JP3131949B2 - Polyester resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin composition. More specifically, the present invention relates to a thermoplastic polyester resin composition which is small in warpage during molding and has excellent mechanical and thermal properties.

[0002]

2. Description of the Related Art Thermoplastic polyester resins reinforced with a fibrous reinforcing material such as glass fiber, for example, polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), have mechanical, electrical, and physical properties.
It has excellent chemical resistance and dimensional stability.
It is used in a wide variety of applications, such as machine parts and automobile parts.

However, the thermoplastic polyester resin originally has a large molding shrinkage at the time of molding, and when reinforced with a fibrous reinforcement such as glass fiber, the arrangement direction (flow direction) of the fibrous reinforcement is different from the arrangement direction. There is a large difference in the molding shrinkage in the direction perpendicular to the direction (anisotropic), and there is a drawback that the molded product is likely to be warped. For this reason, large warpage occurs during molding of plate-shaped molded products, box-shaped molded products, molded products with large variations in wall thickness, etc., and it is not possible to obtain molded products that can withstand practical use in appearance. Has significant restrictions.

[0004] Therefore, a number of warp prevention measures have been proposed. As a general method, reinforced PBT or glass beads reinforced with a fibrous reinforcing material having a small aspect ratio (usually 5 or less), such as milled glass, has been proposed. There is a reinforced PBT reinforced with a spherical reinforcing material having no orientation at all, or a PBT reinforced with a plate-like reinforcing material such as mica.
However, although these are effective in preventing warpage during molding, their thermal and mechanical properties are significantly reduced, which is not practical. In addition, combinations of these small-aspect-ratio reinforcing materials, spherical reinforcing materials, plate-like reinforcing materials and fibrous reinforcing materials have been proposed. Requires 5% by weight or more, preferably 10% by weight or more of a fibrous reinforcing material, and such a thermoplastic polyester resin composition has almost no effect in preventing warpage during molding.

On the other hand, besides preventing warpage by selecting a reinforcing material, a method has been proposed in which an amorphous thermoplastic resin having a small molding shrinkage is further blended with a thermoplastic polyester reinforced by a fibrous reinforcing material. . However,
The method of blending an amorphous thermoplastic polymer has a low effect of preventing warpage during molding. To completely suppress warpage during molding, it is necessary to use an extremely large amount of amorphous thermoplastic resin. There is. However, when the blend amount of the amorphous thermoplastic resin increases, the chemical resistance, mechanical properties,
The decrease in thermal properties is extremely large, and it is difficult to say that a reinforced thermoplastic polyester resin composition is used.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a thermoplastic polyester reinforced with a fibrous reinforcement such as glass fiber, which impairs the excellent mechanical, electrical, physical and chemical resistance of the thermoplastic polyester. It is another object of the present invention to prevent warpage during molding.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and found that a fibrous reinforcing material such as glass fiber, a spherical reinforcing material, and a plate-like reinforcing material were added to a thermoplastic polyester resin. The combination of the material and the amorphous polymer has led to the completion of a reinforced thermoplastic polyester-based resin composition in which warpage during molding is extremely small.

That is, the present invention provides a thermoplastic polyester resin (A), a spherical reinforcing material (B), a weight average
The diameter is 50-700 microns and the aspect ratio is 20-
300 plate-like reinforcements (C) , fibrous reinforcements (D),
Styrene / butadiene / acrylonitrile copolymer,
One kind selected from cryl elastic body and diene elastic body
The present invention relates to a polyester resin composition containing the above amorphous polymer (E).

[0009]

The thermoplastic polyester resin (A) used in the present invention comprises terephthalic acid or esters thereof, ethylene glycol, propylene glycol, butanediol, pentanediol, neopentyl glycol, hexanediol, octanediol, decane. Diol,
Thermoplastic polyester obtained from glycols such as cyclohexanedimethanol, hydroquinone, bisphenol A, 2,2-bis (4-hydroxyethoxyphenyl) propane, 1,4-dimethyloltetrabromobenzene or TBA-EO. It is.

Preferred thermoplastic polyester resins (A) used in the present invention include polyethylene terephthalate and polybutylene terephthalate.
Furthermore, the intrinsic viscosity [η] measured at 30 ° C. in a mixed solvent of phenol and ethane tetrachloride in a weight ratio of 6: 4 is 0.3.
Those having a range of 3 to 1.5 dl / g are preferable. The thermoplastic polyester resin has an intrinsic viscosity [η] of 0.3.
When it is 1.5 dl / g, it is more excellent in mechanical strength, fluidity at the time of melting, surface gloss and the like.

The spherical reinforcing material (B) used in the present invention has a substantially spherical shape with a weight average particle size of 10 to 100 microns, and is usually selected from alkali glass beads and non-alkali glass beads. Preferably, alkali-free glass beads are preferable to minimize the decomposition of the thermoplastic polyester, and further, to improve the adhesion between the thermoplastic polyester and the spherical reinforcing material, a silane-based coupling agent, a titanium-based coupling agent, and the like. For example, aminosilanes such as γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyldimethoxymethylsilane; -Glycidoxypropyltrimethoxysilane, γ-glylicidoxypropylethoxysilane, β- (3,4-epoxycyclohexyl)
Epoxysilanes such as ethyltrimethoxysilane: those that have been surface-treated with coupling agents such as titanium-based coupling agents such as isopropyl tristearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, and tetraisopropyl bis (dioctyl phosphite) titanate. preferable.

The weight average particle size of the spherical reinforcing material (B) is 10 to
100 μm, particularly preferably 10 to 80 μm, is also preferable in order to prevent the effect of preventing warpage during molding and not to deteriorate the appearance of the molded product.

The amount of the spherical reinforcing material (B) used is in the range of 5 to 50% by weight, preferably 5 to 40% by weight, and the effect of preventing warpage during molding and the fluidity during molding are good. .

The plate-like reinforcing material (C) used in the present invention comprises :
The weight average flake diameter is 50-700 microns
It is an extremely thin plate-like reinforcing material having an impact ratio of 20 to 300 ,
Usually selected from alkali glass flakes, alkali-free glass flakes, gold mica, black mica, white mica, and silk mica. Preferably, alkali-free glass flakes, gold mica, to minimize decomposition of the thermoplastic polyester,
Black mica, white mica, and silk mica are preferred, and those that have been surface-treated with a coupling agent such as the above-mentioned silane or titanium to improve the adhesion between the thermoplastic polyester and the plate-like reinforcing material are preferred.

The weight average flake diameter of the plate-like reinforcing material (C) is
Weight average aspect ratio of 20 to 50 to 700 microns
When it is 300 , the effect of preventing warpage during molding is excellent, and the appearance of the molded product is also good.

The amount of the plate-like reinforcing material (C) used is 5 to 5
0% by weight, preferably 5 to 40% by weight. In the range where the amount is used, the effect of preventing warpage during molding, the fluidity during molding, and the finish of the molded product are improved.

The fibrous reinforcing material (D) used in the present invention is usually selected from glass fibers and carbon fibers, and preferably has a weight average aspect ratio of 10 or more. Further, in order to improve the adhesion between the thermoplastic polyester and the fibrous reinforcing material, those treated with a coupling agent such as silane or titanium described above are preferable. Further, it is preferable that the fibrous reinforcing material is treated with a sizing agent such as urethane type or epoxy type in order to improve the sizing property of the fibrous reinforcing material.

The amount of the fibrous reinforcing material (D) used is 5 to 5.
50% by weight, preferably in the range of 5 to 40% by weight, is excellent in effects such as heat resistance, mechanical properties, and prevention of warpage during molding.

The total amount of the spherical reinforcing material (B), the plate-like reinforcing material (C) and the fibrous reinforcing material (D) is 15 to 60% by weight, preferably 15 to 50% by weight. Within such a range, the molded article is excellent in effects such as warpage prevention, heat resistance, mechanical properties, fluidity during molding, and finished product.

The amorphous polymer (E) used in the present invention
Is styrene / butadiene / acrylonitrile copolymer
And at least one polymer selected from a body , an acrylic elastic body and a diene elastic body.

Styrene / butadiene / acrylonitrile
The copolymer preferably contains at least 50% by weight of styrene . Among them, styrene / butadiene / acrylonitrile copolymer containing 50% by weight or more of styrene and 5 to 25% by weight of butadiene and 30% by weight or less of acrylonitrile is preferred. Polymers are preferred.

The acrylic elastomer is obtained by polymerizing or copolymerizing at least one acrylate ester represented by the following general formula: CH 2 ＣＨCHCOOR (where R represents an alkyl group of C ₁ to C ₈ ). And a rubber-like elastic body comprising 75 to 99.8% by weight of an acrylic acid ester monomer.

Specific examples thereof include ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, and glycidyl methacrylate containing an epoxy group. It was done.

The acrylic elastomer used in the present invention is obtained by copolymerizing a monomer system comprising a monomer for crosslinking and a monomer for graft bonding as another monomer with the acrylic ester represented by the above general formula. You can do anything you like.

The crosslinking monomer has a plurality of double bonds,
And all of them are polyethylene unsaturated monomers such as butylene diacrylate: dimethacrylate: divinylbenzene: trimethylolpropane triacrylate and trimethacrylate, and similar compounds, all polymerizing at substantially the same rate. . Of these, butylene diacrylate is most preferred.

The graft-bonding monomer has a plurality of double bonds, at least one of which is a polyethylenically unsaturated monomer which is polymerized at a polymerization rate substantially different from other double bonds. . Examples of these are allyl acrylate, allyl methacrylate, diallyl maleate,
There are diallyl fumarate, diallyl itaconate, allyl acid maleate, allyl acid fumarate and allyl acid fumarate. Preferred monomers for graft bonding include allyl methacrylate and diallyl maleate.

Further, in the present invention, a C ₁ -C ₁₆ alkyl acrylate, styrene,
An acrylic elastic body composed of a multilayer composite copolymer having a hard thermoplastic layer in the outermost layer obtained by polymerizing a monomer system selected from the group consisting of acrylonitrile, lower acrylic acrylate and allyl methacrylate may be used.

The diene-based elastic material used in the present invention is a polymer containing a butadiene component as a rubbery component, and preferably has a butadiene component in an amount of 40 to 80% by weight. Styrene, as a monomer copolymerizable with this rubbery component,
α-methylstyrene, vinyltoluene, trimethylstyrene, divinylbenzene, methyl methacrylate, ethyl methacrylate, propyl methacrylate, acrylonitrile, methacrylonitrile, and the like, particularly styrene,
Acrylic nitrile and methyl methacrylate are preferred,
Two or more of these may be copolymerized.

The amount of the amorphous polymer (E) used is 3 to
When the content is 40% by weight, preferably 5 to 30% by weight, the effect of preventing warpage during molding, chemical resistance, heat resistance, mechanical properties and the like are excellent.

The thermoplastic polyester resin (A)
And the amorphous polymer (E) are mixed in such a manner that warpage is prevented,
Considering the effects such as heat resistance and mechanical properties, (A) /
(E) = 50/50 to 95/5 (weight ratio), preferably (A) / (E) = 60/40 to 90/10 (weight ratio).

In the composition of the present invention, in addition to the above essential components, hindered phenol-based heat stabilizers, phosphate stabilizers, sulfur-based stabilizers, etc. may be used as heat stabilizers. A suitable amount is 0.01 to 10% by weight, preferably 0.1 to 5% by weight. Also, the combined use of two or more of these heat stabilizers is preferable because the heat stability is improved.

As the lubricant, an aliphatic ester lubricant, an olefin wax, a metal soap or the like may be used. The amount used is 0.01 to 10% by weight, preferably 0.1 to 10% by weight.
A range of 1 to 5% by weight is suitable. In particular, aliphatic ester lubricants are preferable. As the aliphatic ester lubricant, butyl stearate, monoglyceride stearate,
Sorbitan stearate, montanic acid aliphatic 2
And higher fatty acid esters such as polyhydric alcohol esters (and partially saponified products thereof). Of these, partially saponified montanic acid esters are preferred.

Further, in the composition of the present invention, a flame retardant, a nucleating agent, a pigment, a dye, a plasticizer, an ultraviolet absorber, a foaming agent, a coupling agent, or the like may be used as other additives. A good filler may be used together with a reinforcing filler as long as the properties are not impaired. As the reinforcing filler, known and commonly used fillers can be used. Among them, typical ones are potassium titanate fiber, metal fiber, ceramic fiber, aramid fiber, PPS fiber, calcium carbonate, calcium silicate, magnesium silicate. , Calcium sulfate, barium sulfate, iron oxide, graphite, carbon black, asbestos, ceramic powder, metal flake and the like. Further, these reinforcing materials are preferably surface-treated with a silane coupling agent, a titanium-based coupling agent, or the like.

The method for producing the composition of the present invention is not particularly limited, but preferably, the components of the composition are uniformly mixed in advance, and then uniaxial or multiaxial at a temperature equal to or higher than the melting point of the thermoplastic polyester resin. Melt kneading using an extruder,
Then, it is cut with a cutter and provided as pellets.

The composition thus obtained can be molded by any known method such as injection molding and extrusion molding. The molded product has extremely small warpage, and has heat resistance, mechanical properties, chemical resistance, and molding resistance. It has excellent industrial properties and is of great industrial value, and can be used for molding applications such as mechanical mechanism parts, electric / electronic parts, and automobile parts.

[0036]

The present invention will be further described below with reference to examples. However, the present invention is not limited to the following examples.

[Examples 1 to 7] [η] was 0.9 dl /
g of polybutylene terephthalate (hereinafter abbreviated as PBT) resin 100 parts by weight, the fibrous reinforcing material, the spherical reinforcing material, the plate-like reinforcing material, and the polymer shown in Tables 1 and 2 were uniformly mixed in advance. Thereafter, the mixture was kneaded by an extruder equipped with a 65 mm single screw vent set at 250 ° C., pulled out as a strand, cooled, cut with a cutter, and subjected to PB
A T-resin compound pellet was obtained.

From the pellets, using a screw-in-line injection molding machine with a molding pressure of 50 t, a thickness of 1.6 m was used.
m, a disk-shaped test piece of a side gate having a diameter of 100 mm was prepared. The injection molding conditions were as follows: molding temperature: 260
° C, mold temperature: 60 ° C, injection speed: medium speed, injection pressure: primary pressure / secondary pressure = 140/30 to 70 (kg / cm ² ). Using this disc-shaped test piece, immediately after molding And 15
The warp height of the molded article after annealing at 0 ° C. for 1 hour was measured. The warpage was calculated from the diameter of the disk and the height of the disk using the following equation.

[0039]

Further, using the same injection molding machine, 12.5 ×
Test pieces of 125 × 3 mm square bars were prepared. still,
The injection molding conditions were as follows: molding temperature: 260 ° C., mold temperature: 60
° C, injection speed: medium speed, injection pressure: primary pressure / secondary pressure =
140/50 (kg / cm ² ). Using this square bar, the bending strength and bending elongation, the heat deformation temperature under a load of 18.6 kg / cm ² , and the finished product were examined.

Further, preliminary drying using the obtained pellets:
140 ° C / 2 hours, Measurement temperature: 265 ° C, Measurement load: 2
The melt flow rate (hereinafter, abbreviated as MFR) was measured at a hold time of 5 minutes and 15 minutes under the condition of 160 g.

Tables 1 and 2 show the test results in the above examples.
Shown in

In the following table, glass fiber: glass fiber RES03T made by Nippon Glass Fiber
P60 Carbon fiber: Toho Veslon PAN system, Vesfight HTAC-6 G beads: Toshiba Barotini glass beads EGB73
1B (weight average particle size: 18 microns) G flake: Nippon Glass Fiber glass flake REF60
0 (weight average flake diameter: 600 microns, weight average aspect ratio: 200) ABS: Nippon Synthetic Rubber ABSJSR10NP Mica: Kuraray mica 200K1 (weight average flake diameter: 90 microns, weight average aspect ratio: 50) Acrylic rubber: EXL2311 butadiene rubber manufactured by Kureha Chemical: BTA manufactured by Kureha Chemical was used.

[0044]

[Table 1]

[0045]

[Table 2]

[Comparative Examples 1 to 8] In the same manner as in the examples, similar tests were conducted for various compositions to be compared. Tables 3 and 4 show test results in Comparative Examples.

In Tables 3 and 4, talc: Talc SS manufactured by Nippon Talc Low density PP: Mitsubishi Noblen MG3B manufactured by Mitsubishi Yuka PC: Polycarbonate Novalex 702 manufactured by Mitsubishi Kasei
5A Phenoxy: Phenoxy resin phenothote Y manufactured by Toto Kasei
P-50.

[0048]

[Table 3]

[0049]

[Table 4]

From the comparison between the examples and the comparative examples, it can be seen that the thermoplastic polyester resin composition of the present invention has a small warpage during molding and is excellent in heat resistance, mechanical properties and chemical resistance.

[0051]

Industrial Applicability The polyester resin composition of the present invention has a small warpage during molding and is excellent in heat resistance, mechanical properties and chemical resistance, and can be used in the fields of electric / electronic parts and automobile parts. .

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-6250 (JP, A) JP-A-53-137251 (JP, A) JP-A-4-4249 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C08L 67/00-67/04

Claims (3)

(57) [Claims] 1. A thermoplastic polyester resin (A), a spherical reinforcing material (B), and a weight average flake diameter of 50 to 700.
A plate-like reinforcement (C) having a micron size and the same aspect ratio of 20 to 300 , a fibrous reinforcement (D), and styrene / butadiene.
/ Acrylonitrile copolymer, acrylic elastomer and
A polyester resin composition comprising at least one amorphous polymer (E) selected from diene-based elastic bodies . 2. The composition according to claim 1, wherein the spherical reinforcing material (B) is a glass bead. 3. The composition according to claim 1, wherein the plate-like reinforcing material (C) is glass flake or mica.