JPS60184549A - Polybutylene terephthalate resin composition for plating - Google Patents

Abstract

PURPOSE:To obtain a resin compsn. which has excellent adhesion to plate film and thermal cycle properties and gives good surface appearance, by incorporating titanium dioxide in a copolyester resin composed of a dicarboxylic acid component and a diol component. CONSTITUTION:10-250pts.wt. titanium dioxide having an average particle size of 1-6mu is incorporated in 100pts.wt. copolyester resin composed of a dicarboxylic acid component (a) contg. at least 60mol% of terephthalic acid and 0.2- 18mol% of metal sulfoisophthalate component and/or metal sulfoisophthalate component and a diol component (b) mainly composed of 1,4-butanediol. When the average particle size is smaller than 1mu, plated articles whose plated film has a low bond strength and which has poor thermal cycle properties are formed, while when the average particle size exceeds 6mu, the brightness of plating is greatly lowered and commercial value as a plated article is remarkably reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polybutylene terephthalate resin composition for plating, which provides an excellent metal coating upon plating. For more details, please refer to the excellent adhesion of plating film,
The present invention relates to a polybutylene terephthalate resin composition for plating that provides thermal cyclability and good surface appearance at the same time.

Generally, the plating treatment of plastics is (1) pretreatment, cl
This is done by sequentially repeating the following steps: roughening treatment (Esotinog), (3) sensitization treatment (Sentailing), (4) activation treatment (Activationog), (5) electroless plating, and (6) electroplating. The steps from step (3) above are usually called the plating step.

Among these, the surface roughening treatment (2) above is an important process that affects the adhesion of the metal plating film provided in the subsequent plating process, and various methods are used depending on the type of plastic. .

In plating thermoplastic polyester resin, for example, there is a method of roughening the surface of polyester resin containing a filler in advance (Japanese Unexamined Patent Publication No. 1'5977).
However, even if these are applied to polybutylene terephthalate resin, which has poor crystallization properties, it is not possible to satisfy both excellent plating film adhesion and a good surface appearance, and it is difficult to use them practically. It is not possible to obtain excellent polybutylene terephthalate plated products.

Therefore, the present inventors conducted research with the aim of obtaining a polybutylene terephthalate resin-plated product that has excellent plating film adhesion and surface appearance at the same time. Excellent polybutylene terephthalate plating is achieved by roughening a molded product made of a titanium dioxide compound with an average particle size in a very limited range of 1 to 6 μm using an alkaline solution, and then subjecting it to a conventional plating process. It was discovered earlier that the product could be obtained.

However, although this method significantly improves the average value of the adhesion strength of the plating film, there are large variations in the adhesion strength of the plating film locally, and there are places where the adhesion strength is extremely low depending on the area. It has been found that this causes blistering and peeling of the plating, which is a problem that is not practical.

These drawbacks are due to the poor affinity between the titanium dioxide contained in the polybutylene terephthalate resin and the titanium dioxide, which leaves molding distortion in various parts of the molded product due to the resin flowing in the mold during molding. This is thought to be due to the fact that titanium is not uniformly dispersed and a homogeneous rough surface cannot be obtained by etching.

At Sonin, the present inventors have developed a polybutylene terephthalate for plating that has no variation in plating film adhesion strength, has uniform plating film adhesion strength and thermal cyclability, and provides an excellent plating appearance at the same time. As a result of further studies to obtain a resin composition, it was discovered that the above object can be effectively achieved by a composition using polybutylene terephthalate as a base polymer, which is copolymerized with a component containing a metal sulfo compound.The present invention has been made. reached.

That is, the present invention provides (c) (a) a dicarboxylic acid component in which 60 mol% or more is a terephthalic acid component and 0.2 to 18 mol% is a metal/sulfoisophthalic acid component and/or a metal sulfoterephthalic acid component; Φ) For 100 parts by weight of copolyester resin consisting of a diol component mainly composed of 1,4-butanediol, 10 to 25 parts of chikuno dioxide with an average particle size of 1 to 6 μm
The object of the present invention is to provide a polybutylene terephthalate resin composition for plating containing 0 parts by weight.

The polyester resin used in the present invention includes (a) 60 mol% or more of a terephthalic acid component, and 0.2 to 18 mol%
It is a copolymer obtained by condensation polymerization of a dicarboxylic acid component which is a metal sulfoisophthalic acid component and/or a metal sulfoterephthalic acid component and (b) a diol component whose main component is 1,4-butanodiol.

The terephthalic acid component mentioned here includes terephthalic acid and its ester-forming derivatives, and the content of the terephthalic acid component is preferably 60 mol% or more, particularly 70 mol% or more. If it is less than 60 mol%, the heat resistance will deteriorate, which is not preferable.

The metal sulfinophthalic acid component and the metal sulfoterephthalic acid component are expressed by the following general formula (where M is lithium, sodium, potassium, magnesium, calcium, strontium, barium, or zinc. R' and R' are Hydrogen, methyl, ethyl, phenyl, 2-hydroxyethyl, 4-hydroxybutyl), and specifically, for example,
Examples include 5-sodium sulfoisophthalate, dimethyl 5-sodium sulfoisophthalate, 5-magnesium sulfoisophthalate, dimethyl 5-magnesium sulfoisophthalate, 4-sodium sulfoisophthalate, 2-sodium sulfoterephthalate, etc. -Sodium sulfoisophthalic acid or 5-sodium sulfo l-1-J+1+ &o;Z j E, +, Ko ζJ
im, 4 Jr. The copolymerization amount of the metal sulfoisophthalic acid and/or metal sulfoterephthalic acid component is preferably 0.2 to 18 mol%, particularly 0.5 to 10 mol%. At 0.2 mol% US, the effect of improving the variation in adhesion of the plating film is small, and the thermal cyclability is poor.
If it exceeds mol%, the crystallization performance deteriorates and the molding processability of the resin becomes extremely poor, which is not preferable.

Other recarboxylic acid components used with these recarboxylic acid components include isophthalic acid, orthophthalic acid, 2,6-naphthalylcarboxylic acid, I+5-naphthalene dicarboxylic acid, bis(p-carboxyphenyl)methane, and anothracercarboxylic acid. Aromatic dicarboxylic acids such as hon 2-bis(phenoxy)ethano-4,4'-; carboxylic acid, alicyclic growing carboxylic acids such as 1,3-chlorohexanodicarboxylic acid, and 1,4-nochlorohexanedicarboxylic acid , adipinoic acid, sebacic acid, azelaic acid, decaneleonic acid, dodecanedioic acid, hexadecanedioic acid, octadodecanedioic acid, dimer acid, and other aliphatic dicarboxylic acids and ester-forming derivatives thereof. The amount of copolymerization of the dicarboxylic acid is suitably 35 mol% or less.

In addition, as a diol component, the main component 1. In addition to 4-butanediol, aliphatic glycols having 2 to 2 carbon atoms, namely 1, ethylene glycol, propylene glycol, neopenotyl glycol, 1,5-pentanodiol, 1,6-hexalol, decamethylene glycol, etc. glycol,
Noclohexalmethanol, noclohexanediol, etc., or long chain glycols with molecules ffi 400-6, O O O, i.e. polyethylene glycol, poly-1. 3-propylene glycol, polytetramethylene glycol, etc. can be copolymerized in a small proportion, especially 30 mol% or less. Preferred specific examples of these copolymerized polyester resins include polybutylene terephthalate,
Examples include 5-sodium sulfoisocrate, polybutylene terephthalate/5-sodium sulfoisophthalate isophthalate, polybutylene terephthalate/5-sodium sulfoisophthalate l-φdecanedicarpoquinate, and the like. In addition, these copolymerized polyester resins are prepared by adding 0.5% 0-chlorophenol solution to 2
Those having a relative viscosity in the range of 1.2 to 2.0, particularly 1.3 to 1.85 when measured at 5°C are suitable.

Although any titanium dioxide can be used in the present invention, titanium dioxide of anatase type and rutile type produced by a sulfuric acid method or a chlorine method and having a purity of 95% or more is preferable.

The average particle diameter of titanium dioxide must be in the range of 1 to 6 μIn, and particularly preferably 2 to 45 μm. The average particle diameter herein is indicated by the maximum frequency diameter (mode diameter) determined from the particle size distribution measured by the sedimentation balance method.

If the average particle size is less than lIzm, the plated product will have poor plating film adhesion strength and thermal cyclability. If the thickness is 6 μm or more, the brightness of the plating will be significantly inhibited and the commercial value will decrease.

The amount of titanium dioxide added is 10% of the copolymerized polyester resin.
0 parts by weight, 10 to 250 parts by weight, especially 30 to 1
00 parts by weight is preferred. If the amount is less than 10 parts by weight, the effect of improving the adhesion of the plating film is insufficient. If it exceeds 250 parts by weight, the surface roughness of the molded product becomes large, and the adhesion of the plating film and the brightness of the plating are lost, which is not preferable.

When mixing the copolymerized polyester resin and titanium dioxide with an average particle size of 1 to 6 pm, other additives may be added, such as lubricants such as aluminum stearate and barium stearate, and crystal nucleating agents such as talc, clay, kaolin, and alumina. Mold release agents such as , monotano wax, and monotano acid wax metal salts, plasticizers, heat stabilizers, ultraviolet absorbers, pigments, dyes, and fibrous reinforcing agents may be added as necessary.

Other thermoplastic resins, such as polyolefin resins (polyethylene, ethylene-vinyl acetate copolymer, ethylene-propylene-f-maleic anhydride copolymer, ethylene-butene-1-y-maleic anhydride copolymer) may also be used. , ethylene-grindyl methacrylate copolymer, etc.), polyamide resin, ABS resin, polyester resin other than the present invention (polybutylene terephthalate O isophthalate, polybutylene terephthalate sebacate, polybutylene terephthalate Φ decanodicarpoquinate) , polybutylene terephthalate 1-, arepe I-, etc.), polyester amide resins, polyether ester block copolymers, etc. may be added as necessary. The copolymerized polyester resin, titanium dioxide having an average particle size of 1 to 6 μm, and other additives may be blended by any means, such as simultaneous mixing using a screw extruder or the like.

Polyphthalene terephthalate 1-61 resin M for plating A molded product for plating can be easily obtained by arbitrarily adopting a normal thermoplastic resin molding method such as injection molding, extrusion molding, or flow molding. I can do it.

When plating a molded article for plating made of the polybutyrenoterephthalate resin composition for plating of the present invention, first, if necessary, a preliminary treatment such as wiping off an oil film on the surface of the molded article is performed, and then roughening is performed using an alkaline solution. It is important to bring this to the surface. The alkaline solution used for surface roughening treatment is an alkali component such as potassium hydroxide, sodium hydroxide, magnesium hydroxide, etc., mixed with a solvent such as water, phenols, alcohols, etc., or a mixed solvent thereof.
% concentration, and among them, aqueous solutions of sodium hydroxide and potassium hydroxide are preferably used.

The conditions for this roughening treatment (alkaline esotinog) 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 completing the alkaline etch knob and thoroughly cleaning the molded product,
Furthermore, surface treatment may be performed 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 subjecting the polybutyrenoterephthalate resin molded product that has been roughened in this way to a conventional plating process, the plated film has extremely good adhesion strength and thermal cyclability, and the plated product has good mechanical properties. Resin plated products can be obtained.

Plating treatments include, for example, tin chloride solution, activation with balanium chloride solution, electroless copper or nickel plating, electroplating steps, or catalytic acceleration, electroless electroplating. A normal plating method consisting of each step can be applied.

The surface metallized polybutylene terephthalate 1/resin molded product of the present invention has excellent heat resistance, mechanical properties, thermal cycling properties, plating film adhesion, and surface brightness, so it can be used in various automobile parts, electrical parts, and Useful as mechanical parts.

The effects of the present invention will be further explained below with reference to Examples.

Examples 1 to 13, Comparative Examples 1 to 5 Terephthalic acid, inophthalic acid, dotecanedionoic acid, and the metal sulfo compounds shown in Table 1 were used as acid components, and 1,4
- 100 parts by weight of a copolymerized polyester resin prepared by copolymerizing butanediol as a diol component in the proportions shown in Table 1, and titanium dioxide having an average particle size B'Itm as shown in Table 1, triblended at a ratio of 75. , melt-kneaded using a screw extruder set at 250°C, and
It's changed.

Next, the obtained belene I~ was subjected to an injection molding machine set at 250°C, and a width of 50us was molded at a mold temperature of 80°C.
x Length 80IllIl x Height 35 fins x Thickness 2.5 mW
A box-shaped molded product (molded product for plating) was molded.

Next, the molded product was placed in a 30% sodium hydroxide aqueous solution at 70°C.
for 5 minutes, and then soaked in 2% hydrochloric acid aqueous solution at 30°C for 10 minutes.
The molded product was immersed for a second and then rinsed thoroughly in running water to obtain a molded product with a roughened surface.

This molded article with a roughened surface was subjected to plating treatment by the method shown below.

(1) Catalyst: The molded product with a roughened surface was immersed in Catalyst liquid (trade name A-30 Catalyst Okuno Pharmaceutical Co., Ltd.) for 3 minutes at 30°C.

(2) Washing with water.

(3) Accelerator: Immersed in a 10% H2SO aqueous solution at 40°C for 5 minutes.

(4) Wash with water.

(s) ltg Kt Decomposed nickel plated molded product subjected to electroless plating by immersing it in an electrolytic nickel plating solution (product name: TMP chemical nickel plating solution Okuno Pharmaceutical Co., Ltd.) at 40°C for 8 minutes. Obtained.

(6) Wash with water.

(7) Electroplating (bright copper plating): Electroless plated molded product with 50g of concentrated sulfuric acid and copper sulfate (pentahydrate)
2QOg, SCB-MUlocc as brightener, 5CB
-11cc (manufactured by Okumachi Pharmaceutical Co., Ltd.) and water 1.
Placed in an acidic copper plating bath consisting of OOOcc at a temperature of 25
Electroplating was performed under conditions of ~30'C1 current density 4A/d,,, = to form a copper plating film with a thickness of about 30μ (plating test specimen A).

(8) Wash with water.

(9) Electroplating (bright Ninocal Mesoki): The molded product after plating with bright copper was coated with 40 g of boric acid, nickel chloride hexahydrate 50F, nickel sulfate heptahydrate 300 g, and Monolyl-I OC as a brightener. , ActB-120CC (
A nickel plating film with a thickness of 15 μm was formed by electroplating at a temperature of 50°C and a current density of 5 A/dm' in a nickel plating bath consisting of Okuno Pharmaceutical Co., Ltd. product) and 1.000 Cr of water. .

Shout, wash with water.

Ql) N, air plating (chromium plating) After ltg/bright nickel plating, molded product is coated with 5g of sulfuric acid and 250g of chromium oxide.
A chromium plating film with a thickness of 025μ was formed by electroplating in a chromium plating bath consisting of g and water L OOOcc at a temperature of 50°C and a current density of 40A/dm' (plating test specimen B). .

Plating test specimens A and B were obtained using the above method.

Plating test specimen A was used to measure the adhesion of the plating film and its variation. The adhesion strength of the plating film was measured at four locations in the test piece, and the variation was evaluated based on the difference between the maximum value and the minimum value. In addition, the adhesion strength of the plating film is 10 mu url]
2 Q my 7. This was done by measuring the strength of T-peeling in a direction of 90° at a speed of 1/min.

Thermal cycle test was conducted using plating dest test piece B.
0° C. (lhr) −*150Y: (lhr) (Exposure to the D atmosphere was considered as one cycle, and after four consecutive cycles were performed, the presence or absence of abnormalities on the plating surface was evaluated by visual inspection.

As is clear from the results in Table 1, the plated polybutylene terephthalate resin molded product made of the composition of the present invention is a polybutylene terephthalate-1-based product that does not have a sulfometal salt-containing inophthalic acid component. Compared to resin plated products,
It is observed that the adhesion of the plating film is good, the variation in the adhesion of the plating film depending on the part is small and uniform, and the thermal cycleability is excellent.

Claims (1)

[Scope of Claims] (f) (a) A dicarboxylic acid component in which 60 mol% or more is a terephucric acid component and 0.2 to 18 mol% is a metal sulfoiophthalic acid component and/or a metal sulfoterephthalic acid component. (1)) 10 to 250 parts of titanium dioxide with an average particle size of 1 to 6 μm per 100 parts by weight of a copolyester resin consisting of a leol component whose main component is 1.4-phthanediol.
A polyphthalene terephthalate resin composition for plating containing parts by weight.