CN102391743B - Aqueous primer used for bicycles - Google Patents

Abstract

The invention relates to a water-based primer for bicycles, which is composed of 25-45 water-based epoxy acrylic resins, 2-10 curing agent resins, 1-3 neutralizing agents dimethyl ethanolamine, 2-10 composite antirust pigments, and colored Pigment and filler 5-20, defoamer 0.1-0.5, leveling agent 0.1-0.5, deionized water 20-40, the sum of the contents of each component is 100, and the above are percentages by weight; its water-based epoxy acrylic resin The epoxy resin accounts for 10-40% of the total weight of the resin; the curing agent resin is composed of a water-based closed polyurethane curing agent resin and an amino curing agent resin with a mass ratio of 1:5-5:1. The curing agent is unblocked and cured at 130°C. The amino curing agent resin is methanol or butanol etherified melamine formaldehyde resin; the composite antirust pigment is composed of modified zinc phosphate, zinc oxide and ion exchange antirust pigment. It is especially suitable for anti-rust and anti-corrosion of structures such as bicycles.

Description

A kind of water-based primer for bicycle

technical field

The invention relates to a water-based primer for bicycles, which is especially suitable for antirust and anticorrosion of structures such as bicycles.

Background technique

The painting of bicycles is similar to the painting of other traffic vehicles, generally using a primer, primer and topcoat system. At present, solvent-based systems are widely used in the bicycle industry in China, and a large amount of organic volatile compounds are emitted, which not only damages the environment, endangers people's health, but also wastes resources and energy. In this situation, in order to respond to the development direction of national industrial policies, bicycle manufacturers require the development of water-based paint systems for bicycles to replace solvent-based paints. However, the existing bicycle coating process is different from that of general traffic vehicles. It is required that the coating film be completely cured and dried at 135±3°C for 10 to 15 minutes, and the salt resistance and boiling water resistance of the coating film must meet the specified requirements. However, the current water-based acrylic amino system uses water-based acrylic resin as the main film-forming resin and amino resin as the curing agent resin. Since the corrosion resistance of water-based acrylic resin cannot meet the anti-corrosion requirements of bicycle coatings, although the price of amino resin is low, but After curing, the performance of the coating film is difficult to meet the anti-corrosion and anti-rust requirements. In addition, the electrophoretic system used in general traffic vehicle primers is not suitable for the process requirements of bicycle coating. Develop a kind of meeting environmental protection requirement for this reason, can satisfy the bicycle painting process requirement, have the primer of performances such as excellent anti-rust, anti-corrosion and boiling water simultaneously, seem particularly necessary to satisfy the demand that the bicycle industry develops day by day.

Contents of the invention

The purpose of the present invention is to provide a bicycle water-based primer suitable for bicycle baking conditions, with improved anti-rust, anti-corrosion and boiling water resistance and meeting environmental protection requirements.

The technical solution for realizing the object of the present invention is: a water-based primer for bicycles, characterized in that it consists of the following components, in percentages by weight, and the consumption of each component is as follows:

Water-based epoxy acrylic resin 25-45, curing agent resin 2-10, neutralizer dimethylethanolamine 1-3, composite anti-rust pigment 2-10, coloring pigment and filler 5-20, defoamer 0.1-0.5, Leveling agent 0.1-0.5, deionized water 20-40, the sum of the contents of each component is 100%;

The water-based epoxy acrylic resin is an epoxy resin modified acrylic resin, the acid value of the acrylic resin is 50-200mgKOH/g, the epoxy equivalent of the epoxy resin is 500-1500g/mol, and the epoxy resin is in the total weight of the resin 10-40% of the total;

The curing agent resin is composed of a water-based closed polyurethane curing agent resin and an amino curing agent resin with a mass ratio of 1:5 to 5:1, wherein the water-based sealing curing agent resin is unblocked and cured at 130°C, and the amino curing agent resin is cured. The agent resin is methanol etherified melamine formaldehyde resin or butanol etherified melamine formaldehyde resin;

The composite antirust pigment is composed of modified zinc phosphate, zinc oxide and ion exchange antirust pigment.

In the above-mentioned water-based primer for bicycles, the water-based epoxy acrylic resin is 500-1500 g/mol epoxy equivalent, which accounts for 10-40% of the total weight of the resin, and is heated and dissolved with a solvent and partially aminated , and then heated together with acrylic resin with an acid value of 50-200 mgKOH/g, which is formed by free-radical polymerization of acrylic acid, hydroxypropyl acrylate, butyl acrylate and styrene monomer, for catalytic esterification reaction.

In the above-mentioned water-based primer for bicycles, the water-based closed polyurethane curing agent resin in the curing agent resin is prepared by the following method: 100 parts by weight of polyisocyanate in terms of solids are added to the reaction vessel, and ≤ 25 parts by weight of auxiliary Solvent and adjust the temperature to 50°C, then add 10-30 parts by weight of blocking agent 3,5-dimethylpyrazole, keep warm for 2 hours, then raise the temperature to 60-80°C, add 2-10 parts by weight of pro- The water component is dimethylol propionic acid, heat preservation reaction for 4 hours, then cool down to 50°C, add 2 to 8 parts by weight of neutralizing agent dimethylolamine to neutralize, and then dilute with deionized water to a solid content of 40 weight %, filtered and packaged to obtain a water-based blocked polyurethane curing agent resin, wherein the polyisocyanate is 1,6-hexamethylene diisocyanate biuret or 1,6-hexamethylene diisocyanate trimer.

In the above-mentioned water-based primer for bicycles, the fillers are talcum powder and barium sulfate; the coloring pigments are carbon black and titanium dioxide; the defoamer is BYK025 from BYK, and the leveling agent is BYK331 from BYK; The conductivity of ionized water is ≤20μs/cm.

The technical effect of the present invention is: the water-based primer for bicycles of the technical solution of the present invention has the following beneficial effects: 1. the main film-former of the water-based epoxy acrylic resin as the primer improves the anti-corrosion effect. Since the water-based epoxy acrylic resin is an acrylic resin modified by an appropriate epoxy resin, the adhesion and corrosion resistance of the primer to the substrate are higher than those of the primer with water-based acrylic resin as the main film-forming substance; ②curing The agent is compounded with two curing agent resins, which improves the performance of the paint film and is suitable for the current bicycle baking process. When the primer is cured to form a film, the two compounded curing agent resins and water-based epoxy acrylic resin can obtain a paint film with a three-dimensional network structure, so that the paint film has suitable strength and toughness, especially when compounded with an appropriate amount The water-based closed polyurethane curing agent resin significantly improves the boiling water cooking resistance of the primer paint film. At the same time, the water-based closed polyurethane curing agent resin is deblocked and cured at 130°C, making the primer suitable for the current bicycle baking process, and compounding An appropriate amount of amino curing agent resin can properly reduce the cost of the entire primer; ③ the use of composite anti-rust pigments compounded by modified zinc phosphate, zinc oxide and ion-exchange anti-rust pigments improves the anti-rust effect and is environmentally friendly. The three kinds of pigments used can not only give full play to the antirust effect of each antirust pigment but also have a synergistic effect each other. The three kinds of pigments do not contain heavy metal ions, and their environmental protection meets the Rohs standard and can meet the requirements of the European market; 4. each of the primers of the present invention Reasonable combination of components can better play the role of each component, and the synergy of each component is good, thereby ensuring the performance of the paint film. Carrying out relevant performance test to the paint film of primer of the present invention shows that paint film has excellent corrosion resistance, boiling water resistance and excellent weather resistance and gloss retention, color retention (see Table 4).

Detailed ways

The present invention will be further described in detail below in conjunction with the examples, but not limited thereto.

Unless otherwise specified, the raw materials used in the examples are commercially available industrial products for coatings, and the amounts of the raw materials are in parts by weight.

Embodiment 1 prepares waterborne epoxy acrylic resin

The water-based epoxy acrylic resin is made of epoxy resin with an epoxy equivalent of 500-1500g/mol, which accounts for 10-40% of the total weight of the resin, and is heated and dissolved with a solvent and partially aminated, and then mixed with acrylic acid, hydroxypropyl acrylate, Acrylic resin with an acid value of 50-200mgKOH/g, which is formed by free radical polymerization of butyl acrylate and styrene monomer, is prepared by heating together for catalytic esterification reaction. The specific operation is as follows:

① Preparation of acrylic resin

Add 244 parts by weight of ethylene glycol butyl ether and 90 parts by weight of propylene glycol methyl ether into a 1000ml four-neck flask equipped with a thermometer, a stirring device and a condensation device, start stirring and heat up to a reaction temperature of 115°C, and 92.7 parts by weight of acrylic acid hydroxyl Propyl ester, the acrylic acid of 51.3 parts by weight, the butyl acrylate of 186 parts by weight, the styrene of 155 parts by weight and the benzoyl peroxide of 12 parts by weight were stirred and dissolved evenly, then slowly added dropwise in the above-mentioned four-necked flask, dropwise The addition time is about 4 hours. After the dropwise addition, keep at the reaction temperature of 115°C for 0.5 hours, and then add dropwise a mixture of 3 parts by weight of benzoyl oxide and 75 parts by weight of ethylene glycol butyl ether. The time of dropping is about 1 hour, and finally in the reaction Keep the temperature at 115°C for 2 hours, cool down to stop the reaction, and then produce an acrylic resin with an acid value of 80 mgKOH/g, which is ready for use;

② Preparation of water-based epoxy acrylic resin

The epoxy E-12 resin of 100 weight parts (accounting for 30% of whole resin weight, its epoxy equivalent is 714～1111g/mol) and the ethylene glycol butyl ether of 50 weight parts are joined to thermometer, stirring device and In the 1000ml four-neck flask of the condensing device, start stirring and heat up to the reaction temperature of 120°C to dissolve evenly. At 120°C, add dropwise a mixture of 6.6 parts by weight of diethanolamine and 37.2 parts by weight of ethylene glycol butyl ether for partial amination, drop for 1 hour After adding, keep the temperature for another 2 hours, then add 415 parts by weight of the acrylic resin prepared in ① and 20 parts by weight of the esterification catalyst dimethylethanolamine, react at 120°C for 3 hours, cool down to stop the reaction, and obtain water-based epoxy acrylic acid Resin with a solids content of 55% by weight.

Embodiment 2 prepares water-based closed type polyurethane curing agent resin A and B

(1) The specific formula is shown in Table 1.

Table 1

Note: N75 is 1,6-hexamethylene diisocyanate biuret produced by Bayer; N3390 is 1,6-hexamethylene diisocyanate trimer produced by Bayer.

(2) specific preparation method

According to the formula in Table 1, add polyisocyanate and co-solvent to the reaction vessel and adjust the temperature to 50°C, then add the blocking agent 3,5-dimethylpyrazole, keep the reaction for 2 hours, then raise the temperature to 60-80°C, Add the hydrophilic component dimethylolpropionic acid, keep it warm for 4 hours, then cool down to 50°C, add neutralizing agent dimethylolamine to neutralize, then dilute with deionized water to a solid content of 40% by weight, filter, Packaging respectively made water-based blocked polyurethane curing agent resins A and B, wherein the isocyanate group content of A was 11.7% by weight (solid basis); the isocyanate group content of B was 12.7% by weight (solid basis).

Embodiment 3 prepares bicycle water-based primer

(1) The formula water-based primer for bicycles is composed of the following components, in percentage by weight, and the dosage of each component is as follows:

Water-based epoxy acrylic resin 25-45, curing agent resin 2-10, neutralizer dimethylethanolamine 1-3, composite anti-rust pigment 2-10, coloring pigment and filler 5-20, defoamer 0.1-0.5, Leveling agent 0.1-0.5, deionized water 20-40, the sum of the contents of each component is 100%, the specific formula is shown in Table 2.

Table 2

Note: R717 is an amino resin product of INEOS;

BYK025 is a defoamer product of BYK Chemicals;

BYK331 is the leveling agent product of BYK Chemical Company;

Titanium dioxide 902 is DuPont's rutile titanium dioxide product;

PU carbon black is a carbon black product of Degussa;

ZMP is a modified zinc phosphate anti-rust pigment product of Kaibai Company in Germany;

The ion-exchange anti-rust pigment is a commercially available calcium-exchange silica pigment;

The water-based epoxy acrylic resin in Table 2 can also be replaced by CTW-6018, a product of CNOOC Changzhou Coating Chemical Research Institute, whose epoxy equivalent is 800g/mol, and the epoxy resin accounts for 30% in the total weight of the resin;

(2) Specific preparation process of primer

①In the dispersing kettle, add the water-based epoxy acrylic resin, curing agent resin, neutralizing agent, defoaming agent and leveling agent in the formula amount shown in Table 2, control the speed of the dispersing machine at 400-500 rpm, and stir for 10 minutes After making it evenly mixed, add the deionized water of the formula in Table 2, increase the speed of the disperser to 500-700 rpm, and stir for 15 minutes until the material in the dispersing tank becomes a milky white uniform dispersion;

②Remove half of the milky white homogeneous dispersion prepared in step ① from the dispersing kettle and save it separately, then add the pigments, fillers, and composite anti-rust pigments in the formula in Table 2 to the dispersing kettle, and control the speed of the dispersing machine at 500-800 rpm, stirred for 15 minutes, then increased the speed of the disperser to 1000 rpm, and stirred for 20 minutes to obtain a uniformly dispersed slurry;

③Put the slurry prepared in step ② into a sand mill for grinding. The flow rate of the sand mill is controlled at 4 to 4.5 hours/ton for sand grinding, so that the fineness of the first grinding slurry reaches 45 microns, and the second grinding slurry fineness Reaching 20 microns, that is, meeting the index requirements;

④Put the ground slurry obtained in step ③ into the dispersing kettle, and add half of the milky white uniform dispersion removed in step ② into the dispersing kettle for paint mixing. At this time, the speed of the dispersing machine is controlled at 700-800 rpm , after stirring for 15 minutes, filter with an 80-200-mesh filter screen, pack, and obtain the bicycle water-based primer 1#.

Embodiment 4～6 prepares bicycle water-based primer 2#～4#

(1) The formula is shown in Table 3

table 3

Note: the raw materials are the same as in Table 2;

The water-based epoxy acrylic resin in Table 3 can also be replaced by CTW-6018, a product of CNOOC Changzhou Coating Chemical Research Institute, whose epoxy equivalent is 800g/mol, and the epoxy resin accounts for 30% in the total weight of the resin;

(2) Specific preparation process of primer

Except that the formula is according to Table 3, all the others were made water-based primers for bicycles 2#～4# according to the technique of Example 3.

Comparative example 1 water-based primer

For ease of comparison, the water-based primer formula is basically the same as the water-based primer 1# of embodiment 3, and the difference is: the curing agent resin only uses 75 parts by weight of R717 amino resin; Obtain comparative example 1 water-based primer.

Comparative example 2 water-based primer

For ease of comparison, the water-based primer formula is basically the same as the water-based primer 1# of embodiment 3, and the difference is: replace the water-based acrylic resin of embodiment 3 with 420 parts by weight of water-based acrylic resin (Jiangsu Sanmu Company EA3842 type water-based acrylic resin) Oxygen acrylic resin (embodiment 1 system), the technology of preparing water-based primer is the same as embodiment 3, makes comparative example 2 water-based primer.

Comparative example 3 water-based primer

For ease of comparison, the water-based primer formula is substantially the same as the water-based primer 1# of embodiment 3, and the difference is: a kind of 70 parts by weight of aluminum tripolyphosphate (APW-2 type product of Guangxi Institute of Chemical Industry) replaces embodiment 3 Composite antirust pigments composed of three kinds of pigments; the process for preparing the water-based primer is the same as that of Example 3, and the comparative example 3 water-based primer is prepared.

Embodiment 7 tests the performance of bicycle water-based primer

Test sample: steel plate size 10cm×5cm, after degreasing and polishing the surface, spray water-based primer 1#~4# and the water-based primer of comparative examples 1~3 respectively, first surface dry for 20min, and then bake at 135°C 15min, the dry film thickness is 25±2μm.

According to the relevant national standards of the paint industry, the relevant performance of the above-mentioned samples was tested, and the test results are listed in Table 4 and Table 5.

Table 4

table 5

Note: For the water resistance test in the test items in Table 4 and Table 5 (boiling water resistance for 1 hour, all properties remain unchanged), the "various properties" in it refer to the adhesion of the paint film after boiling water resistance, and the surface resistance of the paint film. Blistering condition.

As can be seen from the test results in Table 4 and Table 5, the bicycle water-based primer 1#～4# prepared by the embodiment of the present invention has a paint film impact resistance of 50 cm, flexibility and adhesion reach grade 1, and pencil hardness 2H, salt spray resistance can reach 240h, meet the EU RoHS standard;

Compared with Comparative Example 1, it can be seen that the present invention adopts the primer prepared by the compounded curing agent resin, and the boiling resistance of the paint film is particularly good, and the properties of the paint film are unchanged for 1 hour after boiling in boiling water;

Compared with Comparative Example 2, it can be seen that the present invention adopts water-based epoxy acrylic resin to make the primer prepared by film-forming resin, and the salt spray resistance performance of its paint film improves;

Compared with Comparative Example 3, it can be seen that the present invention adopts the primer prepared by the composite antirust pigment composed of three kinds of pigments, and the salt spray resistance performance of its paint film is better than only using a kind of traditional aluminum phosphate tripolyphosphate, obviously improving The anti-rust effect of the system.

The components of the water-based primer in the technical solution of the present invention are reasonably matched, and the components have good synergy. Therefore, it has excellent corrosion resistance, boiling water resistance, and excellent weather resistance, gloss retention, and color retention, and is especially suitable for structures such as bicycles. Anti-rust, anti-corrosion.

Claims (4)

1. A water-based primer for bicycles, characterized in that it is made up of the following components, in percentages by weight, and the consumption of each component is as follows: Water-based epoxy acrylic resin 25-45, curing agent resin 2-10, neutralizer dimethylethanolamine 1-3, composite anti-rust pigment 2-10, coloring pigment and filler 5-20, defoamer 0.1-0.5, Leveling agent 0.1-0.5, deionized water 20-40, the sum of the contents of each component is 100%; Described water-based epoxy acrylic resin is epoxy resin modified acrylic resin, and its acrylic resin acid value is 50～200mgKOH/g; The epoxy equivalent of epoxy resin is 500～1500g/mol, and epoxy resin is in resin gross weight 10-40% of the total; The curing agent resin is composed of a water-based closed polyurethane curing agent resin and an amino curing agent resin with a mass ratio of 1:5 to 5:1, wherein the water-based closed polyurethane curing agent resin is unblocked and cured at 130°C, and the amino The curing agent resin is methanol etherified melamine formaldehyde resin or butanol etherified melamine formaldehyde resin; The composite antirust pigment is composed of modified zinc phosphate, zinc oxide and ion exchange antirust pigment. 2. The water-based primer for bicycles according to claim 1, characterized in that, the water-based epoxy acrylic resin is 500-1500g/mol with an epoxy equivalent, and accounts for 10-40% of the epoxy resin in the total weight of the resin. Oxygen resin is heated and dissolved with a solvent and partially aminated, and then heated together with acrylic resin with an acid value of 50-200 mgKOH/g formed by radical polymerization of acrylic acid, hydroxypropyl acrylate, butyl acrylate and styrene monomer Prepared by catalytic esterification reaction. 3. the water-based primer for bicycle according to claim 1, characterized in that, the water-based closed type polyurethane curing agent resin in the curing agent resin is prepared by the following method: in the reaction vessel, add 100 parts by weight of polyisocyanate, ≤25 parts by weight of co-solvent and adjust the temperature to 50°C, then add 10-30 parts by weight of blocking agent 3,5-dimethylpyrazole, keep warm for 2 hours, then heat up to 60-60°C 80°C, add 2-10 parts by weight of the hydrophilic component dimethylolpropionic acid, keep it warm for 4 hours, then cool down to 50°C, add 2-8 parts by weight of neutralizing agent dimethylolamine for neutralization, and then Dilute with deionized water to a solid content of 40% by weight, filter and package to obtain a water-based blocked polyurethane curing agent resin, wherein the polyisocyanate is 1,6-hexamethylene diisocyanate biuret or 1,6-hexamethylene diisocyanate triuretate Polymer. 4. water-based primer for bicycle according to claim 1, is characterized in that, described filler is talcum powder and barium sulfate; Coloring pigment is carbon black and titanium white; Defoamer is BYK chemical company product BYK025, flow The leveling agent is BYK331, a product of BYK; the conductivity of deionized water is ≤20 μs/cm.