JP2006273883A - Imide resin, optical resin composition by using the same and molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin excellent in transparency, heat resistance and further molding processability. <P>SOLUTION: This imide resin is characterized by having ≥0.3 mmol/g residual carboxyl group in the resin and also ≤1,000 ppm concentration of residual esterifying agent in the resin. Thereby, it is possible to reduce bad conditions such as foaming, etc., generated on molding the imide resin and obtain the molded article having excellent appearance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imide resin having improved moldability, an optical resin composition containing the imide resin, and a molded body.

  In recent years, electronic devices have become more and more miniaturized, and have been used for various purposes by taking advantage of light weight and compactness, as represented by notebook personal computers, mobile phones, and portable information terminals. On the other hand, in the field of flat panel displays such as liquid crystal displays and plasma displays, it is also required to suppress an increase in weight due to an increase in screen size.

  In applications that require transparency, such as electronic devices as described above, there is an increasing trend to replace members that have conventionally used glass with resins having good transparency.

  Various transparent resins such as poly (methyl methacrylate) have excellent moldability and workability compared to glass, are hard to break, and are lightweight and inexpensive. Development has been studied and some have been put to practical use.

  With the expansion of applications such as automotive headlamp covers and liquid crystal display members, transparent resins are required to have heat resistance in addition to transparency. Polymethyl methacrylate and polystyrene have good transparency and are relatively inexpensive, but have low heat resistance, so the application range is limited in such applications.

  Therefore, as a method for improving the heat resistance of polymethyl methacrylate, a technique of improving the heat resistance by treating a polyamine methacrylate with a primary amine and imidizing is known (for example, see Patent Document 1). . Imide resins obtained by treating primary amines with these polymethylmethacrylates have good transparency and heat resistance, and may be used effectively in various applications, such as optical applications.

  However, imide resins obtained by treating primary amines with polymethyl methacrylate and the like often generate carboxyl groups and acid anhydride groups in the resin side chain during the imidation reaction. There was a case where the compatibility of was deteriorated. Therefore, a technique for converting a carboxyl group or an acid anhydride group contained in an imide polymer into an ester group or the like with a reagent such as dimethyl carbonate has been found (for example, see Patent Document 2).

However, even the imide resin thus improved has a problem in that foaming or the like occurs when heated to a flowable temperature for processing, and a molded article having a good appearance cannot be obtained.
U.S. Pat. No. 4,246,374 U.S. Pat. No. 4,727,117

  Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a transparent imide resin having improved moldability and superior heat resistance compared to polymethyl methacrylate.

  As a result of intensive studies in view of the above problems, the present inventors have found that the ratio of carboxyl groups remaining in the resin is 0.3 mmol / g or less, and the concentration of the esterifying agent remaining in the resin is 1000 ppm or less. An imide resin is provided. According to this, problems such as foaming that occur when molding an imide resin are reduced, and a molded article having an excellent appearance can be obtained.

  According to the above configuration, it is possible to provide a transparent imide resin having improved moldability and superior heat resistance compared to polymethyl methacrylate, and polymethyl methacrylate can replace glass due to the conventional heat resistance problem. There is a possibility that it can be developed into a molded body that is not present, which is useful.

  The present invention relates to an imide resin characterized in that the proportion of carboxyl groups remaining in the resin is 0.3 mmol / g or less and the concentration of the esterifying agent remaining in the resin is 1000 ppm or less. . Further, the imide resin is preferably an imide resin containing a repeating unit represented by the following general formulas (1) and (2), and further contains a repeating unit represented by the general formula (3). An imide resin is preferred.

（ここで、Ｒ¹およびＲ²は、それぞれ独立に、水素または炭素数１〜８のアルキル基を示し、Ｒ³は、炭素数１〜１８のアルキル基、炭素数３〜１２のシクロアルキル基、または炭素数６〜１０のアリール基を示す。）

(Here, R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 18 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)

（ここで、Ｒ⁴およびＲ⁵は、それぞれ独立に、水素または炭素数１〜８のアルキル基を示し、Ｒ⁶は、炭素数１〜１８のアルキル基、炭素数３〜１２のシクロアルキル基、または炭素数６〜１０のアリール基を示す。）

(Here, R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ represents an alkyl group having 1 to 18 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)

（ここで、Ｒ⁷は、水素または炭素数１〜８のアルキル基を示し、Ｒ⁸は、炭素数６〜１０のアリール基を示す。）
本発明のイミド樹脂は、樹脂中に残存するカルボキシル基の割合が０．３ｍｍｏｌ／ｇ以下であることが必要である。更に好ましくは０．２ｍｍｏｌ／ｇ以下、より好ましくは０．１ｍｍｏｌ／ｇ以下とすることが望ましい。樹脂中に残存するカルボキシル基の割合が、０．３ｍｍｏｌ／ｇを越えると、成形加工性が低下し好ましくない。ポリメチルメタクリレート等に一級アミンを処理してイミド樹脂を得た場合には、カルボキシル基は、主にイミド樹脂側鎖に位置しているものと考えられる。本発明者の推定によれば、この様なカルボキシル基は、樹脂が流動する温度（例えば、２６０℃）等まで加熱した場合に、隣接するエステル基との閉環反応を生じ、一級アルコール類を発生させ、成形加工性を低下させるものと考えられる。

(Here, R ⁷ represents hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁸ represents an aryl group having 6 to 10 carbon atoms.)
In the imide resin of the present invention, the proportion of carboxyl groups remaining in the resin needs to be 0.3 mmol / g or less. More preferably, it is 0.2 mmol / g or less, and more preferably 0.1 mmol / g or less. When the ratio of the carboxyl group remaining in the resin exceeds 0.3 mmol / g, the moldability is undesirably lowered. When a primary amine is treated with polymethyl methacrylate or the like to obtain an imide resin, the carboxyl group is considered to be mainly located in the side chain of the imide resin. According to the estimation of the present inventor, such a carboxyl group causes a ring-closing reaction with an adjacent ester group when heated to a temperature at which the resin flows (for example, 260 ° C.), etc., and generates primary alcohols. This is considered to reduce the moldability.

  In addition, as a method of reducing the ratio of the carboxyl group remaining in the resin, there is a method of adding an esterifying agent and reacting with the carboxyl group in the imide resin, for example, converting to a functional group that does not generate primary alcohols. Available. Here, the functional group that does not generate primary alcohols is not particularly limited, and examples thereof include an ester group and an acid anhydride group.

  On the other hand, the imide resin of the present invention requires that the concentration of the esterifying agent remaining in the resin be 1000 ppm or less. Furthermore, 500 ppm or less is more preferable. If the concentration of the esterifying agent exceeds 1000 ppm, molding processability is lowered, which is not preferable.

  Hereinafter, the molecular structure of the preferred imide resin of the present invention or the production method thereof will be described. The present invention is not limited to this. The first structural unit constituting the preferred imide resin of the present invention is represented by the following general formula (1) and is generally called a glutarimide unit (hereinafter referred to as general formula (1)). Sometimes abbreviated as glutarimide unit).

（ここで、Ｒ¹およびＲ²は、それぞれ独立に、水素または炭素数１〜８のアルキル基を示し、Ｒ³は、炭素数１〜１８のアルキル基、炭素数３〜１２のシクロアルキル基、または炭素数６〜１０のアリール基を示す。）
好ましいグルタルイミド単位としては、Ｒ¹、Ｒ²が水素またはメチル基であり、Ｒ³が水素、メチル基、ブチル基、またはシクロヘキシル基である。Ｒ¹がメチル基であり、Ｒ²が水素であり、Ｒ³がメチル基である場合が、特に好ましい。

(Here, R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 18 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)
As a preferred glutarimide unit, R ¹ and R ² are hydrogen or a methyl group, and R ³ is hydrogen, a methyl group, a butyl group, or a cyclohexyl group. The case where R ¹ is a methyl group, R ² is hydrogen, and R ³ is a methyl group is particularly preferred.

The glutarimide unit may be a single type or may include a plurality of types in which R ¹ , R ² , and R ³ are different.

  The glutarimide unit can be formed by imidizing the second structural unit described below. In addition, acid anhydrides such as maleic anhydride or half esters of these and linear or branched alcohols having 1 to 20 carbon atoms; acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, Α, β-ethylenically unsaturated carboxylic acids such as crotonic acid, fumaric acid, and citraconic acid can also be imidized and can be used to form glutarimide units.

  The second structural unit constituting the preferred imide resin of the present invention is represented by the following general formula (2), and is generally often referred to as a (meth) acrylic acid ester unit (hereinafter referred to as general). (Formula (2) may be abbreviated as a (meth) acrylic acid ester unit).

（ここで、Ｒ⁴およびＲ⁵は、それぞれ独立に、水素または炭素数１〜８のアルキル基を示し、Ｒ⁶は、炭素数１〜１８のアルキル基、炭素数３〜１２のシクロアルキル基、または炭素数６〜１０のアリール基を示す。）
本発明の好ましいイミド樹脂に必要に応じて含有させる第三の構成単位は、下記一般式（３）で表されるものであり、一般的には芳香族ビニル単位と呼ばれることが多い（以下、一般式（３）を芳香族ビニル単位と省略して示すことがある。）

(Here, R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ represents an alkyl group having 1 to 18 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)
The third constitutional unit contained in the preferred imide resin of the present invention as required is represented by the following general formula (3), and is generally called an aromatic vinyl unit (hereinafter referred to as “aromatic vinyl unit”). (General formula (3) may be abbreviated as an aromatic vinyl unit.)

（ここで、Ｒ⁷は、水素または炭素数１〜８のアルキル基を示し、Ｒ⁸は、炭素数６〜１０のアリール基を示す。）
好ましい芳香族ビニル構成単位としては、スチレン、α−メチルスチレン等が挙げられる。これらの中でスチレンが特に好ましい。

(Here, R ⁷ represents hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁸ represents an aryl group having 6 to 10 carbon atoms.)
Preferred aromatic vinyl structural units include styrene, α-methylstyrene, and the like. Of these, styrene is particularly preferred.

These third structural units may be of a single type or may include a plurality of types in which R ⁷ and R ⁸ are different.

  The content of the glutarimide unit represented by the general formula (1) in the imide resin of the present invention depends on, for example, the structure of R3, but is preferably 10% by weight or more of the imide resin. The preferred content of glutarimide units is 15 to 90% by weight, more preferably 20 to 80% by weight. When the ratio of a glutarimide unit is smaller than this range, the heat resistance of the imide resin obtained may be insufficient, or transparency may be impaired. In addition, if it exceeds this range, heat resistance and melt viscosity are unnecessarily increased and molding processability is deteriorated, and the mechanical strength of the obtained molded article becomes extremely fragile, and transparency may be impaired. .

  The content of the aromatic vinyl unit represented by the general formula (3) in the imidized resin is preferably 10% by weight or more based on the total repeating unit of the imide resin. The preferable content of the aromatic vinyl unit is 10 to 40% by weight, more preferably 15 to 30% by weight, and still more preferably 15 to 25% by weight. When the aromatic vinyl unit is larger than this range, the resulting imide resin has insufficient heat resistance. If it is smaller than this range, the mechanical strength of the resulting molded product may be lowered.

  By adjusting the proportions of the general formulas (1), (2), and (3), various required physical properties can be adjusted. For example, when the imide resin of the present invention is first formed by polymerizing a (meth) acrylic ester-aromatic vinyl copolymer such as methyl methacrylate-styrene copolymer, for example, (meth) acrylic acid The ratio of the general formula (3) is determined by adjusting the polymerization ratio of the ester and the aromatic vinyl (the ratio of the general formula (3) can be set to 0), and further, an imidizing agent is added during post-imidation By adjusting the ratio, the ratios of the general formulas (1) and (2) can be further adjusted.

  If necessary, the imide resin of the present invention may further be copolymerized with a fourth structural unit. A constitution obtained by copolymerizing a nitrile monomer such as acrylonitrile and methacrylonitrile, and a maleimide monomer such as maleimide, N-methylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide as the fourth structural unit Units can be used. These may be directly copolymerized in the thermoplastic resin, or may be graft copolymerized.

  The imide resin of the present invention can be suitably produced by the following method.

  First, (meth) acrylic acid ester-aromatic vinyl copolymer such as methyl methacrylate-styrene copolymer comprising the repeating unit represented by the general formula (2) and the repeating unit represented by the general formula (3). Or (meth) acrylic acid ester polymer such as methyl methacrylate polymer composed of a repeating unit represented by the general formula (2) as a main raw material, and a resin treated with an imidizing agent such as ammonia or a substituted amine (Hereinafter, it may be called the imide resin intermediate 1).

  This imide resin intermediate 1 is treated with an esterifying agent, and if necessary, is subjected to heat treatment or the like, so that the ratio of carboxyl groups remaining in the resin is 0.3 mmol / g or less (imide resin intermediate 2). be able to.

  Furthermore, the imide resin intermediate 2 can be obtained by reducing the esterification agent contained in the resin by 1000 vol.

  The production method is not particularly limited as long as the imide resin of the present invention is obtained other than the production method as described above.

  Hereinafter, each component used for each process shown above is demonstrated.

  The imidizing agent of the present invention is not particularly limited as long as it can generate the glutarimide unit represented by the general formula (1). For example, methylamine, ethylamine, n-propylamine, i-propylamine, n -Fatty substances such as aliphatic hydrocarbon group-containing amines such as butylamine, i-butylamine, tert-butylamine, n-hexylamine, aromatic hydrocarbon group-containing amines such as aniline, benzylamine, toluidine, and trichloroaniline, cyclohexylamine, etc. Examples include cyclic hydrocarbon group-containing amines. In addition, urea compounds that generate these amines by heating, such as urea, 1,3-dimethylurea, 1,3-diethylurea, and 1,3-dipropylurea can also be used. Among these imidizing agents, methylamine, ammonia, and cyclohexylamine are preferable from the viewpoint of cost and physical properties, and methylamine is particularly preferable.

  The amount of the imidizing agent added is determined by the imidization rate for expressing necessary physical properties.

  When imidizing with an imidizing agent, generally used catalysts, antioxidants, heat stabilizers, plasticizers, lubricants, ultraviolet absorbers, antistatic agents, coloring agents, antishrinking agents and the like are used for the purpose of the present invention. You may add in the range which is not impaired.

  On the other hand, examples of the esterifying agent include dimethyl carbonate, 2,2-dimethoxypropane, dimethyl sulfoxide, triethyl orthoformate, trimethyl orthoacetate, trimethyl orthoformate, diphenyl carbonate, dimethyl sulfate, methyl toluene sulfonate, methyl trifluoro. Methyl sulfonate, methyl acetate, methanol, ethanol, methyl isocyanate, p-chlorophenyl isocyanate, dimethylcarbodiimide, dimethyl-t-butylsilyl chloride, isopropenyl acetate, dimethylurea, tetramethylammonium hydroxide, dimethyldiethoxysilane, tetra-N -Butoxysilane, dimethyl (trimethylsilane) phosphite, trimethylphosphine Ito, trimethyl phosphate, tricresyl phosphate, diazomethane, ethylene oxide, propylene oxide, cyclohexene oxide, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and benzyl glycidyl ether.

  The addition amount of the esterifying agent is not particularly limited as long as the carboxyl group of the imide resin intermediate 1 can be 0.3 mmol / g or less, but is preferably 1 part by weight to 100 parts by weight, and 3 parts by weight to 50 parts by weight. Is more preferable. When the esterifying agent is larger than this range, a large amount of the esterifying agent may remain in the obtained resin or a side reaction may proceed. On the other hand, when the esterifying agent is smaller than this range, the carboxyl group is reduced to 0.3 mmol / g or less is difficult.

  When the imide resin intermediate 1 is treated with an esterifying agent and heat-treated so that the ratio of carboxyl groups remaining in the resin is 0.3 mmol / g or less, generally used catalysts, antioxidants, heat Stabilizers, plasticizers, lubricants, ultraviolet absorbers, antistatic agents, colorants, antishrink agents, and the like may be added as long as the object of the present invention is not impaired.

  In order to obtain the imide resin intermediate 1, the imide resin intermediate 2 and the imide resin of the present invention, an extruder or the like may be used, or a batch type reaction vessel (pressure vessel) may be used.

  When the method for producing an imide resin of the present invention is carried out with an extruder, various extruders can be used. For example, a single screw extruder, a twin screw extruder, a multi-screw extruder, or the like can be used. In particular, a twin screw extruder is preferable as an extruder that can promote mixing of an imidizing agent or an esterifying agent with a raw material polymer. There are non-mesh type co-rotating type, meshing type co-rotating type, non-meshing type bi-directional rotating type, meshing type bi-directional rotating type, etc. The mesh type co-rotating type is preferable because high speed rotation is possible and mixing of the imidizing agent or esterifying agent with the raw material polymer can be promoted. These extruders may be used alone or connected in series.

  The extruder is preferably equipped with a vent port that can be reduced to atmospheric pressure or lower in order to remove unreacted imidizing agent or by-products such as primary alcohols and monomers. Furthermore, in order to reduce the imidizing agent contained in the obtained imide resin to 1000 ppm or less, it is preferable to perform devolatilization with an extruder equipped with a vent port capable of depressurizing the imide resin to atmospheric pressure or less.

  In order to obtain the imide resin intermediate 1 and the imide resin intermediate 2 of the present invention, the reaction temperature is 150 in order to proceed with imidization or carboxyl group reduction and to suppress the decomposition and coloring of the resin due to excessive thermal history. It is carried out in the range of ~ 400 ° C. 180-320 degreeC is preferable, Furthermore, 200-280 degreeC is preferable.

  In order to obtain the imide resin of the present invention, the temperature of the extruder barrel is in the range of 150 to 400 ° C. in order to advance the removal of the esterifying agent and to suppress the decomposition and coloring of the resin due to excessive heat history. . 180-320 degreeC is preferable, Furthermore, 200-280 degreeC is preferable.

  Instead of the extruder, a high-viscosity reactor such as a horizontal biaxial reactor such as Violac manufactured by Sumitomo Heavy Industries, Ltd. or a vertical biaxial agitation tank such as Super Blend can be suitably used.

  When the production method of the imide resin of the present invention is carried out in a batch-type reaction vessel (pressure vessel), the raw material polymer can be melted by heating and stirred, and the structure is particularly limited so long as it can add an imidizing agent or an esterifying agent. However, the viscosity of the polymer may increase with the progress of the reaction, and those with good stirring efficiency are preferred. For example, Sumitomo Heavy Industries Co., Ltd. agitation tank Max blend etc. can be illustrated.

  (Meth) acrylic acid ester-aromatic vinyl copolymer such as methyl methacrylate-styrene copolymer comprising the repeating unit represented by the general formula (2) and the repeating unit represented by the general formula (3), Alternatively, a (meth) acrylic acid ester polymer such as a methyl methacrylate polymer composed of the repeating unit represented by the general formula (2) may be a linear polymer, or a block polymer, a core-shell polymer, or a branched polymer. It may be a ladder polymer or a crosslinked polymer. The block polymer may be an AB type, an ABC type, an ABA type, or any other type of block polymer. The core-shell polymer may be composed of only one core and only one shell, or each may be a multilayer.

  In the imide resin of the present invention, the type containing the general formula (3) is substantially aligned by adjusting the amount of each structural unit and the content of glutarimide units in the methyl methacrylate-styrene copolymer. It is also possible to provide features that do not have refraction. Oriented birefringence refers to birefringence that develops when stretched at a predetermined temperature and a predetermined stretch ratio. In the present specification, unless otherwise specified, it means birefringence that develops when stretched 100% at a temperature 5 ° C. higher than the glass transition temperature of the imide resin.

Here, the orientation birefringence is the product of the intrinsic birefringence derived from the polymer structure and the orientation distribution function derived from the molecular orientation state. The refractive index (nx) in the stretching axis direction and the axial refractive index (ny) orthogonal thereto. ) From the following expression Δn _or = nx−ny
The phase difference Re (nm) measured by a phase meter is divided by the thickness d (μm).
Oriented birefringence Δn _or = Re / d
As described above, the orientation birefringence is the difference between the refractive index (nx) in the stretching axis direction and the refractive index (ny) in the axial direction perpendicular thereto, and therefore, when nx is larger than ny, it shows a positive value and vice versa. When nx is smaller than ny, a negative value is indicated.

The value of orientation birefringence is preferably −0.1 × 10 ^{−3 to} 0.1 × 10 ⁻³ , and preferably −0.01 × 10 ^{−3 to} 0.01 × 10 ^−3. More preferred. When the orientation birefringence is out of the above range, the birefringence is likely to occur during the molding process with respect to the environmental change, and it becomes difficult to obtain stable optical characteristics.

  In order to obtain an imide resin having substantially no orientation birefringence, the amount of each structural unit in the (meth) acrylate-aromatic vinyl copolymer such as methyl methacrylate-styrene copolymer is adjusted, Furthermore, it is necessary to prepare the degree of imidization, and the repeating unit represented by the general formula (1) and the repeating unit represented by the general formula (3) are 2.0: 1.0 to 4.0 by weight ratio. Is preferably in the range of 1.0, more preferably in the range of 2.5: 1.0 to 4.0: 1.0, and in the range of 3.0: 1.0 to 3.5: 1.0. Is more preferable.

The imide resin preferably has a weight average molecular weight of 1 × 10 ⁴ to 5 × 10 ⁵ . When the weight average molecular weight is less than 1 × 10 ⁴ , the mechanical strength in the case of a molded product is insufficient, and when it exceeds 5 × 10 ⁵ , the viscosity at the time of melting is high and the molding processability is lowered. The productivity of the molded product may be reduced.

  The glass transition temperature of the imide resin of the present invention is preferably 110 ° C. or higher, and more preferably 120 ° C. or higher. When the glass transition temperature is lower than the above value, the application range is limited in applications where heat resistance is required.

  If necessary, other thermoplastic resins can be added to the imide resin of the present invention.

  When molding, generally used antioxidants, heat stabilizers, plasticizers, lubricants, UV absorbers, antistatic agents, colorants, shrinkage inhibitors, etc. are added within the range that does not impair the purpose of the present invention. May be.

  Molded articles obtained from the imide resin of the present invention include, for example, imaging fields such as cameras, VTRs, projector lenses, viewfinders, filters, prisms, and Fresnel lenses, and optical disk pickups such as CD players, DVD players, and MD players. Information equipment such as lenses such as lenses, optical recording fields for optical discs such as CD players, DVD players, and MD players, liquid crystal light guide plates, liquid crystal display films such as polarizer protective films and retardation films, and surface protective films Field, optical communication field such as optical fiber, optical switch, optical connector, etc., automotive headlight, tail lamp lens, inner lens, instrument cover, sunroof, etc., vehicle field, glasses, contact lens, internal vision lens, need for sterilization Doctor Medical equipment field such as supplies, road translucent plates, paired glass lenses, lighting windows and carports, lighting lenses and covers, building materials such as sizing for building materials, microwave cooking containers (tableware), home appliances It can be used for housings, toys, sunglasses, stationery, etc.

  The present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In addition, each measuring method of the physical property measured in the following Examples and Comparative Examples is as follows.

(1) Measurement of imidation rate The pellet of the product was used as it was, and IR spectrum was measured at room temperature using TravelIR manufactured by SensIR Technologies. From the obtained spectrum, the absorption intensity (Abs _Ester) attributed to the ester carbonyl group of 1720 cm ^-1, the imidization ratio from the ratio of the absorption intensity assignable to an imide carbonyl group of 1660cm ^-1 (Abs _imide) (Im %). Here, the imidation rate refers to the proportion of the imide carbonyl group in all carbonyl groups.

(2) Glass transition temperature (Tg)
Using 10 mg of the product, a differential scanning calorimeter (DSC, model DSC-50 manufactured by Shimadzu Corporation) was used to measure under a nitrogen atmosphere at a heating rate of 20 ° C./min, and determined by the midpoint method. .

(3) Measurement of ratio of carboxyl group remaining in resin 0.3 g of the product was dissolved in 37.5 ml of methylene chloride, and 37.5 ml of methanol was added. Two drops of 1 wt% phenolphthalein ethanol solution were added to this solution. 5 ml of 0.1N sodium hydroxide aqueous solution was added and stirred for 1 hour. 0.1N hydrochloric acid was added dropwise to this solution, and the amount of 0.1N hydrochloric acid added (Aml) until the reddish purple color of the solution disappeared was measured.

  Next, two drops of 1 wt% phenolphthalein ethanol solution were added to a mixed solution of 37.5 ml of methylene chloride and 37.5 ml of methanol. To this, 5 ml of 0.1N sodium hydroxide aqueous solution was added and stirred for 1 hour. 0.1N hydrochloric acid was added dropwise to this solution, and the amount of 0.1N hydrochloric acid added (Bml) until the reddish purple color of the solution disappeared was measured.

The ratio of the carboxyl group remaining in the resin was Cmmol / g, and the following formula was used.
C = 0.1 × (5-AB) /0.3)
(4) Measurement of the amount of residual dimethyl carbonate in the product 0.5 g of the product was dissolved in 10 ml of methylene chloride, and this was used as a sample. 3 μl of the sample was injected into a gas chromatograph (Gas Chromatograph GC-2010AF manufactured by Shimadzu Corporation, detector FID, capillary column (Rtx-1 manufactured by Restec Inc.)), and the concentration of dimethyl carbonate remaining in the product was calculated. .

(5) Total light transmittance A test piece having a size of 50 mm in length and 50 mm in width was cut out from the obtained sheet-like molded product having a thickness of 3 mm. This test piece was measured according to JIS K7105 at a temperature of 23 ° C. ± 2 ° C. and a humidity of 50% ± 5% using a turbidimeter 300A manufactured by Nippon Denshoku Industries Co., Ltd.

(6) Turbidity The test piece obtained in (5) was measured according to JIS K7136 at a temperature of 23 ° C. ± 2 ° C. and a humidity of 50% ± 5% using a Nippon Denshoku turbidity meter 300A. .

(7) Unevenness of film thickness A sample having a length of 300 mm in the TD direction and a length of 50 mm in the MD direction was cut out from the film, and the thickness of the full width in the TD direction was measured using an Anritsu contact type continuous thickness meter KB601B. From the measured thickness, the following formula was used to determine the thickness unevenness for the target film thickness of 150 μm using the following formula.
[Thickness unevenness] = | maximum thickness-minimum thickness | / 2
(8) Film appearance inspection Two samples having a length of 500 mm in the TD direction and a length of 500 mm in the MD direction are cut out from the film and irradiated with light from a desk stand (National SQ948H, fluorescent lamp 27W) in the dark room. The die line and the presence or absence of foaming were visually evaluated.

(9) ASTM No. 1 dumbbell specimen appearance inspection The surface of 10 dumbbell specimens was visually observed to evaluate the presence or absence of flow marks and foaming.

(Production Example 1)
Using commercially available polymethyl methacrylate (Sumitex MG manufactured by Sumitomo Chemical Co., Ltd.) as a raw material resin, monomethylamine as an imidizing agent, and IRGANOX 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) as an imidizing agent, A modified resin was produced.

  The extruder used was a meshing type co-rotating twin screw extruder having a diameter of 15 mm. The set temperature of each temperature control zone of the extruder was 230 ° C., and the screw rotation speed was 150 rpm. A resin prepared by dry blending 0.2 parts by weight of a heat stabilizer from a hopper is supplied at 1 kg / hr. After the resin is melted and filled by a kneading block, 5 parts by weight of monomethylamine is injected from the nozzle to the resin. did. A reverse flight was placed at the end of the reaction zone to fill the resin. By-products and excess methylamine after the reaction were removed by reducing the pressure at the vent port to -0.092 MPa. The resin that came out as a strand from a die provided at the exit of the extruder was cooled in a water tank and then pelletized with a pelletizer.

  Next, in a meshing type co-rotating twin screw extruder with a diameter of 15 mm, the set temperature of each temperature control zone of the extruder was 230 ° C. and the screw rotation speed was 150 rpm. The imide resin obtained from the hopper was supplied at 1 kg / hr, and the resin was melted and filled with a kneading block. Then, a mixed solution of 8 parts by weight of dimethyl carbonate and 2 parts by weight of triethylamine was added to the resin from the nozzle. Injection and reduction of carboxyl groups in the resin were performed. A reverse flight was placed at the end of the reaction zone to fill the resin. The by-product after reaction and excess dimethyl carbonate were removed by reducing the pressure at the vent port to -0.092 MPa. The resin that came out as a strand from a die provided at the exit of the extruder was cooled in a water tank and then pelletized with a pelletizer.

  Furthermore, the obtained imide resin was in a meshing type co-rotating twin-screw extruder having a diameter of 15 mm, the set temperature of each temperature control zone of the extruder was 230 ° C., the screw rotation speed was 150 rpm, and the supply amount was 1 kg / hr. The dimethyl carbonate was removed again by reducing the pressure at the vent port to -0.095 MPa. The resin that came out as a strand from a die provided at the exit of the extruder was cooled in a water tank and then pelletized with a pelletizer.

  Table 1 shows the imidization rate of the obtained imide resin, the glass transition temperature, the ratio of carboxyl groups remaining in the resin before and after the carboxyl group reduction step, and the amount of dimethyl carbonate before and after the step of removing dimethyl carbonate again under reduced pressure.

(Production Example 2)
The same procedure as in Production Example 1 was conducted except that the raw material resin was a commercially available methyl methacrylate-styrene copolymer (Sumipex HS manufactured by Sumitomo Chemical Co., Ltd.) and methylamine was 40 parts by weight based on the resin.

  Table 1 shows the imidization rate of the obtained imide resin, the glass transition temperature, the ratio of carboxyl groups remaining in the resin before and after the carboxyl group reduction step, and the amount of dimethyl carbonate before and after the step of removing dimethyl carbonate again under reduced pressure.

(Comparative Production Example 1)
The same procedure as in Production Example 1 was performed except that the step of removing dimethyl carbonate again under reduced pressure was omitted.

  Table 1 shows the imidization ratio, glass transition temperature, ratio of carboxyl groups remaining in the resin before and after the carboxyl group reduction step, and the amount of dimethyl carbonate.

(Comparative Production Example 2)
The same procedure as in Production Example 1 was carried out except that the carboxyl group reducing step and the step of removing dimethyl carbonate again under reduced pressure were omitted.

  Table 1 shows the imidization ratio, glass transition temperature, ratio of carboxyl groups remaining in the resin, and dimethyl carbonate content of the obtained imide resin.

(Comparative Production Example 3)
The same procedure as in Production Example 2 was performed except that the step of removing dimethyl carbonate under reduced pressure was omitted.

  Table 1 shows the imidization ratio, glass transition temperature, ratio of carboxyl groups remaining in the resin before and after the carboxyl group reduction step, and the amount of dimethyl carbonate.

(Comparative Production Example 4)
The same procedure as in Production Example 2 was performed except that the carboxyl group reduction step and the step of removing dimethyl carbonate again under reduced pressure were omitted.

  Table 1 shows the imidization ratio, glass transition temperature, ratio of carboxyl groups remaining in the resin, and dimethyl carbonate content of the obtained imide resin.

（実施例１）
製造例１で得られたイミド樹脂を、１００℃で５時間乾燥後、４０ｍｍφ単軸押出機と４００ｍｍ幅のＴダイを用いて、シリンダーおよびＴダイ温度２５５℃で吐出量２０ｋｇ／ｈｒで押出し、シート状の溶融樹脂を冷却ドラムで冷却して幅約６００ｍｍ、厚み１５０μｍ程度のフィルムを得た。得られたフィルムの全光線透過率、濁度、厚みむら、外観検査を表２に示す。

Example 1
The imide resin obtained in Production Example 1 was dried at 100 ° C. for 5 hours, and then extruded using a 40 mmφ single-screw extruder and a 400 mm wide T die at a cylinder and T die temperature of 255 ° C. at a discharge rate of 20 kg / hr. The sheet-like molten resin was cooled with a cooling drum to obtain a film having a width of about 600 mm and a thickness of about 150 μm. Table 2 shows the total light transmittance, turbidity, thickness unevenness, and appearance inspection of the obtained film.

（実施例２）
製造例２で得られたイミド樹脂を用いた以外は、実施例１と同様方法で厚み１５０μｍ程度のフィルムを得た。得られたフィルムの全光線透過率、濁度、厚みむら、外観検査を表２に示す。

(Example 2)
A film having a thickness of about 150 μm was obtained in the same manner as in Example 1 except that the imide resin obtained in Production Example 2 was used. Table 2 shows the total light transmittance, turbidity, thickness unevenness, and appearance inspection of the obtained film.

(Example 3)
The imide resin obtained in Production Example 1 was dried at 100 ° C. for 5 hours, and then an injection molding machine (clamping pressure: 80 tons) was used. The cylinder temperature was 255 ° C., the mold temperature was 50 ° C., and the thickness was 3. An ASTM No. 1 dumbbell test piece of 2 mm (length: 127 mm, width: 12.7 mm) was obtained. Table 2 shows an appearance inspection of the obtained dumbbell.

Example 4
An ASTM No. 1 dumbbell test piece having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained in the same manner as in Example 3 except that the imide resin obtained in Production Example 2 was used. Table 2 shows an appearance inspection of the obtained dumbbell.

(Comparative Example 1)
A film having a thickness of about 150 μm was obtained in the same manner as in Example 1 except that the imide resin obtained in Comparative Production Example 1 was used. Table 3 shows the total light transmittance, turbidity, thickness unevenness, and appearance inspection of the obtained film.

（比較例２）
比較製造例２で得られたイミド樹脂を用いた以外は、実施例１と同様方法で厚み１５０μｍ程度のフィルムを得た。得られたフィルムの全光線透過率、濁度、厚みむら、外観検査を表３に示す。

(Comparative Example 2)
A film having a thickness of about 150 μm was obtained in the same manner as in Example 1 except that the imide resin obtained in Comparative Production Example 2 was used. Table 3 shows the total light transmittance, turbidity, thickness unevenness, and appearance inspection of the obtained film.

(Comparative Example 3)
A film having a thickness of about 150 μm was obtained in the same manner as in Example 1 except that the imide resin obtained in Comparative Production Example 3 was used. Table 3 shows the total light transmittance, turbidity, thickness unevenness, and appearance inspection of the obtained film.

(Comparative Example 4)
A film having a thickness of about 150 μm was obtained in the same manner as in Example 1 except that the imide resin obtained in Comparative Production Example 4 was used. Table 3 shows the total light transmittance, turbidity, thickness unevenness, and appearance inspection of the obtained film.

(Comparative Example 5)
An ASTM No. 1 dumbbell test piece having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained in the same manner as in Example 3 except that the imidized resin obtained in Comparative Production Example 1 was used. Table 3 shows an appearance inspection of the obtained dumbbell.

(Comparative Example 6)
An ASTM No. 1 dumbbell test piece having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained in the same manner as in Example 3 except that the imidized resin obtained in Comparative Production Example 2 was used. Table 3 shows an appearance inspection of the obtained dumbbell.

(Comparative Example 5)
An ASTM No. 1 dumbbell test piece having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained in the same manner as in Example 3 except that the imidized resin obtained in Comparative Production Example 3 was used. Table 3 shows an appearance inspection of the obtained dumbbell.

(Comparative Example 6)
An ASTM No. 1 dumbbell test piece having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained in the same manner as in Example 3 except that the imidized resin obtained in Comparative Production Example 4 was used. Table 3 shows an appearance inspection of the obtained dumbbell.

Claims (5)

  An imide resin, wherein the ratio of carboxyl groups remaining in the resin is 0.3 mmol / g or less, and the concentration of the esterifying agent remaining in the resin is 1000 ppm or less. The imide resin according to claim 1, comprising a repeating unit represented by the following general formulas (1) and (2).

(Here, R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 18 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms. Or a substituent containing an aromatic ring having 5 to 15 carbon atoms.)

(Here, R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ represents an alkyl group having 1 to 18 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms. Or a substituent containing an aromatic ring having 5 to 15 carbon atoms.) The imide resin according to claim 1, further comprising a repeating unit represented by the general formula (3).

(Here, R ⁷ represents hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁸ represents an aryl group having 6 to 10 carbon atoms.)   The optical resin composition which has as a main component the imide resin of any one of Claims 1-3.   A molded article comprising the optical resin composition according to claim 4.