JP5107163B2 - Thermoplastic resin composition and injection molded product using the same - Google Patents

Description

  The present invention relates to a thermoplastic resin composition from which a molded product excellent in surface hardness and transparency can be obtained, and an injection molded product using the same.

  Polycarbonate is widely used in electrical and electronic / OA equipment, optical media, automobile parts, building members, etc. due to its excellent mechanical strength, heat resistance, electrical properties, dimensional stability, flame retardancy, transparency, and the like.

  Such polycarbonate is usually a method of directly reacting an aromatic dihydroxy compound such as bisphenol A and phosgene (phosgene method), or a method of transesterifying an aromatic dihydroxy compound and a carbonic diester such as diphenyl carbonate (transesterification). Etc.).

  A polycarbonate molded article produced using bisphenol A as an aromatic dihydroxy compound may not have sufficient hardness. For example, in applications that are used outdoors such as automobile headlamps, eyeglass lenses, or sheets, polycarbonate molded products have insufficient hardness (surface hardness), so a hard coat layer is provided to increase the surface hardness. I make up for it. However, since the hard coat layer is provided by coating after the molding of the polycarbonate, the number of molding steps of the molded product increases, resulting in an increase in cost, and sufficient surface hardness and transparency may not be obtained in the molded product. .

  In addition, as a method for improving the surface hardness of a polycarbonate molded product, a method of blending an acrylic resin having a specific molecular weight to give a molded product while maintaining transparency (Patent Document 1), a carbonate ester copolymer having a specific structure A method using coalescence (Patent Document 2) has been reported.

  However, since the above method does not require a step after hot melt molding, it is advantageous in terms of manufacturing steps, but it is difficult to achieve a balance between physical properties of sufficient surface hardness and transparency. The carbonate ester copolymer described in Patent Document 2 requires the use of a special aromatic dihydroxy compound in a relatively large amount of 50 mol% to 90 mol%. There are issues to include.

Therefore, there is a demand for the development of a polycarbonate that is excellent in transparency and can provide a molded product having excellent surface hardness that can be used for outdoor use without providing a hard coat layer or the like on the surface. .
JP 62-131056 A Japanese Patent Laid-Open No. 08-183852

  An object of the present invention is to provide a thermoplastic resin composition containing polycarbonate, which does not require a hard coat layer on the surface, has surface hardness, and can efficiently and inexpensively produce a molded article having excellent transparency. It is to provide an injection molded product used.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that polymethyl methacrylate having a specific molecular weight is compatible with polycarbonate, and further, polyaromatic (meth) acrylate having a specific structure is further interlinked. The compatibility of these can be improved, and when they are sufficiently compatible, the hardness of the resulting molded product can be increased and the hard coat layer on the surface can be dispensed with. . Based on this finding, the present invention has been completed.

  That is, in the present invention, 0.1 to 15 parts by mass of a polymer (B) containing 50% by mass or more of an aromatic (meth) acrylate unit and 100 parts by mass of a polycarbonate (A), and a methyl methacrylate unit. The present invention relates to a thermoplastic resin composition obtained by blending 5 to 70 parts by mass of a polymer (C) containing 60% by mass or more and having a mass average molecular weight of 5,000 to 20,000.

  The present invention also relates to an injection molded product obtained by using the thermoplastic resin composition.

  The thermoplastic resin composition of the present invention does not require a hard coat layer on the surface, has a surface hardness, and can efficiently produce a molded product having excellent transparency.

  The thermoplastic resin composition of the present invention is 0.1 to 15 parts by mass of a polymer (B) containing 50% by mass or more of an aromatic (meth) acrylate unit with respect to 100 parts by mass of the polycarbonate (A), and It is obtained by blending 5 to 70 parts by mass of a polymer (C) containing 60% by mass or more of methyl methacrylate units and having a mass average molecular weight (hereinafter referred to as “Mw”) of 5,000 to 20,000.

  The polycarbonate (A) used in the present invention is an aliphatic polycarbonate in which R is an aliphatic group as long as it has a — [O—R—OCO] — unit containing a carbonate ester bond in the molecular main chain, R May be any of an aromatic polycarbonate in which is an aromatic group, and R is an aliphatic / aromatic polycarbonate having both an aliphatic group and an aromatic group.

  As the polycarbonate (A), an aromatic polycarbonate obtained using an aromatic dihydroxy compound such as bisphenol A is particularly preferable from the viewpoint of economy.

  The viscosity average molecular weight (hereinafter referred to as “Mv”) of the polycarbonate (A) is preferably 15,000 to 30,000, more preferably 17,000 to 25,000. If Mv is in the above range, the compatibility with the polymer (B) and the polymer (C) is good, and the effect of improving the surface hardness is excellent.

  As a manufacturing method of the said polycarbonate (A), a phosgene method, a transesterification method, etc. can be selected suitably.

  It is also possible to apply what is marketed as polycarbonate. For example, Iupilon S-2000F (trade name, manufactured by Mitsubishi Engineering Plastics Co., Ltd., Mv: 24,000), Tufflon FN1700 (trade name, Idemitsu Kosan Co., Ltd.) , Mv: 18,000), etc. can be used.

  The polymer (B) used in the present invention contains 50% by mass or more of an aromatic (meth) acrylate unit, and has an effect of improving the compatibility between the polycarbonate (A) and the polymer (C). .

  Here, the aromatic (meth) acrylate includes a methacrylate having an aromatic group in the ester portion, an acrylate having an aromatic group in the ester portion, or both, and the polymer (B) is aromatic. It is a polymer containing a (meth) acrylate unit.

  Examples of the aromatic (meth) acrylate constituting the aromatic (meth) acrylate unit include phenyl methacrylate, benzyl methacrylate, phenyl acrylate, and benzyl acrylate. These may be used alone or in combination of two or more.

  Among these, phenyl methacrylate and benzyl methacrylate are preferable, and phenyl methacrylate is more preferable.

  The content rate of an aromatic (meth) acrylate unit in a polymer (B) (100 mass%) is 50 mass% or more.

  When the content of the aromatic (meth) acrylate unit in the polymer (B) (100% by mass) is 50% by mass or more, the compatibility with the polycarbonate (A) is improved. In order to improve the compatibility with the polycarbonate (A), the content of the aromatic (meth) acrylate unit in the polymer (B) is preferably 60% by mass or more, and more preferably 70% by mass or more.

  Moreover, 99.5 mass% or less is preferable and, as for the upper limit of the content rate of an aromatic (meth) acrylate unit in a polymer (B) (100 mass%), 99 mass% or less is more preferable.

  The polymer (B) (100% by mass) may contain other monomer units in a range of less than 50% by mass. The other monomer unit should just be a unit by the monomer which can be copolymerized with aromatic (meth) acrylate, and an (alpha), (beta)-unsaturated monomer unit is preferable.

  Examples of such monomers include alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and 2-ethylhexyl methacrylate; alkyl acrylates such as methyl acrylate, ethyl acrylate, and butyl acrylate; aromatics such as styrene, α-methyl styrene, and vinyl toluene. Vinyl compounds; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile are listed. These may be used alone or in combination of two or more.

  The Mw of the polymer (B) is preferably 300,000 to 5,000,000, more preferably 400,000 to 3,000,000, still more preferably 600,000 to 2,000,000, and particularly preferably 800,000 to 1.3 million.

  If Mw of a polymer (B) is the said range, high transparency and surface hardness can be achieved in the molded article obtained.

  As a production method of the polymer (B), an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, a bulk polymerization method and the like can be used. The emulsion polymerization method and the suspension polymerization method are preferable, and the emulsion polymerization method is more preferable.

  In the case of the emulsion polymerization method, the polymer is generally recovered after polymerization by a method such as acid precipitation coagulation, salting out coagulation, or spray drying.

  The polymer (C) used in the present invention contains 60% by mass or more of methyl methacrylate units and has a Mw of 5,000 to 20,000. Such a polymer (C) is compatible with the polycarbonate (A) and has an action of improving the surface hardness of the obtained molded product.

  The content of the methyl methacrylate unit in the polymer (C) (100% by mass) is 60% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more.

  Moreover, 99.5 mass% or less is preferable and, as for the upper limit of the content rate of the methylmethacrylate unit in a polymer (C) (100 mass%), 99 mass% or less is more preferable.

  If the content rate of the methyl methacrylate unit in a polymer (C) (100 mass%) is the said range, the molded article which is excellent in surface hardness can be obtained.

  The polymer (C) (100% by mass) may contain other monomer units in a range of less than 40% by mass. Other monomer units may be units based on monomers copolymerizable with methyl methacrylate, and α, β-unsaturated monomer units are preferable.

  Examples of such monomers include alkyl methacrylates such as ethyl methacrylate, butyl methacrylate and 2-ethylhexyl methacrylate; alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate; phenyl methacrylate, benzyl methacrylate and phenyl acrylate. And aromatic (meth) acrylates such as benzyl acrylate; aromatic vinyl compounds such as styrene, α-methylstyrene and vinyltoluene; and vinyl cyanide compounds such as acrylonitrile and methacrylonitrile. These may be used alone or in combination of two or more.

  In these, alkyl acrylates, such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and styrene are preferable.

  Mw of the polymer (C) is 5,000 or more, preferably 7,000 or more, more preferably 9,000 or more.

  If the Mw of the polymer (C) is 5,000 or more, the resulting molded article has excellent surface hardness. If Mw of a polymer (C) is less than 5000, since the glass transition temperature of a polymer (C) will fall, the improvement effect of surface hardness may fall in the molded article obtained.

  Moreover, Mw of a polymer (C) is 20,000 or less, Preferably it is 15,000 or less, More preferably, it is 13,000 or less.

  When the Mw of the polymer (C) is 20,000 or less, the compatibility with the polycarbonate (A) is good, and the effect of improving the surface hardness is excellent.

  As a production method of the polymer (C), an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, a bulk polymerization method and the like can be used. The bulk polymerization method and the suspension polymerization method are preferable, and the suspension polymerization method is more preferable.

  Content of the polymer (B) in the thermoplastic resin composition of this invention is 0.1-15 mass parts with respect to 100 mass parts of polycarbonate (A), Preferably 0.3-10 mass parts More preferably, it is 0.5-5 mass parts.

  If content of the polymer (B) in a thermoplastic resin composition is 0.1 mass part or more with respect to 100 mass parts of polycarbonate (A), it is a phase of a polycarbonate (A) and a polymer (C). Capability can be improved, and if it is 15 mass parts or less, it can suppress that the mechanical characteristic of polycarbonate (A) falls.

  Content of the polymer (C) in a thermoplastic resin composition is 5-70 mass parts with respect to 100 mass parts of polycarbonate, Preferably it is 10-50 mass parts, More preferably, it is 15-35 mass parts. is there.

  If the content of the polymer (C) in the thermoplastic resin composition is 5 parts by mass or more with respect to 100 parts by mass of the polycarbonate (A), surface hardness can be improved in the obtained molded product, If it is 70 mass parts or less, it can suppress that the transparency of a polycarbonate (A) falls.

  The thermoplastic resin composition may contain other resins, additives, and the like as necessary within a range not impairing the function of the polymer.

  Examples of such resins include polystyrene resins such as ABS, HIPS, PS, and PAS; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyolefin resins; the above polycarbonate (A), polymer (B), and polymer ( Examples thereof include polymer alloys such as elastomers blended with thermoplastic resins other than C).

  The content of these resins is preferably in a range that does not impair the heat resistance, impact resistance, flame retardancy, etc. inherent to the polycarbonate (A). Specifically, the polycarbonate (A) and the polymer (B). And 100 parts by mass of the total of the polymer (C) and 50 parts by mass or less.

  Examples of additives that may be contained in the thermoplastic resin composition include stabilizers, weathering agents, reinforcing agents, inorganic fillers, impact modifiers, flame retardants, antistatic agents, mold release agents, and dyes. Examples thereof include pigments and fluoroolefins.

  Specifically, talc, mica, calcium carbonate, glass fiber, carbon fiber, potassium titanate fiber, and the like can be used to improve the strength, rigidity, and flame retardancy of the molded product. Furthermore, other engineering plastics such as polyethylene terephthalate for improving chemical resistance, rubbery elastic bodies for improving impact resistance, and the like may be contained.

  Examples of the stabilizer include triphenyl phosphite, tris (nonylphenyl) phosphite, distearyl pentaerythritol diphosphite, diphenyl hydrogen phosphite, irganox 1076 [stearyl-β- (3,5-diphenyl). -Tert-butyl-4-hydroxyphenyl) propionate].

  Examples of the weathering agent include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-amylphenyl) benzotriazole, 2 -(2'-Hydroxy-4'-octoxyphenyl) benzotriazole, 2-hydroxy-4-octoxybenzophenone.

  Manufacture of a thermoplastic resin composition can be based on the method of mixing a polycarbonate (A), a polymer (B), and a polymer (C) in a powder state, or the method of kneading these by heating and melting. .

  As a mixing method, a polycarbonate (A) is prepared by preparing a master batch containing a polymer (B) and a polymer (C) at a high concentration, and then diluted with the polycarbonate (A). ) And a polymer (B), a method of preparing a masterbatch of polycarbonate (A) and polymer (C) and mixing them, or a masterbatch of polymer (B) and polymer (C), A method of mixing this with polycarbonate (A) or the like can be applied.

  In order to prepare a master batch of the polymer (B) and the polymer (C), a method of polymerizing the monomer constituting the polymer (B) in the presence of the polymer (C), or a polymer It can also be based on a method of polymerizing the monomer constituting the polymer (C) in the presence of (B).

  For the mixing, for example, a Henschel mixer, a Banbury mixer, a single screw extruder, a twin screw extruder, two rolls, a kneader, a Brabender, or the like can be used.

  The molded product of the present invention is obtained by molding the thermoplastic resin composition.

  As the molding method, any method such as compression molding, transfer molding, injection molding, blow molding, extrusion molding, laminate molding, and calendering molding can be used.

  The resulting molded article has the properties of polycarbonate such as excellent mechanical strength, heat resistance, electrical properties, dimensional stability, and flame retardancy, and has high surface hardness and excellent transparency.

  The injection-molded article of the present invention is obtained by injection molding the above thermoplastic resin composition.

  As conditions for injection molding, the molding temperature is in the range of 260 to 320 ° C, and the mold temperature is preferably 80 ° C or higher, preferably 100 ° C or higher from the viewpoint of improving the surface hardness.

  Molded products obtained by injection molding have high surface hardness, can be used as molded products without laminating a hard coat layer on the surface, and can be reduced in cost from the viewpoint of simplifying the manufacturing process. .

  Therefore, it can be sufficiently used even in applications that are used outdoors such as automobile headlamps, eyeglass lenses, or seats.

  Hereinafter, although the present invention is explained in full detail using an example, the technical scope of the present invention is not limited to this.

  In the following, “part” and “%” indicate “part by mass” and “% by mass”, respectively.

  Mw of the polymers (B) and (C) was measured under the following conditions. Similarly, the number average molecular weight (hereinafter referred to as “Mn”) was also measured.

Apparatus: HLC-8220GPC manufactured by Tosoh Corporation
Column: Tosoh Co., Ltd. TSKGel SuperHZM-M
(Inner diameter 4.6 mm x length 150 mm) 4 eluents: THF (tetrahydrofuran)
Flow rate: 0.35 ml / min Temperature: 40 ° C
Sample concentration: 0.1%
Sample injection volume: 10 μl
Detector: RI (UV)

[Production Example 1] Production of polymer (B-1) In a separable flask equipped with a thermometer, a cooling tube, a nitrogen introduction tube, and a stirrer, a mixture of 281 parts of deionized water and 1 part of sodium dodecylbenzenesulfonate Was introduced.

  Then, 98 parts of phenyl methacrylate, 2 parts of methyl acrylate, and 0.001 part of n-octyl mercaptan (chain transfer agent) were added.

  After replacing the inside of the container with nitrogen, the temperature was raised to 50 ° C., a mixed solution of 0.4 part of t-butyl hydroperoxide and 9 parts of deionized water was added, and then 0.001 part of ferrous sulfate and ethylenediamine. Radical polymerization was started by adding a mixed solution of disodium tetraacetate 0.003 part, Rongalite 0.2 part, and 9 parts of deionized water, and then held at 60 ° C. for 1 hour to complete the polymerization.

  The obtained latex of the polymer (B-1) was put into 400 parts of a 5% calcium acetate aqueous solution for coagulation and coagulated at 90 ° C.

  The coagulated product was washed with warm water and then dried to obtain a polymer (B-1). Mw of the obtained polymer (B-1) was 1,500,000.

[Production Example 2] Production of polymer (B'-1) A polymer (B'-1) was obtained in the same manner as in Production Example 1 except that methyl methacrylate was used instead of phenyl methacrylate. Mw of the obtained polymer (B′-1) was 1,500,000.

[Production Example 3] Production of polymer (C-1) The following components were charged into a separable flask equipped with a thermometer, a cooling tube, a nitrogen introduction tube, and a stirrer. After replacing the inside of the container with nitrogen, the temperature was raised to 80 ° C.

Deionized water 200 parts Dispersion stabilizer 0.3 part Sodium sulfate 0.5 part 2,2'-azobisisobutyronitrile 0.3 part n-octyl mercaptan 2.5 parts Methyl methacrylate 98 parts Methyl acrylate 2 parts

  Stirring was continued for 4 hours, and the obtained bead polymer (C-1) was washed with water and dried to obtain a polymer (C-1).

  Mw of the obtained polymer (C-1) was 11,000, Mn was 5,000, and molecular weight distribution (Mw / Mn) was 2.2.

[Production Example 4] Production of polymer (C'-1) A polymer (C'-1) was produced in the same manner as in Production Example 3 except that the amount of n-octyl mercaptan used was changed from 2.5 parts to 0.2 parts. C′-1) was obtained.

  Mw of the obtained polymer (C′-1) was 100,000, Mn was 50,000, and the molecular weight distribution (Mw / Mn) was 2.0.

[Examples 1 to 3, Comparative Examples 1 to 5] Thermoplastic resin compositions Polymers obtained in Production Examples 1 to 4 and commercially available polycarbonate (A) (trade name "Iupilon S-2000F", Mitsubishi Engineering Plastics Sv Co., Ltd., Mv: 24,000) are mixed at a mass ratio shown in Table 1, and supplied to a twin-screw extruder (model name “TEX-30α”, manufactured by Nippon Steel) and melted at 280 ° C. The mixture was kneaded to obtain a thermoplastic resin composition.

  In the table, the numerical values in the columns of polycarbonate (A), polymer (B), and polymer (C) indicate parts by mass.

  Using this, tests were conducted as follows for surface hardness, Rockwell hardness, transparency, and impact strength.

[surface hardness]
Using the obtained thermoplastic resin composition, a plate test piece having a thickness of 3 mm was prepared by injection molding at a barrel temperature of 280 ° C. and a mold temperature of 90 ° C., and the measurement was performed according to JIS K5400. Table 1 shows the pencil hardness at which no scratches are observed.

[Rockwell hardness]
Two test pieces were stacked and measured on an M scale according to JIS K7202-2. The results are shown in Table 1.

[transparency]
Using a haze meter HR-100 (manufactured by Murakami Color Research Laboratory Co., Ltd.), the total light transmittance and haze of the test piece were measured according to JIS-K7105. The results are shown in Table 1.

[Impact strength]
Using the obtained thermoplastic resin composition, a test piece having a thickness of 6.4 mm was prepared by injection molding at a barrel temperature of 280 ° C. and a mold temperature of 90 ° C. A notch (notch) was formed in the test piece to prepare a notched Izod impact test piece, and an Izod test was conducted in accordance with ASTM D256. The results are shown in Table 1.

  As is apparent from Table 1, molded articles (Examples 1 to 3) using the thermoplastic resin composition of the present invention have excellent pencil hardness and high transparency.

  Since the thermoplastic resin composition of Comparative Example 1 uses a polymer (B′-1) mainly composed of methyl methacrylate as the polymer (B), the molded product has a slightly inferior pencil hardness. , Transparency is inferior.

  Since the thermoplastic resin composition of Comparative Example 2 does not use the polymer (B), the molded product is slightly inferior in pencil hardness.

  Since the thermoplastic resin composition of Comparative Example 3 uses (C′-1) having a Mw outside the scope of the present invention as the polymer (C), the molded product has pencil hardness and transparency. Both are significantly inferior.

  Since the thermoplastic resin composition of Comparative Example 4 does not use the polymer (C), the molded article has extremely inferior pencil hardness.

  The thermoplastic resin composition of Comparative Example 5 does not use the polymers (B) and (C), and the molded product has extremely inferior pencil hardness.

  The thermoplastic resin composition of the present invention is excellent in surface hardness as compared with polycarbonate and can maintain transparency. Therefore, the thermoplastic resin composition can be used outdoors such as automobile headlamps, eyeglass lenses, or sheets, and a material for optical media. For example, it can be used in a wide range of fields, such as applications that require transparency such as cases, and applications that require color development such as a housing.

Claims (2)

For 100 parts by mass of polycarbonate (A),
0.1 to 15 parts by mass of a polymer (B) containing 50% by mass or more of an aromatic (meth) acrylate unit, and
A thermoplastic resin composition obtained by blending 5 to 70 parts by mass of a polymer (C) having a methyl methacrylate unit of 60% by mass or more and having a mass average molecular weight of 5,000 to 20,000.   An injection-molded article obtained using the thermoplastic resin composition according to claim 1.