Resin composition, molded body, and cosmetic container

Abstract

The present invention addresses the problem of providing, as a material for cosmetics containers and the like for which especially good design properties are required, a resin that contains: a copolymer of a cyano monomer; and an aromatic vinyl monomer having chemical resistance and having excellent transparency and color tone . The present invention provides a resin composition containing: a resin (A) that includes a copolymer of an aromatic vinyl monomer and a cyano monomer; an antioxidant (B) having a total of three or more phenol moieties within a molecule; and a phosphorous antioxidant (C).

Description

[Technical Field]

[0001] The present invention relates to a resin composition containing a copolymer of an aromatic vinyl monomer and a cyano-based monomer, a molded article thereof, and a cosmetic container. [Background technology]

[0002] Copolymers containing aromatic vinyl monomers and cyano-based monomers have excellent properties such as chemical resistance, rigidity, and moldability, and are therefore used in a wide range of fields. However, thermoplastic copolymers containing cyano-based monomers as one component are prone to color deterioration due to high temperatures during molding. As a result, the actual molded products tend to have a low clarity and appear dull.

[0003] In order to solve such problems, the following methods have been proposed: a method of using an initiator with low hydrogen abstraction ability during polymerization (Patent Document 1); a method of adding an antioxidant having two phenol moieties in the molecule at a polymerization stage where the polymerization rate is 60% or more (Patent Document 2); and a method of using t-amyl peroxy esters containing no aromatic ring when copolymerizing acrylonitrile monomer and styrene-based monomer (Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 4-146908 [Patent Document 2] Japanese Patent Application Publication No. 4-146907 [Patent Document 3] Japanese Patent Application Publication No. 8-301913 Summary of the Invention [Problem to be solved by the invention]

[0005] However, these methods do not sufficiently improve the hue, and it is difficult to say that resins with a satisfactory level of transparency and color tone can be obtained, particularly as raw materials for cosmetic containers, which require high design quality.

[0006] Therefore, an object of the present invention is to provide a resin containing a copolymer of an aromatic vinyl monomer and a cyano-based monomer, which can be used as a raw material for cosmetic containers and the like, which require particularly high design quality, and which can produce molded products that have chemical resistance, high transparency, and high color tone after molding processing. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above problems and have found that the following embodiment is effective. (1) In one embodiment, the resin composition according to the present invention is a resin composition containing: a resin (A) containing a copolymer of an aromatic vinyl monomer and a cyano-based monomer; an antioxidant (B) having a total of three or more phenol moieties in the molecule; and a phosphorus-based antioxidant (C).

[0008] (2) In another embodiment of the resin composition according to the present invention, the total content of the antioxidant (B) and the antioxidant (C) is 0.01 to 0.5 parts by mass relative to 100 parts by mass of the resin (A).

[0009] (3) In another embodiment of the resin composition according to the present invention, the copolymer of an aromatic vinyl monomer and a cyano-based monomer contains 40 to 95 mass% of the aromatic vinyl monomer units and 5 to 60 mass% of the cyano-based monomer units, where the total of the aromatic vinyl monomer and the cyano-based monomer is 100 mass%.

[0010] (4) In another embodiment, the resin composition according to the present invention is a molded article obtained by molding the resin composition according to any one of (1) to (3).

[0011] (5) In another embodiment, the resin composition according to the present invention is a cosmetic container molded from the resin composition according to any one of (1) to (3). [Effects of the Invention]

[0012] According to the present invention, a resin having chemical resistance, high transparency, and excellent color tone is provided. The resin composition can be used for cosmetic containers and the like, which require high design quality. DETAILED DESCRIPTION OF THE INVENTION

[0013] The resin composition of the present invention contains a resin (A) containing a copolymer of an aromatic vinyl monomer and a cyano-based monomer, an antioxidant (B) having a total of three or more phenol moieties in the molecule, and a phosphorus-based antioxidant (C). The resin (A) in the present invention is a resin whose main component is a copolymer of an aromatic vinyl monomer and a cyano-based monomer. The content of the copolymer of an aromatic vinyl monomer and a cyano-based monomer in 100% by mass of the resin (A) is, for example, 50% by mass or more. In one embodiment, the content of the copolymer in the resin (A) is preferably 80% by mass or more, more preferably 80% by mass or more, and even more preferably, the resin (A) consists essentially of the copolymer of an aromatic vinyl monomer and a cyano-based monomer.

[0014] The aromatic vinyl monomer is not particularly limited, but examples thereof include substituted styrenes having a substituent such as styrene, α-methylstyrene, p-methylstyrene, 3,5-dimethylstyrene, 4-methoxystyrene, and 2-hydroxystyrene, halogenated styrenes such as α-bromostyrene and 2,4-dichlorostyrene, and 1-vinylnaphthalene.

[0015] The cyano monomer is not particularly limited, but examples thereof include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, and α-ethylacrylonitrile.

[0016] It is important that the antioxidant (B) of the present invention has a total of three or more phenol moieties in the basic skeleton in the molecule. If there are two or fewer, the antioxidant ability is insufficient, causing deterioration of the resin during molding and worsening of the color.

[0017] Specific examples of the antioxidant (B) that can be used in the present invention include trisphenols 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-methylpropanyl-3-ylidene)tris(6-tert-butyl-m-cresol), and 1,3,5,tris(3,5-di-tert-butyl-4-hydroxyphenylmethyl)-2,4,6-trimethylbenzene, and tetraphenols such as pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], and these may be used alone or in combination of two or more.

[0018] Examples of the phosphorus-based antioxidant (C) of the present invention include trisnonylphenyl phosphite, triphenyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis(2,4-di-t-butylphenyl phosphite), cyclic neopentanetetraylbis(octadecyl phosphite), cyclic neopentanetetraylbis(nonylphenyl phosphite), and tris(mixed, mono- and dinonylphenyl) phosphite. , 4,4'-isopropylidenediphenol alkyl (C12 to C15) phosphite, diphenyl isooctyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, trisisodecyl phosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,2-methylenebis(4,6-di-t-butylphenyl)octyl phosphite, and the like. These may be used alone or in combination of two or more.

[0019] In this embodiment, the total content of the antioxidant (B) and the phosphorus-based antioxidant (C) is preferably 0.01 to 0.50 parts by mass, more preferably 0.05 to 0.40 parts by mass, and even more preferably 0.10 to 0.30 parts by mass, per 100 parts by mass of the resin (A). Specifically, the total content may be, for example, 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 mass, or may be within a range between any two of the values ​​exemplified here. If the total content of the antioxidant (B) and the phosphorus-based antioxidant (C) exceeds 0.50 parts by mass, the heat resistance of the resulting resin composition may be reduced. Furthermore, if the total content of the antioxidant (B) and the phosphorus-based antioxidant (C) is less than 0.01 parts by mass, deterioration in the color of the resulting molded article may not be suppressed.

[0020] The mixing ratio of the antioxidant (B) to the phosphorus-based antioxidant (C) is not particularly limited. The mass ratio of the antioxidant (B) to the phosphorus-based antioxidant (C) is preferably 5 / 1 to 1 / 5, more preferably 4 / 1 to 1 / 4. Specific examples include 5 / 1, 4 / 1, 3 / 1, 2 / 1, 1 / 1, 1 / 2, 1 / 3, 1 / 4, and 1 / 5, and may be within a range between any two of the values ​​exemplified here. By setting the mass ratio of the antioxidant (B) to the phosphorus-based antioxidant (C) to 5 / 1 to 1 / 5, deterioration in the color of the resulting molded article can be efficiently suppressed.

[0021] The method for adding the antioxidant (B) and the phosphorus-based antioxidant (C) is not particularly limited, and examples thereof include a method in which the antioxidant (B) and the phosphorus-based antioxidant (C) are added and mixed in the polymerization step, devolatilization step, or granulation step of the resin (A), and a method in which the antioxidant (B) and the phosphorus-based antioxidant (C) are added and mixed in an extruder or an injection molding machine during molding.

[0022] The proportions of aromatic vinyl monomer and cyano monomer in the resin (A) can be selected arbitrarily, but the amount of aromatic vinyl monomer contained in 100% by mass of the 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, the amount is, for example, 40, 50, 60, 65, 70, 75, 80, 85, 90, or 95% by mass, and may be within a range between any two of the values ​​exemplified here. The amount of cyano monomer contained in 100% by mass of the 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, the amount is, for example, 5, 10, 15, 20, 35, 40, 50, or 60% by mass, and may be within a range between any two of the values ​​exemplified here. If the individual monomers are outside the above composition ranges, it will be difficult to achieve the desired appearance, chemical resistance, transparency, mechanical properties, etc. of the molded article that are the objectives of the present invention.

[0023] The resin (A) containing a copolymer of an aromatic vinyl monomer and a cyano-based monomer in the present invention can be produced by a suspension polymerization method, a solution polymerization method, a bulk polymerization method, or the like. However, in order to prevent the inclusion of dispersants and the like in the resin, the solution polymerization method or the bulk polymerization method is preferably used.

[0024] Resin (A) may be copolymerized with copolymerizable monomers other than cyano-based monomers and aromatic vinyl monomers to the extent that the effects of the present invention are not impaired. Examples of other vinyl compounds copolymerizable with cyano-based monomers and aromatic vinyl monomers include acrylic acid esters such as methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate; unsaturated carboxylic acids or anhydrides thereof such as acrylic acid, methacrylic acid, maleic anhydride, and itaconic acid; and maleimide compounds such as N-phenylmaleimide and N-cyclohexylmaleimide. Ethyl acrylate and butyl acrylate are particularly preferred, and two or more of these can also be used in combination. The content of these monomers is 0 to 20% by weight, preferably 0 to 10% by weight, when the total of the cyano monomer, aromatic vinyl monomer, and monomers copolymerizable therewith is 100% by mass.

[0025] In producing the resin (A), a molecular weight modifier such as t-dodecyl mercaptan, n-dodecyl mercaptan, an unsaturated dimer of α-methylstyrene, terpinolene, or octyl thioglycolate may be used.

[0026] The resin composition of the present invention may contain mineral oil to the extent that the effects of the present invention are not impaired.The resin composition of the present invention may also contain additives such as internal lubricants such as stearic acid and ethylene bisstearylamide, sulfur-based antioxidants, lactone-based antioxidants, ultraviolet absorbers, hindered amine-based stabilizers, antistatic agents, and external lubricants.

[0027] The ultraviolet absorber has the function of suppressing deterioration and coloration due to ultraviolet rays, and examples thereof include ultraviolet absorbers based on benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, anilide oxalates, malonic acid esters, formamidines, etc. These may be used alone or in combination of two or more, and may also be used in combination with a light stabilizer such as a hindered amine.

[0028] The resin composition of the present invention may contain various dyes and pigments to achieve diverse design possibilities, provided that the effects of the present invention are not impaired. Examples include coumarin-based fluorescent dyes, benzopyran-based fluorescent dyes, perylene-based fluorescent dyes, anthraquinone-based fluorescent dyes, thioindigo-based fluorescent dyes, xanthene-based fluorescent dyes, xanthone-based fluorescent dyes, thioxanthene-based fluorescent dyes, thioxanthone-based fluorescent dyes, thiazine-based fluorescent dyes, and diaminostilbene-based fluorescent dyes. The content of the dyes and pigments is preferably 0.00001 to 1 part by mass, more preferably 0.00003 to 0.3 parts by mass, based on 100 parts by mass of the total of the resin (A), antioxidant (B), and antioxidant (C).

[0029] As a method for obtaining a molded article from the resin composition, known molding techniques can be used, such as injection molding, extrusion molding, sheet molding, and press molding.

[0030] The molded article obtained by molding the resin composition of the present invention can be processed into a cosmetic container, which requires particularly high design quality. The resin composition of the present invention is also suitable for use alone or as a mixed resin blended with other resins such as ABS resin or PC resin. [Example]

[0031] The following detailed description will be given using examples, but the present invention is not limited to the following examples. Examples 2, 3, 5 and 6 are reference examples.

[0032] <Production example of resin (A-1)> The feed solution to be supplied to a 50 L reactor was prepared to consist of 70 parts by mass of styrene, 15 parts by mass of acrylonitrile, 15 parts by mass of ethylbenzene, 0.02 parts by mass of t-butylperoxyisopropyl carbonate as a polymerization initiator, and 0.01 parts by mass of n-dodecyl mercaptan as a chain transfer agent. After bubbling this feed solution with nitrogen gas, it was continuously fed to the reactor at a rate of 10.8 L / h, maintaining the polymerization temperature at 145 °C and the reaction solution filling rate in the reactor at 70 vol%, while continuously withdrawing an amount of reaction solution equal to the amount of feed solution. The withdrawn reaction solution was introduced into a devolatilizer maintained at 250 °C and a high vacuum of 10 mmHg, where unreacted monomer and organic solvent were degassed and recovered, and the copolymer was recovered as pellets.

[0033] <Production example of resin (A-2)> The feed solution to be supplied to a 50 L 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 t-butylperoxyisopropyl carbonate as a polymerization initiator, and 0.04 parts by mass of n-dodecyl mercaptan as a chain transfer agent. After bubbling this feed solution with nitrogen gas, it was continuously fed to the reactor at a rate of 8 L / h. The polymerization temperature was maintained at 145 °C, and the reaction solution filling rate in the reactor was maintained at 60 vol%, and an amount of reaction solution equal to the amount of feed solution was continuously withdrawn. The withdrawn reaction solution was introduced into a devolatilizer maintained at 250 °C and a high vacuum of 10 mmHg. Unreacted monomer and organic solvent were degassed and recovered, and the copolymer was recovered as pellets.

[0034] <Production example of resin (A-3)> The feed solution to be supplied to a 50 L reactor was prepared to consist of 49 parts by mass of styrene, 29 parts by mass of acrylonitrile, 23 parts by mass of ethylbenzene, 0.02 parts by mass of t-butylperoxyisopropyl carbonate as a polymerization initiator, and 0.12 parts by mass of n-dodecyl mercaptan as a chain transfer agent. After bubbling this feed solution with nitrogen gas, it was continuously fed to the reactor at a rate of 9.8 L / h, maintaining a polymerization temperature of 145 °C and a reaction solution filling rate of 80 vol% in the reactor. An amount of reaction solution equal to the amount of feed solution was continuously withdrawn. The withdrawn reaction solution was introduced into a devolatilizer maintained at 250 °C and a high vacuum of 10 mmHg, where unreacted monomer and organic solvent were degassed and recovered, and the copolymer was recovered as pellets.

[0035] <Production example of resin (A-4)> The mixture consisted of 70 parts by mass of styrene, 9 parts by mass of acrylonitrile, 21 parts by mass of ethylbenzene, 0.02 parts by mass of t-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 gas, this feed solution was continuously fed to the reactor at a rate of 9.8 L / h. The polymerization temperature was maintained at 145 °C, and the reaction solution filling rate in the reactor was maintained at 75 vol%. An amount of reaction solution equal to the amount of feed solution was continuously withdrawn. The withdrawn reaction solution was introduced into a devolatilizer maintained at 250 °C and a high vacuum of 10 mmHg. Unreacted monomer and organic solvent were degassed and recovered, and the copolymer was recovered as pellets.

[0036] <Production example of resin (A-5)> The feed solution to be supplied to a 50 L reactor was prepared to consist of 84 parts by mass of styrene, 16 parts by mass of ethylbenzene, 0.02 parts by mass of t-butylperoxyisopropyl carbonate as a polymerization initiator, and 0.12 parts by mass of n-dodecyl mercaptan as a chain transfer agent. After bubbling this feed solution with nitrogen gas, it was continuously fed to the reactor at a rate of 9.8 L / h, maintaining a polymerization temperature of 145 °C and a reaction solution filling rate of 80 vol% in the reactor. An amount of reaction solution equal to the amount of feed solution was continuously withdrawn. The withdrawn reaction solution was introduced into a devolatilizer maintained at 250 °C and a high vacuum of 10 mmHg. Unreacted monomer and organic solvent were degassed and recovered, and the copolymer was recovered as pellets.

[0037] The composition analysis of the resin was performed in accordance with JIS K6451-2: 2016. The sample size was 0.2 g, the decomposition temperature was 400°C, and the titration standard solution was a standard aqueous solution of sulfuric acid.

[0038] <Antioxidant (B)> As the antioxidant (B), the following was used. B-1: Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010, manufactured by BASF Japan Ltd.) B-2: 4,4',4''-(1-methylpropanyl-3-ylidene)tris(6-tert-butyl-m-cresol) (ADEKA Corporation, ADK STAB AO-30) B-3: 1,3,5, tris(3,5-di-tert-butyl-4-hydroxyphenylmethyl)-2,4,6-trimethylbenzene (Irganox 1330, manufactured by BASF Japan Ltd.) B-4: 4,6-bis(octylthiomethyl)-o-cresol (Irganox 1520, manufactured by BASF Japan Ltd.) B-5: 2,4-bis(octylthio)-6-(4-hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine (Irganox 565, manufactured by BASF Japan Ltd.) B-6: Ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxybenzoate] (m-tolyl) propionate (Irganox 245, manufactured by BASF Japan Ltd.) B-7: 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate (Sumilizer GS, manufactured by Sumitomo Chemical Co., Ltd.) B-8: n-Octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate (Irganox 1076, manufactured by BASF Japan Ltd.)

[0039] <Phosphorus-based antioxidant (C)> The following phosphorus-based antioxidants were used: C-1: Tris(2,4-di-tert-butylphenyl) phosphite (ADEKA Corporation, ADK STAB 2112) C-2: Tetra-C12-15-alkyl(propane-2,2-diylbis(4,1-phenylene))bis(phosphite) (ADEKA Corporation, ADK STAB 1500)

[0040] <Resin composition> Examples 1 to 14, Comparative Examples 1 to 8 Resins A-1 to A-5 were blended with antioxidant (B) and phosphorus-based antioxidant (C) in the proportions shown in Tables 1 to 3, and then extruded and pelletized using a single-screw extruder (MS-40, manufactured by IKG Corporation). Test pieces were prepared using these pellets in an injection molding machine, and various physical properties were measured. The results are shown in Tables 1 to 3.

[0041] (Hue / Transmittance) The pellets were then molded into plates measuring 127 × 127 × 3 mm at a molding temperature of 230°C using an injection molding machine (J140AD-180H, manufactured by Nippon Steel Corporation). Test pieces measuring 115 × 85 × 3 mm were cut from the plates, and the edges were polished by buffing to create plates with mirror-finished edges. The polished plates were measured for spectral transmittance from 350 nm to 800 nm using a JASCO V-670 UV-Visible Spectrophotometer with dimensions of 20 × 1.6 mm and an incident light beam with a divergence angle of 0°, over a 115 mm optical path length, using a wavelength C light source. The YI value was calculated according to JIS K7105 at a 2° field of view. The transmittance indicates the total light transmittance in the range of 430 to 700 nm. The results are shown in Tables 1 to 3.

[0042] (chemical resistance) To eliminate the effects of molding distortion, test specimens were prepared by press-molding each pellet at 260°C to a thickness of 4 mm and then cutting into 50mm x 50mm squares. After immersion in each chemical set at 40°C for 14 days, the specimens were classified as follows based on changes in weight and appearance. The chemicals used were a 5% urea solution and salad oil. ◎: Almost no effect observed, ○: Slight cloudiness or discoloration observed, △: Slight cracking or crazing occurred, ×: Dissolution or significant effect observed

[0043] [Table 1]

[0044] [Table 2]

[0045] [Table 3]

[0046] Examples 1 to 14, which contained a resin (A) allegedly containing a copolymer of an aromatic vinyl monomer and a cyano-based monomer, an antioxidant (B) having a total of three or more phenolic moieties in the molecule, and a phosphorus-based antioxidant (C), had excellent chemical resistance and excellent transparency and YI values. On the other hand, Comparative Examples 1 to 5, which used an antioxidant with two or fewer phenolic moieties in the molecule, Comparative Example 6, which used no antioxidant, and Comparative Example 7, which did not use a phosphorus-based antioxidant (C), exhibited low transmittance, high YI values, and poor hue. Comparative Example 8, which used a resin containing no cyano-based monomer component, exhibited excellent transparency and hue, but significantly deteriorated chemical resistance. [Industrial Applicability]

[0047] The resin composition and molded article of the present invention have excellent chemical resistance, color, and transparency, and therefore can be suitably used in applications requiring high designability and chemical resistance, such as cosmetic containers, food containers, and miscellaneous goods such as lighters.

Claims

1. A resin composition comprising: The present invention comprises a resin (A) consisting solely of a copolymer of an aromatic vinyl monomer and a cyano-based monomer, an antioxidant (B) having a total of four or more phenol moieties in the molecule, and a phosphorus-based antioxidant (C), the copolymer is a polymer obtained by copolymerizing only the aromatic vinyl monomer and the cyano-based monomer, the copolymer contains 80% by mass or more of the aromatic vinyl monomer units, when the total of the aromatic vinyl monomer units derived from the aromatic vinyl monomer and the cyano monomer units derived from the cyano monomer is taken as 100% by mass; the aromatic vinyl monomer is styrene, A resin composition, wherein the resin (A) accounts for 99.7% by mass or more of 100% by mass of the resin composition.

2. 2. The resin composition according to claim 1, wherein the total content of the antioxidant (B) and the antioxidant (C) is 0.01 to 0.30 parts by mass per 100 parts by mass of the resin (A).

3. 3. The resin composition according to claim 1, wherein the copolymer contains 80 to 95 mass% of the aromatic vinyl monomer units and 5 to 20 mass% of the cyano-based monomer units, where the total of the aromatic vinyl monomer units and the cyano-based monomer units is 100 mass%.

4. A molded article obtained by molding the resin composition according to any one of claims 1 to 3.

5. A cosmetic container formed from the resin composition according to any one of claims 1 to 3.

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