JPH0336060B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new polycarbonate resin composition with improved paintability, and more specifically, a polycarbonate resin composition that has a high degree of chemical resistance, excellent paintability, and good impact resistance and processability, and a rubber-modified heat-resistant polycarbonate resin composition. The invention relates to compositions with plastic polymers. Polycarbonate resin is an engineering plastic with high heat resistance and is widely used in various fields. As a method to improve the processability and chemical resistance of polycarbonate resin, as well as to give it a higher degree of impact resistance, ABS resin and MBS resin, which are a type of rubber-modified thermoplastic resin, have traditionally been used.
It has been proposed to use a blend of resins and the like. In addition, in recent years, as exterior materials for automobiles and light electrical equipment that require heat resistance, materials that have undergone secondary processing through painting to improve aesthetics and weather resistance have been desired, and polycarbonate resin and rubber-modified thermoplastic resin Although progress has been made to use compositions consisting of these for such purposes, various problems have arisen. In general, rubber-modified thermoplastic resins such as ABS resin and MBS resin have good adhesion with paints and affinity with thinners, so they have excellent paintability. Painting things. However, with compositions of polycarbonate resin and rubber-modified thermoplastic resin, poor paintability has become a problem, and due to the poor chemical resistance of polycarbonate resin, stress cracking is caused by thinners during painting. Conventional compositions do not have sufficient paintability due to problems such as lifting of the paint film (paint peeling) when solvents such as gasoline adhere to painted surfaces in the automotive field. It's not something I'm satisfied with. Therefore, the present inventors conducted extensive studies to take advantage of the excellent properties of the composition of polycarbonate resin and rubber-modified thermoplastic resin and to improve the paintability, and finally arrived at the present invention. An object of the present invention is to provide a thermoplastic resin composition that has a high degree of chemical resistance, excellent paintability, and good impact resistance and processability. That is, the thermoplastic resin composition of the present invention contains 20 to 90 parts by weight of the polycarbonate resin (A) and 90 to 40 parts by weight of the monomer in the presence of 10 to 60 parts by weight of the (a) rubbery polymer.
Parts by weight (however, the total of rubbery polymer and monomer is
100 parts by weight) is first composed of 0-20% by weight of unsaturated nitrile monomer and 100-80% by weight of aromatic vinyl monomer, and 30-70% by weight of the total monomer mixture. (b) then 35 to 90 weight % of unsaturated nitrile monomers and 65 to 90 weight % of aromatic vinyl monomers;
The remaining monomer mixture consisting of 10% by weight is polymerized, and the content of unsaturated nitrile monomer in the monomer polymerized portion produced by the polymerization of (a) and (b) above is 28 to 38% by weight. % thermoplastic resin (B) in an amount of 80 to 10% by weight. The polycarbonate resin used in the present invention includes commonly used aromatic polycarbonates, aliphatic polycarbonates, modified polycarbonates, and the like. Examples of modified polycarbonates include halogenated polycarbonates that have been halogenated with chlorine, bromine, or the like. Among these polycarbonate resins, aromatic polycarbonates are preferred, and aromatic polycarbonates produced by the phosgene method or ester conversion method using bisphenol as the main raw material, especially 2,2-(4,4'- A typical example is 4,4'-dihydroxydiphenyl-based alkane-based polycarbonate obtained using hydroxydiphenyl-propane, so-called bisphenol A. As these polycarbonate resins, commercially available polycarbonate resins can be used as long as the type, physical properties, etc. are clear from catalog values. The rubbery polymer used in the present invention includes polybutadiene, acrylonitrile-butadiene copolymer,
Examples include styrene-butadiene copolymer, isoprene rubber, chloroprene rubber, acrylic rubber, and ethylene-propylene-diene rubber.
Manufactured by bulk polymerization method etc. The monomers used in the production of the rubber-reinforced thermoplastic resin (B) of the present invention are unsaturated nitrile monomers and aromatic vinyl monomers, and examples of the unsaturated nitrile monomers include acrylonitrile and methane. Examples include acrylonitrile. In addition, examples of aromatic vinyl monomers include styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene,
Examples include m-methylstyrene, chlorostyrene, bromustyrene, and vinylnaphthalene. These monomers can be used alone or in combination of two or more. In addition, if necessary, other copolymerizable monomers, such as unsaturated acid esters such as methyl methacrylate, may be substituted for a part of the aromatic vinyl monomer to the extent that the object of the present invention is not affected. It can be used. The thermoplastic resin (B) of the present invention can be produced, for example, by conventional emulsion polymerization, solution polymerization, or bulk polymerization. That is, a monomer mixture consisting of an unsaturated nitrile monomer and an aromatic vinyl monomer is graft-polymerized in the presence of the rubbery polymer. In the present invention, a monomer mixture consisting of an unsaturated nitrile monomer and an aromatic vinyl monomer in the presence of 10 to 60 parts by weight of a rubbery polymer, preferably 20 to 60 parts by weight, is used.
It is appropriate to graft-polymerize 90 to 40 parts by weight, preferably 80 to 40 parts by weight (the total of the rubbery polymer and monomer mixture is 100 parts by weight). If the amount of the rubbery polymer is less than 10 parts by weight, the thermoplastic resin of the present invention has a disadvantage in that the impact resistance is reduced. On the other hand, 60
If it exceeds parts by weight, the amount of graft bonding of the resin component to the rubbery polymer will be small, and the thermal stability of the rubber-reinforced thermoplastic resin will be reduced, which is not preferable. When blending with polycarbonate resin (A), it is difficult to knead uniformly. The composition of the monomer mixture of the rubber-reinforced thermoplastic resin in the present invention is such that the unsaturated nitrile monomer is 28 to
38% by weight and 72-62% by weight of aromatic vinyl monomers
The former is preferably 30 to 38% by weight, and the latter is preferably 70 to 38% by weight.
It is 62% by weight. In order to improve the impact resistance, paint resistance and solvent resistance of the mixed composition with the polycarbonate resin, it is preferable that the unsaturated nitrile monomer content be 28% by weight or more. On the other hand, if it exceeds 38% by weight, disadvantages such as decreased processability and impact resistance and increased tendency to heat coloring during high-temperature molding become noticeable. The mixing ratio of the polycarbonate resin (A) and the rubber-reinforced thermoplastic resin (B) is 20 to 90/80 to 10% by weight, and if the polycarbonate resin is less than 20% by weight, the impact resistance and heat resistance will be low, which is undesirable. If it exceeds % by weight, it will not be possible to obtain a product with improved paintability. In order to make the present invention more effective, that is, in order to provide special and excellent paintability and chemical resistance, in the production of rubber-reinforced thermoplastic resins, unsaturated nitrile monomers are used in the presence of rubbery polymers. and an aromatic vinyl monomer, first, in the first step (a), the content of unsaturated nitrile monomer is 0 to 20% by weight, more preferably 0 to 18% by weight. % and of the total monomer mixture
After polymerizing the monomer mixture in an amount corresponding to 30 to 70% by weight, preferably 30 to 60% by weight, the content of unsaturated nitrile monomers is then reduced to 35% in the second and subsequent polymerization stages (b). ~90% by weight preferably 40-70% by weight
It is important to polymerize the remaining monomer mixture. If the content of unsaturated nitrile monomers in the monomer mixture used in the first stage exceeds 20% by weight, chemical resistance will decrease. Furthermore, if the amount of the monomer mixture used at this stage is less than 30% by weight of the total monomer mixture, the improvement in paintability and chemical resistance will not be significant.
On the other hand, if it exceeds 70% by weight, processability deteriorates and the effect of improving paintability becomes small, which is not preferable. Next, in the second and subsequent stages, the remaining monomer mixture is polymerized, but if the content of unsaturated nitrile monomer in the monomer mixture is less than 35% by weight, the paintability and chemical resistance will decrease. If the amount is too large, the polymerization conversion rate will decrease, which is not preferable. In both the first and second stages of the graft reaction, the polymerization may be carried out by adding monomers, initiators, etc. all at once, in portions, or continuously, by a conventional polymerization method. Furthermore, if the unsaturated nitrile content in the monomer composition is 28 to 38% by weight, there is no particular restriction on the distribution of the monomers in the case of divided addition. The content of unsaturated nitrile monomer in the monomer polymerization portion of the rubber-reinforced thermoplastic resin thus obtained is
If it is 28 to 38% by weight, the physical property balance of chemical resistance, impact resistance, and processability will be good in the mixed composition with polycarbonate resin. Furthermore, a copolymer of at least one aromatic vinyl monomer, at least one unsaturated nitrile monomer, and optionally at least one unsaturated acid ester monomer such as methyl methacrylate, such as a commercially available It is also possible to blend AS resin etc. into the composition of the present invention, but the mixing ratio of the above copolymer and rubber-reinforced thermoplastic resin (B) is preferably 0 to 0.
70/100 to 30% by weight, more preferably 0 to 60/100
~40% by weight. If (B) is less than 30%, the desired effect of the present invention will be reduced. In these cases, a rubber-reinforced thermoplastic resin with a high content of the rubbery polymer of the present invention is prepared in advance,
Good results can be obtained by controlling the rubbery polymer content in the resin composition finally obtained by blending this with AS resin and polycarbonate resin to 5 to 40% by weight. In addition, in order to improve the chemical resistance, processability, and impact resistance of the final resin composition, the AS resin used must have a high content of unsaturated nitrile monomer of 30% or more, and methyl ethyl ketone at 30°C. It is desirable that the intrinsic viscosity of the inside is 0.35 dl/g or more. The thermoplastic resin composition obtained in this way improves chemical resistance and paintability, which are disadvantages of polycarbonate resin, and has good impact resistance, heat resistance, and processability, so it is used industrially in the field of coating materials. The utility value is extremely large. The present invention will be explained in more detail with reference to the following examples, but the scope of the present invention is not limited by these examples unless the scope of the present invention is exceeded. In each of the following examples, parts and % represent parts by weight and % by weight. Method for producing rubber-reinforced thermoplastic resin (method for producing rubbery polymer latex) Using a fatty acid soap as an emulsifier, using a redox initiator consisting essentially of cumene hydroperoxide and ferrous sulfate as an initiator, A polybutadiene latex with enlarged latex particles was prepared by emulsion polymerizing butadiene using -dodecyl mercaptan as a chain transfer agent and forcibly stirring during the polymerization. The polymerization time was 60 hours, and the conversion rate was 60%. The resulting latex A had an average gel content of 78%,
The weight fraction of particles larger than 3100 Å measured by the sodium alginate method was 60%. Production of rubber-reinforced thermoplastic resin (hereinafter referred to as graft polymer) Reaction vessel equipped with a stirring device, heating jacket, reflux condenser, thermometer, nitrogen gas inlet, and continuous addition device for monomer emulsion and polymerization initiator. The following reagents were charged into the flask, the atmosphere was replaced with nitrogen, the temperature was raised, and graft polymerization was carried out at 70°C for 1 hour. Rubbery polymer latex (as solid content) 16 parts Polybutadiene latex (as solid content) (JSR0700 manufactured by Japan Synthetic Rubber Co., Ltd.) 24 parts styrene 18 parts acrylonitrile 2 parts disproportionated potassium rosin acid 1.0 parts terpinolene 0.02 parts cumene Hydroperoxide 0.10 parts Dextrose 0.35 parts Sodium pyrophosphate 0.30 parts Ferrous sulfate 0.01 parts Ion-exchanged water 150 parts Further, the following mixture was continuously added over 2 hours. Styrene: 22 parts Acrylonitrile: 18 parts Cumene hydroperoxide: 0.20 parts Terpinolene: 0.20 parts After addition, the reaction was continued with stirring for an additional hour. After adding 1.0 part of 2,6-di-t-butyl para-cresol as an anti-aging agent to the obtained graft polymer latex, sulfuric acid (2 parts per 100 parts of polymer) was added and coagulated. Disassemble it, wash it with water,
The graft polymer (2) obtained by dehydration and drying had an acrylonitrile content of 31% (according to Coleman analysis, hereinafter the same) in the monomer polymerized portion. Table 1 shows the graft polymers obtained above ()
and AS resin (acrylonitrile content 32%,
Intrinsic viscosity in methyl ethyl ketone at 30℃ 0.45 dl/
g) and a polycarbonate resin (Polycarbonate FN2200 manufactured by Idemitsu Petrochemical Co., Ltd.) were mixed at different composition ratios and pelletized at 250°C using an extruder. The results of measuring the physical properties of the compositions are shown below. As a result, the thermoplastic resin composition of the present invention
A resin composition with a better balance of impact resistance, fluidity, heat resistance, and paintability than the ABS resin and polycarbonate resin shown in Comparative Example 1 can be obtained. The fluidity during processing was measured at 230°C using a Koka type flow tester (nozzle 1φ x 2mm, load 30Kg/cm). Izotsu impact strength was determined by molding specified test pieces at 250℃ using a 5-ounce injection molding machine.
Measured at 23°C according to the method of ASTMD256. The paintability test was carried out using a 1 oz injection molding machine.
A test piece of 55 mm x 80 mm x 1.6 mm was molded at 250°C and tested in the following manner. A test piece was spray-coated with urethane paint (Planet PA Origin Electric Co., Ltd.), left to stand for a certain period of time (3 hours) after drying, and then immersed in gasoline to measure the time until the urethane paint film swelled and peeled off. It is determined that the longer this time is, the better the coating performance is.

【table】

[Table] Example 2, Comparative Example 2 Polymerization and blending were carried out in the same manner as in Example 1, except that styrene and acrylonitrile during graft polymerization were varied as shown in Table 2. Table 2 shows the composition of the graft polymer and the physical properties of the obtained resin. Comparative Example 3 Polymerization and blending were carried out in the same manner as in Example 1, except that styrene and acrylonitrile during graft polymerization were varied as shown in Table 2. Table 2 also shows the composition of the graft polymer and the physical properties of the resin, which is a mixture composition of the graft polymer, AS resin, and polycarbonate resin. From the results shown in Table 2, Comparative Example 3 (1) has a low acrylonitrile content in the graft polymer composition, so the coating performance of the final composition is poor. On the other hand, in case (2), the acrylonitrile content is too high, so the fluidity of the final composition is poor and it is difficult to obtain a coated product with a good surface condition.

【table】

[Table] Example 2 (2) has the same composition as Example 1 (3) Example 3, Comparative Example 4 The following reagents were charged into the reaction apparatus described in Example 1, and the temperature was raised after purging with nitrogen. Graft polymerization was carried out at 70°C for 1 hour. Rubber polymer (as solid content) (same as Example 1)
9.6 parts polybutadiene latex (as solid content) (JSR0700 manufactured by Japan Synthetic Rubber Co., Ltd.) 14.4 parts styrene 22 parts acrylonitrile 4 parts disproportionated potassium rosin acid 1.5 parts t-dodecyl mercaptan 0.03 parts cumene hydroperoxide 0.10 parts dextrose 0.35 parts Sodium pyrophosphate 0.30 parts Ferrous sulfate 0.01 parts Ion-exchanged water 150 parts Furthermore, the following mixture was continuously added over 2 hours. Styrene 28 parts Acrylonitrile 22 parts Cumene hydroperoxide 0.18 part t-Dodecyl mercaptan 0.25 parts After the addition, the reaction was continued for an additional hour with stirring. After adding 1.0 part of 2,6-di-t-butyl para-cresol as an anti-aging agent to the obtained graft polymer latex, a graft polymer was obtained by the method described in Example 1. The acrylonitrile content of this monomer polymerization part was 31%. Next, 50 parts by weight of the obtained graft polymer and 50 parts by weight of polycarbonate resin were mixed to form Example 1.
Pelletization and test pieces were prepared in the same manner as above, and the measurement results are shown in Table 3. The same results obtained by changing the monomer composition ratio during graft polymerization in the above Examples are shown in Table 3 as Examples and Comparative Examples. The acrylonitrile content in the styrene-acrylonitrile composition in the graft polymer is
Products within the scope of the present invention have excellent coating appearance, and in particular, those shown in this example in which the acrylonitrile content is 0 to 20% by weight at the initial stage of polymerization in the production method during graft polymerization, the coating film It is clear that the material has excellent swelling and peeling properties. Comparative Example 5 In the polymerization recipe of Example 3, the polymerization components other than styrene, acrylonitrile, and cumene hydroperoxide were charged into a reactor, and the reactor was purged with nitrogen and the temperature was raised to 70°C to remove the entire amount of styrene, acrylonitrile, and cumene hydroperoxide. Addition was continued over a period of 3 hours. The polymer was recovered and evaluated in the same manner as in Example 3, and the results are shown in Table 3.

【table】

Claims (1)

[Scope of Claims] 1 Monomers in the presence of 20 to 90% by weight of polycarbonate resin (A) and 10 to 60 parts by weight of (a) rubbery polymer.
In graft polymerizing 90 to 40 parts by weight (however, the total of the rubbery polymer and monomer is 100 parts by weight), first 0 to 40 parts by weight of unsaturated nitrile monomer are
20% by weight and 100-80% by weight of aromatic vinyl monomer
(b) Then, 35 to 90 weight % of unsaturated nitrile monomer and aromatic vinyl monomer are polymerized. Polymerize the remaining monomer mixture consisting of 65 to 10% by weight, and reduce the content of unsaturated nitrile monomers in the polymerized monomer portion produced by the polymerization of (a) and (b) above to 28% by weight. 1. A thermoplastic resin composition comprising 80 to 10% by weight of thermoplastic resin (B) in an amount of 38% by weight.