KR100666776B1 - Sealer composition for body penel reinforcement of automobile - Google Patents

Abstract

Provided is a two-part sealer composition as a reinforcing agent for a steel sheet, which is semi-cured at room temperature to prevent deformation of a car steel sheet, shows no flowing property even after 3 days, and has excellent mechanical properties including impact resistance and corrosion resistance. The two-part sealer composition as a reinforcing agent for a steel sheet comprises: a base comprising 25-70 wt% of an epoxy resin, 5-10 wt% of a polyester resin, 5-10 wt% of a liquid rubber resin, and 11-50 wt% of additives containing at least one selected from fillers, accelerators, anti-aging agents, flame retardants, thixotropic agents and coupling agents; and a curing agent comprising 30-70 wt% of an aliphatic polyamide and 30-70 wt% of fillers, the base and the curing agent being mixed in a weight ratio of 2:1-8:7.

Description

Sealant composition for body penel reinforcement of automobile

The present invention relates to a two-part steel sheet reinforcement sealer composition, and more particularly, to an additive containing epoxy resin, polyester resin, liquid rubber additive and filler, accelerator, anti-aging agent, flame retardant, thixotropic agent and coupling agent. The steel sheet reinforcement composition prepared by mixing the hardener composed of the main body and the aliphatic polyamide and the filler at the optimum ratio is semi-cured at room temperature to prevent the shrinkage of the sealer to prevent deformation of the automotive steel sheet, and even when left at room temperature for 3 days or more The present invention relates to a two-part steel sheet reinforcement sealer composition having no flowability due to moisture absorption and having excellent mechanical properties such as impact resistance and corrosion resistance, thereby improving shear adhesion when applied to automotive steel sheets.

In general, in order to obtain physical properties such as impact resistance and cracks during the vehicle assembly process, a process of coating a steel plate reinforcement (BPR) sealer composition on a steel sheet is performed. The steel sheet reinforcement sealer composition is pressurized by a pressure pump and transferred through a pipe, and then subjected to a process of applying through a coating gun and a nozzle according to the specifications required for the steel sheet and curing after passing the conditions of the automobile coating line. The strength is exerted.

Recently, the amount of the reinforcing sealer composition is rapidly increasing, which acts as a major factor in the increase in manufacturing cost. Therefore, reduction of the coating thickness by increasing the material strength has been studied. Existing reinforcing agents can increase the rigidity by increasing the amount of hardening agent, but there is a problem of slight coating thickness variation or deformation of the board at low temperatures (Dent). There is a problem of deterioration and reduction of shelf life.

Conventional automotive steel reinforcement is a one-component type in which epoxy resin and hardener are present together in the sealer's composition, and there is a problem of outer plate bending due to shrinkage during high temperature curing. It was not possible to apply the product, and the problem of the flow of the product occurred in the waiting period of more than 3 days due to the influence of moisture due to long-term neglect during summer holidays or vacations in the automobile production line.

Thus, the present inventors have tried to solve the flow problems due to the deformation of the outer plate of the conventional one-piece steel sheet reinforcement and the foaming caused by moisture.

As a result, the curing agent composed of an epoxy resin, polyester resin, liquid rubber additives, additives such as fillers, accelerators, anti-aging agents, flame retardants, thixotropic agents and coupling agents, and a curing agent composed of aliphatic polyamides and fillers The steel sheet reinforcement composition manufactured by mixing in a ratio is a two-component composition that is semi-cured at room temperature by mixing a main ingredient and a curing agent to prevent moisture absorption, thereby improving flowability due to bubble generation and preventing shrinkage of the sealer. The present invention was completed by removing the deformation of the steel sheet and increasing mechanical properties such as impact resistance and corrosion resistance.

Accordingly, an object of the present invention is to provide a two-component sealer composition having improved flowability, impact resistance, corrosion resistance, and the like.

The present invention is a two-component steel sheet reinforcement sealer composition,

(a) 25 to 70% by weight epoxy resin, (b) 5 to 10% by weight polyester resin, (c) 5 to 10% by weight liquid rubber resin, and (d) fillers, accelerators, antioxidants, flame retardants, thixotropic A subject composed of 11 to 50% by weight of an additive which is one or a mixture of two or more selected from tropic agents and coupling agents,

Curing agent composed of 30 to 70% by weight of aliphatic polyamide and 30 to 70% by weight of filler

It is characterized by a two-part steel sheet reinforcement sealer composition, characterized in that the 2: 1 to 8: 7: weight ratio range.

The present invention will be described in more detail as follows.

The present invention is a sealer composition in which Resin and a curing agent are mixed in a specific component ratio.

The main agent, which is the first agent used in the present invention, has an epoxy resin as a main component, and the epoxy resin is specifically a bisphenol A-type epoxy for rigidity, a dimer-modified epoxy for increasing adhesion with an adhesive, a rubber for obtaining cold shock resistance. One or a mixture of two or more selected from the modified epoxy may be used. The epoxy resin is used in the range of 25 to 70% by weight, preferably in the range of 30 to 50% by weight, and when used in less than 25% by weight, workability problems due to viscosity increase and rigidity such as adhesive strength and flexural strength. It causes a decrease, the viscosity is too low when used in excess of 70% by weight, there is a workability problem and a problem that the shrinkage rate is increased according to the increase in strength.

The polyester resin has characteristics that complement the problems of cold shock resistance and shrinkage rate, and used in the range of 5 to 10% by weight, cold resistance when the use is less than 5% by weight and cold resistance worsens, and flexural strength when it exceeds 10% by weight. Problems of flowability occur after degradation and moisture resistance.

The liquid rubber resin serves to improve the impact resistance and deformation resistance by increasing the elasticity of the composition, and specifically, one or a mixture of two or more selected from dimer-modified epoxy and rubber-modified epoxy is used. It is used in the range of 5 to 10% by weight, high rigidity when using less than 5% by weight, the phenomenon of shrinkage of the steel sheet and low strength when more than 10% by weight occurs a problem that lacks the required rigidity of the steel sheet.

The additive uses one or two or more selected from fillers, accelerators, anti-aging agents, flame retardants, thixotropic agents, and coupling agents. The additive is used in the range of 11 to 50% by weight, preferably in the range of 15 to 45% by weight, and when used in less than 11% by weight, there is a problem of flowability due to low shrinkage phenomenon and viscosity due to heat resistance and more than 50% by weight. Therefore, when used, the viscosity is high, and also the strength is high, the impact problem occurs.

In addition, conventional additives used in the art may be added.

In the present invention, a curing agent as a second agent is used, and a composition mainly composed of epoxy depends on the properties of the cured product, the curing speed, adhesive strength, and strength, and the curing agent as the second agent used in the present invention is an aliphatic poly having aromatic group properties. The amide is used in the range of 30 to 70% by weight, preferably in the range of 35 to 65% by weight, and when used less than 30% by weight, the strength decreases while being uncured, and when the strength exceeds 70% by weight, the steel sheet There is a problem of deformation.

The filler has the property of suppressing the occurrence of shrinkage and bending, specifically, using one or two or more selected from calcium carbonate, silica, wollastonite, etc., the filler is used in the range of 30 to 70% by weight, Preferably it is used in the range of 40 to 60% by weight, when using less than 30% by weight is difficult to supplement the viscosity, there is a problem that the flow occurs, and when more than 70% by weight the viscosity is too high and the lack of flexural strength occurs.

The first agent and the second agent, which are the above-mentioned subjects, are mixed and used in a weight ratio of 2: 1 to 8: 7, and when used in a weight ratio of less than 2: 1, problems of insufficient curing occur and strength when the weight ratio exceeds 8: 7 There is a problem that the shrinkage rate increases with the increase.

Mixing of the main material and the curing agent is generally used in the art, but is not particularly limited. However, it is preferable to mix the main material or the curing agent sufficiently to have a uniform composition using the same mixer. The main component and the hardener are mixed at a weight ratio of 2 to 1 to 8 to 7 using a two-component apparatus under 25 to 35 ° C. and room temperature conditions to complete a two-component steel reinforcement sealer composition.

Hereinafter, the present invention will be described in more detail based on the following examples, but the present invention is not limited to the examples.

In the examples and comparative examples, the symbol means the following contents.

1. Subject

1) epoxy resin

① E-1: Bisphenol A type epoxy

② E-2: dimer modified epoxy

2) Polyester resin (P): ethylene glycol

3) Rubber resin (R): NBR modified epoxy

4) additive

① Filler (F): calcium carbonate

② accelerator (A): imidazole modified

③ Anti aging agent (O): epoxy soybean oil

④ flame retardant (S): metal-based flame retardant

⑤ thixotropic agent (T): fumed silica

⑥ coupling agent (C): an organosilicon compound

2. Second agent (curing agent)

1) aliphatic polyamide (PA): aliphatic diamine including aromatic group

2) Filler (F): calcium carbonate

Example 1

The main body is made by mixing each component under 60 ° C. according to the component ratios shown in Table 1, the hardener is mixed under 60 ° C. according to the component ratios shown in Table 1, and then the main body and the curing agent are mixed at a weight ratio of 100: 55. The composition was prepared, and the prepared composition was subjected to a performance test through MS-721-60, and the results are shown in Table 2.

Example 2

Prepared in the same manner as in Example 1, but after the main body and the curing agent was prepared to prepare a composition by varying the mixing ratio in a 100: 50 weight ratio, and the performance of the prepared composition through the MS-721-60 to test the results 2 is shown.

Comparative Example 1

Prepared in the same manner as in Example 1, but after the main body and the curing agent was prepared to prepare a composition by varying the mixing ratio in a weight ratio of 100: 40, and tested the performance of the prepared composition through the MS-721-60 test results Table 2 shows.

Comparative Examples 2 to 4

To prepare a composition in the same manner as in Example, Comparative Example 2 was prepared by mixing the main body and the curing agent in a 100: 50 weight ratio, except for the polyester resin, Comparative Example 3 was prepared without the liquid rubber resin The curing agent was mixed and prepared in a weight ratio of 100: 50, and Comparative Example 4 prepared the composition by excluding the polyester resin and the liquid rubber resin, followed by MS-721-60 test in the same manner as in Example. Indicated.

Division (weight%) Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 subject Epoxy resin To-1 30 30 30 35 35 35 E-2 20 20 20 20 23 28 P 5 5 5 - 5 - R 8 8 8 8 - - additive F 15 15 15 15 15 15 A 14 14 14 14 14 14 O 2 2 2 2 2 2 S 5 5 5 5 5 5 T 0.5 0.5 0.5 0.5 0.5 0.5 C 0.5 0.5 0.5 0.5 0.5 0.5 Hardener PA 50 60 70 50 60 70 F 50 40 30 50 40 30

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Adhesive strength (kg / ㎠) 184 172 167 162 158 150 Flexural strength (kg) 5.6 5.3 5.2 4.8 4.5 4.2 Volume change rate (%) 0 0 0 0.15 0.2 0.25 Cold resistance (times) 20 times 20 times 20 times 15 10 6 Flowability (30 ℃, 4 hours) clear clear clear 0.5mm 2 mm 2.5mm Flowability (163 ℃, 20 minutes) clear clear clear 1 mm 2.5mm 3 mm

<Test method>

1) Apply the composition 75 x 150 x 4.6 mm thick on a 100 x 300 mm specimen.

2) Place the steel plate vertically for 4 hours at room temperature, and observe the flow of the sealer, deflection, and movement from its original position and record the result.

3) After completion of the test, place the steel plate vertically in a hot air drying oven and cure at 163 ° C for 20 minutes.

4) Record the results by observing the flow of the sealer, deflection, and movement from its original position.

As can be seen in Table 2, the two-component sealer compositions of Examples 1 to 2 are excellent in flowability, and the compositions of Comparative Examples 1 to 4 can be confirmed that the flowability and cold resistance are largely inferior.

As described above, according to the present invention, the two-component sealer composition has a property of greatly improving flowability, satisfying impact resistance and corrosion resistance at the same time, and solving the problem of deformation of the outer plate of the steel sheet. After mixing and semi-curing at room temperature, heat curing was remarkably improved, and the shrinkage of the material was remarkably improved. By preventing moisture absorption in the semi-curing state at room temperature, the flowability caused by bubble generation was improved, which can be used for reinforcing steel sheet of automobile. have.

Claims (3)

In the two-component steel sheet reinforcement sealer composition, (a) 25 to 70% by weight epoxy resin, (b) 5 to 10% by weight polyester resin, (c) 5 to 10% by weight liquid rubber resin, and (d) fillers, accelerators, antioxidants, flame retardants, thixotropic A subject composed of 11 to 50% by weight of an additive which is one or a mixture of two or more selected from tropic agents and coupling agents, Curing agent composed of 30 to 70% by weight of aliphatic polyamide and 30 to 70% by weight of filler 2: 1 to 8: 7 Two-part steel sheet reinforcement sealer composition, characterized in that consisting of a weight ratio range. The two-part steel sheet reinforcement composition according to claim 1, wherein the epoxy resin is one or a mixture of two or more selected from dimer-modified epoxy, bisphenol A-type epoxy, and polyester resin. The two-part steel sheet reinforcement composition according to claim 1, wherein the rubber resin is one or a mixture of two or more selected from rubber-modified epoxy and liquid rubber.