HU231193B1 - Thermosetting hybrid resin and application thereof as a heat shield for protection of the base plate of motor vehicles - Google Patents

Description

The present invention relates to a thermosetting hybrid coating system formed of epoxy resin and unsaturated polyester resin, to its use as a heat shielding coating for automobile bottom plates, and to a method of applying the same. The coating system of the present invention is a composition for making a crosslinked composite thick coating that is resistant to mechanical, corrosion and high temperature influences.

A high-fill liquid, thick-coating, two-component, hybrid coating system consisting of a thermosetting two-component thermosetting and an unsaturated polyester resin, comprising one component of the coating system, component A ¹ , a liquid epoxy resin, a polyester resin initiator and a component B as a component, it contains a liquid unsaturated polyester resin, a liquid epoxy resin crosslinker and two-component additives, as well as Al (OH) ₃ , hollow glass beads and cork powder in addition to the usual fillers. The invention further relates to the use of a thermosetting two-component hybrid coating system of epoxy resin and unsaturated polyester resin as a heat protective coating for the bottom plate of motor vehicles.

Thermosetting hybrid resin coating system and its application as a heat shield coating for the protection of automobile bottom plates

The present invention relates to a thermosetting hybrid coating system made of epoxy resin and unsaturated polyester resin, to its use as a heat protective coating for the bottom plate of motor vehicles, and to a method of applying the same. The coating system of the present invention is a crosslinked composite thick coating composition that is resistant to mechanical, corrosion and high temperature effects.

The steel base plates of motor vehicles are subject not only to corrosion, mechanical damage due to chipping, but also to a strong heat effect above the exhaust system, which can even cause a fire hazard,

To protect against corrosion, the steel surface is usually coated with a corrosion inhibitor. It can be paint, resin.

The bodywork of motor vehicles is generally coated with a chassis protection coating, which has a predominantly corrosion protection function.

In addition to these main tasks, chassis protective coatings also have a sound-absorbing effect. The relatively thick layers of chassis protection are usually applied to the surface wet, i.e. they are liquid or paste-like masses which are hardened after application to the chassis of a motor vehicle body. Here, it is preferred to use thermosetting chassis protective coating compositions which are gelled in an oven after application. Commonly used compositions are plastics mixed with plasticizers and builders, such as PVC or (meth) acrylates.

The chassis of motor vehicles is exposed not only to winter salting, but also to the abrasive and corrosion-promoting effects of rock fragments and gravel erupting from the road. Cavities that are not subject to strong abrasion are sprayed with coatings containing waxes and protected from corrosion caused by moisture. The parts of the chassis that are more exposed to corrosion and abrasion are usually coated with a thick coating based on bitumen, paraffins or thermoplastics (eg PVC, ABS, etc.). However, there are

-2 parts of the chassis where not only the above corrosive or promotional effects occur, but also the coating must withstand heat, Such parts of the chassis, such as parts close to the exhaust system, In these places coatings containing bitumen or paraffins they may soften and wear off the surface to be protected more easily and after a while do not perform their corrosion protection function with sufficient effectiveness. At these locations, the heat protection of the coated chassis or bottom plate is provided by heat shielding metal plates mounted between the exhaust system and the bottom plate. Such solutions are described in Audi Ag, (DE): DE19836970, Daimler Ag. (DE). DE102012013876 A1 (Motor vehicle eg, passenger car has lining portion in intrusion case that is slid at heat shield and avoids collision with respect to exhaust system, and heat shield which is provided between exhaust portion and lining portion).

This solution requires time-consuming extra work during the assembly of the car, which involves welding and assembly. However, this sheet steel heat shield is more exposed to corrosion due to the combined presence of winter salt scattering and relatively higher temperatures,

In order to overcome the assembly disadvantages described above, it is necessary to design thick-coating compositions which have a very good heat resistance and protect the surface of the car chassis from overheating for a long time in areas exposed to high heat, as well as corrosion and cracking. , can also be applied with so-called “fiat stream technology.

In addition to the high filler thick coatings mentioned above, thick coatings based on epoxy resin and unsaturated polyester resin are also widely used in the industry for corrosion protection of steel surfaces. The advantageous properties of these coatings are known, but they are not generally used in the protection of motor vehicle chassis. Both epoxy resin and polyester have different advantageous properties. Thus, unsaturated polyester resins can be easily handled during use with relatively good mechanical properties. Epoxy resin systems have excellent mechanical and thermal properties and are very good

-3 their water resistance and low shrinkage during curing. Their heat resistance can reach 140 ° C when wet and 220 ° C when dry, but the coating is sensitive to the exact ratio of epoxy resin to crosslinker measurement.

Due to the different crosslinking properties during use, the crosslinking and curing times of the two systems can be set differently. In the unsaturated polyester resin, the crosslinking system is formed by polymerization of the unsaturated bonds. The amounts of accelerator and initiator control the crosslinking. In the case of epoxy resins, the epoxy groups react with the active groups (e.g., amine groups, anhydrides) of the multifunctional crosslinker, so that the crosslinking reaction is very sensitive to maintaining stoichiometric ratios.

The thickly applied chassis protective layer has a minimum thickness of 200 μm on at least 30% of the application surface. It is particularly advantageous to apply a layer with a thickness of at least 200 [mu] m, but most preferably 350-2000 [mu] m, over at least 80% of the application area of this coating.

Conventional wet coatings can be used as chassis protection. They are primarily based on PVC or acrylic, which are adjusted to a paste by the addition of plasticizers. Above all, coatings are used which are hardened (gelled) by the addition of heat.

Examples of various thick coatings are JPH 1129133 (A) from Nippon (HIGHSTRENGTH POLYURETHANE HEAVY-DUTY CORROSIONPROOF COATED STEEL MATERIAL); JPH 1158609 (A) (HEAVY-DUTY CORROSION-INHIBITIVE STEEL MATERIAL COATED WITH POLYESTER) and epoxy resin coating in JPS 87158267 (A) (PREVENTION OF STRESS CORROSION CRACKING OF STEEL PRODUCT). According to the solution described in JPH 1129133 (A), a layer of polyurethane having a thickness of 1 to 6 mm is applied to the steel surface provided with the printer, on which a layer of polyester containing glass fiber is also laminated. JPH 1158609 (A) uses a 1-10 mm thick polyester layer containing glass fibers as a high-strength thick coating for corrosion protection. JPS 87158267 (A) for the protection of high-strength steel sheets against stress corrosion by corrosion-resistant pigments and coupling agents based on chromate, molybdate and phosphate.

An epoxy or polyurethane-based primary coating is coated with a thick epoxy resin coating.

It is an object of the present invention to provide a thick resin-coated composition suitable for resisting heat from an exhaust system when applied to the surface of an automotive corrosion protection sheet or not already coated and to protect the coated or uncoated surfaces from overheating and increase their corrosion. with this longevity. We also aimed to combine as many of the advantageous properties of the previous coating systems as possible. It is also a requirement for the preparation of the composition according to our object that it can be applied by the fiat stream process, which is widely used in the automotive industry for the application of thick coatings.

It is a finding of the present invention that the advantageous properties of epoxy resin and unsaturated polyester resin coatings can be combined to form a coating composition from two different types of resin systems. It is known that epoxy resin compositions generally consist of two components, namely an epoxy resin moiety (component 'A') and a crosslinking moiety (component 'B') selected from two or more functional compounds that react with the epoxy group. Polyester resin compositions, on the other hand, can be crosslinked with an initiator and an accelerator or an accelerator. In many cases, the polyester compositions are prepared by mixing the initiator with the carrier (which may also be a filler that is otherwise part of the composition) during use with the polyester resin, apparently as a second, i.e., 'B' component. This makes it easier to set the mixing ratio.

By combining the two systems into a two-component composition, the advantages of both thermosetting resin systems can be exploited to protect steel sheets from heat and corrosion. Of course, such systems may be useful in other applications.

The resin system of the present invention consists of two components, component A and component B. Both components are liquids containing fillers and other additives and, when mixed together, irreversibly harden and crosslink. After curing on a solid surface, resin mixture “A” and “B” are removed from the solid surface

-5 can only be removed by destruction.

The two main components of the resin system of the present invention are epoxy resin and unsaturated polyester resin. Known crosslinkers are used to crosslink the epoxy resin, preferably selected from the group consisting of metaphenylenediamine, methylhexahydrophthalic anhydride (MHHPA), phthalic anhydride, maleic anhydride and bis (4-aminophenyl) methane. Peroxides are generally used as initiators for initiating the crosslinking of the polyester, preferably one of lauroyl peroxide, acetylbenzoyl peroxide, benzoyl peroxide, 2-butanone peroxide, methyl ethyl ketone peroxide and methyl isobutyl peroxide.

1-21% aluminum flakes, 1-31% cork powder (particle size: 0.2-1.5 mm), 30t% aluminum hydroxide (particle size: 0.02 mm), A -10t% hollow glass sphere was used with a 'Q-cell' (particle size: 0.02-0.07 mm) and 1-31% ground glass fiber (fiber length: 0.5-1.0 mm).

The system according to the invention is designed to contain epoxy resin in one of the components (component A) and one of the peroxides initiating the crosslinking of the unsaturated polyester resin in addition to the other additives to be used. The other component (component 8) contains the unsaturated polyester resin and the crosslinker of the epoxy resin, among other additives.

Experiments were performed to assemble the epoxy-polyester resin hybrid system and it was found that the unsaturated polyester-based component can be used in the system only if the mixture material behaves unchanged after mixing, so it does not increase in viscosity, does not react with other component. Our experiments have shown that unsaturated polyester fits best in the system when anhydride-type crosslinkers are preferably used as the crosslinker of the epoxy resin, i.e., this type of crosslinker is mixed with the unsaturated polyester in component B. Crosslinkers of this type did not react with the unsaturated polyester resin.

The peroxide-type initiator can also be incorporated into the Ά 'component without reacting with the epoxy resin at room temperature. This component can also be stored for several months without any noticeable change in properties.

After mixing the -6Αζ Ά 'and' B 'components at room temperature, the reaction does not start immediately because the peroxide (benzoyl peroxide) used in the present invention decomposes only very slowly at room temperature and therefore does not initiate the polymerization / crosslinking of the polyester component. However, it is known that not only high temperature but also ultraviolet light can initiate the decomposition of peroxide, which results in the release of free radicals and this causes the polymerization of the polyester. It follows that after mixing and applying the mixed Ά 'and' B 'components, but before heat treatment, the use of UV light, if necessary, accelerates the decomposition of the initiator, thereby stabilizing the coating and significantly reducing or preventing its flow during heat treatment.

The resin hybrid system of the present invention is illustrated by way of example. However, it should be noted that one skilled in the art can routinely experiment with many other applications using the inventive concept without altering it. The examples given are merely illustrative of the invention without limiting it to the invention to which it relates.

Examples of heat-insulating, corrosion-resistant hybrid resin coating systems:

Resin raw materials used:

Bisphenol A diglycidyl ether epoxy resin:

- Ipox ER 1010: epoxy equivalent: 186-192 g / eq; viscosity: 10000 -14000 mPa.s (25 ° C) manufacturer: Ipox Chemicals Kft, HU

Epoxy resin crosslinking methylhexahydrophthalic anhydride (MHHPA): viscosity 50 - 70 mPa.s (25 ° C) Unsaturated polyester resin based on isophthalic acid:

- Crystic 199: clay equivalent: 27 mg KOH / g; viscosity 600 mPa.s (25 ° C)

- manufactured by Scott Bader, UK

Example 1, Component A: (215.6 tr)

epoxy resin Ipox ER 1010 100 tr benzoyl peroxide 50% by weight powder aluminum flakes 0.6 tr 5tr AI (0H) 3 (20 μm particle size) 100 tr cork powder (1 mm particle size) 10 tr

"Component 8: (280 tr)

polyester resin Crystic 199 50 tr MHHPA 80 tr

hollow glass bead (Q-cell, 20 μm particle size) 40 tr

Al (OHh (20 pm particle size) 100 tr cork powder (1 mm particle size) 10 tr

The above two components are mixed separately by one of the known mixing methods. The components are stable separately, their consistency does not change, no reaction or heat rise is observed. The use of MHHPA is also advantageous because it is a liquid with a relatively low viscosity (50-70 mPa.s, 25 ° C) and therefore facilitates the incorporation of fillers.

The two components can be stored well for a long time at room temperature without any change in their consistency. In use, components A and B are mixed thoroughly in a weight ratio of 1: 1.3. The two components can be stored at room temperature for several days until they begin to gel at 80-120 ° C for at least 5 hours.

Example 2 «Component A: (78 tr)

Ipox ER 1010 epoxy resin 30 tr benzoyl peroxide 50% by weight powder 2 tr aluminum flakes 3 tr Al (OH) s (20 μm particle size) 40 tr

-8Cork powder (1 mm particle size) „Component B: (107 tr)

Crystic 199 polyester resin

MHHPA tr tr tr hollow glass bead (CHell, 20 μm particle size) 10 tr

AI (OHh (20 μm particle size) cork powder (1 mm particle size) tr

3tr

The two components are mixed separately as described above. In use, components A and B are mixed thoroughly in a weight ratio of 1: 1.37. The mixed two components can be stored at room temperature for several days until they begin to gel at ^80-120 ° C for at least 5 hours.

The following example shows an example of a heat-insulating, corrosion-resistant hybrid resin coating system that also corresponds to the so-called “six-stream application technology” in the automotive industry.

Example 3 “Component A:

Ipox ER 1010 epoxy resin 50 tr benzoyl peroxide 50 1% powder 1.2. tr aluminum flakes 5 tr

Al (OHh (20 μm particle size) 40 tr cork powder (1 mm particle size) 5 tr „8 component:

Crystic 199 polyester resin 40 tr

MHHPA 40 tr hollow glass beads (Q-cell, 20 μm particle size) 20 tr Al (OH) 3 (20 μm particle size) 40 Irish cork powder (1 mm particle size) 5 tr

-9The two components are mixed separately as described above. In use, components "A" and "B" are thoroughly mixed in the above proportions, i.e. in a weight ratio of 1: 1.43. There is no change in room temperature for 3 hours. Above 80 ° C, benzoyl peroxide causes the polyester to crosslink and the epoxy resin to crosslink due to the congestion of the reaction heat formed.

If the crosslinking is carried out at a higher temperature, in the case of coating spraying according to the conditions of use, preferably at a temperature of about 140 ° C, the curing of the coating takes place in 10 minutes, which would be complete in hours without the accelerating effect of the polyester.

The polyester resin-free mixture of epoxy resin and MHHPA crosslinker alone had a shelf life of 12 months at room temperature and a pot life of 80 hours at 80-140 ° C (data from Broadview Technologies, Inc., USA). This also shows the accelerating effect of mixing the polyester resin system.

Application technology

The resin, which is preferably mixed in the spraying device, is sprayed with a high-pressure (5-50 x 10 ⁶ Pa) gun according to said "fiat stream technology" onto the plates or other parts on the underside of the high-passage car body to be assembled in a thickness of 1-6 millimeters. . The complete curing of the coatings on the car chassis or components is then completed in conventional furnaces and temperatures.

Preferably, after application, but before the heat treatment, the decomposition of the initiator to free radicals is accelerated by the use of UV light, thereby partially polymerizing the polyester component and thereby stabilizing the coating against any leakage during the heat treatment.

Properties of the coating with the resin hybrid coating system of Example 3:

- Density 0.65-0.85 g / cm3

- Flammability according to Ul 94 test V0

- Insoluble in water, oil and petrol

-w-

- Does not contain hazardous substances

- Measurement data for thermal insulation properties are given in Annexes I and II. table

- The heat resistance of the coating according to the invention; at least 160 X 'measured in the oven Heat resistance of the conventional coating: not more than 136 ° C measured in the oven

Table 1

Geometrical dimensions of the tested samples

1 Sample I Serial number I 1 Thickness (mmj Length (mm) Width (mm) Surface 1 2 3 4 average 1 2 £ 1 1 5.61 5.67 5.51 5.44 5.58 81.00 81.05 80.80 80.83 0.0065 4.36 4.40 4.29 4.30 4.34 80.10 80.25 80.10 80 15 0.0064 ........ | " 8.40 8.60 8.49 8.55 8.51 82.04 81.96 81.14 80.84 0.0068

Table 2

Heat conduction! temperature values measured during the determination of the factor and calculated thermal conductivity factors

Sample Maintaining Cold side Hot page Temperature Measurement Thermal conduction! serial number i meny (W) temperature temperature difference temperature factor ΓΠ rq rci fc] _ [W / mK] 1 i 5.97 51 6 04.2 12.6 57.9 0.403 _____? _____ L 5.97 ___ 51.9 62.6 10.7 57.25 0.377 3 _______ [ 5.97 50.7 67.2 16 5 58.95 0.484

Claims (9)

Patent Claims 1, Thermosetting and polyunsaturated polyester resin, two-component, high-fill liquid, thick-coating, hybrid coating system, heat-hardening two-component heat-shrinkable coating, leaving one component of the coating system, Ά 'component, liquid epoxy resin the other component, the '8' component, contains a liquid unsaturated polyester resin, a liquid epoxy resin crosslinker and two-component additives, as well as AlfOHjrOt, hollow glass beads and cork powder in addition to the usual fillers. A hybrid coating system according to claim 1, wherein the epoxy resin in component W is bisphenol A, the initiator is benzoyl peroxide and the unsaturated polyester in component '8' is unsaturated polyester in the group of epoxy resin crosslinking phthalic anhydrides. anhydride, preferably methylhexahydrophthalic anhydride. A hybrid coating system according to claim 1 or 2, wherein the coating system contains at least 601% filler. 4. Use of a thermosetting two-component high-filler liquid, thick-coating hybrid coating system consisting of an epoxy resin and an unsaturated polyester resin as a heat-protective coating for the bottom plate of a motor vehicle. unsaturated polyester resin, epoxy resin crosslinker and two-component additives, in addition to the usual fillers, Al (OHh, hollow glass beads and cork powder), and the two components are mixed and applied immediately above the exhaust part of the vehicle bottom plate, then cure the coating by heat treatment. Use of a hybrid coating system according to claim 4 as a heat shielding coating for the bottom plate of motor vehicles, which is applied by spraying onto the bottom plate. Use according to claim 4 or 5, characterized in that the coating material is sprayed onto the bottom plate by "fiat stream" technology. 7. Figures 4-6. Use according to any one of claims 1 to 4, characterized in that the coating material is exposed to UV light for at least 10 seconds after spraying before heat treatment. 8. Figures 4-7. Use according to any one of claims 1 to 4, characterized in that the coating system contains at least 601% filler. 9. Figures 4-8. Use according to any one of claims 1 to 4, characterized in that the coating material is applied to the bottom plate in a thickness of 2 to 9 mm.