JPS6143604A - Modified copolymer - Google Patents

Abstract

PURPOSE:A transparent polymer, containing methyl methacrylate units, aromatic vinyl compound units, (meth)acrylic acid units, six-membered ring acid anhydride units and six-membered ring imide units in a specific proportion, and having improved mechanical strength and oil and heat resistance and thermal stability. CONSTITUTION:A modified copolymer, obtained by incorporating (A) 29-95wt% methyl methacrylate units with (B) 1-67wt% aromatic vinyl compound units, (C) 1-10wt% (meth)acrylic acid units, (D) 1-48wt% six-membered ring acid anhydride units expressed by formula I (R1 and R2 are H or CH3) and (E) 2- 49wt% six-membered ring imide units expressed by formula II (R3 is H, alkyl, cycloalkyl or aryl) to give 49-96wt% total of the components (A) and (B) and 3-50wt% total of the components (D) and (E) based on the weight of the copolymer, and soluble in dimethylformamide (DMF). USE:Tableware used in electronic ovens, light electrical appliance parts, industrial parts, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel modified copolymer, more specifically, a transparent thermoplastic modified copolymer with excellent mechanical strength, oil resistance, heat resistance and thermal stability. It concerns polymers.

In recent years, there has been a particularly strong demand for resins that have excellent heat resistance, mechanical strength, and oil resistance, are transparent, and are inexpensive for various applications such as microwave tableware, light electrical parts, and industrial parts. BACKGROUND OF THE INVENTION Among currently commercially available resins, polycarbonate resin is known as a colorless and transparent resin with excellent mechanical strength and heat resistance.

However, this resin is not widely used because it is an engineering glass and is expensive.

Among thermoplastic resins, methyl methacrylate resin is commercially available at a relatively low price and has mechanical strength, oil resistance, weather resistance, and outstanding colorless transparency. has the disadvantage of being inferior in heat resistance, particularly in terms of thermal deformability and thermal decomposition.

Therefore, a method of copolymerizing methyl methacrylate and various comonomers has been proposed as a method for further improving the heat resistance without impairing the desirable physical properties of methyl methacrylate resin. By the way, the comonomers used in this case include unsaturated carboxylic acids and unsaturated dicarboxylic anhydrides such as acrylic acid, methacrylic acid, and maleic anhydride;
Aromatic vinyl compounds such as α-methylstyrene are common, but when these comonomers are introduced into a system based on methyl methacrylate, all
It has not been put to practical use because it easily generates gas at a molding temperature of ~260°C and also produces molded products that are inferior in appearance to methyl methacrylate resin.

Under these circumstances, the present inventors have conducted extensive research to improve both the heat deformability and thermal stability of methyl methacrylate resin, and have first attempted to improve the general formula (R8 in the formula) in the molecule. and R8 is a hydrogen atom or a methyl group. The units are secondary derivatives of acrylic or methacrylic acid units.

However, even resins having high heat deformability due to the introduction of six-membered cyclic acid anhydride units have inferior heat resistance compared to polycarbonate, and are not necessarily satisfactory.

Problems to be Solved by the Invention Therefore, the present inventors conducted further research in order to obtain a resin with excellent heat resistance, and converted a part of the six-membered cyclic acid anhydride units into the following general formula: (In the formula, R1 and R2 are a hydrogen atom or a methyl group, and Rs is a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group.)
It has been discovered that a resin with improved heat resistance can be obtained.

Polymers containing this six-membered ring imide unit have already been prepared by reacting homopolymers and copolymers of methyl methacrylate with ammonia or primary amines in an extruder. ), a method of modifying it to a polymer containing a six-membered ring imide unit (Japanese Patent Application Laid-open No. 52-65989
Publication No. 2). However, the polymers obtained by this method have extremely low mechanical strength, and even in the prior art described in the publication, the polymers containing six-membered ring imide units obtained by these methods have very low mechanical strength. It has the disadvantage of being low. Furthermore, a polymer obtained by modifying six-membered cyclic acid anhydride units into six-membered cyclic imide units by a method similar to the method of the present inventors (JP-A-5FJ-71
No. 928) is also known.

However, this polymer has 50 six-membered ring imide units.
On a heavy plate, the content is substantially 80% by weight or more, and although the heat deformation temperature is significantly increased, the mechanical strength is low.

In view of these circumstances, it is an object of the present invention to improve heat deformability by modifying a part of the six-membered cyclic acid anhydride units into six-membered cyclic imide units, and at the same time improve the heat deformability of the methyl methacrylate units. and aromatic vinyl compound units in predetermined amounts, respectively, to improve mechanical strength and fluidity, thereby providing a modified copolymer with comprehensively improved performance.

Means for solving the problem, that is, the present invention provides methyl tetramethacrylate units 29-
95% by weight, (to) 1 to 67% by weight of aromatic vinyl compound units, (b) 1 to 10 acrylic acid or methacrylic acid units
1 to 48% by weight of six-membered cyclic acid anhydride units represented by the general formula (in which R1 and a are hydrogen atoms or methyl groups); R2 is a hydrogen atom or a methyl group, and R1 is a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group. The sum of and (Bl unit and (
A modified copolymer characterized in that the sum of the unit and the Nishi unit is 49 to 96% by weight and 3 to 50% by weight, respectively, based on the weight of the copolymer, and is soluble in dimethylformamide. It provides integration.

In the copolymer of the present invention, the methyl methacrylate unit (gradient unit) is the main monomer unit of the copolymer, and
It plays a role in improving mechanical zero strength and oil resistance, and its content is 29 to 95 weight f with respect to the copolymer.
! in the range of %. If this content is less than 29% by weight, the mechanical strength of the copolymer will decrease, and if it exceeds 95% by weight, the fluidity and thermal stability of the copolymer will decrease when heated.

The aromatic vinyl compound unit, which is the second monomer unit in the copolymer of the present invention, plays a role in improving the fluidity and thermal stability of the copolymer during heating. The content thereof is in the range of 1 to 67% by weight based on the copolymer. If the content is less than 1% by weight, the fluidity and thermal stability during heating of the copolymer will decrease, while if it exceeds 67% by weight, the mechanical strength and oil resistance will decrease.

Furthermore, the total amount of the methyl methacrylate units and aromatic vinyl compound units in this copolymer is in the range of 49 to 96% by weight. If this amount is less than 49 weights, the copolymer becomes brittle, while if it exceeds 96 weights, the heat deformability and thermal stability of the copolymer decrease.

Examples of this aromatic vinyl compound unit include styrene, α-methylstyrene, p-methylstyrene, 2.4-
dimethylstyrene, p-tert-butylstyrene, p
-monomeric units such as chlorostyrene, among which styrene units are the most common.

The acrylic acid or methacrylic acid unit (C1 unit) in the copolymer of the present invention plays a role in increasing the heat deformability of the copolymer, and its content is 1 to 10% by weight relative to the copolymer. %, and if the amount exceeds 10M, gas is generated during injection molding at a temperature of 280° C. or higher, which impairs the appearance of the molded product, which is disadvantageous.

The six-membered cyclic acid anhydride unit (p) unit and the six-membered cyclic imide unit (t) unit in the copolymer of the present invention play a role in increasing the heat distortion temperature and thermal stability, respectively. is larger for the six-membered ring imide unit. Regarding the content of (b) units and west units, the (to) units are 1 to 48% by weight, preferably 1 to 38 units by weight, based on the copolymer.
% range, the units range from 2 to 49% by weight, preferably from 2 to 49% by weight.
in the range of 38% by weight, and the total amount of units and (7) units is 3 to 50% by weight, preferably 10 to 40%]
It is within the range of i quantity. If the total amount is less than 3% by weight, no improvement in heat deformability and thermal stability can be expected;
If the temperature exceeds 1, the heat distortion temperature of the copolymer will be significantly increased, but the mechanical strength will be lowered and the moldability will also be lowered.

The six-membered ring imide unit of the unit (b) is a precursor of a uniform six-membered ring imide unit, and it is necessary that a part or most of it be modified into a four-membered ring unit, and at least co-unit. Unless 2 weight q6 of the polymer is modified into a six-membered ring imide, the thermal deformability of the copolymer will not be improved.

The most common method for quantifying the five types of repeating units IA) to IA) in the copolymer of the present invention is a method using an infrared spectrophotometer. In particular, the methyl methacrylate unit is characterized by absorption at 17!1001-1, and the six-membered cyclic acid anhydride unit utilizes the absorption at 1800cm-' and 1760ax-'.In the six-membered cyclic imide unit, N The -substituted product has a clear absorption at 1670 G-, distinguishing it from the 1730 cm" of the methyl methacrylate unit, while the N-substituted absorption at 1700 cm" is
The methyl methacrylate unit, 173001''''I, is distinct from the methyl methacrylate unit.Therefore, the six-membered ring imide unit is determined using a nitrogen content determination method based on elemental analysis.On the other hand, the acrylic acid or methacrylic acid unit is determined using a nitrogen content determination method based on elemental analysis. Neutralization titration is the most preferred method, and rapid titration with an alcoholic NaOH solution in acetone allows for quantification, distinguishing it from six-membered cyclic acid anhydride units.Also, for the quantification of aromatic vinyl compound units, an infrared spectrophotometer is used. Although it is common, especially when the amount is small, ultraviolet absorption method is used.

In the copolymer of the present invention, ammonia, aliphatic primary amine, aromatic amine, etc. are used to modify six-membered cyclic acid anhydride units into six-membered cyclic imide units. As ammonia, liquid ammonia, ammonia gas, and aqueous ammonia can be used, and as aliphatic primary amines, for example, methylamine, ethylamine, D-clobylamine, 0-propylamine, butylamine, and pentylamine are used. , hexylamine, cyclohexylamine, allylamine, etc., and these can also be used as an aqueous solution. Examples of aromatic amines include aniline and 0-toluidiy.

p-Toluidine, 0-chloroaniline, p-chloroaniline, 2-4. +5-) V-chloroaniline, α-su7thylamine, β-su7thylamine, etc., and also include benzylamine, D-~, D- or L-α-7enethylamine, β-7enethylamine, etc. be able to. Furthermore, polyamines such as 2-diethylaminoethylamine, hydroxyl and amines such as ingropanolamine can also be used.

For the production of a copolymer containing a six-membered cyclic acid anhydride unit, which is a precursor of the copolymer of the present invention, all conventional radical copolymerization methods can be used, but in particular continuous bulk polymerization method can be used. Alternatively, a continuous solution polymerization method is preferable, and one polymerization reactor is preferably a complete mixing type in order to make the composition of the copolymer as uniform as possible.

In the case of continuous solution polymerization, examples of solvents include toluene,
Aromatic hydrocarbons such as ethylbenzene, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, alkyl or chloroalkyl alcohols having 1 to 6 carbon atoms, ether compounds such as tetrahydrofuran and dioxane, ethylene glycol monoalkyl ethers, etc. is used.

Next, various methods can be used to modify the six-membered cyclic acid anhydride unit into the six-membered cyclic imide unit. For example, in an autoclave, 29 to 95% by weight of methyl methacrylic acid units and 1 to 1 to 10% of aromatic vinyl compound units are added as reaction precursors.
61% by weight, acrylic or methacrylic acid units 1-1Ω
A method in which a copolymer consisting of heavy fikS and 3 to 50% by weight of six-membered anhydride units is prepared, then aqueous ammonia is injected in a solution state to react, and further treated at a temperature of 250°C for 2 hours to imidize. Alternatively, after continuously melting the precursor copolymer using an extruder, aqueous ammonia, cyclohexylamine, azoline, etc. are continuously injected, and then cyclization to imide is performed in a reduced pressure chamber. is used.

The thus obtained copolymer of the present invention is as follows.

There is no inconvenience such as intermolecular crosslinking (gelation), and it is soluble in organic solvents, especially dimethylformamide.
and is completely thermoplastic.

Effects of the Invention The modified copolymer of the present invention is transparent and has a Vicat softening temperature of 1.
It exceeds 20℃, and when the temperature is increased by 10℃/min in heating loss measurement using a thermobalance in a nitrogen stream, 1
It exhibits excellent thermal stability with a weight loss of 300°C or more, and has extremely excellent mechanical strength and oil resistance comparable to polymethyl methacrylate.

EXAMPLES Next, the present invention will be explained in more detail by examples.
The present invention is not limited to these examples in any way.

The method for measuring each physical property is as follows.

Softening temperature: ASTM-D1525 (2
) Tensile strength 2 ASTM-D6313 (3) Bending strength and flexural modulus: ASTM-D790 (4) Heating distortion temperature 2 ASTM-D648 (5) Color tone: Observe the injection molded piece with the naked eye.

(6) Immersion test in boiling water: Pour water into an autoclave, place the injection molded product, and heat it at 100°C for 2 hours. Observe the presence or absence of cloudiness, and measure the water absorption rate based on the increase in weight.

(7) Thermal stability: In nitrogen flow, heating rate 10°C/
It is expressed as the temperature at which the weight loss of the polymer in thermobalance analysis is 1 kg under conditions of 100 min.

Example 1 11 parts by weight of styrene, 9 parts by weight of methacrylic acid.

60 parts by weight of methyl methacrylate, 20 parts by weight of ethylbenzene and 0.1 part by weight of octyl mercaptan.

Prepare a mixed solution consisting of 0.5 z/h
Polymerization was carried out by continuously feeding the mixture into a jacketed complete mixing reactor having an internal volume of 21 cm at a rate of r. As a polymerization initiator 1,
1-tert-butylperoxy-3゜5.5-)
Limethylcyclohexane was used, and the polymerization temperature was 110°C. A polymerization reaction solution having a solid content of 42% by weight was continuously supplied to a high-temperature vacuum chamber to remove unreacted substances and produce a six-membered cyclic acid anhydride. The results of neutralization titration and compositional analysis using an infrared spectrophotometer of this copolymer produced were as follows: 15 styrene units
70% by weight of methyl methacrylate units, 4% by weight of methacrylic acid units, and 11% by weight of six-membered cyclic acid anhydride units.

0.5# of the copolymer obtained as above was shaped into a pellet for 51! Then, 5.0 kg of dimethylformamide was added, stirred to dissolve the entire amount, and then 28% ammonia water containing 0.4 equivalent of ammonia per unit amount of six-membered cyclic acid anhydride was added, and the mixture was heated at 75°C. , treated for 2 hours. The reaction solution was taken out, a polymer was precipitated with n-hexano, and after purification, this polymer was heated at 250°C for 2 hours for 1
The treatment was carried out in a volatilization furnace at 0 torr. The final product was almost colorless and transparent, and as measured by an infrared spectrophotometer, it showed a 1800 ag characteristic of six-membered cyclic acid anhydrides.
-l and 1760G- absorption was observed, and at the same time 1
The formation of a six-membered ring imide was observed from the new absorption at 700cm''. According to the nitrogen content in elemental analysis, the six-membered ring imide unit was 3% by weight. Together with the acid anhydride copolymer as a precursor, Table 1 shows its composition and properties.

Examples 2 and 3 and Comparative Examples The amount of ammonia charged in Example 1 was varied to vary the amount of modification of six-membered cyclic acid anhydride units to six-membered cyclic imide units. In particular, a comparative example in which the amount of ammonia was 0.2 equivalent to the unit amount of six-membered cyclic acid anhydride was used, and in the other cases, a larger amount of ammonia than in Example 1 was used. The other operating methods are exactly the same as in the first embodiment. The composition of each polymer,
The characteristics are shown in Table 1.

Example 4 6 parts by weight of styrene, 22 parts by weight of methacrylic acid.

32 parts by weight of methyl methacrylate, 40 parts by weight of cyclohexanone
A mixed solution consisting of 1 parts by weight and 1 parts by weight of octyl mercaptan L was prepared, and polymerization was carried out in the same manner as in Example 1 except for the following. The result of compositional analysis of the obtained copolymer was 10% by weight of styrene units and 50% by weight of methyl methacrylate units.
, 5 methacrylic acid units and 3 6-membered cyclic acid anhydride units
It was 5% by weight.

The copolymer o, skg obtained as described above was charged in pellet form into a 51 autoclave with 3# dimethylformamide and dissolved, and then 0.3 equivalent of ammonia was added to the six-membered cyclic acid anhydride unit. Aqueous ammonia was charged and the reaction was carried out at 75°C for 2 hours. The reaction product was a colorless and transparent viscous liquid. Next, this liquid is
It was treated in a volatilization furnace at 70° C. and 55 torr for 2 hours. The finally obtained reaction product was slightly yellowish and transparent.

Table 2 shows the results of compositional analysis and other properties compared with those of the acid anhydride copolymer as a precursor.

Example 5 In place of 0 and 3 equivalents of ammonia in Example 4, 0.
The imidization treatment was carried out in the same manner as in Example 4 except for using 3 equivalents of methylamine. The reaction product was slightly yellowish but transparent.

When this N.-methyl-substituted six-membered ring imide was measured using an infrared spectrophotometer, a new absorption was observed at 1670aIr'', and it could be clearly distinguished from the ammonia-based imide. Its properties are shown in Table 2.

Claims (1)

[Scope of Claims] 1 (A) 29 to 95% by weight of methyl methacrylate units,
(B) 1 to 67% by weight of aromatic vinyl compound units, (C)
1 to 10% by weight of acrylic acid or methacrylic acid units, (D
) General formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (R_1 and R_2 in the formula are hydrogen atoms or methyl groups) 1 to 48% by weight of six-membered cyclic acid anhydride units and (
E) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R_1 and R_2 in the formula are hydrogen atoms or methyl groups, R
_3 is a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group) A copolymer consisting of 2 to 49% by weight of six-membered imide units represented by and the sum of (D) units and (E) units is 49 to 96% by weight and 3 to 50% by weight, respectively, based on the weight of the copolymer, and is soluble in dimethylformamide. modified copolymer.