JP3378485B2 - Methyl methacrylate resin injection molding - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a methyl methacrylate resin injection molding. The present invention relates to an injection-molded product capable of forming a thin and large-sized molded product, which has been difficult with a conventional acrylic resin.

[0002]

2. Description of the Related Art Acrylic copolymers are rigid, have excellent transparency and weather resistance.
It is widely used as a molded product such as a liquid crystal display backlight light guide, a lighting cover, and a spectacle lens, and an extruded plate such as a signboard and a nameplate after extrusion molding. In order to melt and fluidize like injection molding or extrusion molding, it has high fluidity at the time of molding, and the finished molded product has excellent appearance, mechanical strength, heat resistance, solvent resistance, etc. Is desired. Recently, it has been desired to reduce the thickness of molded products without sacrificing the current performance for the purpose of economy and weight reduction. As an attempt to meet such a demand, a method of lowering the molecular weight of the polymer to improve the fluidity has been proposed. As a method of increasing the fluidity without lowering the molecular weight of the polymer, there is a method of adding a copolymerization component such as an acrylate ester. As an acrylic resin having a high solvent resistance of a polymer, an acrylic resin having a wider molecular weight distribution is disclosed in Japanese Patent Publication No. 58-455, Japanese Patent Publication No. 58-15490, and Japanese Patent Publication No. 62-34046. Has been done. As a methacrylic resin having high heat resistance, Japanese Patent Publication No. Sho 48-95491 discloses a powder of an unmelted cross-linked polymer having a gel fraction of 15% or more obtained by polymerization of methyl methacrylate and a polyfunctional monomer. An acrylic resin obtained by swelling methyl methacrylate and then polymerizing it is disclosed.

[0003]

However, the conventional resin composition having a high melt fluidity under high shear, which influences the injection molding characteristics, does not always have sufficient heat resistance, solvent resistance, mechanical properties and the like. In such a situation, the present inventors have diligently studied, and as a result, by using a specific resin composition, the melt fluidity under high shear that affects the injection molding characteristics is high, and the heat resistance, solvent resistance, and mechanical properties are high. The present inventors have found that a methyl methacrylate resin molded product having excellent properties which are seemingly contradictory to the melt fluidity such as, and capable of being thin and large in size can be obtained, and thus the present invention has been accomplished.

[0004]

That is, the present invention provides 23
A branched methyl methacrylate-based polymer having a melt flow rate at 0 ° C. of 10 to 70, a weight average molecular weight of 80,000 to 400,000, and a molecular weight between branch points defined by using the Z average molecular weight of 30,000 to 500,000. 30 to 100% by weight of the combined (A),
A methyl methacrylate-based resin injection-molded article comprising a methyl methacrylate resin composition containing 0 to 70% by weight of a rubbery polymer (B). Hereinafter, the present invention will be described in detail.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The branched methyl methacrylate polymer (A) of the present invention comprises a monofunctional monomer containing methyl methacrylate as a main component and a polyfunctional monomer copolymerizable therewith. It is united. The monofunctional monomer containing methyl methacrylate as a main component means methyl methacrylate alone or 5
It is a mixture of 0% by weight or more, preferably 70% by weight or more, of methyl methacrylate and a monofunctional unsaturated monomer copolymerizable with it. If the methyl methacrylate content is less than 50% by weight, the so-called polymethylmethacrylate characteristics, such as transparency and mechanical strength, are difficult to develop.

Examples of the copolymerizable monofunctional unsaturated monomer include, for example, methacrylic acid esters such as ethyl methacrylate, propyl methacrylate, butyl methacrylate and benzyl methacrylate: methyl acrylate, ethyl acrylate, acryl. Acrylic acid esters such as propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate:
Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and itaconic acid, acid anhydrides such as maleic anhydride and itaconic anhydride: 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, monoglycerol acrylate, Hydroxyl group-containing ester such as 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate and monoglycerol methacrylate: amides such as acrylamide, methacrylamide, diacetone acrylamide: nitriles such as acrylonitrile and methacrylonitrile: dimethyl methacrylate Nitrogen-containing monomers such as aminoethyl: Allyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, etc. Epoxy group-containing monomers: Styrene-based monomers such as styrene and α-methylstyrene That.

As the polyfunctional unsaturated monomer which can be copolymerized, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, etc. Ethylene glycol or its oligomers having both terminal hydroxyl groups esterified with acrylic acid or methacrylic acid; neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate, butanediol di (meth)
Acrylic acid or methacrylic acid esterified with a hydroxyl group of a dihydric alcohol such as acrylate; Polyhydric alcohol such as trimethylolpropane or pentaerythritol, or an ester of a polyhydric alcohol derivative thereof with acrylic acid or methacrylic acid; Examples thereof include aryl compounds having two or more alkenyl groups such as divinylbenzene.

The branched methyl methacrylate polymer (A) of the present invention has a melt flow rate of 10 to 70. It is preferably 20 to 50. Melt flow rate is 1
If it is less than 0, injection molding cannot be performed, or even if injection molding can be performed by increasing the injection pressure using a molding machine having a large mold clamping pressure, only a molded product having an inferior appearance can be obtained. On the other hand, when it exceeds 70, the mechanical strength is not sufficient and the strength of the injection-molded molded product is deteriorated.

The weight average molecular weight (Mw) of the branched methyl methacrylate polymer (A) of the present invention is 80,000 to 400,000. It is preferably 150,000 to 300,000. If the Mw is less than 80,000, the mechanical strength of the resin will be insufficient, and the strength of the molded product obtained by injection molding a methyl methacrylate resin composition containing this resin will be poor. If it is higher than 400,000, the melt viscosity will be high and injection will not be possible, or even if injection molding can be performed by increasing the injection pressure using a molding machine with a large mold clamping pressure, only a molded product having a poor appearance can be obtained.

The branched methyl methacrylate polymer (A) of the present invention has a molecular weight between branch points (Mzb) defined by its Z average molecular weight (Mz) of 30,000 to 500,000,
It is preferably 50,000 to 200,000. If the molecular weight between branch points (Mzb) exceeds 500,000, the tension of the resulting resin composition during melt drawing will be poor, and the extrusion performance of the composition will be poor. On the other hand, when the molecular weight between the branch points is less than 30,000, the mechanical strength is poor and the appearance of the molded product is poor.

Here, Mw and Mz are values obtained by gel permeation chromatography (GPC) and a differential refractometer. For example, 1
1994 edition "Polymer property analysis" (Kyoritsu Shuppan), page 24 ~
It is described on page 55.

The molecular weight between branch points means the average value of the molecular weight from a branch point to the next branch point in a polymer having a branched structure, and is defined by using the Z average molecular weight (Mz). The molecular weight between branch points (Mzb) defined by using this Z-average molecular weight is as follows, Journal of Japan Rubber Association, Vol. 45, No. 2,
It is calculated from the following [Equation 1] and [Equation 2] based on the description of "Characterization" on pages 105 to 118.

[0013]

[Equation 1] [[η ₁ ] / [η ₂ ]] ^10/6 = [(1 + Bz /
6) ^0.5 + 4Bz / 3π] ^-0.5

[0014]

## EQU00002 ## Mzb = Mz / Bz

In the above formula (1), [η ₁ ] is
The relationship between the intrinsic viscosity and the absolute molecular weight of the polymer to be measured obtained by using a universal calibration curve, which shows the relationship between the product of the intrinsic viscosity and the absolute molecular weight with respect to the GPC elution time of a linear methyl methacrylate polymer standard sample, is shown. In the calibration curve, the molecular weight is the intrinsic viscosity corresponding to the Mz value. [
[eta] ₂ ] is the intrinsic viscosity for the same molecular weight Mz value as the polymer to be measured in the calibration curve showing the relation of the intrinsic viscosity to the absolute molecular weight of the linear methyl methacrylate polymer standard sample. Bz is the number of branch points in the Z average molecular weight Mz.

In the branched methyl methacrylate polymer (A) of the present invention, when the ratio of the polymer having a molecular weight of 300,000 or more and the reduced viscosity of the polymer is 0.7 dl / g or less, {[14 × (reduced viscosity value) -6.8] to [1
4 × (reduced viscosity value) +11.2]} (wt%),
When the reduced viscosity is 0.7 dl / g or more, it is preferably {[40 × (reduced viscosity value) −25] to [40 × (reduced viscosity value) −7]} (wt%). The reduced viscosity expressed in the present invention means the polymer to be measured in chloroform at 25 ° C.
Is the value when the solution concentration is 1 g / dl.

Branched methyl methacrylate polymer (A)
When the ratio of the polymer having a molecular weight of 300,000 or more is within the above range,
The branched methyl methacrylate polymer (A) has an excellent balance between the fluidity and the tensile strength at the time of melting, and accordingly, the resin composition obtained using the same has a good balance between the fluidity and the strength at the time of melt drawing. A good molded product can be obtained by being excellent. The degree of crosslinking of the branched methyl methacrylate-based polymer (A) in the present invention is usually 3% or less, preferably 1% or less, expressed as a gel fraction (% by weight of acetone- insoluble portion relative to the total weight of the polymer). , And more preferably about 0%.

The branched methyl methacrylate polymer (A) of the present invention comprises the above-mentioned monomer of the structural unit, a predetermined amount of a component which becomes a polyfunctional structural unit, and if necessary, a chain transfer agent and / or Alternatively, it can be obtained by adding a polymerization initiator and polymerizing. As a component that becomes a polyfunctional constituent unit,
Mention may be made of polyfunctional monomers, polyfunctional chain transfer agents, polyfunctional initiators, and mixtures of two or more thereof. The amount of the component serving as the polyfunctional constituent unit is usually 0.02 to 1% by weight based on methyl methacrylate (and the monofunctional monomer).

The chain transfer agent may be a known one used in the polymerization of methyl methacrylate. Among these, there are monofunctional chain transfer agents having one chain transfer functional group and polyfunctional chain transfer agents having two or more chain transfer functional groups. Examples of monofunctional chain transfer agents include alkyl mercaptans and thioglycolic acid esters, and examples of polyfunctional chain transfer agents include ethylene glycol, neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, and tripenta. Examples include polyhydric alcohol hydroxyl groups such as erythritol and sorbitol esterified with thioglycolic acid or 3-mercaptopropionic acid.

Branched methyl methacrylate polymer (A)
The amount of the chain transfer agent used for the polymerization of
It is usually 5 × 10 ⁻⁵ mol to 5 × 10 ⁻³ mol per mol, and the amount of the polyfunctional copolymerizable monomer is usually 1 mol per mol of the monofunctional monomer. It is in the range of x10 ^-5 to {the chain transfer agent (mol) -2.5x10 ^-4 } equivalent.

Branched methyl methacrylate polymer (A)
The weight average molecular weight of is generally governed mainly by the concentration of the polyfunctional monomer used, the concentration of the chain transfer agent and the concentration of the radical initiator. The adjustment of the polymerization average molecular weight, considering that the higher the polyfunctional monomer concentration is, the larger the polymerization average molecular weight is, and conversely, the higher the concentration of the chain transfer agent is, the smaller the polymerization average molecular weight is.
It is carried out by appropriately changing the concentration within the above-mentioned concentration range of the polyfunctional monomer and within the concentration range of the chain transfer agent. The molecular weight between branch points can be adjusted mainly by the concentration of the polyfunctional monomer. The higher the polyfunctional monomer concentration, the smaller the molecular weight between branch points. Further, in the chain transfer agent, the higher the concentration of the polyfunctional chain transfer agent, the smaller the molecular weight between branch points. The ratio of the molecular weight of 300,000 or more increases as the concentration of the polyfunctional monomer increases.

As the polymerization initiator, there are a monofunctional polymerization initiator that generates a pair of radicals in one molecule and a polyfunctional polymerization initiator that generates two or more pairs of radicals. Examples of the monofunctional polymerization initiator, for example, 2,2 '- azobis (2,4-dimethylvaleronitrile), azobisisobutyronitrile, azo compounds such as dimethyl 2,2'-azobisisobutyrate; t-butyl peroxypivalate, t-butyl peroxy 2-ethylhexanoate,
Peroxyesters such as cumylperoxy 2-ethylhexanoate; organic peroxides such as diacyl peroxides such as di-3,5,5-trimethylhexanoyl peroxide and diacyl peroxide such as dilauroyl peroxide; Can be mentioned. Examples of polyfunctional polymerization initiators include bifunctional 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane and di-t.
- butylperoxy trimethyl adipate, trifunctional tris - (t-Buchirupakishi) triazine, tetrafunctional
2 include a 2-bis (4,4-di -t- butyl peroxy cyclohexyl) propane or the like.

When the polymerization is terminated at a polymerization rate of 45 to 60% by weight as in the bulk polymerization method, the use of a trifunctional or higher polyfunctional polymerization initiator will result in a higher polyfunctionality than branching by a polyfunctional monomer alone. The amount of unreacted vinyl groups due to the monomer can be reduced. When a polyfunctional polymerization initiator is used, it can be replaced with some or all of the above-mentioned polyfunctional constitutional units. The amount of the polymerization initiator used may be a well-known appropriate amount according to the polymerization method, and the monomer or the monomer mixture 10
About 0 to 1 part by weight, usually about 0.001 to 1 part by weight,
It is preferably 0.01 to 0.7 parts by weight. It should be noted that the larger the amount of the polymerization initiator, the smaller the weight average molecular weight, as in the case of a general methyl methacrylate polymer.

As the polymerization method for obtaining the branched methyl methacrylate-based polymer (A) of the present invention, a well-known polymerization method for producing a general methyl methacrylate-based polymer, that is, a suspension polymerization method, a bulk polymerization method, An emulsion polymerization method can be applied.

The rubber-like polymer (B) in the present invention includes (1) an acrylic multi-layer structure elastic body or (2)
A graft copolymer obtained by graft-polymerizing 95 to 20 parts by weight of an ethylenically unsaturated monomer on 80 parts by weight of a rubber-like polymer is preferably used.

(1) The acrylic multi-layer structure elastic body is an acrylic polymer in which 20 to 60 parts by weight of a rubber elastic layer or an elastomer layer having at least a two-layer structure is internally contained, and includes a soft layer and an outermost layer. It is based on a hard layer,
The structure may further include the innermost hard layer. For example,
JP-B-55-27576, JP-A-6-80739
The materials described in JP-A No. 49-23292 and JP-A No. 49-23292 can be used.

(2) As a rubber-like polymer in a graft copolymer obtained by graft-polymerizing 95 to 20 parts by weight of an ethylenically unsaturated monomer in 5 to 80 parts by weight of a rubber-like polymer, for example, polybutadiene rubber, acrylonitrile / Diene rubbers such as butadiene copolymer rubber and styrene / butadiene copolymer rubber, acrylic rubbers such as polybutyl acrylate, polypropyl acrylate and poly-2-ethylhexyl acrylate, and ethylene / propylene /
A non-conjugated diene rubber or the like can be used. Examples of the ethylenic monomer and a mixture thereof used for graft-copolymerizing the rubber-like polymer include styrene, acrylonitrile, and alkyl (meth) acrylate. As these graft copolymers, Japanese Patent Laid-Open No. Sho 5
Those described in JP-A-5-147514 and JP-B-47-9740 can be used.

The proportion of the methyl methacrylate resin composition containing the rubbery polymer B is 30 to 100% by weight of the methyl methacrylate polymer (A) having a branched structure, and the rubbery polymer (B). Is 0 to 70% by weight. The impact resistance of the molded product decreases as the proportion of the rubber-like polymer (B) decreases, and when it exceeds 70% by weight, the heat resistance decreases and the branched methyl methacrylate polymer (A ) Is no longer effective.

A linear polymer (C) of ethylenic monomers may be further added to the resin composition of the present invention.
Such polymers include acrylic resins, styrene resins, vinyl chloride resins, acrylonitrile resins,
Examples thereof include vinylidene fluoride resin. The amount of the linear polymer (C) is 30% by weight or more of the branched methyl methacrylate polymer (A) and 5% by weight or more of the rubbery polymer (B) in the resin composition. Is.

The resin composition of the present invention can be made by any of the well known methods for making thermoplastic resin compositions. That is,
By melt-kneading a mixture of the branched methyl methacrylate polymer (A) or the rubber-like polymer (B) and / or the linear polymer (C) with a single-screw or twin-screw extruder. can get.

The methyl methacrylate-based resin composition of the present invention may contain a general release agent, ultraviolet absorber, colorant, antioxidant, heat stabilizer, plasticizer, antistatic agent, etc., if necessary. Various agents that can be added to the acrylic resin can be added.

The injection-molded article of the present invention can be thin and large. The ratio (L / T) of the longest flow distance (L) from the gate to the wall thickness (T) of the injection molded body is 10
A molded product of 0 to 600 can be easily obtained. In particular,
L / T of 200 to 6 which was difficult to manufacture in the past
It is also possible to produce a molded body of No. 00. The longest flow distance (L) from the gate represents the longest flow distance of the resin from the injection gate of the molten resin, that is, the distance to the end of the molded body. Large L / T means that if the wall thickness is the same. It indicates that a large-sized molded body can obtain a thinner molded body if the size is the same. The injection molding machine and its conditions are not special, and conventional ones can be used.

[0033]

INDUSTRIAL APPLICABILITY The methyl methacrylate resin composition used in the present invention has a high melt fluidity under high shear which influences the injection molding characteristics, and has a large size with excellent heat resistance, solvent resistance and mechanical properties. It is possible to provide a thin methyl methacrylate resin injection-molded product.

[0034]

EXAMPLES The present invention will be described below with reference to examples. Among the measuring methods, the items other than those described above were measured as follows. (1) MFR: Measured according to JIS K7210. The temperature is 23
The temperature was 0 ° C. and the load was 3.8 kgf. (2) Moldability: Using an injection molding machine IS-550F manufactured by Toshiba Machine Co., Ltd. and the following mold, molding was performed under the following conditions and evaluated. Mold; diameter 600mm, depth 100mm, thickness 2mm
The ratio (L / T) of the longest flow distance (L) from the gate to the wall thickness (T) of the mold hot runner and the central one-point gate injection-molded product is L = 600/2 = 30
Since 0 and T = 2, it becomes 150. Resin Drying; 75 ° C. × 4h r-type temperature; 50 ° C. set cylinder temperature; hot runner: 250 ° C., nozzle: 230 ℃, C1: 2
50 ° C, C2: 250 ° C, C3: 230 ° C, C4: 210 ° C Injection pressure setting; 70% injection rate; Speed back pressure of about 220cc / s; Gauge pressure 15kg / cm ² Screw rotation speed; 60rpm cycle; 50sec ( 3) Tensile strength The injection molding machine IS-130 of Toshiba Machine Co., Ltd. (JIS)
Use a mold conforming to K7113 and a cylinder temperature of 23.
A test piece was molded at 0 ° C and evaluated. A test piece for solvent resistance evaluation was also molded and provided for evaluation. (4) Solvent resistance Using a flat plate of 150 × 25 × 3 mmt, applying the cantilever method, fixing one end of the sample, using a point 6 cm away from it as a fulcrum, and applying a load to the other end of the sample Then, isopropyl alcohol was applied to the surface of the sample on the fulcrum, and the load at which the time after which the craze occurs after application was 100 seconds was expressed by stress.

Abbreviations of various monomers and chain transfer agents used in the examples are as follows. -MMA: methyl methacrylate-MA: methyl acrylate-DDSH: n-dodecyl mercaptan-HDA: 1,6-hexanediol diacrylate The weight average molecular weight Mw and Z average molecular weight Mz are the same as those shown above. , A value determined by gel permeation chromatography (GPC) and a differential refractometer.

Reference Examples A1 and A2 "Production of Branched Methyl Methacrylate Polymer (A)" 2
The amount of methyl methacrylate, methyl acrylate, 1,6-hexanediol diacrylate and n-dodecyl mercaptan shown in [Table 1], 0.3 part by weight of lauroyl peroxide, and 200 parts of deionized water were placed in a 00 liter SUS autoclave. Parts by weight, 1 part by weight of sodium polymethacrylate are added and mixed, heated and heated to 80 ° C.
Polymerization was started in (1), and after 90 minutes, it was further polymerized at 100 ° C. for 60 minutes. After the polymerization, washing, dehydration and drying were carried out to obtain a beaded polymer, and the beads were pelletized by a uniaxial extruder having a screw diameter of 40 mm manufactured by Tanabe Plastics Co., Ltd. The evaluation results of the obtained polymer are shown in [Table 1].

Reference Example C "Production of Linear Methyl Methacrylate Polymer (C)" 2
Methyl methacrylate, methyl acrylate, and n-dodecyl mercaptan were added to a 00-liter SUS autoclave in the amounts shown in [Table 1] and lauroyl peroxide 0.3.
Parts by weight, 200 parts by weight of deionized water, and 1 part by weight of sodium polymethacrylate are added and mixed, heated and heated to 8
Polymerization was started at 0 ° C, and after 90 minutes, it was further heated at 100 ° C for 6
It was polymerized for 0 minutes. After the polymerization, washing, dehydration and drying were carried out to obtain a beaded polymer, and the beads were pelletized by a uniaxial extruder having a screw diameter of 40 mm manufactured by Tanabe Plastics Co., Ltd. The evaluation results of the obtained polymer are shown in [Table 1].

[0038]

[Table 1] Note 1: HDA per mole of MMA and MA
Number of functional groups (mol)

Example 1 A1 of [Table 1] produced in Reference Example as a branched methyl methacrylate polymer (A) was dried at 80 ° C. for 4 hours,
Toshiba Machine (manufactured) injection molding machine IS-550F, diameter 6
The moldability was evaluated by using a circular container mold of 00 mm, depth 100 mm, and thickness 2 mm, and molding under the conditions shown above. In addition, a test piece was molded with an injection molding machine IS-130 manufactured by Toshiba Machine Co., Ltd., and the tensile strength and the solvent resistance were evaluated. The results are shown in [Table 2].

Example 2 A2 of [Table 1] produced in Reference Example as a branched methyl methacrylate polymer (A) was molded in the same manner as in Example 1,
evaluated. The results are shown in [Table 2].

Example 3 80% by weight of A1 was used as the branched methyl methacrylate polymer (A), and Orogras DR was used as the rubber polymer (B).
20 parts by weight of 101 (manufactured by Rohm & Haas) was blended and granulated using an extruder. The obtained blend was molded and evaluated in the same manner as in Example 1. The results are shown in [Table 2].

Comparative Example 1 Instead of the branched methyl methacrylate polymer (A),
It was molded and evaluated in the same manner as in Example 1 except that the linear methyl methacrylate polymer C shown in [Table 1] was used.
The evaluation results are shown in [Table 2], but the moldability was poor and a good molded product could not be obtained.

Example 4 Sumipex HT013E as the rubber-like polymer (B)
Molding and evaluation were performed in the same manner as in Example 3 except that (Sumitomo Chemical Co., Ltd.) was used. The results are shown in [Table 2].

Comparative Example 2 Instead of the branched methyl methacrylate polymer (A),
It was molded and evaluated in the same manner as in Example 3 except that the linear methyl methacrylate polymer C shown in [Table 1] was used.
The evaluation results are shown in [Table 2], but the moldability was poor and a good molded product could not be obtained.

[0045]

[Table 2] ○ means good, △ means good, and × means bad.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-9-59472 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 33 / 12,51 / 04,21 / 00 B29C 45/00

Claims (5)

(57) [Claims] 1. A melt flow rate at 230 ° C. of 1
A branched methyl methacrylate-based polymer (A) having a weight average molecular weight of 0 to 70 and a weight average molecular weight of 80,000 to 400,000, and a molecular weight between branch points defined by using the Z average molecular weight of 30,000 to 500,000 is used.
~ 100 wt%, 0-70 wt% rubbery polymer (B)
A methyl methacrylate-based resin injection-molded article containing the methyl methacrylate resin composition. 2. The ratio (L / T) of the longest flow distance (L) from the gate to the wall thickness (T) of the injection molded body is 100 to 60.
The methylmethacrylate-based resin injection-molded product according to claim 1, which is 0. 3. The ratio (L / T) of the longest flow distance (L) from the gate to the wall thickness (T) of the injection-molded article is 200 to 60.
The methylmethacrylate-based resin injection-molded product according to claim 1, which is 0. 4. A methyl methacrylate resin injection-molded article according to claim 1, wherein the rubber-like polymer (B) is a multi-layered elastic body. 5. The rubber-like polymer (B) is a graft copolymer obtained by graft-polymerizing 95 to 20 parts by weight of an ethylenically unsaturated monomer onto 5 to 80 parts by weight of a rubber-like polymer. Injection molding of methyl methacrylate resin.