JPH0641493B2 - Method for producing copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Object of the Invention> The present invention relates to a method for producing a copolymer which is excellent in heat resistance and thermal stability and is also excellent in affinity with glass fibers.

The composition (AS-G) obtained by blending styrene-acrylonitrile copolymer with glass fiber has heat resistance, impact resistance, and
It is widely known as a molding material having excellent rigidity and dimensional stability, and is widely used in automobile parts and electric parts.

Further, in order to improve the affinity (adhesiveness) between the glass fiber which is an inorganic substance and the polymer, it has been proposed to modify the polymer with maleic anhydride, and in fact, the mechanical strength and the like are not modified. It is superior to AS-G.

However, a glass fiber-containing resin composition using a maleic anhydride-modified copolymer is inferior in thermal stability and easily thermally decomposes during molding to cause defective phenomena such as foaming and silver streak.

The present inventors, as a result of earnest research in view of the above problems,
By using the unsaturated dicarboxylic acid anhydride and the maleimide compound in combination at a specific ratio, it is possible to obtain a copolymer having more excellent heat resistance and thermal stability without lowering the affinity with the glass fiber. The heading has arrived at the present invention.

That is, in the present invention, the ratio of the maleimide compound (excluding chlorine or bromine-containing compound) (a) and the unsaturated dicarboxylic acid anhydride (b) is 5:95 to 95: by weight.
5 and the total amount of (a) and (b) is 2 to 70% by weight, the aromatic vinyl compound (c) is 30 to 98% by weight, the unsaturated nitrile compound (d) is 0 to 50% by weight and the unsaturated carvone is Acid alkyl ester compound (e) 0 to 50% by weight
Compound consisting of ((a)-(e) total 100% by weight)
Is polymerized by a solution polymerization method, a bulk polymerization method, or a bulk-suspension polymerization method.

<Structure of the Invention> In the present invention, a maleimide compound (however, a chlorine- or bromine-containing compound is excluded, hereinafter simply referred to as a maleimide compound) (a), an unsaturated dicarboxylic acid anhydride (b) and an aromatic vinyl compound (c ) Is an essential component, and the unsaturated nitrile compound (d) and / or the unsaturated carboxylic acid alkyl ester compound (e) can be used together with these compounds (a) to (c).

An important point in the present invention is the weight ratio of each compound used.

That is, the ratio (a) :( b) of the maleimide compound (a) and the unsaturated dicarboxylic acid anhydride (b) is 5:95 to 95: 5, and the total amount of (a) and (b) is 2 to 70% by weight of the total compound weight.

Maleimide compound (a) and unsaturated dicarboxylic acid anhydride (b)
If the ratio is outside the range of 5:95 to 95: 5, the thermal stability or the affinity with glass fiber is not improved. Further, if the total amount (a + b) of these compounds is less than 2% by weight based on all the compounds, heat resistance and affinity with glass fiber are not improved, and if it exceeds 70% by weight, mechanical strength is unfavorable.

From the aspects of heat resistance, thermal stability, mechanical strength and affinity with glass fiber, (a) :( b) is 15:85 to 85:15, and (a) + (b) is 5 to all compounds. It is preferably 60% by weight.

Examples of the maleimide compound (a) include maleimide, N-methylmaleimide, N-ethylmaleimide, Nt-butylmaleimide, N-phenylmaleimide and the like, and one or more of them can be used. N-phenylmaleimide is particularly preferable.

Examples of the unsaturated dicarboxylic acid anhydride (b) include maleic acid anhydride, citraconic acid anhydride, and aconitic acid anhydride, and one or more of them can be used. Maleic anhydride is particularly preferable.

Further, the aromatic vinyl compound (c) in the present invention is 30 to 98% by weight based on the total weight of the compound. When the aromatic vinyl compound (c) is out of this range, heat resistance, heat stability, processability, mechanical strength and hue are poor, which is not preferable. Especially 4
0 to 95% by weight is preferred.

Examples of the aromatic vinyl compound (c) include styrene, α-methylstyrene, α-chlorostyrene, pt-butylstyrene, p-methylstyrene, O-chlorostyrene, p-
Chlorostyrene, 2.5-dichlorostyrene, 3.4-dichlorostyrene and the like can be mentioned, and one or more can be used. Particularly, styrene and α-methylstyrene are added at 5: 95-
It is preferable to use it in a weight ratio of 80:20 from the viewpoint of the balance between heat resistance and workability.

In the present invention, unsaturated nitrile compound (d) and / or
Alternatively, the unsaturated carboxylic acid alkyl ester compound (e) can be used as necessary. The unsaturated nitrile compound (d) is 0 to 50% by weight based on the total weight of the compound. 5
If it exceeds 0% by weight, heat resistance and hue are poor, which is not preferable. It is particularly preferably 0 to 35% by weight. or,
The unsaturated carboxylic acid alkyl ester compound (e) is also 0 to 50% by weight based on the total weight of the compound. If it exceeds 50% by weight, the heat resistance becomes poor, which is not preferable. It is particularly preferably 0 to 40% by weight.

Examples of the unsaturated nitrile compound (d) include acrylonitrile, methacrylonitrile, fumaronitrile, and maleonitrile, and one or more of them can be used. Acrylonitrile is particularly preferable.

Examples of the unsaturated carboxylic acid alkyl ester compound (e) include acrylic acid esters and methacrylic acid esters such as methyl, ethyl, propyl, butyl, benzyl and hexyl, and one or more of them can be used.
Methyl methacrylate is particularly preferable.

The intrinsic viscosity of the copolymer is not particularly limited, but the intrinsic viscosity in a dimethylformamide solution at 30 ° C. is preferably 0.3 to 1.5 from the viewpoint of heat resistance and processability of the copolymer.

As the polymerization method of the copolymer, a solution polymerization method, a bulk polymerization method,
Bulk-suspension polymerization method and the like can be mentioned. A polymerization temperature and auxiliary agents such as a polymerization initiator and a molecular weight modifier can be appropriately selected and used.

There is no limitation on the order of charging each compound into the polymerization system,
In addition to batch charging before the start of polymerization, after charging a part of the compounds, the rest of the compounds may be charged intermittently or continuously depending on the rate of the polymerization reaction.

For the copolymer obtained by the present invention, glass fibers, dyes and pigments, antioxidants, ultraviolet absorbers, lubricants, antistatic agents,
In addition to additives such as fillers, other polymers such as polycarbonate, polyamide, ABS resin, styrene-acrylonitrile copolymer can be blended.

The present invention will be described in more detail with reference to Examples and Comparative Examples. The parts and% indicate parts by weight and% by weight.

Example 1 A reactor equipped with a stirrer 5 was charged with 85 parts of styrene, 0.5 part of benzoyl peroxide, 0.3 part of t-dodecyl mercaptan and 100 parts of methyl ethyl ketone, and N was adjusted while controlling the temperature in the reaction system at 90 ° C. under a nitrogen gas atmosphere. A solution of 7.5 parts of phenylmaleimide, 7.5 parts of maleic anhydride and 200 parts of methyl ethyl ketone was continuously added over 5 hours for polymerization. After the polymerization, the reaction product was added to methanol and the copolymer was recovered.

Example 2 60 parts of styrene, 20 parts of α-methylstyrene, 0.5 part of benzoyl peroxide and 0.2 part of t-dodecyl mercaptan were charged into the reactor used in Example 1 and then N- was added while controlling the temperature at 90 ° C. Phenylmaleimide 17
Parts, 3 parts of maleic anhydride and 300 parts of methyl isobutyl ketone were continuously added over 7 hours for polymerization. After the polymerization, the reaction product was added to methanol and the copolymer was recovered.

Example 3 The reactor used in Example 1 was charged with 50 parts of styrene, 0.05 part of lauroyl peroxide and t-dodecyl mercaptan.
0.4 part was charged, and a solution consisting of 10 parts of N-phenylmaleimide, 5 parts of maleic anhydride, 20 parts of styrene and 5 parts of acrylonitrile was added while controlling the temperature at 70 ° C.
Polymerization was carried out by continuous addition over time. Then, bulk polymerization was performed for another 30 minutes. The polymerization rate at this time was 47%.
200 parts of an aqueous solution containing 0.2 part of hydroxypropylmethyl cellulose was added to the obtained prepolymer to switch to a suspension system. 0.3 parts of lauroyl peroxide,
A solution consisting of 0.1 part of benzoyl peroxide and 10 parts of acrylonitrile was added, and polymerization was carried out at 70 ° C. for 3 hours and then at 90 ° C. for 2 hours. After the polymerization, steam was blown to remove unreacted monomers, followed by dehydration and drying to obtain a beaded copolymer.

Example 4 In the reactor used in Example 1, 30 parts of styrene, 20 parts of methyl methacrylate, 0.5 part of benzoyl peroxide, t
After charging 0.2 parts of dodecyl mercaptan and 100 parts of dimethylformamide, 30 parts of N-phenylmaleimide and 2 parts of maleic anhydride while controlling the temperature at 90 ° C.
A solution consisting of 0 part and 200 parts of dimethylformamide was continuously added over 5 hours to carry out polymerization. After the polymerization, the reaction product was added to methanol to collect a copolymer.

Example 5 50 parts styrene, 0.05 parts lauroyl peroxide and t-dodecyl mercaptan were added to the reactor used in Example 1.
0.3 part was charged, and a solution consisting of 12 parts of N-phenylmaleimide, 3 parts of maleic anhydride, 5 parts of acrylonitrile and 25 parts of methyl methacrylate was continuously added and polymerized for 6 hours while controlling the temperature at 70 ° C. Then, bulk polymerization was performed for another 30 minutes. The polymerization rate at this time was 51%. 0.1 part of hydroxyethyl cellulose and 0.1 part of partially saponified polyvinyl alcohol were added to the obtained prepolymer.
The suspension system was switched to by adding 200 parts of an aqueous solution containing 1 part. A solution consisting of 0.4 part of t-butylperoxy-2-ethylhexanoate and 5 parts of acrylonitrile was added thereto, and polymerization was carried out at 75 ° C. for 3 hours and then at 90 ° C. for 2 hours. Thereafter, a beaded copolymer was obtained in the same manner as in Example 3.

Example 6 15 parts of styrene, 15 parts of α-methylstyrene, 10 parts of acrylonitrile, 45 parts of methyl methacrylate, and 2.2′-azobisisobutyronitrile were added to the reactor used in Example 1.
After charging 0.5 parts and 200 parts of methyl ethyl ketone, a solution consisting of 5 parts of N-phenylmaleimide, 10 parts of maleic anhydride, 0.4 parts of n-dodecylmercaptan and 100 parts of methyl ethyl ketone was added for 5 hours while controlling the temperature at 70 ° C. Was continuously added for polymerization. After polymerization,
The reaction product was added to methanol to recover the copolymer.

Comparative Example 1 85 parts of styrene, 0.5 part of benzoyl peroxide, 0.3 part of t-dodecyl mercaptan and 100 parts of methyl ethyl ketone were charged into the reactor used in Example 1, and then N-phenylmaleimide 15 was added while controlling the temperature at 90 ° C.
5 parts of a solution consisting of 200 parts of methyl ethyl ketone
Polymerization was carried out by continuous addition over time. After the polymerization, the reaction product was added to methanol to collect a copolymer.

Comparative Example 2 The reactor used in Example 1 was charged with 50 parts of styrene, 0.05 part of lauroyl peroxide and t-dodecyl mercaptan.
0.4 part was charged, and while controlling the temperature at 70 ° C., a solution containing 15 parts of maleic anhydride, 20 parts of styrene and 10 parts of acrylonitrile was continuously added over 6 hours for polymerization. Then, bulk polymerization was performed for another 30 minutes. The polymerization rate at this time was 49%. 200 parts of an aqueous solution containing 0.2 part of hydroxypropylmethyl cellulose was added to the obtained prepolymer to switch to a suspension system. Add 0.3 parts of lauroyl peroxide and 0.1 parts of benzoyl peroxide.
And a solution of 5 parts of acrylonitrile are added,
Polymerization was carried out at 0 ° C. for 3 hours and then at 90 ° C. for 2 hours. Less than,
A beaded copolymer was obtained in the same manner as in Example 3.

Comparative Example 3 The reactor used in Example 1 was charged with 60 parts of styrene, 20 parts of α-methylstyrene, 0.5 part of benzoyl peroxide and 0.2 part of t-dodecyl mercaptan, and then N-while controlling the temperature at 70 ° C. Phenylmaleimide 20
And a solution of methyl isobutyl ketone (300 parts) were continuously added over 7 hours for polymerization. After the polymerization, the reaction product was added to methanol to collect a copolymer.

Comparative Example 4 The reactor used in Example 1 was charged with 150 parts of an aqueous solution containing 0.1 part of hydroxypropylmethylcellulose, which was composed of 70 parts of styrene, 30 parts of acrylonitrile, 0.5 part of lauroyl peroxide and 0.4 part of t-dodecyl mercaptan. After adding the solution, polymerization was carried out at 70 ° C. for 6 hours and then at 80 ° C. for 1 hour. Thereafter, a beaded polymer was obtained in the same manner as in Example 3.

Table 1 shows the results of examining the glass transition temperatures of the copolymers obtained in Examples 1 to 6 and Comparative Examples 1 to 4 and the presence or absence of foaming at the time of injection molding at 250 ° C. Further, 20 parts of glass fiber (length: about 3 mm, diameter: about 10 μ) treated with aminosilane was mixed with 80 parts of these copolymers, and a test piece was prepared at 250 ° C. with an injection molding machine to measure physical properties. Is shown in Table 1. The state of close contact with the glass fiber was evaluated by observing the fracture surface of the test piece with a scanning electron microscope.

<Effect of the Invention> The copolymer produced by the method of the present invention has excellent heat resistance, heat stability and impact resistance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C08F 222/40 MNE 7242-4J

Claims (1)

[Claims] 1. A maleimide compound (excluding compounds containing chlorine or bromine) (a) and an unsaturated dicarboxylic acid anhydride (b) in a weight ratio of 5:95 to 95: 5, and The total of (a) and (b) is 2 to 70% by weight, the aromatic vinyl compound (c) is 30 to 98% by weight, the unsaturated nitrile compound (d) is 0 to 50% by weight, and the unsaturated carboxylic acid alkyl ester compound ( e) a compound comprising 0 to 50% by weight (total of 100% by weight of (a) to (e)) is polymerized by a solution polymerization method, a bulk polymerization method or a bulk-suspension polymerization method. Polymer production method.