JP2023002908A - Resin composition and molded body - Google Patents

Abstract

To provide a composition containing a polycarbonate resin, excellent in surface hardness, which can provide moldability with excellent chemical resistance to cosmetics, hand creams, etc.SOLUTION: A resin composition contains: a polycarbonate resin (A); a polymer (B) containing a (meth)acrylate unit, and having a glass transition temperature of 50°C or higher; and a graft copolymer (C) in which a polymer component containing a polymer having at least a glass transition temperature of -30°C or lower is polymerized with a (meth)acrylic acid aromatic ester monomer.SELECTED DRAWING: None

Description

The present invention relates to resin compositions and molded articles.

Aromatic polycarbonate resin is excellent in transparency, heat resistance, etc., and the molded products obtained are excellent in dimensional stability. It is widely used as a raw material resin for manufacturing precision molded products such as parts. In particular, in housings for home electric appliances, electronic devices, image display devices, etc., products with high commercial value can be obtained by taking advantage of their beautiful appearance.

However, the aromatic polycarbonate resin has a problem of low surface hardness and being easily scratched. In order to solve this problem, there is a method of improving the surface hardness by adding a specific (meth)acrylate copolymer. On the other hand, when a (meth)acrylate copolymer is added to an aromatic polycarbonate resin, the impact resistance of the resulting molded article may be lowered. Therefore, it is known to mix a specific graft copolymer in order to prevent a decrease in impact resistance (Public Document 1).

International Publication No. 2013/11804

However, according to the studies of the present inventors, when a molded article produced by adding a graft copolymer to an aromatic polycarbonate resin as in Publicly Known Document 1 is used in applications where there are many opportunities to come into contact with human hands, It was found that the molded article has low chemical resistance to cosmetics and hand creams, and cracks may occur.
Accordingly, an object of the present invention is to provide a resin composition for obtaining a molded article having excellent surface hardness and excellent chemical resistance to cosmetics, hand creams, and the like.

As a result of intensive studies to solve the above problems, the present inventors have found that by blending a specific polymer and a graft copolymer into a polycarbonate resin, the surface hardness is excellent, and it is excellent for cosmetics, hand creams, etc. It has been found that it is possible to provide moldability with excellent chemical resistance. That is, the present invention has been achieved based on such findings, and the gist thereof is as follows.

[1] Polycarbonate resin (A), a polymer (B) containing (meth)acrylate units and having a glass transition temperature of 50°C or higher, and a polymer having at least a glass transition temperature of -30°C or lower A resin composition containing, as a combined component, a graft copolymer (C) in which a (meth)acrylic acid aromatic ester monomer is polymerized.
[2] The resin composition according to [1], wherein the proportion of the polycarbonate resin (A) in 100 parts by mass of the resin composition is 70 parts by mass or more and 90 parts by mass or less.
[3] The resin composition according to [1] or [2], wherein the proportion of the polymer (B) in 100 parts by mass of the resin composition is 10 parts by mass or more and 30 parts by mass or less.
[4] The resin composition according to any one of [1] to [3], wherein the proportion of the graft copolymer (C) in 100 parts by mass of the resin composition is 3 parts by mass or more and 30 parts by mass or less.
[5] The resin composition according to any one of [1] to [4], wherein the proportion of (meth)acrylate in 100 parts by mass of the polymer (B) is 50 parts by mass or more.
[6] The resin composition according to any one of [1] to [5], wherein the polymer (B) has a mass average molecular weight of 5000 or more and 30000 or less.
[7] The proportion of the polymer component in 100 parts by mass of the graft copolymer (C) is 40 parts by mass or more and 90 parts by mass or less, and the glass transition temperature in 100 parts by mass of the polymer component is -30°C. The resin composition according to any one of [1] to [6], wherein the proportion of the polymer below is 10 parts by mass or more and 55 parts by mass or less.
[8] In 100 parts by mass of the graft copolymer (C), the ratio of the (meth)acrylic acid aromatic ester unit polymerized to the polymer component containing the polymer having at least the glass transition temperature of −30° C. or lower is , 1 part by mass or more and 20 parts by mass or less, the resin composition according to any one of [1] to [7].
[9] A molded article obtained by molding the resin composition according to any one of [1] to [8].

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a resin composition for obtaining a molded article having excellent surface hardness and excellent chemical resistance to cosmetics, hand creams, and the like.

Hereinafter, the present invention will be described in detail by showing embodiments and examples, etc., but the present invention is not limited to the embodiments, examples, etc. shown below, and can be arbitrarily used without departing from the scope of the present invention. can be implemented by changing to

In the present invention, "(meth)acrylate" means one or both of "acrylate" and "methacrylate". In addition, the “unit” means a structural portion derived from a raw material monomer used when copolymerizing monomers to produce a (meth)acrylate copolymer.

The resin composition according to the present embodiment comprises a polycarbonate resin (A), a polymer (B) containing a (meth)acrylate unit and having a glass transition temperature of 50°C or higher, and at least a glass transition temperature of -30°C. A graft copolymer (C) obtained by polymerizing a (meth)acrylic acid aromatic ester monomer is included in the polymer component including the following polymer.

When the resin composition has the above structure, it is possible to provide a molded article having high surface hardness and high chemical resistance to cosmetics, hand creams, and the like. Although the reason for this is not clear, the following reasons are conceivable.

By blending the polymer (B) having a Tg of −50° C. or less with the aromatic polycarbonate resin, the surface hardness of the obtained molded article is improved, but the mechanical strength tends to be lowered. Furthermore, a decrease in mechanical strength makes chemical cracks more likely to occur due to stress and contact with chemicals, resulting in a decrease in chemical resistance. Therefore, in the present invention, the graft copolymer (C) is further blended, and the presence of a polymer component having a Tg of −30° C. or less in the graft copolymer (C) suppresses deterioration of mechanical properties. At the same time, the presence of the aromatic (meth)acrylate contained as a graft component of the graft copolymer (C) suppresses the penetration of mineral oil, petrolatum, etc. contained in cosmetics and hand creams, and alleviates the load of chemical contact. As a result, it is thought that the chemical resistance can be improved.

[Aromatic polycarbonate resin (A)]
The aromatic polycarbonate resin (A) is an optionally branched thermoplastic polymer or copolymer obtained by reacting an aromatic dihydroxy compound or a small amount of a polyhydroxy compound with phosgene or a carbonic acid diester. be. The method for producing the aromatic polycarbonate resin is not particularly limited, and one produced by a conventionally known phosgene method (interfacial polymerization method) or melting method (ester exchange method) can be used. Moreover, when the melting method is used, an aromatic polycarbonate resin in which the amount of OH groups in terminal groups is adjusted can be used.

Raw aromatic dihydroxy compounds include 2,2-bis(4-hydroxyphenyl)propane (=bisphenol A), tetramethylbisphenol A, bis(4-hydroxyphenyl)-p-diisopropylbenzene, hydroquinone, resorcinol, 4 ,4-dihydroxydiphenyl and the like, preferably bisphenol A. A compound in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compound can also be used.

To obtain a branched aromatic polycarbonate resin, a portion of the aromatic dihydroxy compound described above is combined with the following branching agents: phloroglucine, 4,6-dimethyl-2,4,6-tri(4-hydroxyphenyl) heptene-2,4,6-dimethyl-2,4,6-tri(4-hydroxyphenyl)heptane, 2,6-dimethyl-2,4,6-tri(4-hydroxyphenylheptene-3,1, 3,5-tri(4-hydroxyphenyl)benzene, 1,1,1-tri(4-hydroxyphenyl)ethane and other polyhydroxy compounds, and 3,3-bis(4-hydroxyaryl)oxindole (= isa tinbisphenol), 5-chlorisatin, 5,7-dichlorisatin, 5-bromysatin, etc. The amount of these substituting compounds to be used is usually 0.01 to 10 mol relative to the aromatic dihydroxy compound. %, preferably 0.1 to 2 mol %.

Among the aromatic polycarbonate resins (A) mentioned above, polycarbonate resins derived from 2,2-bis(4-hydroxyphenyl)propane, or 2,2-bis(4-hydroxyphenyl)propane and other A polycarbonate copolymer derived from an aromatic dihydroxy compound is preferred. It may also be a copolymer mainly composed of a polycarbonate resin, such as a copolymer with a polymer or oligomer having a siloxane structure. In addition, aromatic polycarbonate resin may be used individually by 1 type, and may be used in mixture of 2 or more types.

A monovalent aromatic hydroxy compound may be used to adjust the molecular weight of the aromatic polycarbonate resin. Examples of the monovalent aromatic hydroxy compound include m- and p-methylphenol, m- and p- Propylphenol, p-tert-butylphenol, p-long-chain alkyl-substituted phenol and the like can be mentioned.

The molecular weight of the aromatic polycarbonate resin (A) is arbitrary depending on the application, and may be appropriately selected and determined. The weight average molecular weight (Mw) in terms of polycarbonate (PC) measured by is preferably 15,000 or more, more preferably 17,000 or more, still more preferably 19,000 or more, while preferably 40,000 or less, 30,000 Below is more preferred, and 27,000 or less is even more preferred.

Thus, by setting the mass average molecular weight to 15,000 or more, the mechanical strength tends to be further improved, which is more preferable when used in applications requiring high mechanical strength. On the other hand, when the mass average molecular weight is 40,000 or less, the decrease in fluidity tends to be suppressed and improved, which is more preferable from the viewpoint of easy molding processability.

Also, two or more aromatic polycarbonate resins having different weight average molecular weights may be mixed. In this case, the weight average molecular weight of the mixture of two or more aromatic polycarbonate resins is preferably within the above range.

[Polymer (B)]
Polymer (B) is a polymer having at least one (meth)acrylate unit and having a glass transition temperature of 50° C. or higher. By containing the polymer (B) in the resin composition, the surface hardness of the molded article obtained using the resin composition according to the present embodiment can be improved. In the present invention, for the glass transition temperature of the polymer, the literature value described in POLYMER HANDBOOK FOURTH EDITION Volume 1 (1999, John Wiley & Sons, Inc.) can be used. can be measured based on dynamic mechanical properties (JIS K7244: 1998).

The polymer (B) is not particularly limited, and can be in the form of random copolymers, block copolymers, etc. Among them, random copolymers are preferred.

The (meth)acrylate is not particularly limited, but preferably includes an aliphatic (meth)acrylic acid ester and an aromatic (meth)acrylic acid ester.

The (meth)aliphatic acrylic acid ester is not particularly limited, but it is preferable that the alkyl group of the aliphatic ester has 1 or more carbon atoms, while the alkyl group of the aliphatic ester has 10 or less carbon atoms. The number of carbon atoms in the alkyl group of the aliphatic ester is preferably 8 or less, and more preferably 5 or less. Examples of such (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, propyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Among them, methyl (meth)acrylate is most preferred.

The (meth)acrylic acid aromatic ester is not particularly limited, but is preferably a (meth)acrylate having a phenyl group which may have an alkyl group. In this case, the number of carbon atoms in the alkyl group is preferably 1 or more, while the number of carbon atoms in the alkyl group is preferably 10 or less, and more preferably 8 or less. More preferably, the group has 5 or less carbon atoms. In addition, the phenyl group may have a plurality of alkyl groups. Examples of (meth)acrylic acid aromatic esters having a phenyl group optionally having an alkyl group include phenyl (meth)acrylate, benzyl (meth)acrylate, naphthyl (meth)acrylate, p-diphenyl (meth)acrylate, o-diphenyl (meth)acrylate, o-chlorodiphenyl (meth)acrylate, 4-methoxyphenyl (meth)acrylate, 4-chlorophenyl (meth)acrylate, 2,4,6-trichlorophenyl (meth)acrylate Acrylate, 4-tertbutylphenyl (meth)acrylate and the like can be mentioned.

(Meth)acrylates may be used alone or in combination of two or more. Among these, methyl (meth)acrylate, phenyl methacrylate and benzyl methacrylate are preferred, and methyl (meth)acrylate and phenyl methacrylate are more preferred.

Polymer (B) may contain vinyl monomer units other than (meth)acrylate units. Other vinyl monomers are not particularly limited, but include aromatic vinyl monomers other than the above-mentioned (meth)acrylic acid aromatic esters.

Other aromatic vinyl monomer units include styrene, α-methylstyrene, p-methylstyrene, pt-butylstyrene, p-methoxystyrene, o-methoxystyrene, 2,4-dimethylstyrene and chlorostyrene. , bromostyrene, vinyltoluene, vinylnaphthalene, vinylanthracene, and the like.

The proportion of (meth)acrylate in 100 parts by mass of the polymer (B) is preferably 50 parts by mass or more, preferably 70 parts by mass or more for further improvement of surface hardness, and 80 parts by mass. It is more preferably 90 parts by mass or more, and the upper limit is 100 parts by mass.

Among the above, the ratio of the (meth)acrylic acid aliphatic ester to 100 parts by mass of the polymer (B) is preferably 50 parts by mass or more, more preferably 60 parts by mass or more.

Further, the proportion of the (meth)acrylic acid aromatic ester in 100 parts by mass of the polymer (B) is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, while 50 parts by mass parts by mass or less, and more preferably 40 parts by mass or less.

The ratio of other vinyl monomer units in 100 parts by mass of the polymer (B) is not particularly limited, but is preferably 30 parts by mass or less, more preferably 20 parts by mass or less. It is more preferably 10 parts by mass or less, while the lower limit is 0 parts by mass.

The mass average molecular weight of the polymer (B) is not particularly limited, but is preferably 5,000 or more, more preferably 6,000 or more, and further preferably 7,000 or more. On the other hand, it is preferably 30,000 or less, more preferably 25,000 or less, even more preferably 20,000 or less.

Within the range in which the weight average molecular weight of the polymer (B) is defined above, the compatibility with the aromatic polycarbonate resin (A) becomes better, and the effect of further improving the surface hardness is excellent.
In the present invention, the mass average molecular weight (Mw) can be measured using gel permeation chromatography using chloroform or tetrahydrofuran (THF) as a solvent. In addition, the molecular weight is a value in terms of polystyrene (PS).

As described above, the glass transition temperature of the polymer (B) is 50° C. or higher, preferably 60° C. or higher, more preferably 70° C. or higher, in order to improve heat resistance. The temperature is preferably 150° C. or lower, more preferably 140° C. or lower, in order to improve workability.

As a method for polymerizing the monomers for obtaining the (meth)acrylate copolymer (B), known methods such as emulsion polymerization, suspension polymerization, solution polymerization and bulk polymerization can be used. . A suspension polymerization method or a bulk polymerization method is preferable, and a suspension polymerization method is more preferable. Additives necessary for polymerization can be added as needed, and examples of additives include polymerization initiators, emulsifiers, dispersants, chain transfer agents, and the like.

[Graft copolymer (C)]
The graft copolymer (C) comprises a polymer portion (d) containing a polymer having a glass transition temperature of −30° C. or lower, and a polymer portion (e) containing a (meth)acrylic acid aromatic ester unit as a graft component. )including. More specifically, it is a graft copolymer in which a monomer component containing at least a (meth)acrylic acid aromatic ester is polymerized to a polymer component containing a polymer having a glass transition temperature of −30° C. or less. .

Polymers having a glass transition temperature of −30° C. or lower are not particularly limited, but include polymers containing butadiene units and polymers containing organosiloxane units. In addition, you may use individually by 1 type and may use 2 or more types together.

Among the above, the polymer having a glass transition temperature of −30° C. or less is preferably a polymer having a glass transition temperature of −40° C. or less, and a polymer having a glass transition temperature of −50° C. or less. On the other hand, it is preferably a polymer having a glass transition temperature of −120° C. or higher, more preferably a polymer having a glass transition temperature of −110° C. or higher, and a glass transition temperature of −100° C. or higher. is more preferably a polymer of

The polymer portion (d) may be a composite polymer containing other polymers in addition to the -30° C. or lower polymer. For example, it may be a composite polymer containing a polymer with a glass transition temperature exceeding -30°C.

Polymers having a glass transition temperature exceeding −30° C. are not particularly limited, but monomer components include aromatic vinyl monomers such as styrene and α-methylstyrene; methyl (meth)acrylate, ethyl ( Alkyl (meth)acrylate monomers such as meth)acrylate and n-butyl (meth)acrylate; Vinyl cyanide monomers such as (meth)acrylonitrile; Alkyl vinyl ether monomers such as methyl vinyl ether and butyl vinyl ether; Vinyl chloride , vinyl halide monomers such as vinyl bromide; vinylidene chloride monomers such as vinylidene chloride and vinylidene bromide; polymers such as glycidyl group-containing vinyl monomers such as glycidyl (meth)acrylate and allyl glycidyl ether are mentioned. In addition, these monomers may be used individually by 1 type, and may use 2 or more types together.

Furthermore, a crosslinkable monomer may be included for producing these polymers.

Examples of crosslinkable monomers include aromatic polyfunctional vinyl monomers such as divinylbenzene and divinyltoluene; polyhydric alcohols such as ethylene glycol di(meth)acrylate and 1,3-butanediol di(meth)acrylate. di- or tri-(meth)acrylate monomers; allyl (meth)acrylate monomers; di- or triallyl monomers such as diallyl phthalate and triallyltriazine.
The crosslinkable monomers may be used singly or in combination of two or more.

In the case of a composite polymer in which the polymer portion (d) is composed of two or more polymers, a polymer having a glass transition temperature of −30° C. or lower in 100 parts by mass of the polymer component for producing the composite polymer. Although there is no particular limitation on the ratio of On the other hand, in order to improve the appearance, the amount is preferably 55 parts by mass or less, more preferably 50 parts by mass or less, and particularly preferably 45 parts by mass or less.

In this case, the proportion of the polymer component having a glass transition temperature exceeding −30° C. in 100 parts by mass of the polymer component is not particularly limited, but is preferably 40 parts by mass or more in order to improve the appearance. , it is more preferably 45 parts by mass or more, particularly preferably 50 parts by mass or more. On the other hand, in order to improve impact resistance, it is preferably 65 parts by mass or less, and 60 parts by mass or less. is more preferable, and 55 parts by mass or less is particularly preferable.

In this case, the proportion of the crosslinkable monomer in 100 parts by mass of the polymer component is not particularly limited, but in order to improve impact resistance, it is preferably 10 parts by mass or more, and 15 parts by mass or more. It is more preferably 20 parts by mass or more, and on the other hand, for improving the appearance, it is preferably 55 parts by mass or less, more preferably 50 parts by mass or less, and 45 parts by mass. The following are particularly preferred.

The ratio of the polymer portion (d) in 100 parts by mass of the graft copolymer (C) is not particularly limited, but is preferably 40 parts by mass or more, and 50 parts by mass or more, in order to improve chemical resistance. It is more preferably 60 parts by mass or more, and on the other hand, in order to improve the appearance of the molded product, it is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, and 70 parts by mass. Part or less is more preferable.

As described above, the graft copolymer (C) has at least (meth)acrylic acid aromatic ester units as the graft component (e).

(Meth)acrylic acid aromatic esters are not particularly limited, but preferably include (meth)acrylates having a phenyl group which may have an alkyl group. In this case, the number of carbon atoms in the alkyl group is preferably 1 or more, while the number of carbon atoms in the alkyl group is preferably 20 or less, and more preferably 15 or less. More preferably, the group has 10 or less carbon atoms. In addition, the phenyl group may have a plurality of alkyl groups. Examples of (meth)acrylic acid aromatic alkyl esters having a phenyl group optionally having an alkyl group include phenyl (meth)acrylate, benzyl (meth)acrylate, naphthyl (meth)acrylate, p- Diphenyl (meth)acrylate, o-diphenyl (meth)acrylate, o-chlorodiphenyl (meth)acrylate, 4-methoxyphenyl (meth)acrylate, 4-chlorophenyl (meth)acrylate, 2,4,6-trichlorophenyl (meth)acrylate ) acrylate, 4-tertbutylphenyl (meth)acrylate, and the like.

Graft component (e) may also have other vinyl monomer units. Other vinyl monomers are not particularly limited, and include vinyl aromatic esters other than (meth)acrylic acid fatty acid esters and (meth)acrylic acid aromatic esters.

The (meth)acrylic fatty acid ester is not particularly limited, and it is preferable that the alkyl group of the fatty acid ester has 1 or more carbon atoms, while the alkyl group of the aliphatic ester has 10 or less carbon atoms. is preferred, the number of carbon atoms in the alkyl group of the aliphatic ester is preferably 8 or less, and the number of carbon atoms in the alkyl group of the aliphatic ester is further preferably 5 or less. Examples of such (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, propyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Among them, methyl (meth)acrylate is most preferred.

The number of carbon atoms in the alkyl group of the aromatic ester other than the (meth)acrylic acid aromatic ester is not particularly limited, but is preferably 1 or more, preferably 20 or less, and 15 or less. is more preferable, and 10 or less is even more preferable. Vinyl aromatic esters other than such (meth)acrylic acid aromatic esters include, for example, styrene, α-methylstyrene, p-methylstyrene, pt-butylstyrene, p-methoxystyrene, o- Methoxystyrene, 2,4-dimethylstyrene, chlorostyrene, bromostyrene, vinyltoluene, vinylnaphthalene, vinylanthracene. Among them, styrene is most preferred.

The ratio of the graft component (e) in 100 parts by mass of the graft copolymer (C) is not particularly limited, but is preferably 6 parts by mass or more, more preferably 7 parts by mass or more, in order to improve the transmittance. is more preferably 8 parts by mass or more. On the other hand, for chemical resistance, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and 30 parts by mass or less. It is even more preferable to have

The ratio of the (meth)acrylic acid aromatic ester unit of the graft component (e) in 100 parts by mass of the graft copolymer (C) is not particularly limited, but in order to further improve chemical resistance, 1 part by mass It is preferably at least 2 parts by mass, more preferably at least 2 parts by mass, and even more preferably at least 3 parts by mass. It is more preferably 10 parts by mass or less, more preferably 10 parts by mass or less.

The ratio of the (meth)acrylic fatty acid ester unit of the graft component (e) in 100 parts by mass of the graft copolymer (C) is not particularly limited, but is preferably 10 parts by mass or less for the appearance of the molded product. , more preferably 9 parts by mass or less, more preferably 8 parts by mass or less, and the lower limit thereof is 0 parts by mass.

The ratio of the vinyl aromatic ester units other than the (meth)acrylic acid aromatic ester of the graft component (e) in 100 parts by mass of the graft copolymer (C) is not particularly limited. It is preferably 5 parts by mass or more, more preferably 7.5 parts by mass or more, and still more preferably 10 parts by mass or more. On the other hand, for chemical resistance, it should be 29 parts by mass or less. is preferred, 25 parts by mass or less is more preferred, and 20 parts by mass or less is even more preferred.

Although the mass average particle size of the graft copolymer (C) is not particularly limited, it is preferably 0.05 μm or more, more preferably 0.06 μm or more, and still more preferably 0.08 μm for chemical resistance. For product appearance, it is preferably 0.3 μm or less, more preferably 0.2 μm or less, and even more preferably 0.15 μm or less.

The method for producing the polymer portion (d) is not particularly limited, and may be polymerized by a known method. For example, a monomer constituting a polymer having a glass transition temperature of −30° C. or less and optionally a crosslinkable monomer may be added and polymerized. Further, when the polymer portion (d) is a composite polymer containing a polymer having a glass transition temperature of −30° C. or less and a polymer having a glass transition temperature of more than −30° C., one polymer has A monomer constituting the other polymer may be polymerized by a known method such as emulsion polymerization or suspension polymerization.

As a method of polymerizing the monomer that is the graft component (e) in the presence of the polymer portion (d), for example, a monomer having a vinyl unit as a main component is polymerized in the presence of the polymer portion (d) latex. methods of polymerizing body components. The graft component (e) may be graft-polymerized in one stage or in multiple stages. From the viewpoint of improving the chemical resistance and maintaining the appearance of the molded product, it is preferable to graft-polymerize the graft component (e) in multiple stages. In particular, as the monomer composition for the first-stage graft polymerization, A monomer composition containing a meth)acrylate, an aromatic (meth)acrylate, and another vinyl monomer is used, and an aromatic ( Using a monomer composition containing an aromatic vinyl monomer that is not meth)acrylate and other vinyl monomers, a (meth)acrylate is used as the monomer composition for the third-stage graft polymerization. , an aromatic (meth)acrylate, and other vinyl monomers are more preferably used.

By adopting the above three-stage polymerization method, chemical resistance can be improved in the first stage of graft polymerization, and good molded appearance can be maintained in the second stage of graft polymerization. Graft polymerization in the second stage can improve chemical resistance.

The obtained latex of the graft copolymer (C) is coagulated by pouring it into hot water in which an acid such as sulfuric acid or hydrochloric acid, an alkaline earth metal salt such as calcium chloride, calcium acetate, magnesium sulfate, or the like is dissolved. , separation and drying to obtain a graft copolymer powder.

In the step of coagulating the latex of the graft copolymer, alkali metal salts such as sodium carbonate and sodium sulfate may be used together. It is also possible to obtain powder directly from latex by a direct drying method such as a spray drying method.

The ratio of the polycarbonate resin (A) in 100 parts by mass of the resin composition is not particularly limited, but is preferably 70 parts by mass or more, more preferably 72.5 parts by mass or more, and 75 parts by mass or more. On the other hand, it is preferably 90 parts by mass or less, more preferably 87.5 parts by mass or less, and even more preferably 85 parts by mass or less.

The proportion of the polymer (B) in 100 parts by mass of the resin composition is not particularly limited, but is preferably 10 parts by mass or more, more preferably 12.5 parts by mass or more, in order to improve surface hardness. , more preferably 15 parts by mass or more, on the other hand, for impact resistance, it is preferably 30 parts by mass or less, more preferably 27.5 parts by mass or less, and 25 parts by mass or less is more preferred.

The proportion of the graft copolymer (C) in 100 parts by mass of the resin composition is not particularly limited, but is preferably 3 parts by mass or more, more preferably 4 parts by mass or more, in order to improve chemical resistance. Preferably, it is more preferably 5 parts by mass or more. On the other hand, it is preferably 30 parts by mass or less, more preferably 27.5 parts by mass or less, in order to suppress a decrease in transparency and a significant increase in haze. It is preferably 25 parts by mass or less, and particularly preferably less than 10 parts by mass.

Moreover, the resin composition may contain other components than the above. Other components are not particularly limited, and include, for example, known antioxidants, ultraviolet absorbers, reinforcing agents, flame retardants, compatibilizers, fillers, talc, and the like. The ratio of other components in 100 parts by mass of the resin composition is preferably 5 parts by mass or less.

Examples of the method for preparing the resin composition according to the present embodiment include known methods used for preparing ordinary resin compositions. For example, the polycarbonate resin (A), the polymer (B), and the graft copolymer (C) are put into a V-type blender, a ribbon mixer, a tumbler, or the like and uniformly mixed, and then a single-screw or twin-screw extruder. etc. to melt and knead. Moreover, after kneading a part of the components in advance, the remaining components may be added and kneaded.

A molded article can be obtained by molding the resin composition according to the present embodiment. As a molding method, a known method such as an extrusion molding method, an injection molding method, a compression molding method, or the like can be used. It can also be applied to a blow molding method, a vacuum molding method, and the like.

Since the molded article has excellent chemical resistance, it can be used in a wide range of fields such as applications requiring chemical resistance such as OA equipment and housings.

EXAMPLES The present invention will be specifically described below with reference to examples.

<Production Example 1>
Production of Graft Copolymer (C-1) The components below were placed in a 70 L autoclave and heated to 43°C.
1,3-butadiene: 100 parts by mass t-dodecylmercaptan: 0.5 parts by mass Sodium hydroxide: 0.01 parts by mass Deionized water: 295 parts by mass Sodium dodecylbenzenesulfonate: 1 part by mass Diisopropylbenzene hydroperoxide: 0.5 part by mass

Subsequently, the following mixture was added to initiate polymerization.
Ferrous sulfate: 0.001 parts by mass EDTA/Na: 0.003 parts by mass Rongalite: 0.15 parts by mass Deionized water: 5 parts by mass

Further, the internal temperature was raised to 65° C. and polymerization was continued for 10 hours to obtain a butadiene polymer (R-1) latex. The final polymerization rate was 95%.

Next, a 5 L separable flask was charged with the following mixture at 20°C.
Polymer (R-1) (as polymer content): 23.8 parts by mass Styrene: 50.7 parts by mass t-butyl hydroperoxide: 0.4 parts by mass Deionized water (including moisture contained in R-1 ): 184.2 parts by mass

Then, after stirring for 1 hour while maintaining the temperature at 20° C., the temperature was raised to 55° C., and then the following mixture was added to initiate polymerization.
Rongalite: 0.1 parts by mass Deionized water: 9.0 parts by mass

Further, the internal temperature was raised to 75° C. and polymerization was continued for 90 minutes to obtain a composite polymer (d-1) composed of a butadiene polymer and polystyrene. The butadiene polymer (R-1), which is a polymer constituting the composite polymer (d-1), has a glass transition temperature of -50°C, and the glass transition temperature of polystyrene is 100°C.

After that, graft polymerization was carried out according to the following procedure.

(Polymerization step of the first stage of grafting)
To 268.2 parts by mass of the composite polymer (d-1), the following mixture was added dropwise over 15 minutes at 75° C. to carry out polymerization, and the polymerization was continued for 90 minutes while maintaining the temperature at 75° C. completed.
Phenyl methacrylate: 4.7 parts by mass Ethyl acrylate: 0.4 parts by mass t-butyl hydroperoxide: 0.02 parts by mass

(Polymerization step of the second stage of grafting)
Next, the following mixture was added dropwise to the obtained polymer at 75° C. over 60 minutes to carry out polymerization. After that, the polymerization was continued for 120 minutes to complete the polymerization.
Styrene: 17.9 parts by mass t-butyl hydroperoxide: 0.07 parts by mass

(Polymerization step of the third stage of grafting)
Thereafter, the following mixture was added dropwise to the obtained polymer at 75° C. over 10 minutes to carry out polymerization. Thereafter, polymerization was continued for 90 minutes to obtain a graft copolymer latex. In addition, the polymerization rate was 99% or more.
Phenyl methacrylate: 2.6 parts by mass t-butyl hydroperoxide: 0.01 parts by mass

(Clot recovery step)
100 parts by mass of the obtained graft copolymer latex was coagulated with 200 parts by mass of a 5% calcium acetate aqueous solution and solidified by heat treatment at 95°C. After that, the coagulate was washed with warm water and dried to obtain a graft copolymer (C-1).

<Production Example 2>
Production of graft copolymer (C-2) The same method as in Example 1, except that the mixture used in the first-stage polymerization step of grafting and the mixture used in the third-stage polymerization step of grafting were changed as follows. to produce a graft copolymer (C-2).

(Mixture used in the polymerization step of the first stage of grafting)
Methyl methacrylate: 4.7 parts by mass Ethyl acrylate: 0.4 parts by mass t-butyl hydroperoxide: 0.02 parts by mass

(Mixture used in the third-stage polymerization step of grafting)
Methyl methacrylate: 2.6 parts by mass t-butyl hydroperoxide: 0.01 parts by mass

<Production Example 3>
Production of graft copolymer (C-3) A composite polymer (C-3) was produced in the same manner as in Production Example 1, except that the amount of R-1 (as the polymer content) was changed to 44 parts by mass and the amount of styrene was changed to 31 parts by mass. d-2), and a graft copolymer (C-3) was obtained in the same manner.

<Production Example 4>
Production of Dispersant L A potassium methacrylate aqueous solution A was obtained by adding the following mixture into a reaction vessel with a capacity of 1200 L equipped with a stirrer, condenser and thermometer and reacting at room temperature.
17 wt% potassium hydroxide aqueous solution: 61.6 parts by mass Methyl methacrylate: 19.1 parts by mass Deionized water: 19.3 parts by mass

Next, the following mixture was added to a 1050 L reaction vessel equipped with a stirrer, a condenser and a thermometer, and the temperature was raised to 50° C. while replacing the inside of the reaction vessel with nitrogen.
Sodium 2-sulfoethyl methacrylate: 60 parts by mass Potassium methacrylate aqueous solution A: 10 parts by mass Methyl methacrylate: 12 parts by mass Deionized water: 900 parts by mass

After that, the following compounds were added, and the temperature was raised to 60°C.
2,2′-azobis(2-methylpropionamidine) dihydrochloride: 0.08 parts by mass

After the temperature was raised, the following compounds were added dropwise over 75 minutes, and then held at 60° C. for 6 hours to obtain Dispersant L having a solid content of 10 parts by mass.
Methyl methacrylate: 18 parts by mass

<Production Example 5>
Production of Polymer (B-1) The following mixture was added to a 5 L separable flask and stirred.
Sodium sulfate: 0.3 parts by mass Dispersant L: 0.26 parts by mass Deionized water: 200 parts by mass

Next, the following mixture was added, and the inside of the reaction vessel was heated to 75° C. while replacing it with nitrogen, maintained for 3 hours, then heated to 85° C. and maintained for 1.5 hours. After that, it was cooled to room temperature to obtain a polymer (B-1). The glass transition temperature of the polymer (B-1) was 153°C. Further, the mass average molecular weight of the polymer (B-1) was 13,000.

Methyl methacrylate: 78.5 parts by mass Phenyl methacrylate: 20 parts by mass Methyl acrylate: 1.5 parts by mass 1-octanethiol: 2 parts by mass 2,2'-azobis(2-methylpropionamidine) dihydrochloride: 0.3 parts by mass

(Particle size measurement)
The average volume particle size of the obtained graft copolymers (C-1) to (C-3) was measured using a CHDF3000 particle size distribution analyzer (model: CHDF3000 model) manufactured by Matec Applied Sciences. Table 1 shows the results obtained. The final component ratio of each component of the graft copolymers (C-1) to (C-3) is shown in Table 1, and the final component ratio of each component of the polymer (B-1) is shown in Table 2. show.

Abbreviations in Table 1 are as follows.
MMA: methyl methacrylate PhMA: phenyl methacrylate EA: ethyl acrylate BA: butyl acrylate MA: methyl acrylate St: styrene Bd: 1,3-butadiene

<Examples 1-2, Comparative Examples 1-4>
Using aromatic polycarbonate (Iupilon S-2000F: manufactured by Mitsubishi Engineering-Plastics Co., Ltd.) as a thermoplastic resin, using graft copolymers (C-1) to (C-3) as impact resistance improvers, It was blended in the ratio shown in 3.
Next, the compound was supplied to a 30 mmΦ twin-screw extruder and melt-kneaded at a cylinder temperature of 260° C. to obtain pellets of the resin composition. After that, the melt flow rate (MFR) of the obtained pellets was measured according to JIS K7210. Table 3 shows the results obtained.

In addition, the pellets were injection molded at a cylinder temperature of 280 ° C and a mold temperature of 80 ° C using an injection molding machine SE100DU (manufactured by Sumitomo Heavy Industries, Ltd.). got a piece The obtained test pieces were measured for transmittance, haze, surface impact resistance, and pencil hardness. Table 3 shows the results obtained. Furthermore, a dumbbell-shaped molded article having a thickness of 4 mm and a total length of 17 cm was obtained by the injection molding described above, and chemical resistance was evaluated. In addition, various evaluations were performed according to the following. Table 3 shows the results obtained.

(Melt flow rate (MFR))
It was carried out according to JIS K7210.

(Transmittance/Haze)
The transmittance and haze were measured according to JIS-K7105.
The transmittance of the molded body is preferably 75% or higher, more preferably 80% or higher, and even more preferably 85% or higher.
Also, the haze of the molded body is preferably 40% or less, more preferably 35% or less, and even more preferably 30% or less.

(Pencil hardness)
According to JIS K5600-5-4, the speed was 60 mm/min, the load was 750 g, and the stroke was 10 mm.
The pencil hardness is preferably B or higher, more preferably HB or higher, and even more preferably F or higher.

(Chemical resistance evaluation)
Nivea hand cream (manufactured by Kao Corporation) was applied to the resulting dumbbell-shaped molded product, and heated at 100° C. for 24 hours while applying stress. Appearance after heating was evaluated. The appearance was observed with an optical microscope. When the number of cracks in the observation field (8100 μm×6000 μm) was 6 or more, it was rated as x, when the number of cracks was 1 to 5, it was rated as Δ, and when no cracks were observed, it was rated as ◯.

From the results of the pencil hardness test of Comparative Examples 3 and 4, it can be seen that the surface hardness is improved by blending the polymer B into the aromatic polycarbonate resin. However, on the other hand, it turns out that chemical resistance is falling. On the other hand, in Comparative Examples 1 and 2, although the graft copolymer (C2) or (C3) was further blended, almost no improvement in chemical resistance was observed, but the graft copolymer according to the present invention ( It can be seen that the chemical resistance is improved in Examples 1 and 2 in which C1) is blended.

Since the resin composition containing the aromatic polycarbonate resin according to the present embodiment has excellent surface hardness and excellent chemical resistance, the resin composition according to the present embodiment is particularly frequently in contact with the human body. It can be used for electronic devices and vehicle members.

Claims (9)

a polycarbonate resin (A);
a polymer (B) containing (meth)acrylate units and having a glass transition temperature of 50° C. or higher;
a graft copolymer (C) in which a (meth)acrylic acid aromatic ester monomer is polymerized to a polymer component containing at least a polymer having a glass transition temperature of −30° C. or lower;
A resin composition comprising: 2. The resin composition according to claim 1, wherein the proportion of the polycarbonate resin (A) in 100 parts by mass of the resin composition is 70 parts by mass or more and 90 parts by mass or less. The resin composition according to claim 1 or 2, wherein the proportion of said polymer (B) in 100 parts by mass of the resin composition is 10 parts by mass or more and 30 parts by mass or less. 4. The resin composition according to any one of claims 1 to 3, wherein the proportion of said graft copolymer (C) in 100 parts by mass of the resin composition is 3 parts by mass or more and 30 parts by mass or less. The resin composition according to any one of claims 1 to 4, wherein the proportion of (meth)acrylate in 100 parts by mass of the polymer (B) is 50 parts by mass or more. The resin composition according to any one of claims 1 to 5, wherein the polymer (B) has a mass average molecular weight of 5,000 or more and 30,000 or less. The proportion of the polymer component in 100 parts by mass of the graft copolymer (C) is 40 parts by mass or more and 90 parts by mass or less, and the glass transition temperature in 100 parts by mass of the polymer component is −30° C. or less. The resin composition according to any one of claims 1 to 6, wherein the proportion of the polymer is 10 parts by mass or more and 55 parts by mass or less. In 100 parts by mass of the graft copolymer (C), the proportion of (meth)acrylic acid aromatic ester units polymerized in the polymer component containing at least the polymer having a glass transition temperature of −30° C. or lower is 1 mass. The resin composition according to any one of claims 1 to 7, which is 1 part or more and 20 parts by mass or less. A molded article obtained by molding the resin composition according to any one of claims 1 to 8.