JPS5911322A - Production of rubber-modified maleimide copolymer - Google Patents

Abstract

PURPOSE:To obtain the titled copolymer having a high heat-distortion temperature and excellent mechanical strength typified by impact strength, by copolymerising a vinyl monomer with a maleimide monomer fed at a rate lower than the consumption rate of the vinyl monomer in the presence of a rubber-like polymer. CONSTITUTION:Copolymerization of a maleimide monomer (e.g., N-phenylmaleimide) with an aromatic vinyl monomer (e.g., a mixture of styrene, acrylonitrile and methyl methacrylate) is carried out in the presence of a rubber-like polymer. In this copolymerization, the maleimide monomer is fed to the polymerization system in which the rubber-like polymer and the vinyl monomer are present at a rate which is lower than the consumption rate of the vinyl monomer to obtain the titled copolymer. Preferably, this copolymer has a rubber-like polymer content of 10-65wt%, and the balance of a monomer component consisting of below 45mol% maleimide monomer and above 55mol% vinyl monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for efficiently producing a rubber-modified maleimide copolymer that has a high heat distortion temperature and excellent mechanical properties as represented by impact strength.

It is known that a maleimide copolymer composed of a maleimide monomer and a vinyl monomer has a high heat distortion temperature and excellent thermal stability (for example, P, 0,
Towny et al., [J, Org.

Ohem, J., Vol. 26, p. 15, published in 1961), but lacks attractiveness as a molding material due to poor mechanical properties, typified by impact strength.

Normally, the impact strength of vinyl polymers is improved by polymerizing vinyl monomers in the presence of rubber-like polymers to obtain so-called rubber-modified vinyl polymers such as H polystyrene and... ■It is well known in the field of general impact-resistant resins such as S resin. However, when applying the above-mentioned rubber modification means to maleimide-based copolymers, due to the fact that maleimide-based monomers have the property of being extremely easy to alternately copolymerize with other ordinary vinyl-based monomers, For a wide range of monomer charge compositions under normal radical polymerization conditions, the molar ratio of maleimide monomer to vinyl monomer is 1:
An alternating copolymer having a composition of 1 is preferentially produced.

Although this alternating copolymer has a high heat distortion temperature, it is brittle and requires extremely high temperatures for melt molding (G, V, P
a5sen and D, Timmermanl[M
akr-omol, Ohem, J, Vol. 78, No. 112
Page, published in 1964), the maleimide copolymer has desirable properties as a molding material even if the maleimide monomer and the vinyl monomer are polymerized in the presence of a rubbery polymer. It is difficult to obtain union.

On the other hand, as another method for obtaining a rubber-modified maleimide copolymer, an unsaturated dicarboxylic acid monomer such as maleinoic anhydride and another vinyl monomer are polymerized in the presence of a rubbery polymer. A method has been proposed (U.S. Pat. No. 3,998,907) in which a rubber-modified copolymer is reacted with ammonia or amines in a suspended state in water to imidize it, but this method also does not cause the imidization reaction. Not only does it take a very long time to process, but the remaining unreacted dicarboxylic acid component impairs the thermal stability of the resulting copolymer, and intermolecular crosslinking reactions occur during the imidization reaction, resulting in an increase in melt viscosity and gelation. Therefore, it is impossible to obtain a rubber-modified maleimide copolymer having sufficiently satisfactory properties.

Therefore, the present inventors have made efforts to efficiently produce a maleimide copolymer that is suitable for melt molding, has a high heat distortion temperature and thermal decomposition temperature, and has excellent mechanical properties such as impact strength. As a result of our investigation, we found that the above objective could be achieved by conducting polymerization in the presence of a rubbery polymer while controlling the supply rate of the maleimide monomer to the polymerization system within a specific range, and by controlling the copolymer composition arbitrarily and uniformly. We have discovered what can be achieved and arrived at the present invention.

That is, in the present invention, when polymerizing a maleimide monomer and an aromatic vinyl monomer in the presence of a rubbery polymer, maleimide monomer is added to the polymerization system in which the rubbery polymer and vinyl monomer exist. The present invention provides a method for producing a rubber-modified maleimide copolymer, characterized in that the copolymerization is carried out by supplying the vinyl monomer at a rate slower than the consumption rate of the vinyl monomer.

The maleimide monomer used in the present invention has the following general formula (1
).

R,R.

I 3 (However, R1, R2, and R3 in the formula each independently represent hydrogen, halogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an aryl group, etc.) Specific examples of maleimide monomers is maleimide, N-methylmaleimide, N-
Ethermaleimide, N-butylmaleimide, N-laurylmaleimide, N-phenylmaleimide)', N-(p-
bromophenyl) maleimitonatka, and two or more of these may be used in combination.

The vinyl monomer copolymerized with the maleimide monomer includes an aromatic vinyl monomer as an essential component, and other copolymerizable vinyl cyanide monomers and (meth)acrylic acid esters. It is a monomer or monomer mixture containing monomers and the like as necessary. Here, the aromatic vinyl monomers include styrene, a-methylstyrene, etc., the vinyl cyanide monomers include acrylonitrile, methacrylonitrile, etc., and the (meth)acrylic acid ester monomers include Examples include methyl methacrylate and methyl acrylate.

Examples of rubber-like polymers used in the present invention include polybutadiene rubber, acrylonitrile-butadiene copolymer comb (NBR), styrene- Diene rubbers such as butadiene copolymer rubber (SBR), acrylic rubbers such as polybutyl acrylate, polybutyl acrylate, and ethylene-propylene-diene rubber (E
PDM), etc.

In the rubber-modified maleimide copolymer of the present invention, the content of the rubbery polymer necessary to develop sufficient impact strength is preferably 5 to 80% by weight, particularly 10 to 65% by weight. Regarding the remaining monomer composition, in order to achieve a high heat distortion temperature and good melt moldability, a maleimide monomer and a vinyl monomer mainly composed of the above-mentioned aromatic vinyl monomer are used. It is desirable that the ratio is 50 mols or less, especially 45 mols or less of the maleimide monomer to 50 mols or more, particularly 55 mols or more of the vinyl monomer, and a homogeneous copolymerization composition. In the polymerization of the present invention, the charged compositions of the rubbery polymer and monomers should be determined so that a copolymer satisfying the above composition can be obtained.

When copolymerizing in the present invention, the rate of supply of the maleimide monomer to the polymerization system in which the rubbery polymer and vinyl monomer are present is set to be substantially lower than the consumption rate of the vinyl monomer. An essential requirement is to control the speed so that it is slow. The consumption rate of the vinyl monomer here refers to the rate at which the vinyl monomer is copolymerized with the maleimide monomer and consumed;
For more details, see vinyl monomers/maleimide monomers/
In a rubber-like polymer system copolymerization reaction, a copolymer of a vinyl monomer and a maleimide monomer and a graft copolymer of a vinyl monomer and a maleimide monomer onto a rubber-like polymer are formed. means the amount of vinyl monomer consumed per unit time. If the feed rate of the maleimide monomer is controlled in this way, the copolymerized amount of the maleimide monomer in the produced copolymer depends on the feed rate, so a desired homogeneous copolymerization ratio can be maintained at all times. It is. Conversely, if the supply rate of the maleimide monomer is set faster than the consumption rate of the vinyl monomer, the concentration of the maleimide monomer in the polymerization system will increase, and as a result, the maleimide monomer and the vinyl monomer will be This is undesirable because an alternating copolymerization composition in which the molar ratio of monomers is 1=1 is formed.

In addition, in order to avoid the formation of such an alternating copolymer composition with a copolymerization ratio (molar ratio) of 1:1, it is desirable to maintain a low concentration of maleimide monomer in the polymerization system. It is necessary to feed the maleimide monomer to the system where the vinyl monomer is present at a feeding rate of 8.

At this time, there are no particular restrictions on the method of supplying the maleimide monomer; either directly or diluted with a solvent such as methyl ethyl keto 7 or a vinyl monomer such as styrene and supplied continuously or intermittently to the polymerization system. method can be adopted.

A major feature of the present invention is that the polymerization method itself is not particularly limited as long as the feed rate of the maleimide monomer and the monomer concentration in the polymerization system are controlled as described above. Therefore, for the copolymerization of the present invention, ordinary suspension polymerization methods, emulsion polymerization methods, bulk polymerization methods, solution polymerization methods, bulk-suspension polymerization methods, etc. can be employed, and conditions such as polymerization catalysts and polymerization temperatures can also be used. It can be carried out according to the polymerization method of vinyl monomers.

By directly melt-extruding the rubber-modified maleimide copolymer obtained by the method of the present invention using an extruder, a molding material with high heat distortion temperature and impact strength and excellent melt moldability can be obtained. Furthermore, the rubber-modified maleimide copolymer of the present invention can be blended with a separately produced copolymer of a maleimide monomer and a vinyl monomer, such as a styrene/N-phenylmaleimide copolymer, to improve impact resistance. can be added, and furthermore, other thermoplastic resins such as styrene/acrylonitrile copolymer (SAN resin), a-methylstyrene/acrylonitrile copolymer, α-methylstyrene/styrene/acrylonitrile copolymer, acrylonitrile/butadiene /Acrylonitrile copolymer (
ABS resin), methyl methacrylate/butadiene/styrene copolymer (MBS resin), polyethylene terephthalate resin, polybutylene terephthalate resin, polyamide resin, polycarbonate resin, and polyphenylene oxide resin to reduce heat distortion temperature and thermal decomposition temperature. It is also possible to improve. There are no restrictions on the mixing method, and mixing can be performed by any commonly used method. The rubber-modified maleimide copolymer of the present invention may also contain conventional additives for plastics, such as stabilizers, lubricants, fibrous reinforcing agents, colorants,
It is also possible to add flame retardants, conductive materials, etc.

The effects of the present invention will be further explained below with reference to Examples and Comparative Examples. The heat distortion temperature in Examples and Comparative Examples is ASTM D-648-56, and the Izot impact strength is A.
Measured according to STM D-256-56 MlthodA. The unmixed melt viscosity was determined using a Koka type flow tester at 0.5 M'; l x 1. 50 for Ovan nozzle
Measurement was performed at 260°C with a load of Kg/cm2 applied. The number of parts represents parts by weight.

Example 1 [Rubber-modified maleimide copolymer (5) to O)
(1) Copolymer (A) Polybutadiene rubber 1.40 K was placed in a polymerization tank with an internal volume of 207 mm equipped with a reflux condenser, a stirrer, and a dropping funnel.
g, styrene 4.84 Kp (46.5 mol) methyl ethyl ketone (solvent) 5 Ky and benzoyl peroxide (
71 g of initiator) was charged and sufficiently dissolved.

Separately, a methyl ethyl ketone solution of 20% by weight of N-phenylmale was prepared and charged into the dropping funnel.

Next, the temperature inside the polymerization tank was maintained at 80° C., stirring was performed, and polymerization was carried out while dropping the N-phenylmaleimide-methyl ethyl ketone solution from the dropping funnel at a rate of 1200 g/hr.

Seven hours after the start of dropping, the polymerization rate reached 88% by weight. At this point, the dropping of the N-phenylmaleimide-methyl ethyl ketone solution was stopped, and a portion of the polymerization reaction solution was collected and analyzed for residual monomers by gas chromatography. is hardly detected, but styrene is detected, and the remaining amount is about 7 s.
o g (7.5 mol). The amount of N-phenylmaleimide supplied up to this point was 1680g (10
6 mol).

From this, it was confirmed that the supply rate of N-phenylmaleimide was slower than the consumption rate of styrene.

About 7100 g of white copolymer (5) was obtained by dropping the obtained polymerization solution into methanol to remove residual styrene and methyl ether ketone. The composition of copolymer (A) was calculated from the elemental analysis values and the polymerization rate, and was found to be 19% by weight of polybutashev, 5% by weight of methylef, and 24% by weight of N-phenylmaleimide.

(2) Copolymer (B) Ethylene-
Propylene-diene rubber (iodine number 24, Mooney viscosity 65, ethylene/propylene-77.6/22.4 (mole ratio), diene component = 5-ethylidene-2-norbornene) 1.48 Kp, steleno 4.74 Kg (45,
6 mol), benzoyl peroxide 15g toluene 5.2K
g was charged and sufficiently dissolved.

Separately, a solution containing 20% by weight of N-phenylmaleimide and 80% by weight of l-toluene was prepared and charged into the dropping funnel.

Next, the temperature inside the polymerization tank was maintained at 80 DEG C., and solution polymerization was carried out while stirring and dropping the N-phenylmaleimide-toluene solution from the dropping funnel at a rate of 890 g/hr.

The polymerization rate reached 91% 10 hours after the start of dropping. At this point, dropping from the dropping funnel was stopped, and a portion of the polymerization solution was collected and analyzed for residual monomers by gas chromatography. As a result, almost no N-phenylmaleimide monomer was detected, and styrene The remaining amount was about 590 g (0.57 mol). The supply amount of N-phenylmaleimide at this time is 1780
g (11.2 mol).

From this, the supply rate of N-phenylmaleimide is
It was confirmed that the consumption rate was slower than that of styrene.

Approximately 7,400 g of a white copolymer was obtained by dropping the polymerization solution into methanol and removing residual styrene and toluene. The composition of the copolymer was calculated from the elemental analysis values and the polymerization rate and was found to be 20% by weight of ethylene-propylene-diene rubber, 56% by weight of methyl ref, and 24% by weight of N-phenylmaleimide.

(3) Copolymer (0) In the same polymerization tank as used for the copolymer, eterenopropylene-diene rubber (iodine number, Mooney viscosity 65
, ethylene/furopylene-77,6/22.4 (mole ratio), diene component: 5-ethylidene-2-norbornene)
1,4K Hastyrene 5.2 Ky (3o, 8 mol), acrylonitrile 10f]Og (18,9 mol), 14 g of benzoyl peroxide, and 5 kg of toluene were charged and sufficiently dissolved. On the other hand, N-methylmaleimide 2
A zero weight toluene solution was prepared and charged into a dropping funnel.

Next, while maintaining the temperature inside the polymerization tank at 80°C and stirring, 875 g/hr of N-methylmaleimide-toluene solution was added.
Solution polymerization was carried out by continuous dropwise addition at a rate of .

The polymerization rate reached 85% 8 hours after the start of dropping.

At this point, dropping from the dropping funnel was stopped, and a portion of the polymerization solution was sampled and analyzed for residual monomer by gas chromatography. Almost no N-methylmaleimide monomer was detected, and styrene and Only acrylonitrile was detected. The remaining amount is 560g of styrene (5,1
mol) and 310 g (5,8 mol) of acrylonitrile
Met. Further, the amount of N-methylmaleimide supplied up to this point was 1400 g (12.6 mol).

This confirmed that the supply rate of N-methylmaleimide was slower than the consumption rate of styrene and acrylonitrile.

The polymerization solution was dropped into methanol to remove residual monomers and toluene to obtain about 6,200 g of white coelectric material (0). The composition of the copolymer ρ calculated from the elemental analysis values and polymerization rate is:
23% by weight of ethylene-propylene-diene rubber, 46% by weight of methylene chloride, 11% by weight of acrylonitrile, and N-
The content of methylmaleimide was 26% by weight.

(4) Copolymer (Dl) To the same polymerization tank used for copolymerization, add 3.54 kg (solid content) of polybutadiene rubber latex and 1.77 mol of styrene (17.0 mol). , Potassium oleate (emulsifier) 200g1 Sodium formaldehyde sulfoxylate 20g1 Sodium ethylenediaminotetraacetate 5g1 Ferrous sulfate 05g1 Sodium phosphate Sgs Deionized water 9 ~ were charged and stirred.

On the other hand, an emulsified solution consisting of 20% by weight of N-n-n-butylmaleimide, 5% by weight of acrylonitrile, 2% by weight of potassium oleate, 0.2% by weight of cumene hydroperoxide, and 72.8% by weight of deionized water was prepared, and the solution was poured into a dropping funnel. I prepared it in.

Next, emulsion polymerization was carried out while maintaining the temperature inside the polymerization tank at 70° C. and continuously adding the above emulsified solution from the dropping funnel at a rate of 490 g/hr while stirring.

The polymerization rate reached 92% 6 hours after the start of dropping.

At this point, dropping from the dropping funnel was stopped, and a portion of the polymerization reaction solution was collected and analyzed for residual monomers by gas chromatography. As a result, almost no N-n-n-butylmaleimide monomer was detected. First, styrene and acrylonitrile were detected. The remaining amount is styrene 158
g (1,5 mol), acrylonitrile 42 g (o
, 8 mol). Also, the amount of N-n-n-butylmaleimide supplied up to this point was 588 g (4.6 mol).
, the amount of acrylonitrile supplied is 147 g (2.8 mol)
Met.

This confirmed that the supply rate of N-n-n-butylmaleimide was slower than the consumption rate of styrene and acrylonitrile.

Aluminum sulfate (coagulant) is added to the emulsion polymerization latex to coagulate it, washed with water, and dried to form a white powdery copolymer (
D) Approximately 5700 g was obtained. Copolymer (DJ composition calculated from elemental analysis values and polymerization rate: 61% by weight of polybutadiene rubber, 28% by weight of methylene chloride, 2% by weight of acrylonitrile, and N-n-n-butylmaleimide N.

% by weight.

(5) Copolymer) Ethylene-
Propylene-diene based comb (iodine number 23, Mooney viscosity [60, ethylene/).

Lopyrene-68.5/31.5 (molar ratio), diene component: 5-ethylidene-2-norbornene 2, 3
4 Kg, styrene 1. 90 Kg (18.
3 moles), benzoyl peroxide 14g 1 toluene 5Kg
, and 5 kg of n-hexane were charged and sufficiently dissolved.

On the other hand, a solution consisting of 20% by weight of gl[N-phenylmaleimide, 40% by weight of toluene, and 40% by weight of n-hexane was prepared and charged into a dropping funnel.

Next, the temperature inside the polymerization tank was maintained at 85 DEG C., and solution polymerization was carried out by dropping an N-phenylmaleimide-toluene-hexane solution from the dropping funnel at a rate of 440 g/hr while stirring.

The polymerization rate reached 88 hours 8 hours after the start of dropping. At this point, dropping from the dropping funnel was stopped, and a portion of the polymerization solution was collected and analyzed for residual monomers by gas chromatography.N-phenylmaleimide was hardly detected, and styrene was detected, and the remaining amount is approximately 3
00g (2.9 mol).

Further, the amount of N-phenylmaleimide supplied up to this point was 704 g (4.4 mol).

This confirmed that the supply rate of N-phenylmaleimide was slower than the consumption rate of styrene.

The obtained polymerization solution was dropped into methanol to remove residual styrene, toluene, and n-hexane, thereby obtaining about 4,600 g of a white copolymer (g). The composition of the copolymer calculated from the elemental analysis values and the polymerization rate was 50% by weight of ethylene-propylene-diene rubber, 65% of styrene, and 15% by weight of N-phenylmaleimide.

(6) Copolymer (g) (for comparison) Remove the dropping funnel from the same polymerization tank used in Example 1, and add 1.2 Kf of polybutadiene rubber and 1.2 Kf of styrene. 8K
gC 1 7. 3 mol), N-phenylmaleimi)”
3.2 Ky (20.1 mol), 12 g of benzoyl peroxide (initiator) and methyl ethyl ketone (solvent)
9. 0 Kg was charged at once and sufficiently stirred to dissolve.

Next, the temperature inside the polymerization tank was raised to 80° C., and stirring was continued while keeping the temperature at that temperature. After 5 hours, the polymerization was stopped by cooling, and a portion of the reaction solution was collected and analyzed for residual monomers using gas chromatography.
00 g (1.9 mol) and 350 g (2.2 mol) of N-phenylmaleimide remained. Approximately 5,600 g of copolymer (g) was separated and recovered from the reaction solution. The composition of the copolymer (T) calculated from elemental analysis values and polymerization rate is 21% by weight of polybutadiene rubber, 2% by weight of styrene.
8% by weight and 51% by weight of N-phenylmaleimide.

(7) Copolymerization holiday...(for comparison) Add 0.0% polybutadiene rubber to the same polymerization tank used in Example 1.
9Kg, styrene 1. 8 Kg (17.3 moles), 20 g of benzoyl peroxide, and 6.0 to methyl ethyl ketone were charged and sufficiently dissolved.

Separately, a solution of 30 parts of N-phenylmaleimide in methyl ether ketone was prepared and charged into a dropping funnel.

Next, the temperature inside the polymerization tank was maintained at 80° C., and while stirring, the above solution was added to 2.8 liters from the dropping funnel at a rate of 9/hr to carry out solution polymerization.

The polymerization rate reached 84% in 4 hours after the start of dropping. At this point, the dropping of the solution was stopped, and a portion of the reaction solution was collected and analyzed for residual monomers by gas chromatography. As a result, N-phenylmaleimide and sterenka were detected.
N-phenylmaleimide 690 g (4.3
mol) and 140 g (1.3 mol) of styrene remained. Also, the supply amount of N-phenylmaleimide at this point is 5.36? (21.1 mol).

From this, it is clear that the supply rate of N-phenylmaleimide was faster than the consumption rate of styrene.

After the reaction was completed, the reaction solution was added dropwise to methanol to remove residual monomers and methyl ethyl ketone to obtain 5200 g of a white copolymer p). The composition of copolymer n calculated from elemental analysis values and polymerization rate was 17% by weight of polybutadiene rubber, 62% by weight of styrene, and 51% by weight of N-phenylmaleimide.

Example 2 (Measurement of physical properties of copolymers) Copolymers (5), (B), (0) produced in Example 1 and copolymers η, 0) produced in Comparative Examples were melt-extruded using an extruder. Thereafter, the physical properties of the test piece obtained by injection molding were measured. The measurement results are shown in Table 1.

Table 1 Copolymers (A) to (0) of the present invention have appropriate heat distortion temperatures and high impact strength. Also, since the melt viscosity is low, it has excellent moldability. On the other hand, copolymers (g) and 1 produced in Comparative Example 1 have high heat distortion temperatures but low impact strength. Molding is difficult because the melt viscosity is still extremely high.

Example 3 (Measurement of physical properties of resin composition) The copolymer produced in Example 1 was mixed with the copolymer shown below, and after melt extrusion using an extruder, injection molding was performed and the physical properties were measured.

Copolymer (a): A copolymer consisting of 60 parts of styrene, 10 parts of acrylonitrile, and 60 parts of N-n-n-butylmaleimide Copolymer (b): A copolymer consisting of 65 parts of styrene and 55 parts of N-phenylmaleimide Polymer (C): A copolymer consisting of 70 parts of styrene and 10 parts of acrylonitrile.Copolymer (d): A copolymer of 70 parts of α-methylstyrene, 5 parts of styrene, and 25 parts of acrylonitrile.Copolymer (e) : Copolymer consisting of 65 parts of α-methylstyrene, 20 parts of methyl methacrylate, and 15 parts of acrylonitrile °°Toyolac 300'': Toshi Co., Ltd. fiABs resin copolymers (a) to (dl and ゛Toyolac 600°.

Table 2 shows the physical properties of the mixture, and Table 6 shows the physical property measurement results of the resin composition obtained by mixing.

Table 2 From the results in Table 2, by mixing the rubber-modified maleimide copolymer obtained by the method of the present invention with other copolymers and resins, it is possible to achieve a balance between heat distortion temperature, impact strength, and melt moldability. It is clear that an excellent resin composition is obtained.

Patent applicant Higashi Shikikai Co., Ltd.

Claims (1)

[Claims] When polymerizing vinyl monomers mainly consisting of maleimide monomers and aromatic vinyl monomers in the presence of rubbery polymers, polymerization in which rubbery polymers and vinyl monomers are present. A method for producing a rubber-modified maleimide copolymer, which comprises supplying a maleimide monomer to the system at a rate slower than the consumption rate of the vinyl monomer to effect copolymerization.