A hardening coating composition for MS resin

Abstract

The application provides a hardening coating composition for MS resin, and relates to the technical field of hardening coating. The hardening coating composition for MS resin comprises, by weight, 100 parts of silane hydrolysate, 0.3-10 parts of a di-end epoxy group polyether polysiloxane copolymer and 0-2 parts of an accelerator, wherein the silane hydrolysate contains amino groups. The hardening coating composition can be cured by heating, and has good and durable adhesion to the MS resin after curing.

Description

Technical Field

[0001] This invention belongs to the field of hardening coating technology and relates to a hardening coating composition for MS resin. Background Technology

[0002] MS resin is a styrene (St)-methyl methacrylate (MMA) copolymer resin. In addition to the good processing fluidity and low moisture absorption of polystyrene (PS), it also has the weather resistance and excellent optical properties of polymethyl methacrylate (PMMA). MS resin has a refractive index of 1.56, and its transparency is similar to that of PS, with a light transmittance of up to 92%. It is a transparent, non-toxic thermoplastic.

[0003] MS resin has better flexibility than PMMA but lower hardness, making it more prone to surface scratches and wear during use, especially in lens applications where high scratch resistance is required. Increasing the hardness of resin lenses is a primary technical solution for scratch resistance, such as coating the surface with a silicone-inorganic silicon hybrid hardening coating, which is already widely used in polycarbonate (PC) lenses. However, compared to PC resin, MS resin has lower polarity. Although surface treatments (such as ozone oxidation or corona treatment) are applied before hardening coatings to increase polarity and structures containing silanol or alkoxysilane groups are used to improve adhesion, the resin surface gradually reverts to its low polarity over time, causing the hardening coating to gradually fail.

[0004] Document 1 discloses a composition for hard coating comprising: (A) urethane (meth)acrylate, (B) polyfunctional (meth)acrylate, (C) a polymer obtained by polymerizing a fluorinated (meth)acrylate, and (D) metal oxide microparticles. However, it does not disclose whether the adhesion of the hard coating is durable.

[0005] Therefore, further research is needed on hardening coatings for MS resin to achieve good adhesion and durability of the hardened coating, as well as good overall performance.

[0006] Reference 1: CN104812853A. Summary of the Invention

[0007] To address the aforementioned technical problems, the present invention provides a hardening coating composition for MS resin.

[0008] The technical solution of the present invention is as follows:

[0009] A hardening coating composition for MS resin, comprising, by weight, 100 parts of silane hydrolysate, 0.3-10 parts of bi-epoxy-terminated polyether polysiloxane copolymer, and 0-2 parts of accelerator;

[0010] The silane hydrolysate is obtained by hydrolysis and condensation of the silane compound shown in formula (1);

[0011] R 1 a R 2 b R 3 c Si(OR 4 ) 4-a-b-c (1)

[0012] Among them, R 1 Selected from C1-C24 alkyl or substituted C2-C36 alkyl, R 2 Selected from polyether segment structures, R 3 Selected from amino-substituted C2-C8 alkyl groups, R 4 Selected from H or C1-C4 alkyl groups, a≥0, b≥0, c≥0, 0 <a+b+c<4。

[0013] Preferably, the values ​​of a, b, and c satisfy: 0.05 ≤ b / (a+b+c) ≤ 0.2.

[0014] Preferably, the values ​​of a, b, and c satisfy: 0.03≤c / (a+b+c)≤0.12.

[0015] Preferably, the dual-terminated epoxy polyether polysiloxane copolymer is a block copolymer of polyether and polysiloxane.

[0016] More preferably, the molar ratio of the polyether to the polysiloxane is 1:2 to 2:1.

[0017] More preferably, the structure of the polyether is shown in formula (2).

[0018] -(EO) x (PO) y -(2)

[0019] Wherein, EO represents polyethylene oxide segment, PO represents polyethylene oxide segment, x>0, y≥0, and x / (x+y)≥0.4.

[0020] Preferably, the promoter is selected from imidazole compounds.

[0021] Preferably, the raw material components further contain 1-30 parts of nano-sized inorganic oxides.

[0022] More preferably, the surface of the nanoscale inorganic oxide is chemically bonded with organic groups, wherein the organic groups contain epoxy or amino groups.

[0023] More preferably, the epoxy group or the amino group accounts for no more than 50% of the molar percentage of the organic group.

[0024] The beneficial effects of this invention are:

[0025] (1) In view of the low polarity of MS resin, the present invention uses a double-ended epoxy polyether polysiloxane copolymer as an interface wetting agent to improve the wetting performance of the hardening coating composition on the surface of MS resin and promote the improvement of the bonding force between the hardening coating and MS resin.

[0026] (2) The double-epoxy-terminated polyether polysiloxane copolymer added in this invention can also participate in the curing of the hardening coating composition, so that the double-epoxy-terminated polyether polysiloxane copolymer can be stably and firmly distributed in the interior and interface of the hardening coating, playing a long-term wetting role and improving the adhesion of the hardening coating.

[0027] It is durable, and the double-ended epoxy polyether polysiloxane copolymer can participate in the cross-linking reaction of the coating, avoiding adverse effects on light transmittance.

[0028] (3) Nanoscale inorganic oxides can also be added to the hardening coating composition of the present invention to further improve the coating hardness, and by modifying its surface, it can participate in the cross-linking and curing of the hardening coating to improve the stability of performance. Detailed Implementation

[0029] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0030] In order to improve the adhesion and adhesion durability of the hardening coating on the surface of MS resin, the present invention proposes a hardening coating composition for MS resin, wherein the raw material components, by weight, include 100 parts of silane hydrolysate, 0.3-10 parts of double-terminated epoxy polyether polysiloxane copolymer and 0-2 parts of accelerator.

[0031] The above-mentioned silane hydrolysate is obtained by hydrolysis and condensation of the silane compound shown in formula (1);

[0032] R 1 a R 2 b R 3 c Si(OR 4 ) 4-a-b-c (1)

[0033] Among them, R 1 Selected from C1-C24 alkyl or substituted C2-C36 alkyl, R 2 Selected from polyether segment structures, R 3 Selected from amino-substituted C2-C8 alkyl groups, R 4Selected from H or C1-C4 alkyl groups, a≥0, b≥0, c≥0, 0 <a+b+c<4。

[0034] In order to harden MS resin, this invention uses silane hydrolysate as the main film-forming material, which can crosslink to form an organosilicon-inorganic silicon hybrid hardened coating with high light transmittance and hardness. For the problem of low surface polarity of MS resin and poor coating adhesion, this invention adds a double-terminated epoxy polyether polysiloxane copolymer to the silane hydrolysate, which has the following effects: (1) The polyether polysiloxane copolymer can effectively reduce the interfacial tension between the coating composition and MS resin. The coating composition has good wettability on the surface of MS resin, promotes the formation of more reaction points between the silane hydrolysate and MS resin, and improves the bonding force and adhesion; (2) The end groups of the polyether polysiloxane copolymer are epoxy groups, which can react with the amino groups in the silane hydrolysate and form an integral part with the coating from the microscopic level. The polyether polysiloxane copolymer between the coating and MS resin interface is also fixed and plays a continuous and long-term wetting role, so that the hardened coating has durable adhesion to MS resin.

[0035] The weight percentage of the di-terminated epoxy polyether polysiloxane copolymer can be further 1-10 parts, for example, any value among 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc., without any particular limitation.

[0036] In a preferred embodiment of the present invention, the values ​​of a, b, and c satisfy: 0.05 ≤ b / (a+b+c) ≤ 0.2, where the value of b / (a+b+c) represents R. 2 The molar content, for example, the value of b / (a+b+c) can be any value among 0.05, 0.08, 0.1, 0.12, 0.15, 0.18, 0.2, etc., without particular limitation. More preferably, the values ​​of a, b, and c satisfy: 0.08 ≤ b / (a+b+c) ≤ 0.15. In this invention, R 2 There are no particular restrictions on its structure; for example, it could be -CH2CH2O(CH2CH2O). p (CH2CHCH3O) q R 4 Where p≥0, q≥0, p+q≥3, R 4 It can be H or C1-C8 alkyl. In this invention, R can be adjusted... 2 The structure and molar content of silane hydrolysates can be adjusted to modify their polarity or affinity for water, making them suitable for use in oily systems, aqueous systems, or mixed systems of water and polar solvents.

[0037] For the above silane hydrolysates, R 3The function is to fix the polyether polysiloxane copolymer in the coating by reacting amino and epoxy groups, and it mainly plays two roles: (1) to provide a durable wetting effect on the MS resin interface; (2) to toughen the coating by utilizing the flexible structure of the polyether polysiloxane. In the preferred embodiment of the present invention, the values ​​of a, b, and c satisfy: 0.03≤c / (a+b+c)≤0.12. The value of c / (a+b+c) represents R 3 The molar content, for example, the value of c / (a+b+c) can be any value from 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, etc., without any particular limitation. More preferably, the values ​​of a, b, and c satisfy: 0.05 ≤ c / (a+b+c) ≤ 0.1. In this invention, R 3 There are no particular restrictions on the structure; the amino group can be a primary amino group or a secondary amino group. For example, R 3 The structure can be -(CH2)3NH2, -(CH2)3NHCH2CH2NH2, -(CH2)3NHCH3, -(CH2)3NHCH2CH3, etc.

[0038] In a preferred embodiment of the present invention, the dual-epoxy-terminated polyether polysiloxane copolymer is a block copolymer of polyether and polysiloxane. The block copolymer of polyether and polysiloxane has a good effect on reducing interfacial tension, which can improve the wettability of the hardening coating composition to MS resin and promote the bonding force between the silane hydrolysate and the MS resin. Furthermore, by utilizing the reaction between the terminal epoxy groups of the block copolymer and the amino groups in the silane hydrolysate, the block copolymer at the interface between the coating and the MS resin can remain stably and continuously wet the MS resin interface, thus ensuring the long-lasting adhesion of the hardening coating to the MS resin. In this invention, polydimethylsiloxane is used as an example of polysiloxane, PE represents polyether, and PDMS represents polydimethylsiloxane. The structure of the block copolymer can be PE-b-PDMS, PE-b-PDMS-b-PE, PDMS-b-PE-b-PDMS, or (PE-b-PDMS). nThe preparation methods of block copolymers are well known to those skilled in the art. For example, they can be obtained by hydrosilylation reaction of terminal epoxy-terminated allyl polyethers with dimethyl silanes (DSM-2), or by hydrosilylation reaction of terminal epoxy-terminated allyl polyethers with monomethyl silanes (DSM-2), or by ring-opening reaction of DSM-2 with monoamino polydimethyl silanes (DSM-2), or by ring-opening reaction of DSM-2 with DSM-2, or by ring-opening reaction of DSM-2 with DSM-2, or by ring-opening reaction of DSM-2 with DSM-2, or by ring-opening reaction of DSM-2 with DSM-2, or by ring-opening reaction of DSM-2 with DSM-2, etc. In this invention, the structure of the epoxy group is not particularly limited. For example, the structure of the terminal epoxy-terminated allyl polyether can be (CH2CHO)CH2O-PE-CH2CH=CH2.

[0039] Furthermore, in this invention, the dual-epoxy-terminated polyether polysiloxane copolymer can be composed of copolymers with different number-average molecular weights, which further promotes the enhancement of the flexibility and adhesion of the hardened coating. For example, the dual-epoxy-terminated polyether polysiloxane copolymer is composed of a copolymer with a lower number-average molecular weight (first copolymer) and a copolymer with a higher number-average molecular weight (second copolymer). The number-average molecular weights of the first copolymer and the second copolymer can differ by more than 1000, or the number-average molecular weight of the second copolymer can be twice or more than that of the first copolymer. The weight ratio of the first copolymer to the second copolymer can be 1:1 to 4:1.

[0040] In this invention, there are no particular restrictions on the polysiloxane structure, and the structure can be as shown in formula (3).

[0041] -(CH3)2SiO(SiOCH3CH3) m (SiOCH3R 5 ) n Si(CH3)2-, where R 5 It can be methyl, phenyl, propyl, trifluoropropyl, etc., and the values ​​of m and n can satisfy: m > 0, n ≥ 0, 5 ≤ m + n ≤ 100. When R 5 It is a phenyl group and R 5 When the content of is high, the polysiloxane structure has a high refractive index.

[0042] In a more preferred embodiment of the present invention, the molar ratio of polyether to polysiloxane is 1:2-2:1. For example, the molar ratio of polyether to polysiloxane can be 1:2, 1:1.5, 1:1, 1.5:1, 2:1, etc. Different molar ratios can be selected according to the specific raw materials and / or reaction methods of polyether and polysiloxane. For example, a hydrosilylation reaction can be carried out between epoxy-terminated allyl polyether and mono-terminated dimethylsiloxane, and the molar ratio of polyether to polysiloxane can be 1:1. Alternatively, a hydrosilylation reaction can be carried out between epoxy-terminated allyl polyether and dimethylsiloxane, and the molar ratio of polyether to polysiloxane can be 2:1.

[0043] In a more preferred embodiment of the present invention, the polyether has the structure shown in formula (2).

[0044] -(EO) x (PO) y -(2)

[0045] Where EO represents polyethylene oxide segments, PO represents polypropylene oxide segments, x>0, y≥0, and x / (x+y)≥0.4. The polyether can be composed of polyethylene oxide segments and / or polypropylene oxide segments. Polyethylene oxide segments have higher polarity than polypropylene oxide segments, improving the surface activity and wetting properties of the doubly epoxy-terminated polyether polysiloxane copolymer. The value of x / (x+y) represents the molar content of polyethylene oxide segments in the polyether structure. For example, the value of x / (x+y) can be any value from 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, etc., without any particular restriction. Furthermore, the value of x+y can satisfy: 0.5≤x / (x+y)≤0.8.

[0046] In a preferred embodiment of the present invention, the accelerator is selected from imidazole compounds. Under the action of the accelerator, the epoxide and amino groups can react more quickly and completely, and the reaction temperature can be lower, such as room temperature to 80°C. For example, the imidazole compound can be 2-methylimidazole, etc.

[0047] In a preferred embodiment of the present invention, the raw material components further contain 1-30 parts of nano-sized inorganic oxides. Adding nano-sized inorganic oxides to the hardening coating can further improve the coating's hardness. The average particle size of the nano-sized inorganic oxides can be 1-80 nm, which is lower than the wavelength of light, therefore having little or no effect on the coating's transmittance. For example, the nano-sized inorganic oxides can be nano-SiO2, nano-TiO2, nano-ZrO2, nano-Al2O3, nano-ZnO, nano-CeO2, etc. The nano-sized inorganic oxides can be obtained from corresponding sols, such as preparing nano-SiO2 from silica sol. For example, the number of parts of the nano-sized inorganic oxides can be any value from 1 part, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, etc., without particular limitation. More preferably, the number of parts of the nano-sized inorganic oxides can be 5-25 parts, or further, 5-20 parts. In this invention, nanoscale inorganic oxides can be directly used as aqueous dispersions of nanoscale inorganic oxides, such as nanocolloidal silicon Levasil R900. When using them, it is necessary to convert them according to the solid content of the aqueous dispersion.

[0048] In a more preferred embodiment of the present invention, organic groups are chemically bonded to the surface of the nano-sized inorganic oxides, and these organic groups contain epoxy or amino groups. The chemical bonding of organic groups to the surface of the nano-sized inorganic oxides can improve their compatibility and dispersibility in the coating composition, avoiding the impact of uneven dispersion on the coating's light transmittance, hardness, etc. The presence of epoxy or amino groups in the organic groups can participate in the cross-linking and curing reaction of the coating, allowing the nano-sized inorganic oxides to be firmly dispersed in the coating through chemical bonding. Furthermore, the enhanced bonding force of the nano-sized inorganic oxides in the coating can promote the improvement of coating performance, such as impact resistance and hardness.

[0049] In this invention, the chemical bonding of organic groups to the surface of nanoscale inorganic oxides is well known to those skilled in the art and can be achieved in various ways, such as using silane coupling agents. Examples of silane coupling agents include methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, butyltrimethoxysilane, n-octyltrimethoxysilane, lauryltrimethoxysilane, 3-aminopropyltrimethoxysilane, β-aminoethyl-γ-aminopropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, and 3-glycidyl etheroxypropyltrimethoxysilane.

[0050] In a further preferred embodiment of the present invention, the molar percentage of epoxy or amino groups in the organic groups does not exceed 50%. A higher content of epoxy or amino groups in the organic groups may lead to excessively high crosslinking density in the coating, which could reduce the coating's adhesion and impact resistance. For example, the molar percentage of epoxy or amino groups in the organic groups can be any value from 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, etc., without particular limitation. The molar content of epoxy or amino groups in the organic groups can be determined according to the molar ratio of the types of silane coupling agents used. For example, methyltrimethoxysilane and 3-glycidyl etheroxypropyltrimethoxysilane can be used to modify the surface of nanoscale inorganic oxides in molar ratios of 4:1, 3:2, 5:1, 2:1, 1:1, etc.

[0051] The preparation method of the hardening coating composition of the present invention is not particularly limited; the raw material components can be mixed and dispersed evenly. Depending on the needs of application, the raw material components of the hardening coating composition may also include solvents, such as water and / or organic solvents. Organic solvents may include: alcohol solvents, such as anhydrous ethanol, isopropanol, etc.; ether solvents, such as BCS, DPM, etc.; ketone solvents, such as methyl ethyl ketone, cyclohexanone, etc.; ester solvents, such as ethyl acetate, butyl acetate, etc. The hardening coating composition of the present invention can be applied to the surface of MS resin by spraying, rolling, dipping, or curtain coating, and the coating thickness can be 0.1 μm-20 μm.

[0052] The technical solution of the present invention will be further described and illustrated below with reference to various embodiments. Unless otherwise specified, the parts mentioned in the following embodiments are parts by weight.

[0053] The first copolymer 1-1 is obtained by hydrosilylation reaction of terminal epoxy-terminated allyl polyether (x = 6.3, y = 2.8 in formula (2) above) and dimethylsiloxane (m = 20.7, n = 0 in formula (3) above) in a molar ratio of 2:1.

[0054] The first copolymer 1-2 is obtained by hydrosilylation reaction of terminal epoxy-terminated allyl polyether (x = 7.5, y = 6.1 in formula (2) above) and single-terminated dimethylsiloxane (m = 15.8, n = 0 in formula (3) above) in a molar ratio of 1:1.

[0055] The second copolymer 2-1 is obtained by hydrosilylation reaction of terminal epoxy-terminated allyl polyether (x = 15.1, y = 8.2 in formula (2) above) and dimethylsiloxane (m = 37.4, n = 0 in formula (3) above) in a molar ratio of 2:1.

[0056] Example 1

[0057] The silane compound is composed of butyltrimethoxysilane, polyethylene glycol (200)trimethoxysilylpropyl ether, methyltrimethoxysilane and 3-aminopropyltrimethoxysilane in a molar ratio of 40:10:43:7.

[0058] Preparation of silane hydrolysate: 100 parts of silane compound were added to a reaction vessel, along with 80 parts of anhydrous ethanol and 50 parts of purified water. The mixture was stirred until homogeneous, and then 3 parts of acetic acid were added. The mixture was stirred at room temperature for 3 hours. The temperature was raised to 60-70℃ and the low-boiling substances were removed under reduced pressure to obtain the silane hydrolysate.

[0059] The raw material components of the hardening coating composition consist of 100 parts of the above-mentioned silane hydrolysate, 5 parts of the above-mentioned first copolymer 1-1, 1 part of 2-methylimidazole, 30 parts of isopropanol, and 50 parts of butyl acetate. The silane hydrolysate, first copolymer 1-1, isopropanol, and butyl acetate are mixed and stirred until homogeneous. Then, 2-methylimidazole is added and stirred until homogeneous to obtain the hardening coating composition.

[0060] Example 2

[0061] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the first copolymer 1-1 is replaced with an equal weight of the second copolymer 2-1. The remaining steps remain unchanged.

[0062] Example 3

[0063] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the first copolymer 1-1 is replaced with an equal weight of the first copolymer 1-1 and the second copolymer 2-1 in a weight ratio of 1:1. The remaining steps remain unchanged.

[0064] Example 4

[0065] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the first copolymer 1-1 is replaced with an equal weight of the first copolymer 1-2 and the second copolymer 2-1 in a weight ratio of 3:1. The remaining steps remain unchanged.

[0066] Example 5

[0067] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the first copolymer 1-1 was changed from 5 parts to 1 part. The remaining steps remain unchanged.

[0068] Example 6

[0069] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the first copolymer 1-1 was changed from 5 parts to 10 parts. The remaining steps remain unchanged.

[0070] Comparative Example 1

[0071] The difference between this comparative example and Example 1 is that in Example 1, the first copolymer 1-1 was replaced with an equal weight of wetting agent Tego 4100. The remaining steps remained unchanged.

[0072] Comparative Example 2

[0073] The difference between this comparative example and Example 1 is that in Example 1, the first copolymer 1-1 was replaced with 0.6 parts of wetting agent Tego 4100. The remaining steps remained unchanged.

[0074] Comparative Example 3

[0075] The difference between this comparative example and Example 1 is that the first copolymer 1-1 was not added in Example 1. The remaining steps remain unchanged.

[0076] Comparative Example 4

[0077] The difference between this comparative example and Example 1 is that in Example 1, the first copolymer 1-1 was replaced with an equal weight of polyether-modified polysiloxane. The remaining steps remained unchanged.

[0078] Polyether-modified polysiloxanes are prepared by the following method: terminal allyl polyether CH2=CHCH2O(CH2CH2O) 6.5 (CH2CHCH3O) 2.2 CH3 is obtained by hydrosilylation reaction with dimethylsiloxane (m = 20.7, n = 0 in formula (3) above) at a molar ratio of 2:1.

[0079] Example 7

[0080] The silane compound is composed of tetraethyl orthosilicate, butyltrimethoxysilane, polyethylene glycol (400)trimethoxysilylpropyl ether, methyltrimethoxysilane and N-methyl-3-aminopropyltrimethoxysilane in a molar ratio of 15:18:12:40:15.

[0081] Preparation of silane hydrolysate: 100 parts of silane compound were added to a reaction vessel, along with 80 parts of anhydrous ethanol and 50 parts of purified water. The mixture was stirred until homogeneous, and then 3 parts of acetic acid were added. The mixture was stirred at room temperature for 4 hours, and then heated to 60-70℃ to reduce the boiling point under reduced pressure to obtain the silane hydrolysate.

[0082] The raw material components of the hardening coating composition consist of 100 parts of the above-mentioned silane hydrolysate, 6 parts of the above-mentioned first copolymer 1-2, 1 part of 2-methylimidazole, 50 parts of isopropanol, and 50 parts of butyl acetate. The hardening coating composition is obtained by mixing the silane hydrolysate, the first copolymer 1-2, 2-methylimidazole, isopropanol, and butyl acetate and stirring until homogeneous.

[0083] Example 8

[0084] The difference between this embodiment and Embodiment 7 is that in Embodiment 7, 30 parts of nano-SiO2 aqueous dispersion (nano-colloidal silica Levasil R900) were added to the raw material components of the hardening coating composition. The remaining steps remained unchanged.

[0085] Example 9

[0086] The difference between this embodiment and Embodiment 8 is that in Embodiment 8, 10.2 parts by weight of amino-modified nano-SiO2 were replaced in the nano-SiO2 aqueous dispersion. The remaining steps remained unchanged.

[0087] The preparation method of amino-modified nano-SiO2 is as follows: 50 parts of the nano-SiO2 aqueous dispersion from Example 8 are dispersed in 100 parts of anhydrous ethanol, 3 parts of a silane coupling agent composed of methyltrimethoxysilane and N-methyl-3-aminopropyltrimethoxysilane in a molar ratio of 4:1 are added, the mixture is stirred evenly, and then 10 parts of water are added. The mixture is stirred at room temperature for 3 hours, the solid is collected, the solid is washed twice with anhydrous ethanol, and dried overnight in an oven at 60°C to obtain amino-modified nano-SiO2.

[0088] Example 10

[0089] The difference between this embodiment and Example 9 is that in Example 9, the amount of amino-modified nano-SiO2 was adjusted from 10.2 parts to 20 parts. The remaining steps remain unchanged.

[0090] Performance testing

[0091] The hardening coating compositions of Examples 1-10 and Comparative Examples 1-4 were applied to a clean MS resin surface (the MS resin surface was not treated with corona or the like) by dip coating process. After dip coating, the coatings were directly transferred to an oven at 80°C and heated for 3 hours before being removed.

[0092] Adhesion: Tested according to the method of GB / T9286-1998.

[0093] Hardness: Tested according to GB / T 6739-2006.

[0094] Impact resistance: Tested according to the method of GB / T22374-2018.6.3.10, the highest impact energy that does not cause cracks in the coating.

[0095] Transmittance: The transmittance in the visible light region was measured using a UV-Vis spectrophotometer according to the method in GB / T2410-2008.

[0096] Thermal shock performance: 60℃×2h±20℃×2h constitutes one thermal shock cycle. After 50 thermal shock cycles, the coating adhesion is tested after being placed at room temperature for 24h.

[0097] Salt spray performance test: 5% sodium chloride, neutral saline, 37℃, test for 168 hours, then take out, rinse with clean water and dry, and then place at room temperature for 24 hours before testing the adhesion of the coating.

[0098] The results are shown in Table 1 below.

[0099] Table 1

[0100]

[0101] As can be seen from the data results in Table 1 above, the hardening coating composition of the present invention is used for hardening coating of MS resin. The coating has good adhesion, high light transmittance, and good impact resistance. After cold and hot shock tests and salt spray tests, it still has good adhesion.

[0102] As described above, the basic principles, main features, and advantages of the present invention have been shown and described. Those skilled in the art should understand that the present invention is not limited to the above embodiments, which are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the patent and the description should still fall within the scope of the present invention. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A stiffening coating composition for MS resin, characterized by, The raw material components comprise 100 parts of a silane hydrolysate, 0.3-10 parts of a double-end epoxy polyether polysiloxane copolymer and 0-2 parts of an accelerator by weight fraction; The silane hydrolysate silane compound is obtained by hydrolytic condensation; The silane compound is composed of butyl trimethoxysilane, polyethylene glycol trimethoxysilane propyl ether, methyl trimethoxysilane and 3-aminopropyl trimethoxysilane in a molar ratio of 40:10:43:7, and the molecular weight of the polyethylene glycol in the polyethylene glycol trimethoxysilane propyl ether is 200; or, the silane compound is composed of tetraethyl orthosilicate, butyl trimethoxysilane, polyethylene glycol trimethoxysilane propyl ether, methyl trimethoxysilane and N-methyl-3-aminopropyl trimethoxysilane in a molar ratio of 15:18:12:40:15, and the molecular weight of the polyethylene glycol in the polyethylene glycol trimethoxysilane propyl ether is 400.

2. The stiffening coating composition for MS resin according to claim 1, characterized by, The double-end epoxy polyether polysiloxane copolymer is a block copolymer of polyether and polysiloxane.

3. The stiffening coating composition for MS resin according to claim 2, characterized by, The molar ratio of the polyether and the polysiloxane is 1:2-2:

1.

4. The stiffening coating composition for MS resin according to claim 2, characterized by, The structure of the polyether is shown in the following formula (2), -(EO) x (PO) y - (2) wherein, EO represents a polyethylene oxide chain segment, PO represents a polypropylene oxide chain segment, x>0, y≥0, x / (x+y)≥0.

4.

5. The stiffening coating composition for MS resin according to claim 1, characterized by, The accelerator is selected from imidazole compounds.

6. The stiffening coating composition for MS resin according to claim 1, characterized by, The raw material components further contain 1-30 parts of nano-sized inorganic oxides.

7. The stiffening coating composition for MS resin according to claim 6, characterized by, The nano-sized inorganic oxides have organic groups chemically bonded on the surface, and the organic groups contain epoxy groups or amino groups.

8. The stiffening coating composition for MS resin according to claim 7, characterized by, The molar proportion of the epoxy groups or the amino groups in the organic groups is not more than 50%. The raw material components comprise 100 parts of a silane hydrolysate, 0.3-10 parts of a double-end epoxy polyether polysiloxane copolymer and 0-2 parts of an accelerator by weight fraction; The silane hydrolysate silane compound is obtained by hydrolytic condensation; The silane compound is composed of butyl trimethoxysilane, polyethylene glycol trimethoxysilane propyl ether, methyl trimethoxysilane and 3-aminopropyl trimethoxysilane in a molar ratio of 40:10:43:7, and the molecular weight of the polyethylene glycol in the polyethylene glycol trimethoxysilane propyl ether is 200; or, the silane compound is composed of tetraethyl orthosilicate, butyl trimethoxysilane, polyethylene glycol trimethoxysilane propyl ether, methyl trimethoxysilane and N-methyl-3-aminopropyl trimethoxysilane in a molar ratio of 15:18:12:40:15, and the molecular weight of the polyethylene glycol in the polyethylene glycol trimethoxysilane propyl ether is 400. The double-end epoxy polyether polysiloxane copolymer is a block copolymer of polyether and polysiloxane. The molar ratio of the polyether and the polysiloxane is 1:2-2:

1. The structure of the polyether is shown in the following formula (2), wherein, EO represents a polyethylene oxide chain segment, PO represents a polypropylene oxide chain segment, x>0, y≥0, x / (x+y)≥0.

4. The accelerator is selected from imidazole compounds. The raw material components further contain 1-30 parts of nano-sized inorganic oxides. The nano-sized inorganic oxides have organic groups chemically bonded on the surface, and the organic groups contain epoxy groups or amino groups. The molar proportion of the epoxy groups or the amino groups in the organic groups is not more than 50%.

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