阅读说明：本技术 一种抗石击溶剂型汽车中涂漆 (Stone-attack-resistant solvent-type automobile intermediate coating ) 是由 岑栋杰 于 2021-05-19 设计创作，主要内容包括：本发明公开了一种抗石击溶剂型汽车中涂漆,所述溶剂型汽车中涂漆包含以下重量份的组分：聚酯树脂15-25份、豆油酸改性醇酸树脂10-15份、氨基树脂10-15份、环氧树脂2-4份、填料40-50份、分散剂1-2份、消泡剂0.5-1份、电阻调节剂1-3份、流平剂1-2份和稀释剂40-50份。所述汽车中涂漆含有的聚酯树脂结构中含有大量的五元环或六元环,五元环或六元环存在不同的稳定构象,如六元环具有船式构象和椅式构象,五元环具有信封式构象和半椅式构象,两种构象都可以相互转变,当涂层材料受到冲击时,环的构象翻转调整,从而缓冲吸收冲击的能量,避免涂层受到严重的损害。(The invention discloses a stone-impact-resistant solvent-based automobile primer surfacer which comprises the following components in parts by weight: 15-25 parts of polyester resin, 10-15 parts of soya-bean oil acid modified alkyd resin, 10-15 parts of amino resin, 2-4 parts of epoxy resin, 40-50 parts of filler, 1-2 parts of dispersing agent, 0.5-1 part of defoaming agent, 1-3 parts of resistance regulator, 1-2 parts of flatting agent and 40-50 parts of diluent. The polyester resin structure of the automobile intermediate coat contains a large number of five-membered rings or six-membered rings, the five-membered rings or the six-membered rings have different stable conformations, for example, the six-membered rings have ship conformations and chair conformations, the five-membered rings have envelope conformations and half chair conformations, the two conformations can be mutually converted, and when the coating material is impacted, the conformations of the rings are overturned and adjusted, so that the impact energy is buffered and absorbed, and the coating is prevented from being seriously damaged.)

1. The stone-impact-resistant solvent-based automobile middle coating is characterized by comprising the following components in parts by weight:

15-25 parts of polyester resin, 10-15 parts of soya-bean oil acid modified alkyd resin, 10-15 parts of amino resin, 2-4 parts of epoxy resin, 40-50 parts of filler, 1-2 parts of dispersing agent, 0.5-1 part of defoaming agent, 1-3 parts of resistance regulator, 1-2 parts of flatting agent and 40-50 parts of diluent;

the structural formula of the polyester resin is shown as the formula (I):

（I）

wherein R is₁And R₂Any one or more of the following components in percentage by weight:

、、、and；

R₃is one or more of 1,2, 3-benzene tricarboxylic acid, 1,2, 4-benzene tricarboxylic acid, 1,3, 5-benzene tricarboxylic acid, 1,2, 3-propane tricarboxylic acid and cis-aconitic acid; n is an integer of 15 to 50.

2. The paint as claimed in claim 1, wherein the weight average molecular weight of the soya oil acid modified alkyd resin is 10000-20000, and the hydroxyl value is 80-100.

3. The stone-chip solvent resistant automotive basecoat of claim 1 wherein said polyester resin has a weight average molecular weight of 10000-30000 and a hydroxyl number of 80-100.

4. The stone-chip solvent resistant automotive basecoat of claim 1 wherein said amino resin has a weight average molecular weight of 3000-4000.

5. The stone-chip solvent resistant automotive basecoat of claim 1 wherein said epoxy resin has an epoxy equivalent weight of 150-200.

6. The stone-impact resistant solvent-borne automotive basecoat material of claim 1 wherein said dispersant is at least one of a polyamide compound and a hyperbranched polymer.

7. The stone-chip solvent resistant automotive basecoat of claim 1 wherein said electrical resistance modifier is at least one of methanol, diacetone alcohol and ethylene glycol ethyl ether; the diluent is at least one of toluene, xylene, isobutanol, n-butanol, ethylene glycol butyl ether, propylene glycol butyl ether and ethyl acetate.

8. The stone-chip solvent resistant automotive basecoat of claim 1 wherein said leveling agent is at least one of a silicone modified acrylic and an organofluorine modified acrylic.

9. The stone-chip solvent resistant automotive basecoat material of claim 1 wherein said polyester resin is prepared by a process comprising the steps of:

s1, heating and reacting the dihydric alcohol and the dibasic acid under the action of a catalyst, purging with nitrogen in the reaction process, and separating the generated water by using a water separator to obtain a hydroxyl-terminated polyester resin prepolymer;

s2, adding a tribasic acid into the hydroxyl-terminated polyester resin prepolymer obtained in the step S1, heating and reacting under the action of a catalyst, purging with nitrogen in the reaction process, and separating generated water by using a water separator to obtain polyester resin with a cross-linked structure;

s3 adding xylene as a reflux solvent into the polyester resin with the crosslinking structure obtained in the S2, and refluxing to obtain the polyester resin.

10. The stone-chip solvent resistant automotive basecoat of claim 9 wherein said catalyst is a tin-based catalyst; in S1 and S2, the temperature of the heating reaction is 190-210 ℃, and the time is 2-4 h.

Technical Field

The invention relates to a coating, and in particular relates to a stone-impact-resistant solvent-based automobile primer surfacer.

Background

The holding capacity of the passenger cars in China is continuously increased, cars are used as important daily tools for people when going out, the cars are easily impacted by hard objects such as stones during the running process, and the damage of the impact on the car surface coating is larger when the running speed of the cars is higher. Once the automotive coating is knocked off, the automotive steel plate is exposed to corrosion. Therefore, the chip resistance of automotive coatings is considered to be one of the important characteristics during their use. The automobile coating is a composite coating, and is composed of an electrophoretic primer, a middle coating, a colored paint and a varnish on the uppermost layer from bottom to top. According to the functional design of each layer of the automobile coating, the middle coating layer mainly plays a role in resisting stone impact. The polyester resin is the main component of the middle coating, and the improvement of the shock resistance of the polyester resin is most effective to the stone impact resistance of the coating.

In the disclosed technology, the stone-impact resistance of polyester is generally improved by a modification method. The polyester is prepared by reacting a polyol with a polybasic acid, and the common polyols include neopentyl glycol, 2-methyl-1, 3-propanediol, and trimethylolpropane. Common polybasic acids are adipic acid, succinic acid, terephthalic acid, isophthalic acid, and the like. The prepared polyester resin has poor flexibility and cannot well meet the application requirement of the automobile coating. In order to improve the impact resistance of polyester, application number CN 201110025407.6 (a polyester resin and a preparation method thereof and an automobile middle coating) discloses a modified polyester resin with inorganic nano-material polyhedral oligomeric silsesquioxane (POSS), cn201110194684 x (a polyamide modified polyester resin and a preparation method thereof and an automobile middle coating containing the polyester resin) discloses a method for modifying polyester with polyamide. Whether the polyester is modified by inorganic filler or organic polymer, the stone-impact resistance is improved by adding modifying substances, the filler with a pore structure, such as POSS, is added, if the filler is not uniformly dispersed, the appearance of a coating is affected, and the mechanical properties, such as corrosion resistance, are affected by the cavities and the nonuniform structure, and moisture is easy to penetrate deeply and stays in the polyester resin containing the POSS. If the compatibility between the organic polymer polyamide and the modified polyester is poor, phase separation is easy to occur. Therefore, the best scheme for improving the stone-impact resistance of the polyester material is to improve the impact resistance and flexibility of the polyester intrinsic material.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a solvent-based intermediate coating containing cycloaliphatic polyester, wherein the intermediate coating has better stone-impact resistance than the prior art.

In order to achieve the purpose, the invention adopts the technical scheme that: the stone-impact-resistant solvent-based automobile primer surfacer comprises the following components in parts by weight:

15-25 parts of polyester resin, 10-15 parts of soya-bean oil acid modified alkyd resin, 10-15 parts of amino resin, 2-4 parts of epoxy resin, 40-50 parts of filler, 1-2 parts of dispersing agent, 0.5-1 part of defoaming agent, 1-3 parts of resistance regulator, 1-2 parts of flatting agent and 40-50 parts of diluent;

the structural formula of the polyester resin is shown as the formula (I):

（I）

wherein R is₁And R₂Any one or more of the following components in percentage by weight:

、、、and；

R₃is one or more of 1,2, 3-benzene tricarboxylic acid, 1,2, 4-benzene tricarboxylic acid, 1,3, 5-benzene tricarboxylic acid, 1,2, 3-propane tricarboxylic acid and cis-aconitic acid; n is an integer of 15 to 50.

The addition of polyester resins to the basecoat serves to adjust the flexibility of the basecoat in the vehicle and, thus, the chip resistance of the resulting coating after curing. The soya-bean oil acid modified alkyd resin is added to mainly improve the anti-sagging and anti-settling properties of the coating. The amino resin is added mainly to promote curing of the coating film and to increase hardness. The epoxy resin is added mainly to improve the adhesion of the intercoat to the substrate.

The preparation method of the automobile primer surfacer comprises the steps of mixing the components, uniformly stirring, and then grinding to obtain the primer surfacer with the solid content of 60 +/-5%.

The application of the intermediate coating can be that the intermediate coating is diluted to 22 +/-1 seconds of construction viscosity (Ford 4# cup) by a solvent, the coating is sprayed on the electrophoretic coating, the construction film thickness is 30-40 microns, and the intermediate coating is baked for 10-30 minutes at the temperature of 140-. Obtaining the automobile middle coating. Preferably, the weight-average molecular weight of the soyaoleic acid modified alkyd resin is 10000-20000, and the hydroxyl value is 80-100.

Preferably, the polyester resin has a weight average molecular weight of 10000-30000 and a hydroxyl value of 80-100.

Preferably, the amino resin has a weight average molecular weight of 3000-4000.

Preferably, the epoxy resin has an epoxy equivalent weight of 150-200.

Preferably, the dispersant is at least one of a polyamide compound, a hyperbranched high polymer acetylenic diol wetting agent, and an alcohol ammonium salt.

Preferably, the resistance regulator is at least one of methanol, diacetone alcohol and ethylene glycol ethyl ether; the diluent is at least one of toluene, xylene and isobutanol, and is selected from n-butyl alcohol, ethylene glycol butyl ether, propylene glycol butyl ether and ethyl acetate; the defoaming agent is preferably a foam breaking polysiloxane compound of Germany BYK company, and the filler is at least one of titanium dioxide, barium sulfate, kaolin and carbon black.

Preferably, the preparation method of the polyester resin comprises the following steps:

s1, heating and reacting the dihydric alcohol and the dibasic acid under the action of a catalyst, purging with nitrogen in the reaction process, and separating the generated water by using a water separator to obtain a hydroxyl-terminated polyester resin prepolymer;

s2, adding a tribasic acid into the hydroxyl-terminated polyester resin prepolymer obtained in the step S1, heating and reacting under the action of a catalyst, purging with nitrogen in the reaction process, and separating generated water by using a water separator to obtain polyester resin with a cross-linked structure;

s3 adding xylene as a reflux solvent into the polyester resin with the crosslinking structure obtained in the S2, and refluxing to obtain the polyester resin.

Preferably, the catalyst is a tin-based catalyst; more preferably, the tin catalyst can be at least one of dibutyltin dilaurate, dibutyltin oxide and stannous octoate, and the feeding amount is 0.05-0.2%. In S1 and S2, the temperature of the heating reaction is 190-210 ℃, and the time is 2-4 h.

The invention has the beneficial effects that: the invention provides a stone-impact-resistant solvent-based automobile primer, which contains a polyester resin structure containing a large number of five-membered rings or six-membered rings, wherein the five-membered rings or the six-membered rings have different stable conformations, for example, the six-membered rings have a boat conformation and a chair conformation, the five-membered rings have an envelope conformation and a half-chair conformation, the two conformations can be mutually converted, and when a coating material is impacted, the conformations of the rings are overturned and adjusted, so that the impact energy is buffered and absorbed, and the coating is prevented from being seriously damaged.

Drawings

FIG. 1 is the stone chip resistance of example 1;

FIG. 2 is the stone chip resistance of example 2;

FIG. 3 is the stone chip resistance of example 3;

FIG. 4 shows the stone chip resistance of comparative example 1.

Detailed Description

To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples.

The source of each raw material component in the examples and comparative examples is as follows:

soya-bean-oil-acid-modified alkyd resin: SY9701

Amino resin: FB717

Epoxy resin: EP-430

Filling: titanium dioxide;

dispersing agent: BYK-180 dispersant;

defoaming agent: DM-F45PS

Resistance adjuster: methanol;

leveling agent: BYK-381;

diluent agent: isobutanol.

Example 1

The automobile primer surfacer comprises the following components in parts by weight:

25 parts of polyester resin, 12 parts of soya-bean oil acid modified alkyd resin, 12 parts of amino resin, 3 parts of epoxy resin, 45 parts of filler, 1 part of dispersing agent, 0.5 part of defoaming agent, 2 parts of resistance regulator, 2 parts of flatting agent and 45 parts of diluent.

The structure of the polyester resin described in this example is shown in formula (II):

（II）

wherein R is₁And R₂Is composed of；

The preparation method of the water-based polyester dispersion liquid comprises the following steps:

s1, adding 42 parts of 1, 4-cyclohexanediol, 57.5 parts of 1, 4-cyclohexanedicarboxylic acid and 0.5 part of dibutyltin dilaurate into a reaction kettle provided with a water separator, a reflux condenser, a stirrer, a thermometer and protective gas, slowly heating to 200 ℃, purging with nitrogen in the reaction process, and reacting for 3 hours to obtain the hydroxyl-terminated polyester resin prepolymer:

；

R₁and R₂Is composed of；

S2, continuously cooling to 150 ℃ under the protection of nitrogen, then adding 1,3, 5-benzenetricarboxylic acid accounting for 5 percent of the mass of the prepolymer, heating to 210 ℃, purging with nitrogen in the reaction process, and reacting for 3 hours;

s3, adding dimethylbenzene accounting for 10% of the mass of the prepolymer for refluxing for 1h, then vacuumizing and preserving heat for 30min, and taking out residual water in the system by using the dimethylbenzene; reducing the temperature to 120 ℃, adding xylene and propylene glycol monomethyl ether to a reaction mixture of 1: 2 to obtain the polyester resin with the solid mass fraction of about 60 percent.

Example 2

The automobile primer surfacer comprises the following components in parts by weight:

15 parts of polyester resin, 10 parts of soya-bean oil acid modified alkyd resin, 15 parts of amino resin, 2 parts of epoxy resin, 45 parts of filler, 1 part of dispersing agent, 0.5 part of defoaming agent, 2 parts of resistance regulator, 2 parts of flatting agent and 45 parts of diluent.

The structure of the polyester resin described in this example was the same as that of example 1.

Example 3

The automobile primer surfacer comprises the following components in parts by weight:

25 parts of polyester resin, 15 parts of soya-bean oil acid modified alkyd resin, 10 parts of amino resin, 4 parts of epoxy resin, 45 parts of filler, 1 part of dispersing agent, 0.5 part of defoaming agent, 2 parts of resistance regulator, 2 parts of flatting agent and 45 parts of diluent.

The structure of the polyester resin described in this example was the same as that of example 1.

Comparative example 1

Comparative example 1 differs from example 1 in that the equivalent amounts of solvents xylene and propylene glycol monomethyl ether used are 1: 2 instead of the polyester resin.

The middle coats of examples 1 to 3 and comparative example 1 were sprayed on an electrophoresis plate, the thickness of the sprayed dry film was 25 μm, and the plate was baked at 150 ℃ for 20min, and then a plain white paint and a clear varnish were sprayed and baked at 150 ℃ for 20 min.

Performance testing

The thickness test of the coating film is detected according to the standard of GB/T13452.2-2008;

the adhesion test of the coating film is detected according to the standard of GB/T9286-1998;

the stone chip resistance test of the coating film was carried out according to the FLTM BI 157-06 standard.

The results are shown in Table 1.

TABLE 1

	Thickness of middle coating film/micron	Composite coating film thickness/micron	Adhesion (lattice drawing method)
				Example 1	35±2	90±2	Level 0
Example 2	35±2	90±2	Level 0
				Example 3	35±2	90±2	Level 0
Comparative example 1	35±2	90±2	Level 0

The stone-impact resistance is detected according to the standard of FLTM BI 157-06, and specifically comprises the following steps: (1) 2kg of iron sand, and striking the steel plate sprayed with the composite coating at an angle of 45 degrees by using the air pressure of 2 bar; (2) soaking in water for 72h after striking once, at 32 ℃; (3) drying the soaked materials for 1h, and repeating the step 1 once; (4) loose paint residue was removed by taping and then evaluated. The results are shown in FIGS. 1 to 4.

It can be seen from the figure that the stone chip resistance of examples 1-3 is significantly better than that of comparative example 1.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.