JP5762682B2 - Styrene-methacrylic acid-methyl methacrylate resin composition, extruded sheet and molded article - Google Patents

Description

The present invention is formed using a styrene-methacrylic acid-methyl methacrylate resin composition excellent in heat resistance, appearance, mechanical strength, and moldability, and the styrene-methacrylic acid-methyl methacrylate resin composition. And non-foamed and foamed extruded sheets and molded articles.

  Styrene-methacrylic acid resin is excellent in heat resistance and relatively inexpensive, so it can be used for food containers such as lunch boxes and prepared dishes, packaging materials, foam boards for thermal insulation of houses, and diffusion of liquid crystal televisions containing a diffusion agent Widely used for plates and the like. In recent years, in order to popularize microwave ovens used for business, such as convenience stores, and to shorten the usage time of microwave ovens, higher output devices (which are likely to become hot in a short time) have been used. For this reason, a resin having higher heat resistance and excellent moldability is desired.

  However, in the styrene-methacrylic acid resin, it is necessary to increase the content of methacrylic acid in order to obtain a resin having higher heat resistance. In this case, a gelled product due to methacrylic acid is easily generated, and an appearance defect may be observed on the sheet surface. In particular, this phenomenon is seen when the non-foamed sheet is extruded and devolatilized in vacuum from the extruder vent for the purpose of removing moisture and low-molecular residual volatiles. An increase in methacrylic acid also leads to a decrease in mechanical strength. As for a styrene-methacrylic acid resin, Patent Document 1 discloses a method of adding water or alcohol as a method of suppressing the formation of gelled product. Patent Document 2 discloses a method of adding 2-ethyl-hexyl alcohol to a polymerization raw material liquid in Examples, and Patent Document 3 discloses a method of adding octyl alcohol to a polymerization raw material liquid in Examples. ing. Further, a styrene-methacrylic acid-methyl methacrylate copolymer is disclosed in Patent Document 4.

JP 56-161409 A JP 09-87332 A JP 2006-282963 A Japanese Patent Laid-Open No. 1-279911

  However, the above-described method does not have sufficient gelation suppression effect, is more difficult to gel, has excellent heat resistance, appearance and mechanical strength, and requires a non-foamed or foamed molded product made of a resin having excellent moldability. It has been.

The present invention is formed using a styrene-methacrylic acid-methyl methacrylate resin composition excellent in heat resistance, appearance, mechanical strength, and moldability, and the styrene-methacrylic acid-methyl methacrylate resin composition. Non-foamed and foamed extruded sheets and molded articles are provided.

In light of the above problems, the present inventors have conducted extensive research and, as a result, used a conventional resin having a specific composition in which methyl methacrylate is added to styrene-methacrylic acid, and residual styrene in the resin, dimer and It was found that by adjusting the concentration of the trimer to a specific range, a styrene-methacrylic acid-methyl methacrylate resin composition having an appearance and mechanical strength which could not be expected so far can be obtained. -It has been found that excellent non-foamed and foamed molded articles can be obtained from the methacrylic acid-methyl methacrylate resin composition , and the present invention has been completed. That is, the present invention is as follows.

[1] When the total content of the styrene monomer unit, the methacrylic acid monomer unit, and the methyl methacrylate monomer unit is 100 mass%, the content of the styrene monomer unit is 69 to 92 mass. %, The content of the methacrylic acid monomer unit is 6 to 16% by mass, the content of the methyl methacrylate monomer unit is 2 to 15% by mass, and the residual amount of styrene dimer and trimer Is a styrene-methacrylic acid-methyl methacrylate resin composition in which the total amount is 0.6 mass% or less and the residual amount of styrene monomer is 700 ppm or less.
[2] The weight average molecular weight (Mw) is 100,000 to 350,000, and the ratio (Mz / Mw) of the Z average molecular weight (Mz) to the weight average molecular weight (Mw) is 1.6 to 3.5. The styrene-methacrylic acid-methyl methacrylate resin composition according to the above [1].
[3] The styrene-methacrylic acid-methyl methacrylate resin composition according to the above [1] or [2], containing 0.02 to 1.0% by mass of an aliphatic primary alcohol having 14 or more carbon atoms . .
[4] The styrene-methacrylic acid-methyl methacrylate resin composition according to [3], wherein the aliphatic primary alcohol having 14 or more carbon atoms is an isoaliphatic primary alcohol having a freezing point of −10 ° C. or lower. Thing .
[5] A non-foamed extruded sheet formed using the styrene-methacrylic acid-methyl methacrylate resin composition according to any one of [1] to [4].
[6] A foamed extruded sheet formed using the styrene-methacrylic acid-methyl methacrylate resin composition according to any one of [1] to [4].
[7] A molded product formed by using the non-foamed extruded sheet according to [5] or the foamed extruded sheet according to claim 6.

According to the present invention, a styrene-methacrylic acid-methyl methacrylate resin composition excellent in heat resistance, appearance, mechanical strength, and moldability, and the styrene-methacrylic acid-methyl methacrylate resin composition are used. Non-foamed and non-foamed extruded sheets and molded articles can be provided.

FIG. 1 is a diagram illustrating a method for measuring the waist strength of a tray container in an example.

  Hereinafter, the present invention will be described in detail.

[Styrene-methacrylic acid-methyl methacrylate resin composition ]
In one embodiment of the present invention, when the total content of the styrene monomer unit, the methacrylic acid monomer unit, and the methyl methacrylate monomer unit is 100% by mass, the content of the styrene monomer unit is 69-92 mass%, content of methacrylic acid monomer unit is 6-16 mass%, content of methyl methacrylate monomer unit is 2-15 mass%, dimer and trimer of styrene A styrene-methacrylic acid-methyl methacrylate resin composition (hereinafter simply referred to as a resin composition) in which the total residual amount of the body is 0.6% by mass or less and the residual amount of the styrene monomer is 700 ppm or less. Is also provided.

In the present invention, when the total content of the styrene monomer unit, the methacrylic acid monomer unit, and the methyl methacrylate monomer unit is 100% by mass, the content of the styrene monomer unit is 69 to 92. It is mass%, Preferably it is 74-90 mass%, More preferably, it is 77-86 mass%. When the content is less than 69% by mass , the fluidity of the resin composition is lowered. When the content exceeds 92% by mass, a desired amount of a methacrylic acid monomer unit and a methyl methacrylate monomer unit described later may be present. Can not.

In the present invention, methacrylic acid plays a role of improving heat resistance. When the total content of the styrene monomer unit, the methacrylic acid monomer unit, and the methyl methacrylate monomer unit is 100% by mass, the content of the methacrylic acid monomer unit is 6 to 16% by mass. Yes, preferably 7 to 14% by mass, more preferably 9 to 13% by mass. If this content is less than 6% by mass, the effect of improving heat resistance is insufficient. On the other hand, when the amount exceeds 16% by mass, the gelled product in the resin composition increases, and further , the fluidity and mechanical properties of the resin composition are lowered, which is not preferable.

  Generally, styrene-methacrylic acid-based resins including styrene-methacrylic acid-methyl methacrylate resins are produced on an industrial scale by almost radical polymerization, but as described in Patent Documents 1 to 3 described above. In order to suppress the gelation reaction in the devolatilization step, various alcohols may be added to the polymerization system for polymerization.

In the present invention, methyl methacrylate is used for the purpose of suppressing the dehydration reaction of methacrylic acid by intermolecular interaction with methacrylic acid and improving the mechanical strength of the resin composition . Furthermore, it contributes to the improvement of resin composition characteristics such as weather resistance and surface hardness.

When the total content of the styrene monomer unit, the methacrylic acid monomer unit, and the methyl methacrylate monomer unit is 100% by mass, the content of the methyl methacrylate monomer unit is 2 to 15% by mass. Preferably, it is 3-12 mass%, More preferably, it is the range of 5-10 mass%. If this content is less than 2% by mass, it is insufficient for improving the gelation and improving the mechanical strength. Moreover, when it exceeds 15 mass%, the fluidity | liquidity of a resin composition falls and there exists a tendency for water absorption to increase, and it is unpreferable.

In addition, when methacrylic acid and methyl methacrylate are bonded side by side, if a high-temperature, high-vacuum devolatilizer is used, a demethanol reaction occurs depending on the conditions, and six-membered as described in Patent Document 4 above. A cyclic acid anhydride may be formed. The resin composition of the present invention may contain this six-membered cyclic acid anhydride, but it is preferable that the amount is less because it reduces fluidity. In the styrene-methacrylic acid-methyl methacrylate resin composition of the present invention, It is particularly preferable that the content of the six-membered cyclic acid anhydride is less than 0.1% by mass.

The contents of the styrene monomer unit, the methacrylic acid monomer unit, and the methyl methacrylate monomer unit can be obtained from integral ratios of spectra measured with a proton nuclear magnetic resonance ( ¹ H-NMR) measuring instrument, respectively. it can.

As a polymerization method of the styrene-methacrylic acid-methyl methacrylate resin composition of the present invention, a radical polymerization method, more specifically, a radical polymerization method by a bulk polymerization method or a solution polymerization method can be preferably employed. The polymerization method mainly comprises a polymerization step for polymerizing a polymerization raw material (monomer component) and a devolatilization step for removing volatile components such as unreacted monomers and polymerization solvent from the polymerization product. Here, the polymerization method of the present invention will be described.

When the polymerization raw material is polymerized in order to obtain the styrene-methacrylic acid-methyl methacrylate resin composition of the present invention, the polymerization raw material composition typically contains a polymerization initiator and a chain transfer agent. As the polymerization initiator, organic peroxides such as 2,2-bis (t-butylperoxy) butane, 2,2-bis (t-butylperoxy) octane, 1,1-bis (t-butylperoxy)- Peroxyketals such as 3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, di-t-butyl peroxide, t -Dialkyl peroxides such as butylcumyl peroxide, dicumyl peroxide, α, α'-bis (t-butylperoxyisopropyl) benzene, diacyl peroxides such as acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, diisopropyl peroxide Dicarbonate, G-2-ethylhexyl Peroxydicarbonates such as ruperoxydicarbonate and di-n-propylperoxydicarbonate, peroxyesters such as t-butylperoxyacetate and t-butylperoxyisobutyrate, ketone peroxides such as acetylacetone peroxide, methylethylketone peroxide, and hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, diisopropyl perbenzene hydroperoxide, and the like. Of these, 1,1-bis (t-butylperoxy) cyclohexane is preferable from the viewpoint of the decomposition rate and the polymerization rate.

  Examples of the chain transfer agent include α-methylstyrene linear dimer, n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, 1-phenyl-2-fluorene, dibenten and the like.

As the polymerization method, solution polymerization using a polymerization solvent can be employed as necessary. Examples of the polymerization solvent used include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, dialkyl ketones and, for example, methyl ethyl ketone, which may be used alone or in combination of two or more. Also good. Furthermore, other polymerization solvents such as aliphatic hydrocarbons can be mixed with aromatic hydrocarbons within a range that does not lower the solubility of the polymerization product. These polymerization solvents are in a range in which the content in a total of 100% by mass of the monomer (that is, styrene monomer, methacrylic acid monomer and methyl methacrylate monomer) does not exceed 25% by mass. Is preferably used from the viewpoints of good polymerization rate, good impact strength of the resulting resin composition , and good economic efficiency obtained by reducing the energy required for recovery of the polymerization solvent. . The polymerization solvent may be added after the polymerization has progressed and the reaction system becomes relatively high in viscosity, or may be added before the polymerization, but before the polymerization, The addition at a ratio of 20% by mass facilitates uniform quality and is preferable from the viewpoint of controlling the polymerization temperature.

  In the present invention, when the total content of the styrene monomer unit, the methacrylic acid monomer unit, and the methyl methacrylate monomer unit is 100% by mass, the residual amount of styrene dimer and trimer Is 0.6% by mass or less, preferably 0.5% by mass or less, and more preferably 0.4% by mass or less. If the total of the remaining amount of styrene dimer and trimer is 0.6% by mass or less, for example, in injection molding, adhesion of styrene dimer and trimer to the mold is greatly reduced. The transfer of the dimer and trimer to the molded product is greatly reduced, and the appearance defect is greatly improved. In extrusion molding of a sheet or the like, the amount of styrene dimer and trimer precipitated on the die is greatly reduced, transfer to the sheet is greatly reduced, and the appearance defect is greatly improved. Further, productivity can be improved because the necessity of cleaning the mold and the die outlet can be reduced. The residual amount of styrene dimer and trimer can be measured by gas chromatography.

In the present invention, when the total content of the styrene monomer unit, the methacrylic acid monomer unit, and the methyl methacrylate monomer unit is 100% by mass, the residual amount of the styrene monomer is 700 ppm or less. , Preferably 500 ppm or less, more preferably 400 ppm or less. If the residual amount of styrene monomer is 700 ppm or less, the odor around the die outlet during sheet extrusion is improved. Moreover , the color tone of the resin composition is also improved. The residual amount of styrene monomer can be measured by gas chromatography.

In the present invention, the weight average molecular weight of the styrene-methacrylic acid-methyl methacrylate resin composition is preferably 100,000 to 350,000, and the ratio of the Z average molecular weight (Mz) to the weight average molecular weight (Mw) (Mz / Mw). ) Is preferably 1.6 to 3.5. The weight average molecular weight is more preferably 130,000 to 300,000, still more preferably 160,000 to 250,000. When the weight average molecular weight is 100,000 to 350,000, a resin composition having an excellent balance between impact strength and fluidity can be obtained, and the gel material is also less mixed. The ratio of Mz / Mw is more preferably 1.7 to 3.0, and even more preferably 1.7 to 2.5. When the ratio of Mz / Mw is 1.6 to 3.5, a resin composition having an excellent balance between impact strength and fluidity is obtained, and there is a tendency that the gel material is less mixed. Mz and Mw can be measured in terms of polystyrene standard by gel permeation chromatography.

The styrene-methacrylic acid-methyl methacrylate resin composition of the present invention preferably contains an aliphatic primary alcohol having 14 or more carbon atoms. The addition of alcohol is effective for suppressing the gelation reaction due to the dehydration reaction of methacrylic acid as described in Patent Documents 1 to 3 described above. However, when the pressure is reduced with a vent or the like for removing low volatile components such as moisture and residual monomers during sheet extrusion, alcohol having less than 14 carbon atoms is likely to volatilize and suppress the gelation reaction. Fades. The content of the aliphatic primary alcohol having 14 or more carbon atoms in the styrene-methacrylic acid-methyl methacrylate resin composition is preferably 0.02 to 1.0% by mass. The content is more preferably 0.04 to 0.8% by mass, and still more preferably 0.06 to 0.6% by mass. Under the alcohol addition conditions such that the content is less than 0.02% by mass, the amount of the alcohol present in the devolatilization step is small, and the effect of suppressing the gelation reaction tends to be weakened. On the other hand, the adding conditions such as the content exceeds 1.0 wt%, although higher effect of suppressing gelation reaction, increases the amount of residual aliphatic primary alcohols in the resin composition, the resin composition There exists a tendency for the fall of the heat resistance of a thing to become large. In addition, generation of mold deposits is easily observed during molding. Among aliphatic primary alcohols having 14 or more carbon atoms, iso-type aliphatic primary alcohols having a freezing point of −10 ° C. or lower are particularly preferable. When the freezing point exceeds −10 ° C., when the pressure is reduced by a vent or the like for the purpose of removing low volatile components such as moisture and residual monomers, the alcohol is likely to be deposited in the condenser and the degree of vacuum may be lowered. The content of the aliphatic primary alcohol having 14 or more carbon atoms can be measured by gas chromatography.

  Examples of the aliphatic primary alcohol having 14 or more carbon atoms include n-myristic acid alcohol, n-palmitic acid alcohol, and n-stearyl alcohol. Furthermore, as the isoaliphatic primary alcohol having a freezing point of −10 ° C. or less, isotetradecanol having 14 carbon atoms, isohexadecanol having 16 carbon atoms, isooctadecanol having 18 carbon atoms, and 20 carbon atoms are included. Isoeicosanol is mentioned, for example, the following alcohol can be specifically mentioned as an example. 7-methyl-2- (3-methylbutyl) -1-octanol, 5-methyl-2- (1-methylbutyl) -1-octanol, 5-methyl-2- (3-methylbutyl) -1-octanol, 2- Hexyl-1-decanol, 5,7,7-trimethyl-2- (1,3,3-trimethylbutyl) -1-octanol, 8-methyl-2- (4-methylhexyl) -1-decanol, 2- Heptyl-1-undecanol, 2-heptyl-4methyl-1-decanol, 2- (1,5-dimethylhexyl)-(5,9-dimethyl) -1-decanol. Among these, isooctadecanol having 18 carbon atoms is particularly preferable.

  The styrene-methacrylic acid-methyl methacrylate resin of the present invention may contain a stabilizer. General stabilizers such as octadecyl-3- (3,5-tertiarybutyl-4-hydroxyphenyl) propionate, hindered phenolic antioxidants such as 4,6-bis (octylthiomethyl) -o-cresol And phosphorus processing heat stabilizers such as tris (2,4-di-tertiarybutylphenyl) phosphite. These stabilizers can each be used alone or in combination of two or more. About the addition time, it can add in a polymerization process or a devolatilization process, for example. Further, a stabilizer can be mixed into the resin by a mechanical device such as an extruder or a Banbury mixer.

What is necessary is just to select suitably the apparatus used at the superposition | polymerization process for obtaining the styrene-methacrylic acid-methyl methacrylate resin composition of this invention according to the polymerization method of a styrene resin. For example, in the case of bulk polymerization, a polymerization apparatus in which one or a plurality of complete mixing reactors are connected can be used. Further, regarding the devolatilization step, in the case of bulk polymerization, the polymerization proceeds until the unreacted monomer finally becomes preferably 50% by mass or less, more preferably 40% by mass or less, and the volatile content of the unreacted monomer and the like. In order to remove, it can be devolatilized by a known method. For example, a normal devolatilization apparatus such as a flash drum, a biaxial devolatilizer, a thin film evaporator, and an extruder can be used. In addition, the temperature of the devolatilization treatment is usually about 190 to 280 ° C, and from the viewpoint of suppressing the formation of a six-membered cyclic acid anhydride due to the adjacent methacrylic acid and methyl methacrylate, 190 to 260 ° C is more preferable. . Moreover, the pressure of a devolatilization process is about 0.13-4 kPa normally, Preferably it is 0.13-3 kPa, More preferably, it is 0.13-2.0 kPa. As the devolatilization method, for example, a method of removing volatile matter by reducing the pressure under heating and a method of removing the volatile matter through an extruder designed for the purpose of removing the volatile matter are desirable.

In the styrene-methacrylic acid-methyl methacrylate resin composition of the present invention, as desired, commonly used additives such as lubricants, antioxidants, ultraviolet absorbers, mold release agents, plasticizers, dyes, pigments, it is possible to add various fillers such as the Ru material name is added to such additives resin composition can be used in various molded. The additive may be added in advance when the styrene-methacrylic acid-methyl methacrylate resin composition is produced. The material also includes other resins than the styrene-methacrylic acid-methyl methacrylate resin of the present invention, such as general polystyrene, styrene-butadiene copolymer elastomer, partially or fully hydrogenated styrene-butadiene. A copolymer elastomer, polyphenylene ether, or the like can also be contained.

[Extruded sheet]
Another aspect of the present invention provides an extruded sheet formed using the above-described styrene-methacrylic acid-methyl methacrylate resin composition of the present invention. The extruded sheet may be non-foamed or foamed. As a method for producing an extruded sheet, a generally known method can be used. As a method for producing a non-foamed extrusion sheet, a short-axis or biaxial extrusion molding machine equipped with a T-die, a method using a device that pulls a sheet with a uniaxial stretching machine or a biaxial stretching machine, and the like can be used. As a method for producing the sheet, a method using an extrusion foam molding machine equipped with a T die or a circular die can be used.

  In the case of forming a foamed extruded sheet, materials usually used as a foaming agent and a foaming nucleating agent at the time of extrusion foaming can be used. As the foaming agent, butane, pentane, chlorofluorocarbon, carbon dioxide, water or the like can be used, butane is preferred. Moreover, talc etc. can be used as a foam nucleating agent.

Foam extrusion sheet, it is preferably a thickness 0.5 mm to 5.0 mm, preferably a apparent density 50 g / to 300 g / L, also a basis weight of 80g / m ² ~300g / m ² preferable. The foamed extruded sheet of the present invention may be multilayered by, for example, further laminating a film. The type of film used may be that used for general polystyrene.

  On the other hand, in the non-foamed extruded sheet, for example, the thickness is preferably about 0.1 to 1.0 mm from the viewpoint of rigidity and thermoforming cycle. The sheet may be formed only by ordinary low-magnification roll stretching. In particular, a sheet stretched about 1.3 to 7 times with a roll and then stretched about 1.3 to 7 times with a tenter is a strong surface. Is preferable. Further, it may be used as a multilayer with a styrene resin such as polystyrene resin. Further, it may be used in a multilayer with a resin other than the styrenic resin. Examples of resins other than styrene resins include PET resins and nylon resins.

  Another aspect of the present invention provides a molded article formed by using the above-described non-foamed extruded sheet or foamed extruded sheet of the present invention. The foamed extruded sheet or the multilayer body including the foamed sheet can be molded by, for example, vacuum forming to produce a container such as a tray. In addition, the non-foamed extruded sheet can be formed, for example, by vacuum forming to prepare a container for a lunch box lid, side dish, or the like.

EXAMPLES Next, although an Example and a comparative example demonstrate this invention in detail, this invention is not necessarily limited to these Examples. The analysis and evaluation methods for resin compositions and extruded sheets in Examples and Comparative Examples are as follows.

[Properties of resin composition ]
(1) Content of each monomer unit of styrene, methacrylic acid and methyl methacrylate The resin composition was quantified from the integral ratio of the spectrum measured with a proton nuclear magnetic resonance ( ¹ H-NMR) measuring machine.
Sample preparation: 30 mg of resin composition pellets were dissolved in 0.75 ml of d6-DMSO by heating at 60 ° C. for 4 to 6 hours.
Measuring instrument: JEOL JNM ECA-500
Measurement conditions: Measurement temperature: 25 ° C., observation nucleus: 1H, integration number: 64 times, repetition time: 11 seconds Spectral attribution: The spectral attribution measured in dimethylsulfoxide heavy solvent is 0.5 to 1.5 ppm peak for methacrylic acid. , Methyl methacrylate and hydrogen of α-methyl group of 6-membered cyclic anhydride, peak of 1.6 to 2.1 ppm is hydrogen of methylene group of polymer main chain, peak of 3.5 ppm is carboxylic acid of methyl methacrylate The hydrogen of the ester (—COOCH ₃ ), the peak at 12.4 ppm is the hydrogen of the carboxylic acid of methacrylic acid. The peak at 6.5 to 7.5 ppm is hydrogen in the aromatic ring of styrene.

(2) Measurement of Vicat softening temperature It measured based on ISO306. The load was 49N.

(3) Measurement of residual amount of styrene dimer and trimer when the total content of styrene monomer unit, methacrylic acid monomer unit, and methyl methacrylate monomer unit is 100% by mass Preparation: After 2.0 g of the resin composition was dissolved in 20 ml of methyl ethyl ketone, 5 ml of methanol containing a standard substance was further added and dissolved.
Measurement conditions Equipment: Gas chromatography GC-17Apf manufactured by Shimadzu Corporation
Column: DB-1 (100% dimethylpolysiloxane) 30 m,
Film thickness 0.1μm, 0.25mmφ
Column temperature: 100 ° C.-2 minutes → 5 ° C./minute→260° C.-5 minutes Inlet temperature: 200 ° C.
Detector temperature: 200 ° C
Carrier gas: Nitrogen

(4) Measurement of content of styrene monomer when total content of styrene monomer unit, methacrylic acid monomer unit and methyl methacrylate monomer unit is 100% by mass Sample preparation: Resin composition 1.0 g of the product is dissolved in 25 ml of dimethylformamide containing a standard substance Measurement conditions Equipment: Gas chromatography GC-14Bpf manufactured by Shimadzu Corporation
Column: SUS 3mmφ × 3m (packed column)
Filler: Liquid phase → PEG-20M 25%
Carrier → Chromosorb W (AW) 60-80 mesh Column temperature: 110 ° C.
Inlet temperature: 220 ° C
Detector temperature: 220 ° C
Carrier gas: Nitrogen

(5) Measurement of weight average molecular weight and Z average molecular weight Sample preparation: Dissolve about 0.05% by mass of resin composition in tetrahydrofuran Measurement conditions Equipment: TOSHOH HLC-8220GPC
(Gel permeation chromatography)
Column: super HZM-H
Temperature: 40 ° C
Carrier: THF 0.35 ml / min
Detector: RI, UV: 254 nm
Calibration curve: Use of standard PS made by TOSOH

(6) aliphatic primary alcohols in the resin composition sample preparation: dissolve the resin composition 0.5g of methyl ethyl ketone 20ml measurement conditions instrument: Shimadzu Seisakusho Ltd. Gas chromatography GC2010
Column: DB-WAX 30 m, 0.25 mmφ, df = 0.5 μm
Temperature: 100 ° C. → 5 ° C./min→130° C. → 10 ° C./min→180° C.-12 min → 20 ° C./min→220° C.-20 min

[Injection molding characteristics and injection molded product characteristics]
(7) Measurement of Charpy impact strength The Charpy impact strength was measured without a notch in accordance with ISO179.
(8) Measurement of tensile yield stress It measured based on ISO527-1.

(9) Judgment of mold contamination Using a 150 x 150 x 2.5 mm strip mold, a short shot was made at the time of injection molding with a filling time of 5.0 seconds. After completion of 70 shots, the injection molding is stopped for 15 minutes, the mold is cooled, the mold surface corresponding to the tip of the molded body is visually observed, and the mold is molded up to 700 shots while confirming the dirt on the mold. Repeated. Mold fouling was determined by the following method.
：: No mold contamination after 700 shots ○: Mold contamination occurred after 420 to 630 shots ×: Mold contamination occurred after 350 shots or less
Molding was performed at a mold temperature of 20 ° C. and a resin composition of 260 ° C. Further, when the components of the mold dirt deposits were measured, most of the dimers and trimers of styrene were found to contain a small amount of alcohol kneaded into the resin composition .

[Non-foaming extrusion characteristics and non-foaming extrudate characteristics]
(10) was dissolved gel insolubles measured resin composition 2g of the resin composition in methyl ethyl ketone 20 ml, a centrifuge of the 43000G, and centrifuged 19000 rpm, 60 min, after discarding the supernatant, the residual liquid Further, 20 ml of methyl ethyl ketone was added, and the same operation was repeated (centrifugation at 19000 rpm for 60 minutes). After the supernatant was discarded, the remaining liquid was dried at 150 ° C. for 30 minutes, and further dried at 215 ° C. under a reduced pressure of 3 kPa for 30 minutes.
(Gel insoluble matter) = (Remaining amount after heating (unit g)) / 2 (unit g) × 100 (%)
Was used to calculate the gel insoluble matter.

(11) Appearance determination of non-foamed extruded sheet After extruding a sheet for 3 hours continuously with a 30 mmφ short shaft sheet extruder, 5 sheets of 10 cm × 20 cm size were cut out from a 0.3 mm thick sheet, and 5 sheets The number of gels, which are foreign matters having an average diameter of (major axis + minor axis) / 2 of 0.5 mm or more, was counted, and the appearance was determined by the following method.
◎: Number of gels is 2 or less ○: Number of gels is 3-9 points ×: Number of gels is 10 points or more

(12) Y. Measurement of I (Yellow. Index) An injection molding machine produced a plate-like molded product having a thickness of 2.5 mm, and a color difference / turbidity measuring machine COH-300A manufactured by Nippon Denshoku Industries Co., Ltd., compliant with JIS K7105. And measured.

(13) Odor determination at die outlet At the time of sheet extrusion with a 30 mmφ short shaft sheet extruder, the odor at the die outlet was confirmed and determined according to the following criteria.
○: Almost no odor ×: Odor

[Foamed extrudate characteristics]
(14) Measurement of waist strength of tray container FIG. 1 is a diagram illustrating a method of measuring the waist strength of a tray container in an example. The foamed extruded sheet foamed by 7.3 times was vacuum-formed into the tray container shown in FIG. 1, and the waist strength (N) was measured. The size of the tray container is 10 cm long, 15 cm wide, and 2 cm deep. Compressed from the side of the tray, the maximum load was used as waist strength.

(15) Appearance determination of foamed extruded sheet The surface roughness of the foamed extruded sheet was visually determined.
○: The rough surface of the sheet is known. ×: The rough surface of the sheet is not known.

[Example 1]
76.9 parts by mass of styrene, 5.4 parts by mass of methacrylic acid, 2.7 parts by mass of methyl methacrylate, 15.0 parts by mass of ethylbenzene, 2,2-bis (4,4-ditertiary butyl peroxycyclohexyl) propane 0 .02 parts by mass of the polymerization raw material composition liquid into a polymerization apparatus comprising a fully mixed reactor having a capacity of 4 liters and then a 2 liter laminar flow reactor at a rate of 1.2 liters / hour, A resin composition was prepared by successively supplying the devolatilizer continuously connected to a single-screw extruder for removing volatile components such as unreacted monomers and polymerization solvents. The polymerization reaction conditions in the polymerization step were a polymerization temperature of 122 to 130 ° C. for the complete mixing reactor and a temperature of 125 to 145 ° C. for the laminar flow reactor. The devolatilized unreacted gas was condensed by a condenser through which a refrigerant at −5 ° C. was passed and recovered as an unreacted liquid. The polymer content in the final polymerization solution was measured by (sample weight after drying / sample weight before drying × 100%) after drying the polymer solution at 215 ° C. under a reduced pressure of 3 kPa for 30 minutes. %Met. Resin pellets obtained by extruding the final polymerization liquid into a pellet are put into a short-shaft extruder and kneaded with an aliphatic primary alcohol of the type shown in Table 1, and the styrene-methacrylic acid-methyl methacrylate resin of the present invention. A composition was obtained. The alcohol content (mass%) in the resin composition shown in Table 1 was quantified by gas chromatography. In addition, as an isoaliphatic primary alcohol in Table 1, a product (Fine Oxocol 180) manufactured by Nissan Chemical Co., Ltd. was used.

Using the obtained resin composition , non-foamed extrudates (non-foamed extrudate sheets) and foamed extrudates (foamed extrudate sheets and tray containers as molded articles) were prepared and evaluated for physical properties and the like. As for the non-foamed extruded sheet, a sheet having a thickness of about 0.3 mm was produced using a 30 mm short-axis extruder with the temperature of the resin melting zone set at 220 to 250 ° C. while reducing the pressure from the vent to 3 kPa with a vacuum pump. For foamed extruded sheets and tray containers, talc (average particle size 1.3 μm) is used as a foam nucleating agent for 100 parts by mass of the obtained resin composition using an extrusion foaming machine equipped with a circular die having a diameter of 150 mm. 0.12 parts by mass and 3.5 parts by mass of liquefied butane as a foaming agent were added to produce a foamed extruded sheet (expansion ratio: 7.5 times). The temperature of the resin melting zone was adjusted to 210 to 240 ° C, the rotary cooler temperature was 145 to 185 ° C, and the die temperature was adjusted to 165 ° C. A foamed tray container having a shape shown in FIG. 1 was produced by vacuum forming using the obtained foamed extruded sheet. Table 1 shows the evaluation results of the properties and physical properties of the non-foamed extrudate and the foamed extrudate.

[Examples 2 to 6 and Reference Example 7]
Table 1 resin composition properties shown (resin, styrene monomer content in the resin composition, the total content of dimers and trimers of styrene, molecular weight, and alcohol content) so that the The conditions were adjusted. Table 1 shows the evaluation results of the properties and physical properties of the non-foamed extrudate and the foamed extrudate.

[Comparative Examples 1-2]
Table 1 resin composition properties shown (resin, styrene monomer content in the resin composition, the total content of dimers and trimers of styrene, molecular weight, and alcohol content) so that the The conditions were adjusted. Note that methyl methacrylate was not used as a polymerization raw material. Production and evaluation of a non-foamed extruded sheet and a foamed extruded product were carried out in the same manner as in Example 1. Table 1 shows the evaluation results of the properties and physical properties of the non-foamed extrudate and the foamed extrudate.

[Comparative Example 3]
Table 1 resin composition properties shown (resin, styrene monomer content in the resin composition, the total content of dimers and trimers of styrene, molecular weight, and alcohol content) so that the The conditions were adjusted. Production and evaluation of a non-foamed extruded sheet and a foamed extruded product were carried out in the same manner as in Example 1. The total content of styrene dimer and trimer in the resin composition was as high as 0.80% by mass. Table 1 shows the evaluation results of the properties and physical properties of the non-foamed extrudate and the foamed extrudate.

[Comparative Example 4]
Table 1 resin composition properties shown (resin, styrene monomer content in the resin composition, the total content of dimers and trimers of styrene, molecular weight, and alcohol content) so that the The conditions were adjusted. Production and evaluation of a non-foamed extruded sheet and a foamed extruded product were carried out in the same manner as in Example 1. In addition, the monomer content of styrene in the resin composition was as high as 900 ppm. Table 1 shows the evaluation results of the properties and physical properties of the non-foamed extrudate and the foamed extrudate.

The styrene-methacrylic acid-methyl methacrylate resin composition of the present invention is excellent in heat resistance, appearance, mechanical strength, and moldability. Non-foamed and foamed extruded plates and extruded sheets using this resin composition, as well as molded products by secondary processing thereof, for example, molded products by injection molding or the like, can be obtained. Furthermore, the styrene-methacrylic acid-methyl methacrylate resin composition of the present invention can be widely used in applications such as electrical product parts, toys, sundries, daily necessities, and various industrial parts, and plays an important role in the industry.

Claims (6)

When the total content of the styrene monomer unit, the methacrylic acid monomer unit, and the methyl methacrylate monomer unit is 100% by mass, the content of the styrene monomer unit is 69 to 92% by mass, The content of the acid monomer unit is 6 to 16% by mass, the content of the methyl methacrylate monomer unit is 2 to 15% by mass, and the total of the residual amount of the dimer and trimer of styrene is A styrene-methacrylic acid-methyl methacrylate resin composition having a styrene monomer content of 0.6 mass% or less and a residual amount of styrene monomer of 700 ppm or less,
A primary alcohol aliphatic number 14 or more carbon containing 0.02 to 1.0 wt%, a styrene - methacrylic acid - methyl methacrylate resin composition. The weight average molecular weight (Mw) is 100,000 to 350,000, and the ratio (Mz / Mw) of the Z average molecular weight (Mz) to the weight average molecular weight (Mw) is 1.6 to 3.5. The styrene-methacrylic acid-methyl methacrylate resin composition described in 1 . The styrene-methacrylic acid-methyl methacrylate resin composition according to claim 1 or 2, wherein the aliphatic primary alcohol having 14 or more carbon atoms is an isoaliphatic primary alcohol having a freezing point of -10 ° C or lower. The non-foaming extrusion sheet formed using the styrene-methacrylic acid-methyl methacrylate resin composition as described in any one of Claims 1-3. The foaming extrusion sheet | seat formed by using the styrene-methacrylic acid-methyl methacrylate resin composition as described in any one of Claims 1-3.   A molded article formed by using the non-foamed extruded sheet according to claim 4 or the foamed extruded sheet according to claim 5.

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