JPS61111355A - Polyester resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which gives moldings which little cause warpage and have excellent mechanical properties and surface appearance excellent in smoothness, by blending particulate Al2O3 with a thermoplastic polyester. CONSTITUTION:The titled compsn. is obtd. by blending 5-250pts.wt. particulate Al2O3 (having an average particle size of pref. 0.5-10mu) with 100pts.wt. thermoplastic polyester [e.g. polybutylene terephthalate or polybutylene (terephthalate/ adipate)]. Though the strength and the rigidity of polyester resins can be greatly improved by adding a reinforcing agent or a filler, they have disadvantages in that the resulting moldings cause warpage and surface smoothness is reduced. Though a method wherein a particulate filler (e.g. clay) is added to eliminate the problem of warpage has been proposed, mechanical properties are reduced and smoothness is not improved. By adding particulate Al2O3, a compsn. giving moldings which little cause warpage and having excellent mechanical properties and surface appearance can be obtd.

Description

[Detailed description of the invention] <Industrial application field> The present invention has less molding warpage, excellent mechanical properties, and
This invention relates to a polyester resin composition with excellent surface appearance.

<Conventional technology> Polyester resins, represented by polybutylene terephthalate, have significantly improved strength and rigidity by adding reinforcement and fillers, and are widely used in fields such as electrical machinery, automobiles, and building materials. However, reinforcing/filling agents that have such reinforcing effects, such as glass fiber and mica, are generally fibrous,
It is well known that since it has a plate shape, when it is made into a molded product, it has the disadvantage of giving the molded product a large warping deformation.

In addition, the appearance of the molded product loses its smoothness due to the filling of these fillers, and it cannot be used at all in applications where molded appearance and surface smoothness are important.

In order to improve molding warpage, granular fillers with low anisotropy (e.g. calcium carbonate, clay, diatomaceous earth, calcium metasilicate, talc, sericite, etc.) are used.
(for example, JP-A-53-121843 and JP-A-55-16049) have been proposed, but when the compositions obtained by these methods are made into molded products, the molding warpage may be reduced. Although a slight reduction effect is observed, the actual situation is that the mechanical properties are deteriorated, a practically sufficient effect cannot be obtained, and the surface smoothness is not improved at all.

<Problems to be Solved by the Invention> Therefore, the present inventors solved the drawbacks of these conventional techniques, namely, the extremely poor mechanical properties represented by impact resistance and the surface smoothness of the molded product. As a result of intensive research to obtain a polyester resin composition with less molding warpage, excellent mechanical properties such as impact resistance, and excellent surface smoothness of molded products, we developed a thermoplastic polyester resin and a specific shape. It has been discovered that the above object can be effectively achieved by a composition containing aluminum oxide having the following, and the present invention has been achieved.

<Means and effects for solving the problems> That is, the present invention is a polyester resin composition comprising 10 to 250 parts by weight of granular aluminum oxide mixed with 100 parts by weight of a thermoplastic preester, and also preferably As an embodiment, a polyester resin composition in which the liquefied aluminum has an average particle size in the range of 0.5 to 10 μm.

A polyester resin composition in which the thermoplastic polyester contains 3 to 50% by weight of an aliphatic dicarboxylic acid copolymerized polyester, and the thermoplastic polyester contains 0.5 to 40% by weight of a glycidyl group-containing olefin copolymer. The polyester resin composition and the thermoplastic preester contain 3 to 50% by weight of the polyester elastomer.
The object of the present invention is to provide a polyester resin composition containing the present invention, and a polyester resin composition in which the composition is a plating composition.

Thermoplastic polyester toxin used in the present invention, 90 mol%
The above is a polymer obtained by condensation polymerization of a dicarboxylic acid component, which is a terephthalic acid component, and a diol component.

The terephthalic acid component mentioned here is terephthalic acid and its ester-forming derivatives, and other dicarboxylic acid components used together with the terephthalic acid component include isophthalic acid, orthophthalic acid, and 2,6-naphthalenedicarboxylic acid.

1.5-naphthalenedicarboxylic acid, bis(p-carboxyphenyl)methane, anthracenedicarboxylic acid, 4.
Aromatic dicarboxylic acids such as 4'-diphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid, 5-sodium sulfoisophthalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid Preferred examples include aliphatic dicarboxylic acids such as 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and ester-forming derivatives thereof.

In addition, the diol component preferably has 2 to 20 carbon atoms.
aliphatic glycols such as, for example, specifically ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-bentanediol, 1,6-hexanediol, decamethylene glycol, cyclohexane dimetatool , cyclohexanediol, and ester-forming derivatives thereof.

Preferred specific examples of these polymers or copolymers include polybutylene terephthalate, bributylene (terephthalate/isophthalate), polybutylene (terephthalate/adipate), polybutylene (terephthalate/sebacate), and polybutylene (terephthalate/isophthalate).
Decane dicarboxylate), polyethylene terephthalate, polyethylene (terephthalate/isophthalate), polyethylene (terephthalate/adipate), polybutylene (terephthalate/5-sodium sulfoisophthalate), polyethylene (terephthalate 15-sodium isophthalate) ) etc., and polyethylene terephthalate, polybutylene (terephthalate/adipate), polybutylene (terephthalate/decanone carboxylate), polyethylene terephthalate, polyethylene (terephthalate/adipate), polybutylene (
Particularly preferably used are terephthalate (15-sodium sulfoisophthalate) and the like. Further, it is preferable that these thermoplastic polyesters have a relative viscosity of 12 to λ0, particularly 13 to L85 when a 5% O-chromitzenol solution is measured at 25°C.

1 Moreover, these can be used in a mixture of 211 or more.

The aluminum oxide used in the present invention is aluminum hydroxide (chemical formula Al(O
Powder particles obtained by appropriately grinding an aggregate of crystal grains of aluminum oxide produced by firing H) 3 or AhOs.3 (represented by 0) are preferably used.

The average particle size of these powdered aluminum oxide particles is 0.5
-10 .mu.m, particularly 0.7-6 .mu.m is preferably used, and L4-4 .mu.m provides particularly excellent effects.

In order to more significantly exhibit the effects of the present invention, it is preferable that the average particle size of aluminum oxide is in the range of 0.5 to 10 μm. Outside this range, when the average particle size is less than 0.5 μm, the surface smoothness is good. However, the impact resistance tends to be poor, and the warp deformation of the molded product tends to increase. When the average particle size exceeds 10 am, impact resistance and surface smoothness tend to be poor.

Furthermore, the particle size distribution of the particles herein is determined from the particle size distribution measured by the sedimentation balance method, and the average particle size is indicated by the particle size corresponding to the cumulative weight % of the particle size distribution of 50 weight %.

The amount of aluminum oxide added is preferably 5 to 250 parts by weight, particularly 30 to 100 parts by weight, per 100 parts by weight of the polyester resin. If the amount is less than 5 parts by weight, the rigidity of the resin will be insufficient. If it exceeds 250 parts by weight, the impact resistance will be poor and the surface smoothness of the molded product will be poor, which is not preferable.

When the thermoplastic polyester of the present invention is a mixed polyester containing an aliphatic dicarboxylic acid copolymerized preester, better impact resistance can be imparted.

The aliphatic dicarboxylic acid copolyester herein refers to 3 to 50 mol%, preferably 10% by mole of the dicarboxylic acid component.
It is a copolymer consisting of a dicarboxylic acid and a diol component, of which ~40 mol% is an aliphatic dicarboxylic acid component. The aliphatic dicarboxylic acid components mentioned here include adipic acid, sebacic acid, azelaic acid, decanedionic acid, dodecanedioic acid, hexadecanedionic acid, octadodecanedioic acid,
Preferred examples include dimer acids and ester-forming derivatives thereof.

Other dicarboxylic acid components used together with these aliphatic dicarboxylic acid components include terephthalic acid, isophthalic acid, ortho-7thalic acid, 2,6-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, bis(p-carboxyphenyl ) methane, anthracene dicarboxylic acid,
Aromatic dicarboxylic acids such as 4,4'-diphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc. Preferred examples include alicyclic dicarboxylic acids and ester-forming derivatives thereof. Diol components include aliphatic glycols having 2 to 20 carbon atoms, such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-bentanediol, 1,6-hexanediol, and decamethylene glycol. , cyclohexane dimetatool, cyclohexanediol, and ester-forming derivatives thereof.

Preferred specific examples of these copolymers include polybutylene (terephthalate/adipate), polybutylene (terephthalate/sebacate), polybutylene (terephthalate/decanedicarboxylate), polybutylene (terephthalate/isophthalate/sebacate), and polybutylene (terephthalate/isophthalate). /decafurecarboxylate), polyethylene (terephthalate/adipate), polyethylene (terephthalate/sebacate), and the like.

In addition, aliphatic dicarboxylic acid copolyester is 0.5
% 0-chlorophenol solution at 25° C. is preferably in the range of 12 to 2.0, particularly L3 to L85.

Also, these should not be used in combination of two or more types.
I can do it.

The content of these aliphatic dicarboxylic acid copolymers is preferably 3 to 50% by weight, particularly preferably 5 to 45% by weight, based on the total amount of the thermoplastic polyester and the aliphatic dicarboxylic acid copolymer. If it is less than 50% by weight, the effect of improving impact resistance will be small, and if it exceeds 50% by weight, the inherent heat resistance of thermoplastic polyester will be impaired, which is not preferable.

When the thermoplastic polyester of the present invention contains a glycidyl group-containing olefin copolymer, better impact resistance can be imparted.

The glycidyl group-containing olefin copolymer mentioned here preferably includes 50 to 99.5% by weight of α-ilefin and α-
, glycidyl ester of β-unsaturated carboxylic acid 50-0
．． 5% by weight and 0 to 49.5% by weight of vinyl acetate. The α-olefin referred to herein is preferably ethylene, propylene, buteno-1, etc., and ethylene is particularly preferably used. Also, α, β−
Glycidyl esters of unsaturated carboxylic acids are preferably compounds represented by the general formula (R in the formula represents a hydrogen atom or a lower alkyl group), and specifically include glycidyl acrylate, glycidyl methacrylate, glycidyl methacrylate, etc. Among them, glycidyl methacrylate is preferably used.

a, β in glycidyl group-containing olefin copolymer
- The copolymerization amount of glycidyl ester of unsaturated carboxylic acid is 0.5 to 50% by weight, especially 1 to 20% by weight! If the amount is less than 0.5% by weight, the effect of the present invention cannot be obtained, and if it exceeds 50% by weight, the composition tends to gel during melt mixing, which is not preferable.

Preferred examples of the olefin copolymer having a glycidyl group include ethylene/glycidyl methacrylate copolymer and ethylene/glycidyl methacrylate/vinyl acetate copolymer. The content of these glycidyl group-containing olefin copolymers is 0.5 to 40% by weight, particularly 1 to 30% by weight, based on the total amount of the thermoplastic polyester and the glycidyl group-containing olefin copolymer.
is preferred. If it is less than 0.51% by weight, the effect of improving impact resistance will be small, and if it exceeds 40% by weight, the inherent heat resistance of thermoplastic polyester will be impaired, which is not preferable.

In addition, when using a glycidyl group-containing olefin copolymer, organic sulfonic acid metal salts such as dodecylbenzenesulfonic acid sodium salt and dodecylsulfonic acid sodium salt, and alcohol sulfuric esters such as lauryl sulfate ester sodium salt should be used. A small amount of salt or the like can be added in combination, and the effect of improving impact resistance is further exhibited by the addition of these salts.

When the thermoplastic polyester of the present invention contains a polyester elastomer, better impact resistance can be imparted.

The polyester elastomer herein refers to a polyether ester block copolymer or a polyester/ester block copolymer, preferably having an aromatic polyester as a hard segment and a poly(alkylene oxide) glycol and/or aliphatic polyester as a soft segment. , a polyether ester O ester block copolymer. The aromatic polyester constituting the hard segment is a polymer obtained by condensation polymerization of a dicarboxylic acid component of which 60 mol % or more is a terephthalic acid component and a diol component. The dicarboxylic acid component and diol component other than terephthalic acid are the thermoplastic polyester.
Those mentioned here can be used.

Preferred examples of the aromatic polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene (terephthalate/isophthalate), polybutylene (terephthalate/isophthalate), and the like.

1. Specific examples of poly(alkylene oxide) glycol and aliphatic polyester that constitute the soft segment with CC include polyethylene glycol,
poly(1,2- and 1,3-propylene oxide) glycol, poly(tetramethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide,
Copolymer of ethylene oxide and tetrahydrofuran.

Preferred examples include polyethylene adipate, polybutylene adipate, poly-C-caprolactone, polyethylene sebacate, and polybutylene sepacate.

The ratio of the soft segment to the polyester hard segment of the polyester elastomer is 95% by weight.
15 to 10/90, particularly 1ζ90/10 to 30/7G is preferable.

Specific examples of polyester elastomers include polyethylene terephthalate and poly(tetramethylene oxide).
Glycol block copolymer, polyethylene terephthalate/isophthalate/poly(tetramethylene oxide) glycol block copolymer, poly(tetramethylene oxide) glycol block copolymer of polybutylene terephthalate, polybutylene terephthalate/isophthalate/poly(tetra methylene oxide) glycol block copolymer, polybutylene terephthalate/decane dicarboxylate poly(tetramethylene oxide) glycol block copolymer, polybutylene terephthalate/bori (propylene oxide/ethylene oxide) glycol block copolymer, polybutylene terephthalate /Isophthalate poly(propylene oxide/
(ethylene oxide) glycol block copolymer, polybutylene terephthalate/decane dicarboxylate,
Poly(propylene oxide/ethylene oxide) glycol block copolymer, polybutylene terephthalate
Poly(ethylene oxide) glycol block copolymer, polybutylene terephthalate/polyethylene adipate block copolymer, polybutylene terephthalate/butylene adipate block copolymer, polybutylene terephthalate/polybutylene separate block copolymer, polybutylene terephthalate/polybutylene adipate block copolymer, Preferred examples include poly-C-caprolactone block copolymers.

Among these polyester elastomers, especially polybutylene terephthalate and poly(tetramethylene oxide)
Glycol block copolymer, polybutylene terephthalate/isophthalate/poly(tetramethylene oxide) glycol block copolymer, polybutylene terephthalate/poly(propylene oxide/ethylene oxide) glycol block copolymer, polybutylene terephthalate/isophthalate/poly(tetramethylene oxide) glycol block copolymer, Poly(propylene oxide/
(ethylene oxide) glycol block copolymer, polybutylene terephthalate/polybutylene 7 dipate block copolymer, polybutylene terephthalate/poly-C
-Caprolactone block copolymers are preferably used.

The relative viscosity of these polyester elastomers measured in the same manner as the thermoplastic polyester was 14 to 4. O
In particular, those in the range of 16 to 3.0 are preferred.

Two or more of these -lyester elastomers can be used in combination.

The content of these polyester elastomers is preferably 3 to 50% by weight, particularly 5 to 45% by weight, based on the total amount of thermoplastic preester and polyester elastomer. If it is less than 3%, the effect of improving impact resistance will be small;
If it exceeds % by weight, the inherent heat resistance of the thermoplastic polyester will be impaired, which is not preferable.

In addition, the thermoplastic preester of the present invention is a polyester copolymerized with an aliphatic dicarboxylic acid, a glycidyl group-containing olefin copolymer, and a polyester elastomer.
5° to the total amount of thermoplastic polyester
It can also be contained at the same time in an amount of 0% by weight or less.

1 When preparing the composition of the present invention, zinc oxide, titanium oxide, magnesium oxide, silicon oxide, potassium titanate, magnesium carbonate, calcium carbonate,
Calcium/magnesium carbonate, calcium metasilicate, barium sulfate, talc, kaolin, clay, silica,
Fillers such as mica, asbestos, thyroid, glass beads, glass balloons, and shirasu balloons, and fibrous reinforcing agents such as glass fibers, metal fibers, and carbon fibers can be added as necessary.

Other conventional additives such as lubricants, mold release agents, nucleating agents, plasticizers, flame retardants, heat stabilizers, ultraviolet absorbers, pigments, dyes and other thermoplastic resins may also be added as necessary. You can also do it.

Although the method for producing the composition of the present invention is not limited to the above, for example, a method may be employed in which a raw material containing thermoplastic polyester, aluminum oxide, and other additives is supplied to a screw extruder and mixed by melt extrusion. can.

The composition of the present invention can be made into a molded article having a desired shape by employing any resin molding method such as injection molding, extrusion molding, or blow molding.

The composition of the present invention is a thermoplastic polyester blended with aluminum oxide particles, and when made into a molded product, it not only reduces warpage of the molded product, but also improves mechanical strength and surface smoothness. can be measured simultaneously.

As mentioned above, the fields of application where these compositions can be used include small deformation of molded products, high physical properties, and good appearance (surface smoothness).
Examples include precision mechanical parts such as watches and cameras, electrical and electronic equipment parts such as tape recorders, videos, stereos, and computer parts, and automobile parts such as wind louvers, door handles, and fuel lids. be able to. Furthermore, performance can be improved by using it as a base for high-order processed products, such as painted products and resin-plated products.

In particular, when the composition of the present invention is used as a resin-plated product, it has the advantage that in addition to the excellent effects of the composition of the present invention itself, a resin-plated product with extremely excellent plating film adhesion can be obtained.

When plating a molded article obtained by molding the composition of the present invention, first perform preliminary treatment such as wiping off an oil film on the surface of the molded article as necessary, and then roughen the surface using an alkaline solution. It is preferable.

As the alkaline solution used for surface roughening treatment, alkaline components such as potassium hydroxide, sodium hydroxide, and magnesium hydroxide are dissolved in a solvent such as water, phenols, alcohols, etc., or in a mixed solvent thereof at a temperature of 5 to 50,511 degrees. Aqueous solutions of sodium hydroxide and potassium hydroxide are particularly preferably used.

The conditions for this surface roughening treatment (alkali etching) are 30~
It is desirable to immerse the molded article in an alkaline solution at 95° C. for 1 to 120 minutes, and then thoroughly wash it.

After the alkali etching treatment is completed, the molded article may be sufficiently washed with water, and then further surface treated with an acidic aqueous solution having a pH of 3 or less. In this case, the acid component used is a mineral acid such as sulfuric acid or hydrochloric acid, and the appropriate treatment conditions are 5 to 70°C for 2 to 60 minutes.

By subsequently subjecting the surface-roughened resin molded article for plating to a conventional plating treatment, it is possible to obtain a resin-plated article with extremely excellent plating film adhesion and good surface photovolatility.

The plating process may also include, for example, sensitizing with a stannous chloride solution, activating with a palladium chloride solution, electroless copper or nickel plating, electroplating steps, or electroplating, accelerating, and electroless Metsky electroplating. A normal chemical plating method consisting of steps can be applied.

The excellent properties of the resin-plated product of the present invention are due to the formation of holes that have an effective anchoring effect for plating with aluminum oxide particles, - especially 0.5~
Aluminum oxide with an average diameter of 10 μm is preferred. In contrast, other fillers such as calcium carbonate, gypsum,
mica, clay, silica, calcium silicate, talc,
Calcium metasilicate etc. cannot improve plating performance due to its unsuitable powder form.<Examples> The effects of the present invention will be further explained below with reference to Examples.

In addition, each abbreviation in an Example means the following.

PBT: Polybutylene terephthalate PBT/A:
/butylene (terephthalate/adipate) (terephthalic acid component/adipic acid component copolymerization molar ratio = 80/2
0) PBT/S: Polybutylene (terephthalate/sebacate) (terephthalic acid component/sebacic acid component copolymerization molar ratio = 80/20) PBT/D-1: Polybutylene (terephthalate/decane dicarboxylate) (terephthalic acid component/decane Dicarboxylic acid component copolymerization molar ratio = 80/20) PBT/D-2: Polybutylene (terephthalate/decanedicarboxylate) (same as above Copolymerization molar ratio = 60/
40) E/GMA Niethylene/glycidyl methacrylate copolymer (copolymerization weight ratio = 90/10) E/GMA/V
A: Ethylene/glycidyl methacrylate/vinyl acetate copolymer (copolymerization weight ratio = 82/12/6) PBT-PTMG: Polybutylene terephthalate/poly(tetramethylene oxide) glycol flock copolymer (soft segment/hard segment weight ratio” 4
0/60) PBT/I-PTMG: Polybutylene (terephthalate/isophthalate)/polytetramethylene oxide glycol block copolymer (terephthalic acid component/isophthalic acid component copolymerization molar ratio = 70/30
, soft segment/hard segment weight ratio=20/
80) Examples 1 to 10 Polybutylene terephthalate (PB) with a relative viscosity of 1.57
T) 100! Tri-blend aluminum oxide having the average particle diameter I shown in Table 1 to i part in the proportion shown in Table 1, and melt-mix this using an extruder equipped with a 40Hφ screw set at 250°C. Pelleted.

Next, the obtained pellets were placed in an injection molding machine set at 250°C, and the mold temperature was 80°C.
Thick disk molded product (impact test piece with test piece A (test piece B)
) was molded.

For molding warp, test specimen A is used as a test sample, test sample 1 is placed on reference surface 2 as shown in Fig. 1, a point 3 on the circumference is fixed to reference surface 2 with fixture 5, and the diameter is The clearance of another point 4 on the circumference in the direction from the reference surface 2 was measured, and the ratio of the clearance to the diameter of the clearance (8) expressed in % was evaluated as the amount of molding warpage. (The effective amount of molding warpage is 0.5% or less.) Impact resistance was evaluated by measuring the Izot impact strength of test piece B.

The smoothness of the molded product was determined by measuring the surface roughness of test piece A using a surface roughness meter manufactured by Tokyo Seimitsu Co., Ltd. The surface smoothness was expressed and evaluated using the difference (Rmax) between the highest and lowest portions of the surface irregularities that were actually measured. (Effective surface smoothness is Rmax 2.
(0 μm or less) These evaluation results are shown in Table 1.

Comparative Examples 1 to 9 Polybutylene terephthalate (PBT) with relative viscosity L57
) 100 parts by weight of the various fillers shown in Table 1 were triblended in the proportions shown in Table 1, and this was pelletized in the same manner as in Example 1. Performance was subsequently evaluated in the same manner as in Example 1.

The results are shown in Table 1.

Examples 11-25 Polybutylene terephthalate (PBT) with relative viscosity L57
) and the aliphatic dicarboxylic acid copolyester shown in Table 2 are tri-blended in the proportions shown in Table 2, and aluminum oxide having the average particle size (d) shown in Table 2 is tri-blended. After tri-blending in the proportions shown in the table, this was melt-mixed under the same conditions as in Example 1 and pelletized.

Subsequently, the amount of molding warpage, impact resistance, and surface smoothness were measured and evaluated in the same manner as in Example 1.

These results are shown in Table 2.

Examples 26-37 Polybutylene terephthalate (PBT) with relative viscosity L57
) and the glycidyl group-containing olefin copolymer shown in Table 3 are triblended in the proportions shown in Table 3, and then aluminum oxide having the average particle size (d) shown in Table 3 is triblended. After tri-blending at the ratio shown in , this was melt-mixed under the same conditions as in Example 1 and pelletized.

Subsequently, molding warpage, impact resistance, and surface smoothness were measured and evaluated in the same manner as in Example 1.

These results are shown in Table 3.

Examples 38-49 Polybutylene terephthalate (PB) with relative viscosity L57
T) and the polyester elastomer shown in Table 4.
Dry plain to the proportions shown in the table, and then
Aluminum oxide having the average grain size shown in the table was
After tri-blending in the proportions shown in the table, this was melt-mixed and pelletized under the same conditions as in Example 1. Continuing,
The amount of molding warpage and impact resistance 11 surface smoothness were measured and evaluated using the same method as in Example fIJ1.

These results are shown in Table 4.

As is clear from the results in Tables 1 to 4, the polyester composition of the present invention has balanced molding warpage prevention, impact resistance, and surface smoothness compared to the conventional filler-reinforced polyester composition. It's excellent.

Example 50 The composition of Example 2 was injection molded to produce a disc molded product with a thickness of 125 fiφ x 2 m. After roughening the surface by immersing the molded product in a 40% sodium hydroxide solution at 8υ℃ for 10 minutes, resin plating was applied using a conventional resin plating method, and the adhesion of the plating film to the resin was measured. did. In addition, polybutylene terephthalate, which does not contain granular aluminum oxide, was plated in the same way and the adhesive strength was measured.
The L 3 &p /lx for the composition of the present invention was 0.14/ff or less for polybutylene terephthalate.

It can be seen that the composition of the present invention is excellent as a base for resin plating.

<Effects of the Invention> The polyester composition of the present invention provides a molded article with small mold warpage, excellent mechanical properties, and excellent surface appearance with good smoothness.

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams showing an apparatus for measuring the amount of molding warpage in an embodiment, with FIG. 1 being a plan view and FIG. 2 being a surface measurement view. l: Test sample 2: Reference surface 5: Fixture 4: Clearance

Claims (6)

[Claims] (1) A polyester resin composition comprising 5 to 250 parts by weight of granular aluminum oxide mixed with 100 parts by weight of thermoplastic polyester. (2) The polyester resin composition according to claim 1, wherein the aluminum oxide has an average particle size in the range of 0.5 to 10 μm. (3) The polyester resin composition according to claim 1, wherein the thermoplastic polyester contains 3 to 50% by weight of aliphatic dicarboxylic acid copolymerized polyester. (4) The polyester resin composition according to claim 1, wherein the thermoplastic polyester contains 0.5 to 40% by weight of a glycidyl group-containing olefin copolymer. (5) The polyester resin composition according to claim 1, wherein the thermoplastic polyester contains 3 to 50% by weight of polyester elastomer. (6) The polyester resin composition according to claim 1, wherein the composition is a plating composition.