CN111117380B

CN111117380B - Water-based primer for automobile plastic parts and preparation method and application thereof

Info

Publication number: CN111117380B
Application number: CN202010005630.3A
Authority: CN
Inventors: 程豪华; 吕楠; 董志磊
Original assignee: Langfang Nippon Paint Co ltd
Current assignee: Langfang Nippon Paint Co ltd
Priority date: 2020-01-03
Filing date: 2020-01-03
Publication date: 2022-06-24
Anticipated expiration: 2040-01-03
Also published as: CN111117380A

Abstract

The invention discloses a water-based primer for automobile plastic parts, which comprises the following raw materials: the water-based chlorinated polyolefin, the water-based polyurethane dispersoid, the water-based blocked isocyanate, the water-based epoxy resin and the modified acrylic emulsion. The water-based primer is environment-friendly, is very suitable for being used in automobile plastic parts, and the formed coating has good comprehensive properties such as adhesion, water resistance, recoatability, constructability, physical and mechanical properties, chemical properties and the like. The invention also discloses a preparation method and application of the water-based primer.

Description

Water-based primer for automobile plastic parts and preparation method and application thereof

Technical Field

The invention relates to the technical field of coatings. More particularly relates to a water-based primer for automobile plastic parts and a preparation method and application thereof.

Background

Plastic parts are used more frequently in automobiles, for example, bumpers for automobiles are mostly made of polypropylene plastic, and the surface tension is low, so that the primer is difficult to wet and adhere, especially the water-based primer. In addition, the plastic parts for automobiles are also required to have good balance of properties such as adhesion, water resistance, recoatability, workability, physical and mechanical properties, chemical properties, and the like. However, the combination of the current water-based primers on the bumper is not good, which is a problem in the field.

Meanwhile, in order to meet the national sustainable green development requirement and the environmental protection requirement of consumers, the development of environment-friendly coating materials has become a mainstream direction for the development of coating products in the future.

Therefore, it is desirable to provide an environmentally friendly water-based primer for automotive plastic parts with a good overall performance.

Disclosure of Invention

In view of the above disadvantages, it is a first object of the present invention to provide a water based primer for automobile plastic parts. The water-based primer is environment-friendly, is very suitable for being used in automobile plastic parts, and the formed coating has good comprehensive properties such as adhesion, water resistance, recoatability, constructability, physical and mechanical properties, chemical properties and the like.

The second purpose of the invention is to provide a preparation method of the water-based primer for the automobile plastic parts.

A third object of the invention is to provide the use of an aqueous primer for automotive plastic parts.

In order to achieve the first purpose, the invention adopts the following technical scheme:

a water-based primer for automobile plastic parts comprises the following raw materials: the water-based chlorinated polyolefin adhesive comprises water-based chlorinated polyolefin, water-based polyurethane dispersoid, water-based blocked isocyanate, water-based epoxy resin and modified acrylic emulsion.

Further, the raw materials of the primer comprise the following components in percentage by weight: 30-40 wt% of waterborne chlorinated polyolefin, 5-15 wt% of waterborne polyurethane dispersoid, 5-10 wt% of waterborne closed isocyanate, 0-5 wt% of waterborne epoxy resin and 5-10 wt% of modified acrylic emulsion.

Further, the aqueous chlorinated polyolefin is aqueous chlorinated polypropylene.

Further, the water-based chlorinated polypropylene is formed by mixing at least two different water-based chlorinated polypropylenes, wherein the solid content of each water-based chlorinated polypropylene is 25-35 wt%, and the chlorine content is 15-20 wt%.

Further, the deblocking temperature of the water-based blocked isocyanate is 100-150 ℃.

Further, the aqueous polyurethane dispersion is an anionic aqueous polyurethane dispersion.

Further, the modified acrylic emulsion is polyurethane modified acrylic emulsion.

Further, the polyurethane modified acrylic emulsion is prepared from polyurethane resin and acrylic emulsion resin through a chemical copolymerization method.

Further, the raw materials of the primer also comprise the following components in percentage by weight: 5 to 10 weight percent of coating additive, 5 to 10 weight percent of pigment filler, 25 to 30 weight percent of deionized water and 5 to 10 weight percent of diluent.

In order to achieve the second purpose, the invention adopts the following technical scheme:

a preparation method of a water-based primer for automobile plastic parts comprises the following steps:

under the condition of stirring, uniformly mixing part of deionized water and part of coating auxiliary agent to obtain a mixture A;

adding pigment and filler, waterborne chlorinated polyolefin and the other part of deionized water into the mixture A, uniformly mixing and grinding the mixture A until the fineness is below 10 mu m to obtain a mixture B;

and adding the modified acrylic emulsion, the aqueous polyurethane dispersion, the diluent, the rest of the coating auxiliary agent and the rest of the deionized water into the mixture B, and uniformly mixing to obtain the aqueous primer.

In order to achieve the third purpose, the invention adopts the following technical scheme:

an application of a water-based primer for automobile plastic parts in coating automobile bumpers.

Furthermore, the material of the automobile plastic part is one or more of ABS, PP/TPO and ABS/PC.

Further, the automobile plastic part is an automobile bumper.

The invention has the following beneficial effects:

the water-based primer for automobile plastic parts provided by the invention is environment-friendly, can meet the coating requirements of various plastic materials such as ABS, PP/TPO base materials, ABS/PC materials and the like, has coating properties such as adhesion, water resistance, recoatability, constructability and the like which are up to or better than those of the traditional solvent-based primer, can be completely used as a replacement product of solvent-based paint, and conforms to the trend of low VOC of automobile paint.

In addition, the water-based primer for automobile plastic parts, provided by the invention, has the great advantages that a changing and washing system does not need to be considered when the bumper line body and other material line bodies are subjected to collinear spraying for the reasons of color cast of the following line bodies such as coating, cost simplification and the like, one line has multiple purposes, multiple types of materials are sprayed together, and the like.

The preparation process provided by the invention is simple, efficient and flexible, can flexibly implement a secondary feeding process according to the actual yield and equipment requirements of a factory, and is very suitable for industrial production.

Detailed Description

In order to more clearly illustrate the invention, the invention is further described below in connection with preferred embodiments. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.

One embodiment of the invention provides a water-based primer for automobile plastic parts, which comprises the following components in raw materials: the water-based chlorinated polyolefin adhesive comprises water-based chlorinated polyolefin, water-based polyurethane dispersoid, water-based blocked isocyanate, water-based epoxy resin and modified acrylic emulsion.

In the technical scheme, the water-based chlorinated polyolefin provides excellent adhesive force, and the water-based chlorinated polyolefin is endowed with good performances of recoating, water resistance, moisture resistance, impact resistance, workability and the like by combining the selection and matching of the water-based polyurethane dispersion, the water-based epoxy resin and the modified acrylic emulsion.

In a preferred example, the raw materials of the water-based primer comprise the following components in percentage by weight: 30-40 wt% of waterborne chlorinated polyolefin, 5-15 wt% of waterborne polyurethane dispersoid, 5-10 wt% of waterborne closed isocyanate, 0-5 wt% of waterborne epoxy resin and 5-10 wt% of modified acrylic emulsion. The addition amount and the proportioning relation of each component are limited, so that the water-based primer with better comprehensive performance can be obtained.

Among the exemplary aqueous chlorinated polyolefins are aqueous chlorinated polypropylenes. Chlorinated polypropylene (CPP) as an adhesion promoter can greatly improve the adhesion between a paint film of the paint and a polypropylene (PP) plastic substrate, the CPP is hydrated to meet the environmental protection requirement and be the direction of research and development of the industry, and the main preparation methods of the CPP emulsion comprise a mechanical method, a chemical modification method and a phase inversion method. The emulsion prepared by a mechanical method has larger grain diameter, wider grain diameter distribution and unstable emulsion performance. The chemical modification method has the defects of various process steps, difficult control, higher cost and the like, and the excellent physical and chemical properties of the CPP are difficult to maintain when the method is used for preparing the water-based chlorinated polypropylene (WCPP, the same below) emulsion. The phase inversion method is suitable for emulsification of high-viscosity resin, the preparation process is relatively simple, the conditions are easy to control, and the obtained water-based emulsion keeps the excellent performance of the CPP resin as an adhesion promoter.

For example, the WCPP is selected from

HARDLEN EW-5515, NV 30 ± 1%, chlorine content 17% and

HARDLEN NZ-1004 of (NV ═ 30 ± 1%), free of chlorine,

HARDLEN EW-5303 or

HARDLEN EH-801 or

The HARDLEN NZ-1015, and the like.

Further, the water-based chlorinated polypropylene is formed by mixing at least two different water-based chlorinated polypropylenes. That is, the aqueous chlorinated polypropylene is a mixture of aqueous chlorinated polypropylene 1 and aqueous chlorinated polypropylene 2 …, wherein n is an integer of 2 or more, preferably 2. The specific mixing ratio is not limited and can be determined according to actual needs.

The respective aqueous chlorinated polypropylene suitable for use in the above embodiments preferably has a solid content of 25% to 35% by weight and a chlorine content of 15% to 20% by weight.

Aqueous polyurethane dispersions (PUD, the same applies hereinafter) can be classified into anionic, cationic and nonionic types, and have the advantages of good adhesion to substrates, good water resistance, recoatability to solvent-borne polyurethane varnishes, compatibility with acrylic emulsions, water-reducible polyesters, WCPO, and the like, so PUD is often used in aqueous coating systemsIs added as a main film forming material or as a functional auxiliary agent. In the embodiment, the PUD is added as the functional resin, and the advantages of outstanding adhesive force, high drying speed, good water resistance and good recoatability are taken, so that the PUD can be used as the functional resin to improve the overall performance of the coating. In a preferred embodiment, the aqueous PUD is selected from the group consisting of anionic type produced by kostew:

UH 2869 with NV of 50 + -1% and pH 6-9, supplied as a 50% aqueous dispersion, or

UH 650 or

UH 2888 or

UH 2757, and the like.

The water-based closed isocyanate can stably coexist with water-based resin (such as water-based polyurethane, water-based acrylate, fluorine emulsion, organic silicon emulsion and the like) for a long time, and when in heat treatment, the product releases isocyanate (-NCO) groups to react with active groups such as hydroxyl, carboxyl, amino and the like on a molecular chain of the water-based resin to form a cross-linked structure, so that various performances of the water-based resin can be obviously improved. In a preferred embodiment, the water-based blocked isocyanate is koste

BL XP 2706, with deblocking temperature of 100 ℃ and 150 ℃, NV of 42 + -2%, pH of 8-9, with a-NCO content after deblocking of 3.6%, supplied as an approximately 42% aqueous solution (neutralized with 2.8pts of dimethylethanolamine).

The waterborne epoxy resin is a stable dispersion system prepared by dispersing the epoxy resin in a dispersion medium taking water as a continuous phase in a form of particles or liquid drops, has extremely high adhesive force to a plurality of substrates, has excellent corrosion resistance and chemical resistance of a cured coating film, has small shrinkage of the coating film, high hardness, good wear resistance, excellent electrical insulating property and the like, is added in a proper amount as functional resin, is environment-friendly, and can improve the performance of a coating. In a preferred embodiment, the waterborne epoxy resin is selected from M6-4400 of NOROO, with NV ═ 25 ± 2.5%, and PH ═ 7-9, and is supplied in a yellow turbid form. In still another preferred example, the content of the water-based epoxy resin in the raw material of the water-based primer is 1 to 5% by mass.

Although the water-based epoxy resin can generate a crosslinking reaction in the presence of free NCO groups at normal temperature, the water-based blocked isocyanate is added into the system, the deblocking temperature is high, and the deblocking can be performed only under the baking condition; the waterborne epoxy resin is not crosslinked at normal temperature, and is not dried at 80-120 ℃ under the condition of no curing agent, while the waterborne primer disclosed by the invention can release free NCO groups at a baking section, so that the curing of the epoxy resin and the combination of-OH on an acrylic chain can be promoted, and the performance of a coating is enhanced.

In a preferred example, the modified acrylic emulsion is a polyurethane modified acrylic emulsion. More preferably, the modified acrylic emulsion is prepared from polyurethane resin and acrylic emulsion resin by a chemical copolymerization method, and due to the unique microphase separation structure of polyurethane, the formed film has excellent mechanical property, wear resistance and low-temperature resistance, and in addition, the glossiness of the formed film and the environmental protection property of the finished emulsion are superior to those of the acrylic resin, but compared with acrylic acid, the cost of the finished emulsion is not superior, and the acrylic emulsion is modified by the polyurethane, so that the advantages of the two properties are complementary; preferably, the modified acrylic emulsion is selected from the group consisting of NOROO N5-1900, NV 40 ± 2%, PH 7.5-9.5, and is supplied in emulsion form.

The water-based primer provided by the embodiment further comprises a coating auxiliary agent, a pigment and filler, deionized water, a diluent and the like contained in the water-based primer.

In a preferred example, the raw materials of the water-based primer further comprise the following components in percentage by weight: 5 to 10 weight percent of coating additive, 5 to 10 weight percent of pigment filler, 25 to 30 weight percent of deionized water and 5 to 10 weight percent of diluent.

The coating auxiliary agent comprises one or more of ultraviolet absorbent, light stabilizer, leveling agent, coupling agent, drier, toughening agent, adhesion promoter, defoaming agent, anti-skinning agent, flatting agent, wetting agent, dispersing agent, thickening agent, antibacterial agent, orientation agent, mildew preventive and antistatic agent.

The wetting and leveling agent can be EVONIK&

SURFYNOL 440, Wet KL 245 and BYK-DYNFET-800N of Pico, Germany, the dispersant being of Pico

(200 KG); the antifoaming agent is digao

SURFYNOL 104, thickening agent is SOLTHIX A100 from Luborun, USA, antibacterial agent is N-ethyl pyrrolidone from Puyang Bright chemical industry, Inc., and orientation agent is AQUATIX 8421 from Pico chemical industry.

Illustratively, the diluent is selected from one or more of ketone solvents, alcohol solvents and alcohol ether solvents.

Illustratively, the ketone solvent is selected from N ethyl pyrrolidone, N methyl pyrrolidone.

Illustratively, the alcohol solvent is selected from one or more of isopropanol, butanol and dipropylene glycol.

Illustratively, the ether solvent is selected from one or more of ethylene glycol butyl ether, dipropylene glycol methyl ether and propylene glycol methyl ether.

In a further preferred example, the paint auxiliary agent comprises 0.1-0.8 wt% of wetting agent, 1-3 wt% of dispersing agent, 0.1-0.5 wt% of leveling agent, 0.3-1.0 wt% of defoaming agent, 0.1-0.5 wt% of thickening agent, 4-5 wt% of antibacterial agent and 0-0.5 wt% of orientation agent in percentage by weight.

In another embodiment of the present invention, there is provided a method for preparing the water based primer for automobile plastic parts as described above, which comprises the steps of:

In a preferred example, the preparation method comprises the steps of:

(1) under the condition of stirring, sequentially adding 5wt% -10wt% of deionized water, 0.1 wt% -0.8 wt% of wetting agent and 1 wt% -3 wt% of dispersing agent into a premixing cylinder, and continuously stirring for 8-15min until the mixture is uniformly stirred;

(2) adding 5-10 wt% of pigment and filler, 30-40 wt% of water-based chlorinated polyolefin and 8-12 wt% of deionized water into the premixing cylinder in the step (1) while stirring, and stirring for 15-20 min;

(3) grinding the premix obtained in the step (2) on a machine until the fineness is less than or equal to 10 microns, transferring the filtrate into a reaction kettle, adding acrylic emulsion, polyurethane dispersion, diluent, other additives, deionized water and the like in a non-grinding section according to the formula ratio, and uniformly mixing; or directly putting the acrylic emulsion, the polyurethane dispersoid, the diluent, other additives, deionized water and the like in the second half section of the formula into a grinding machine in sequence, only circularly mixing without grinding, and filtering after uniformly mixing to obtain the finished product. One process is flexibly selected according to the actual needs of a factory, and the process is simple and efficient.

Exemplarily, in step (1), the stirring speed is: 200-250 r/min; in the step (2), the stirring speed is as follows: 500-600 r/min.

In a further embodiment, the invention provides the use of the above-described water-based primer for automotive plastic parts in the coating of automotive bumpers.

The material of the exemplary automobile plastic part includes but is not limited to one or more of ABS, PP/TPO, ABS/PC. The automotive plastic part may preferably be an automotive bumper (PP).

The technical solution of the present invention is described below with reference to some specific examples:

raw materials:

1. the aqueous chlorinated polypropylene (WCPP) can be selected from

HARDLEN EW-5515 or HARDLEN EW-5303 or HARDLEN EH-801 and HARDLEN NZ-1004 or HARDLEN NZ-1015 are flexibly matched in pairs, and the total amount of matched formulas is proper according to the solid content of each WCPP;

2. the aqueous polyurethane dispersion (PUD) may be selected from the group consisting of the aqueous polyurethane dispersions of Colesine

UH 2869 or

UH 650 or

UH 2888 or

The actual measurement performance of UH 2757 products of the same type reaches the standard;

3. aqueous blocked isocyanates are recommended

BL XP 2706, also can be made domestically in the later stage, but needs further experimental verification;

4. the water-based epoxy resin recommended to use M6-4400 of imported NOROO, has outstanding water resistance, flexibility and the like, and can be localized at a later stage;

5. the modified acrylic emulsion (WPU) recommends using NOROO N5-1900, the branched chain end of the product has more hydrophilicity, can be crosslinked with the deblocked NCO, and is a key functional resin for generating good adhesion to materials such as ABS/PC and the like which are taken as PP;

6. the wetting leveling agent is more, and SURFYNOL 440 with winning wound and height of Di and Wet KL 245 BYNKET-DYNFET-800N with good bike chemistry are recommended;

7. the dispersants are recommended to use Pico chemistry

Or 180, the amount is flexibly added according to the gray level requirement of the primer;

8. the antifoaming agent is SURFYNOL 104 (Digao) or BYK-1710 (BYK-1710) in Bick chemical;

9. the thickener is preferably sold by Sollthix A100 or basf of Luborun

AS 1130；

10. The antibacterial agent is N-ethyl pyrrolidone produced by Puyang Bright chemical industry Co.Ltd;

11. the directional agent is recommended to use AQUATIX 8421 produced by Pico chemistry;

12. the diluent is selected from deionized water produced by Nippon self-production (ED grade), propylene glycol methyl ether produced by Yida chemical industry, dipropylene glycol methyl ether produced by Dow (DOW), dipropylene glycol (DPG) produced by Zhonghai Shell petrochemical company Limited and isopropanol produced by Zhongrong chemical industry;

13. the titanium dioxide is recommended to use medium nuclear titanium dioxide R-2196 or TI-PURE R-960 produced by Kemu chemistry, and the like;

14. the talcum powder is recommended to be 1500 meshes of MICROTALC IT EXTRA-AW PB produced by NOROO or domestic Daqiao talcum powder;

15. the weather silica recommends the use of R-972 or Nipsil SS-50B produced by TOSOH SILICACORPORATION;

16. carbon BLACK is recommended to DENKA BLACK available from Electrochem corporation or special BLACK 4 available from Eurycoma.

Example 1

The water-based primer for automobile plastic parts comprises the following raw materials in a formula shown in the following table 1.

Table 1 weight percent of example 1 feedstock

The preparation method of the water-based primer for the automobile plastic parts comprises the following steps:

A. 7.34 wt% of pure water (ED grade) and 2.29 wt% of dispersant are sequentially mixed

0.76 wt% of a wetting fluid SURFYNOL 104PA was added to the premix cylinder and stirred at 200rpm for 5 minutes;

B. all materials in the auxiliary agent premixing section are sequentially added into another premixing cylinder, a reserved part in 7.86 wt% pure water is used as a transfer washing cylinder, and the materials are stirred at the speed of 200rpm for 5-10 minutes until the materials are uniform for later use;

C. sequentially adding 1.05 wt% MICROTALC IT EXTRA-AW PB, 2.1 wt% Nipsil SS-50B, 3.81 wt% TI-PURE R-960(25kg) and 0.1 wt% DENKA BLACK at the speed of 200 rpm; adding a proper amount of varnish cylinder wall from 11.34 wt% of pure water (ED grade) after the pigment and filler are added;

D. adding 15.73 wt% of HARDLEN NZ-1004 and 14.49 wt% of HARDLEN EW-5515 functional resin at the speed of 200rpm, and stirring at the speed of 500rpm for 20 min;

E. transferring the grinding stage premix (A) to a grinder and washing the premix cylinder with pure water (ED stage) remaining from (C) 11.34% wt%;

F. grinding to fineness less than or equal to 10 μ M, and adding 6.58 wt% of N5-1900, 2.38 wt% of M6-4400 and 5.05 wt% of BAYHYDROL UH 2869 of functional resin and the premixed solution in the step (B) into a grinder for circulation without grinding;

G. and putting the washing machine liquid into a washing machine, filtering to obtain an initial product, and properly adjusting the viscosity of the initial product by using viscosity-adjusting SOLTHIX A100 or pure water according to requirements to prepare the water-based primer.

Comparative example 1

The primer was prepared by replacing the WCPO with only equal weight as compared to example 1, replacing the WCPO of the examples with a single WCPO.

Comparative example 2

In contrast to example 1, only equal weights were used instead of other commercially available aqueous polyurethane dispersion types, for example: commercially available from Coltsingchu's BAYHYDROL U2757, Lamberti

PU 62 was prepared to obtain a primer.

Comparative example 3

In contrast to example 1, a primer was prepared without addition of only the aqueous blocked isocyanate.

Comparative example 4

In contrast to example 1, a primer was prepared without the addition of the modified acrylic emulsion.

Single-coating and composite-coating plate making and performance verification

The test aims at simulating the performance of normal primary workpieces and returned workpieces on a production line, and the placing time of a single-coating test board is divided into: 7 days at normal temperature, and one month at normal temperature; the single-coating board manufacturing process is 3C2B, the pre-drying condition of primer at 70-80 ℃ for 10min is adopted, the flash drying time of colored paint and varnish is 8min, and the varnish is put into an oven at 80 ℃ for 40min and then taken out after being sprayed. The aging conditions of the single coating and the composite coating are as follows: 60 ℃ for 2 days or 80 ℃ for 12 h; the test items and methods are shown in table 2 below. The corresponding properties of the varnishes obtained in example 1 and comparative examples 1 to 4 are shown in Table 3 below.

TABLE 2 coating Key test items and test methods

Table 3 comparison of the performance tests of the examples with those of the comparative examples

From the comparative example 3 performance results in table 3, it can be seen that: no water-based closed isocyanate is added, and the performances of the water-based closed isocyanate are NG no matter the water-based closed isocyanate is water-resistant, moisture-resistant, flushing water and circulating on PP/TPO or ABS/PC materials; therefore, the functional resin has great help to the performances of moisture resistance, water resistance and the like; as can be seen in comparative example 4 in which the modified acrylic emulsion was not added, the TPO material was normal in performance except that the water resistance, moisture resistance, flushing resistance and the like were exhibited in the NG on ABS/PC; the WCPO modified chain end also has adhesive force to ABS/PC material, and the adhesive force is not strong after modified acrylic emulsion is added, so that the WCPO modified chain end has certain universality on a production line; as can be seen from comparative example 2, the preferred PUD is of great help in terms of re-paintability and finger-snap resistance of the product and is of great importance for on-site reworked products of the product; from comparative example 1, it can be concluded that the reasonable collocation of the preferred WCPO is the key to determining performance; the conventional WCPO is generally poor in low-temperature storage, easy to flocculate and poor in compatibility; the selected modified CPO, such as WM-CPO (waterborne maleic acid modified chlorinated polypropylene), can not only increase the adhesion of the product to a substrate and the interlayer compatibility, but also has excellent performance in low-temperature storage, and even has great help on the adhesion to ABS materials.

Example 2

The water-based primer for automobile plastic parts has the following raw material composition formula shown in the following table 4.

TABLE 4 Components and contents (parts by weight/100 parts) of example 2

(1) 65.58 parts of the semi-finished base material W1 from the grinding and washing stages of example 1 were charged into a premix cylinder and the subsequent examples were tested in this manner to reduce the time and system errors associated with each set of tests.

(2) Respectively adding modified acrylic emulsion N5-19006.49 parts, waterborne epoxy resin M6-44004.70 parts, PUD 4.98 parts and waterborne HDI XP 27064.70 parts into a premixing cylinder in the step (1); 13.54 parts of wetting and leveling agent, bactericide, directing agent and deionized water; uniformly mixing and stirring to obtain the high-performance water-based primer; according to the actual standard, deionized water or a proper amount of thickener SOLHIX A100 is used for adjusting the viscosity.

(3) Example 2 differs in that the content of the aqueous epoxy resin is increased and the influence on the water resistance, moisture resistance, surface drying and the like is examined.

Example 3

The water-based primer for automobile plastic parts has the following raw material composition formula shown in the following table 5.

Table 5 example 3 components and parts by weight (parts by weight/100 parts)

(1) 64.07 parts of semi-finished base material W1 prepared in the grinding section and the washing section of example 1 is put into a premixing cylinder; respectively adding modified acrylic emulsion N5-19004.59 parts, waterborne epoxy resin M6-44006.34 parts, PUD2.30 parts and waterborne HDI XP 27064.87 parts into a premixing cylinder in the step (1); 17.61 parts of wetting and leveling agent, bactericide, directing agent and deionized water; uniformly mixing and stirring to obtain the high-performance water-based primer; according to the actual standard, deionized water or a proper amount of thickener SOLHIX A100 is used for adjusting the viscosity.

(2) Example 3 differs in that the content of the aqueous polyurethane dispersion was increased and the effect on the properties of recoat adhesion, finger grip resistance, water resistance, moisture resistance, etc. was examined.

Example 4

The water-based primer for automobile plastic parts has the following raw material composition formula shown in the following table 6.

TABLE 6 example 4 Components and parts by weight (parts by weight/100 parts)

(1) 64.07 parts of semi-finished base material W1 prepared in the grinding section and the washing section of example 1 is put into a premixing cylinder; respectively adding HARDLEN EW-55154.59 parts of waterborne chlorinated polypropylene, N5-19006.34 parts of modified acrylic emulsion, M6-44002.3 parts of waterborne epoxy resin, 4.87 parts of PUD and 27064.59 parts of waterborne HDI XP into a premixing cylinder in the step (1); 13.24 parts of wetting and leveling agent, bactericide, directing agent and deionized water; uniformly mixing and stirring to obtain the high-performance water-based primer; according to the actual standard, deionized water or a proper amount of thickener SOLHIX A100 is used for adjusting the viscosity.

(2) Example 4 is distinguished by increasing the content of the aqueous chlorinated polypropylene, and investigating the effects on the adhesion of PP/TPO substrates, water resistance, moisture resistance, damp-heat high and low temperature cycles, and related properties.

Example 5

Example 5 the process of example 2 was the same except that the PUD described in example 5 was changed to

UH 2888, added in the same amount as in example 2.

Example 6

The water-based primer for the automobile plastic parts comprises the following raw materials in a formula shown in the following table 7.

Table 7 example 6 components and their weight percent content

The preparation method of the water-based primer for the automobile plastic part comprises the following steps:

(1) example 6 the process of example 1 is the same except that the WCPO of example 6 is changed from the original HARDLEN NZ-1004 to HARDLEN NZ-1015 in the same weight parts;

(2) example 6 is intended to examine the effect of adhesion, water resistance, moisture resistance, hot and humid high and low temperature cycles, and related properties on PP/TPO substrates on the adhesion of the substrates.

The aqueous varnishes obtained in examples 2 to 6 were tested for their properties in the manner described above in Table 2, and the results are shown in Table 8 below.

Table 8 results of performance testing of examples

Based on the above description, it is necessary to adjust, replace or even discard some raw materials, such as modified acrylic emulsion, or orientation agent or other materials, according to the actual needs (e.g., some factories do not need collinear spraying or for reasons of productivity, cost, etc.), without affecting the performance of the bumper.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications may be included within the scope of the present invention.

Claims

1. The water-based primer for the automobile plastic parts is characterized in that the primer comprises the following components in percentage by weight: 30-40 wt% of waterborne chlorinated polyolefin, 5-15 wt% of waterborne polyurethane dispersoid, 5-10 wt% of waterborne closed isocyanate, 1-5 wt% of waterborne epoxy resin and 5-10 wt% of modified acrylic emulsion;

wherein the aqueous chlorinated polyolefin is selected from TOYOBO^®HARDLEN EW-5515 or HARDLEN EW-5303 or HARDLEN EH-801 and one of HARDLEN NZ-1004 or HARDLEN NZ-1015;

the aqueous polyurethane dispersion is selected from Bayhydrol UH 2869, NV =50 +/-1%, p H value 6-9, and is in the form of 50% aqueous dispersion or Bayhydrol UH 650 or Bayhydrol UH 2888.

2. The water-based primer according to claim 1, wherein the water-based blocked isocyanate has a deblocking temperature of 100-150 ℃.

3. The waterborne primer of claim 1, wherein the modified acrylic emulsion is a polyurethane modified acrylic emulsion.

4. The water-based primer according to claim 3, wherein the polyurethane modified acrylic emulsion is prepared by chemically copolymerizing a polyurethane resin and an acrylic emulsion resin.

5. The water-based primer according to claim 1, wherein the primer comprises the following raw materials in percentage by weight: 5 to 10 weight percent of coating additive, 5 to 10 weight percent of pigment filler, 25 to 30 weight percent of deionized water and 5 to 10 weight percent of diluent.

6. A method of forming a waterborne primer according to any one of claims 1-5 comprising the steps of:

7. Use of an aqueous primer according to any one of claims 1 to 5 for the coating of automotive bumpers.

8. The use of claim 7, wherein the material of the automotive plastic part is one or more of ABS, PP/TPO, ABS/PC.

9. The use of claim 7, wherein the automotive plastic part is an automotive bumper.