JPH0224345A - Thermoplastic resin composition containing n-substituted maleimide - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in heat resistance, impact resistance and melt flow by adding a specified polyester elastomer to a resin composition comprising a specified copolymer mixture containing an N- substituted maleimide and a specified graft copolymer. CONSTITUTION:The title composition is obtained by adding 5-20 pts.wt. polyester elastomer (A) containing polybutylene terephthalate as hard segments and polytetramethylene glycol or an aliphatic polyester as soft segments to 100 pts.wt. resin composition comprising 40-70% copolymre mixture (B) prepared by mixing 5-60wt.% random copolymer (a) comprising an N-substituted maleimide and an aromatic vinyl compound with 40-95% random copolymer (b) comprising an aromatic vinyl compound, a vinyl cyanide compound and, optionally, a vinyl monomer and 30-60% graft copolymer (C) prepared by grafting an aromatic vinyl compound and a vinyl cyanide compound onto a rubberlike polymer.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a thermoplastic resin having excellent heat resistance, impact resistance, and melt flowability.
The present invention relates to a thermoplastic resin composition containing a substituted maleimide and having excellent heat resistance, impact resistance, and melt fluidity.

[Conventional technology]

A commonly used method for improving the heat resistance of styrene-acrylonitrile copolymers is to replace part or all of styrene with α-methylstyrene. In addition, in order to improve the heat resistance of rubber-modified thermoplastic resins such as ABS resins, we have developed methods using α-methylstyrene as part of the monomers to be grafted, and α-methylstyrene in ABS resins.
- A method of blending so-called heat-resistant AS resins consisting of methylstyrene and acrylonitrile has conventionally been carried out.

. ABS resin containing a large amount of α-methylstyrene has higher heat resistance than regular ABS resin, so it is used as interior material for automobiles and OA equipment, but its heat resistance is still insufficient. do not have. Therefore, attempts have been made to introduce maleic anhydride as another heat resistance improving component, but there has been a limit to the improvement in heat resistance due to insufficient thermal decomposition stability of the resin.

Attempts have also been made to improve the thermal decomposition stability of a copolymer consisting of an aromatic vinyl compound and maleic anhydride using a primary amine such as anilino, and to improve its thermal decomposition stability. The composition is disclosed in Japanese Patent Publication No. 62-8456. On the other hand, compositions of copolymer resins containing N-substituted maleimides and ABS resins are also known, and are exemplified by JP-A-59-232138.

However, in either case, the balance between heat resistance and impact resistance is poor. For example, in order to increase heat resistance, a composite composition of a copolymer containing a large amount of N-substituted maleimide and ABS resin is obtained, and When evaluating the impact resistance, it was found that the impact resistance was insufficient.On the other hand, in order to maintain the impact resistance, when the amount of the copolymer containing N-substituted maleimide was reduced and a composite composition using a large amount of ABS resin was obtained, The problem was that its heat resistance was not as high as that of conventional heat-resistant ABS resins. Furthermore, resins containing a large amount of N-substituted maleimide have low melt fluidity and are therefore unsuitable for manufacturing large molded products such as automobile parts.

[Problem that the invention seeks to solve]

The present inventors have discovered an effective additive based on a thermoplastic resin containing an N-substituted maleimide compound that can improve the impact resistance and melt flowability of a blend composition with an ABS resin without reducing the heat resistance. By searching and studying the following, we attempted to solve the drawbacks that resins containing N-substituted imide compounds tend to have: high heat resistance but low impact resistance and insufficient melt fluidity.

[Means for solving problems]

In order to solve the above-mentioned problems, a copolymer (A) of an N-substituted maleimide and an aromatic vinyl compound and a copolymer (B) of an aromatic vinyl compound and a vinyl cyanide compound were prepared.
) copolymer mixture (I) with ABS resin (I[)
By adding a small amount of polyester elastomer (III) containing polybutylene terephthalate as a hard segment and polytetramethylene glycol or aliphatic polyester as a soft segment to 100 parts by weight of the composition, the high heat resistance characteristic of imide resins can be achieved. The present invention was accomplished by discovering that a new thermoplastic resin can be obtained that has good impact resistance and melt flowability while maintaining properties.

That is, the present invention comprises (1) (a) 40 to 65% by weight of N-substituted maleimide and aromatic
Random copolymer (A) consisting of 35 to 60% by weight of an aromatic vinyl compound, (b) 50 to 82% by weight of an aromatic vinyl compound, 18 to 50% by weight of a vinyl cyanide compound, and a vinyl copolymerizable with these. Random copolymer (B) consisting of 0 to 10% by weight of monomer (A) 5 to 60% by weight, (B) 40 to 60% by weight
Copolymer mixture (I) mixed in a proportion of 95% by weight
and (ii) a graft copolymer (II) obtained by graft polymerizing 20 to 50 weight % of an aromatic vinyl compound and 5 to 20 weight % of a vinyl cyanide compound to 30 to 65 weight % of a rubbery polymer.
) 30 to 60% by weight, copolymer composition 100 consisting of
Based on the weight part: ■ A polyether-ester type or polyester-ester type polyester elastomer containing 60 to 80% by weight of polybutylene terephthalate as a hard segment and 20 to 40% by weight of polytetramethylene glycol or aliphatic polyester as a soft segment. An object of the present invention is to provide an N-substituted maleimide-containing thermoplastic resin composition containing 5 to 20 parts by weight of (I[I) and having excellent heat resistance, impact resistance, and melt flowability.

Each component constituting the resin composition of the present invention will be described below.

First, the random copolymer (A) constituting the copolymer mixture (I) will be described.

The N-substituted maleimide, which is a copolymerization component in the random copolymer (A), is used in an amount of 40 to 65% by weight.

If it is less than 40% by weight, the heat resistance of the random copolymer (A) itself is low, and the heat resistance of the final composition is also low. On the other hand, 6
If it exceeds 5% by weight, the melt fluidity and thermal decomposition stability of not only the copolymer (A) but also the final composition deteriorate.

On the other hand, the aromatic vinyl compound is used in a range of 35 to 60% by weight. If the amount of the aromatic vinyl compound is less than 35% by weight, the fluidity will decrease, and if it exceeds 60% by weight, the heat resistance will decrease, which is not preferable.

The random copolymer (A) is produced, for example, in a solution-type polymer, and the polymerization method is to charge the aromatic vinyl compound and the N-substituted maleimide together into a reaction vessel and then polymerize them, or to polymerize them first. Any method is possible, such as charging the aromatic vinyl compound and a small amount of N-substituted maleimide and then continuously adding the remaining N-substituted maleimide during polymerization. In this case, a radical initiator such as dilauroyl peroxide can be used as the polymerization initiator, and toluene, methyl ethyl ketone, or chloroform can be used as the solvent, but methyl ethyl ketone ( MEK) is particularly preferred. The polymerization temperature can be arbitrarily selected within the range of 70 to 120°C, but to increase the polymerization rate, a high temperature of 100°C or higher is recommended, and to increase the degree of polymerization, a high temperature of 70 to 80°C is recommended.
A low temperature of After polymerization, the dope is devolatilized and dried in a vacuum dryer. After devolatilization, the lumps are pulverized into a fine powder for convenient blending.

Examples of the aromatic vinyl compound used in the present invention include styrene, α-methylstyrene, p-methylstyrene, and the like. Among these, it is particularly preferable to use styrene and α-methylstyrene alone or as a mixture thereof.

Furthermore, as the N-substituted maleimide used in the present invention, at least one monomer selected from N-phenylmaleimide, N-cyclohexylmaleimide, and N-(2,4,6-)ribromo)-phenylmaleimide is used. is preferred.

The solution viscosity [η] of the copolymer (A) is preferably 0.3 to 1.0 when measured in tetrahydrofuran at 30°C. When it is less than 0.3, the impact resistance of the copolymer composition (I) decreases, and the same applies to the final composition. [η] is 1.
When it is 0 or more, the melt fluidity of (I) decreases, which is not preferable.

Next, regarding the random copolymer (B), the aromatic vinyl compound which is a copolymerization component of the random copolymer (B) is 50 to 82% by weight, or 65 to 82% by weight. Vinyl cyanide compound is 18 to 50% by weight
, preferably from 18 to 35% by weight, and from 0 to 10% by weight of the other copolymerizable vinyl monomer. Outside these ranges, the physical properties of the copolymer (B), particularly heat resistance and impact resistance, are unfavorably deteriorated. As the aromatic vinyl compound used in copolymer (B), the same compound as in copolymer (A) can be used. Further, as the vinyl cyanide compound, acrylonitrinopemethacrylonitrile and the like can be used, but acrylonitrile is most preferred.

Copolymer (B) can also be produced by the same solution polymerization method as copolymer (A), or by suspension polymerization. In the case of the suspension polymerization method, a mixture of an aromatic vinyl compound and a vinyl cyanide compound is added to an aqueous solution containing a calcium phosphate dispersant to form a suspension, and then a radical initiator such as penzoylnoe oxide is added under a nitrogen atmosphere. The copolymer (B) can be obtained in the form of beads by polymerizing at 75 to 90°C for about 10 hours using as a polymerization catalyst. Bead-shaped polymers are particularly effective because they are easily mixed with the powdered polymer of copolymer (A). Solution viscosity of copolymer (B) [
η] is 0.5 when measured under the same conditions as copolymer (A).
~1.5 is preferred. If [η] is 0.5 or less, the impact resistance of the copolymer mixture (I) blended with the copolymer (A) will be low, and the impact resistance of the final composition will also be low. Also [η]
If it exceeds 1.5, the fluidity becomes low, which is not preferable.

An example of the copolymerizable vinyl monomer used in the copolymer (B) is methyl methacrylate. If this material is used in an amount of 10% by weight or more, the heat resistance of the copolymer (B) will deteriorate, which is not preferable.

As for the composition ratio of copolymer (A) and copolymer (B) constituting copolymer mixture (I), it is desirable that (A) be 5 to 60% by weight. If (A) is less than 5% by weight, the heat resistance of the final composition will be impaired, and if (A) exceeds 60% by weight, the fluidity and thermal decomposition stability of the final composition will be reduced, which is not preferred.

Next, the graft copolymer (II) will be described.

The graft copolymer (II) is an aromatic vinyl compound 20
to 50% by weight, and 5 to 20% by weight of a vinyl cyanide compound to 30 to 65% by weight of a rubbery polymer. If the mixing ratio of the monomer mixture to be graft-polymerized is outside this range, the blendability with the copolymer mixture (I) will be poor, and the physical properties of the final composition, particularly the impact resistance, will be poor.

If the rubbery polymer content is less than 30% by weight, the impact resistance of the graft copolymer (II) will be low, and the same will be true of the final composition. On the other hand, if it exceeds 65% by weight, the equilibrium impact resistance will increase, but the heat resistance and melt flowability will decrease. As the aromatic vinyl compound and vinyl cyanide compound used in the graft copolymer (II), the same monomers as in the case of the above-mentioned copolymer mixture (I) can be used. Examples of rubbery polymers include polybutadiene rubber, styrene-butadiene copolymer rubber,
Acrylic rubber or ethylene-propylene rubber can be used. The graft copolymer (It) can be produced by a known emulsion polymerization method or solution polymerization method, but in order to obtain a copolymer with a high rubber content, the above monomer mixture is added to a rubbery polymer latex. An emulsion polymerization method for grafting is advantageous.

Finally, polyester elastomer (III) will be described.

The polyester elastomer (III) used in the present invention is a block copolymer consisting of a hard segment of polyester such as polybutylene terephthalate and a soft segment of polyether or polyester such as polytetramethylene glycol or aliphatic polyester. This polyester elastomer (III)
When exemplified by a chemical structural formula, it is represented by the following formula (1) or [2].

The specific structural components generally include a hard segment of polybutylene terephthalate and a soft segment of aliphatic polyether or aliphatic polyester. The physical properties of this copolymer vary significantly by changing the constituent components of each segment, the mutual ratio of segments, and the molecular weight and type of polyether and polyester. The polyester elastomer (III) can be used, for example, with polytetramethylene glycol or with an aliphatic polyester.
-butanediol and dimethyl terephthalate in the presence of a small amount of diamine at 250°C using a titanium-based catalyst.
It can be obtained by removing methanol while heating and stirring at 10.3 mmHg for about 2 hours.

The ratio of polybutylene terephthalate, which is a hard segment, in polyester elastomer (III) is 60
The content is desirably 80% by weight. When the hard segment is 60% by weight or less, polyester elastomer (I
) is undesirable because the heat resistance of the desired final composition is also lowered. In addition, if the hard segment is 80% by weight or more, it will have poor flexibility and moldability.
The final composition also has poor moldability. On the other hand, polyester-
The soft segment of the elastomer (I) is preferably in the range of 20 to 40% by weight. Outside this range, the final composition will have poor heat resistance or moldability.

The composition ratio of copolymer mixture (I) + graft copolymer (I[) in 100 parts by weight to obtain the composition of the present invention is:
The copolymer mixture (1) is preferably 40 to 70% by weight.

When (I) is less than 40% by weight, heat resistance is low and 70% by weight
Exceeding this will reduce the impact resistance of the final composition. In addition,(
The amount of polyester elastomer (III) added to 100 parts by weight of the total amount of I) + (II) is preferably 5 to 20 parts by weight. If the amount is less than 5 parts by weight, both impact resistance and melt flowability will be lower than that of the polyester elastomer (I).
The addition of II) has a poor effect on improving physical properties, and if more than 20 parts by weight is used, the heat resistance of the final composition decreases.

As a method for obtaining the final composition of the present invention, the copolymer mixture (I) prepared by the above-mentioned method and the graft copolymer (
II) at a weight of 40-70% of (I), i.e. (
It) is weighed in a range of 30 to 60% by weight, and then, based on 100 parts by weight of this blend of (I) and (II),
5 to 2 polyester elastomer (I) as a modifier
Weigh out 0 parts by weight and mix it into the blend of (I) and (I[).

These resin blends are finally mixed and granulated in a mixing device arbitrarily selected from a blender, a ronopenig, a kneading extruder, etc. to obtain the desired composition. It is effective to adopt a machine.

Various heat stabilizers, ultraviolet absorbers, additives, etc. can be added during this kneading and extrusion. The present invention will be specifically explained below using examples.

Note that unless otherwise specified, parts or percentages are based on weight.

〔Example〕

1) Production of copolymer (A) The inside of a reactor equipped with a stirrer was replaced with nitrogen, and MEK
100 parts, α-methylstyrene (αMest) 60L
581 parts of N-phenylmaleimide (pMI) and 052 parts of polymerization initiator lauroyl peroxide (LPO) were added all at once. The temperature was raised from the outside using a heating medium while a small flow of nitrogen was flowing. Polymerization was started when the internal temperature reached 75°C, and polymerization was carried out at that temperature for 3.5 hours. pM during polymerization
1 was added at a rate of 10 parts per hour. After the polymerization was completed, the inside was rapidly cooled, and the dope was transferred to a stainless steel container and devolatilized in a vacuum dryer. The block sample after devolatilization was pulverized using a pulverizer.

When this powder sample was analyzed by IR spectrum,
It was found that αMest was 58% and IIMI was 42%. Also, [η] measured in THF at 30°C is 0.
．． It was 50. Table 1 shows the results of a similar experiment with different types and amounts of monomers.

Table-1 Types of copolymer (A) 1) Cyclohexyl cimaleimide 2) N-(2,4,6-toIJ furomo)phenylmaleimide' 2) Production of copolymer (B) Equipped with a stirrer The inside of the reactor was replaced with nitrogen, and 5t7
2 parts, 28 parts of acrylonitrile (An) and 0.35 parts of benzoyl peroxide (BPO) as a polymerization initiator,
A mixture of 0.18 parts of tertiary dodecyl mercaptan (TDM) as a molecular weight regulator was added and stirred well. Next, 100 parts of an aqueous dispersion containing 0.2 parts of a calcium phosphate dispersant and 0.01 parts of sodium dodecyl sulfate as a dispersion stabilizing agent were added to the monomer mixture and stirred at high speed to form a suspension.

Polymerization was started by raising the internal temperature to 75°C, and after being maintained at that temperature for 16 hours, the internal temperature was further raised to 85°C and polymerization was continued for 2 hours. After the dispersant was decomposed with hydrochloric acid, it was filtered, washed with water, and dried to obtain bead-shaped polymers having a particle size of about 0.2 mm.

The yield was 98%. Table 2 shows the contents of copolymers (B) having different polymer compositions produced in the same manner.

Table 2 Types of copolymer (B) 3) Copolymer (II) As the copolymer (II), the resins shown in Table 3 (manufactured by Japan Synthetic Rubber) were used.

Table 3: Type of copolymer (II) 4) Polyester elastomer (III) As the polyester elastomer in the present invention, commercially available resins shown in Table 4 were used.

5) Method for evaluating physical properties The physical properties of the obtained final resin composition were evaluated using the methods shown in Table-5.

Table 5 Method for evaluating physical properties Examples 1 to 4 Copolymer A shown in the above production example (A-1, Example 1)
(A-4, Example 4) and 30 parts of copolymer (B-1) in powder and bead form were triblended in a polyethylene bag, and then copolymer (I
I-1) 40 parts and as a polyester elastomer (I
II), and then added 0% of Irganox 1010 (manufactured by Ciba Geigy) as a heat stabilizer.
．． 22 parts were added and thoroughly triblended in powder form. In this composition, (A-1)/(B-1) = 50150, and (1)/(I + II) = 60/100.

In addition, (In), / (I + I [) = 10/100
It is. This powder blend was prepared using Osaka Seiki's 4Qmm
The mixture was supplied to a vent extruder, and kneaded and extruded at a cylinder temperature of 240°C and a screw rotation speed of gQrpm. Then,
This pellet was molded into a molded specimen for physical property evaluation using a Nisseki Jushi Kogyo injection molding machine. When the molded specimen was evaluated according to the physical property evaluation items described in the previous section, Example 1 in Table 6 was obtained.
As shown in 4 to 4, all the samples had a good balance of heat resistance, impact resistance, and melt fluidity, and the molded specimens had a good appearance with almost no coloration.

Actual - Absolutely 5 This is an example in which 10 parts of polyester elastomer (III) was used for I+n=100 parts in Example 2. The results of evaluating the physical properties of the final composition in this case also showed that, as shown in Table 6, the impact resistance was slightly lower than that of the previous example, but the heat resistance was further improved and it was found to be excellent in terms of physical properties.

Comparative Example 1 This example is a case in which the modifier (III) was not added to Example 1. In this case, (A-1)/(B-1
) =50150, (I)/(I+I[)=60/1
It is 00. This composition was kneaded and extruded, and the physical properties of injection molded products were evaluated. As shown in Table 6, the molded products had high heat resistance, but low impact resistance and melt flowability, and were satisfactory in terms of physical properties. It wasn't something.

Comparative Example 2 This example is an example in which (I[I)c, which is outside the scope of the present invention, was used as the polyester elastomer (I) in Example 1. The composition ratio of the component resins is exactly the same as in Example 1. Physical properties of the molded sample in this case were measured, and as shown in Table 6, although the heat resistance was high, the effect of using the polyester elastomer (I) as a modifier was poor, and the impact resistance and melt fluidity were low.

Comparative Example 3 This is an example in which copolymer (B-2), which is outside the scope of the present invention, was used instead of copolymer (B-1) in Example 1. Although the composition ratio was the same as in Example 2, (II-2) had poor affinity with ABS resin due to its low acrylonitrile content, and as shown in Table 6, the physical properties of the final composition were poor.

Example 6 In this example, as shown in Table 7, 36 parts of (A-2) and (B
29 parts of -1), 35 parts of (II-1), (III
).

This is an example using 15 copies of each. In this case (A-2)
/ (B-1) -55/45, (I) / (I + II) = 55/100, and (I + II) = 1
00 copies), corresponds to 15 copies. As shown in Table 7, the physical properties of the molded specimen of this composition were high in heat resistance, impact resistance, and melt flowability.

Example 7 In this example, (A-4) 25 parts, (B-1) 20 parts, (II
-1) 55 parts and modifier (III), 10 parts, (A-4) / (B-1) = 55.6
/44.4, (I) / (I+II) =45/10
It is 0.

In this case as well, as shown in Table 7, the impact resistance was slightly lower than in Example 4, but the heat resistance was excellent.

Example 8 This example is an example in which 10 parts of (III) as the polyester elastomer in Example 6 was used. In this example, (A-2) / (B-1) = 55/45, (I
) / (I + II) = 65/100. The physical property evaluation results of this composition are shown in Table 7, and the heat resistance, impact resistance, and melt fluidity were well balanced.

Comparative Example 4 This is an example in which (It-2), which is outside the scope of the present invention, was used as the ABS resin in Example 2. The composition ratio is as in Example 2.
However, since the rubber content of (II-2) was low, the impact resistance of the final composition was low as shown in Table 7.

Comparative Example 5 In this example, the type of copolymer was the same as in Example 2, but the blend composition ratio was outside the scope of the present invention. In this case, (A-2)/(B-1) = 50150, but (I)/(1+II) = 30/100. The physical properties of the composition at this time are shown in Table 7. Although the impact resistance was high, the heat resistance was low and the melt fluidity was also low.

Comparative Example 6 In this example, (A-2)/(B-1) = 50150, but (1)/(I+I[) = 90/100, and was carried out outside the scope of the present invention. The physical property evaluation results in this case are shown in Table 7. Although the heat resistance was very high, the impact resistance and melt fluidity were low.

Comparative Example 7 In this example, the type of copolymer was the same as in Example 1, but 30 parts of the modifier (III), which was outside the scope of the present invention, was used. As shown in Table 7, the heat resistance was very low at 189°C.

〔Effect of the invention〕

As a result of the present invention, the problems that conventional imide-modified styrenic resins tend to have, such as high heat resistance but low impact resistance and melt fluidity, have been solved.

Therefore, we supply new resin materials that have the characteristics of styrene resins, such as excellent heat resistance and impact resistance, good moldability, and low cost, as raw materials for chassis parts of OA equipment, automobile exterior materials, etc. It became possible to do so.

Claims (1)

[Claims] 1[1] (a) A random copolymer (A) comprising 40 to 65% by weight of an N-substituted maleimide and 35 to 60% by weight of an aromatic vinyl compound; (b) an aromatic vinyl compound Random copolymer (B) consisting of 50 to 82% by weight, 18 to 50% by weight of a vinyl cyanide compound, and 0 to 10% by weight of a vinyl monomer copolymerizable with these (A) 5 to 60% by weight %, (B) a copolymer mixture formed by mixing in a proportion of 40 to 95% by weight (I) 40 to 70%
[2] 20-50% by weight of aromatic vinyl compound, 5-20% by weight of vinyl cyanide compound, 30-65% by weight of rubbery polymer.
Graft copolymer (I
I) 30-60% by weight of the resin composition, [3] 60-80% by weight of polybutylene terephthalate as the hard segment, and 20-80% of polytetramethylene glycol or aliphatic polyester as the soft segment. An N-substituted maleimide-containing thermoplastic with excellent heat resistance, impact resistance, and melt flowability, comprising 5 to 20 parts by weight of polyether/ester type or polyester/ester type polyester elastomer (III) containing 40% by weight. Resin composition. 2 N-substituted maleimide is N-phenylmaleimide,
N-cyclohexylmaleimide and N-(2,4,6-
The N-substituted maleimide-containing thermoplastic resin composition according to claim 1, which is at least one selected from tribromo) phenylmaleimide. 3. The N-substituted maleimide-containing thermoplastic resin composition according to claim 1, wherein the aromatic vinyl compound is styrene, α-methylstyrene, or a mixture thereof.