KR20060098147A - The process for preparing yellow lacquer from natural lacquer - Google Patents

Abstract

The present invention relates to a method for producing sulfur lacquer using natural lacquer, and more specifically, a) 65 to 95% by weight of urushiol and 5 to 35% by weight of formaldehyde extracted from natural lacquer in the presence of a basic catalyst Reacting in a mixed solution to prepare a urushiol polymer; b) 30 to 70% by weight of the urushiol polymer prepared in step a) and acrylate monomer having at least one acryl group and 70 to 30% by weight of acrylate oligomer in an organic solvent in the presence of an acid catalyst selected from organic or inorganic acids. Reacting is characterized in that the step of producing a lacquer lacquer.

The yellow lacquer prepared in the present invention is a transparent yellow liquid, which does not cause allergies like lacquer, and when it is applied to a soft, metallic white or yellow metal, it expresses a soft and brilliant golden luster, and when applied to wood, it is transparent to preserve the texture of wood. As a result, it is possible to reduce the pollution and the complicated process caused by gold plating as well as to substitute the import of gold, thereby developing jewelry and high-quality products.

Lacquer, yellow lacquer, yellow lacquer, formaldehyde, paint, natural paint

Description

Process for preparing yellow lacquer using lacquer {The process for preparing yellow lacquer from natural lacquer}

1 is an FT-IR spectrum of a reaction product of urushiol and Methyl acrylate,

2 is a ¹ H NMR spectrum after the reaction of Chinese urushiol and Methyl acrylate,

Figure 3 is a skin allergy test results of sulfur lacquer raw material and sulfur lacquer.

The present invention relates to a method for producing sulfur lacquer using natural lacquer.

Among the natural lacquer produced in Korea are lacquer and yellow lacquer. Hwangchil is a lacquer, like lacquer, which is grown on the southwestern coast of the Korean peninsula or on the archipelago of islands. It is yellowish in the air. Refine it and apply it to the metal to give it a brilliant and soft golden color. Hwang-chil's characteristic is that he has gone through the process of historical controversy that paid all tribute to China. Hwangchil, a natural product capable of expressing a golden color, has a problem in that the production volume is very limited and the price is high, and it is limited to jewelry, and there is a weakness in water because of trust.

Lacquer is heat resistant, antibacterial, and hygroscopic, and has excellent characteristics of coating, and despite being a natural lacquer that has been used traditionally and preciously, it is allergic to it and has a black color because it can not be handled by anyone. The drying of the coating film has a disadvantage that it must be dried for a long time by maintaining the appropriate temperature and humidity in the dark. In addition, lacquer and yellow lacquer are collected from nature, making it difficult to supply large quantities.

Kashchil is a chill used in the industrial field. Kash oil is condensed with formalin or paraformaldehyde under a base catalyst to make a brown or black cashew paint with a certain molecular weight.

However, in this case, it is difficult to control the polymerization degree and molecular weight uniformly in the synthesis of resin due to some compounds and impurities generated in the extraction process included in the cashew oil itself, and the physical properties are not uniform. The gloss and image sharpness of the coating film are poor, and the water resistance and the solvent resistance are limited, so the weather resistance is also poor.

On the other hand, Korean Laid-Open Patent Publication No. 2003-0078237 discloses a lacquer using a silicone-based ultraviolet curing agent and a photoinitiator from lacquer, but there is a problem of not only using an expensive photocuring agent but also inferior durability and glossiness. No. 95-11893 discloses resins obtained by condensation of paraformaldehyde on lacquer, followed by modification of condensates of phenols and polybasic acids with oils and fatty acids, but the modified resins are subjected to heat by esterification. The curing time is hardened by causing a condensation polymerization reaction, and the curing time is later than the radical reaction by photocuring, and when the coating film is thick, when the water generated inside the coating film cannot escape due to surface curing, the coating film becomes unstable and the performance of the coating film is deteriorated. And the disadvantage that reverse reaction occurs and aging easily occurs. ought.

An object of the present invention is to produce a yellow lacquer similar to the yellow lacquer using a natural lacquer, while utilizing the unique properties of the yellow lacquer, the production cost is low, does not cause skin allergies, and the manufacturing method of the yellow lacquer excellent in the physicochemical properties of the coating film To provide.

Another purpose is to provide a yellow lacquer coating that is transparent when painting on timber, which preserves the texture of the wood as it is, and can reduce the pollution and complicated processes caused by gold plating as well as the substitution effect of gold import. .

The present invention relates to a method for producing sulfur lacquer using natural lacquer, and more specifically, a) 65 to 95% by weight of urushiol and 5 to 35% by weight of formaldehyde extracted from natural lacquer in the presence of a basic catalyst Reacting in a mixed solvent to prepare a urushiol polymer; b) 30 to 70% by weight of the urushiol polymer prepared in step a) and acrylate monomer having at least one acryl group and 70 to 30% by weight of acrylate oligomer in an organic solvent in the presence of an acid catalyst selected from organic or inorganic acids. Reacting to produce a lacquer; In addition, the sulfur lacquer and the photoinitiator prepared by the method for producing a sulfur lacquer according to the present invention is dissolved in a polar organic solvent and applied to a member for forming a coating film by photocuring or heat curing to form a lacquer coating It is characterized by.

Hereinafter, the present invention will be described in detail.

The method for producing sulfur lacquer using the natural lacquer according to the present invention includes the following steps.

a) preparing a urushiol polymer by reacting 65 to 95% by weight of urushiol and 5 to 35% by weight of formaldehyde extracted from a natural lacquer solution in a mixed solution of water and a polar solvent in the presence of a basic catalyst.

b) 30 to 70% by weight of the urushiol polymer prepared in step a) and acrylate monomer having at least one acryl group and 70 to 30% by weight of acrylate oligomer in an organic solvent in the presence of an acid catalyst selected from organic or inorganic acids. Reacting to produce a lacquer.

Urushiol, a component of lacquer, has a slight molecular structure difference in each region, and urushiol has a hydroxyl group at carbon positions 1 and 2 of the benzene ring and an unsaturated aliphatic chain having 15 carbon atoms at position 3 . Raw spring lacquer has less unsaturation and lower urushiol content than Chinese lacquer, but it is not unusable.

In the present invention, the urushiol as a main component is extracted and purified from the lacquer collected from nature, and the lacquer tablet is a component that is not dissolved in acetone and urushiol dissolved in acetone when acetone is added to raw lacquer (hereinafter referred to as 'acetone powder'). ), And the method of separating urushiol from acetone powder includes centrifugation, filtration, and a method of taking a supernatant after standing for a long time. In the present invention, any of the above methods may be used. However, the centrifugal separation method requires a lot of equipment costs, and the filtration method has a disadvantage in that filtration is not easy because the acetone powder is fine during filtration, so that it is not easy to filter, but it is left standing by mixing with the solvent and taking a supernatant to evaporate the solvent. It is natural but very easy to work with and is the most preferred method of purification.

In the present invention, the stationary method was adopted. Specifically, the natural lacquer was dissolved in acetone in a volume of 2 to 5 by volume, the material which was not dissolved in acetone was settled, and then only the supernatant was taken to evaporate acetone in a reduced pressure evaporator to obtain pure urushiol. . Urushiol may be slightly different depending on the place of origin, but is extracted about 55 to 65% by weight relative to the natural lacquer.

The acetone powder layer which is insoluble in acetone, the solvent used in the separation of urushiol, is laccase and glycoproteins.The solution layer is combined with the urushiol layer by filtration or centrifugation in a centrifuge, and the precipitate is stored in a refrigerator and mixed with lacquer. Can also be used.

The extracted urushiol is mixed in a mixed solvent of formaldehyde, water, and a polar solvent, followed by condensation polymerization by adding a basic catalyst to prepare a urushiol polymer.

The amount of formaldehyde may vary depending on the purpose used, but it is preferable to use 5 to 35% by weight. In this case, when used at 5% by weight or less, the degree of polymerization is lowered and the curing rate is increased. If the content is 35% by weight or more, unreacted formaldehyde is present after completion of the reaction, which is inefficient. Formaldehyde is preferably used formalin which is 37% aqueous formaldehyde solution. Paraformaldehyde may also be used, but the reaction rate is slower than that of using formalin, and the reaction efficiency is not good. This may be due to the slower decomposition rate of paraformaldehyde than that of formaldehyde and urushiol. In terms of price, formalin is also economical.

Any basic one may be employed as the basic catalyst used in the preparation of the urushiol polymer, but it is preferable to use one selected from ammonia water, triethylamine, triethanolamine, dimethanolamine, or a mixture thereof, compared to urushiol. Preference is given to using 0.1 to 10% by weight.

If a solvent is not used, there is a problem that the reaction does not proceed uniformly, and it is used as a mixed solvent of water and a polar solvent, and the polar solvent used as the mixed solvent is preferably a lower alcohol such as ethanol or propanol. 400 to 1000 ml per mole of urushiol is preferable, and water used as the mixed solvent may use water contained in formalin. The reaction is preferably carried out at reflux temperature of the mixed solvent at atmospheric pressure for 1 to 5 hours, but if necessary, the reaction can be carried out at the reflux temperature or more, in this case it is allowed to react within the range of 150 ℃ or less at atmospheric pressure conditions It is preferable.

At the beginning of the reaction, the reactant is dissolved in the mixed solvent, but as the reaction proceeds, the urushiol polymer, which is a reaction product, does not melt and precipitates. When the reactor is cooled after completion of the reaction, the produced urushiol polymer is not dissolved in the solvent ethanol. There is an advantage in that the solvent and by-products can be easily removed from the reactor by being separated from the solvent and by-products. It is therefore possible to insitu the next reaction following the same reactor.

At this time, the precipitated product was washed with ethanol or the like to obtain a urushiol polymer. The solvent was concentrated under reduced pressure at 15 ° C. at 40 ° C. using a rotary evaporator to obtain a pure golden urushiol polymer. The viscosity of the pure urushiol polymer was maintained at 25 ° C. in an oven for 12 hours and measured from a BROOKFIELD LVDVE230 viscometer to range from 20,000 to 40,000 CPS.

Sulfur lacquer is prepared by reacting the urushiol polymer prepared in the above step in an organic solvent in the presence of an acid catalyst selected from an organic acid or an inorganic acid, an acrylate monomer and an acrylate oligomer. In this case, the reaction ratio of the reactant is preferably 30 to 70% by weight of the urushiol polymer, an acrylate monomer having an acrylate group, and an acrylate oligomer of 70 to 30% by weight, and the acrylic derivative is an acrylate having 1 to 6 acrylic functional groups. As monomers and acrylate oligomers, C1-C5 alkyl acrylate, C1-C5 alkyl methacrylate, melamine acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, spiran acrylate, various modified acrylic Rate and the like.

The urethane acrylate oligomer is produced by, for example, reacting a compound having two or more isocyanate groups in one molecule with an acrylate having active hydrogen. Examples of the compound having two or more isocyanate groups in one molecule include m-phenylene diisocyanate, p-phenylenedi isocyanate, toluene-2,4-diisocyanate, toluene-2,5-diisocyanate, toluene-2,6-di Isocyanate, toluene-3,5-diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'- diisocyanate-3,3'- dimethylphenyl, 4,4'- diisocyanate-3,3'- dimethyl biphenylmethane, etc. are mentioned. Moreover, as acrylate which has active hydrogen, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, glycerin diacrylate, 1, 6-bis (3-acryloxy) 2-hydroxypropyl) -hexyl ether, pentaerythritol triacrylate, tris- (2-hydroxyethyl) isocyanuric acid ester acrylate, etc. are mentioned.

The melamine acrylate is prepared by the action of the melamine compound and the acrylate having the active hydrogen, for example, the melamine compound is hexamethylolmelamine, hexamethoxymethylolmelamine, hexabutoxymethylolmelamine, monomethoxymethyl Olmelamine, monobutoxymethylpentamethylolmelamine, dimethoxymethyltetramethylolmelamine, dibutoxymethyltetramethylolmelamine, trimethoxymethylpropanemethylolmelamine, tributoxymethylpropanemethylolmelamine, tetramethoxymethyl Dimethylolmelamine, tetrabutoxymethyldimethylolmelamine, pentamethoxymethylmonomethylolmelamine, pentabutoxymethylmonomethylolmelamine and the like.

In addition, the epoxy acrylate is prepared by, for example, reacting a compound having two or more epoxy groups in one molecule and an acrylate having the active hydrogen. Examples of the compound having two or more epoxy groups in one molecule include phenol novolac. Type epoxy compound, cresol novolac type epoxy compound, cresol type epoxy compound, bisphenol A type epoxy compound, bisphenol F type epoxy compound, brominated bisphenol A type epoxy compound, brominated bisphenol F type epoxy compound, hydrogenated bisphenol A type epoxy compound, etc. Glycidyl ether epoxy compounds; Polyvalent epoxy compounds such as alicyclic epoxy compounds, glycidyl ester epoxy compounds, glycidyl amine epoxy compounds, and isocyanurate epoxy compounds; The compound etc. which have two or more epoxy groups in molecules, such as these, are mentioned.

The polyester acrylate is a compound having two or more carboxyl groups in one molecule, such as fumaric acid, phthalic acid, maleic acid, trimellitic acid, himic acid, terephthalic acid, isophthalic acid, adipic acid, sebacic acid, and the like. It can be prepared by reacting a compound with an acrylate having the active hydrogen.

 The acrylates used in the present invention used an acrylate derivative of Ebercryl series of UCB, but the acrylate monomers or oligomers are commercially produced, and thus can be easily obtained. In particular, acrylate oligomers can be divided into heat-drying acrylates and photocurable acrylates, one of them may be used, and two or more acrylates may be mixed and used according to the number of functional groups. Since the properties are different, those skilled in the art can appropriately select or modify the type of acrylate to suit the application.

In this step, at least one organic solvent is selected from n-hexane, benzene, toluene, and THF, and the amount of the solvent used is 100 to 500% by weight based on the weight of the polymer of urushiol. It is preferable to select appropriately.

As the acid catalyst, an organic acid or an inorganic acid such as p-Toluenesulfonic acid monohydrate (p-TsOH) is used.

Viscosity measurement of the obtained pure sulfur lacquer is impossible because the curing proceeds during the evaporation of the solvent after the reaction. Therefore, the practitioner can set the viscosity arbitrarily according to the kind of the solvent or the acrylic derivative used for the synthesis of the lacquered lacquer, and can set the criteria.

When the viscosity was measured as it is without separating the solvent from the yellow lacquer prepared as in Example 3, it showed a viscosity of 200 to 350 CPS (25 ° C.), and the number average molecular weight was in the range of 2100 to 2600.

In the present invention, the reaction product was analyzed by reacting methyl acrylate to confirm the reaction process between urushiol and acrylate, and the urethane acrylate oligomer having 6 functional groups was reacted with urushiol polymer to confirm the characteristic group by infrared spectroscopy. As a result, it was found that the physical properties of the polymer were improved while reacting with the double bond of the unsaturated aliphatic chain and the acrylic derivative of the urushiol polymer during the polymerization.

The present invention includes a method of forming a yellow lacquer coating by photocuring or thermosetting.

The sulfur lacquer prepared according to the present invention is dissolved in an organic solvent and applied to a member for forming a coating film to cure, thereby forming a sulfur lacquer coating film. The method of forming the coating film is drying by sunlight according to the presence and type of initiator used, It can be divided into thermosetting and photocuring. In this case, an initiator may be a conventional one of thermal initiators and photoinitiators that are commercialized and sold.

The sulfur lacquer prepared according to the production method of the present invention can be effectively cured by ultraviolet irradiation without using a photoinitiator, but it is preferable to add an initiator as long as the durability is not impaired in order to improve curability.

As the photopolymerization initiator used in the present invention, acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, xanthone, fluorenone , Benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, benzoin Propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropane- 1-one, thioxanthone, diethyl thioxanthone, 2-isopropyl thioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino -Propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,4- (2-hydroxyethoxy) phenyl- (2-hydroxy- 2-propyl) ketone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide and bis- (2,6-dimeth Oxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, ferrocene and derivatives thereof, and the like, and these photopolymerization initiators may be used alone or in combination of two or more thereof. If a deeper photocuring depth is required, titanocene-based photopolymerization initiators such as CGI784, a product of Chiba-Sveshariti Chemical, which initiates radical polymerization in the visible region, 3-substituted kmarin dyes, leuco dyes, etc. It can be used in combination as a hardening aid.

Examples of commercially available products of the photoinitiator include Irgacure 184, 369, 651, 500, 819, 907, 784, 2959, CGI1700, CGI1750, CGI1850, CG24-61, and Darocur 1116, 1173. (Made by Ciba Specialty Chemicals Co., Ltd.), Lucirin TPO, LR8893 (made by BASF), Ubecryl P36 (made by UCB), and the like.

In the case of coating film formation by thermal curing of sulfur lacquer according to the present invention, curing is possible by applying heat, but a heat-polymerization initiator may be optionally added. Thermal polymerization initiators include peroxides, azo compounds and redox initiators that generate radicals by heat, and peroxides include benzoyl peroxide, lauroylpooxide, cumene hydroperoxide, t-butylhydroperoxide, and dicumylperoxy. Examples thereof include azo compounds such as azobisisobutyronitrile and azobis-2,4-dimethylvaleronitrile. Examples of redox initiators include hydrogen peroxide-iron (II) salt and peroxodisulfite hydrogen sulfite. Sodium, and cumenehydroperoxide-iron (II) salts.

The amount of photoinitiator or thermal initiator used in the composition of the present invention is preferably 90 to 99.99% by weight of sulfur lacquer and 0.01 to 10% by weight of polymerization initiator, in particular 93 to 99.9% by weight of lacquer and 0.1 to 7% by weight of polymerization initiator. More preferred.

The organic solvent is used to dissolve the photocurable composition and the thermosetting composition, to facilitate the coating step, and then to dry to form a film and to improve the smoothness of the coating film. Specific examples include aromatic and aliphatic hydrocarbons, alcohols such as methanol, ethanol, propanol and butanol; Ketones such as acetone, methyl ethyl ketone and cyclohexanone; Glycol ethers such as cellosolve, methyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monoethyl ether Acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and the like. These organic solvents may be used alone or in combination of two or more kinds. The amount of the organic solvent used can be adjusted and used appropriately by those skilled in the art as the degree to which the yellow lacquer according to the coating method can be adjusted to the desired viscosity.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

The hardness of the coating film in the embodiment was confirmed by the pencil hardness check method, the pencil hardness tester (PENCIL TESTER) was confirmed using Japan YOSHIMITSU, the hardness range is 6B to 9H in 17 steps. The colorimeter used TECHKON R410 and the viscometer used BROOKFIELD LVDVE230.

In order to measure the coating properties, the coated film-forming film plate used a polished SS304 stainless steel plate (5x7cm, thickness 1mm) .The UV lamp used to cure the film after spraying was 30W / cm (850V, 3.6A, 100 cm) was used to cure the coating film at 30 cm intervals from the back, and the coating film thickness after drying was 20 to 35 µm.

The thickness of the coating film was measured using a digimatic micrometer (Mitutoyo, Japan.Measurement range 0-25mm, resolution 0.001mm). Solvent resistance is the degree to which acetone does not melt when rubbed onto the coating film. The degree to which it was not entrusted or swelled when immersed in water at room temperature for 24 hours was measured. The display method was defined as good (○), medium (△) and bad (X).

Example 1

Lacquer tablets

Put 100g of lacquer in a 500ml separatory funnel, add 400ml of acetone, stop the stopper, shake well, and leave it at room temperature for 12 hours.The urushiol is separated into the dissolved upper layer and the acetone powder layer which is not dissolved in acetone. Open the stopcock at the bottom of the separatory funnel to separate the acetone powder layer and take only the supernatant and transfer it to the rotary evaporator. Rotating the flask in a rotary evaporator while evaporating the solvent acetone under atmospheric pressure to give 61g of pure urushiol.

Example 2

Preparation of yellow lacquer

Preparation of Urushiol Polymer

 A thermometer and a mechanical stirrer were attached to a 250 ml round bottom flask equipped with a reflux condenser, and 31.4 g (68% by weight) of purified urushiol and 40.6 g of formalin (37% aqueous solution) (formaldehyde standard 32) % By weight), 2.1 g of ammonia water (25% aqueous solution) and 60 ml of ethanol were added thereto, and the mixture was heated with an oil-pot and heated to 100 ° C while stirring. At this time, the solvent was refluxed, the reaction was refluxed for 3 hours 30 minutes and cooled to room temperature to separate the reaction product as an insoluble polymer in ethanol. The first reaction by-products in the liquid phase were removed and the reaction product clinging to the inner wall of the flask was added with 20 ml of pure ethanol to wash away the small amount of water remaining in the reactor and the reaction by-products. Urushiol polymer attached to the inner wall of the reactor was used for the next reaction.

At this time, the precipitated product was washed with ethanol or the like to obtain a urushiol polymer, and the solvent was concentrated under reduced pressure at 15 ° C. at 40 ° C. using a rotary evaporator to obtain a pure golden urushiol polymer. The viscosity of the pure urushiol polymer was maintained at 25 ° C. in an oven for 12 hours, measured by BROOKFIELD LVDVE230 viscometer, and was 28130 CPS. The number average molecular weight was 2099 (Mn).

Yellow lacquer synthetic

 Into a 100 ml two-neck round bottom flask equipped with a reflux condenser, 15.7 g (64 wt%) of urushiol polymer and 27 ml of benzene were stirred and 8.65 g (36 wt%) of methyl acrylate and 0.476 g of After p-TsOH (p-Toluenesulfonic acid monohydrate) was added, the mixture was heated in an oil bath and heated to 100 ° C. for reflux for 24 hours. When the urushiol was completely reacted using thin layer chromatography, the reaction was terminated. Then, 0.210 g (44% by weight of p-TsOH) sodium bicarbonate was added to neutralize the catalyst while stirring for 10 minutes. The solvent was then concentrated under reduced pressure rotary evaporator at 40 ° C. and 15 mm Hg to obtain 16.409 g of yellow lacquer.

As a result of FT-IR measurement of the prepared reactant, as shown in FIG. 1, it was confirmed that the left and right peaks were greatly reduced based on 3000 cm ⁻¹ , and particularly, cis and trans type double bonds exist the peak of the 730cm ^-1 and 990cm exhibited by the conjugated double bond of the side chain portion of the peak and urushiol around 950cm ^{-1 -1} absorption band had disappeared be seen that most by reaction with methyl acrylate, GC-MSD determined The 26.32 min peak corresponding to urushiol disappeared completely, and ¹ H NMR measurements showed similarities to Chinese urushiol, but 11, in 3-((8Z, 11Z) -8,11,13-pendeca trienyl) catechol 13 double bonds participated in the reaction, and the peaks appearing at 1.72, 5.44, 5.98, and 6.34 ppm were completely disappeared (FIG. 2). This means that it reacted with the double bond of the aliphatic unsaturated chain of urushiol.

Example 3

Preparation of yellow lacquer

 Urushiol polymer 15.7 g (49 wt%) and 16.05 g (51 wt%) of Ebecryl 1290 (hexafunctional aliphatic urethane acrylate oligomer) and 0.471 g of p-TsOH (p-Toluenesulfonic acid monohydrate) prepared in the same manner as in Example 2 ) Was added, and 30 ml of toluene was added thereto, and the mixture was heated with an oil bath and stirred at 115 ° C. for 7 hours while stirring.

The viscosity of the prepared sulfur lacquer was 184CPS (25 ℃), the number average molecular weight was 2220 (Mn), the viscosity measurement of the obtained pure sulfur lacquer is impossible because the curing proceeds in the evaporation of the solvent after the reaction. Therefore, the practitioner can set the viscosity arbitrarily according to the kind of the solvent or the acrylic derivative used for the synthesis of the lacquered lacquer, and can set the criteria.

Infrared spectroscopy showed that the peaks of 1635 and 808cm ^-1 , which are the double bond peaks of Ebecryl 1290, reacted with urushiol and became very small.

Example 4

Photocuring and Characterization of Yellow Lacquer

 To 3 g of sulfur lacquer prepared in Example 3 TPO (2,4,6-Trimethylbenzoyl diphenylphosphine oxide), CA173 (Chivacure 173, 2-hydroxy-2-methyl-1- phenyl-propan-1-one), CA107 (Chivacure 107, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propane-1-one), CA184 (Chivacure 184, 1-hydroxy cyclohexyl phenyl ketone) and 2 wt% After adding the weight%, 9 g of acetone was added thereto, the mixture was stirred, sprayed onto a polished stainless plate, cured with UV lamp, and examined for the characteristics of the coating film over time. Was investigated. Table 1 shows the coating film characteristics by photocuring using different types of photoinitiators, respectively, as a control with sulfur lacquer without the photoinitiator.

TABLE 1

Example 5

Thermal curing and coating film analysis of sulfur lacquer

 4 ml of acetone was added to 1 g of the yellow lacquer obtained in Example 3, and then sprayed onto a polished stainless steel plate and thermally cured in a drying oven at 80, 110, and 130 ° C., respectively. After curing, the mixture was left at room temperature for 15 days and then the characteristics of the coating film were checked. Table 2 is a result of confirming the coating properties by the thermal curing of the coating film after the curing for 22 hours at each temperature and after 15 days at room temperature after heat curing.

  TABLE 2

Example 6

Analysis of Solar Curing and Coating Properties of Sulfur Lacquer

Two samples of 3 g each of the lacquered lacquer obtained in Example 3 were added, and 5 weight% (0.15 g) of photoinitiator (TPO) was added to one of them, followed by the addition of 9 g of acetone. Sprayed the plate to cure for 5 hours under sunlight. At this time, the surface temperature was 10 ℃. After solar curing, the coating film was characterized for 1 day at room temperature, and then the properties of the coating film were examined and shown in Table 3.

TABLE 3

Comparative Example 1

UV Curing Photocuring and Coating Properties of Urushiol Polymers

After adding 5 wt% (0.15 g) of photoinitiator (TPO) to 3 g of the urushiol polymer obtained in Example 2 and adding 9 g of acetone, the mixture was well stirred and sprayed onto a polished stainless plate, followed by photocuring. Changes in hardness and chromaticity, and changes in hardness and chromaticity of the coating film after 15 days of standing at room temperature were investigated. Table 4 shows the photocuring and characterization of the sulfur lacquer raw material added 5% by weight of the photoinitiator (TPO).

TABLE 4

Comparative Example 2

Thermal Curing and Coating Film Analysis of Urushiol Polymers

4 g of acetone was added to 1 g of the urushiol polymer obtained in Example 2, followed by dissolving well, spraying it onto a polished stainless plate, and thermally curing them in a dryer at 150 ° C., respectively. The change in hardness was measured after standing, and the results are shown in Table 5.

TABLE 5

Comparative Example 3

Photocuring and Coating Film Characterization of Urushiol Polymer by Photovoltaic

Two samples of 3 g of urushiol polymer obtained in Example 2 were prepared, and 5 wt% (0.15 g) of photoinitiator (TPO) was added to one of them, followed by addition of 9 g of acetone, followed by stirring. Spray-coated to cure for 5 hours under sunlight, the surface temperature was 10 ℃. After characterizing the coating film, the mixture was left at room temperature for 5 days, and the characteristics of the coating film were examined again. Table 6 shows. As a control, the coating film was cured and analyzed under the same conditions without adding a photoinitiator.

TABLE 6

Example 7

Skin allergy experiment of yellow lacquer

1 wt% and 10 wt% acetone solution were prepared from the urushiol polymer prepared in Example 2 and the sulfur lacquer obtained in Example 3, and then two 1 cm circles and 1 wt% solution were placed on the wrist of the researcher sensitive to lacquer allergic reaction. 1 drops of urushiol polymer and sulfur lacquer were applied to the skin, respectively, and then dried as it was to confirm the skin allergic reaction, and 10 wt% solution was also tested in the same manner. As a result, the 1 wt% solution did not react with urushiol polymer and sulfur lacquer, but in the 10 wt% solution, urushiol polymer showed red spots after 2 days, but the sulfur lacquer did not cause allergic reaction. 3 is an allergic reaction result of 10% sulfur lacquer raw material and sulfur lacquer. The part drawn with circles is covered with yellow lacquer, and the red spots are covered with 10% by weight urushiol polymer.

The sulfur lacquer prepared by the manufacturing method according to the present invention has a very low production cost compared to the yellow lacquer, does not cause skin allergy, has excellent physical and chemical properties, and also hardens compared to the methods used in existing industrial fields. It is very fast and has the advantage of excellent coating properties.

The sulfur lacquer prepared by the manufacturing method according to the present invention is natural when it is painted on a metal having a white luster such as stainless steel, aluminum, silver, chromium, nickel, zinc, or a metal such as brass, copper, 14-24K, etc. It has the property of expressing a soft and brilliant golden color. In addition, it is transparent and can be used for materials other than metal such as wood or plastic, and it is possible to reduce expensive pollution and complex process caused by gold plating as well as to replace expensive yellow lacquer and gold imports, and to develop inexpensive jewelry and high value-added luxury products.

Claims (8)

a) preparing a urushiol polymer by reacting 65 to 95% by weight of urushiol extracted from a natural lacquer solution with 5 to 35% by weight of formaldehyde in a mixed solution of water and a polar solvent in the presence of a basic catalyst; b) 30 to 70% by weight of the urushiol polymer prepared in step a) and acrylate monomer having at least one acryl group and 70 to 30% by weight of acrylate oligomer in an organic solvent in the presence of an acid catalyst selected from organic or inorganic acids. Reacting to produce a lacquer; A method of manufacturing sulfur lacquer, characterized in that. The method of claim 1, The acrylate monomer having an acryl group and the acrylate oligomer include C1-C5 alkyl acrylate, C1-C5 alkyl methacrylate, melamine acrylate, epoxy acrylate, polyester acrylate, urethane acrylate and spiran acrylate. Method for producing sulfur lacquer, characterized in that at least one selected from. The method of claim 1, The basic catalyst used in step a) is a method for producing sulfur lacquer, characterized in that at least one selected from ammonia water, triethylamine, triethanolamine, dimethanolamine. The method according to claim 2 or 3, Formaldehyde used in step a) is a method for producing sulfur lacquer, characterized in that formalin. The method of claim 4, wherein The reaction in step a) is a method for producing sulfur lacquer, characterized in that the reaction is refluxed in a solvent mixture of water and ethanol to precipitate separated into a urushiol polymer having a number average molecular weight of 2000 to 2500. The method of claim 5, The reaction of step b) is carried out by refluxing in at least one organic solvent selected from n-hexane, benzene, toluene, THF, and then removing the reaction solvent to produce sulfur lacquer having a number average molecular weight of 2100 to 2600. Method of manufacturing lacquer. A method of forming a sulfur lacquer coating, characterized in that the sulfur lacquer prepared according to the method according to claim 1 is dissolved in a polar organic solvent and applied to a member for forming a coating film, followed by photocuring or thermal curing. The method of claim 7, wherein A method for forming a sulfur lacquer coating, comprising adding 93 to 99.9% by weight of sulfur lacquer and 0.1 to 7% by weight of a photocuring initiator or a thermal polymerization initiator.

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