DE2453168B2 - Process for the production of a coated wire which can be soldered without detaching the coating by electrocoating with a water-dispersible paint - Google Patents

Description

(1) To achieve good solderability, the methacrylic acid ester is incorporated, which is slightly thermally is decomposed. There is no clear relationship between the thermal decomposition properties of the methacrylic acid ester and the switching temperature and scratch resistance of the coating. Thus it is important to find an optimal combination of one or more methacrylic acid esters to look for, with which balanced properties and good solderability can be achieved.

(2) Acrylonitrile is "polymerized" for resistance z. B. to increase chemical resistance.

(3) An acrylamide and / or the vinyl acetate are copolymerized to reach the switching temperature and to increase the scratch resistance.

(4) To improve the appearance of the coating and to facilitate the electrocoating process methacrylic acid is copolymerized.

Typical methacrylic acid esters are

Isobutyl methacrylate, sec-butyl methacrylate,
n-butyl methacrylate, n-propyl methacrylate,
Ethyl methacrylate, isopropyl methacrylate,
n-octyl methacrylate, n-hexyl methacrylate,
tert-butyl methacrylate, n-amyimethacrylate,
Isoamyl methacrylate, n-heptyl methacrylate and
Methyl methacrylate.

Nn-butoxymethylacrylamide is preferably used as the aeryl acid amide.

The copolymers formed have an average molecular weight of 10,000-500,000 and in particular 50,000-200,000, measured by the viscosity method in formamide.

If the methacrylic acid ester is used in a larger amount, the through-circuit temperatures are

door and the scratch resistance is reduced if, on the other hand, too little methacrylic acid ester is provided If acrylonitrile is in a larger amount is combined, so is the solderability On the other hand, when acrylonitrile is copolymerized in a smaller amount, that is Throughput temperature or breakdown temperature of the coating obtained is reduced and the chemical resistance low. If acrylamide and / or vinyl acetate are used in higher quantities are, the solderability is lowered and the appearance of the coating membrane further deteriorates the number of pinholes increases in this case. If, on the other hand, the acrylamide and / or vinyl acetate is used in smaller quantities, the switching temperature of the membrane is too low and the Scratch resistance is reduced. If methacrylic acid is used in larger quantities, it is the scratch resistance is lowered and the electrical properties are deteriorated. On the other hand, if Methacrylic acid is used in a smaller amount, so is the processability in the case of electrocoating and the appearance of the membrane is impaired

In the practice of said comonomers is water, an emulsifier and a polymerization initiator in a reaction vessel and the mixture is heated with stirring to the reaction temperature, wherein the emulsion copolymerization takes place Usually, the reaction is at 50-80 ⁰ C during 1-Loh by. A non-ionic, anionic or cationic surface-active MiUeI can be used as an emulsifier. From the standpoint of the efficiency of the coating process, it is preferred to use at least a portion of the emulsifier in the form of an anionic surfactant. Typical anionic surfactants are sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium decyl sulfate, sodium palmitate, sodium alkyl diphenyl ether disulfonate, or the like, as inorganic peroxides, organic peroxides, organic peroxides, peroxides, organic peroxides , Azo compounds or the like. Among the components of the paint, only methacrylic acid is an ionizable monomer. Accordingly, a redox catalyst is used to improve the processability of the paint in the electrocoating process and to improve the stability of the water-dispersible paint while increasing the surface charge density of the latex particles. Typical redox catalysts are potassium persulfate, sodium bisulfite or a mixture of ammonium persulfate and sodium bisulfate a conventional solder can be soldered without the coating in this area must be removed. The thickness of the coating membrane is comparable to that of conventional resin coatings. The drying conditions are also similar to the drying conditions for conventional resin coatings.

The invention is explained in more detail below with the aid of examples.

Comparative example 1

40 parts by weight of deionized water are placed in a flask and nitrogen is then passed through it in order to displace the oxygen. A mixture of 2 parts by weight of acrylonitrile, 1.5 parts by weight of vinyl acetate, 2 parts by weight of ethyl methacrylate, 3 parts by weight of methyl methacrylate and 0.5 part by weight of methacrylic acid is mixed with one part by weight of N- Methylolacrylamide mixed. This mixture is then placed in a flask and sodium lauryl sulfate is added. The mixture is heated to 60 ⁰ C and 0.015 parts by weight of potassium persulfate and 0.005 parts by weight of sodium hydrogen sulfite (dissolved in a small amount of water) are added to the mixture

ίο given. Then, the polymerization for S h at 60-70 ⁰ C under a nitrogen stream performed The N-methylolacrylamide does not dissolve in the comonomers and not in the water. Therefore, uniform emulsion copolymerization cannot be achieved.

Comparative example 2

1 part by weight of acrylamide is in a mixture of 3 parts by weight of acrylonitrile, 1 part by weight of vinyl acetate, 2 Parts by weight of n-butyl methacrylamide and 3 parts by weight of Meihyhneihaerylat dissolved, whereupon the mixture after the method according to Comparative Example 1 is copolymerized in emulsion, with a water-dispersion varnish

is formed. There are certain amounts of clots formed from the obtained A resist after Elektrotauchiackierverfahren coating membrane made Weisi a rough surface, the flexibility is good but then is carried out for 10 see at 400 ⁰ C by a soldering operation without first peel the paint. However, the switching temperature is only 205 ^° C. Therefore, the coated wire cannot be used instead of a wire coated with polyurethane. The low conversion and the low switching temperature of the film are attributed to the low reactivity of the acrylamide.

B e i s ρ i?, I 1

40 parts by weight of deionized water are placed in a flask. Then nitrogen is passed through to displace the oxygen. A mixture of 3 parts by weight of acrylonitrile, 0.7 parts by weight of vinyl acetate, 1.3 parts by weight of n-butoxyethyl acrylamide, 2 parts by weight of n-butyl methacrylate, 2.5 parts by weight of methyl methacrylate and 0, 5 parts by weight of methacrylic acid and 0.1 part by weight of sodium lauryl sulfate are added to the reaction vessel and the apparatus is heated to 60.degree. Then 0.015 part by weight of ammonium persulfate and 0.005 part by weight of sodium bisulfite, dissolved in a small amount of water, are added. The polymerization is carried out h at 75-80 ⁰ C under a nitrogen stream while. 4 The lacquer obtained is used to coat a copper wire with a diameter of 0.5 mm. The coating membrane has the following properties:

good flexibility;

good winding properties;

no pinholes or pores; Solderable at 400 ° C while it;

By switching temperature: 26O ⁰ C;

Scratch abrasion resistance (repetition): 30 times.

The properties of this coated wire allow it to be used in place of one with polyurethane coated wire.

Example 2

A mixture of 2 parts by weight of acrylonitrile, 0.5 part by weight of vinyl acetate, 1 part by weight of N-n-propoxymethylacrylamide, 3 parts by weight of isopropyl methacrylate, 3 parts by weight of methyl methacrylate and 0.5 part by weight Methacrylic acid is emulsion-copolymerized according to Example 1, a water-dispersion lacquer is produced. The lacquer obtained becomes a bare copper wire Painted with a diameter of 0.5 mm in the electrodeposition process. The coating membrane formed in the process has the following characteristics:

good windability;
no pinholes or pores;
solderable at 400 ^° C. for 5 s;
Switching temperature: 250 ° C .;
Scratch abrasion resistance (repeat): 28 times.

Thus, a wire coated with this lacquer can be used instead of a wire coated with polyurethane can be used.

Example 3

A mixture of 3 parts by weight of acrylonitrile, 0.5 parts by weight of vinyl acetate, 0.5 parts by weight of N-n-butoxymethylacrylamide, 2J> parts by weight of n-propyl methacrylate. 3 parts by weight of ethyl methacrylate and 0.5 parts by weight of methacrylic acid is emulsion-copolymerized according to Example 1, whereby a water-dispersion varnish is obtained. A bare copper wire with a diameter of 0.5 mm is coated with the lacquer obtained in an electrodeposition process. The coating membrane has the following characteristics:

good winding work,

no pinholes or pores;

solderable for 4 s at 400 ° C;

Switching temperature: 240 ⁰ C;

Scratch abrasion resistance (repeat): 25 times.

Thus, this coated wire can be used in place of a wire coated with polyurethane will.

Example 4

A mixture of 2.5 parts by weight of acrylonitrile, 0.5 parts by weight of vinyl acetate, 1.5 parts by weight of N-n-butoxyethyl acrylamide, 2 parts by weight of ethyl methacrylate, 3 parts by weight of methyl methacrylate and 0.5 parts by weight Methacrylic acid is emulsion-copolymerized according to Example 1, a water-dispersion varnish being formed will. The varnish obtained is used to create a bare copper wire with a diameter of 0.5 mm coated. The coating membrane has the following properties:

good windability;
no pinholes or pores;
solderable at 400 ^° C. for 7 s;
Switching temperature: 255 ° C;
Scratch abrasion resistance (repeat): 27 times.

Therefore, this coated wire can be used in place of a wire coated with polyurethane will.

Example 5

A mixture of 2 parts by weight of acrylonitrile, 1.5 parts by weight of vinyl acetate, 1 part by weight of N-ethoxymethylacrylamide, 2.5 parts by weight of ethyl methacrylate, 2.2 parts by weight of methyl methacrylate and 0.8 parts by weight .- 'Filing methacrylic acid is emulsion-polymerized according to Example 1, a water-dispersion varnish being formed. This lacquer is used to ^{coat a bare copper wire with a diameter of r} i of 0.5 mm.The coating membrane has the following properties:

good windability;
no pinholes or pores; solderable for 6 s at 400 ° C;
Switching temperature: 245 ° C .; Scratch abrasion resistance (repetition): 30 times.

Therefore, this coated wire can be used in place of a wire coated with polyurethane will.

Example 6

A mixture of 2 parts by weight of acrylonitrile, 4 parts by weight of methyl methacrylate; 2 parts by weight of ethyl methacrylate 1 part by weight of vinyl acetate, 1 part by weight of N-n-butoxymethylacryiamide and 1.5 parts by weight of methacrylic acid is emulsion-polymerized according to Example 1, resulting in a water-dispersion varnish. A Bare copper wire with a diameter of 0.5 mm is coated with this varnish using the electric coating process coated and the coating membrane has the following properties:

good windability;

no pinholes or pores; solderable for 5 s at 400 ° C;

Switching temperature: 250 ° C .; Scratch abrasion resistance (repetition): 28 times.

J5 Therefore, this coated wire can be used instead of a with polyurethane coated wire.

Example 7

A mixture of 3 parts by weight of acrylonitrile, 4 parts by weight of methyl methacrylate, and 2 parts by weight of ethyl methacrylate 1 part by weight of N-n-butoxymethylacrylamide and 0.5 part by weight of methacrylic acid is used according to Example 1 emulsion-polymerized, with a water-dispersion varnish is obtained. A bare copper wire with a diameter of 0.5 mm is used with this Paint is coated by the electrodeposition process and the coating membrane has the following properties:

good winding work;

no pinholes or pores; solderable at 400 ° C for 4 s; Switching temperature: 245 ° C .; Scratch abrasion resistance (repeat): 25 times.

The coated wire can sonii '. instead of one with Polyurethane coated wire can be used.

Example 8

A mixture of 3 parts by weight of acrylonitrile. 3 parts by weight of methyl methacrylate 3 parts by weight of ethyl methacrylate, 1 part by weight of vinyl acetate and 0.5 part by weight of methacrylic acid is emulsion-polymerized according to Example 1, whereby a water-dispersion varnish is formed. A bare copper wire with a diameter of 0.5 mm is coated with this lacquer using the electrodeposition process. The received

Layering membrane has the following properties:

good windability;
no pinholes or pores;
solderable for 4 s at 38O ⁰ C;
Switching temperature: 230 ° C .;
Scratch abrasion resistance (repeat): 23 times.

Therefore, this coated wire can be used in place of a polyurethane coated wire will.

Example 9

A mixture of 4 parts by weight of acrylonitrile, 4 Parts by weight of methyl methacrylate, 2 parts by weight of ethyl methacrylate, I part by weight of vinyl acetate and 0.5 part by weight of methacrylic acid is emulsion-copolymerized according to Example 1. thereby forming a water dispersion paint. With this varnish a bare copper wire is made with coated with a diameter of 0.5 mm. The coating membrane has the following properties on:

good windability;

no pinholes or pores; solderable at 380 ^° C. for 5 s; Switching temperature: 240 ⁰ C; Abrasion Resistance (Repeat): 27 times.

Therefore, this wire can be used instead of a wire coated with polyurethane.

In Examples 1 to 9, the copolymer obtained in each case was separated from the water-dispersible paint and dried and then dissolved in dimethylformamide. The average molecular weight of the respective copolymers were measured by the conventional viscosity method. It became the achieved the following results:

Average molecular weight

example 1

Example 2 Example 3 Example 4 Example 5 Example f> Example Example H Example ^l )

sthii 15th X ¹ ■ approximately i 3.5 X iii ' approximately 15th X 10 ' approximately 15th X 10 ' approximately 13th X K) ¹ approximately 15th X I0 ⁴ approximately 15th X H) ⁴ approximately 14th X K) ⁴

about 15 x IO ⁴

Claims (1)

Claim: Process for the production of a coated wire which can be soldered without detaching the coating by electrocoating with a water-dispersion paint, characterized in that an emulsion copolymer is used as the water-dispersion varnish from 35 to 65 parts by weight of one or more methacrylic acid esters, 10 to 40 parts by weight Acrylonitrile, 2 to 15 parts by weight of methacrylic acid and 3 to 30 parts by weight of vinyl acetate and / or an acrylic acid amide of the N-ethoxymethyl-, N-n-propoxymethyl-, N-n-butoxymethyl- or N-n-butoxyethyl acrylamide, based on 100 parts by weight of the copolymer, is used will. 20th The invention relates to a method for producing a solderable one without detaching the coating coated wire by electrocoating with a water-dispersion paint. Metal surfaces are provided with organic coatings in order to electrically isolate them or to protect against corrosion or mechanical damage. The coating can be electrocoated raise. In general, electrocoating leads to a high yield of the Lacquer and a reduction in the working time. In addition, this process can be easily automated And membranes without pinholes are formed. Since no organic solvents are used, there are no safety and health risks. It is generally used as a paint for electrodeposition painting a water-soluble varnish, which by dissolving a film-forming resin with a Molecular weight of several thousand with dissociable groups is produced. Such a water-soluble varnish gives good coverage even on objects with complex shapes and it will a uniform membrane is always formed. However, it has been quite difficult so far with one water-soluble varnish-to achieve a thick membrane. You could only use membranes with a thickness of received less than 20 μίτι. Because the water-soluble varnish is basically an electrolyte and the polymer molecule contains a large number of dissociable groups, a membrane formed from such a water-soluble lacquer has unfavorable electrical properties and is not particularly suitable as an electrical insulation membrane. On the other hand, water suspension paints with finely dispersed particles of a membrane-forming resin show a relatively low hiding power. Furthermore, it is difficult to form a uniform diaphragm on a complicated-shaped object. However, such varnishes also have a number of advantages. One achieves! Eich; and in a short time a thick membrane. The number of dissociated groups is small. High molecular weight polymers can be used, so that membranes having excellent mechanical properties, excellent chemical resistance and water resistance, and excellent electrical properties such as volume resistivity and breakdown voltage can be obtained. To date, wire coated with polyurethane has been used in the household appliances and communications (television and radio) fields. One of the main reasons for using a wire coated with polyurethane is that the wire can be easily soldered without first separating the coating membrane from the wire. This is a major advantage from the point of view of workability. A wire that is difficult to solder in these applications can hardly be used. From US-PS 29 94 676 a coating composition made of acrylonitrile, acrylamide and alkyl acrylate is known However, this is unsuitable for electrodeposition coating of wire It is therefore an object of the present invention to provide a Process for the production of a coated coating which can be soldered without prior detachment of the coating To create wire by electrocoating with a water-dispersible paint, which becomes a Coating with good mechanical and electrical properties leads According to the invention, this object is achieved in that an emulsion copolymer is used as the water-dispersion varnish from 35 to 65 parts by weight of one or more methacrylic acid esters, 10 to 40 parts by weight Acrylonitrile, 2 to 15 parts by weight methacrylic acid and 3 to 30 parts by weight vinyl acetate and / or one Acrylic acid amides of the N-ethoxymethyl-, N-n-propoxymethyl-, N-n-butoxyethyl-acrylamide, based on 100 parts by weight of the copolymer, is used. The paint used has the following main advantages: