JP3278082B2 - Thermoplastic resin composition and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition which does not cause strand breakage during the production of a resin composition and which has an excellent balance of physical properties such as impact resistance, surface appearance and dimensional stability, and its thermoplastic resin. The present invention relates to a method for producing a thermoplastic resin composition which can be applied to obtain a composition.

[0002]

2. Description of the Related Art Thermoplastic polyesters are generally excellent in oxidation resistance and solvent resistance, but due to their high crystallinity, warpage, sink marks, etc. occur, and the dimensional stability of molded products is particularly poor. There is a disadvantage of poor heat resistance. On the other hand, polycarbonate resin is excellent in impact resistance and heat resistance, but is poor in solvent resistance, and molding is difficult due to high melt viscosity, residual stress during molding is easy to occur, and the disadvantage of poor solvent resistance is further increased. You.

[0003] In order to compensate for the mutual disadvantages of thermoplastic polyester and polycarbonate, there is a method of melt-blending both (for example, Japanese Patent Publication No. 36-14035). The moldability and the solvent resistance are also improved, but the impact strength is significantly reduced. In addition, strand breakage is likely to occur during the production of the resin composition, resulting in poor productivity.

Further, ABS or MBS is used as a third component.
A suitable elastomer such as a graft copolymer (for example, JP-B-55-9435) or an acid-modified EPR (for example, JP-A-57-92045) is added and melt-mixed to obtain a thermoplastic resin composition having high impact strength. It is widely used as a material for exterior parts of various industrial parts, home appliances and vehicles. However, even if the molded article has no residual distortion during molding, annealing at a temperature close to the heat distortion temperature does not improve the problem that the dimensional change of the molded article due to progress of crystallization of the polyester component, It is not suitable as a material for precision parts or parts that require a heat treatment step for painting. Further, the disadvantage that strand breakage is likely to occur during the production of the resin composition and the productivity is deteriorated remains unsolved.

An inorganic filler is blended with a thermoplastic resin composition comprising a thermoplastic polyester resin, a polycarbonate resin, and a specific graft copolymer in order to improve the above-mentioned drawbacks (for example, see JP-A-60-92350, Japanese Patent Application Laid-Open No. 63-132961), and attempts have been made to reduce dimensional changes such as warpage caused by annealing. However, when an inorganic filler is blended, adverse effects such as a reduction in impact strength of the resin composition and a deterioration in appearance are caused.

[0006] On the other hand, most of the thermoplastic polyester resin used as a molding material contains glass fiber, and the glass fiber reinforced polyester resin contains a specific nucleating agent (for example, Japanese Patent Publication No. 44-7542) and has a dimension. It is known that the stability, the injection molding cycle and the heat resistance are improved. Crystal nucleating agents used in glass fiber reinforced polyester resins are roughly classified into organic crystal nucleating agents typified by metal salts of organic carboxylic acids and inorganic crystal nucleating agents typified by talc and clay. In addition to the crystal nucleating agent, a glycol derivative represented by polyethylene glycol or the like is used as a crystallization accelerator suitable for a glass fiber reinforced polyester resin. However, in the case of the glass fiber reinforced polyester resin, the problems of dimensional stability, injection molding cycle, and heat resistance are improved, but the surface gloss and appearance of the molded product are deteriorated. Sometimes extruder or molding machine cylinder,
There is a problem that metals such as screws and molds are worn.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by solving the above-mentioned drawbacks of the thermoplastic resin composition comprising a thermoplastic polyester resin and a polycarbonate resin. An object of the present invention is to achieve improvements such as a change in dimensions due to annealing, a decrease in impact strength, a poor surface appearance of a molded product, or a broken strand during production of a resin composition. Therefore, the present inventor improved the crystallization rate of the polyester component by further blending a nucleating agent with a thermoplastic resin composition comprising a thermoplastic polyester resin, a polycarbonate resin, and a specific graft copolymer, and annealed. Reduces the dimensional change caused by
Further, the present invention has been completed in which the resin composition has good impact strength and good surface appearance.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a thermoplastic resin composition and a method for producing the same, and has the following structure to solve the above-mentioned problems. (A) 9 to 60% by weight of a thermoplastic polyester resin, (B) 29 to 90% by weight of a polycarbonate resin, and (C) a rubbery polymer containing an aromatic vinyl monomer, a vinyl cyanide monomer, and a methacrylic acid ester. Graft copolymer 1 obtained by graft copolymerizing one or more vinyl monomers selected from the group consisting of
-40% by weight mixture, (A) + (B) + (C) = 10
0 parts by weight of (D) an inorganic crystal nucleating agent (however,
Excluding) 0.1 to 10 parts by weight of a thermoplastic resin composition, and (D) an inorganic crystal nucleating agent added to (A) a thermoplastic polyester resin in the production of the thermoplastic resin composition, followed by melt-kneading. Further, there is a production method in which (B) the polycarbonate resin and (C) the graft copolymer are melt-kneaded with the molten mixture.

Hereinafter, the present invention will be described in detail. The thermoplastic polyester resin (A) that can be used in the present invention is not particularly limited as long as it has an alkylene terephthalate repeating unit as a main component, and may be a copolymer with another copolymerizable component or a copolymer with another resin. It may be a block resin. As the alkylene terephthalate repeating unit,
Examples include ethylene terephthalate, tetramethylene terephthalate, and 1,4-cyclohexylene terephthalate. Examples of the copolymerizable component include dicarboxylic acids such as isophthalic acid and diols such as 1,3-propanediol. Is a polyalkylene oxide such as polyethylene oxide. Specific examples include polyethylene terephthalate resin, polybutylene terephthalate resin, and poly-1,4-cyclohexylene terephthalate, and polyethylene terephthalate resin is particularly preferred.

The intrinsic viscosity of the polyethylene terephthalate resin is such that the value measured at 20 ° C. using phenol / tetrachloroethane = 6/4 as a solvent is in the range of 0.5 to 1.5, particularly 0.7 to 1. A range of 2 is preferred.

The polycarbonate resin (B) which can be used in the present invention is not particularly limited as long as it is made from an aromatic hydroxy compound. Specifically, 2,2'-bis (4
-Dihydroxydiphenyl) -propane (bisphenol A) polycarbonate is preferred. The viscosity average molecular weight of the polycarbonate resin is 1500 from the point of impact strength.
Must be 0 or more, 20000 to 4000
It is preferably in the range of 0.

The graft copolymer (C) which can be used in the present invention is at least one vinyl monomer selected from the group consisting of an aromatic vinyl monomer, a vinyl cyanide monomer and a methacrylate ester. Is a graft copolymer obtained by graft-copolymerizing a rubber-like polymer with a rubber-like polymer.

Examples of the rubbery polymer include butadiene polymer, copolymer of butadiene and a vinyl monomer copolymerizable therewith, ethylene-propylene copolymer, and ethylene-propylene copolymer.
A propylene-diene copolymer, a block copolymer of butadiene and aromatic vinyl, an acrylate ester copolymer, and a copolymer of an acrylate ester and a vinyl monomer copolymerizable therewith are used.

The aromatic vinyl monomer includes, for example, styrene monomers such as styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, chlorostyrene and the like and their substituted monomers.

Examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile and the like. Examples of the methacrylic acid ester include a methyl ester and an ethyl ester.

In the graft copolymer (C), 0 to 70 mol% of an aromatic vinyl monomer, 0 to 60 mol% of a vinyl cyanide monomer and 0 to 100 mol% of a methacrylate ester.
An ABS graft polymer, an MBS graft copolymer, an AES graft copolymer, or a mixture of two or more of the above copolymers, obtained by graft-copolymerizing a monomer mixture of mol% with 30 to 80 parts by weight of a rubbery polymer. It may be a mixture, especially AB
S-graft copolymers and MBS-graft copolymers are preferred.

The inorganic crystal nucleating agent (D) that can be used in the present invention is not particularly limited as long as it is an inorganic compound having good wettability and cleavage for a thermoplastic polyester in a molten state. Those having a size of 10 μm or less are preferred. Specifically, talc, boron nitride , montmorillonite, graphite and the like can be mentioned, and talc and boron nitride having a particle size of about 1 μm are particularly preferable.

The silane coupling agent that can be used in the present invention is represented by the following general formula R ₁ -Si- (OR ₂ ) ₃ (-R ₁ : functional organic group, -OR ₂ : hydrolyzable alkoxyl group). Those represented are preferred. In particular,
γ-glycidoxypropyltrimethylsilane, β-
(3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-aminopropyltrimethylsilane, N-
β- (aminoethyl) -γ-aminopropyltrimethoxysilane and the like.

In the present invention, in addition to the inorganic crystal nucleating agent (D),
As a crystallization accelerator for polyethylene terephthalate or polybutylene terephthalate, a compound generally known can be used. Specific examples include dibenzoic acid esters, diphenyl esters, and dialkyl esters of aliphatic polyols such as ethylene glycol, triethylene glycol, neopentyl glycol, pentaerythritol, and polyethylene glycol.

In the thermoplastic resin composition of the present invention, the proportions of (A) the thermoplastic polyester resin, (B) the polycarbonate resin, (C) the graft copolymer and (D) the inorganic crystal nucleating agent are as follows: Plastic polyester resin 9
-60% by weight, preferably 15-50% by weight, (B) 29-90% by weight, preferably 35% by weight of the polycarbonate resin.
To 80% by weight, (C) 1 to 40% by weight, preferably 3 to 30% by weight, and further (A) + (B)
+ (C) = 0.1 to 10 parts by weight, preferably 0.5 to 6 parts by weight of inorganic crystal nucleating agent (D) per 100 parts by weight. (A) If the thermoplastic polyester resin content is less than 9% by weight, the moldability and the solvent resistance are not improved, and 60% by weight.
If it exceeds, the impact strength decreases. When the content of the polycarbonate resin (B) is less than 29% by weight, the impact strength is reduced. When the content exceeds 90% by weight, the moldability and the solvent resistance are deteriorated.
When the amount of the (C) graft copolymer is less than 1% by weight, the impact strength is reduced, and when it exceeds 40% by weight, heat resistance, rigidity and moldability are reduced. (D) When the amount of the inorganic crystal nucleating agent is less than 0.1 part by weight, the dimensional stability and the strand property at the time of production are not improved. When the amount exceeds 10 parts by weight, the surface appearance deteriorates and the impact strength is lowered.

(D) The amount of the silane coupling agent coated on the surface of the inorganic crystal nucleating agent is
0.2 to 5 parts by weight, preferably 0.5 to 0 parts by weight
If it is less than 0.2 part by weight, the coupling with the thermoplastic polyester is not sufficient, and if it exceeds 5 parts by weight, the thermoplastic polyester is hydrolyzed and the molecular weight decreases.

The amount of the crystallization accelerator that can be used in the present invention ranges from 0 to 1 based on 100 parts by weight of the thermoplastic resin composition.
0 parts by weight, preferably in the range of 0 to 5 parts by weight. 10
When the amount exceeds the weight part, adverse effects such as an increase in volatile components at the time of molding and mold contamination are caused.

The production of the thermoplastic resin composition of the present invention can be carried out by using a commonly used kneader, for example, a Banbury mixer.
It can be produced by melt kneading with a Brabender, kneading roll, single screw or twin screw extruder. In addition, the production method is as follows: (A) thermoplastic polyester resin, (B) polycarbonate resin, (C) (C) graft copolymer, (D) inorganic crystal nucleating agent and other additives of the thermoplastic resin composition components. May be mixed and kneaded together, but (A) a thermoplastic polyester resin and (D) an inorganic crystal nucleating agent are first melt-kneaded, and then (B) a polycarbonate resin and (C) a graft copolymer. By further melting and kneading the above, excellent properties such as physical properties of the thermoplastic resin composition of the present invention and good strand condition during production can be exhibited.
The method of melt-kneading is not particularly limited as long as it is a method of applying a shear force capable of sufficiently kneading the molten resin as described above.

Specifically, a mixture of (A) a thermoplastic polyester resin and (D) an inorganic crystal nucleating agent in a Henschel mixer, a tumbler, or the like is mixed with a single or twin screw extruder, a kneading roll, a Brabender, The first stage of melt kneading is performed using a Banbury mixer or the like, and after granulation and drying, (B) a polycarbonate resin and (C) a rubbery graft copolymer are further added, and blended and melt kneaded in the same manner as in the first stage. Do 2
Although a production method having a melt kneading step of a stage is preferable, from the viewpoint of industrial productivity, (A) a thermoplastic polyester resin and (D) an inorganic crystal nucleating agent are kneaded with a single-screw or twin-screw extruder, It is particularly preferable to feed (B) the polycarbonate resin and (C) the graft copolymer from the middle of the extruder and further melt-knead them.

Further, after polymerization of the thermoplastic polyester resin (A), a thermoplastic polyester resin blended with an inorganic crystal nucleating agent in a granulation step, and (B) a polycarbonate resin and (C) a graft copolymer are uniaxially or It may be extruded with a twin screw extruder. In any method, after the melt-kneading of (A) the thermoplastic polyester resin and (D) the inorganic crystal nucleating agent, the melt-kneading of the other essential components (B) the polycarbonate resin and (C) the graft copolymer. The order is not limited.

The method of performing a silane coupling treatment on the inorganic crystal nucleating agent is not particularly limited as long as the silane coupling agent is uniformly coated on the surface of the crystal nucleating agent. And then gradually lower the silane coupling agent diluted in a water / alcohol mixed solvent, further continue stirring to mix, and finally dry the mixed solvent with a forced circulation dryer or the like. Such a method is recommended.

Further, the thermoplastic composition of the present invention may further contain an antioxidant, a flame retardant, an antistatic agent, an ultraviolet absorber, a lubricant, a coloring agent, a metal powder, and the like.

Further, other resins can be added according to the purpose. Specific examples include an AS resin, a styrene-maleimide copolymer, and a polyarylate resin. The addition amount of these resins is 50 parts by weight or less, preferably 0 parts by weight, per 100 parts by weight of the thermoplastic polyester resin (A).
-30 parts by weight is desirable.

[0029]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the invention thereto. Examples 1 to 10 and Comparative Examples 1 to 6 The thermoplastic resin, crystal nucleating agent and inorganic filler used in the present invention are shown. (1) Raw material of composition (a) Thermoplastic polyester resin: Commercially available polyethylene terephthalate resin "NEH-2050" [manufactured by Unitika Ltd.] (intrinsic viscosity: 0.77, solvent phenol / tetrachloroethane = 6/4) , Measured at a temperature of 20 ° C). A-1.

(B) Polycarbonate resin: Commercially available bisphenol A type polycarbonate resin "PANLITE L-1"
250 "[manufactured by Teijin Chemicals Ltd.] (viscosity average molecular weight 250
00) was used. B-1.

(C) Graft copolymer: 80 parts of polybutadiene latex (solid content 50%, average particle size 0.35 μm,
Gel content 90%), 1 part of sodium stearate, 0.1 part of sodium formaldehyde sulfoxylate,
0.03 part of EDTA tetrasodium salt, 0.003 part of ferrous sulfate and 200 parts of water were charged into an autoclave purged with nitrogen gas. After heating to 65 ° C., 50 parts of a monomer mixture consisting of 25% of acrylonitrile and 75% of styrene, 0.3 parts of t-dodecyl mercaptan and 0.2 parts of cumene hydroperoxide were added to 4 parts of
After the addition, polymerization was continued at 65 ° C. for 2 hours. The graft ratio was 78%, and the polymerization ratio was 97%. After adding an antioxidant to the obtained latex, salting out with calcium chloride, washing with water and drying, a white powdery copolymer was obtained. This graft copolymer is designated as C-1.
In addition, commercially available MBS resin “PARALOID EXL-260”
2 "[produced by Kureha Chemical Industry Co., Ltd.] and designated as C-2.

(D) Inorganic crystal nucleating agent, inorganic filler and organic crystal nucleating agent: commercially available talc “Microace P-4” (manufactured by Nippon Talc Co., Ltd.) as an inorganic crystal nucleating agent (average particle diameter) 1.5 μ) and the silane coupling agent “A-
187 "(γ-glycidoxypropyltrimethoxysilane) [manufactured by Nippon Unicar Co., Ltd.]. These are D-1 and D-2, respectively. Further, a commercially available boron nitride “boron nitride GP” (manufactured by Denki Kagaku Kogyo KK) was used. D-3. A commercially available titanium (IV) oxide rutile type as an inorganic filler and sodium benzoate (special grade reagent) [both manufactured by Wako Pure Chemical Industries, Ltd.] as an organic crystal nucleating agent are used, D-4 and D-5, respectively. I do.

(E) Crystallization accelerator: A commercially available polyethylene glycol "PEG-6000" (manufactured by NOF Corporation) was used. E-1.

(2) Production Method of Thermoplastic Resin Composition The production of the thermoplastic resin compositions in Examples 1 to 10 and Comparative Examples 1 to 6 was carried out in the proportions shown in Tables 1, 2 and 3. After mixing with a Henschel mixer, the mixture was mixed using a twin-screw extruder “TEM-35B” (manufactured by Toshiba Machine Co., Ltd.).
The mixture was melt-kneaded at 70 ° C., extruded and pelletized. Table 1, Table 2
In addition, the term "collective" as to the extrusion method in Table 3 means that all the compositions in the table are simultaneously compounded, extruded, and pelletized by the above method. The term "two-stage" means that in the first stage, only the thermoplastic polyester resin, the crystal nucleating agent and the crystallization accelerator or only the thermoplastic polyester resin and the crystal nucleating agent are blended, mixed and melt-kneaded by the above method. It is extruded, pelletized, dried, blended, mixed, melt-kneaded, extruded together with the polycarbonate resin and the graft copolymer in the same manner, and pelletized. From the pellets, a test piece for a physical property test was produced at a molding temperature of 270 ° C. and a mold temperature of 120 ° C. by an injection molding machine “IS-55EPN” [Toshiba Machine Co., Ltd.]. The results are shown in Tables 1, 2 and 3.
In addition, the thermoplastic polyester resin and the composition containing the same are subjected to a dehumidifying / drying machine “PO-50-OM / DMZ-170-OM” prior to melt-kneading and injection molding.
Matsui Seisakusho] at 120 ° C. for 5 hours or more.

(3) Measurement and Evaluation Methods for measuring various physical properties in Tables 1, 2 and 3 are as follows. (a) Gloss: 1 / thickness according to JIS K-7105
The specular gloss at 60 degrees was measured using an 8 "injection molded product. (B) Rigidity: 1/4" thick according to ASTM D-790
Was subjected to a bending test and the flexural modulus was measured. (c) Heat resistance: According to JIS K-7206, thickness 1 /
The Vicat softening point temperature of an 8 ″ injection molded product was measured under a load of 5 kgf. (E) Impact strength: Thickness 1 / according to ASTM D-256.
The notched Izod of an 8 ″ injection molded product was measured at an ambient temperature of 23 ° C.

(F) Stranding property at the time of extrusion: After the compositions shown in Tables 1, 2 and 3 are melt-kneaded by an extruder, they are discharged in the form of a strand from a nozzle, pelletized easily, and the appearance of the strand is improved. When it was good, it was evaluated as ◎, when it was easy to pelletize, it was evaluated as ○, and when it did not form a strand, it was evaluated as ×.

(G) Volumetric shrinkage of polyester component: It is considered that the biggest cause of dimensional change such as warpage of a molded product is that the polyester component crystallizes and shrinks during annealing. Therefore, as a measure of dimensional stability, attention was paid to the change in density of the molded article during annealing. Since the composition components other than polyester were composed of an amorphous resin containing a polycarbonate resin as a main component, the change in density during annealing was so small as to be negligible, and the volume shrinkage per polyester content was determined. Specifically, the pellets produced by the compositions and extrusion methods in Tables 1, 2 and 3
The mixture was pressed at 50 ° C. and 50 kgf / cm ² to form a film, and immediately put into a silicone oil bath at 130 ° C.
After putting in, 30 seconds, take out the film after 2 hours,
The density was measured by a density gradient tube method. The volume shrinkage per polyester component was calculated by the following equation (1).

(Equation 1)

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

[Table 3]

In the case of Comparative Example 1, when the molten resin was discharged from the nozzle of the extruder, it was difficult to form a pellet without forming a strand. Therefore, the bulk resin was cooled and formed into a pellet using a crusher.

[0042]

As shown in Tables 1, 2 and 3, the thermoplastic resin composition of the present invention does not cause strand breakage during production of the resin composition, and has impact resistance, surface appearance and dimensional stability. It has an excellent balance of physical properties and has high practical value as a material for various industrial parts and exterior parts of vehicles. In particular, it is useful in applications that require a heat treatment step for coating, since the dimensional change is small.

Claims (2)

(57) [Claims] (A) a thermoplastic polyester resin 9 to 60
Wt.%, (B) 29 to 90 wt.% Of a polycarbonate resin, and (C) a rubbery polymer, a vinyl-based monomer selected from the group consisting of an aromatic vinyl monomer, a vinyl cyanide monomer, and a methacrylate ester. 1 to 40% by weight of a graft copolymer obtained by graft copolymerizing at least one of
(B) + (C) = a thermoplastic resin composition comprising 0.1 to 10 parts by weight of (D) an inorganic crystal nucleating agent (excluding mica ) per 100 parts by weight. 2. An inorganic crystal nucleating agent (D) is added to (A) a thermoplastic polyester resin and melt-kneaded, and the molten mixture is further mixed with (B) a polycarbonate resin and (C)
Claims characterized by melt-kneading the graft copolymer
Item 10. A method for producing the thermoplastic resin composition according to Item 1 .