JP2022143020A - Polymer and polycarbonate resin composition - Google Patents

Abstract

To provide: a polymer which, even when added to a polycarbonate resin derived from biomass, realizes excellent flowability of a polycarbonate resin composition and can inhibit optical properties and heat resistance from declining; and a polycarbonate resin composition based on the polymer.SOLUTION: A polymer is mixed in a polycarbonate resin composition, the polymer comprising a constitutional unit (a1) derived from a compound represented by the formula (1), where R1 is a hydrogen atom or C1-5 alkyl group, and a constitutional unit (a2) derived from methyl methacrylate, the polymer having a number-average molecular weight from 5000 to 30000.SELECTED DRAWING: None

Description

The present invention relates to polymer and polycarbonate resin compositions.

In recent years, the development of biomass-derived resins has been active toward the construction of a carbon recycling society, and the development of applications such as electrical equipment, electronic equipment, OA equipment, automobile parts, building parts, etc. is progressing. In order to expand into these applications, high optical properties (high transparency) for high color development, high heat resistance that does not deform due to the temperature of the usage environment, and high fluidity that facilitates processing into complex shapes are required. . Therefore, studies are also underway to meet the performance requirements for these applications by combining biomass-derived resins with other resin materials.

For example, Patent Document 1 contains a biomass-derived resin (A), a resin (B) incompatible with the resin (A), and a plasticizer (C), and the content of the resin (B) is higher than the resin (B). A resin composition is disclosed in which the content of (A) is greater and the glass transition temperature of resin (A) is higher than that of resin (B).

Japanese Patent Application Laid-Open No. 2020-37608

However, in the resin composition described in Patent Literature 1, the biomass-derived resin (A) and the resin (B) are not compatible with each other, so the optical properties and heat resistance are insufficient.

The present invention provides a polymer that has excellent fluidity of a polycarbonate resin composition even when blended in a biomass-derived polycarbonate resin and that can suppress deterioration of optical properties and heat resistance, and a polycarbonate resin composition using the polymer. offer.

The present invention includes the following aspects.
[1] A polymer having a structural unit (a1) derived from a compound represented by the following formula (1) and a structural unit (a2) derived from methyl methacrylate, and having a number average molecular weight of 5,000 to 30,000.

(In formula (1) above, R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.)
[2] The polymer according to [1], wherein the ratio of the structural unit (a1) to the total of all structural units is 3 to 35% by mass.
[3] The polymer according to [1] or [2], wherein the ratio of the structural unit (a1) to the total of all structural units is 3 to 25% by mass.
[4] The polymer according to any one of [1] to [3], which has a number average molecular weight of 7,000 to 20,000.
[5] The polymer according to any one of [1] to [4], which is a polymer for blending into a biomass-derived polycarbonate resin.
[6] It has a structural unit (b1) derived from a dihydroxy compound represented by the following formula (2) and a structural unit (b2) derived from a dihydroxy compound other than the dihydroxy compound represented by the following formula (2) The polymer according to [5], which is a polymer for compounding into a polycarbonate resin.

[7] A structural unit (b1) comprising the polymer according to any one of [1] to [4] and a polycarbonate resin, wherein the polycarbonate resin is derived from the dihydroxy compound represented by the formula (2); and a structural unit (b2) derived from a dihydroxy compound other than the dihydroxy compound represented by the formula (2).
[8] The polycarbonate resin composition according to [7], wherein the ratio of the structural unit (b1) to the total of all structural units of the polycarbonate resin is 40 to 90% by mass.
[9] The polycarbonate resin composition according to [7] or [8], wherein the proportion of the polymer to the total of the polymer and the polycarbonate resin is 10 to 40% by mass.

INDUSTRIAL APPLICABILITY According to the present invention, a polymer that has excellent fluidity in a polycarbonate resin composition even when blended in a biomass-derived polycarbonate resin and that can suppress deterioration in optical properties and heat resistance, and a polycarbonate resin composition using the polymer. can provide things.

[Explanation of terms]
The following term definitions apply throughout the specification and claims.
"Structural unit" means a structural unit derived from a monomer, that is, a structural unit formed by polymerizing a monomer, or a part of a structural unit is converted to another structure by treating a polymer. means a building block.
"Number average molecular weight" is the polymethyl methacrylate equivalent number average molecular weight measured by gel permeation chromatography.

[Polymer]
The polymer according to the present invention includes a structural unit (a1) derived from a compound represented by the following formula (1) (hereinafter also referred to as "compound (1)") and a structural unit (a2) derived from methyl methacrylate (hereinafter also referred to as "polymer (A)"). The polymer (A) may have structural units (a3) derived from other monomers, if necessary.

However, in the above formula (1), R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

The polymer (A) has a number average molecular weight of 5,000 to 30,000. When the polymer (A) has a number average molecular weight of 5000 or more, a polycarbonate resin composition having excellent heat resistance can be obtained when blended with a biomass-derived polycarbonate resin. When the number average molecular weight of the polymer (A) is 30,000 or less, a polycarbonate resin composition having excellent fluidity and optical properties can be obtained. The lower limit of the number average molecular weight of the polymer (A) is preferably 7000 or more, more preferably 8000 or more. The upper limit of the number average molecular weight of the polymer (A) is preferably 20,000 or less, more preferably 15,000 or less.

By blending the polymer (A) with a biomass-derived polycarbonate resin, it is possible to obtain a polycarbonate resin composition excellent in fluidity, optical properties and heat resistance as described above. As the biomass-derived polycarbonate resin, from the viewpoint of good compatibility with the polymer (A), a polycarbonate resin (B) described later is preferable.

(Constituent unit (a1))
Structural unit (a1) is a structural unit derived from compound (1). When the polymer (A) has the structural unit (a1), the compatibility between the polymer (A) and the biomass-derived polycarbonate resin is improved. Accordingly, by blending the polymer (A) with a biomass-derived polycarbonate resin, a polycarbonate resin composition having excellent optical properties and heat resistance can be obtained. As the structural unit (a1), only one type may be used, or two or more types may be present.

From the viewpoint of heat resistance of the resulting polycarbonate resin composition, the structural unit (a1) is preferably a compound represented by formula (1) in which R ¹ is an alkyl group having 1 carbon atom, more preferably methacrylic acid (2- A structural unit derived from oxo-1,3-dioxolan-4-yl)methyl is preferred.

The ratio of the structural unit (a1) to the total of all structural units of the polymer (A) is preferably 3 to 35% by mass. When the ratio of the structural unit (a1) is 3% by mass or more, it becomes easier to obtain a polycarbonate resin composition having excellent optical properties. When the proportion of the structural unit (a1) is 35% by mass or less, it becomes easier to obtain a polycarbonate resin composition with excellent fluidity. The proportion of the structural unit (a1) is more preferably 3 to 30% by mass, even more preferably 3 to 25% by mass.

(Constituent unit (a2))
The structural unit (a2) is a structural unit derived from methyl methacrylate. Since the polymer (A) has the structural unit (a2), it is possible to obtain a polycarbonate resin composition having excellent fluidity when blended with a polycarbonate resin.

The ratio of the structural unit (a2) to the total of all structural units of the polymer (A) is preferably 55-95% by mass. When the ratio of the structural unit (a2) is 55% by mass or more, it becomes easier to obtain a polycarbonate resin composition having excellent fluidity. When the ratio of the structural unit (a2) is 95% by mass or less, it becomes easier to obtain a polycarbonate resin composition having excellent optical properties. The lower limit of the ratio of the structural unit (a2) is more preferably 65% by mass or more, and even more preferably 70% by mass or more. The upper limit of the proportion of the structural unit (a2) is more preferably 90% by mass or less, and even more preferably 85% by mass or less.

(Constituent unit (a3))
Structural unit (a3) is a structural unit derived from a monomer other than compound (1) and methyl methacrylate. As the structural unit (a3), only one type may be used, or two or more types may be present.

Other monomers include, for example, methacrylates other than methyl methacrylate such as ethyl methacrylate, butyl methacrylate, propyl methacrylate, 2-ethylhexyl methacrylate; methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, 2-ethylhexyl acrylate, glycidyl Acrylates, phenyl acrylate, 1-naphthyl acrylate, 2-naphthyl acrylate, p-diphenyl acrylate, o-diphenyl acrylate, o-chlorophenyl acrylate, 4-methoxyphenyl acrylate, 4-chlorophenyl acrylate, 2,4,6-trichlorophenyl acrylate , 4-tert-butylphenyl acrylate; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; diene monomers such as butadiene, isoprene and dimethylbutadiene; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether Carboxylic acid vinyl monomers such as vinyl acetate and vinyl butyrate; Olefin monomers such as ethylene, propylene and isobutylene; Vinyl halide monomers such as vinyl chloride and vinylidene chloride; -Phenylmaleimide, N-cyclohexylmaleimide, N-methylmaleimide and other maleimide monomers.

Other monomers may be cross-linking agents such as allyl (meth)acrylate, divinylbenzene, 1,3-butylene dimethacrylate and the like.
The other monomers are preferably methacrylate, acrylate, and vinyl cyanide monomers from the viewpoint of easy production of the polymer (A), and from the viewpoint of suppressing thermal decomposition of the polymer (A). , more preferably an acrylate.

The content of the structural unit (a3) with respect to the total of all structural units of the polymer (A) is preferably 10% by mass or less from the viewpoint of the heat resistance of the resulting polycarbonate resin composition.

Polymer (A) can be produced by polymerizing compound (1), methyl methacrylate, and optionally other monomers. The polymerization method includes known suspension polymerization method, solution polymerization method, emulsion polymerization method, bulk polymerization method and the like.

When the polymer (A) is produced by suspension polymerization, it is preferred to use a dispersant. This improves the dispersion stability of the polymer (A) in the solvent during polymerization. As the dispersant, surfactants, polyvinyl alcohol, polyethylene glycol, methacrylate polymers having ionic groups, and the like can be used. Examples of the methacrylate-based polymer having an ionic group include polymers containing structural units derived from sodium methacrylate, potassium methacrylate, sodium methacrylate sulfonate, sodium ethyl methacrylate sulfonate, and the like. A dispersing agent may be used individually by 1 type, and may use 2 or more types together.

[Polycarbonate resin composition]
A polycarbonate resin composition according to the present invention contains a polymer (A) and a polycarbonate resin (B). By including the polymer (A) having good compatibility with the polycarbonate resin (B), the polycarbonate resin composition has good optical properties and heat resistance. The polycarbonate resin composition may contain components other than the polymer (A) and the polycarbonate resin (B), if necessary.
The resin composition according to the present invention may be molded into a desired shape according to the application to form a molded body. As a molding method, a known method such as an injection molding method, an extrusion molding method, a compression molding method, or the like can be used.

The ratio of polymer (A) to the total of polymer (A) and polycarbonate resin (B) is preferably 1 to 40% by mass. When the polymer (A) is 1% by mass or more, the polycarbonate resin composition has good optical properties. When the polymer (A) is 40% by mass or less, the polycarbonate resin composition has good fluidity. The lower limit of the proportion of polymer (A) is more preferably 5% by mass or more, and even more preferably 10% by mass or more. The upper limit of polymer (A) is more preferably 35% by mass or less, and even more preferably 30% by mass or less.

The polycarbonate resin composition according to the present invention can be produced by melt-kneading the polymer (A), the polycarbonate resin (B), and, if necessary, other components. Examples of melt-kneading devices include Banbury mixers, kneaders, rolls, kneader rolls, single-screw extruders, twin-screw extruders, and multi-screw extruders.

(Polycarbonate resin (B))
The polycarbonate resin (B) comprises a structural unit (b1) derived from a dihydroxy compound represented by the following formula (2) (hereinafter also referred to as "dihydroxy compound (2)"), and a dihydroxy compound other than the dihydroxy compound (2). It has a structural unit (b2) derived from a compound (hereinafter also referred to as "dihydroxy compound (3)").

<Constituent unit (b1)>
The structural unit (b1) is a structural unit derived from the dihydroxy compound (2).
Examples of dihydroxy compounds (2) include biomass-derived isosorbide, isomannide, and isoidet. Among them, isosorbide is preferable from the viewpoint of excellent optical properties of the polycarbonate resin composition.

The ratio of the structural unit (b1) to the total of all structural units of the polycarbonate resin (B) is preferably 40 to 90% by mass. When the structural unit (b1) is 40% by mass or more, the polycarbonate resin composition has good heat resistance. When the structural unit (b1) is 90% by mass or less, the polycarbonate resin composition has good fluidity. The lower limit of the ratio of the structural unit (b1) is more preferably 45% by mass or more. Moreover, the upper limit of the structural unit (b1) is more preferably 85% by mass or less, and even more preferably 80% by mass or less.

<Constituent unit (b2)>
The structural unit (b2) is a structural unit derived from the dihydroxy compound (3). In addition, as a structural unit (b2), only 1 type may be sufficient and 2 or more types may exist.
The dihydroxy compound (3) is preferably any one selected from the group consisting of aliphatic dihydroxy compounds, alicyclic dihydroxy compounds and aromatic dihydroxy compounds. In particular, from the viewpoint of excellent mechanical properties of the polycarbonate resin composition, alicyclic dihydroxy compounds are preferred, and specific examples include 1,4-cyclohexanedimethanol and tricyclodecanedimethanol.

The ratio of the structural unit (b2) to the total of all structural units of the polycarbonate resin (B) is preferably 10 to 60% by mass. When the structural unit (b2) is 10% by mass or more, the polycarbonate resin composition has good fluidity. When the structural unit (b2) is 60% by mass or less, the polycarbonate resin composition has good heat resistance. The lower limit of the ratio of the structural unit (b2) is more preferably 15% by mass or more, and even more preferably 20% by mass or more. More preferably, the upper limit of the ratio of the structural unit (b2) is 55% by mass or less.

The polycarbonate resin (B) can be obtained, for example, by polycondensing the dihydroxy compound (2), the dihydroxy compound (3), and optionally the carbonic acid diester as raw materials through a transesterification reaction.
Carbonic acid diesters include, for example, diphenyl carbonate, ditolyl carbonate, dimethyl carbonate, diethyl carbonate, di-t-butyl carbonate and the like. Among them, diphenyl carbonate is preferable from the viewpoint of excellent optical properties of the polycarbonate resin composition. Carbonic acid diesters may be used singly or in combination of two or more.

A commercially available product may be used as the polycarbonate resin (B). Examples of commercially available products include Durabio D7340, Durabio D6350, Durabio D5380 and Durabio D5360 manufactured by Mitsubishi Chemical Corporation.

The polycarbonate resin composition according to the present invention may contain other resins than the polymer (A) and the polycarbonate resin (B) within a range that does not impair the effects of the present invention. If necessary, various additives (antioxidants, ultraviolet absorbers, light stabilizers, flame retardants, etc.), various fillers (glass, mica, rubber particles, etc.) and the like may be included.

EXAMPLES The present invention is illustrated below by way of examples. In the examples, the ratio of each structural unit of the polymer (A) and the method for determining the number average molecular weight and the method for evaluating the polycarbonate resin composition are as follows. "Parts" in the examples means "mass parts", and "%" means "% by mass".

(percentage of constituent units)
The ratio of each structural unit in the polymer (A) and the polycarbonate resin composition was calculated from the charged amounts of the monomers.

(Number average molecular weight)
The number average molecular weight of polymer (A) was measured as follows. First, the elution curve of polymer (A) dissolved in tetrahydrofuran was measured by gel permeation chromatography using tetrahydrofuran as an eluent at a column temperature of 40°C. Then, the number average molecular weight of the polymer (A) was calculated based on the standard curve of polymethyl methacrylate.

(optical properties)
The optical properties of the polycarbonate resin composition were evaluated by total light transmittance and haze. High total light transmittance and low haze indicate good optical properties. The total light transmittance and haze were measured on a polycarbonate resin composition having a thickness of 2 mm according to JIS K 7136 using a haze meter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

(Liquidity)
The fluidity of the polycarbonate resin composition was evaluated by melt flow rate (MFR). High fluidity indicates good fluidity. MFR was measured on a pellet-shaped resin composition in accordance with JIS K-7210 under conditions of 230° C. and a load of 2.16 kgf.

(Heat-resistant)
The heat resistance of the polycarbonate resin composition was evaluated by the deflection temperature under load. A high deflection temperature under load indicates good heat resistance. Deflection temperature under load was measured in accordance with JIS K 7191-1 for a polycarbonate resin composition molded into a size of 80 mm long×10 mm wide×4 mm thick.

[Production Example 1]
(Production of polymer (A))
61.6 parts of a 17% potassium hydroxide aqueous solution and 19.1 parts of Acryester M (methyl methacrylate, trade name, manufactured by Mitsubishi Chemical Corporation) were placed in a 1200 L reaction vessel equipped with a stirrer, a cooling pipe and a thermometer. and 19.3 parts of deionized water were added. The resulting mixture was stirred at room temperature, and after an exothermic peak was confirmed, the mixture was further stirred for 4 hours. After that, the mixed liquid was cooled to room temperature to obtain an aqueous potassium methacrylate solution.

Then, 900 parts of deionized water, 10 parts of the resulting potassium methacrylate aqueous solution, Acryester SEM-Na (Mitsubishi Chemical Corporation methacrylic 60 parts of acid 2-sulfoethyl sodium (trade name, 42% by mass aqueous solution) and 12 parts of Acryester M were added and stirred, and the temperature was raised to 50° C. while replacing the inside of the reaction vessel with nitrogen. Subsequently, 0.08 part of V-50 (2,2′-azobis(2-methylpropionamidine) dihydrochloride manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name) was added as a polymerization initiator, and 60 °C. After the temperature was raised, Acryester M was continuously added dropwise for 75 minutes at a rate of 0.24 parts/minute. The obtained solution was held at 60° C. for 6 hours and then cooled to room temperature to obtain a dispersant having a solid content of 10% by mass.

Subsequently, as shown below, a polymer (A- 1) was manufactured. Table 1 shows the ratio of each structural unit to the total of all structural units of the polymer (A-1) and the number average molecular weight.

200 parts of deionized water, 0.26 parts of the dispersant obtained above, and 0.3 parts of sodium sulfate (Na ₂ SO ₄ ) were added into a polymerization apparatus equipped with a stirrer, condenser and thermometer. Stir to form a homogeneous aqueous solution.
Then, DOMA (manufactured by NOF Corporation, (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate, trade name) 5 parts, Acryester M (manufactured by Mitsubishi Chemical Corporation, methyl methacrylate, Trade name) 93 parts, 2 parts of methyl acrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., special reagent grade), and 2 parts of 1-octanethiol (manufactured by Tokyo Chemical Industry Co., Ltd.) as a chain transfer agent, and 2 parts as a polymerization initiator 0.3 parts of AMBN (trade name of 2,2-azobis-2-methylbutyronitrile manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to prepare an aqueous dispersion. Next, the inside of the polymerization apparatus was sufficiently replaced with nitrogen, and the resulting aqueous dispersion was heated to 75° C. and held for 3 hours, then heated to 85° C. and held for 1.5 hours to carry out polymerization. rice field. After cooling to 40° C., an aqueous suspension containing polymer (A-1) was obtained. This aqueous suspension was filtered with a filter cloth, and the filtrate was washed with deionized water and dried at 75° C. for 18 hours to obtain polymer (A-1).

[Production Examples 2 to 4]
Polymers (A-2) to (A-4) having the structural unit (a1) and structural unit (a2) ratios shown in Table 1 were obtained in the same manner as in Production Example 1.

[Production Examples 5 and 6]
Polymers (X-1) to (X-2) having the structural unit (a1) and structural unit (a2) ratios shown in Table 1 were obtained in the same manner as in Production Example 1.

[Example 1]
20 parts of the polymer (A-1) and 80 parts of Durabio D7340 (manufactured by Mitsubishi Chemical Corporation) containing 70% by mass of the structural unit (b1) as the polycarbonate resin (B-1) were placed in a polyethylene bag, Shake well and hand blend. The resulting mixture was melt-kneaded at 250° C. using a twin-screw extruder (TEM35B, manufactured by Toshiba Machine Co., Ltd.), extruded and cut to obtain a pellet-like polycarbonate resin composition. Table 2 shows the results of evaluating the fluidity of the polycarbonate resin composition.
Next, the obtained pellet-shaped polycarbonate resin composition is molded at a molding temperature of 250° C. and a mold temperature of 80° C. using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., IS-100 molding machine). A polycarbonate resin composition molded into a shape corresponding to the evaluation was obtained. Table 2 shows the results of evaluating the optical properties and heat resistance of the molded polycarbonate resin composition.

[Example 2]
A polycarbonate resin composition was obtained in the same manner as in Example 1, except that the polymer (A-1) was changed to the polymer (A-2). Table 2 shows the evaluation results of fluidity, optical properties and heat resistance of the polycarbonate resin composition.

[Example 3]
A polycarbonate resin composition was obtained in the same manner as in Example 1, except that the polymer (A-1) was changed to the polymer (A-3). Table 2 shows the evaluation results of fluidity, optical properties and heat resistance of the polycarbonate resin composition.

[Example 4]
The polymer (A-1) is changed to the polymer (A-3), and Durabio D5380 (manufactured by Mitsubishi Chemical Corporation) containing 50% by mass of the structural unit (b1) is used as the polycarbonate resin (B-2). A polycarbonate resin composition was obtained in the same manner as in Example 1, except that Table 2 shows the evaluation results of fluidity, optical properties and heat resistance of the polycarbonate resin composition.

[Example 5]
The same operation as in Example 1 was performed except that the polymer (A-1) was changed to the polymer (A-4) and the polycarbonate resin (B-1) was changed to the polycarbonate resin (B-2). A polycarbonate resin composition was obtained. Table 2 shows the evaluation results of fluidity, optical properties and heat resistance of the polycarbonate resin composition.

[Comparative Example 1]
A polycarbonate resin composition was obtained in the same manner as in Example 1, except that the polymer (A-1) was changed to the polymer (X-1). Table 2 shows the evaluation results of fluidity, optical properties and heat resistance of the polycarbonate resin composition.

[Comparative Example 2]
A polycarbonate resin composition was obtained in the same manner as in Example 1, except that the polymer (A-1) was changed to the polymer (X-2). Table 2 shows the evaluation results of fluidity, optical properties and heat resistance of the polycarbonate resin composition.

[Comparative Example 3]
A polycarbonate resin composition was obtained in the same manner as in Example 1, except that the polymer (A-1) was changed to polylactic acid (Ingeo 3001D, manufactured by Nature Works). Table 2 shows the evaluation results of fluidity, optical properties and heat resistance of the polycarbonate resin composition.

[Reference example 1]
Only the polycarbonate resin (B-1) was melt-kneaded at 250° C. using a twin-screw extruder (TEM35B, manufactured by Toshiba Machine Co., Ltd.), and the extruded strand was cut to obtain pellets.
Using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., IS-100 molding machine), the obtained pellets are molded at a molding temperature of 250 ° C. and a mold temperature of 80 ° C., and a polycarbonate resin composition having a shape according to each evaluation. got Table 2 shows the evaluation results of fluidity, optical properties and heat resistance of the polycarbonate resin composition.

[Reference example 2]
Using only the polycarbonate resin (B-2), the same operation as in Reference Example 1 was performed to obtain a polycarbonate resin composition. Table 2 shows the evaluation results of fluidity, optical properties and heat resistance of the polycarbonate resin composition.

As shown in Table 1, Examples 1 to 3, in which the predetermined polymer (A) was blended with the polycarbonate resin (B-1), were compared to Reference Example 1, which contained only the polycarbonate resin (B-1). , had improved liquidity. Similarly, Examples 4 and 5, in which the prescribed polymer (A) was blended with the polycarbonate resin (B-2), had improved fluidity compared to Reference Example 2, which contained only the polycarbonate resin (B-2). Was. Further, these Examples 1 to 5 were also good in optical properties and heat resistance.

On the other hand, Comparative Example 1 in which the polymer (X-1) having no structural unit (a1) was blended with the polycarbonate resin (B-1) had lower optical properties and heat resistance than Examples 1 to 3. result. Further, Comparative Example 2 in which the number average molecular weight of the polymer (X-2) is larger than the specified range, and Comparative Example 3 in which polylactic acid is used as the polymer have better fluidity and optical properties than those in Examples 1 to 3. a low result.

INDUSTRIAL APPLICABILITY The resin composition of the present invention is useful for applications such as members of various devices (electrical devices, electronic devices, OA devices, etc.), automobile members (automobile headlamps, automobile interior materials, etc.), construction members, and the like.

Claims (9)

A polymer having a structural unit (a1) derived from a compound represented by the following formula (1) and a structural unit (a2) derived from methyl methacrylate, and having a number average molecular weight of 5,000 to 30,000.

(In formula (1) above, R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.) 2. The polymer according to claim 1, wherein the ratio of said structural unit (a1) to the total of all structural units is 3 to 35% by mass. 3. The polymer according to claim 1, wherein the ratio of said structural unit (a1) to the total of all structural units is 3 to 25% by mass. The polymer according to any one of claims 1 to 3, having a number average molecular weight of 7,000 to 20,000. The polymer according to any one of claims 1 to 4, which is a polymer for incorporation into a biomass-derived polycarbonate resin. To a polycarbonate resin having a structural unit (b1) derived from a dihydroxy compound represented by the following formula (2) and a structural unit (b2) derived from a dihydroxy compound other than the dihydroxy compound represented by the following formula (2) 6. The polymer of claim 5, which is a polymer for compounding of

The polymer according to any one of claims 1 to 4, and a polycarbonate resin,
The polycarbonate resin comprises a structural unit (b1) derived from a dihydroxy compound represented by the following formula (2), and a structural unit (b2) derived from a dihydroxy compound other than the dihydroxy compound represented by the following formula (2). A polycarbonate resin composition.

8. The polycarbonate resin composition according to claim 7, wherein the ratio of said structural unit (b1) to the total of all structural units of said polycarbonate resin is 40 to 90% by mass. 9. The polycarbonate resin composition according to claim 7, wherein the proportion of said polymer with respect to the total of said polymer and said polycarbonate resin is 10 to 40% by mass.