JPH0616886A - Heat-resistant thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain a thermoplastic resin compsn. which is excellent in heat resistance, impact strength, tensile strength, and mold release characteristics and does not become light-colored even when kept standing at a high temp. and then returned to room temp. by compounding a thermoplastic resin compsn. with a specific compd. CONSTITUTION:20-90wt.% thermoplastic copolymer comprising 30-70wt.% arom. vinyl compd. units, 5-50wt.% vinyl cyanide units, and 20-50wt.% N-substd. maleimide units is compounded with 10-80wt.% thermoplastic graft copolymer compsn. which comprises a copolymer consisting of the arom. vinyl comd. units and the vinyl cyanide units and a graft copolymer obtd. by grafting the arom. vinyl compd. and the vinyl cyanide compd. onto a rubber component having a glass transition point of 25 deg.C or lower and has a content of the rubber component of 10-70wt.%, a content of the arom. vinyl units of 40-90wt.%, and a content of the vinyl cyanide units of 10-60wt.%, giving a thermoplastic resin compsn. having a content of the maleimide units of 5-25wt.%, a content of the rubber component of 5-25wt.%, and a grafting ratio of 40-80wt.%. 100 pts.wt. the resulting compsn. is compounded with 0.05-1.5 pts.wt. compd. of the formula (wherein R1 is 2-14C alkyl; R2 and R3 are each 1-6C alkyl; and R4 and R5 are each 8-21C alkyl).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel heat-resistant thermoplastic resin composition, more specifically, it has excellent heat resistance, high mechanical strength and high practical impact resistance, and is excellent in injection molding. It is possible to provide molded products that exhibit releasability and that do not become light-colored or whiten even after being left in a high-temperature atmosphere and then returned to room temperature.For example, for parts of automobiles, office equipment, electrical products, etc. The present invention relates to a heat resistant thermoplastic resin composition suitable as a material.

[0002]

2. Description of the Related Art In recent years, in the fields of automobiles, office equipment, electric appliances, etc., for the purpose of weight saving and energy saving,
In particular, it has been attempted to resinize a part of the sheet metal.
ABS resins have a good balance of physical properties such as impact resistance and mechanical strength and workability, and also have excellent chemical resistance and appearance, and are widely used for the above applications. However, general ABS
A resin composition using a resin and an ABS resin is inferior in heat resistance and cannot be used in applications requiring heat resistance. In order to solve this problem, ABS
A method of improving the heat resistance of the copolymer by introducing an N-substituted maleimide unit into the resin has been considered. For example, U.S. Pat. No. 3,652,726 and JP-A-3-205411 disclose examples using N-arylmaleimide.

On the other hand, when a thermoplastic resin is mixed with a lubricant such as ethylene bis-stearyl amide (hereinafter abbreviated as EBS), the mold release property from the mold is improved when the thermoplastic resin is injection molded. This is well known.

However, a thermoplastic copolymer of styrene, acrylonitrile and N-substituted maleimide,
A thermoplastic resin composition comprising a thermoplastic graft copolymer obtained by grafting a rubber component having a glass transition temperature of 25 ° C. or lower with styrene and acrylonitrile is 100 ° C. to 140 ° C.
When left at room temperature after being left in a high temperature atmosphere of ℃, the problem of lightening (whitening) occurs (Japanese Patent Application No. 3-352930,
Japanese Patent Application No. 3-356835), especially when injection molding the above thermoplastic resin composition, when a lubricant such as EBS is blended in order to improve the mold releasability from the mold, lightening may occur. There was a drawback that it became extremely large.

On the other hand, Japanese Patent Application Laid-Open No. 4-110341 discloses a technique for improving moldability while maintaining heat resistance by adding a carboxylic acid amide wax having a softening point of 180 ° C. or higher to ABS resin. Has been done. However, in the above patent, there is no disclosure about a method of improving the heat resistance to balance the impact resistance and the rigidity (tensile strength) practically and obtaining a resin composition without lightening.

[0006]

That is, conventionally, it has practically sufficient heat resistance, has both high impact resistance and rigidity, good mold releasability during injection molding, and 100 to 1
It has been extremely difficult to obtain a heat-resistant thermoplastic resin composition that simultaneously satisfies the property that even if it is left in a high temperature atmosphere of 40 ° C. and then cooled to room temperature, it is not lightened. Therefore, the present invention has been made for the purpose of providing a heat-resistant thermoplastic resin composition which simultaneously satisfies the above properties.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the present situation, and as a result, have found that the heat-resistant thermoplastic resin composition shown below can achieve the object of the present invention, leading to the present invention. It was

That is, the present invention relates to a heat resistant thermoplastic resin composition comprising the following (1) and (2).

(1) (A) Aromatic vinyl compound unit 30 to 70
% By weight, vinyl cyanide compound unit 5 to 50% by weight, N
A thermoplastic copolymer comprising 20 to 50% by weight of a substituted maleimide unit: 20 to 90% by weight, and (B) a copolymer of an aromatic vinyl compound unit and a vinyl cyanide compound unit, and an aromatic vinyl compound unit. It is composed of a graft copolymer in which a vinyl cyanide compound unit is grafted to a rubber component having a glass transition temperature of 25 ° C. or less, and the ratio of the rubber component is 10
˜70% by weight, the ratio of aromatic vinyl compound units in the components other than the rubber component is 40 to 90% by weight, and the ratio of vinyl cyanide compound units in the components other than the rubber component is 10%.
~ 60 wt% thermoplastic graft copolymer composition:
10 to 80% by weight, the amount of N-substituted maleimide units contained in the total of components (A) and (B) is 10% by weight or more, and the amount of rubber component is 5 to 25% by weight. 100 parts by weight of a thermoplastic resin composition having a graft ratio of 40 to 80% by weight with respect to the rubber component in the graft copolymer, and (2) a compound represented by the chemical formula (I) 0.05 to 1.5 parts by weight. .

[0010]

[Chemical 2]

(Wherein R ₁ is an alkyl group having 2 to 14 carbon atoms, R ₂ and R ₃ are each independently an alkyl group having 1 to 6 carbon atoms, and R ₄ and R ₅ are each independently carbon atoms. 8 to 21 alkyl groups are shown.) Hereinafter, the present invention will be described in detail.

First, the component (1) will be described. Ingredient (1)
Is composed of the following components (A) and (B).

The component (A) comprises an aromatic vinyl compound unit, a vinyl cyanide compound unit and an N-substituted maleimide unit as essential components. Examples of the aromatic vinyl compound unit include styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, chlorostyrene and the like. These may be used alone or in combination of two or more, and styrene is particularly preferable.
Examples of the vinyl cyanide compound unit include acrylonitrile and methacrylonitrile. These may be used alone or in combination of two or more. Examples of the N-substituted maleimide unit include N-phenylmaleimide, N-methylmaleimide,
Examples thereof include N-cyclohexylmaleimide, which may be used alone or in combination of two or more, and N-phenylmaleimide is particularly preferable.
Further, a monomer unit copolymerizable with the above-mentioned monomer may be copolymerized within a range not impairing the object of the present invention. Examples of these copolymerizable monomer units include unsaturated dicarboxylic acid anhydride units (such as maleic anhydride and itaconic anhydride) and (meth) acrylic acid alkyl esters (such as butyl (meth) acrylate and methyl). (Meth) acrylate, cyclohexyl (meth) acrylate, etc.) and the like.

The content of each unit in this thermoplastic copolymer is 30 to 70% by weight of the aromatic vinyl compound unit,
5-50% by weight of vinyl cyanide compound unit and N-
Substituted maleimide units are selected to be in the range of 20-50% by weight. Aromatic vinyl compound unit is 30% by weight
When it is less than the above range, the fluidity is lowered, the processability is deteriorated, and molding may not be performed in some cases. If it exceeds 70% by weight, the heat resistance is lowered. Vinyl cyanide compound unit,
If it is less than 5% by weight, chemical resistance, coating resistance, etc. may deteriorate.
If it exceeds 50% by weight, workability becomes poor. If the content of the N-substituted maleimide unit is less than 20% by weight, the heat resistance improving effect is not sufficiently exhibited, and if it exceeds 50% by weight, the fluidity is lowered and the workability is deteriorated, and molding cannot be performed in some cases. Sometimes. The thermoplastic copolymer can be produced by a conventionally known method such as a continuous bulk polymerization method, a continuous solution polymerization method, a suspension polymerization method or an emulsion polymerization method.

As the component (B), a copolymer of an aromatic vinyl compound unit and a vinyl cyanide compound unit, and an aromatic vinyl compound unit and a vinyl cyanide compound unit are grafted onto a rubber component having a glass transition temperature of 25 ° C. or lower. It is composed of a graft copolymer. The rubber component has a glass transition temperature (A
According to STMD418), a rubber component having a temperature of 25 ° C. or lower is used. They can be used alone or in combination. Examples of the aromatic vinyl compound unit used for the component (B) include those exemplified for the component (A). These may be used alone or in combination of two or more, and styrene is particularly preferable. Further, examples of the vinyl cyanide compound unit used for the component (B) include those exemplified for the component (A). These may be used alone or in combination of two or more. Furthermore, a monomer unit copolymerizable with these may be introduced into the component (B). In this case, only the graft chain of the rubber component may be copolymerized, only the ungrafted copolymer may be copolymerized, or both may be the same or different types. Good. For example, an N-substituted maleimide unit can be introduced into the graft chain to the rubber component, and a (meth) acrylic acid alkyl ester such as butyl acrylate can be introduced into the copolymer not grafted to the rubber component. The proportion of the rubber component contained in the thermoplastic graft copolymer is in the range of 20 to 75% by weight. If the rubber component is less than this, the impact resistance will be low, and if it is higher than this, the processability will be poor. The proportion of the aromatic vinyl compound unit in the components other than the rubber component is selected to be 40 to 90% by weight. If this ratio is less than this range, the workability will be poor, and if it is large, the chemical resistance will be poor. The proportion of vinyl cyanide compound units in the components other than the rubber component is selected in the range of 10 to 60% by weight. If this ratio is less than this range, the chemical resistance and coating resistance will be poor, and if it is more than this range, the workability will be reduced.

The component (B) may be directly produced by graft-copolymerizing an aromatic vinyl compound unit and a vinyl cyanide compound unit in the presence of the rubber component, for example, by an emulsion polymerization method. Good, in the presence of the rubber component, an aromatic vinyl compound unit, and a vinyl cyanide compound unit, for example, a graft copolymer obtained by graft copolymerization by an emulsion polymerization method, an aromatic vinyl compound unit and The vinyl cyanide compound unit may be a mixture with a copolymer produced by, for example, a continuous bulk polymerization method, a continuous solution polymerization method, a suspension polymerization method or an emulsion polymerization method.

The proportion of each component in the component (1) is selected from the range of 20 to 90% by weight of the component (A) and 10 to 80% by weight of the component (B). If the content of the component (A) is less than 20% by weight, the heat resistance of the heat resistant thermoplastic resin composition is insufficient, and if it exceeds 90% by weight, the fluidity is lowered and the workability is deteriorated, and in some cases, molding is performed. There are things you can't do. (B)
When the content of the component is less than 10% by weight, the impact resistance of the heat resistant thermoplastic resin composition becomes insufficient, and when it exceeds 80% by weight, the fluidity is lowered and the workability is deteriorated, and molding cannot be performed in some cases. There is. The amount of N-substituted maleimide in the whole component (1) is 10% by weight or more. If the amount of the N-substituted maleimide is less than this, the heat resistance becomes low.

(1) The proportion of the rubber component in the component is 5 to 25.
It is necessary to be wt%. If the amount of the rubber component is not within this range, the balance of strength (tensile strength) and impact resistance of the resulting heat-resistant thermoplastic resin composition will be poor.

In the graft copolymer in component (B) in component (1), the graft ratio to the rubber component is 40 to 8
It is necessary to be 0% by weight. If the graft ratio is not within this range, the resulting heat-resistant thermoplastic resin composition will have a poor balance between rigidity (tensile strength) and impact resistance.

Next, the component (2) will be described. Ingredient (2)
Is a compound represented by the chemical formula (I).

[0021]

[Chemical 3]

(Wherein R ₁ is an alkyl group having 2 to 14 carbon atoms, R ₂ and R ₃ are each independently an alkyl group having 1 to 6 carbon atoms, and R ₄ and R ₅ are each independently carbon atoms. Component (2) is 0.05 to 1.5 parts by weight per 100 parts by weight of component (1). If the amount is less than 0.05 parts by weight, the effect of improving the dispersibility of pigment dyes and the like and the mold releasability at the time of injection molding are deteriorated. However, there is a drawback that bleeding out occurs on the surface of the molded product.

The heat-resistant thermoplastic resin composition of the present invention may be added to the raw material of the component (1) in advance, or the component (2) may be added and mixed in the polymerization process, or the component (1) ( It can be prepared by kneading 2) using a known method such as a roll, an extruder, a Banbury mixer, and a kneader. In kneading, if desired, other antioxidants, light stabilizers, ultraviolet absorbers, heavy metal deactivators, flame retardants, pigments, glass fibers, lubricants, plasticizers and other additive components can be added. . Furthermore, a thermoplastic resin other than the present invention can be blended within a range that does not impair the object of the present invention. The additives may be introduced in a step other than kneading, for example, a polymerization step. The heat-resistant thermoplastic resin composition of the present invention thus obtained is molded by a molding method such as injection molding, extrusion molding, blow molding, or vacuum molding.

[0024]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto. Various physical properties were determined as follows.

(1) Heat distortion temperature Specimen thickness 1/4 inch determined according to ASTM D648, Tanzak piece load 18.6 Kg / cm ² (2) Tensile strength Specimen thickness 1 / determined according to ASTM D638 8 inch, dumbbell piece 23 ° C, 50% RH (3) Izod impact strength Test piece thickness 1/4 inch obtained according to ASTM D256, tanzaku piece 23 ° C, 50% RH (4) Melt flow rate according to JISK7210 Obtained 220 ° C., load 10 kg (5) Degree of lightening Injection molded flat plate specimens with a thickness of 1/8 inch
After heat treatment for 3 hours in a hot air dryer at 0 ° C, then at 23 ° C, 50
% Yellowness after standing for 6 hours in a relative humidity atmosphere (hereinafter referred to as YI
Abbreviated) was measured by a color difference meter (manufactured by Suga Test Instruments Co., Ltd.), and the difference from the YI of the flat plate test piece before heat treatment (ΔYI) was obtained.
When ΔYI is positive, it means that the flat plate test piece has turned yellow, and when it is negative, it means that it is lightened.

The following table shows the relationship between ΔYI and the degree of lightening.

[0027]

[Table 1]

(6) Releasability Using an auto shot 100B molding machine manufactured by FANUC,
Resin temperature 260 ℃, mold temperature 60 ℃, length 5cm, width 7
cm, the height was 7 cm, and a box-shaped molded piece having a wall thickness of 1/8 inch was molded to determine the releasability. Judgment criteria are shown below with XX marks.

○ Smooth demolding and no load on the sample △ Demolding is bad, and it can be seen that the sample is loaded when ejected × Poor releasability and the sample is partly galled or deformed (7) Graft The thermoplastic graft copolymer is dissolved in acetone and the insoluble matter is taken out by a centrifuge and dried. The weight of the gel component thus obtained and the weight of the rubber component are calculated by the following equation (2).

[0030]

[Equation 1]

Production Example 1 (A) Component Thermoplastic Copolymer (a
-1) Production of acrylonitrile 18 parts by weight, N-phenylmaleimide 19 parts by weight, styrene 33 parts by weight, ethylbenzene 30
A mixture of 0.01 part by weight and 0.015 part by weight of t-butylperoxyisopropyl carbonate was continuously supplied to the polymerization reactor, and polymerization was performed at 110 to 150 ° C. The polymerization liquid was introduced into an extruder with a vent, the unreacted monomer and the solvent were removed at 260 ° C. and the degree of vacuum of the vent portion was 40 torr, and a thermoplastic copolymer was continuously obtained as pellets. From the thermal decomposition gas chromatographic analysis, the thermoplastic copolymer was a thermoplastic copolymer (a-1) comprising 19% by weight of acrylonitrile unit, 31% by weight of N-phenylmaleimide unit and 50% by weight of styrene unit. .

Production Example 2 Production of Component (B) Component Thermoplastic Graft Copolymer Constituent (b-1) A butadiene rubber latex 4 was placed in a 20 L glass reactor.
5 parts by weight (as solid content), 1.2 parts by weight of rosin emulsifier, 0.15 parts by weight of chain transfer agent, 0.3 parts of chelating agent,
150 parts by weight of pure water was charged so that the total weight became 10 kg, and the temperature was adjusted to 70 ° C. Next, 22 parts by weight of acrylonitrile, 33 parts by weight of styrene, 0.4 parts by weight of a chain transfer agent, and 0.2 parts by weight of a polymerization initiator were added at a constant rate over 7 hours. The emulsion thus obtained was salted out, dehydrated and dried to obtain a thermoplastic graft copolymer. From the results of IR spectrum analysis, the thermoplastic graft copolymer was found to have 46% by weight of butadiene units, 33% by weight of styrene units and 21% by weight of acrylonitrile units, and a graft ratio of 69.
It was a wt% thermoplastic graft copolymer (b-1).

Production Example 3 Production of Component (B) Thermoplastic Graft Copolymer Constituent (b-2) The amount of the continuous transfer agent charged was 0.3 parts by weight, and the chain transfer agent additionally added was 0.8 parts by weight. Graft polymerization was carried out under the same conditions as in Production Example 2 except for the above. The emulsion thus obtained was salted out, dehydrated and dried to obtain a thermoplastic graft copolymer. From the results of IR spectrum analysis, the thermoplastic graft copolymer was found to be composed of 46% by weight of butadiene unit, 33% by weight of styrene unit and 21% by weight of acrylonitrile unit and having a graft ratio of 35% by weight. It was -2).

Production Example 4 Production of Component (B) Component Thermoplastic Graft Copolymer (b-3) 0.1 weight part of chain transfer agent charged and 0.1 weight part of chain transfer agent added additionally. Graft polymerization was carried out under the same conditions as in Production Example 2 except for the above. The emulsion thus obtained was salted out, dehydrated and dried to obtain a thermoplastic graft copolymer. From the results of IR spectrum analysis, the thermoplastic graft copolymer was found to be composed of 46% by weight of butadiene unit, 33% by weight of styrene unit and 21% by weight of acrylonitrile unit, and having a graft ratio of 84% by weight. -3).

Production Example 5 Production of Component (B) Component Thermoplastic Graft Copolymer (b-4) 21 parts by weight of acrylonitrile, 49 parts by weight of styrene, 30 parts by weight of ethylbenzene and 0.015 of t-butylperoxyisopropyl carbonate. A mixed solution consisting of parts by weight was continuously supplied to the polymerization reactor, and polymerization was carried out at 110 ° C. The polymerization liquid was introduced into the extruder with a vent,
The unreacted monomer and the solvent were removed at 40 ° C. and the degree of vacuum of the vent portion at 40 ° C. to obtain a copolymer continuously as pellets. From gas chromatographic analysis, the copolymer was found to have 28% by weight of acrylonitrile unit and 72% by weight of styrene unit.
It was a copolymer (b-4) consisting of

The compound (d) was used as the component (2). The structure of compound (d) is as follows.

[0037]

[Chemical 4]

However, R ₁ =-(CH ₂ ) ₄ -R ₂ , R ₃ =-(CH ₂ ) ₂ -R ₄ , R ₅ = -C ₁₇ H ₃₅ Examples 1 to 4 Formulations shown in Table 1 The components (A) and (B) and the compound (d) are mixed with each other, melt-kneaded with a twin-screw extruder at 280 ° C. to form pellets, and then molded with an injection molding machine at 260 ° C. The degree of lightening (ΔYI) due to heat treatment was measured. The measured values are shown in Table 2.

Comparative Examples 1 to 8 Components (A) and (B) and EBS or compound (d) were mixed in the formulations shown in Table 2 and melt-kneaded at 280 ° C. in a twin-screw extruder to form pellets. After that, it was molded at 260 ° C. with an injection molding machine and various physical properties and the degree of lightening (ΔYI) were measured. The measured values are shown in Table 3.

[0040]

[Table 2]

[0041]

[Table 3]

From Comparative Example 1, it is understood that the mold release property is poor in the system which does not use EBS or the component (2) at all.

From Comparative Example 2, when the compound (d) is 0.01% by weight, the releasability is insufficient.

From Comparative Example 4, in a system having an N-substituted maleimide content of less than 10% by weight, even when EBS is used, lightening does not occur, and the releasability is good, but the heat resistance is low.

According to Comparative Example 5, in the system containing less than 5% by weight of the rubbery polymer, even when EBS is used, lightening does not occur and the releasing property is good, but the impact resistance is insufficient.

From Comparative Example 6, the rubbery polymer content was 25.
In a system in which the amount is more than 10% by weight, even if EBS is used, lightening does not occur and releasability is good, but tensile strength is insufficient.

From Comparative Example 7, the graft ratio of the component (B) was 4
In a system of less than 0% by weight, even if EBS is used, lightening does not occur and the releasability is good, but the impact resistance is low.

From Comparative Example 8, the graft ratio of the component (B) was 8
In the case where the amount exceeds 0% by weight, even if EBS is used, lightening does not occur and the releasability is good, but the impact resistance is low.

From Comparative Example 3, the N-substituted maleimide content was 10% by weight or more, the amount of the rubbery polymer was in the range of 5 to 25% by weight, and the graft ratio was in the range of 40 to 80% by weight. Even in a thermoplastic resin composition, a system using EBS causes remarkable lightening.

On the other hand, as shown in Examples 1 to 4, the N-substituted maleimide content was 10% by weight or more, the amount of the rubber component was in the range of 5 to 25% by weight, and the graft ratio was 4.
By using a specific amount of the compound (d) in a system in the range of 0 to 80% by weight, the balance of heat resistance, impact resistance, and tensile strength is extremely good, and the releasability is also good. Further, it is possible to obtain a heat resistant thermoplastic resin composition in which lightening does not matter.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C08L 33/18 LJN 7921-4J 35/00 LJW 7921-4J 51/04 LKY 7142-4J 55/02 LMC 7142-4J LME 7142-4J

Claims (1)

[Claims] 1. A heat-resistant thermoplastic resin composition comprising the following (1) and (2) (1) (A) aromatic vinyl compound unit 30 to 70% by weight, vinyl cyanide compound unit 5 to 50% by weight, Thermoplastic copolymer consisting of 20 to 50% by weight of N-substituted maleimide units:
20-90% by weight, and (B) a copolymer of an aromatic vinyl compound unit and a vinyl cyanide compound unit, and an aromatic vinyl compound unit and a vinyl cyanide compound unit are grafted onto a rubber component having a glass transition temperature of 25 ° C or less. Made of a graft copolymer, and the proportion of the rubber component is 10 to 70% by weight,
Thermoplastic graft copolymer composition in which the proportion of aromatic vinyl compound units in the components other than the rubber component is 40 to 90% by weight, and the proportion of vinyl cyanide compound units in the components other than the rubber component is 10 to 60% by weight. The amount of the N-substituted maleimide unit contained in the total of the components (A) and (B) is 10% by weight or more, and the amount of the rubber component is 5 to 25% by weight. And 100 parts by weight of a thermoplastic resin composition having a graft ratio of 40 to 80% by weight with respect to the rubber component in the graft copolymer, and (2) a compound represented by the chemical formula (I) 0.05 to 1.5 parts by weight. Department. [Chemical 1] (However, in the formula, R ₁ is an alkyl group having 2 to 14 carbon atoms,
R ₂ and R ₃ are each independently an alkyl group having 1 to 6 carbon atoms,
R _4, R ₅ represents an alkyl group having 8 to 21 carbon atoms independently. )