KR100763409B1 - Structural Adhesive Sealer Composition for Metal Bonding using Recycled Waste Paint - Google Patents

Abstract

The present invention relates to a structural adhesive sealer composition for metal bonding containing waste paint in the automotive and electronic component industries, and more particularly, functional activators remaining in the waste paint (-COOH, -OH, -NH2, etc.). The waste paint powder produced by the physicochemical hybrid dehydration method can be preserved as it is not lost during the water dehydration process, and it has the miscibility, dispersibility, and reactivity in the resin to replace the epoxy recycled resin (alternative efficiency: 50% by weight). The present invention relates to a structural adhesive sealer composition for metal bonding using the same. For the present invention, the mixing ratio of the epoxidized soybean oil modified bifunctional epoxy and waste paint powder (particle size: 5-50 μm, water content: <5%) prepared by the physicochemical hybrid dehydration method is 1: 1 by weight. The resin is composed of a hardener, a curing accelerator, a rubber polymer, a surfactant, a plasticizer, a heat stabilizer, a flow inhibitor, and an inorganic filler in the main resin, and in particular, the automobile body steel joints or joints (DOOR HINGE REINFORCE, ROOF RAIL, FRONT PILLAR REINFORCE and the like, and a heat-curable one-component structural adhesive sealer composition capable of replacing waste paint resin up to 50% by weight.

Structural Adhesive Sealer, Waste Paint Powder, Epoxidized Soybean Oil Modified Epoxy, Alternative Recycled Resin

Description

Structural Adhesive Sealer Composition for Metal Bonding using Recycled Waste Paint}

Figure 1 is a predicted bond shape between the resin upon mixing of the active group-containing waste paint powder and epoxy resin according to the present invention

2 is a measurement result of the glass transition temperature (Tg) change according to the amount of recycled waste paint added

The present invention relates to a structural adhesive sealer composition for metal bonding using recycled waste paint generated in the coating process of the automobile and electronic parts industry as a functional material, and more particularly, epoxidized soybean oil modified bifunctional epoxy and physicochemical hybrid. The main resin is constituted so that the mixing ratio of the waste paint powder (particle size: 5-50 µm, water content: <5%) prepared by the dehydration method is 1: 1 by weight, and the curing agent, the curing accelerator, the rubber polymer, and the surfactant are described above. , Plasticizer, heat stabilizer, flow inhibitor, inorganic filler, especially for automobile body steel joints or joints (DOOR HINGE REINFORCE, ROOF RAIL, FRONT PILLAR REINFORCE, etc.) It relates to a heat-curable one-component structural adhesive sealer composition capable of up to 50% by weight.

The waste paint powder used in the present invention is prepared according to the "method of preparing an active group-containing waste paint powder using hybrid dehydration method" of Application No. 10-2005-0005704 (-COOH, -OH, -NH2, etc.) ) Is compatible with the main resin because it has miscibility and reactivity, the effect of replacing the main resin of the structural bonding sealer composition for metal bonding in use conventionally. The main reason why the technology using the conventional waste paint recycling material is not activated is mainly researching the manufacture of low-use recycled paint using waste paint before solidification in the painting process, or researching the inert powder material by simple physical dehydration and incineration. Because I came. This inert recycled material is used as a general purpose to replace the low-cost inorganic fillers because it is less economical and less demanding applications, causing the reduction of the paint waste reduction effect through recycling. For this reason, the structural adhesive sealer composition containing the active group present waste paint powder proposed in the present invention is differentiated from the prior art because it is intended to replace expensive resin as a main raw material.

The one-component structural adhesive sealer is widely used to bond metal parts in various industries that require high strength, and is widely used in the automobile industry to be used together with spot welding or to bind joints alone. The use of structural adhesive sealers is increasing due to the replacement of and the increase of working speed.

Conventionally, the structural adhesive sealer for metal bonding can satisfy the required adhesive stiffness when expensive epoxy resins contain at least about 40 to 50% by weight of the total composition in order to develop mechanical strength. I have a problem.

In addition, the structural adhesive sealer hardening process for automobiles is performed with two to four coating processes at high temperatures of 150-220 ° C, so that stable physical properties must be expressed without cracking or peeling of the sealer under the coating conditions. When a physical vibration or impact is applied, the sealer composition interposed between the layers of the metal sheet expresses a flexible characteristic, so that a durable sealer is required in the actual vehicle use.

Accordingly, the present invention is to solve the conventional problems as described above, the epoxidized soybean oil modified bifunctional epoxy as the main resin as a Daesung matrix resin, according to the application No. 10-2005-0005704 "containing the active group using the hybrid dehydration method Recycling waste paint powder manufactured by “Recycling waste paint powder” was added to the hard epoxy resin by adding recycled waste paint made of polyurethane and modified acrylic resin as soft segment to ensure flexibility. It is an object to provide a composition and a method of applying waste paint powder.

Another object of the present invention is to apply the active resin-containing recycled waste paint powder as a main resin substitute material to achieve the 50% by weight of the epoxy resin replacement efficiency (100% by weight of waste paint compared to the epoxy) of the sealer components of the structural adhesive sealer In order to meet the physical properties and at the same time improve the waste paint recycling, to solve the conventional problems.

The present invention modified the bifunctional epoxy into epoxidized soybean oil as a main resin to give flexibility through internal plasticization, and design a sealer composition to control the crosslinking density by finely dispersing the recycled waste paint powder of linear polymer in the main resin It was. Here, as an additive for improving physical properties, 5 to 10% by weight of the curing accelerator compared to the main resin, 10 to 40% by weight of the rubber polymer, 0.5 to 3% by weight of the surfactant, 5 to 20% by weight of the plasticizer, 0.5 to 5% by weight of the heat stabilizer, 1 to 5% by weight of flow inhibitors may be further included.

For the preparation of the waste paint powder containing the active group, the following preparation method was used, as shown in Application No. 10-2005-0005704. As a chemical dehydration adjuvant, calcium sulfate, magnesium sulfate, calcium chloride, calcium carbonate, aluminum oxide, calcium oxide, active carbon, bentonite, zeolite are used as chemical dehydration aids to prevent the loss of functional active groups remaining in the dehydration and drying process. Alternatively, at least one or more of these mixtures may be selected to add 5 to 20% by weight relative to the solids in the waste paint, and the water in the waste paint is first removed by a hybrid dehydration method using a physical pressurized dehydrator. After the paint is mixed with the chemical dehydration adjuvant, the water is removed secondarily by the vacuum drying method under the temperature condition of about 50 ~ 100 ℃, and the waste paint is crushed under the temperature condition of about 50 ~ 80 ℃. An active group-containing waste paint powder production method having a water content of 5% or less and a 50 μm particle size was used.

Hereinafter, the detailed description and examples of the composition according to the present invention are as follows.

Epoxy used in the present invention is added to the epoxy resin selected from the epoxy resin of the diglycidyl ether type bisphenol A and bisphenol F to 15% by weight or less compared to the resin to 30 ~ 60 at 100 ~ 120 ℃ under nitrogen conditions Stir for a minute. In the present invention, the recycled waste paint powder is blended with the above-mentioned epoxy resin in a mixed weight ratio of 1: 1, and the amount of waste paint powder used in the total composition reaches 20 to 45% by weight. At this time, when the amount of recycled waste paint powder is less than the above range, the adhesive strength and impact strength are lowered. On the other hand, when the recycled waste paint powder is used, the dispersibility in the epoxy resin is poor due to problems such as wettability and high / liquid ratio. Physical properties are lowered.

In the embodiment of the present invention was used waste paint powder having the characteristics of the epoxy (Formula 1) and polyurethane (PU) resin as shown in Formula 2, and the resin-bonded form as shown in Figure 1 due to the mixing of the two resins It is believed to represent.

Here, the waste paint powder used in the present invention is maintained so that resin components such as urethane and modified acrylic, which are the main components of the waste paint, are not lost by the heat curing reaction during drying and dehydration. Thus, as shown in FIG. As the amount added increases, the glass transition temperature is lowered to improve low temperature impact properties.

In addition, 0.5 to 3 wt% and 5 to 20 wt% of sodium dodecyl sulfonate, a surfactant, and a plasticizer, dioctyl adipate, are added and mixed to the main resin to make uniform dispersion. Used.

In addition, as the rubber polymer used in the present invention, carboxyl terminated butadiene acrylonitrile (CTBN), acrylonitrile butadiene rubber (NBR), styrene butadiene rubber (SBR) and the like may be used to improve impact resistance. When the amount of the rubber is used 10 to 40% by weight compared to the main resin and less than 10% by weight, the residual adhesion rate of the adhesive fracture cross-section is less than 70%, while if more than 40% by weight may cause problems in workability due to high viscosity have.

In addition, in the present invention, 5 to 10% by weight of diuron was added to the main resin as a curing accelerator in order to compensate for the high curing temperature of the dicyandiamide as a curing agent. When the curing temperature is lower than 40 ℃ compared to 150 ℃ curing temperature was confirmed that, when added less than 5% by weight does not change the overall curing reaction, crosslinking is loosened when added more than 10% by weight This is because diuron reacts at both ends of the four active hydrogens that the dicyandiamide provides to the epoxy resin, thereby preventing continuous bonding.

In general, calcium deoxygenation and talc fillers, which are mainly used in epoxy sealers, may be used in an amount of 50 to 100% by weight compared to the main resin, and when used less than 50% by weight lower than the above range, there is a problem that the adhesive strength is lower than the required properties. When added to 100% by weight or more, there is a problem that the impact resistance is low because the flexibility of the cured product is low. In addition, bentonite and carbon black may be added in an amount of 0.5 to 2 wt% based on the main resin to improve workability.

Since the hardening process of the structural adhesive sealer to be developed is performed with 2 ~ 4 times of coating process at high temperature of 150 ~ 220 ℃, it should express stable physical properties without crack or peeling of the sealer under the above coating condition. Therefore, in the present invention, 0.5 to 5% by weight of a mixture of beta-diketone and stearoylbenzomethane is used as a heat stabilizer for heat resistance of the structural adhesive sealer.

When the recycled waste paint powder is added, the viscosity of the sealer can be increased to reduce the use of expensive flow inhibitors, but the dimensional stability is necessary because the flow may be caused by impact during thermal curing during the continuous process. Therefore, the flow inhibitor adds 1 to 5% by weight of fumed silica to impart thixotropy to the composition. If it is added in the range of 1% by weight or less, there may be a problem that the structural adhesive sealer flows without filling in the joining part during the curing process, and when more than 5% by weight is added, the viscosity increases more than necessary so that the structural adhesive sealer is sprayed. Difficulty in controlling the discharge amount may occur when applying.

In addition, since the structural adhesive sealer used for automobile metal parts is a one-component adhesive, the curing conditions are made at a high temperature of 150 ° C. or higher, and dicyaned diamide, a heat latent curing agent suitable for the above conditions and excellent storage stability, is epoxidized soybean oil-modified epoxy. Can be used 5 to 10% by weight compared to the resin, and substituted dicyanamide with aniline derivatives to increase the compatibility of the resin and the curing agent, and promoted dicyanamide mixed with an accelerator to increase the reaction rate can be used according to the purpose. have. The curing reaction of the diglycidyl ether type epoxy resin and dicyanamide used in the present invention is as shown in the formula (3).

Although the physical property evaluation of the recycled waste paint powder sliding structure adhesive sealer composed of the composition as described above describes the effect of the present invention according to the requirements of the automaker as an example, the technical scope of the present invention is the It is not limited.

(Example)

Epoxidized soybean oil modified bifunctional epoxy and recycled waste paint powder were mixed in a ratio of 1: 1 by weight, and in order to supplement the physical properties, 5-10% by weight of a curing accelerator and a rubber polymer 10 -40 weight%, 0.5-3 weight% of surfactants or less, 5-20 weight% of plasticizers, 0.5-5 weight% of heat stabilizers, and 1-5 weight% of flow inhibitors were added.

Table 1 below shows the sealer composition prepared using the waste paint powder of the present invention, except for the main resin, the curing agent, the curing accelerator, the rubber polymer, the surfactant, the plasticizer, the coastal tablet, the flow inhibitor, and the inorganic filler were configured at the same level.

Raw material name Composition ratio (wt%) Comparative Example 1 Comparative Example 2 Example 1 Main resin Diglycidyl Ether Bisphenol A 40 0 0 Epoxidized Soybean Oil Modified Epoxy Resin 0 40 20 Recycled Waste Paint Powder 0 0 20 Rubber polymer Acrylonitrile Butadiene Rubber 6 6 2 Surfactants Sodium dodecylsulfonate 0.5 0.5 0.5 Plasticizer Dioctyl adipate 5 5 5 Heat stabilizer Beta-diketone, sterocyl benzomethane mixture One One One Flow inhibitor Fumed silica 1.5 1.5 0.5 Inorganic fillers Calcium carbonate 16 16 20 Talc 20 20 20 Carbon black 4 4 5 Hardener Dicyanamide 4 4 4 Curing accelerator Diuron 2 2 2

Specific gravity, viscosity, T-peel strength, shear adhesion, and residual adhesion rate of the structural adhesive sealer compositions of Comparative Examples 1 and 2 and Example 1 were measured according to the automotive structural adhesive sealer self-test criteria. The method of measuring peel strength, shear adhesion, and residual adhesion will be described in detail as follows.

Test strip of T-peel strength is 300mm (length) × 152mm (width) × 0.8mm (thickness) cold rolled steel sheet, degreasing one side with toluene, apply sealer at 150 ~ 200g / m3 scale, and attach joint with clip by 0.3 Secure to kg / cm2. The specimen is heat cured in a hot air dryer at 180 ± 2 ° C. for 20 minutes, and the specimen is cut into 25 mm, which is referred to as a T-peel strength test specimen.

Shear adhesion test specimens are 100 mm (length) × 25 mm (width) × 1.6 mm (thickness) on one side of a cold rolled steel sheet with a sealer applied on a scale of 150 to 200 g / m3, with a single overlapping specimen with an adhesive area of 3.125 cm2. After manufacturing, fix the joint with a clip and heat it for 180 ± 2 ℃ for 20 minutes. The heat-hardened test pieces were measured at 20 ± 2 ° C. for 2 hours, and then measured shear adhesion strength and residual adhesion rate. The results are shown in Table 2.

Test Items Reference value Comparative Example 1 Comparative Example 2 Example 1 importance 1.6 ± 0.1 1.45 1.46 1.55 Viscosity (PS) 11,000 ± 3000 9,000 11,000 13,000 T-peel strength (N / 25mm) Over 98 87 95 101 Shear Adhesion (kgf / cm2) 250 or more 245 256 260 Residual adhesion rate (%) 70 or more 40 55 82

As can be seen from the results of Table 2, when the conventional epoxy resin is used alone (Comparative Example 1), peeling strength, shear adhesion force, and residual adhesion rate show a result that does not satisfy the standard value of the automotive test standard. On the other hand, when the epoxidized soybean oil-modified epoxy resin was used as the main resin (Comparative Example 2), the shear adhesion was satisfied but the T-peel strength and the residual adhesion were insufficient. However, when the recycled waste paint powder of the present invention was added and used as a main resin (Example 1), all of the requirements were met, and the amount of expensive epoxy resin was reduced by 50% by weight.

As described above, the feature of the structural adhesive sealer composition for metal bonding using the recycled waste paint of the present invention is that the waste paint, which is a designated waste, is reactively powdered by remaining active groups using a hybrid dehydration method. It was easy to be broken by impact due to its high density, but it was possible to produce resins that gave flexibility due to the influence of urethane and modified acrylic remaining in the recycled waste paint powder, and it was used as a main resin for structural adhesive sealers for automobiles for special purposes. It was confirmed that the physical properties were equivalent to or greater than the physical properties. Therefore, as a way to increase the waste paint recycling rate while reducing the use of expensive epoxy resin, it is possible to commercialize a variety of products as an alternative functional material of the epoxy resin.

Claims (2)

100% by weight of regenerated waste paint containing active groups as main resin, 10 to 40% by weight of acrylonitrile butadiene rubber as rubber, and sodium dodecylsulfonate as surfactant compared to epoxidized soybean oil modified epoxy (15% by weight of epoxyized soybean oil) 0.5 to 3% by weight, 5 to 20% by weight of dioctyl adipate as a plasticizer, 50 to 100% by weight of calcium carbonate and talc mixture as an inorganic filler, 5 to 10% by weight of dicyandiamide as a curing agent, 5 to Diuron as a curing accelerator 10% by weight, 0.5-5% by weight of beta-diketone and stearoylbenzomethane mixture as heat stabilizer, 1-5% by weight fumed silica as flow inhibitor The structural adhesive sealer according to claim 1, wherein the mixing ratio of the waste paint powder (particle diameter: 5 to 50 µm, water content: 5% or less) prepared by epoxy resin and physicochemical dehydration is 1: 1 by weight. Resin composition

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