JPH0325511B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for metallizing the surface of a thermoplastic polyester resin molded article by plating. More specifically, the present invention relates to a method for manufacturing a surface-metallized polyester resin molded product that has excellent plating film adhesion and a good surface appearance. Aromatic polyester resins, represented by polyethylene terephthalate and polybutylene terephthalate, have excellent mechanical properties, heat resistance, and chemical resistance, so they are used in a variety of applications such as electrical parts, automobile parts, and mechanical parts. There is. Furthermore, these metal-plated products that give a metallic appearance to aromatic polyester resin molded products retain the characteristics of the aromatic polyester resin itself, so they offer superior performance that conventional ABS resin or polypropylene metal-plated products do not have. It is expected that the application will expand to new fields. Generally, plastic plating treatment involves (1) pretreatment;
(2) Surface roughening treatment (etching), (3) Sensitizing treatment (4) Activation treatment (actipating), (5) Electroless plating and (6) Electroplating processes. The process from step (3) above is usually called the plating process. Among these, the surface roughening treatment (2) above is an important process that affects the adhesion of the metal plating film applied in the subsequent plating process, and various means are used depending on the type of plastic. For example, ABS For resins, a chemical etching method has been established in which molded products are immersed in a chromic acid-sulfuric acid mixture. As a means for roughening the surface when plating thermoplastic polyester resin, methods include immersing the molded product in an alkaline hydroxide solution (Japanese Patent Application Laid-Open No. 1983-6874), and immersing the molded product in a phenol solution and then further immersing it in an aqueous alkaline solution. Method (Japanese Unexamined Patent Publication No. 1983-6875)
and a method of treating molded products with a mixed solution of alcohol, alkali, and water (Japanese Patent Application Laid-open No. 1983-68877)
However, these methods cannot sufficiently erode the surface of the molded product and require the polyester resin to contain a filler such as glass fiber or calcium carbonate in advance, but the desired surface roughness can still be achieved. As a result, the adhesion of the plating film on the plated product is poor, making it impossible to obtain a practically excellent surface-metallized polyester resin molded product. Therefore, the present inventors studied the surface metallization of aromatic polyester resin by metal plating with the aim of further improving the adhesion of the plating film, and found that a combination of aromatic polyester resin and a small proportion of aliphatic polyester resin The excellent properties of the aromatic polyester resin itself are maintained by roughening the molded product using an alkaline solution and then applying a regular plating process.
It has been found that a surface-metallized polyester resin molded article with excellent plating film adhesion and a good surface appearance can be obtained. That is, the present invention uses aromatic polyester resin 100
After roughening the surface of a polyester resin molded product containing 1 to 90 parts by weight of aliphatic polyester resin using an alkaline solution,
The present invention provides a method for producing a surface-metallized polyester resin molded product, which is characterized by plating treatment. The aromatic polyester resin used in the present invention is
A polymer or copolymer whose main components are a dicarboxylic acid component of which 60 mol% or more is an aromatic dicarboxylic acid and a diol component. The aromatic dicarboxylic acids mentioned here include terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, bis-benzoic acid, bis(p-carboxyphenyl)methane, anthracene Examples include dicarboxylic acid, 4,4'-diphenyldicarboxylic acid, and ester-forming derivatives thereof. The dicarboxylic acid component is 40 mol% or less of aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, and dodecanedioic acid, and alicyclic acids such as 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid. At least one dicarboxylic acid and an ester-forming derivative thereof may be contained as a copolymerization component. In addition, diol components include aliphatic glycols having 2 to 20 carbon atoms, such as ethylene glycol, propylene glycol,
1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, decamethylene glycol, cyclohexanedimethanol, cyclohexanediol, etc., or long chain glycols with a molecular weight of 400 to 6000,
i.e. polyethylene glycol, poly-1,3
- Propylene glycol, polytetramethylene glycol, etc., and ester-forming derivatives thereof are mentioned, and two or more types of these can be used in combination. Specific examples of these aromatic polyester resins include polyethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polypropylene terephthalate, polybutylene terephthalate, polybutylene terephthalate isophthalate, polybutylene terephthalate sebacate, polyheximethylene terephthalate, and Examples include cyclohexane dimethylene terephthalate and mixtures thereof, and among these, polybutylene terephthalate and polyethylene terephthalate, which have good mechanical properties, are particularly preferably used. Also, these aromatic polyester resins contain 0.5%
The relative viscosity of the o-chlorophenol solution measured at 25° C. is preferably in the range of 1.2 to 2.0, particularly 1.3 to 1.85. The aliphatic polyester resin used in the present invention is
(a) polylactone obtained by ring-opening polymerization of lactone, (b) polyester-polylactone block copolymer obtained by reaction of polyester oligomer and lactone, (c) polycondensation reaction of dicarboxylic acid component, diol component, and lactone. It is at least one selected from the obtained copolymerized polyester and (d) fully aliphatic polyester whose main components are an aliphatic dicarboxylic acid and a diol component. Here, (a) polylactone has the general formula [-O(-CR ₁ R ₂ ) _-n-
CO〕 _−o (R ₁ and R ₂ in the formula are hydrogen, methyl group,
ethyl group, m is an integer from 2 to 5, n is an integer from 5 to 1500)
Specific examples thereof include poly(β-propionlactone), poly(γ-butyrolactone), and poly(ε-caprolactone). (b) Polyester-polylactone block copolymer is a prepolymer obtained by reacting a polycondensed oligomer produced from a dicarboxylic acid and diol with hydroxyl groups at both ends with a lactone in the presence of a bifunctional acylating agent. It is a polymer obtained by a method such as oxidation, and specifically, polyethylene adipate-poly-ε-caprolactone block copolymer, polyethylene sebacate-
poly-ε-caprolactone block copolymer,
Polyethylene azelate-poly-ε-caprolactone block copolymer, polybutylene terephthalate-poly-ε-caprolactone block copolymer, polyethylene terephthalate-poly-ε-caprolactone block copolymer, and polybutylene terephthalate-isophthalate-poly- Examples include ε-caprolactone block copolymer. (c) Copolymerized polyester specifically refers to poly-ε
- caprolactone butylene terephthalate,
Examples include poly-ε-caprolactone butylene sebacate terephthalate. Note that in (b) and (c) above, when the aromatic dicarboxylic acid accounts for 50 mol % or more of the dicarboxylic acid component, it is necessary that 50 mol % or more of the entire dicarboxylic acid component consists of a lactone compound. (d) Fully aliphatic polyester is a polymer or copolymer whose main components are a dicarboxylic acid component and a diol component in which 50 mol% or more is an aliphatic dicarboxylic acid. Examples include azelaic acid, sebacic acid, decanedionic acid, octadodecanedioic acid, and ester-forming derivatives thereof. Note that the dicarboxylic acid component may contain aromatic dicarboxylic acids, alicyclic dicarboxylic acids, ester-forming derivatives thereof, and the like as copolymerization components within a range of less than 50 mol %.
Note that specific examples of the aromatic dicarboxylic acid, the alicyclic dicarboxylic acid, and the diol component are the same as those for the aromatic polyester resin, so a description thereof will be omitted. Specific examples of (d) fully aliphatic polyesters include polyethylene adipate, polybutylene terephthalate sebacate, polybutylene terephthalate decanedicarboxylate, polyethylene terephthalate adipate, and polyethylene terephthalate sebacate. . Among these aliphatic polyester resins, poly(ε-caprolactone), polybutyreterephthalate-poly(ε-caprolactone) block copolymer, polybutylene terephthalate sebacate, and polyterephthalate decanedicarboxylate are particularly preferably used. be done. The amount of aliphatic polyester resin added is 1 to 90 parts by weight per 100 parts by weight of aromatic polyester resin.
Particularly preferred is 3 to 60 parts by weight; if it is less than 1 part by weight, the effect of improving the adhesion of the plating film is insufficient;
If the amount exceeds 1 part by weight, the mechanical properties and heat resistance of the aromatic polyester resin itself will deteriorate, which is not preferable. When mixing aromatic polyester resin and aliphatic polyester resin, titanium oxide, zinc oxide,
Magnesium oxide, silicon oxide, potassium titanate, magnesium carbonate, calcium carbonate, calcium/magnesium carbonate, calcium metasilicate, barium sulfate, talc, kaolin, clay,
It is possible to add fillers such as silica, mica, asbestos, thyroid, alumina, glass balloons, and shirasu balloons, and by doing so, it is possible to expect even better adhesion strength of the plating film. However, the amount of these fillers added is preferably in the range of 3 to 300 parts by weight, particularly 5 to 200 parts by weight, per 100 parts by weight of the aromatic polyester resin. Other usual additives such as lubricants, mold release agents, nucleating agents, plasticizers, flame retardants, heat stabilizers, UV absorbers, pigments, dyes, fibrous reinforcements and other thermoplastics are also required. It can also be added depending on the situation. The aromatic polyester resin, the aliphatic polyester resin, and other additives may be blended in any way, for example, a method of simultaneously mixing them using a screw extruder or the like can be adopted. For the production of polyester resin molded products from the compound, any ordinary thermoplastic resin molding methods such as injection molding, extrusion molding, and blow molding can be used, and polyester resin molded products for plating in the desired shape can be easily obtained. Can be done. When plating according to the method of the present invention, it is important to first perform preliminary treatment such as wiping off the oil film on the surface of the molded article as necessary, and then roughen the surface using an alkaline solution. The alkaline solution used for surface roughening treatment is a solution in which alkaline components such as potassium hydroxide, sodium hydroxide, and magnesium hydroxide are dissolved in a solvent such as water, phenols, alcohols, or a mixed solvent thereof to a concentration of 5 to 50%. Solutions, among which aqueous solutions of sodium hydroxide and potassium hydroxide are preferably used. The conditions for this surface roughening treatment (alkali etching) are preferably that the molded product is immersed in an alkaline solution at 30 to 95°C for 1 to 120 minutes, and then thoroughly washed. Even if a molded product made of aromatic polyester resin alone is subjected to this alkali etching, the degree of surface erosion is small and sufficient surface roughness cannot be achieved, but aromatic polyester resin molded products containing a small proportion of aliphatic polyester resin If the product is subjected to a similar alkaline etching treatment, a rough surface is obtained which is highly suitable for plating. This effect of the present invention is probably due to the selective decomposition of the aliphatic polyester resin by the alkaline solution, thereby increasing the overall degree of erosion. 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 polyester resin molded product subjected to the surface roughening treatment to a conventional plating treatment, it is possible to obtain a surface-metallized polyester resin molded product with significantly excellent plating film adhesion and a good surface appearance. The plating process includes, for example, sensitizing with a stannous chloride solution, activation with a palladium chloride solution, electroless copper or nickel plating, and electroplating, or the following steps: catalyzing, accelerating, electroless plating, and electroplating. A conventional chemical plating method can be applied. The effects of the present invention will be further explained below with reference to Examples. Example 1 100 parts by weight of polybutylene terephthalate (PBT) with a relative viscosity of 1.575 was blended with the aliphatic polyester resin and other additives shown in Table 1 in the proportions shown in Table 1, and a screw tube set at 250°C was prepared. The mixture was melt-kneaded and made into chips using an extruder. Next, this chip was subjected to an injection molding machine set at 250℃, and the mold size was 80mm x 80mm x 3mm under the condition of a mold temperature of 80℃.
A square plate test piece was molded. Similarly, 100 parts by weight of polyethylene terephthalate (PET) with a relative viscosity of 1.425 was blended with aliphatic polyester resin and other additives in the types and proportions shown in Table 1, and the mixture was extruded, melt-kneaded, and chipped.
A square plate test piece was formed by injection molding. In this case, the extruder and injection molding machine temperatures were each 280°C, and the mold temperature was 30 to 40°C. Next, each of the above test pieces was immersed in a 30% sodium hydroxide aqueous solution at 70°C for 3 minutes, and then immersed in a 2% hydrochloric acid aqueous solution at 30°C for 2 minutes, and then thoroughly washed under running water to obtain a test piece with a roughened surface. I got it. This roughened test piece was subjected to plating treatment by the method shown below. Sensitizing...The test piece is treated with stannous chloride.
30 g, immersed in a solution of 60 c.c. of hydrochloric acid (38%) and 1000 c.c. of water at 25°C for 2-5 minutes. Washing with water Activating...The test piece was washed with 0.1 g of palladium chloride, 10 c.c. of hydrochloric acid (38%), and 1000 c.c. of water.
Immerse in a solution consisting of for 1 to 3 minutes at 25℃. Washing with water Electroless copper plating...The test piece was prepared with 10 g of copper sulfate (pentahydrate), 40 c.c. of formalin (37%), 10 g of sodium hydroxide, 20 g of Rothsiel's salt, and 1000 g of water.
Chemical copper plating solution consisting of cc (PH10.0~11.5)
Soak for 10 minutes at 25-30℃. Washing with water Electroplating...Acidic copper plating of the test piece with 50 g of concentrated sulfuric acid, 200 g of copper sulfate (pentahydrate), 4 c.c. of brightener (UBAC ¹ product of Ebara Cordierite Co., Ltd.) and 1000 c.c. of water. It was placed in a bath and electroplated for 60 minutes at a temperature of 25 to 30°C and a current density of 4A/dm ² to form a copper plating film with a thickness of about 60μ. The plating film adhesion strength of the plated product thus obtained was measured, and the surface appearance was visually judged. The adhesion strength of the plating film is 20
This was done by measuring the force (g) when T-peeling was performed in a direction of 90° at a speed of mm/min. These results are shown in Table 1. In addition, the abbreviations of aliphatic polyester resins in Table 1 mean the following. PCL; poly(ε-caprolactone) PBT/PCL; polybutylene terephthalate-poly(ε-caprolactone)
[40:60 weight ratio] Block copolymer PBT/S; polybutylene terephthalate sebacate (T/S molar ratio = 40/60) PBT/D; polybutylene terephthalate decanedicarboxylate (T/D
Molar ratio = 40/60) PES; polyethylene sebacate

[Table] As is clear from the results in Table 1, by blending a small proportion of aliphatic polyester resin, the plating film adhesion of the aromatic polyester resin molded product is dramatically improved.

Claims (1)

[Claims] 1 For 100 parts by weight of aromatic polyester resin,
A method for producing a surface metallized polyester resin molded article, which comprises roughening the surface of a polyester resin molded article containing 1 to 90 parts by weight of an aliphatic polyester resin using an alkaline solution, and then plating the surface.