JP2004307852A - Resin composition and molded article thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a colorless and transparent resin composition excellent in durability. <P>SOLUTION: The resin composition comprises 0.0005-0.1 pts.wt of a 2-(1-arylalkylidene) acetic ester per 100 pts.wt of at least one resin selected from a methyl methacrylate resin, a styrene resin and a methyl methacrylate-styrene copolymer resin, wherein the acetic ester is expressed, for example, in formula (1) (in the formula X is H, an alkyl group or an alkoxy group, R<SP>1</SP>is an alkyl group.). The molded article of the resin composition is suitable for an optical guide or the like. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a resin composition and a molded product thereof.

Methyl methacrylate resin, styrene resin, and methyl methacrylate-styrene resin are useful as colorless and transparent thermoplastic resins. As a resin having improved durability, a resin composition in which an ultraviolet absorber is blended with these resins is known, and is described in Non-Patent Document 1 [JETI, Vol. 46, No. 5, (issued in 1998), No. 116] Pp. 121 to 121] discloses a resin composition in which a methyl salicylate-based ultraviolet absorber, a cyanoacrylate-based ultraviolet absorber, and a benzotriazole-based ultraviolet absorber are blended as an ultraviolet absorber in a methyl methacrylate resin or a styrene resin. .

JETI, Vol. 46, No. 5, 1998. Pages 116-121.

However, in such a conventional resin composition, the durability is not always sufficient, or if a large amount of an ultraviolet absorber is contained in order to further improve the durability, it may be slightly colored, possibly due to the ultraviolet absorber. There was a problem.

The present inventors have conducted intensive studies to develop a resin composition having excellent durability without impairing the properties of these resins, which are colorless and transparent, and as a result, 2- (1-arylalkylidene) acetates Was found to be able to be made into a resin composition which is colorless and transparent and has excellent durability, and led to the present invention.

That is, the present invention provides 0.0005 to 0.1 parts by mass of 2- (1-aryl) per 100 parts by mass of at least one resin selected from methyl methacrylate resin, styrene resin, and methyl methacrylate-styrene resin. (Alkylidene) acetate A resin composition containing 0.0005 parts by mass or more and 0.1 parts by mass or less of 2- (1-arylalkylidene) acetates per 100 parts by mass of the resin composition containing the esters. To provide.

Further, the present invention also provides a molded article obtained by molding the above resin composition.

The resin composition of the present invention has improved durability without impairing the properties of the colorless and transparent methyl methacrylate resin, styrene resin, and methyl methacrylate-styrene resin.

The resin composition of the present invention contains one or more resins selected from methyl methacrylate resin, styrene resin, and methyl methacrylate-styrene resin, and 2- (1-arylalkylidene) acetic acid esters.

The methyl methacrylate resin is a polymer containing 50% by mass or more of methyl methacrylate units as monomer units, and is substantially a homopolymer of methyl methacrylate, such as polymethyl methacrylate and 50% by mass of methyl methacrylate. Copolymers of the above and 50% by mass or less of an unsaturated monomer copolymerizable therewith are exemplified.

Examples of the unsaturated monomer copolymerizable with methyl methacrylate include, for example, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate. Methacrylates other than methyl methacrylate,
Acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate,
Unsaturated acids such as methacrylic acid and acrylic acid,
Examples thereof include acrylonitrile, methacrylonitrile, maleic anhydride, phenylmaleimide, and cyclohexylmaleimide. If necessary, two or more of these can be used. Such a copolymer may contain a glutaric anhydride unit or a glutarimide unit.

As the unsaturated monomer copolymerizable with the methyl methacrylate is preferably an alkyl acrylate such as methyl acrylate because the molding process is facilitated, and alkyl acrylate is preferably used as the unsaturated monomer. When it is contained, the monomer unit composition in the copolymer preferably ranges from 80% by mass to 99.5% by mass of methyl methacrylate units and from 0.5% by mass to 20% by mass of alkyl acrylate units. It is.

The styrene resin is a polymer containing 50% by mass or more of a styrene unit as a monomer unit, and is substantially a homopolymer of styrene such as styrene or α-methylstyrene. Copolymers of the above and 50% by mass or less of an unsaturated monomer copolymerizable therewith are exemplified. Examples of the unsaturated monomer copolymerizable with styrenes include the same as those described above in the methyl methacrylate resin.

The methyl methacrylate-styrene resin is a polymer containing a methyl methacrylate unit and a styrene unit as monomer units, and usually has a methyl methacrylate unit of 10% by mass to 90% by mass and a styrene unit of 90% by mass. % By mass, preferably 20% by mass to 80% by mass of methyl methacrylate units, 80% by mass to 20% by mass of styrene units, and more preferably 60% by mass of methyl methacrylate units. 80 mass%, and the styrene unit is 40 mass% to 20 mass%.

Styrene resin and methyl methacrylate-styrene resin are preferably used because they hardly absorb water.

In the resin composition of the present invention, these methyl methacrylate resin, styrene resin and methyl methacrylate-styrene resin may be used alone or in combination of two or more.

The resin composition of the present invention contains 2- (1-arylalkylidene) acetic acid esters in at least one resin selected from the above-mentioned methyl methacrylate resin, styrene resin and methyl methacrylate-styrene resin. The content of 2- (1-arylalkylidene) acetates is 0.0005 parts by mass or more, preferably 0.003 parts by mass or more, and more preferably 0.005 parts by mass, per 100 parts by mass of the resin from the viewpoint of durability. Parts or more. Further, from the viewpoint of transparency, the amount is 0.1 part by mass or less, preferably 0.05 part by mass or less, more preferably 0.03 part by mass or less.

〔式中、Ｘは水素原子、アルキル基またはアルコキシル基を示し、Ｒ¹はアルキル基を示す。〕
で示される化合物であることが好ましい。 From the viewpoint of durability, 2- (1-arylalkylidene) acetic acid esters represented by the formula (1)

[In the formula, X represents a hydrogen atom, an alkyl group or an alkoxyl group, and R ¹ represents an alkyl group. ]
It is preferable that the compound is represented by

The alkoxyl group in the substituent X may be linear or branched, and examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group and an isobutoxy group. , Sec-butoxy group, tert-butoxy group, n-pentoxy group and the like, and an alkoxyl group having about 1 to 6 carbon atoms, preferably an alkoxyl group having about 1 to 4 carbon atoms. The alkyl group may be linear or branched, and may be, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a sec-butyl group. Tert-butyl group, n-pentyl group, n-hexyl group and other alkyl groups having about 1 to 6 carbon atoms, preferably an alkyl group having about 1 to 4 carbon atoms, more preferably a methoxy group. is there. The substituent X is preferably an alkoxyl group.

Examples of the alkyl group for the substituent R ¹ include an alkyl group usually having about 1 to 10 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a sec- Butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decanyl group, 1-methylpentyl group, 1-ethylpentyl group, Examples thereof include an alkyl group having about 1 to 10 carbon atoms such as a 1-methylhexyl group and a 2-ethylhexyl group, and a methyl group and a 2-ethylhexyl group are preferable.

The resin composition of the present invention may contain hindered amines. Hindered amines include, for example, compounds having a 2,2,6,6-tetraalkylpiperidine skeleton.

Examples of such hindered amines include a polycondensate of dimethyl succinate and 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, poly ((6- (1 , 1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl) ((2,2,6,6-tetramethyl-4-piperidyl) imino) hexamethylene (( Bis (1,2,2,6,6-tetramethyl-4-piperidyl) imino)), 2- (2,3-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate , 2,6,6-pentamethyl-4-piperidyl), bis (1,2,2,6,2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate) 6-pentamethyl-4-piperidyl), N N'-bis (3-aminopropyl) ethylenediamine and 2,4-bis (N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino) -6-chloro-1, Condensates with 3,5-triazine, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) succinate, etc. No.

〔式中、Ｙは水素原子、炭素数１〜２０のアルキル基、全炭素数２〜２０のカルボキシアルキル基、全炭素数２〜２５のアルコキシアルキル基または全炭素数３〜２５のアルコキシカルボニルアルキル基を表わす。〕
で示される化合物も挙げられる。 Equation (2)

Wherein Y is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a carboxyalkyl group having 2 to 20 carbon atoms, an alkoxyalkyl group having 2 to 25 carbon atoms, or an alkoxycarbonylalkyl having 3 to 25 carbon atoms. Represents a group. ]
The compound shown by these is also mentioned.

The alkyl group in the substituent Y may be linear or branched. The alkyl group constituting the carboxyalkyl group may be linear or branched. Each of the two alkyl groups constituting the alkoxyalkyl may be linear or branched. As the substituent Y, a hydrogen atom or an alkoxycarbonylalkyl group having 5 to 24 carbon atoms is preferable, and a hydrogen atom or an alkoxycarbonylethyl group is more preferable. Examples of the alkoxycarbonylethyl group include a dodecyloxycarbonylethyl group, a tetradecyloxycarbonylethyl group, a hexadecyloxycarbonylethyl group, an octadecyloxycarbonylethyl group, and the like.

When a hindered amine is contained, its content is usually at least 0.0001 part by mass, preferably at least 0.001 part by mass, and more preferably at least 0.003 part by mass per 100 parts by mass of the resin. It is usually at most 0.1 part by mass, preferably at most 0.05 part by mass, more preferably at most 0.03 part by mass, and usually at most 1 part by mass based on 2- (1-arylalkylidene) acetic acid esters. And preferably 0.1 to 0.8 times by mass.

The resin composition of the present invention may contain various additives. Examples of such additives include siloxane-based crosslinked resin particles, styrene-based crosslinked resin particles, acrylic-based crosslinked resin particles, glass particles, light diffusing agents such as talc, calcium carbonate, and barium sulfate, and matting agents. Antistatic agents such as sodium alkyl sulfonates, sodium alkyl sulfates, monoglycerides stearates, and polyetheresteramides are also included. Antioxidants such as hindered phenols are also included. Flame retardants such as phosphates are also included. Lubricants such as palmitic acid and stearyl alcohol are also included. These additives may be used alone or in combination of two or more.

The resin composition of the present invention can be produced, for example, by a method of melt-kneading a resin with 2- (1-arylalkylidene) acetic acid esters. When the resin composition of the present invention contains hindered amines and additives, the above resin may be melt-kneaded with 2- (1-arylalkylidene) acetic acid esters and hindered amines. For melt kneading, for example, an extruder such as a single screw extruder or a twin screw extruder, or a kneader may be used.

It can also be produced by a method in which the above-mentioned monomer for producing the above-mentioned resin is mixed with 2- (1-arylalkylidene) acetic acid esters and then polymerized. In order to produce a methacrylic resin composition containing hindered amines and additives, a monomer may be mixed with 2- (1-arylalkylidene) acetic acid esters, hindered amines and additives, and then polymerized. . The polymerization may be carried out batchwise or continuously. By polymerizing in a cell, a molded article of the resin composition can be obtained.

In order to mold the resin composition of the present invention, the resin composition may be formed into a plate by extrusion molding through a T-die or a roll unit, or may be formed into a plate or wedge by injection molding or press molding. . Alternatively, a composition formed into a plate may be obtained by cast polymerization.

Since the resin composition of the present invention is colorless and transparent and has sufficient durability, a molded article formed from the resin composition is suitably used, for example, as an optical component, and particularly preferably used as a light guide. Such a light guide is suitably used for a backlight of a liquid crystal display or the like having a screen size of 14 inches (35.6 cm diagonal) or more, preferably 20 inches (50.8 cm diagonal) or more.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1
100 parts by mass of methyl methacrylate resin [a copolymer of 96% by mass of methyl methacrylate units and 4% by mass of methyl acrylate units, pellets] and 2-ethylhexyl 2- (paramethoxybenzylidene) acetate [in the formula (1) 0.003 parts by mass of a compound wherein the substituent X corresponds to a methoxy group and R ¹ corresponds to a 2-ethylhexyl group) at room temperature, and then the mixture is charged into a single screw extruder [screw diameter 40 mm, with vent]. It is melt-kneaded, extruded from a T-die (lip width 250 mm, lip interval 6 mm) at an extrusion temperature of 250 ° C., and cooled while passing between three polishing rolls to form a continuous 3.5 mm thick, 22 cm wide. Into a sheet. The obtained sheet [thickness (t) 3.5 mm] was cut into a strip having a width (W) of 7 cm and a length (L) of 30 cm, and the end face was mirror-polished to obtain a test piece.

As shown in FIG. 1, when white light (2) is incident in the long side direction from one of the short side end faces (11) of the test piece (1), the inside of the test piece (1) is moved in the long side direction. The light transmittance (T ₄₀₀ ) at a wavelength of 400 nm and the average transmittance (Tt) at a wavelength of 380 nm to 780 nm for the transmitted light (3) transmitted through the other short-side end surface (12). As a result, T ₄₀₀ was 72%, T _t was 82%, and the ratio of T ₄₀₀ to T _t (T ₄₀₀ / T _t ) was 0.88. When this transmitted light was visually observed, it was almost colorless.

After irradiating the test piece obtained above with ultraviolet rays at 60 ° C. for 8 days, the same evaluation as above was carried out. T ₄₀₀ was 78%, T _t was 82%, and T ₄₀₀ / T _t was 0.1%. 95. When the transmitted light was visually observed, it was almost colorless.

Comparative Example 1
A test piece was obtained and evaluated in the same manner as in Example 1 except that 2-ethylhexyl 2- (paramethoxybenzylidene) acetate was not used, and T ₄₀₀ was 81%, T _t was 84%, and T _{400 was obtained.} / _Tt was 0.96. When the transmitted light was visually observed, it was almost colorless.

When the test piece obtained above was irradiated with ultraviolet rays in the same manner as in Example 1, _T400 was 0%, _Tt was 37%, and _T400 / _Tt was 0. When the transmitted light was visually observed, it was yellowish.

Comparative Example 2
The same operation as in Example 1 was carried out except that 0.01 parts by mass of 2- (2-hydroxy-5-methylphenyl) -2H-benzotriazole was used instead of 2-ethylhexyl 2- (paramethoxybenzylidene) acetate. When a test piece was obtained and evaluated, T ₄₀₀ was 39%, T _t was 78%, and T ₄₀₀ / T _t was 0.50. This test piece has a smaller T ₄₀₀ / T _t than the test piece obtained in Example 1. Further, when the transmitted light was visually observed, the transmitted light was slightly yellowish.

Comparative Example 3
A test piece was obtained and evaluated in the same manner as in Example 1, except that 0.01 parts by mass of 2,4-dihydroxybenzophenone was used instead of 2-ethylhexyl 2- (paramethoxybenzylidene) acetate. ₄₀₀ 36%, Tt is 78%, _{T 400} / T _t was 0.46. This test piece has a smaller T ₄₀₀ / T _t than the test piece obtained in Example 1. Further, when the transmitted light was visually observed, the transmitted light was slightly yellowish.

Comparative Example 4
Instead of 2-ethylhexyl 2- (paramethoxybenzylidene) acetate, 2,2′-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6-((2H-benzotriazol-2-yl) ) Phenol) A test piece was obtained and evaluated in the same manner as in Example 1 except that 0.01 part by mass was used. T ₄₀₀ was 3%, T _t was 76%, and T ₄₀₀ / T _{t was obtained.} This test piece had a smaller T ₄₀₀ / T _t than the test piece obtained in Example 1. When the transmitted light was visually observed, the test piece was yellowish. .

Example 2
0.002 parts by mass of 2,2′-azobisisobutyronitrile was mixed with 100 parts by mass of methyl methacrylate, and partially polymerized at 80 ° C. to obtain a partial polymer having a polymer content of 5% by mass. To 100 parts by mass of this partial polymer, 2-ethylhexyl 2- (paramethoxybenzylidene) acetate (a compound in which the substituent X in the general formula (1) corresponds to a methoxy group and R ¹ corresponds to a 2-ethylhexyl group) 0 0.01 parts by mass and 0.08 parts by mass of 2,2′-azobisisobutyronitrile were added, and the mixture was devolatilized under reduced pressure (absolute pressure: 87 kPa) for 30 minutes. Next, the mixture was poured into a polymerization cell composed of two pieces of tempered glass of 30 cm square and a gasket made of vinyl chloride, and the polymerization cell was heated to 72 ° C. and maintained for 3 hours, and then heated to 120 ° C. and maintained for 1 hour. Polymerization was performed to obtain an acrylic resin composition sheet having a thickness of 2 mm.

This sheet is cut out into 7 cm squares, and the spectral transmittance in the thickness direction (2 mm) is measured. The light transmittance (T400) at a wavelength of 400 nm and the wavelength of the transmitted light emitted from the incident surface to the opposite surface are measured. was determined average transmittance in the range of 380nm~780nm the (Tt), T ₄₀₀ 92%, the ratio of the Tt93%, T ₄₀₀ and _{T t (T 400 / T t} ) was 0.99 . After irradiating the test piece obtained above with ultraviolet rays at 60 ° C. for 8 days, the same evaluation as above was carried out. As a result, T ₄₀₀ was 80%, T _t was 90%, and T ₄₀₀ / T _t was 0.2%. 89.

Example 3
A 2-mm-thick sheet was obtained in the same manner as in Example 2, except that the amount of 2-ethylhexyl 2- (paramethoxybenzylidene) acetate used was changed to 0.02 parts by mass. T ₄₀₀ of the obtained test piece was 92%, T _{t was} 93%, and T ₄₀₀ / T _t was 0.99. Further, as a result of ultraviolet irradiation test in the same manner as in Example 2, T ₄₀₀ 82% of the test piece, the _{T t 91%, T 400 /} T t was 0.91.

Example 4
A mixture of 49 parts by mass of methyl methacrylate, 33 parts by mass of styrene, and 18 parts by mass of a methyl methacrylate-styrene copolymer [60% by mass of methyl methacrylate units, 40% by mass of styrene units] (total 100 parts by mass) was used. 0.02 parts by mass of butyl peroxyisopropyl carbonate and 0.02 parts by mass of 2-ethylhexyl 2- (paramethoxybenzylidene) acetate were added, and the mixture was devolatilized under reduced pressure (absolute pressure: 87 KPa) for 30 minutes to obtain a mixture. This mixture was injected into a polymerization cell composed of two pieces of 30 cm square tempered glass and a gasket made of vinyl chloride. Thereafter, the same operation as in Example 2 was performed to obtain an acrylic resin composition sheet having a thickness of 2 mm.

The sheet was operated in the same manner as in Example 2 to determine the light transmittance (T ₄₀₀ ) at a wavelength of 400 nm in the thickness direction (2 mm) and the average transmittance (T _t ) within a range of 380 nm to 780 nm. where, T ₄₀₀ 91%, is T _t 92% ratio of T400 and Tt _{(T 400} / T _t) was 0.99. After irradiating the test piece obtained above with ultraviolet rays at 60 ° C. for 8 days, the same evaluation as above was carried out. As a result, T ₄₀₀ was 61%, T _t was 86%, and T ₄₀₀ / T _t was 0.1%. 71.

Example 5
0.02 parts by mass of bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate ["Tinuvin 770" manufactured by Ciba Geigy] was further added to the mixture obtained in the same manner as in Example 4. Using the same procedure as in Example 4, an acrylic resin composition sheet was obtained. T ₄₀₀ of the test piece of the obtained sheet was 91%, T _{t was} 92%, and T ₄₀₀ / T _t was 0.99. Further, as a result of ultraviolet irradiation test in the same manner as in Example 2, T ₄₀₀ 72% of the test piece, the _{T t 88%, T 400 /} T t was 0.82.

Example 6
16 parts by mass of methyl methacrylate, 66 parts by mass of styrene, and 18 parts by mass of a methyl methacrylate-styrene copolymer (20% by mass of methyl methacrylate unit, 80% by mass of styrene unit) were mixed (total 100 parts by mass), and t- 0.02 parts by mass of butyl peroxyisopropyl carbonate and 0.02 parts by mass of 2-ethylhexyl 2- (paramethoxybenzylidene) acetate were added, and devolatilized under reduced pressure (absolute pressure: 87 kPa) for 30 minutes to obtain a mixture. This mixture was injected into a polymerization cell composed of two pieces of 30 cm square tempered glass and a gasket made of vinyl chloride. Thereafter, the same operation as in Example 2 was performed to obtain an acrylic resin composition sheet having a thickness of 2 mm.

The sheet was operated in the same manner as in Example 2 to determine the light transmittance (T ₄₀₀ ) at a wavelength of 400 nm in the thickness direction (2 mm) and the average transmittance (T _t ) within a range of 380 nm to 780 nm. where, T ₄₀₀ 89%, is T _t 90% ratio of T ₄₀₀ and _{T t (T 400 / T t} ) was 0.99. After irradiating the test piece obtained above with ultraviolet rays at 60 ° C. for 8 days, the same evaluation as above was carried out. As a result, T ₄₀₀ was 49%, T _t was 83%, and T ₄₀₀ / T _t was 0.1%. 59.

Example 7
0.02 parts by mass of bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate [“Tinuvin 770” manufactured by Ciba Geigy] was further added to the mixture obtained in the same manner as in Example 6. Using the same procedure as in Example 4, an acrylic resin composition sheet was obtained. T ₄₀₀ is 89% of the test piece of the _{sheet, T t 90%, T 400} / T t was 0.99. Further, as a result of ultraviolet irradiation test in the same manner as in Example 2, T ₄₀₀ 61% of the test piece, the _{T t 86%, T 400 /} T t was 0.71.

Comparative Example 5
A mixture was obtained in the same manner as in Example 6, except that 2-ethylhexyl 2- (paramethoxybenzylidene) acetate was not used, and an acrylic resin composition sheet was obtained in the same manner as in Example 4. The test piece obtained from this sheet had a _T400 of 89%, a _{Tt of} 90%, and a _T400 / _Tt of 0.99. Further, as a result of ultraviolet irradiation test in the same manner as in Example 2, T ₄₀₀ is 10% of the specimens, the _{T t 73%, T 400 /} T t was 0.14.

It is a typical perspective view for explaining the evaluation method of the test piece in an example.

Explanation of reference numerals

1: Test piece
11: Short side end face 12: Short side end face 2: White light 3: Transmitted light L: Length W: Width t: Thickness

Claims (4)

0.0005 to 0.1 parts by mass of 2- (1-arylalkylidene) acetic acid esters per 100 parts by mass of at least one resin selected from methyl methacrylate resin, styrene resin and methyl methacrylate-styrene resin The resin composition which is mix | blended. 2- (1-arylalkylidene) acetic acid esters represented by formula (1)

[In the formula, X represents a hydrogen atom, an alkyl group or an alkoxyl group, and R ¹ represents an alkyl group. ]
The resin composition according to claim 1, which is a compound represented by the formula: A molded article obtained by molding the resin composition according to claim 1. The molded article according to claim 3, which is a light guide.

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