4-disubstituted aminobenzyl subunit camphorsulfonic acid as well as synthesis method and application thereof

Abstract

The invention relates to a water-soluble ultraviolet absorbent 4-disubstituted aminobenzyl subunit camphorsulfonic acid and a synthesis method and application thereof, and the synthesis method comprises the following steps: in a toluene-methanol mixed solvent, carrying out heating reflux reaction on camphorsulfonic acid and 2 equivalent weight of sodium methoxide, and after enolation conversion is completed, carrying out reduced pressure distillation to obtain the 4-disubstituted aminobenzyl subunit camphorsulfonic acid. Slowly dropwise adding a corresponding 4-disubstituted aminobenzaldehyde solution with the molar weight equal to that of camphorsulfonic acid, continuously heating and stirring to react for 6-12 hours, adding water to terminate the reaction, acidifying the reaction solution by using hydrochloric acid or sulfonic acid type cation exchange resin, separating to remove methylbenzene, adjusting the pH value of a water phase to about 6.5, performing rotary evaporation dehydration under reduced pressure, and extracting a crude product by using a conventional method; a target product can be obtained through column chromatography purification, and the target product not only has water solubility, but also has the characteristic of absorbing UVA and UVB ultraviolet light at the same time; the composition can be applied to sun-screening agent products, cosmetics or home care products, and also can be applied to various industrial products such as paint, varnish, plastics, textiles and rubber to improve the light resistance of the industrial products.

Description

Technical Field

[0001] This invention pertains to the chemical synthesis technology of ultraviolet absorbers, specifically relating to a water-soluble ultraviolet absorber, 4-disubstituted aminobenzyl camphorsulfonic acid, its synthesis method, and its uses. Background Technology

[0002] Sunlight's ultraviolet radiation is categorized by wavelength into short-wave ultraviolet (UVC, 200–280 nm), medium-wave ultraviolet (UVB, 280–320 nm), and long-wave ultraviolet (UVA, 300–400 nm). All wavelengths of ultraviolet radiation can potentially damage human skin. Because UVC is absorbed by ozone in the atmosphere and rarely reaches the Earth's surface, people focus more on protection against UVA and UVB. UVB can cause severe photodamage to the skin's surface, leading to vasodilation in the dermis and symptoms such as redness and blisters. Prolonged exposure can result in erythema, inflammation, and skin aging; in severe cases, it can cause skin cancer, making it a key area for prevention. UVA can penetrate deep into the dermis and affect melanin in the epidermis, causing melanin deposition and darkening of the skin. While UVA does not cause acute skin inflammation and its effects are slow, it can accumulate over time and enhance the side effects of UVB, contributing to skin aging and severe damage.

[0003] To prevent or mitigate skin damage caused by sun exposure, people use various cosmetics containing sunscreens to protect against ultraviolet (UV) radiation. Sunscreens primarily fall into two categories: physical UV shields and organic UV absorbers. Commonly used physical UV shields include titanium dioxide, zinc oxide, kaolin, talc, and iron oxide. However, these can sometimes cause issues such as makeup settling into fine lines, powdery residue, and a slightly heavy texture. Most common sunscreens incorporate various organic UV absorbers to achieve UV protection. Organic UV absorbers are organic compounds with long conjugated chemical structures. Because the molecular structure of a single UV absorber is fixed, its UV absorption peak typically has only one main absorption peak within the UVA and UVB bands. Therefore, to achieve broad-spectrum UV protection, sunscreens are usually formulated with a combination of two or more organic UV absorbers. Meanwhile, compounds with long conjugated chemical structural segments are usually hydrophobic, and most organic ultraviolet absorbers are also hydrophobic. When used in sunscreen chemicals, they are prone to problems such as poor stability, easy precipitation, and short shelf life, especially when used in water-based cosmetics. The development and application of water-based ultraviolet absorbers can greatly improve these problems. At present, the research and development of novel water-soluble ultraviolet absorbers has been one of the hot topics in the development of organic ultraviolet absorbers. Therefore, the research and development of a novel water-soluble ultraviolet absorber that can protect against both UVA and UVB ultraviolet rays is a very meaningful and economically beneficial research work. Summary of the Invention

[0004] The purpose of this invention is to provide 4-disubstituted aminobenzyl camphorsulfonic acid, its synthesis method and uses, wherein the 4-disubstituted aminobenzyl camphorsulfonic acid is used as a water-soluble ultraviolet absorber, which has the effect of absorbing both UVA and UVB ultraviolet rays.

[0005] Countries worldwide have strict regulations regarding sunscreens used in cosmetics. According to the "Cosmetic Safety Technical Specifications" (2015 edition), my country permits the use of 27 types of sunscreens (including titanium dioxide and zinc oxide sunscreens). Among these, 25 are chemical sunscreens, including six benzylidene camphor-based organic UV absorbers: 3-benzylidene camphor, 4-methylbenzylidene camphor, camphor benzalkonium methyl sulfate, benzylidene camphor sulfonic acid and its salts, polyacrylamide methylbenzylidene camphor, and terephthalamide dicamphor sulfonic acid and its salts. Benzylidene camphor-based organic UV absorbers with a camphor ring structure exhibit significant advantages in chemical stability and poor skin penetration. Based on this structure, this patent designs and synthesizes a water-soluble UV absorber, 4-disubstituted aminobenzylidene camphor sulfonic acid. The structural characteristics of this UV absorber are as follows:

[0006] R1 and R2 can be substituents such as methyl, ethyl, and phenyl. Such ultraviolet absorbers are not only water-soluble, but also have the characteristic of absorbing both UVA and UVB ultraviolet light.

[0007] The synthesis scheme of 4-disubstituted aminobenzyl camphorsulfonic acid provided by this invention is as follows: Camphorsulfonic acid and 2 equivalents of sodium methoxide are heated under reflux in a toluene-methanol mixed solvent to complete the enolization conversion. Then, an equimolar amount of the corresponding 4-disubstituted aminobenzaldehyde solution of camphorsulfonic acid is slowly added dropwise, and the reaction is continued under reflux and stirring for 6-12 h. The reaction is terminated by adding water. The reaction solution is acidified with hydrochloric acid or sulfonic acid-type cation exchange resin to separate and remove toluene. The pH of the aqueous phase is adjusted to about 6.5. After dehydration by rotary evaporation under reduced pressure, the crude product is extracted by conventional methods. The target product is obtained by column chromatography purification. The reaction equation is as follows:

[0008] In this invention, camphor sulfonic acid and 4-disubstituted aminobenzaldehyde are used in an equimolar ratio, and the alkali used in the reaction is sodium methoxide, the amount of which is 2.0 equivalents of camphor sulfonic acid.

[0009] The preferred solvent for the reaction in this invention is toluene, and an appropriate amount of methanol is added as a co-solvent, wherein the volume ratio of toluene to methanol is 9~10:1.

[0010] The reaction of this invention is carried out under reflux conditions. Camphor sulfonic acid and 2 equivalents of sodium methoxide are heated under reflux in a toluene-methanol mixed solvent. When the reaction solution is almost clear, it indicates that the enolization conversion is complete. At this time, an equimolar amount of the corresponding 4-disubstituted aminobenzaldehyde solution of camphor sulfonic acid can be slowly added dropwise. After the addition is complete, the external bath temperature is appropriately increased to 90~95℃. The reaction time is 6~12 h. After the reaction is completed, water can be added to terminate the reaction.

[0011] The target product of this invention, 4-disubstituted aminobenzyl camphorsulfonic acid, is an amphoteric compound. Its separation and purification require acidification of the reaction solution, using hydrochloric acid or a sulfonic acid-type cation exchange resin. Toluene is separated from the reaction solution acidified with hydrochloric acid, and the pH of the aqueous phase is adjusted to 6.5 ± 0.5. The solution is then dehydrated by rotary evaporation under reduced pressure, and the crude product is extracted with methanol. Alternatively, when the reaction solution is acidified with a sulfonic acid-type cation exchange resin, the pH can be directly adjusted to 6.5 ± 0.5. After filtering through the resin, the crude product is obtained by rotary evaporation under reduced pressure.

[0012] The crude product of the target compound of this invention can be purified by silica gel column chromatography, which uses dichloromethane-methanol as the eluent for gradient elution. If the sodium ion content in the product obtained by column chromatography is high, a sulfonic acid-type cation exchange resin column can be used for treatment. After ion exchange, the product is at its isoelectric point.

[0013] Surprisingly, the target product, 4-disubstituted aminobenzyl camphorsulfonic acid, exhibits two UV absorption peaks near its isoelectric point, located in the UVA and UVB regions respectively. This indicates that this type of UV absorber has the ability to simultaneously absorb UVA and UVB light. The reason for this is that the target product, 4-disubstituted aminobenzyl camphorsulfonic acid, is an amphoteric compound. At its isoelectric point, it exists in a balance system of quaternary ammonium salt ammonium ions and amino nitrogen lone pair electrons conjugated with the benzene ring, forming an ammonium ion equilibrium system. Therefore, the phenomenon of two UV absorption peaks appears. The schematic diagram of its equilibrium reaction is shown below:

[0014] This theoretical analysis can be verified through acid-base neutralization experiments. Taking 4-diethylaminobenzylcamphorsulfonic acid, which is highly sensitive to acids and bases, as an example, a 0.1 mmol / L methanol solution was prepared, and its UV absorption peak was measured using a Shimadzu UV-2700 ultraviolet spectrometer. max =282 nm (ε=12880); 386 nm (ε=14180); When 1.0 eq of hydrochloric acid is added to the above methanol solution for neutralization, its ultraviolet absorption peak changes to λ. max =290 nm (ε=13890); 390 nm (ε=940), indicating that it exists mainly in the form of quaternary ammonium salt ammonium ions; however, when 1.0 eq sodium hydroxide is added to the above methanol solution for neutralization, its ultraviolet absorption peak changes to λ. max =253 nm (ε=5150); 395 nm (ε=16280), indicating that it exists mainly in the form of amino-onium ions. Furthermore, when the amino substituent of 4-diphenylaminobenzyl camphorsulfonic acid contains a phenyl group, the conjugation effect of the benzene ring significantly reduces the electron-donating ability of the amino nitrogen lone pair, and the compound becomes insensitive to acid and base effects. For example, when 4-diphenylaminobenzyl camphorsulfonic acid is prepared into a 0.1 mmol / L methanol solution, its UV absorption peak is measured to be λ using a Shimadzu UV-2700 UV spectrometer. max =290 nm (ε=12600); 389 nm (ε=20360); When 1.0 eq of hydrochloric acid is added to the above methanol solution for neutralization, its UV absorption peak changes to λ. max =291 nm (ε=10440); 388 nm (ε=16820); and when 1.0 eq sodium hydroxide is added to the above methanol solution for neutralization, its ultraviolet absorption peak changes to λ. max =291 nm (ε=12500); 389 nm (ε=19810), indicating that 4-diphenylaminobenzyl camphorsulfonic acid always exists in a balanced form of quaternary ammonium salt ammonium ions and ammonium ions, and has a relatively stable ability to absorb UVA and UVB ultraviolet light simultaneously.

[0015] The present invention also provides the use of 4-disubstituted aminobenzyl camphorsulfonic acid as a water-soluble ultraviolet absorber in the preparation of sunscreen products, cosmetics or household care products, or as a lightfastness additive in the preparation of paints, varnishes, plastics, textiles or rubber.

[0016] Compared with existing common UV absorbers, the present invention is characterized by the fact that the 4-disubstituted aminobenzyl camphorsulfonic acid UV absorber is not only water-soluble, but also has a broad-spectrum UV protection effect that absorbs UVA and UVB ultraviolet light. It is expected to be used in sunscreen products, cosmetics or household care products, and also in various industrial products such as paints, varnishes, plastics, textiles and rubber to improve their lightfastness. Attached Figure Description

[0017] Figure 1 This is the ultraviolet absorption spectrum of 4-disubstituted aminobenzyl camphorsulfonic acid of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will be further described in detail below through specific embodiments. However, the present invention is not limited to these embodiments. The preparation process under other conditions can be achieved by referring to the method of the following embodiments. Example

[0019] 4.65 g camphorsulfonic acid (0.02 mol) and 2.21 g sodium methoxide (0.04 mol) were added to a reaction flask containing 40 mL toluene and 4 mL methanol, and the mixture was stirred at 85 °C in an external bath for 1 h. 3.54 g of p-diethylaminobenzaldehyde (0.02 mol) was dissolved in a mixture of 9 mL toluene and 2.5 mL methanol, and slowly added dropwise to the reaction system over approximately 1 hour. The external bath temperature was raised to 90-95 °C, and the reaction was refluxed for 12 hours. 20 mL of water and 20 mL of concentrated hydrochloric acid were added separately, and the mixture was stirred to separate the toluene phase. The aqueous phase was neutralized with a 10% sodium hydroxide solution, and the pH was adjusted to approximately 6.5. A small amount of solid precipitated. The aqueous solution was evaporated under reduced pressure, and the product was extracted twice with methanol. The methanol phases were combined, and the solvent was removed by rotary evaporation under reduced pressure to obtain the crude product. This crude product was purified by silica gel column chromatography (using a gradient elution with dichloromethane-methanol as the eluent) to obtain 5.82 g of the target product, 4-diethylaminobenzylmethylene camphorsulfonic acid, with a yield of 74.3% (UV absorption spectrum as shown). Figure 1 (As shown in (A)). 1 H NMR (400 MHz, DMSO- d6) δ 7.37 (d, J = 9.0 Hz, 2H), 6.95 (s, 1H), 6.79 (d, J = 9.0 Hz, 2H), 3.38 (q, J = 7.0 Hz, 4H), 3.17 (d, J = 4.6 Hz, 1H), 3.00 (d, J = 4.6 Hz, 1H), 2.85 - 2.74 (m, 1H), 2.15 - 2.05 (m, 1H), 1.41 - 1.29 (m, 2H), 1.11 (s, 3H), 1.10 (t, J = 7.0 Hz, 6H), 0.71 (s, 3H). 13 C NMR (100 MHz, DMSO - d 6) δ 206.01, 148.44, 136.60, 132.13, 128.24, 121.84, 111.77, 57.88, 49.11, 49.08, 47.73, 47.43, 44.20, 25.96, 25.78, 20.80, 19.96, 12.91. FT - IR (film): 3445, 2966, 1713, 1631, 1230, 1195, 1049, 951, 919, 878, 813 cm -1 , HRMS(ESI) [M + H] + : calcd for C 21 H 30 NO4S: 392.1890, found 392.1941。

[0020] Example 2: 1.86 g camphorsulfonic acid (8 mmol) and 0.88 g sodium methoxide (16 mmol) were added to a reaction flask containing 16 mL toluene and 1.6 mL methanol, and the mixture was stirred in an external bath at 85 °C for 1 h. Then, 2.23 g of p-diphenylaminobenzaldehyde (8 mmol) was dissolved in a mixed solvent of 4.5 mL toluene and 1 mL methanol, and slowly added dropwise to the above reaction system. The addition was completed in about 1 h. The external bath temperature was raised to 95 °C, and the reaction was continued under reflux for 9 h. 20 mL of water was added and stirred to separate the toluene phase. 10 mL of sulfonic acid-type cation exchange resin (>5.0 mmol / mL) was added to the aqueous phase and stirred for about 30 min. At this time, the pH of the aqueous solution reached about 6.5. The resin was filtered off, and the aqueous solution was evaporated under reduced pressure to obtain the crude product. This crude product was purified by silica gel column chromatography (using dichloromethane-methanol as the eluent gradient elution) to obtain 2.65 g of the brownish-yellow solid product 4-diphenylaminobenzyl camphorsulfonic acid, with a yield of 67.9% (UV absorption spectrum as shown). Figure 1 (as shown in (B)). 1H NMR (400 MHz, DMSO-d6) δ 7.47 (d, J = 7.5 Hz, 4H), 7.37 (t,J = 7.5 Hz, 4H), 7.14 (t, J=7.5 Hz, 2H), 7.08 (d, J = 8.8 Hz, 2H), 7.01 (s,1H), 6.93 (t, J = 8.8 Hz, 2H), 3.07 (d, J=14.7 Hz, 1H), 3.06 (s,1H), 2.81~2.69 (m, 1H), 2.51 (d, J=14.7 Hz, 1H), 2.19 ~2.07 (m, 1H), 1.45~1.34 (m, 2H),1.09 (s, 3H), 0.71 (s, 3H). 13C NMR (100 MHz, DMSO-d6) δ 206.15, 148.53,146.85, 139.77, 131.61, 130.25, 128.44, 127.15, 125.41, 124.60, 121.75,57.81, 48.81, 47.62, 47.17, 25.84, 25.47, 20.73, 19.55. FT-IR (film): 3432,2956, 1719, 1641, 1325, 1171, 1050, 954, 919, 830, 754 cm -1 ;HRMS(ESI)[M+K]+:calcd for C29H29KNO4S:526.1454, found 526.1281.

[0021] Example 3 1.54 g camphorsulfonic acid (6.6 mmol) and 0.73 g sodium methoxide (13.2 mmol) were added to a reaction flask containing 13 mL toluene and 1.3 mL methanol, and the mixture was stirred in an external bath at 85 °C for 1 h. Then, 1.40 g of N-methyldiphenylamine benzaldehyde (6.6 mmol) was dissolved in a mixed solvent of 4.5 mL toluene and 1 mL methanol, and slowly added dropwise to the above reaction system. The addition was completed in about 1 h. The external bath temperature was raised to 90 °C, and the reaction was continued under reflux for 6 h. 20 mL of water was added and stirred to separate the toluene phase. 10 mL of sulfonic acid-type cation exchange resin (>5.0 mmol / mL) was added to the aqueous phase and stirred for about 30 min. At this time, the pH of the aqueous solution reached about 6.5. The resin was filtered off, and the aqueous solution was evaporated under reduced pressure to obtain the crude product. This crude product was purified by silica gel column chromatography (using dichloromethane-methanol as the eluent gradient elution) to obtain 2.05 g of the brownish-yellow solid product 4-N-methylanilinebenzyl camphorsulfonic acid, with a yield of 72.7% (UV absorption spectrum as shown). Figure 1 (as shown in (C)). 1H NMR (400 MHz, DMSO-d6) δ 7.41 (d, J = 8.8Hz, 2H), 7.37 (d, J = 7.5 Hz, 2H), 7.17 (d, J = 7.5 Hz, 2H), 7.13 (t, J = 7.5Hz, 1H), 6.98 (s, 1H), 6.87 (d, J = 8.8 Hz, 2H), 3.29 (s, 3H), 3.04 (d, J =14.8 Hz, 1H), 3.00 (s,1H), 2.51 (d, J = 14.8 Hz, 1H), 2.15 ~2.07 (m, 1H),1.42~1.30 (m, 2H), 1.08 (s, 3H), 0.69 (s, 3H).13C NMR (100 MHz, DMSO-d6) δ206.04, 149.67, 148.06, 138.79, 131.52, 130.08, 127.44, 126.05, 124.31,124.25, 116.92, 58.03, 49.10, 47.58, 47.41, 25.95, 25.71, 20.84, 19.89. FT-IR(film): 3397, 2924, 1714, 1348, 1177, 1050, 951, 872, 823,759cm -1.HRMS(ESI)[MH]-: calcd for C24H26NO4S:424.1588, found 424.1643.

[0022] Experimental Example 1 Weigh 0.0196 g of the UV absorber 4-diethylaminobenzyl camphorsulfonic acid, dissolve it in an appropriate amount of methanol, pour the solution into a 50 mL volumetric flask and dilute to 50 mL. Shake well, then take 5 mL of the solution and pour it into another 50 mL volumetric flask and dilute to 50 mL to prepare a 0.1 mmol / L methanol solution. Measure the absorbance in the wavelength range of 200–800 nm using a Shimadzu UV-2700 UV spectrometer. The UV spectrum is shown below. Figure 1 -A.

[0023] Experimental Example 2 Weigh 0.0244 g of the UV absorber 4-diphenylaminobenzyl camphorsulfonic acid, dissolve it in an appropriate amount of methanol, pour the solution into a 50 mL volumetric flask and dilute to 50 mL. Shake well, then take 5 mL of the solution and pour it into another 50 mL volumetric flask and dilute to 50 mL to prepare a 0.1 mmol / L methanol solution. Measure the absorbance in the wavelength range of 200–800 nm using a Shimadzu UV-2700 UV spectrometer. The UV spectrum is shown below. Figure 1 -B.

[0024] Experimental Example 3 Weigh 0.0213 g of the UV absorber 4-N-methylanilinebenzyl camphorsulfonic acid, dissolve it in an appropriate amount of methanol, pour the solution into a 50 mL volumetric flask and dilute to 50 mL. Shake well, then take 5 mL of the solution and pour it into another 50 mL volumetric flask and dilute to 50 mL to prepare a 0.1 mmol / L methanol solution. Measure the absorbance in the wavelength range of 200–800 nm using a Shimadzu UV-2700 UV spectrometer. The UV spectrum is shown below. Figure 1 -C.

[0025] Application Example 1 A method for preparing a sunscreen agent, the specific input amounts of each raw material are detailed in Table 1:

[0026] The preparation process includes the following steps: (1) Add 1,4-butanediol, ethylhexylglycerin, 4-diphenylaminobenzyl camphorsulfonic acid and water to a pot, heat to 80 ℃ and stir evenly, then add carbomer 940, mix with a homogenizer and keep warm for later use; (2) Add caprylic / capric triglyceride, octocrylene, humosasulfate, methylparaben, titanium dioxide and polyhydroxystearic acid to a pot, heat to 80 ℃ and stir evenly, keep warm for later use; (3) Add the oil phase to the aqueous phase dropwise and mix with a homogenizer to obtain the sunscreen product. The sunscreen product was tested using conventional methods and the results showed that when the pH value was 6.5~7.0 and the application amount was 2.0 mg / cm2, the ultraviolet absorption rate reached 97.8%, the critical wavelength λc was 400 nm, and the UVA / UVB value was 0.61. The results indicate that this sunscreen product can effectively protect against long-wave and medium-wave ultraviolet rays.

[0027] Application Example 2 A method for preparing a UV-protective coating for glass, the specific input amounts of each raw material are detailed in Table 2:

[0028] The preparation process includes the following steps: (1) DISPERBYK-190, polydimethylsiloxane, alkylphenol polyoxyethylene ether, HY-304 associative polyurethane, alcohol ester dodecyl, and DT-650 polyether modified silicone are mixed and stirred evenly to obtain the additives for later use; (2) 4-diphenylaminobenzyl camphor sulfonic acid and phenylbenzimidazole sulfonic acid are dissolved in water and then added dropwise to styrene-acrylic emulsion and stirred evenly. Then titanium dioxide and additives are added and stirred evenly to obtain a coating with ultraviolet absorption properties. The prepared glass coating is coated on the glass surface and cured at room temperature to form a coating. The performance of the coating is tested, and the results are as follows: when the dry film thickness is about 16 μm, the visible light transmittance is 88.4% and the ultraviolet absorption rate is 92.6%. The coating formed by the prepared coating has good visible light transmittance and high ultraviolet absorption rate, which can effectively block ultraviolet rays.

Claims

1,4-Disubstituted aminobenzyl camphorsulfonic acid has the following structural characteristics: R1 and R2 are methyl, ethyl or phenyl.

2. The method for synthesizing 4-disubstituted aminobenzyl camphorsulfonic acid according to claim 1, comprising the following steps: in a toluene-methanol mixed solvent, camphorsulfonic acid is heated and refluxed with 2 equivalents of sodium methoxide to complete the enolization conversion, and then an equimolar amount of 4-disubstituted aminobenzaldehyde solution of camphorsulfonic acid is slowly added dropwise. After the addition of the 4-disubstituted aminobenzaldehyde solution, the reaction is continued to be heated and stirred for 6-12 h. The reaction is terminated by adding water, and the reaction solution is acidified with hydrochloric acid or sulfonic acid-type cation exchange resin to separate and remove toluene. The pH of the aqueous phase is adjusted to 6.5±0.5, and after dehydration by rotary evaporation under reduced pressure, the target product is obtained by column chromatography purification.

3. The synthesis method according to claim 2, characterized in that: The volume ratio of toluene to methanol solvent is 9~10:

1.

4. The method according to claim 2, characterized in that: The heating and stirring reaction after adding the 4-disubstituted aminobenzaldehyde solution was carried out under external heating at a temperature of 90-95°C.

5. The synthesis method according to claim 2, characterized in that: The column chromatography used was silica gel column chromatography, which employed a gradient elution with dichloromethane-methanol as the eluent.

6. The use of the 4-disubstituted aminobenzyl camphorsulfonic acid according to claim 1 as a water-soluble ultraviolet absorber in the preparation of sunscreen products or cosmetics.

7. Use of the 4-disubstituted aminobenzyl camphorsulfonic acid of claim 1 as a lightfastness additive in the preparation of paints, varnishes, plastics, textiles or rubber.

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