A solvent-borne anti-settling high solids midcoat composition and method of making the same

Abstract

The application discloses a solvent type anti-settling high-solid mid-coat composition, which is prepared from the following raw materials in parts by weight: 10-16 parts of linear saturated polyester resin, 10-16 parts of branched saturated polyester resin, 3-10 parts of methyl etherified amino resin, 3-10 parts of mixed etherified amino resin, 1-5 parts of epoxy resin, 0.4-1.5 parts of oxidized polyethylene wax, 0.2-0.8 parts of deflocculation type dispersant, 0.2-1 part of flocculation control type dispersant, 25-45 parts of titanium white, 1-6 parts of talcum powder, 0-10 parts of barium sulfate, 0.1-0.5 parts of leveling agent, 1-5 parts of alcohol ether solvent, 5-20 parts of ester solvent and 0.01-1 part of color paste. Furthermore, the application also provides a preparation method of the mid-coat composition. By controlling the adding amount and steps of the two dispersants, the mid-coat composition has good anti-settling performance while meeting the requirements of high solid content and low VOC, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coating technology. More particularly, it relates to a solvent-based anti-settling high solid mid-coat composition and a preparation method thereof. BACKGROUND

[0002] With the development of economy, people's environmental awareness is enhanced, and the state's requirements for environmental protection are becoming more and more stringent. Solvent-based coatings are still widely used due to their excellent performance and high cost performance. At the same time, in order to meet the requirements of environmental protection, solvent-based coatings are developing towards high solid and low VOC. In order to pursue low VOC requirements, solvent-based high solid coatings will use too much and dense powder, small molecular weight resin and strong solvent, which will lead to the problem that high solid coatings are prone to settle and have poor storage stability.

[0003] Therefore, it is necessary to provide a solvent-based high solid coating with good anti-settling performance. SUMMARY

[0004] An object of the present application is to provide a solvent-based anti-settling high solid mid-coat composition with high solid, low VOC and excellent anti-settling performance.

[0005] Another object of the present application is to provide a preparation method of a solvent-based anti-settling high solid mid-coat composition.

[0006] To achieve the above-mentioned objects, the present application adopts the following technical solutions:

[0007] A solvent-based anti-settling high solid mid-coat composition, the raw materials of which include, by weight: 10-16 parts of linear saturated polyester resin, 10-16 parts of branched saturated polyester resin, 3-10 parts of methyl etherified amino resin, 3-10 parts of mixed etherified amino resin, 1-5 parts of epoxy resin, 0.4-1.5 parts of oxidized polyethylene wax, 0.2-0.8 parts of deflocculation type dispersant, 0.2-1 parts of controlled flocculation type dispersant, 25-45 parts of titanium dioxide, 1-6 parts of talc, 0-10 parts of barium sulfate, 0.1-0.5 parts of leveling agent, 1-5 parts of alcohol ether solvent, 5-20 parts of ester solvent, and 0.01-1 parts of color paste.

[0008] The preparation method of the mid-coat composition includes a grinding process and a paint mixing process.

[0009] The deflocculation type dispersant is used in the grinding process, and the controlled flocculation type dispersant is used in both the grinding process and the paint mixing process.

[0010] Preferably, the weight ratio of the deflocculation type dispersant to the controlled flocculation type dispersant is 1: (1.1-2).

[0011] Preferably, the deflocculating dispersant is an unsaturated polycarboxylic acid polymer and a polysiloxane copolymer.

[0012] Preferably, the deflocculating dispersant is DISPER BYK 110 produced by BYK Chemical or / and LADIS 131 produced by Kao.

[0013] Preferably, the main component of the controlled flocculation dispersant is an unsaturated polyamine amide and an acidic polyester salt.

[0014] Preferably, the controlled flocculation dispersant is BYK-ATU (BYK) produced by BYK Chemical or / and kilobond KB-203 produced by Qianju Fine Chemicals.

[0015] Preferably, the oxidized polyethylene wax is DeuRheo 202P produced by Hymenst.

[0016] Preferably, the alcohol ether solvent is dipropylene glycol dimethyl ether or / and propylene glycol methyl ether.

[0017] Preferably, the ester solvent is selected from one or more of butyl acetate, dimethyl carbonate, propylene glycol methyl ether acetate, and 3-hexyloxypropyl acetate.

[0018] Preferably, the linear saturated polyester resin is selected from VIALKYD® AN950 / 70X produced by Zhanxin Resin or / and AK3023 produced by Tongde Chemical.

[0019] Preferably, the branched saturated polyester resin is selected from NL301H or / and NL387 produced by Kangming Chemical.

[0020] A method for preparing a solvent-based anti-settling high solid content mid-coat composition as described above, comprising the following steps:

[0021] S1. Grinding process: according to the raw material ratio, under the condition of stirring at a speed of 500-800 r / min, 2 / 3 of the linear saturated polyester resin, 2 / 3 of the branched and polyester resin, the alcohol ether solvent, 1 / 2 of the ester solvent, the deflocculating dispersant, part of the controlled flocculation dispersant, the oxidized polyethylene wax, titanium dioxide, talc, and barium sulfate are sequentially added to the reaction kettle, stirring for 15-20 minutes, using a sand mill to grind to a fineness of ≤15 μm, and preparing a grinding slurry;

[0022] S2. Paint adjusting process: under the condition of stirring at a speed of 400-500 r / min, the remaining 1 / 3 of the linear saturated polyester resin, 1 / 3 of the branched and polyester resin, the methyl etherified amino resin, the mixed etherified amino resin, the epoxy resin, the remaining part of the controlled flocculation dispersant, 1 / 2 of the ester solvent, and the leveling agent are sequentially added to the grinding slurry, and the color is adjusted to the appropriate color using a color paste, and the process is completed.

[0023] Preferably, the weight fraction of the part of the flocculation control dispersant added in S1 is equal to the weight fraction of the deflocculation type dispersant.

[0024] The beneficial effects of the present application are as follows:

[0025] The present application provides a solvent-based high solid mid-coat composition, in which two types of polyester resins improve the flexibility of the paint film, two types of amino resins also improve the yellowing resistance, hardness and weather resistance of the paint film, two types of dispersants improve the dispersibility of the powder in the paint and also improve the anti-settling effect, the dispersant and the oxidized polyethylene wax are used together to further enhance the anti-settling effect. In the preparation process of the mid-coat composition, the flocculation control dispersant is added separately in the grinding process (S1 step) and the paint adjusting process (S2 step), and the deflocculation type dispersant is only added in the grinding process (S1 step), which further improves the anti-settling effect of the mid-coat composition. Therefore, the solvent-based high solid mid-coat composition of the present application not only meets the requirements of high solid content and low VOC, but also has good anti-settling performance, and has good application prospect. DETAILED DESCRIPTION

[0026] In order to more clearly illustrate the present application, the present application will be further described below in conjunction with preferred embodiments. Those skilled in the art should understand that the specific description below is illustrative and not limiting, and should not limit the scope of protection of the present application.

[0027] In order to improve the solid content and reduce VOC, the solvent-based high solid mid-coat composition in the prior art uses a large amount of powder with high density, resin with small molecular weight and solvent with strong solubility, which can cause the solid content in the paint to settle easily and the storage stability of the paint to be poor. The present application optimizes the types, proportions and preparation methods of the raw materials of the mid-coat composition to obtain a solvent-based high solid mid-coat composition with excellent anti-settling performance. The specific technical solution is as follows.

[0028] A solvent-based anti-settling high solid mid-coat composition, the raw materials of which include, by weight fraction: 10-16 parts of linear saturated polyester resin, 10-16 parts of branched saturated polyester resin, 3-10 parts of methyl etherified amino resin, 3-10 parts of mixed etherified amino resin, 1-5 parts of epoxy resin, 0.4-1.5 parts of oxidized polyethylene wax, 0.2-0.8 parts of deflocculation type dispersant, 0.2-1 parts of flocculation control dispersant, 25-45 parts of titanium dioxide, 1-6 parts of talc, 0-10 parts of barium sulfate, 0.1-0.5 parts of leveling agent, 1-5 parts of alcohol ether solvent, 5-20 parts of ester solvent, and 0.01-1 parts of color paste.

[0029] The preparation method of the intermediate coating composition comprises a grinding process and a paint mixing process.

[0030] The deflocculation type dispersant is used in the grinding process, and the controlled flocculation type dispersant is used in both the grinding process and the paint mixing process.

[0031] The raw materials of the intermediate coating composition in the present application include two types of polyester resins, two types of dispersants, and two types of amino resins, which are matched with oxidized polyethylene wax, epoxy resin, pigment, solvent, color paste, and leveling agent. The optimized types and weight portions of the raw materials make the intermediate coating composition have high solid content, low VOC, and good anti-settling performance.

[0032] Specifically, the two types of polyester resins can improve the flexibility of the paint film, and the two types of amino resins can improve the yellowing resistance, hardness, and weather resistance of the paint film. The two types of dispersants can improve the dispersion of the powder in the paint and the anti-settling effect. The dispersant and the oxidized polyethylene wax are matched to further enhance the anti-settling effect.

[0033] In addition, the addition of the deflocculation type dispersant and the controlled flocculation type dispersant in the grinding process of the intermediate coating composition can disperse and stabilize the grinding slurry. The addition of the controlled flocculation type dispersant in the paint mixing process can not only make up for the loss of the dispersant from the surface of the powder, but also form hydrogen bonds in the system to improve the anti-settling effect of the system. However, the deflocculation type dispersant cannot be added in the paint mixing process because it can cause the powder to settle. Therefore, the matching of the dispersants is also crucial for obtaining the intermediate coating composition with good stability, high solid content, low VOC, and good anti-settling performance.

[0034] The intermediate coating composition in the present application includes two types of dispersants. The deflocculation type dispersant can better disperse the powder and has good pick-up effect, but the powder is easy to settle if it is used alone. The controlled flocculation type dispersant has good anti-settling effect, but it can cause poor dispersion of the powder and easy settlement if it is used alone or in excess. In some preferred examples, the weight ratio of the deflocculation type dispersant to the controlled flocculation type dispersant is 1: (1.1-2). By controlling the usage ratio, the dispersion of the powder in the paint can be improved, and the anti-settling effect can also be improved.

[0035] In the specific implementation process, the deflocculation type dispersant is an unsaturated polycarboxylic acid polymer and a polysiloxane copolymer. The unsaturated polycarboxylic acid polymer has a low molecular weight. The deflocculation type dispersant can be obtained by commercial purchase, including but not limited to DISPER BYK110 produced by Bichemical and LADIS131 produced by Kao.

[0036] The main component of the control flocculation type dispersant is unsaturated polyamine amide and acid polyester salt; wherein, the acid polyester salt is low molecular weight. The control flocculation type dispersant can be obtained by commercial purchase, including but not limited to BYK-ATU (BYK) produced by BYK Chemical or / and kilobond KB-203 produced by Qianju Fine Chemicals, etc. The control flocculation type dispersant is used in solvent type system, which can prevent the settlement of fillers and inorganic pigments in medium polarity to low polarity thick coating system and primer, and has good stability and anti-settling effect.

[0037] The processing dispersant of the present application is used in combination with oxidized polyethylene wax, which can have good anti-settling effect. The wax alone can prevent hard precipitation, but cannot slow down the settlement of powder, and excessive use will cause poor adhesion and large VOC; while the dispersant can disperse the powder well, but the powder is prone to settlement due to its large density, and the combination can achieve better anti-settling effect and meet the VOC requirements. In some preferred examples, the oxidized polyethylene wax is DeuRheo 202P produced by Hymenster, which can prevent pigment settlement and avoid hard deposition of powder at the bottom of the storage.

[0038] The present application adjusts the type and weight of the solvent, which plays the role of diluent, moisturizes the color paste, reduces caking, and adjusts the volatilization gradient of the solvent to obtain good paint film appearance. In some preferred examples, the alcohol ether solvent is dipropylene glycol dimethyl ether or / and propylene glycol methyl ether; the ester solvent includes but is not limited to butyl acetate, dimethyl carbonate, propylene glycol methyl ether acetate, 3-hexyloxypropyl acetate, etc.

[0039] The linear saturated polyester resin has good yellowing resistance and flexibility, and the branched saturated polyester resin has good aging resistance, color retention, hardness and overbaking resistance. In some preferred examples, the linear saturated polyester resin is selected from alcohol resin VIALKYD® AN 950 / 70X produced by Zhanxin Resin or / and AK3023 produced by Tongde Chemical. The branched saturated polyester resin is selected from NL301H or / and NL387 produced by Kangming Chemical, which has outstanding aging resistance, excellent flowability and good pigment wetting, and is mainly applied in coil coating and automotive coating fields.

[0040] Methyl etherified amino resin has high reactivity and high self-condensation tendency, and the formed paint film has very good hardness, gloss, chemical resistance and outdoor durability, and has the advantages of fast drying in low temperature environment, and can balance the hardness and flexibility of the paint film. In some preferred examples, the methyl etherified amino resin is selected from commercially available products, including but not limited to CYMEL325 or / and CYMEL327 produced by Zhanxin Amino Resin.

[0041] In some preferred examples, the mixed etherified amino resin is selected from one or more of CYMEL 1130, CYMEL 202, CYMEL 203. The mixed etherified amino resin has good storage stability and wide compatibility.

[0042] In some preferred examples, the epoxy resin is E-44 epoxy resin, such as the E-44 from Baling Petrochemical which can provide good adhesion.

[0043] The coating composition in the present application includes titanium dioxide, talc and barium sulfate, all of which can be obtained by commercial purchase. For example, R-706 from DuPont and R-996 from Longam have good dispersibility and whiteness. JLH-60 talc from Jinhuo Hui has good fineness (≤5 μm), is easy to disperse, has good anti-settling stability, and can improve the anti-settling effect of the system. In addition, JLH-B7 and JLH-BF3 barium sulfate from Jinhuo Hui are used as fillers, have good fineness (≤5 μm), are easy to disperse, have good anti-settling stability, and are not easy to harden.

[0044] The leveling agent has anti-cratering performance and leveling performance, can improve the gloss of the coating and improve the long-wave leveling effect, slightly reduces the surface tension, but does not affect the recoatability and interlayer adhesion. BYK-352 leveling agent from BYK-Chemie also has defoaming function and good thermal stability.

[0045] A small amount of color paste is also included in the coating composition in the present application, which mainly plays a color adjusting role. The color paste used is self-made or commercially available color paste, which is red paste, black paste and yellow paste for color adjustment.

[0046] The second aspect of the present application provides a preparation method of the above-mentioned solvent-based anti-settling high solid content coating composition, which comprises the following steps:

[0047] S1. Grinding process: according to the raw material ratio, 2 / 3 of the linear saturated polyester resin, 2 / 3 of the branched polyester resin, alcohol ether solvent, 1 / 2 of the ester solvent, deflocculation type dispersant, part of the flocculation control dispersant, oxidized polyethylene wax, titanium dioxide, talc, barium sulfate are sequentially added into the reaction kettle under the condition of stirring at a speed of 500-800 r / min, and stirred for 15-20 minutes. A sand mill is used to grind the fineness to ≤15 μm to prepare a grinding paste;

[0048] S2. Paint adjusting process: under the condition of stirring at a speed of 400-500 r / min, the remaining 1 / 3 of the linear saturated polyester resin, 1 / 3 of the branched polyester resin, methyl etherified amino resin, mixed etherified amino resin, epoxy resin, the remaining part of the flocculation control dispersant, 1 / 2 of the ester solvent, leveling agent are sequentially added into the grinding paste, and the color is adjusted to the appropriate color using color paste.

[0049] In the preparation of the coating composition in the present application, the controlled flocculation type dispersant is added separately in the grinding process (step S1) and the paint adjusting process (step S2). In some preferred examples, the weight fraction of the controlled flocculation type dispersant added in S1 is equal to the weight fraction of the deflocculation type dispersant. The addition of equal amounts of controlled flocculation type dispersant and deflocculation type dispersant in the grinding process can play a role in dispersing and stabilizing the grinding slurry, and the addition of controlled flocculation type dispersant in the paint adjusting process can not only make up for the dispersant that falls off the surface of the powder during the paint adjusting process, but also form hydrogen bonds in the system, thereby improving the anti-settling effect of the system. Deflocculation type dispersants cannot be added in the paint adjusting process as they can cause the powder to precipitate.

[0050] The technical solutions of the present application will be described below in conjunction with specific examples

[0051] Examples

[0052] The information of the raw materials used in the following examples is as follows:

[0053] Linear saturated polyester resin: alkyd resin VIALKYD® AN 950 / 70X produced by Zhanxin Resin or AK3023 produced by Tongde Chemical.

[0054] Branched saturated polyester resin: NL301H or / and NL387 produced by Kangming Chemical.

[0055] Methyl etherified amino resin: CYMEL325 or / and CYMEL327 produced by Zhanxin Amino Resin.

[0056] Mixed etherified amino resin: CYMEL1130, CYMEL 202, CYMEL203 produced by Zhanxin Amino Resin.

[0057] Epoxy resin: E-44 produced by Balin Petrochemical.

[0058] Oxidized polyethylene wax: DeuRheo 202P produced by Haimingsideqian.

[0059] Deflocculation type dispersant: DISPER BYK110 produced by Bicheng Chemical or LADIS131 produced by Kaishida.

[0060] Controlled flocculation type dispersant: BYK-ATU (BYK) produced by Bicheng Chemical or kilobond KB-203 produced by Qianjuzhunshichong.

[0061] Titanium dioxide: R-706 produced by DuPont or R-996 produced by Longpang.

[0062] Talc: JLH-60 produced by Jinhuo Hui Company.

[0063] Barium sulfate: JLH-B7 and JLH-BF3 of Jinhuai Company.

[0064] Leveling agent: BYK-352 of BYK-Chemical.

[0065] Alcohol ether solvent: dipropylene glycol dimethyl ether or / and propylene glycol methyl ether

[0066] Ester solvent: butyl acetate, dimethyl carbonate, propylene glycol methyl ether acetate, 3-hexyloxypropyl acetate.

[0067] The preparation process of the intermediate coating composition in the examples and comparative examples is as follows:

[0068] S1. Grinding process: according to the proportion of the raw materials, 2 / 3 of the linear saturated polyester resin, 2 / 3 of the branched polyester resin, alcohol ether solvent, 1 / 2 of the ester solvent, deflocculation type dispersant, part of the flocculation control dispersant, oxidized polyethylene wax, titanium dioxide, talc, and barium sulfate are sequentially added to the reaction kettle under the condition of stirring at a speed of 500-800 r / min, and stirred for 15-20 minutes. The sand mill is used to grind the fineness to ≤15 μm, and the grinding slurry is prepared;

[0069] S2. Paint adjusting process: under the condition of stirring at a speed of 400-500 r / min, the remaining 1 / 3 of the linear saturated polyester resin, 1 / 3 of the branched polyester resin, methyl etherified amino resin, mixed etherified amino resin, epoxy resin, the remaining part of the flocculation control dispersant, 1 / 2 of the ester solvent, and leveling agent are sequentially added to the grinding slurry, and the color paste is adjusted to the appropriate color.

[0070] The specific types and weight parts of the raw materials of the intermediate coating composition in the examples and comparative examples are shown in Table 1:

[0071] Table 1 Raw material formula of the intermediate coating composition in the examples and comparative examples

[0072]

[0073] The performance test of the coating in the examples and comparative examples is carried out, and the results are shown in Table 2:

[0074] Table 2 Performance of the coating in the examples and comparative examples

[0075]

[0076] Note: The heat storage and precipitation description (from good to bad) in Table 2 is as follows: no precipitation > light soft precipitation > soft precipitation > serious soft precipitation > hard precipitation > hardening

[0077] The coating performance in Table 2 shows that the coating composition in the present application has excellent anti-settling performance, excellent storage stability, and as the amount of oxidized polyethylene wax increases, the stability also increases, the dispersant can also reduce the amount, but the VOC value will also increase, the impact, cupping and other appearance and physical properties will also be poor, therefore, within the scope defined in the present application, the stability, VOC value and impact, cupping and other physical properties can be balanced. Comparative Examples 1-3 show that if only a controlled flocculation type dispersant is used in the grinding process or a deflocculation type dispersant is used in the paint mixing process, the anti-settling performance of the paint film will be poor, and the gloss will also be reduced.

[0078] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not a limitation on the embodiments of the present application. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description, and it is impossible to enumerate all the embodiments here. Any obvious changes or variations derived from the technical solutions of the present application are still within the protection scope of the present application.

Claims

1. A solvent-borne, anti-settling, high-solids midcoat composition characterized in that, The raw materials include, by weight parts, 10-16 parts of linear saturated polyester resin, 10-16 parts of branched saturated polyester resin, 3-10 parts of methyl etherified amino resin, 3-10 parts of mixed etherified amino resin, 1-5 parts of epoxy resin, 0.4-1.5 parts of oxidized polyethylene wax, 0.2-0.8 parts of deflocculation type dispersant, 0.2-1 part of controlled flocculation type dispersant, 25-45 parts of titanium white, 1-6 parts of talc, 0-10 parts of barium sulfate, 0.1-0.5 parts of leveling agent, 1-5 parts of alcohol ether solvent, 5-20 parts of ester solvent, and 0.01-1 part of color paste; The preparation method of the intermediate coating composition comprises a grinding process and a paint adjusting process; The deflocculation type dispersant is used in the grinding process, and the controlled flocculation type dispersant is used in both the grinding process and the paint adjusting process.

2. The intermediate coating composition according to claim 1, characterized in that The weight ratio of the deflocculation type dispersant to the controlled flocculation type dispersant is 1: (1.1-2).

3. The intermediate coating composition according to claim 1, characterized in that The deflocculation type dispersant is an unsaturated polycarboxylic acid polymer and a polysiloxane copolymer.

4. The intermediate coating composition according to claim 1, characterized in that The controlled flocculation type dispersant mainly comprises an unsaturated polyamine amide and an acidic polyester salt.

5. The intermediate coating composition according to claim 4, characterized in that The controlled flocculation type dispersant is BYK-ATU (BYK) produced by BYK Chemical or / and kilobond KB-203 produced by Qianjuxing Fine Chemicals.

6. The intermediate coating composition according to claim 1, characterized in that The oxidized polyethylene wax is DeuRheo 202P produced by Hymenster.

7. The intermediate coating composition according to claim 1, characterized in that The alcohol ether solvent is dipropylene glycol dimethyl ether or / and propylene glycol methyl ether.

8. The intermediate coating composition according to claim 1, characterized in that The ester solvent is selected from one or more of butyl acetate, dimethyl carbonate, propylene glycol methyl ether acetate, and 3-hexyloxypropyl acetate.

9. The intermediate coating composition according to claim 1, characterized in that The linear saturated polyester resin is selected from alcohol resin VIALKYD® AN 950 / 70X produced by Zhanxin Resin or / and AK3023 produced by Tongde Chemical.

10. A process for the preparation of a solvent borne, anti-settling, high solids mid-coat composition as claimed in any one of claims 1 to 9, characterised in that, The method comprises the following steps: S1. Grinding process: according to the raw material ratio, 2 / 3 of the linear saturated polyester resin, 2 / 3 of the branched saturated polyester resin, the alcohol ether solvent, 1 / 2 of the ester solvent, the deflocculation type dispersant, part of the controlled flocculation type dispersant, the oxidized polyethylene wax, the titanium white, the talc, and the barium sulfate are sequentially added into a reaction kettle under the condition of stirring at a speed of 500-800 r / min, and stirring is performed for 15-20 minutes, and a grinding slurry with a fineness of ≤15 μm is prepared by using a sand mill; S2. Paint adjusting process: the remaining 1 / 3 of the linear saturated polyester resin, 1 / 3 of the branched saturated polyester resin, the methyl etherified amino resin, the mixed etherified amino resin, the epoxy resin, the remaining controlled flocculation type dispersant, 1 / 2 of the ester solvent, and the leveling agent are sequentially added into the grinding slurry under the condition of stirring at a speed of 400-500 r / min, and a color paste is used to adjust the color to a proper color.

11. The method of claim 10, wherein, The weight parts of the part of the controlled flocculation type dispersant added in S1 are equal to the weight parts of the deflocculation type dispersant.

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