°C and the time is 5-8h.

4. The organosilicon resin according to claim 2, characterized in that: The solvent consists of an organic solvent and water; the mass ratio of the organic solvent to water is 2-4:1; the amount of water used is 1-2 times the total mass of dimethyldichlorosilane, tri(trichlorosilyl)silane, 3-pyridinetriethoxysilane and diphenyldichlorosilane.

5. The organosilicon resin according to claim 4, characterized in that: The organic solvent includes cyclohexanone, butanone, ethyl acetate or butyl ether.

6. A powder coating, characterized in that: The invention comprises the silicone resin as claimed in claim 1.

7. The powder coating according to claim 6, characterized in that The powder coating comprises the following raw materials: silicone resin, epoxy resin, matting agent, curing agent, pigment and filler, and leveling agent.

8. The powder coating according to claim 7, characterized in that The leveling agent includes PV88; The matting agent includes TS100 matting powder; The pigments and fillers include one or more of glass powder, talcum powder, silica powder, ferromanganese black, carbon black, and mica powder; The curing agent includes one or more of VN-203 and phenolic curing agents.

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