Resin composition, molded body, and cosmetic container

Abstract

To provide a resin containing a copolymer of an aromatic vinyl monomer and a cyano-based monomer, which has chemical resistance and has high transparency and high color tone, as a raw material for a cosmetic container or the like that particularly requires high designability. According to the present invention, a resin composition containing a resin (A) containing a copolymer of an aromatic vinyl monomer and a cyano-based monomer, an antioxidant (B) having 3 or more phenol sites in total within a molecule, and a phosphorus-based antioxidant (C) is provided.

Description

Technical Field

[0001] This invention relates to resin compositions containing copolymers of aromatic vinyl monomers and cyano monomers, molded articles thereof, and cosmetic containers. Background Technology

[0002] Copolymers containing aromatic vinyl monomers and cyano monomers possess excellent chemical resistance, rigidity, and moldability, and are therefore widely used in various fields. However, thermoplastic copolymers with cyano monomers as the sole component are prone to color degradation due to the high temperatures during molding. This results in low transparency and a lack of gloss in the actual molded product.

[0003] To address the aforementioned issues, methods have been proposed including: using initiators with low dehydrogenation capacity during polymerization (Patent Document 1); adding antioxidants with two phenolic sites within the molecule during polymerization stages with a polymerization rate of 60% or higher (Patent Document 2); and using peroxide tert-amyl esters that do not contain aromatic rings when copolymerizing acrylonitrile monomers with styrene monomers (Patent Document 3).

[0004] [Existing Technical Documents]

[0005] [Patent Documents]

[0006] Patent Document 1: Japanese Patent Application Publication No. 4-146908

[0007] Patent Document 2: Japanese Patent Application Publication No. 4-146907

[0008] Patent Document 3: Japanese Patent Application Publication No. 8-301913 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] However, these methods cannot adequately improve hue, especially for raw materials used in cosmetic containers and other applications requiring high design sophistication, as they fail to produce resins with satisfactory transparency and hue.

[0011] Therefore, the objective of this invention is to provide a resin containing a copolymer of aromatic vinyl monomers and cyano monomers, which is particularly suitable as a raw material for cosmetic containers and the like, requiring high design flexibility, and whose molded articles, after molding processing, have chemical resistance and can have high transparency and high color tint.

[0012] Solution for solving the problem

[0013] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that the following implementation method is effective.

[0014] (1) In one embodiment of the resin composition of the present invention, the resin composition comprises: a resin (A) comprising a copolymer of an aromatic vinyl monomer and a cyano monomer; an antioxidant (B) having a total of three or more phenolic sites in the molecule; and a phosphorus-based antioxidant (C).

[0015] (2) In another embodiment of the resin composition involved in the present invention, the total content of antioxidant (B) and antioxidant (C) is 0.01 to 0.5 parts by weight relative to 100 parts by weight of resin (A).

[0016] (3) In another embodiment of the resin composition involved in the present invention, the copolymer of aromatic vinyl monomer and cyano monomer contains 40-95% by mass of the aromatic vinyl monomer unit and 5-60% by mass of the cyano monomer unit when the total of the aromatic vinyl monomer and cyano monomer is set to 100% by mass.

[0017] (4) In another embodiment of the resin composition involved in the present invention, it is a molded body formed from any one of the resin compositions (1) to (3).

[0018] (5) In another embodiment of the resin composition involved in the present invention, it is a cosmetic container formed from any one of the resin compositions (1) to (3).

[0019] The effects of the invention

[0020] According to the present invention, a resin with chemical resistance, high transparency, and high color tint is provided. This resin composition can be used in cosmetic containers and the like, where high design flexibility is required. Detailed Implementation

[0021] The resin composition of the present invention comprises: a resin (A) containing a copolymer of an aromatic vinyl monomer and a cyano monomer; an antioxidant (B) having a total of three or more phenolic sites in the molecule; and a phosphorus-based antioxidant (C).

[0022] The resin (A) in this invention is a resin whose main component is a copolymer of aromatic vinyl monomers and cyano monomers. The content of the copolymer of aromatic vinyl monomers and cyano monomers in 100% by mass of resin (A) is, for example, 50% by mass or more. In one embodiment, the content of the copolymer in resin (A) is preferably 80% by mass or more, more preferably 80% by mass or more, and even more preferably, resin (A) is substantially composed only of a copolymer of aromatic vinyl monomers and cyano monomers.

[0023] As aromatic vinyl monomers, there are no particular limitations, but examples include substituted styrene with substituents such as styrene, α-methylstyrene, p-methylstyrene, 3,5-dimethylstyrene, 4-methoxystyrene, and 2-hydroxystyrene; halogenated styrene such as α-bromostyrene and 2,4-dichlorostyrene; and 1-vinylnaphthalene.

[0024] As cyano monomers, there are no particular limitations; examples include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, and α-ethylacrylonitrile.

[0025] The antioxidant (B) of this invention is important because it has a total of three or more phenolic sites within the basic framework and intramolecularly. If it has two or fewer, the antioxidant capacity is insufficient, which will cause resin deterioration during molding and result in poor color.

[0026] The antioxidants (B) that can be used in this invention specifically include triphenols such as 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 4,4',4”-(1-methylpropionyl-3-ylidene)tris(6-tert-butyl-m-cresol), and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene; tetraphenols such as pentaerythritol-tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; etc., and one of them can be used alone or two or more can be used in combination.

[0027] Examples of the phosphorus-based antioxidants (C) of the present invention include, for example, trinonylphenyl phosphite, triphenyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite, cyclopentanetetraylbis(2,4-di-tert-butylphenyl) phosphite, cyclopentanetetraylbis(octadecyl phosphite), cyclopentanetetraylbis(nonylphenyl) phosphite, tris(mono- and dinonylphenyl mixed) phosphite, 4,4'-isopropenylalkyl (C12-C15) phosphite, diphenylisooctyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, triisodecyl phosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, and 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite. One type can be used alone or in combination of two or more types.

[0028] In this embodiment, the total content of antioxidant (B) and phosphorus-based antioxidant (C) relative to 100 parts by weight of resin (A) is preferably 0.01 to 0.50 parts by weight, more preferably 0.05 to 0.40 parts by weight, and even more preferably 0.10 to 0.30 parts by weight. Specifically, for example, it is 0.01, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, or 0.50 parts by weight, or it can be within any two values ​​exemplified herein. If the total content of antioxidant (B) and phosphorus-based antioxidant (C) exceeds 0.50 parts by weight, the heat resistance of the resulting resin composition may decrease. In addition, if the total content of antioxidant (B) and phosphorus-based antioxidant (C) is less than 0.01 parts by weight, the color change of the resulting molded article cannot be suppressed.

[0029] Furthermore, the mixing ratio of antioxidant (B) to phosphorus-based antioxidant (C) is not particularly limited. The mass ratio of antioxidant (B) to phosphorus-based antioxidant (C) is preferably 5 / 1 to 1 / 5, more preferably 4 / 1 to 1 / 4. Specifically, for example, it is 5 / 1, 4 / 1, 3 / 1, 2 / 1, 1 / 1, 1 / 2, 1 / 3, 1 / 4 or 1 / 5, or it can be within any two values ​​exemplified here. By making the mixing ratio of antioxidant (B) to phosphorus-based antioxidant (C) 5 / 1 to 1 / 5 by mass, the color variation of the resulting molded article can be effectively suppressed.

[0030] As a method for adding antioxidant (B) and phosphorus-based antioxidant (C), examples include adding and mixing them during the polymerization, devolatilization, or granulation process of resin (A); or adding and mixing them using an extruder or injection molding machine during molding processing, etc., without particular limitation.

[0031] The ratio of aromatic vinyl monomers to cyano monomers in resin (A) can be arbitrarily selected. The amount of aromatic vinyl monomers in 100% by mass copolymer is preferably 40% to 95% by mass, more preferably 50% to 85% by mass, and even more preferably 70% to 85% by mass. Specifically, for example, it is 40, 50, 60, 65, 70, 75, 80, 85, 90, or 95% by mass, or any two values ​​exemplified herein. The amount of cyano monomers in 100% by mass copolymer is preferably 5% to 60% by mass, more preferably 15% to 50% by mass, and even more preferably 15% to 70% by mass. Specifically, for example, it is 5, 10, 15, 20, 35, 40, 50, or 60% by mass, or any two values ​​exemplified herein. If the monomers are outside the above composition range, it is difficult to achieve the appearance, chemical resistance, transparency, mechanical properties, etc., of the molded article as the object of this invention.

[0032] As a method for manufacturing resin (A) containing a copolymer of aromatic vinyl monomers and cyano monomers in this invention, suspension polymerization, solution polymerization, bulk polymerization, etc. can be used. From the purpose of preventing dispersants and the like from being mixed into the resin, solution polymerization or bulk polymerization is preferred.

[0033] Resin (A) can be copolymerized with copolymerizable monomers other than cyano monomers and aromatic vinyl monomers, within a range that does not impede the effects of the present invention. Examples of other vinyl compounds that can copolymerize with cyano monomers and aromatic vinyl monomers include acrylates such as methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate; unsaturated carboxylic acids or their anhydrides such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid; and imide compounds such as N-phenylmaleimide and N-cyclohexylmaleimide. Ethyl acrylate and butyl acrylate are particularly preferred, and mixtures of two or more may also be used.

[0034] When the total of cyano monomers, aromatic vinyl monomers and monomers that can copolymerize with them is set to 100% by mass, the content of these monomers is 0% to 20% by mass, preferably 0% to 10% by mass.

[0035] In the manufacture of resin (A), molecular weight regulators such as tert-dodecyl mercaptan, n-dodecyl mercaptan, unsaturated dimers of α-methylstyrene, terpinene, and octyl mercaptoacetate can be used.

[0036] The resin composition of the present invention may also contain mineral oil within a range that does not impair the effects of the present invention. Additionally, it may contain additives such as stearic acid, ethylene bis-stearamide, internal lubricants, sulfur-based antioxidants, lactone-based antioxidants, ultraviolet absorbers, hindered amine stabilizers, antistatic agents, and external lubricants.

[0037] Ultraviolet (UV) absorbers have the function of inhibiting degradation and discoloration caused by UV radiation. Examples of UV absorbers include benzophenone-based, benzotriazole-based, triazine-based, benzoate-based, salicylate-based, cyanoacrylate-based, oxalate-aniline-based, malonate-based, and formamidin-based UV absorbers. These can be used alone or in combination of two or more, or in combination with light stabilizers such as hindered amines.

[0038] To allow for diverse design possibilities, the resin composition of this invention may also contain various dyes and pigments without hindering the effectiveness of the invention. Examples include coumarin-based fluorescent dyes, benzopyran-based fluorescent dyes, perylene-based fluorescent dyes, anthraquinone-based fluorescent dyes, thioindigo-based fluorescent dyes, thallium-based fluorescent dyes, thioxanone-based fluorescent dyes, thioxanone-based fluorescent dyes, thiazide-based fluorescent dyes, and diaminostilbene-based fluorescent dyes. The content of the aforementioned dyes and pigments is preferably 0.00001 to 1 part by weight, more preferably 0.00003 to 0.3 parts by weight, based on a total of 100 parts by weight of resin (A), antioxidant (B), and antioxidant (C).

[0039] For methods of obtaining molded articles from resin compositions, known molding and processing techniques can be used, such as injection molding, extrusion molding, sheet molding, compression molding, etc.

[0040] Molded articles obtained by molding the resin composition according to the present invention are particularly suitable for processing into cosmetic containers requiring high design flexibility. Furthermore, the resin composition according to the present invention is suitable for use alone or as a mixed resin blend with other resins such as ABS resin and PC resin.

[0041]

Example

[0042] The following examples illustrate the details, but the present invention is not limited to the following examples.

[0043] <Example of Resin (A-1) Manufacturing>

[0044] The feed liquid supplied to the 50L reactor was prepared as follows: 70 parts by mass of styrene, 15 parts by mass of acrylonitrile, 15 parts by mass of ethylbenzene, 0.02 parts by mass of tert-butylperoxyisopropyl carbonate as a polymerization initiator, and 0.01 parts by mass of n-dodecyl mercaptan as a chain transfer agent. After bubbling with nitrogen, the feed liquid was continuously supplied to the reactor at a rate of 10.8 L / h. At a polymerization temperature of 145°C, an equal volume of reaction liquid was continuously removed while maintaining a reactor filling rate of 70 vol%. The removed reaction liquid was introduced into a volatile component removal device maintained at a high vacuum of 250°C and 10 mmHg to degas and recover unreacted monomers and organic solvents. The copolymer was recovered in granular form.

[0045] <Example of Resin (A-2) Manufacturing>

[0046] The feed liquid supplied to the 50L reactor was prepared as follows: 58 parts by mass of styrene, 22 parts by mass of acrylonitrile, 20 parts by mass of ethylbenzene, 0.02 parts by mass of tert-butylperoxyisopropyl carbonate as a polymerization initiator, and 0.04 parts by mass of n-dodecyl mercaptan as a chain transfer agent. After bubbling with nitrogen, the feed liquid was continuously supplied to the reactor at a rate of 8L / hour. At a polymerization temperature of 145°C, an equal volume of reaction liquid was continuously removed while maintaining a reactor filling rate of 60 vol%. The removed reaction liquid was introduced into a volatile component removal device maintained at a high vacuum of 250°C and 10 mmHg to degas and recover unreacted monomers and organic solvents. The copolymer was recovered in particulate form.

[0047] <Example of Resin (A-3) Manufacturing>

[0048] The feed liquid supplied to the 50L reactor was prepared as follows: 49 parts by mass of styrene, 29 parts by mass of acrylonitrile, 23 parts by mass of ethylbenzene, 0.02 parts by mass of tert-butylperoxyisopropyl carbonate as a polymerization initiator, and 0.12 parts by mass of n-dodecyl mercaptan as a chain transfer agent. After bubbling with nitrogen, the feed liquid was continuously supplied to the reactor at a rate of 9.8 L / h. At a polymerization temperature of 145°C, an equal volume of reaction liquid was continuously removed while maintaining a reactor fill rate of 80 vol%. The removed reaction liquid was then introduced into a volatile component removal device maintained at a high vacuum of 250°C and 10 mmHg to degas and recover unreacted monomers and organic solvents. The copolymer was recovered in particulate form.

[0049] <Example of Resin (A-4) Manufacturing>

[0050] A mixture of 70 parts by weight of styrene, 9 parts by weight of acrylonitrile, 21 parts by weight of ethylbenzene, 0.02 parts by weight of tert-butylperoxyisopropyl carbonate as a polymerization initiator, and 0.12 parts by weight of n-dodecyl mercaptan as a chain transfer agent was prepared. This feed solution was bubbled with nitrogen and continuously fed into the reaction tank at a rate of 9.8 L / h. At a polymerization temperature of 145°C, an equal volume of reaction solution was continuously removed, maintaining a reaction tank filling rate of 75 vol%. The removed reaction solution was introduced into a volatile component removal device maintained at a high vacuum of 250°C and 10 mmHg to degas and recover unreacted monomers and organic solvents. The copolymer was recovered in particulate form.

[0051] <Example of Resin (A-5) Manufacturing>

[0052] The feed liquid supplied to the 50L reactor was prepared as follows: 84 parts by mass of styrene, 16 parts by mass of ethylbenzene, 0.02 parts by mass of tert-butylperoxyisopropyl carbonate as a polymerization initiator, and 0.12 parts by mass of n-dodecyl mercaptan as a chain transfer agent. After bubbling with nitrogen, the feed liquid was continuously supplied to the reactor at a rate of 9.8 L / h. At a polymerization temperature of 145°C, an equal volume of reaction liquid was continuously removed while maintaining a reactor fill rate of 80 vol%. The removed reaction liquid was then introduced into a volatile component removal device maintained at a high vacuum of 250°C and 10 mmHg to degas and recover unreacted monomers and organic solvents. The copolymer was recovered in particulate form.

[0053] The composition of the resin was determined according to JIS K6451-2:2016. The application instructions specify a sample size of 0.2 g, a decomposition temperature of 400 °C, and the use of a standard aqueous solution of sulfuric acid for titration.

[0054] <Antioxidant (B)>

[0055] The following substances are used as antioxidants (B).

[0056] B-1: Pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF JAPAN LTD., Irganox 1010)

[0057] B-2: 4,4',4”-(1-Methylpropionyl-3-ylidene)tris(6-tert-butyl-m-cresol) (ADK STAB AO-30 manufactured by ADEKA Co., Ltd.)

[0058] B-3: 1,3,5,tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene (manufactured by BASF JAPAN LTD., using Irganox 1330)

[0059] B-4: 4,6-Bis(octylthiomethyl)-o-cresol (BASF JAPAN LTD., Irganox 1520)

[0060] B-5: 2,4-bis(octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine (manufactured by BASF JAPAN LTD., Irganox 565)

[0061] B-6: Ethylene bis(oxyvinyl)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate] (manufactured by BASF JAPAN LTD., Irganox 245)

[0062] B-7: Acrylic acid 2-[1-(2-hydroxy-3,5-tert-pentylphenyl)ethyl]-4,6-tert-pentylphenyl (Sumilizer GS, manufactured by Sumitomo Chemical Co., Ltd.)

[0063] B-8: n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate (manufactured by BASF JAPAN LTD., Irganox 1076)

[0064] <Phosphorus-based antioxidants (C)>

[0065] The following substances are used as phosphorus-based antioxidants.

[0066] C-1: Tris(2,4-di-tert-butylphenyl)phosphite (ADK STAB 2112 manufactured by ADEKA Co., Ltd.)

[0067] C-2: Tetra-C12-15-alkyl(propane-2,2-diylbis(4,1-phenylene))bis(phosphite) (ADK STAB 1500 manufactured by ADEKA Co., Ltd.)

[0068] <Resin Composition>

[0069] Examples 1-14, Comparative Examples 1-8

[0070] Resins A-1 to A-5, antioxidant (B), and phosphorus-based antioxidant (C) were mixed according to the proportions shown in Tables 1 to 3, and then extruded and granulated using a uniaxial extruder (MS-40 manufactured by IKG Corporation). Test specimens were made using injection molding machines using these granules, and the physical properties were measured. The results are shown in Tables 1 to 3.

[0071] (Hue and Transmittance)

[0072] Using the obtained particles, a 127×127×3mm thick sheet was formed at a molding temperature of 230°C using an injection molding machine (J140AD-180H, manufactured by Nippon Steel Corporation). 115×85×3mm thick specimens were cut from the sheet, and the end faces were polished to produce sheet-like specimens with mirror-like end faces. The polished sheet-like specimens were then subjected to a UV-Vis spectrophotometer V-670 (manufactured by Nippon Spectrophotometer Co., Ltd.) to measure the spectral transmittance from 350nm to 800nm ​​using incident light with a diameter of 20×1.6mm and a divergence angle of 0°, with a path length of 115mm. The YI value within a 2° field of view of wavelength C light source was calculated according to JIS K7105. Furthermore, transmittance represents the total light transmittance in the range of 430–700nm. The results are shown in Tables 1–3.

[0073] (Chemical resistance)

[0074] To eliminate the influence of molding strain, each particle was pressed into a 4mm thickness at 260℃ and cut into 50mm×50mm square specimens. After immersion in various reagents at 40℃ for 14 days, the specimens were classified according to weight and appearance changes as follows. The reagents used were 5% urea aqueous solution and salad oil.

[0075] ◎: Almost no effect was observed

[0076] ○: Slight turbidity or discoloration was observed.

[0077] △: Minor cracks or fissures have appeared.

[0078] ×: Dissolution or significant impact

[0079] Table 1

[0080]

[0081] Table 2

[0082]

[0083] Table 3

[0084]

[0085] Examples 1-14, which contain a resin (A) comprising a copolymer of aromatic vinyl monomers and cyano monomers, an antioxidant (B) having a total of three or more phenolic sites within the molecule, and a phosphorus-based antioxidant (C), exhibit excellent chemical resistance, transparency, and YI value. Conversely, Comparative Examples 1-5, which use antioxidants having two or fewer phenolic sites within the molecule, Comparative Example 6, which does not use antioxidants, and Comparative Example 7, which does not use phosphorus-based antioxidant (C), exhibit low transmittance, high YI value, and poor color. Comparative Example 8, which uses a resin without cyano monomer components, exhibits excellent transparency and color, but its chemical resistance deteriorates significantly.

[0086] [Industry Applicability]

[0087] The resin composition and molded articles of the present invention exhibit excellent chemical resistance, as well as excellent hue and transparency, making them suitable for applications requiring high design and chemical resistance. Specifically, examples include cosmetic containers, food containers, lighters, and other everyday consumer goods.

Claims

1. A resin composition comprising: a resin (A) containing a copolymer of an aromatic vinyl monomer and a cyano-based monomer, an antioxidant (B) having four or more phenol sites in a molecule in total, and a phosphorus-based antioxidant (C), the resin composition contains no other resin than the resin (A), the resin (A) consists only of a copolymer of an aromatic vinyl monomer and a cyano-based monomer, the copolymer contains 80 to 95 mass% of the aromatic vinyl monomer units when the total of the aromatic vinyl monomer units and the cyano-based monomer units is 100 mass%, the antioxidant (B) is pentaerythritol-tetra[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], the phosphorus-based antioxidant (C) is tris(2,4-di-t-butylphenyl)phosphite, the total content of the antioxidant (B) and the phosphorus-based antioxidant (C) is 0.15 to 0.25 parts by mass with respect to 100 parts by mass of the resin (A), the mass ratio of the antioxidant (B) to the phosphorus-based antioxidant (C) is 5 / 1 to 1 / 2, the aromatic vinyl monomer is styrene.

2. The resin composition according to claim 1, wherein the copolymer of an aromatic vinyl monomer and a cyano-based monomer contains 80 to 95 mass% of the aromatic vinyl monomer units and 5 to 20 mass% of the cyano-based monomer units when the total of the aromatic vinyl monomer and the cyano-based monomer is 100 mass%. molded from the resin composition according to claim 1 or 2. molded from the resin composition according to claim 1 or 2.

3. A shaped body, characterized by ​ 4. A cosmetic container characterized by ​

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