JPH03124764A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To prepare the title resin compsn. free from pearllike gloss and having excellent heat resistance, impact strength, and surface hardness by compounding a specified amt. of an acrylic core-shell polymer into a resin compsn. comprising an arom. polycarbonate resin and a polymethyl methacrylate resin. CONSTITUTION:The title thermoplastic resin compsn. is prepd. by compounding: 100 pts.wt. resin compsn. comprising 20-70wt.% arom. polycarbonate resin and 80-30wt.% polymethyl methacrylate resin; with 1-10 pts.wt. acrylic core-shell polymer. The core-shell polymer is pref. made up of a core comprising a rubberlike polymer and a shell comprising a glassy polymer modified with polar functional groups (e.g. carboxyl or hydroxyl group), and pref. has a mean particle diameter of 0.2-0.5mum.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a thermoplastic resin composition with improved surface hardness and excellent moldability, appearance, impact resistance, etc. The objective is to provide molding materials suitable for the field of manufacturing, miscellaneous goods, etc.

[Conventional technology and its problems]

Aromatic polycarbonate resins have excellent impact resistance, electrical properties, and good dimensional stability, and are therefore widely used as useful engineering plastics.

However, it had drawbacks such as relatively low surface hardness (and easy scratching).

On the other hand, polymethyl methacrylate resin has a high surface hardness for a plastic, but its heat resistance is slightly inferior and its impact resistance is also insufficient.

There is a composition of aromatic polycarbonate resin and polymethyl methacrylate resin (Japanese Patent Publication No. 43-13384), but this composition has pearlescent luster and is an inappropriate material for fields other than those that take advantage of this luster. The impact resistance was also insufficient. Therefore, as a method of improving this composition, a method of adding a butadiene-based elastomer (Japanese Patent Publication No.
7864), the method of adding MBS resin (Special Publication No. 1983),
-41507), but although the impact resistance was improved, it exhibited a pearlescent luster and the field of application was limited.

[Means to solve the problem]

As a result of intensive studies on improving the abrasion resistance of aromatic polycarbonate resin, the present inventors found that by blending an acrylic core-shell polymer into a composition of aromatic polycarbonate resin and polymethyl methacrylate resin, It was discovered that a composition that does not exhibit pearlescent luster could be obtained, and the present invention was completed based on this finding.

That is, the present invention provides a resin composition 1 consisting of (A) 20 to 70 parts by weight of an aromatic polycarbonate resin and (B) 80 to 30 parts by weight of a polymethyl methacrylate resin.
00 parts by weight, (C) and 1 to 10 parts by weight of an acrylic core-shell polymer. The polar functional group is a carboxyl group or a hydroxyl group, and the average particle diameter of the acrylic core-shell polymer (C) is 0.2 to 0.5p.
It is a thermoplastic resin composition consisting of a range of .

The present invention will be explained in detail below.

The aromatic polycarbonate resin (A) of the present invention is an optionally branched aromatic homo- or copolycarbonate made by reacting aromatic dihydroxy or a small amount of a polyhydroxy compound with phosgene or a diester of carbonic acid. and the viscosity average molecular weight is 19.000
~30,000 thermoplastic polycarbonate polymer.

An example of an aromatic dihydroxy compound is 2,2-bis(4
-hydroxyphenyl)propane (=bisphenol A
), Tetramethylbisphenol A1 Tetraethylbisphenol A1 Tetrabromobisphenol A1 Bis(
4-hydroxyphenyl)methane, 1,1-bis(4-
Hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 1゜1-bis(4-hydroxyphenyl)cyclohexane, 1-phenyl-1,1-
These include bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)-P-diisopropylbenzene, hydroquinone, and resorcinol-4,4-dihydroxydiphenyl, which may be used either singly or as a mixture of two or more. In addition, in order to obtain a branched aromatic polycarbonate resin, phloroglucin, 4,6-dimethyl-2゜4.6-)li(4-hydroxyphenyl)hebutene-2,4,6-dimethyl-2.4.6- ) ri
(4-hydroxyphenyl)hebutane, 2,6-dimethyl-2.4.6-)li (4-hydroxyphenyl)
Hebutene-3,4,6-dimethyl-2,4.6-)li(4-hydroxyphenyl)heptane, 1,3.5-
tri(4-hydroxyphenyl)benzene, 1, 1.
Polyhydroxy compounds such as 1-tri(4-hydroxyphenyl)ethane and 3,3-bis(4-hydroxyphenyl)ethane,
-Hydroxyaryl)oxindole (=isatin bisphenol), 5-chloroisatin, 5.7-dichloroisatin, 5-bromiisatin, etc., are added to a part of the dihydroxy compound, for example 0.02 to 1.0 mol%, with a polyhydroxy compound. Replace. Furthermore, monovalent aromatic hydroxy compounds suitable for controlling the molecular weight are m- and p-methylphenol, m- and p-propylphenol, p-bromophenol, p-tert-butylphenol and p-& chain alkyl-substituted phenol. Examples include phenol, which is used in an amount of 1 to 10 mol%, preferably 2.0 to 3.5 mol% of the dihydroxy compound. A typical aromatic polycarbonate resin is bis(
Examples include polycarbonate based on 4-hydroxyphenyl)alkane dihydroxy compounds, especially bisphenol A as the main raw material, polycarbonate copolymers obtained by using two or more aromatic dihydroxy compounds together, and small amounts of trivalent phenol compounds. Branched polycarbonate obtained in combination can also be mentioned. Aromatic polycarbonate resins may be used as a mixture of two or more types.

Component (B) of the present invention is polymethyl methacrylate resin, which is a thermoplastic resin mainly composed of methyl methacrylate, but also includes ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl acrylate, It may contain an alkyl ester of methacrylic acid, exemplified by butyl acrylate, amyl acrylate, hexyl acrylate, and the like.

The acrylic core-shell polymer of component (C) of the present invention is a multilayer polymer consisting of a core made of a rubbery polymer and a shell made of a glassy polymer covering the core, and the shell preferably has a polar functional group. used. This core-shell polymer can be obtained by a sequential multi-stage seeded emulsion polymerization process in which the polymer of an earlier stage is coated with the polymer of a later stage, and in the present invention at least two stages of emulsion polymerization are performed. will be held.

In the first stage polymerization, an alkyl acrylate monomer having an alkyl group having 2 to 8 carbon atoms is polymerized to form a rubbery polymer preferably having a glass transition temperature of -20°C or lower. Examples of alkyl acrylates in which the alkyl group has 2 to 8 carbon atoms include ethyl acrylate, propyl acrylate, butyl acrylate, cyclohexyl acrylate, 2-
Examples include ethylhexyl acrylate. Also,
For polymerization, monomers copolymerizable with alkyl acrylate, such as aromatic vinyl such as styrene, vinyltoluene, and α-methylstyrene, vinyl cyanide such as aromatic vinylidene, acrylonitrile, and methacrylate trile, vinylidene cyanide, and methyl methacrylate are used. , alkyl methacrylate such as butyl methacrylate, etc. can also be copolymerized. Furthermore, small amounts of crosslinking monomers and grafting monomers can be polymerized as needed. Examples of crosslinkable monomers include aromatic divinino L/ such as divinylbenzene and divinyltoluene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, butylene glycol diacrylate,
Examples include hexanediol diacrylate, hexanediol dimethacrylate, oligoethylene glycol diacrylate, oligoethylene glycol dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, and alkane polyol polyacrylate. Examples of the grafting monomer include unsaturated carboxylic acid allyl esters such as allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, diallyl itaconate, and the like.

The second stage (or final stage) of polymerization for forming the shell involves polymerizing at least one monomer selected from the group consisting of alkyl acrylates and methacrylates having 1 to 4 carbon atoms, preferably glass rearrangement. A glassy polymer is formed at a temperature of 40°C or higher. If a monomer having a polar functional group is copolymerized at this time, the effect of eliminating pearlescent luster will be improved. Examples of the alkyl (meth)acrylate having 1 to 4 carbon atoms include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, and butyl methacrylate. Monomers with polar functional groups include acrylic acid, methacrylic acid, itaconic acid, fumaric acid,
Carboxyl group-containing monomers such as maleic acid, 2-
Examples include monomers having a hydroxyl group such as hydroxyethyl methacrylate and 2-hydroxyethyl acrylate. The monomer having a polar functional group is used in an amount of 0.1 to 10% by weight, preferably 0.5 to 2% by weight, based on the entire core-shell polymer. Furthermore, it is also possible to copolymerize crosslinkable monomers that can be used in the first stage polymerization, such as monomers that can be copolymerized with alkyl (meth)acrylates, such as aromatic monomers such as styrene, vinyltoluene, and α-methylstyrene. group vinylidene aromatic vinylidene,
Vinyl cyanide such as acrylonitrinopemethacrylonitrile, vinylidene cyanide, etc. can be copolymerized.

The above explanation has focused on the case of two-stage polymerization, but between the polymerization of the core in the first stage and the polymerization of the shell forming the outer layer, which is the final stage, a monomer or a plurality of monomers having different monomer compositions are used. Polymerization can be carried out to form a layer of.

The core-shell polymer can be extracted in the form of granules, flakes, or powder by separating the solid content from latex produced by a known seed emulsion polymerization method by a method such as salting out or freeze-abduction, followed by centrifugal dehydration and drying. Also,
It is also possible to directly dry the latex, such as by spray drying, to remove the core-shell polymer.

The average particle diameter of the core-shell polymer of the present invention obtained by the above method is preferably in the range of 0.2 to 2 P, particularly in the range of 0.2 to 0.5 P. If the particle size is smaller than 0.2, the effect of eliminating pearlescent luster will be insufficient, and if it is larger than diphosphorus, the impact resistance will decrease.

The thermoplastic resin composition of the present invention has aromatic polycarbonate resin (A)/polymethyl methacrylate (B) =
20/80 to 70/30 (weight ratio), and this 10
1 to 10 parts of core-shell polymer (C) per 0 parts by weight
Add parts by weight. If the amount of component (A) is more than the above range, the improvement in surface hardness will be insufficient, and if it is less than the above range, the impact resistance will be insufficient. Furthermore, if the content of the ([1,) component is more than the above range, the heat resistance represented by the heat distortion temperature will be insufficient, and if it is less, the removal of pearlescent luster will be insufficient.

The thermoplastic resin composition of the present invention as described above may contain various additives such as stabilizers, pigments, dyes, flame retardants, and lubricants, reinforcing materials such as inorganic or organic fiber substances, glass beads, etc., as desired. Various fillers may be blended, and other resin components may also be blended within a range that does not impair the characteristics of the present invention.

〔Example〕

This will be explained below using examples.

Note that "%" and "molecular weight" are based on weight unless otherwise specified.

Synthesis Example 1 In a polymerization vessel equipped with a reflux condenser, 450 parts of deionized water and 1% aqueous solution of dioctyl sulfosuccinate sodium salt 20
and 40 parts of a 1% aqueous solution of sodium hydrogen carbonate were added, and the temperature was raised to 70° C. with stirring under a nitrogen stream.

Add 40 parts of the monomer mixture shown in Table 1 below to 1
After dispersing for 0 minutes, 80 parts of 2% sodium persulfate aqueous solution was added to initiate seed polymerization. Subsequently, a monomer emulsion consisting of the remaining 760 parts of the first-stage monomer mixture, 450 parts of a 1% aqueous solution of dioctyl sulfosuccinate sodium salt, and 40 parts of a 1% aqueous solution of sodium bicarbonate was continuously fed over a period of 120 minutes. did.

After raising the temperature to 90°C and aging for 60 minutes, the mixture was cooled to 70°C and proceeded to the second stage of polymerization. 2% sodium persulfate aqueous solution
Then, 200 parts of the second stage monomer mixture shown in Table 1, 90 parts of a 1% aqueous solution of dioctyl sulfosuccinate sodium salt, and 20 parts of a 1% aqueous solution of hydrogen carbonate) were added. The monomer emulsion was continuously fed over 45 minutes.

After raising the temperature to 90°C and aging for 60 minutes, the reaction solution was cooled and aged for 30 minutes.
The core-shell polymer latex was obtained by filtration using a stainless wire mesh with 0 mesh.

This latex was spray-dried at an inlet temperature of 140°C and an outlet temperature of 70°C to obtain a core-shell polymer powder (hereinafter referred to as (A)) having carboxyl groups in the shell.

Synthesis Example 2.3 Core-shell polymer powders having hydroxyl groups (hereinafter referred to as (B) and Synthesis Example 2) or core-shell polymer powder without functional groups (hereinafter referred to as (C)) Synthesis Example 3 Examples 1 to 9 and Comparative Examples 1 to 3 Aromatic polycarbonate resin made from bisphenol A (Mitsubishi Gas Co., Ltd.) Manufactured by Kagaku ■, trade name Newpilon S-30
00, molecular weight 23.000. S-3000), polymethyl methacrylate resin (manufactured by Mitsubishi Rayon ■, trade name: ACRYPELLA) VA, PMMA) and core-shell polymers obtained in Synthesis Examples 1 to 3 ((A), (
After mixing B) and (C)) in the ratio shown in Table 2,
It was extruded into pellets using a single screw extruder.

The obtained pellet was injection molded to make a test piece, and the heat deformation temperature (load: 18.6 kg/cnf, unit: °C, hereinafter referred to as HOT), Izod impact strength (thickness: 3.2 cm, notched) , unit: kg-cm/cm (hereinafter referred to as IZ), surface hardness (measurement of pencil hardness), and presence or absence of pearlescent luster (O: not present at all, △: slightly observed, ×
: Yes) The results are shown in Table 2.

For comparison, when the core-shell polymer described above was not used (Comparative Example 1), a polyester elastomer (manufactured by ■, Perbrene P-30B, hereinafter referred to as P-30B) (Comparative Example 2) and MBS resin (manufactured by Mitsubishi Rayon ■,
Product name: Metabrent 800 (hereinafter referred to as To800)
Table 2 shows the results for the case where (Comparative Example 3) was used in the same manner as in the example.

[Operation and effects of the invention]

As is clear from the above detailed description and examples,
The composition of the present invention is a thermoplastic resin composition that eliminates pearlescent luster by using an acrylic core-shell polymer, has excellent heat resistance and impact resistance, and has improved surface hardness.

Therefore, the present invention has the advantages of a composition of aromatic polycarbonate and methyl methacrylate, and can be applied to fields where it could not be used in the past due to its pearlescent luster, making it an extremely meaningful resin composition. .

Claims (1)

[Claims] 1 (A) 20 to 70 parts by weight of aromatic polycarbonate resin and (B) 80 to 3 parts by weight of polymethyl methacrylate resin
(C) to 100 parts by weight of a resin composition consisting of 0 parts by weight.
, a thermoplastic resin composition comprising 1 to 10 parts by weight of an acrylic core-shell polymer. 2. The thermoplastic resin composition according to claim 1, wherein the acrylic core-shell polymer (C) comprises a rubbery polymer core and a glassy polymer shell modified with a polar functional group. 3. The thermoplastic resin composition according to claim 2, wherein the polar functional group is a carboxyl group or a hydroxyl group. 4. The thermoplastic resin composition according to claim 1, 2 or 3, wherein the acrylic core-shell polymer (C) has an average particle diameter in the range of 0.2 to 0.5 μm.