JP3287734B2 - Manufacturing method of thermoplastic resin with excellent heat resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermoplastic resin having excellent heat resistance, and more particularly to a method for producing a six-membered cyclic anhydride suitable for applications such as light electric parts, industrial parts and resin modifiers. The present invention relates to a method for producing a thermoplastic resin having excellent heat resistance.

[0002]

2. Description of the Related Art Thermoplastic resins, especially methacrylic resins, styrene resins or methyl methacrylate / styrene copolymer resins, are excellent in transparency, moldability, etc., and are therefore used for glazing (inset windows, etc.) and lamps. Automotive and related fields, both indoors and outdoors, as covers, decorations, etc.
It is used in a wide range of fields such as lighting equipment related fields.

However, in the fields related to automobiles and lighting fixtures, the demand for resin materials having a higher heat distortion temperature, good transparency, and good mechanical properties is increasing.
Many considerations have been made to meet this requirement, for example:
It is already known that a material having excellent heat resistance can be produced by copolymerizing methacrylic acid with methyl methacrylate and / or styrene. However, in general, a resin obtained by this method and obtained by copolymerizing methacrylic acid has a high water absorption, so that the heat resistance is reduced due to the water absorption, and a volatile substance is generated by dehydration during the molding process, so that a molded product is produced. The appearance is poor and it has not been put to practical use.

In order to improve this, for example, Japanese Patent Application Laid-Open
Japanese Patent No. 85184 discloses a thermoplastic copolymer having excellent heat-deformability without causing a splash on the surface of a molded article by converting a certain amount of copolymerized ethylenically unsaturated carboxylic acid groups into carboxylic acid anhydride groups. It describes that coalescence can be produced. However, in this method, it is necessary to repeatedly pass the copolymer through an extruder in order to convert a sufficient amount of carboxylic acid groups into anhydrides, and there is a problem that productivity is poor as an industrial process. This method is practically difficult to use.

Japanese Patent Application Laid-Open No. 60-120707 discloses that a copolymer containing a methyl methacrylate unit and an acrylic acid or methacrylic acid unit is continuously reacted in the presence of a solvent, and then the copolymer solution is prepared. There is disclosed a method for producing a colorless and transparent heat-resistant copolymer in which a 6-membered cyclic anhydride unit is formed by supplying an unreacted substance and a solvent by supplying the mixture to a high-temperature vacuum chamber. However, in order to generate a six-membered acid anhydride by this method, it is necessary to increase the residence time of the copolymer in a high-temperature vacuum chamber, which causes a problem such as coloring of the produced polymer. is there.

On the other hand, there is a method of using a ring-closure accelerator to produce a thermoplastic copolymer having excellent heat deformation resistance.
For example, a method using a basic compound as a ring closure accelerator (JP-A-61-254608), a method using a compound selected from organic carboxylate and / or carbonate (JP-A-61-261303), and the like However, since the catalyst used as a ring closure accelerator remains in the thermoplastic copolymer obtained by these methods,
Utilizing the characteristics of the physical properties of the six-membered cyclic anhydride-containing thermoplastic copolymer, when used for the purpose of obtaining a thermoplastic resin having novel physical properties by melt-mixing with other resins, the catalyst of the ring-closure accelerator There are problems such as a reduction in molecular weight of the modified resin due to the influence, which causes a decrease in strength, and a problem of promoting coloring by heating during molding.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for producing a thermoplastic resin which can be industrially advantageously carried out and has excellent heat resistance and excellent melt mixing properties.

[0008]

Means for Solving the Problems The present inventors have developed a method for producing a thermoplastic copolymer containing a six-membered cyclic anhydride unit which is industrially practicable and suitable for melt-mixing with other resins. As a result of intensive research, the molecular weight of the modified resin did not decrease,
The present inventors have found a method for producing a thermoplastic copolymer containing a six-membered cyclic anhydride unit that does not cause coloration by heating during molding, and have accomplished the present invention based on this finding.

That is, according to the present invention, there is provided a heat-resistant copolymer comprising a vinyl monomer unit containing methacrylic acid and / or acrylic acid unit and containing a 6-membered cyclic anhydride unit. In producing a thermoplastic resin, a copolymer represented by the following general formula (1)

[0010]

Embedded image [R ₄ N] ⁺ X ⁻ (1) (wherein, R is an alkyl group having 1 to 8 carbon atoms or 6 carbon atoms)
X is a chlorine atom,
Shows a bromine atom or an iodine atom. )

The present invention can be achieved by a method for producing a thermoplastic resin having excellent heat resistance, characterized by having 0.001 to 2% by weight of a tetraalkylammonium salt represented by the formula (1).

The copolymer comprising a vinyl monomer unit containing a methacrylic acid and / or acrylic acid unit used in the method of the present invention comprises methacrylic acid and / or acrylic acid and another vinyl monomer copolymerizable therewith. There is no particular limitation as long as it is a copolymer composed of a monomer and a methacrylate unit and / or a styrene unit. A copolymer comprising a vinyl monomer unit is preferred. Among these, from the viewpoints of transparency, weather resistance, and the like, a copolymer composed mainly of a methyl methacrylate unit, a methacrylic acid and / or acrylic acid unit, and another copolymerizable vinyl monomer unit if desired. Coalescing is particularly preferred.

[0013] Methacrylic acid and / or
Or the content of the acrylic acid unit is not particularly limited,
3 to 50% by weight of the copolymer, preferably 3 to 40% by weight
It is desirable that If the content of the methacrylic acid and / or acrylic acid units is less than 3% by weight, the thermoplastic resin having novel physical properties by melt mixing with other resins and utilizing the chemical reaction of the six-membered cyclic anhydride units When used for the purpose of obtaining the resin, because the amount of the six-membered cyclic anhydride unit is small,
It is difficult to obtain a thermoplastic resin having novel physical properties, which is not preferable. On the other hand, if the content exceeds 50% by weight, the copolymer is converted into a thermoplastic copolymer containing 6-membered cyclic anhydride units in an extruder to produce a thermoplastic copolymer. Melt extrusion may be difficult due to intermolecular crosslinking, which is not preferable.

As the other vinyl monomers copolymerizable with methacrylic acid and acrylic acid, those generally used as monomers of general-purpose thermoplastic resins can be used. Examples thereof include unsaturated carboxylic acid alkyl esters, Examples thereof include an aromatic vinyl compound, vinyl chloride, and acrylonitrile. Among them, one or more selected from unsaturated carboxylic acid alkyl esters and aromatic vinyl compounds are preferably used.

Examples of the above-mentioned unsaturated carboxylic acid alkyl ester include methacrylic acid ester and acrylic acid ester. Specifically, methyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, n-bornyl methacrylate, Examples include isobornyl methacrylate, cyclohexyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate and the like, and methyl methacrylate is most preferably used.

Examples of the aromatic vinyl compound include styrene and α-methylstyrene, and styrene is most preferably used. The copolymer used in the production of the present invention is a known suspension polymerization, bulk polymerization,
Although it can be produced by a polymerization method such as emulsion polymerization or solution polymerization, a suspension polymerization method and a bulk polymerization method are particularly preferably employed in terms of transparency.

The tetraalkylammonium salt used as a ring closure accelerator in the method of the present invention is represented by the following general formula (1):

[0018]

Embedded image [R ₄ N] ⁺ X ⁻ (1) (wherein, R is an alkyl group having 1 to 8 carbon atoms or 6 carbon atoms)
X is a chlorine atom,
Shows a bromine atom or an iodine atom. )

Specific examples thereof include tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetrapentylammonium bromide, tetrahexylammonium bromide, and tetrahexylammonium bromide. Heptyl ammonium, tetraoctyl ammonium bromide, tetracyclohexyl ammonium bromide, tetracyclooctylammonium bromide, tetracyclodecyl ammonium bromide, tetracyclododecyl ammonium bromide, tetramethyl ammonium chloride, tetraethyl ammonium chloride, tetrapropyl ammonium chloride, Tetrabutylammonium chloride, tetrapentylammonium chloride, tetrahexylammonium chloride, tetraheptylammonium chloride, tetraoctyl chloride Le ammonium, tetra-cyclohexyl ammonium chloride, tetra-cyclooctyl ammonium chloride, tetra-cyclo decyl ammonium chloride, tetra-cyclododecyl ammonium chloride, iodide, tetramethylammonium, tetraethylammonium iodide,
Tetrapropylammonium iodide, tetrabutylammonium iodide, tetramethylammonium iodide, tetrapentylammonium iodide, tetrahexylammonium iodide, tetraheptylammonium iodide,
Examples thereof include tetraoctylammonium iodide, tetracyclohexylammonium iodide, tetracyclooctylammonium iodide, tetracyclodecylammonium iodide, and tetracyclododecylammonium iodide, and especially bromide in terms of the thermal stability of the resin. Tetraethylammonium is preferably used.

The form of these tetraalkylammonium salts may be any of a solid, an aqueous solution and an organic solvent solution, but a solid powder is preferably used from the viewpoint of handleability and the like. As for the method of addition, a part or all of the monomer may be added during the polymerization of the monomer, or may be added to the copolymer and mixed using a mixer. The addition amount is 0.001 to 2% by weight, preferably 0.01 to 1.0% by weight, based on the total amount of the copolymer and the tetraalkylammonium salt. 0.00
If the amount is less than 1% by weight, the intramolecular cyclization reaction of methacrylic acid or acrylic acid is slow, and the rate of conversion into a six-membered acid anhydride in a short-time heat treatment in an extruder is undesirably reduced. On the other hand, if it exceeds 1% by weight,
It is not preferable because the intramolecular cyclization reaction corresponding to the added amount is not promoted, and the intermolecular reaction proceeds to easily generate a crosslinked product.

As the method of performing the heat treatment in the method of the present invention, a known method can be used.
A method using a heating furnace, an extruder, or the like having a vacuum function for removing volatile components is preferably employed. The heat treatment is preferably performed at a temperature of 150 to 350 ° C, preferably 200 to 350 ° C.

According to the present invention, the copolymer comprising a vinyl monomer unit containing a methacrylic acid and / or an acrylic acid unit is added with the above tetraalkylammonium salt in an amount of 0.001 to 0.001.
A heat-resistant thermoplastic resin containing 6-membered cyclic anhydride units by heat treatment in the presence of 2% by weight, and in a preferred embodiment using a vented extruder with a single-screw or multi-screw, for example, A copolymer obtained by adding a desired amount of a tetraalkylammonium salt to a copolymer is supplied to the extruder, and the extruder is fed at 200 to 350 ° C, preferably 260 to 320 ° C.
Heat treatment in the temperature range of In this case, the residence time in the extruder is preferably in the range of 0.5 to 5 minutes. As the pressure during the heat treatment, the intramolecular cyclization reaction proceeds even under normal pressure, and conversion to a six-membered acid anhydride can be performed. It is more preferable because the internal cyclization reaction can be completed and the compound can be completely converted to a six-membered acid anhydride.

[0023]

The present invention will be described below in more detail with reference to examples. The evaluation and measurement methods used in Examples and Comparative Examples are as follows. (1) Method for quantifying 6-membered cyclic anhydride Using a 300 ml autoclave equipped with a stirrer, 15 g of a 6-membered cyclic anhydride-containing thermoplastic resin was charged in 100 ml of ethanol, and heated to 120 ° C to remove the anhydride. After complete conversion to the half ester of carboxylic acid and ethyl ester, the polymer solution was cooled to room temperature and dried under reduced pressure at 60 ° C.

Using a nuclear magnetic resonance spectrometer (GX270 MHz, manufactured by JEOL Ltd.), this sample was subjected to a 4 ppm methylene proton peak based on ethyl ester from a six-membered cyclic anhydride, and a 3.6 ppm methyl ester based on methyl methacrylate methyl ester. The six-membered acid anhydride, methyl methacrylate, and methacrylic acid were quantified based on the integrated intensity of the proton peak and the peak at 12.2 ppm based on carboxylic acid of methacrylic acid.

(2) Method of Measuring Heat Deformation Temperature Measured in accordance with ASTM D-648. (3) Evaluation of Melt Mixing Property A polycarbonate polymer (Taflon I-2200 manufactured by Idemitsu Petrochemical) was used as another resin, and the melt mixture of the resin and the obtained pellets was evaluated by the Izod impact value. (4) Measurement method of Izod impact strength It was measured based on ASTM D-256.

Example 1 In a 75 liter autoclave equipped with a stirrer
After 3 liters of water and 50 g of hydroxycellulose were charged and dissolved, 6800 g of methacrylic acid, 15900 g
g of methyl methacrylate, 90 g of octyl mercaptan and 80 g of lauroyl peroxide were added, and the mixture was stirred under a nitrogen atmosphere, and the internal temperature was raised to 60 ° C. to carry out polymerization. After 4 hours, the temperature was raised to 100 ° C., and polymerization was further performed for 1.5 hours to complete the reaction. Thereafter, the polymer was cooled and taken out, centrifuged, washed with water and washed with water.
Drying was performed at 0 ° C. The composition of the beads was 30 mol% methacrylic acid and 70 mol% methyl methacrylate as a result of NMR analysis.

After mixing the beads with 0.6% by weight of tetraethylammonium bromide by a mixer, the mixture was mixed with a vented 30φ twin-screw extruder (PCM-30 type L / L made by Ikegai).
D = 33.5), and extruded at an extrusion temperature of 280 ° C. and a screw rotation speed of 90 rpm to perform granulation. The polymer composition of the obtained pellets was determined to be N
Analysis by MR measurement showed that 6-membered cyclic anhydride was 21 m
ol%, methacrylic acid was 9 mol%, and methyl methacrylate was 70 mol%. Heat distortion temperature (hereinafter HDT)
Was 135 ° C.

Further, the above-mentioned pellet containing a six-membered ring anhydride and polycarbonate are melt-kneaded with a twin screw extruder at a weight ratio of 5/95, and an injection molding machine (Nippon Steel Works N
70A mold), molding temperature 280 ° C, mold temperature 80 ° C
A predetermined test piece was prepared under the following conditions. The test piece had a good Izod impact value of 15 kg · cm / cm 2.

Example 2 In a 75 liter autoclave equipped with a stirrer
After 3 liters of water and 50 g of hydroxycellulose were charged and dissolved, 4540 g of methacrylic acid and 18160 g were added.
g of methyl methacrylate, 90 g of octyl mercaptan and 80 g of lauroyl peroxide were added, the mixture was stirred under a nitrogen atmosphere, and the internal temperature was raised to 62 ° C. to carry out polymerization. After 4 hours, raise the temperature to 100 ° C,
Polymerization was further performed for 1.5 hours to complete the reaction. Thereafter, the polymer was cooled, taken out, centrifuged, washed with water, and dried at 80 ° C. The composition of the obtained beads was NM
As a result of R analysis, 20 mol% of methacrylic acid, 80 mol
% Methyl methacrylate.

The beads were mixed with 0.6% by weight of tetraethylammonium bromide by a mixer, and a vented 30φ twin-screw extruder (PCM-30L / D manufactured by Ikegai = 33.
Extrusion temperature 280 ° C, screw rotation speed 90 using 5)
Extruded at ppm and granulated. The polymer composition of the pellets was analyzed by NMR measurement using a 6-membered cyclic anhydride quantification method. As a result, 15-mol% of 6-membered cyclic anhydride, 5 mol% of methacrylic acid, and 80 mol of methyl methacrylate were used.
1%. HDT was 123 ° C. Further, the melt mixing property with other resins was evaluated in the same manner as in Example 1. As a result, the Izod impact value was a good value of 13 kg · cm / cm 2.

Example 3 In a 75 liter autoclave equipped with a stirrer
After 3 liters of water and 50 g of hydroxycellulose were charged and dissolved, 4540 g of methacrylic acid, 4540 g
Styrene, 13620 g of methyl methacrylate, 90
g of octyl mercaptan and 80 g of lauroyl peroxide were added, and the mixture was stirred under a nitrogen atmosphere, and the internal temperature was raised to 70 ° C. to perform polymerization. After 4 hours, the temperature was raised to 110 ° C., and polymerization was further performed for 1.5 hours to complete the reaction. Thereafter, the polymer was cooled, taken out, centrifuged, washed with water, and dried at 80 ° C. The composition of the obtained beads was, as a result of NMR analysis, 20 mol% of methacrylic acid, 20 mol% of styrene, and 60 mol% of methyl methacrylate.

To the beads, 0.6% by weight of tetraethylammonium bromide was mixed by a mixer, and a vented 30φ twin screw extruder (PCM-30L / D manufactured by Ikegai = 33.
Extrusion temperature 280 ° C, screw rotation speed 90 using 5)
Extruded at ppm and granulated. The polymer composition of the pellets was analyzed by NMR measurement using a 6-membered ring anhydride quantification method. As a result, glutaric anhydride was 15 mol%, methacrylic acid was 5 mol%, styrene was 20 mol%, and methyl methacrylate was 60 mol%. . HDT is 12
It was 0 ° C. Further, when the melt mixing property with other resins was evaluated in the same manner as in Example 1, the Izod impact value was 12.1.
A good value was shown at 5 kg · cm / cm 2.

Comparative Example 1 In a 75 liter autoclave equipped with a stirrer
After 3 liters of water and 50 g of hydroxycellulose were charged and dissolved, 4540 g of methacrylic acid, 18160 g
g of methyl methacrylate, 90 g of octyl mercaptan and 80 g of lauroyl peroxide were added, the mixture was stirred under a nitrogen atmosphere, and the internal temperature was raised to 62 ° C. to carry out polymerization. After 4 hours, raise the temperature to 100 ° C,
Polymerization was further performed for 1.5 hours to complete the reaction. Thereafter, the polymer was cooled, taken out, centrifuged, washed with water, and dried at 80 ° C. The composition of the obtained beads was NM
As a result of R analysis, 20 mol% of methacrylic acid, 80 mol
% Methyl methacrylate.

The beads were mixed with 0.6% by weight of potassium acetate using a mixer, and the mixture was extruded using a vented 30φ twin screw extruder (PCM-30 L / D = 33.5, manufactured by Ikegai) at an extrusion temperature of 280. C., and extruded at a screw rotation speed of 90 rpm to perform granulation. The polymer composition of the obtained pellets was analyzed by NMR measurement using a method for quantifying a six-membered ring anhydride. Glutaric anhydride was 15 mol%, methacrylic acid was 5 mol%, and methyl methacrylate was 80 mol.
%Met. HDT was 122 ° C. Further, when the melt mixing property with other resins was evaluated in the same manner as in Example 1,
The Izod impact value was 4 kg · cm / cm, and the impact value was considerably reduced. The test piece was colored yellow.

Comparative Example 2 The bead obtained in Comparative Example 1 was treated with sodium methylate 0.1%.
6% by weight was mixed, then extruded and granulated as in Comparative Example 1. The polymer composition of the obtained pellets was analyzed by NMR measurement using a method for quantifying a 6-membered ring anhydride. As a result, 15-mol% of 6-membered ring anhydride, 5 mol% of methacrylic acid, and 80 mol% of methyl methacrylate.
Met. HDT was 122 ° C. Further, when the melt mixing property with other resins was evaluated in the same manner as in Example 1, the Izod impact value was 3.5 kg · cm / cm, and the impact value was considerably reduced. Also, the test piece was colored quite deep yellow.

[0036]

According to the method of the present invention, a thermoplastic copolymer containing a six-membered cyclic acid anhydride unit can be produced in an extremely short time using an extruder or the like in an industrially advantageous manner. Since the thermoplastic resin containing the six-membered cyclic anhydride unit is excellent in transparency, heat resistance, melt mixing property, etc., it is suitably used for various applications such as light electric parts, industrial parts, and resin modifiers. Can be

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-43207 (JP, A) JP-A-63-243903 (JP, A) JP-A-63-163302 (JP, A) JP-A-63-163302 163301 (JP, A) JP-A-62-4704 (JP, A) JP-A-61-254608 (JP, A) JP-A-61-43604 (JP, A) JP-A-60-184504 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 8/00-8/50

Claims (3)

(57) [Claims] 1. A method for producing a heat-resistant thermoplastic resin containing 6-membered cyclic anhydride units by heat-treating a copolymer comprising vinyl monomer units containing methacrylic acid and / or acrylic acid units. the following general formula in the polymer (1) ## STR1 ## _{^{[R 4 N] + X -}} (1) ( wherein, R is the number alkyl group or a C 1 to 8 carbon atoms 6
X is a chlorine atom,
Shows a bromine atom or an iodine atom. A process for producing a thermoplastic resin having excellent heat resistance, wherein 0.001 to 2% by weight of a tetraalkylammonium salt represented by the formula (1) is present. 2. The copolymer mainly comprises methyl methacrylate units, and the content of methacrylic acid and / or acrylic acid units in the copolymer is 3 to 50% by weight.
The production method described in the section. 3. The method according to claim 1, wherein the heat treatment is performed at a temperature of 200 to 350 ° C. in the extruder.