JPS6157351B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a wax-based aqueous emulsion composition that is applied to protect the painted or metal surfaces of automobiles, agricultural construction machinery, and other machinery and equipment during transportation and storage.
The main component is a hydrophilic wax with a relatively low melting point so that it can be easily removed once the intended protection period is completed, and defects resulting from its use, such as heat resistance and water resistance during the protection period, are avoided. In order to compensate for deficiencies and improve the gloss and appearance of the coating film, a small amount of a wax-like substance produced by copolymerizing an olefin with 24 or more carbon atoms and maleic anhydride is added, and if necessary, This invention relates to a composition in which other ingredients are added and dispersed and emulsified in water. In recent years, the need for temporary protective coatings has been gradually recognized in order to protect products such as automobiles in good condition until they reach the final consumer, and various coating agents have been developed for this purpose. has been done. The following items can be considered as properties and functions required for this type of coating agent. (1) The components of the composition used are inert to the surface of the product to be protected; (2) they form a good protective film; and (3) they are protected against air, rain, humidity, light, and external forces during the protection period. (4) It must protect the surface of the product from dust, heat, cold, etc., and the protective film itself must not be subject to deterioration. (4) It must be easy to remove when the protection period is over. Painting agents developed for this purpose include:
So far, we have developed wax oils (wax dispersed in a solvent, e.g., Tokko Sho 49-5212), strippable films (forms a continuous film after application, and can be peeled off when no longer needed, e.g. Tokko Sho 49-5212). 44-3098), aqueous emulsion (wax emulsified and dispersed in water, e.g. Japanese Patent Publication No. 45-34030)
Among them, the aqueous emulsion type has many advantages in terms of safety, pollution prevention, and economics because it does not use a solvent. However, this type of temporary surface protection agent usually requires contradictory properties: a strong protective film during use and easy removal when no longer needed. The emulsion is made by combining easily compatible ingredients, and the protective film formed by painting this emulsion is said to be impervious to rainwater and moisture.
This also requires contradictory properties, so
It is difficult to formulate a formulation that is satisfactory in all aspects, and to date no aqueous emulsion for surface protection that can be used in a wide range of practical applications has emerged. The present inventors have studied various aqueous emulsions containing wax as a main component with the aim of producing aqueous emulsion-type surface protection compositions, and have found the following. Of the four requirements listed above, it is relatively easy to produce an emulsion that satisfies (1) to (3), but it is difficult to simultaneously satisfy (4). In other words, it is easy to emulsify a suitable wax or other ingredients and apply it to form a strong protective film, but almost all of the protective films formed in this way can be formed by relatively simple means such as steam injection after a certain period of time. It cannot be removed. In view of this situation, in developing a coating agent that satisfies all of the conditions (1) to (4) above, the present inventors first considered good removability as the first condition, and found that We have found that this condition can be met by using a melting point wax as the main component and an emulsifier with relatively high hydrophilicity. For this reason, we adopted a special wax as described below as the main ingredient,
Generally, a protective film with good removability can be created by using a combination of a low melting point wax such as paraffin or beeswax and a suitable emulsifier as the main ingredient. However, the coating formed in this way has insufficient hardness, heat resistance, and water resistance, so to compensate for these aspects, other suitable waxes are added as subcomponents. It is necessary that the added wax compensate for the defects in the coating consisting of the main component, and at the same time, the addition should not impair the good removability of the main component. Ceresin, Hoechst Wax OP, R-21, etc. were found to be suitable to some extent as waxes that meet these conditions, but further studies revealed that alpha-olefins with a carbon content of ₃₀ or higher and maleic anhydride were mainly used. It has been found that a wax-like substance produced by copolymerization (hereinafter referred to as copolymer wax) is particularly suitable as a subcomponent that satisfies this purpose. An example of the copolymerized wax studied is that it has a touch point of 75°C and a penetration level of 4, and is neither particularly high in melting point nor particularly hard compared to other waxes.
Due to its high melt viscosity (approximately 500 ^cp at 100°C), it improves the heat resistance (presence or absence of dripping at 80°C) of the film, which is mainly composed of a low-melting wax, and increases the hardness and water resistance of the film. The resulting coating becomes glossy, smooth, and translucent, and there is a noticeable difference in appearance from the coating without this addition and the white opaque coating produced when Ceresin, Hoechstwax, or the like is added. Although the copolymer wax itself is capable of good emulsification, a film formed by itself has poor removability, so it can only be used as a subcomponent. The emulsion formulation intended for protective coatings can be varied over a wide range, but generally the main component, low melting point wax (mp 50-75°C), needs to be added to It is necessary to contain at least 25 parts by weight to enable good emulsification.
Furthermore, a copolymer of α-olefin of mainly _C24 or higher, preferably mainly _C30 or higher, and maleic anhydride, which is added as a subcomponent, is added to the main component in order to improve the heat resistance of the low melting point wax, which is the main component. On the other hand, if it is added in an amount of 15 wt% or more, a remarkable effect will be obtained, whereas if it is added in an amount of more than 40 wt%, the removability will be markedly reduced, causing problems. Therefore, the composition of the present invention mainly contains 5 to 25 parts by weight of a low melting point wax (mp50 to 75°C).
The basic component is a mixture of 0.75 to 10 parts by weight (15 to 40 wt% based on the low melting point wax) of a copolymer of C ₂₄ or higher, preferably C ₃₀ or higher α-olefin and maleic anhydride. In addition, when preparing an aqueous emulsion, add 1 to 5 parts by weight of a mixture of one or more emulsifiers selected from nonionic, anionic, or cationic emulsifiers, and various compounding agents as necessary, It is preferable to add water to make the total amount 100 parts by weight. The low-melting point wax used as the main ingredient is a special oxygen-containing wax made by the method described below, and has extremely good emulsifying properties, forming a smooth film and preventing it from corroding the painted or metal surfaces of products that should be protected. It can be easily removed by steam injection. The manufacturing method for this special low melting point wax is 135〓~145〓paraffin 10~
80 parts by weight and 90 to 20 parts by weight of a wax-like ethylene polymer mainly in the range of C ₂₄ to C ₆₀ , and 3 to 25 parts by weight of maleic anhydride to 100 parts by weight of this mixed wax; It is obtained by reacting 0.5 to 5 parts by weight of an organic peroxide at 120°C to 220°C for 0.5 to 6 hours, and removing volatile substances by vacuum distillation. The wax thus obtained is a mixture of maleated paraffin, maleated ethylene polymer, unreacted paraffin, ethylene polymer, and other components, and has a melting point of 65°C to 75°C. Although it has a low penetration rate, it has a hard penetration of 1 to 4 and can be emulsified extremely easily. Suitable emulsifiers include nonionic emulsifiers such as alkyl phenyl ethylene oxide ether type, oleyl or stearyl ethylene oxide ether type, anionic emulsifiers such as potassium oleate, cationic emulsifiers such as morpholine triethanolamine, or combinations thereof. , the total amount of emulsifier is 5 to 25 parts by weight per 100 parts by weight of wax. In addition to adding a copolymer wax to improve the heat resistance, water resistance, gloss, and other appearance of the film, other ingredients are emulsified in water as necessary, such as phenolic resin to improve the adhesion of the film. . Emulsification is easy and no special techniques are required. After applying the obtained emulsion to the surface of the product to be protected by spraying or brushing, dry naturally for 2 to 6 hours or heat dry (infrared irradiation, hot air blowing, leaving in a heating oven, etc.)
The coating is completed in 5 minutes to 2 hours. This coating showed no change in quality after 250 hours of accelerated weathering test (63℃ arc lamp irradiation, water sprinkling every 2 hours for 18 minutes), heat resistance test at 80℃ for 96 hours, and water resistance test at 40℃ and immersion in water for 240 hours. No change was observed on the surface of the product after this film was removed. After the accelerated weathering test, water vapor is sprayed for 10 seconds from a nozzle of a certain design on the film, and the film is removed in an approximately circular shape of 15 to 25 mm diameter, leaving the product surface in perfect condition. As described above, the aqueous emulsion for surface protection with good removability of the present invention is completed by adding a copolymerized wax of mainly C24 _or higher, preferably mainly C30 _or higher, α-olefin and maleic anhydride. will be specifically explained below using examples,
It goes without saying that the present invention is not limited to the scope of the embodiments, and the scope of the present invention is not limited by the embodiments. Example of manufacturing low melting point wax: 500g of 145°F paraffin and mainly _C28 to _C50
(average carbon number C ₃₃ ) (white color, penetration rate 11, melting point 80℃, number of double bonds 32/
1000C, of which 78% is vinyl type and 18% is vinylidene type.
%, ) was placed in two four-necked flasks, and 130 g of maleic anhydride was added thereto. Pass through the water-cooled condenser to open the inside to the atmosphere.
The atmosphere was replaced with _N2 , and the temperature was raised to 150°C in an oil bath. On the other hand, ditertiary butyl peroxide (DTBP) 10
Dissolve g in 50 c.c. of xylene and put it into the dropping funnel.
The mixture was added dropwise over 30 minutes with thorough stirring. Since the reaction was accompanied by heat generation, the reaction temperature was maintained at 150°C by controlling the dropwise addition rate and removing the oil bath. After stirring for an additional 30 minutes, the pressure was reduced to 5 mmHg at the same temperature, and volatile substances were completely distilled off over 2 hours while blowing in a small amount of _N2 . The wax obtained in this way had a saponification value of 90, a penetration value of 1, a light yellow color (Gardner value of 3), and a melting point of 70°C.As it was a little cloudy in its molten state, it was coated with paper with a pore size of approximately 3μ. A clear wax was obtained by applying pressure. This wax will be temporarily referred to as wax A. Comparative Example 1 (Aqueous emulsion formulation) Wax A 15g Emulgen 930 (trade name) (manufactured by Kao Atlas Co., Ltd.,
polyoxyethylene nonyl phenyl ether)
1.2g Potassium oleate 1.05g Sumilite PR19788 (Product name) (Sumitomo Duretsu
Co., Ltd., Phenol Resin) 1g Water 81.75g All components except water and potassium oleate were placed in a 200cc beaker and heated and melted at 110°C. On the other hand, the entire amount of potassium oleate was added to water, heated to a boiling state, and gradually added to the aforementioned mixture of wax and the like while stirring. After the addition was completed, the mixture was slowly cooled to room temperature while stirring was continued. The resulting emulsion was a homogeneous white emulsion with a slight bluish tinge, and had a viscosity of 10 ^cp at room temperature.
This emulsion was allowed to stand at room temperature for 3 months without any change in quality. (Coating) The test piece was a 150 mm x 70 mm (1 mm thick) mild steel plate coated with black aminoalkyd resin, and the emulsion was sprayed from a nozzle and dried by irradiating it with an infrared light for 5 minutes. The average thickness of the wax film was 15 μm when calculated from the weight. (Test) The following items were tested on the above test piece. The results are shown in Table 1. (1) Appearance and feel of wax film (2) Heat resistance test Stand vertically in a thermostat at 80℃ for 96 hours.
Dripping, cracking, and other changes in the wax film were observed. Furthermore, the wax film was heated and melted with an infrared light and wiped off with gauze, and the alkyd painted surface was observed for gloss, blistering, and other changes. The results are displayed in three stages: no change (○), slight change (△), and some change (x). (3) Water resistance test Immersed in pure water kept at 40℃ for 240 hours and observed the wax coating and changes in the painted surface after the wax coating was removed. (4) Accelerated Weather Resistance Test The wax film and the painted surface after the film was removed were tested for 250 hours at 63°C with cold water falling for 18 minutes every 2 hours in a sunshine weather meter manufactured by Toyo Rika Kogyo Co., Ltd. We observed changes in (5) Removal test Through a nozzle with a hole diameter of approximately 3 mm, spray 1 Kg/cm ² G water vapor for 10 seconds from a position approximately 50 mm away.
The diameter of the circular trace where the wax coating was removed was measured. This test targeted the coating after the accelerated weathering test in section (4). The results are shown in Table 1, with traces removed having a diameter of 15 mm or more as ○, less than 15 mm to 8 mm as △, and less than 8 mm as ×. Comparative Example 2 In place of 15 g of Wax A in Comparative Example 1, 12 g of Wax A and 3 g of Hoechst Wax OP were used, and the other conditions were the same as in Comparative Example 1. Comparative Example 3 Instead of 15g of wax A in Comparative Example 1,
Wax A 12g and Hoechst Wax R-21 3g
was used, and everything else was the same as in Comparative Example 1. Comparative Example 4 In place of 15 g of Wax A in Comparative Example 1, 12 g of Wax A and 3 g of Ceresin were used, and everything else was the same as in Comparative Example 1. Example 1 Instead of 15 g of wax A in Comparative Example 1, wax
A12g and Diakaruna 30 (manufactured by Mitsubishi Kasei Corporation, mainly
3 g of a copolymer wax of C ₃₀ or higher α-olefin and maleic anhydride was used, and the other conditions were exactly the same as in Comparative Example 1. Comparative Example 5 Instead of Wax A in Comparative Example 1, Diakaruna was used.
30 15g was added, and the other procedures were exactly the same. The produced emulsion was a white emulsion with no blue tinge, and seemed to have a slightly coarser particle dispersion than that of Comparative Example 1. Examples 2 and 3

[Table] Based on the above recipe, the same procedure as Comparative Example 1 was carried out. Example 4 The wax emulsion obtained in Comparative Example 1 and Examples 1, 2, and 3 was applied to a mild steel plate with a brush, left to dry, and the wax coating was removed after one week. No change was observed on the surface of the mild steel plate.

[Table] As can be seen from the results of the Examples, Comparative Examples, and Table 1 described above, the wax coating formed from the aqueous emulsion composition according to the present invention has excellent appearance and feel;
It has excellent heat resistance, water resistance, etc., and also has excellent film removability, so it is effective as a coating agent for protecting the surface of products.

Claims (1)

[Claims] 1. (A) 135-145 paraffin 10-80 parts by weight, based on the total composition of 100 parts by weight;
90 to 20 parts by weight of a _C24 to _C60 waxy ethylene polymer are mixed, and 3 to 25 parts by weight of maleic anhydride and 0.5 to 5 parts by weight of an organic peroxide are added to 100 parts by weight of this mixed wax. (B) 0.75 to 10 parts by weight of a copolymer of C ₂₄ or higher monoolefin and maleic anhydride; 1. An aqueous emulsion composition for surface protection, characterized in that the essential component is emulsified and dispersed in water, and the content of component (B) is 15 to 40% by weight of component (A).