HEAT RESISTANCE RESIN COMPOSITION AND INJECTION MOLDED BODY THEREOF

Abstract

A heat resistant resin composition which does not cause stringing when performing fusion-bonding using heated plates. A heat resistant resin composition, including: a maleimide-based copolymer; and at least one resin selected from the group including: ABS resin, ASA resin, AES resin, and SAN resin; wherein: the heat resistant resin composition has a ratio G′/G″ of storage modulus (G′) to loss modulus (G″) measured in accordance with JIS K 7244-10 under conditions of 240° C. at an angular velocity of 0.63 rad/s is 0.30 or more and 1.00 or less.

Claims

1. A heat resistant resin composition, comprising: a maleimide-based copolymer; and at least one resin selected from the group consisting of: ABS resin, ASA resin, AES resin, and SAN resin; wherein: the heat resistant resin composition has a ratio G′/G″ of storage modulus (G′) to loss modulus (G″) measured in accordance with JIS K 7244-10 under conditions of 240° C. at an angular velocity of 0.63 rad/s is 0.30 or more and 1.00 or less.

2. The heat resistant resin composition of claim 1, wherein the maleimide-based copolymer is contained by 5 to 40 mass %, and the resin is contained by 60 to 95 mass %.

3. The heat resistant resin composition of claim 1, wherein the maleimide-based copolymer comprises 40 to 60 mass % of an aromatic vinyl monomer unit and 60 to 40 mass % of a maleimide-based monomer unit.

4. The heat resistant resin composition of claim 1, wherein a melt mass flow rate of the heat resistant resin composition measured in accordance with JIS K 7210 under conditions of 220° C. and 10 kg is 5 to 30 g/10 min.

5. The heat resistant resin composition of claim 1, wherein a Vicat softening temperature of the heat resistant resin composition measured in accordance with JIS K-7206 is 105° C. to 130° C.

6. An injection molded body molded by using the heat resistant resin composition of claim 1.

7. The injection molded body of claim 6 used as an interior material or an exterior material of an automobile.

Description

EXAMPLE

[0091] Hereinafter, detailed explanation is provided with reference to Examples. However, the present invention is not limited to the following Examples.

<Production Example of Maleimide-Based Copolymer (A-1)>

[0092] To an autoclave having a capacity of about 120 liters equipped with an agitator, 20 parts by mass of styrene, 5 parts by mass of maleic anhydride, 0.1 parts by mass of t-butylperoxy-2-ethylhexanoate, 0.25 parts by mass of a-methyl styrene dimer, and 12 parts by mass of methyl ethyl ketone were charged. After replacing the gaseous phase of the system with nitrogen gas, the temperature was raised to 92° C. over 40 minutes with agitation. After raising the temperature, the temperature was kept at 92° C., and a solution prepared by dissolving 30 parts by mass of maleic anhydride and 0.22 parts by mass of t-butylperoxy-2-ethylhexanoate in 75 parts by mass of methyl ethyl ketone and 28 parts by mass of styrene were added continuously over 7 hours. Further, after completion of the addition of maleic anhydride, 17 parts by mass of styrene was added continuously over 2 hours. After adding styrene, the temperature of the reaction mixture was raised to 120° C., and the reaction was carried out for 1 hour to complete polymerization. Thereafter, 21.2 parts by mass of aniline and 0.3 parts by mass of triethylamine were added to the polymerization solution, and reaction was carried out at 140° C. for 7 hours. The imidizing reaction solution after completion of reaction was fed to a vent type screw extruder, and the volatile component was removed to obtain pellet maleimide-based copolymer A-1. The constituting unit was 51 mass % or styrene unit, 48 mass % of N-phenyl maleimide unit, and 1 mass % of maleic anhydride unit. The mid-point glass transition temperature (Tmg) measured by DSC was 186° C., and the weight average molecular weight was 90,000.

<Production Example of Maleimide-Based Copolymer (A-2)>

[0093] To an autoclave having a capacity of about 120 liters equipped with an agitator, 20 parts by mass of styrene, 5 parts by mass of maleic anhydride, 0.1 parts by mass of parts by mass of t-butylperoxy-2-ethylhexanoate, 0.13 parts by mass of a-methyl styrene dimer, and 12 parts by mass of methyl ethyl ketone were charged. After replacing the gaseous phase of the system with nitrogen gas, the temperature was raised to 92° C. over 40 minutes with agitation. After raising the temperature, the temperature was kept at 92° C., and a solution prepared by dissolving 35 parts by mass of maleic anhydride and 0.22 parts by mass of t-butylperoxy-2-ethylhexanoate in 75 parts by mass of methyl ethyl ketone and 28 parts by mass of styrene were added continuously over 7 hours. Further, after completion of the addition of maleic anhydride, 12 parts by mass of styrene was added continuously over 2 hours. After adding styrene, the temperature of the reaction mixture was raised to 120° C., and the reaction was carried out for 1 hour to complete polymerization. Thereafter, 23.1 parts by mass of aniline and 0.3 parts by mass of triethylamine were added to the polymerization solution, and reaction was carried out at 140° C. for 7 hours. The imidizing reaction solution after completion of reaction was fed to a vent type screw extruder, and the volatile component was removed to obtain pellet maleimide-based copolymer A-2. The constituting unit was 47 mass % or styrene unit, 52 mass % of N-phenyl maleimide unit, and 1 mass % of maleic anhydride unit. The mid-point glass transition temperature (Tmg) measured by DSC was 195° C., and the weight average molecular weight was 130,000.

<Production Example of Maleimide-Based Copolymer (A-3)>

[0094] To an autoclave having a capacity of about 120 liters equipped with an agitator, 20 parts by mass of styrene, 10 parts by mass of acrylonitrile, 5 parts by mass of maleic anhydride, 0.1 parts by mass of parts by mass of t-butylperoxy-2-ethylhexanoate, 0.10 parts by mass of α-methyl styrene dimer, and 12 parts by mass of methyl ethyl ketone were charged. After replacing the gaseous phase of the system with nitrogen gas, the temperature was raised to 92° C. over 40 minutes with agitation. After raising the temperature, the temperature was kept at 92° C., and a solution prepared by dissolving 34 parts by mass of maleic anhydride and 0.22 parts by mass of t-butylperoxy-2-ethylhexanoate in 75 parts by mass of methyl ethyl ketone and 28 parts by mass of styrene were added continuously over 7 hours. Further, after completion of the addition of maleic anhydride, 13 parts by mass of styrene was added continuously over 2 hours. After adding styrene, the temperature of the reaction mixture was raised to 120° C., and the reaction was carried out for 1 hour to complete polymerization. Thereafter, 20.7 parts by mass of aniline and 0.3 parts by mass of triethylamine were added to the polymerization solution, and reaction was carried out at 140° C. for 7 hours. The imidizing reaction solution after completion of reaction was fed to a vent type screw extruder, and the volatile component was removed to obtain pellet maleimide-based copolymer A-3. The constituting unit was 48 mass % or styrene unit, 46 mass % of N-phenyl maleimide unit, and 6 mass % of maleic anhydride unit. The mid-point glass transition temperature (Tmg) measured by DSC was 195° C., and the weight average molecular weight was 140,000.

<Production Example of ABS Resin (ABS-1)>

[0095] ABS resin was prepared by emulsion-graft polymerization method. To a reactor equipped with an agitator, 97 parts by mass of polybutadiene latex (solid concentration: 50 mass %, average particle diameter: 0.3 μm), 12 parts by mass of a styrene-butadiene latex having a styrene content of 24 mass % (solid concentration: 70 mass %, average particle diameter: 0.5 μm), 1 part by mass of sodium stearate, 0.2 part by mass of sodium formaldehyde sulfoxylate, 0.01 parts by mass of ethylenediaminetetraacetic acid tetrasodium, 0.005 parts by mass of ferrous sulfate, and 200 parts of pure water were added. The reaction mixture was heated to 50° C. Subsequently, 43 parts by mass of a monomer mixture containing 75 mass % of styrene and 25 mass % of acrylonitrile, 0.2 parts by mass of t-dodecyl mercaptan, and 0.06 parts by mass of t-butyl peroxyacetate were continuously added separately over 5 hours. After completion of the separate addition, 0.04 parts by mass of diisopropyl benzene peroxide was added and the reaction was carried out for 2 hours at 70° C. to complete polymerization, thereby obtaining a latex of ABS resin. To the obtained latex, 0.3 parts of Irganox 1076 (available from BASF Japan Ltd.) was added. Thereafter, the reaction solution was subjected to coagulation using magnesium sulfate and sulfuric acid so that the pH of the slurry during solidification was 6.8. The coagulated matter was washed and dehydrated, followed by drying to obtain powdered ABS resin. The content of the rubbery polymer was 57 mass % based on the formulation ratio of the raw materials. The constituting unit other than the rubbery polymer measured by NMR was 75 mass % of styrene unit and 25 mass % of acrylonitrile unit. From the observation by transmission electron microscope it became apparent that ABS resin was dispersed as particles, and its volume average particle diameter was 0.4 μm. Content of volatile components in the ABS resin was 6,000 μg/g for styrene and below detection limit (30 μg/g) for acrylonitrile.

<Production Example of SAN resin (SAN-1)>

[0096] SAN resin was prepared by continuous bulk polymerization. One continuous stirred tank mixing vessel was used as the reactor, and polymerization was performed with a capacity of 20 L. A raw material solution containing 60 mass % of styrene, 22 mass % of acrylonitrile, and 18 mass % of ethyl benzene was prepared, and was continuously supplied to the reactor at a flow rate of 6.5 L/h. Further, t-butyl peroxy isopropyl monocarbonate as the polymerization initiator and n-dodecyl mercaptan as the chain transfer agent were continuously added to the supply line of the raw material solution so that the concentration would be 160 ppm and 400 ppm, respectively. The reaction temperature of the reactor was adjusted to 145° C. The polymer solution taken continuously from the reactor was supplied to the vacuum devolatilization tank equipped with a pre-heater, and unreacted styrene and acrylonitrile, and ethyl benzene were removed. Temperature of the pre-heater was adjusted so that the temperature of the polymer in the devolatilization tank would be 225° C., and the pressure in the devolatilization tank was set to 0.4 kPa. Polymer was taken out from the vacuum devolatilization tank using a gear pump and was extruded into strands. The strands were cooled in cooling water and were cut to obtain pelletized SAN resin. The constituting unit of the SAN resin was 74 mass % of styrene unit and 26 mass % or acrylonitrile. The weight average molecular weight of the SAN resin was 100,000.

<Production Example of SAN resin (SAN-2)>

[0097] SAN resin was prepared by continuous bulk polymerization. One continuous stirred tank mixing vessel was used as the reactor, and polymerization was performed with a capacity of 20 L. A raw material solution containing 57 mass % of styrene, 25 mass % of acrylonitrile, and 18 mass % of ethyl benzene was prepared, and was continuously supplied to the reactor at a flow rate of 6.5 L/h. Further, t-butyl peroxy isopropyl monocarbonate as the polymerization initiator and n-dodecyl mercaptan as the chain transfer agent were continuously added to the supply line of the raw material solution so that the concentration would be 160 ppm and 400 ppm, respectively. The reaction temperature of the reactor was adjusted to 145° C. The polymer solution taken continuously from the reactor was supplied to the vacuum devolatilization tank equipped with a pre-heater, and unreacted styrene and acrylonitrile, and ethyl benzene were removed. Temperature of the pre-heater was adjusted so that the temperature of the polymer in the devolatilization tank would be 225° C., and the pressure in the devolatilization tank was set to 0.4 kPa. Polymer was taken out from the vacuum devolatilization tank using a gear pump and was extruded into strands. The strands were cooled in cooling water and were cut to obtain pelletized SAN resin. The constituting unit of the SAN resin was 70 mass % of styrene unit and 30 mass % or acrylonitrile. The weight average molecular weight of the SAN resin was 120,000.

<Production Example of SAN resin (SAN-3)>

[0098] SAN resin was prepared by continuous bulk polymerization. One continuous stirred tank mixing vessel was used as the reactor, and polymerization was performed with a capacity of 20 L. A raw material solution containing 60 mass % of styrene, 22 mass % of acrylonitrile, and 18 mass % of ethyl benzene was prepared, and was continuously supplied to the reactor at a flow rate of 6.5 L/h. Further, t-butyl peroxy isopropyl monocarbonate as the polymerization initiator was continuously added to the supply line of the raw material solution so that the concentration would be 160 ppm. The reaction temperature of the reactor was adjusted to 145° C. The polymer solution taken continuously from the reactor was supplied to the vacuum devolatilization tank equipped with a pre-heater, and unreacted styrene and acrylonitrile, and ethyl benzene were removed. Temperature of the pre-heater was adjusted so that the temperature of the polymer in the devolatilization tank would be 225° C., and the pressure in the devolatilization tank was set to 0.4 kPa. Polymer was taken out from the vacuum devolatilization tank using a gear pump and was extruded into strands. The strands were cooled in cooling water and were cut to obtain pelletized SAN resin. The constituting unit of the SAN resin was 70 mass % of styrene unit and 30 mass % or acrylonitrile. The weight average molecular weight of the SAN resin was 145,000.

<Additive-1>

[0099] HP 4051 available from DOW-MITSUI POLYCHEMICALS CO., LTD. was used as additive-1.

<Additive-2>

[0100] L-1000 available from Mitsubishi Chemical Corporation was used as additive-2.

<Additive-3>

[0101] SH-200 10CS available from HANWA SANGYO Co., Ltd was used as additive-3.

<Additive-4>

[0102] PEG-20000 available from Sanyo Chemical Industries, Ltd. was used as additive-4.

<Examples, Comparative Examples>

[0103] Maleimide-based copolymer, ABS resin, and SAN resin in the formulation shown in Table 1 were subjected to melt-kneading and devolatilization-extruding using an extruder to obtain heat resistant resin composition. Twin-screw extruder (TEM-35B, available from TOSHIBA MACHINE CO., LTD, currently SHIBAURA MACHINE CO., LTD.) was used as the extruder. Regarding the constitution of the extruder, a kneading unit in which melt-kneading of each of the resins was performed was provided, followed by another kneading unit in which water was added and kneaded, and then a devolatilization unit was provided. The temperature of the cylinders of the kneading unit and the devolatilization unit were set to the temperature shown in Table 1. Extrusion was performed with a screw rotation speed of 250 rpm and a feed rate of 30 kg/hr. Water was added so that the addition amount with respect to the fed amount would be 0.5 mass %. The pressure of the devolatilization unit was 10 mmHg. The following evaluations were conducted for the heat resistant resin composition thus obtained. Evaluation results are shown in Tables 1 and 2.

[0104] (G′/G″)

[0105] Measurement of G′/G″ was performed by using viscoelasticity measuring apparatus DHR available from TA Instruments Japan Inc. Parallel plate of 25 mm was used for the measurement, with a gap of 0.75 mm, strain of 5% and measurement temperature of 240° C. The value of G′/G″ at an angular velocity of 0.63 rad/s are shown in Tables 1 and 2.

(Vicat Softening Temperature)

[0106] Vicat softening temperature was measured in accordance with JIS K-7206. Here, Method 50 (load: 50N, temperature elevation rate: 50° C./hour) was used, and the test specimen having the size of 10 mm×10 mm and 4 mm thickness was used. HDT & VSPT testing device available from Toyo Seiki Seisaku-sho, Ltd. was used as the measuring instrument.

(Melt Mass Flow Rate)

[0107] Melt mass flow rage was measured in accordance with JIS K-7210, at 220° C. with 10 kg load.

(Charpy Impact Strength)

[0108] Charpy impact strength was measured using a notched specimen in accordance with JIS K-7111-1. Edgewise was adopted as the striking direction. Here, digital impact tester available from Toyo Seiki Seisaku-sho, Ltd. was used as the measuring instrument.

(Stringing Property)

[0109] In accordance with JIS K-7171, stringing property was observed by using a test specimen having a size of 80 mm×10 mm×4 mm. The test specimen was pressed onto a heated plate of 240° C. with 1 kg load for 10 seconds and then the test specimen was drawn up at a rate of 10 cm/sec. The stringing property was evaluated by a scale of 5 with the following criteria using the length of stringed resin.

[0110] A: stringing was cut by a length of less than 1.0 cm; B: stringing was cut by a length of 1.0 cm or more to less than 4.0 cm. C: stringing was cut by a length of 4.0 cm or more to less than 7.0 cm; D: stringing was cut by a length of 7.0 cm or more to less than 10.0 cm; E: stringing was elongated to 10 cm or longer.

(Chemical Resistance)

[0111] Cracks of a test specimen having a shape of 316×20×2 mm were observed after 48 hours at 23° C. by a quarter ellipse method having a major radius of 250 mm and a minor radius of 150 mm. In order to eliminate influence of molding strain, the test specimen was produced by pressing and cutting out a pellet at 260° C. Toluene was used as the chemical.

[0112] Critical strain was obtained by the following equation.

ϵ=b/2a.sup.2 [1−(a.sup.2−b.sup.2)X.sup.2/a.sup.4].sup.1.5×t×100

[0113] Critical strain: ϵ, major radius: a, minor radius: b, thickness of test specimen: t, crack initiation point: X

[0114] The chemical resistance was evaluated from the critical strain according to the following criteria.

[0115] A: 0.8 or more, B: 0.6 to 0.7, C: 0.3 to 0.5, D: 0.2 or less

[Table 1]

[0116]

TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 7 8 9 10 11 12 13 result formu- resin (B) ABS-1 mass % 20 20 20 20 20 20 20 20 20 20 20 20 20 of lation SAN-1 mass % 50 60 60 60 60 60 60 physical amount SAN-2 mass % 60 50 60 property SAN-3 mass % 60 10 10 70 50 eval- copolymer A-1 mass % 20 20 30 30 10 10 10 10 10 10 30 uation (A) A-2 mass % 20 A-3 mass % 20 10 10 10 formulation (A) + (B) parts by 100 100 100 of additive mass additive-1 parts by 1 2 mass additive-2 parts by 2 mass G′/G″ — 0.38 0.46 0.32 0.40 0.32 0.35 0.32 0.32 0.75 0.90 0.56 0.51 0.52 Vicat softening 50N ° C. 113 116 118 120 106 107 112 112 111 111 111 110 122 temperature MFR 220° C., g/10 min 8 5 11 7 25 14 12 9 18 18 17 3 3 10 kg Charpy impact with notch kJ/m.sup.2 5.1 11.9 5.1 4.6 6.6 5.6 6.3 4.2 6.2 6.2 6 15.3 9.4 strength stringing property B A C A C C C C A A A A A chemical resistance B B B B A B B B A A A D D

TABLE-US-00002 TABLE 2 Comparative Example 1 2 3 4 5 6 7 8 result formulation resin (B) ABS-1 mass % 20 20 20 20 20 20 25 12.5 of amount SAN-1 mass % 60 70 60 60 60 75 37.5 physical SAN-2 mass % 70 property SAN-3 mass % evaluation copolymer (A) A-1 mass % 20 10 20 10 20 20 0 50 formulation of (A) + (B) parts by mass 100 100 100 additive additive-1 parts by mass 2 additive-3 parts by mass 2 additive-4 parts by mass 2 G′/G″ — 0.15 0.12 0.29 0.16 0.16 0.15 0.10 1.10 Vicat softening temperature 50N ° C. 111 104 103 106 111 111 100 130 MFR 220° C., 10 kg g/10 min 18 29 30 17 20 18 24 3 Charpy impact strength with notch kJ/m.sup.2 5.8 6.6 6.9 5.6 6.5 6.1 9.0 1.0 stringing property E E D E E E E A chemical resistance A A A A A A A E

[0117] From the results of Tables 1 and 2, when G′/G″ of the resin had a value of 0.30 to 1.00, the stringing property was improved, and thus heat resistant resin composition having heat resistance and appearance with superior balance was obtained. In Examples 1 to 11, chemical resistance was high, and in Examples 5, and 9 to 11, chemical resistance was especially superior. In addition, when the MFR of the resin was 5 or higher, the chemical resistance of the resin was improved even higher. Further, when additive was used, G′/G″ was increased, thereby resulting in improvement in stringing property.

[0118] The mechanism on how the stringing property can be improved by controlling the G′/G″ still remains unsolved. Here, one assumption is that the indicator related to the dynamic viscoelasticity of the resin composition when the resin composition is in a molten state during fusion-bonding using heated plates has an influence on the stringing property. With the present invention, it became apparent that when G′/G″ among various indicators related to the dynamic viscoelasticity was controlled within a certain range, it can contribute greatly in improving the stringing property.

INDUSTRIAL APPLICABILITY

[0119] By using the heat resistant resin composition of the present invention, molding can be carried out without appearance defects even when adhesion is performed by fusion-bonding using heated plates, which is a low-cost bonding technology. In addition, even when a resin with high flowability is used to improve productivity, molding can be carried out without appearance defects. In addition, by controlling the value of G′/G″ of the resin in the afore-mentioned range, heat resistant resin composition having flowability, chemical resistance, heat resistance and appearance with superior balance can be obtained. The heat resistant resin composition can be suitably used in applications such as automobiles, home appliances, office automation equipment, housing materials, and daily necessities.