RU2421491C2 - Enamel for colour code marking of electronic technology - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: enamel includes semi-finished product of enamel that represents pigment suspension in a mixture of synthetic resins, acid catalyst silicone lacquer KO-945 organic high-temperature solvent propylene carbonate. Enamel for colour marking of radio parts provides marking of high quality, eliminates such defects as colour strip unevenness by width, strip duality and missing colour, filiform gaps, drying cracks and ragged edges of the strip, insufficient brightness, fusion of two strips.

EFFECT: improvement of radio parts marking quality results in increase of serviceable products output.

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Description

The invention relates to the field of electronics and can be used mainly for color ring marking in the manufacture of non-wire cylindrical resistors.

Marking paints consisting of natural and synthetic film-forming agents, pigments, fillers and organic solvents are known. However, these paints do not have sufficient adhesion of the marks to the surface of the parts and resistance to organic solvents.

In order to increase the adhesion and resistance to organic solvents, the composition of the marking paint [1], consisting of natural and synthetic film-forming agents, pigments, fillers and organic solvents, introduced diglycidyl ether of hydroquinone in an amount of 1-5 parts by weight and methyltetrahydrophthalic anhydride in an amount of 2-10 parts by weight per 100 parts by weight paints.

However, this marking paint cannot be used for color ring marking, in particular, in the manufacture of non-wire cylindrical resistors for the following reasons:

- the paints do not contain a set of pigments that would allow, in combination with film-forming, to obtain the color gamut necessary for applying the coded marking of cylindrical resistors in the form of color strips (12 colors);

- method of applying paints - offset printing assumes a limited time ability to apply markings due to their drying on the intermediate rollers and clichés, periodic updating of the ink in the marking unit, which creates additional laboriousness;

- paints do not provide the drying capacity required for the production of resistors - 1-1.5 min at a temperature of + 200 ° C.

The closest to the claimed solution for the totality of signs is the enamel ML-5265 for code marking [2] electronic products manufactured by a third party and supplied to us as components according to TU 2312-223-21743165-2002. The enamel ML-5265 is characterized by the following features: “semi-finished enamel, which is a suspension of pigments in a mixture of synthetic resins”, “acid hardener - 10% solution of sulfuric acid in butyl alcohol” and “organosilicon varnish KO-945”. Enamel is diluted with tetralin, cyclohexanone and their mixture in a ratio of 1: 1.

Enamel ML-5265 provides color ring marking, for example, on resistors made in insulated and non-insulated versions, operated in the temperature range from -60 ° C to + 155 ° C, suitable for manual and automated assembly (installation) of equipment.

A disadvantage of the known enamel for code marking, for example, resistors is the low quality of marking associated with the presence of defects such as uneven color rings, non-colored rings (hair spaces), broken rings, broken edges of the rings, insufficient brightness, which ultimately reduces the yield resistors. The percentage of defects due to poor-quality marking on the operation "Sorting of finished products" is quite large. In the process of applying color rings to a cylindrical resistor when immersing flat disks rotating around its axis in open enamel baths to transfer enamel from the disks to the resistor, rotational movement of the resistor along the transport chain of the line constructively envisages an increase in the enamel viscosity over time due to solvents such as tetralin and cyclohexanone. Therefore, during the shift, it is necessary to repeatedly reduce the viscosity of enamels by adding a mixture of these solvents directly to the “by eye” bath and each time after that adjusting the marking quality.

The objective of the invention was the creation of enamel, providing high quality color ring marking of electronic products.

The technical result of this invention is the creation of enamel of the optimal composition, guaranteeing the required marking quality.

The technical result is achieved by the fact that enamel for code marking of electronic products, including semi-finished enamel, which is a suspension of pigments in a mixture of synthetic resins, an acid hardener - 10% solution of sulfuric acid in butyl alcohol and organosilicon varnish KO-945, is characterized in that it additionally contains an organic high-temperature solvent propylene carbonate in the following quantitative ratio of components by weight:

prefabricated enamel - one hundred specified acid hardener - four organosilicon varnish KO-945 - 20-26 propylene carbonate - 5-10

Depending on the pigment component of the semi-finished product, the organosilicon varnish KO-945 is 20-26 parts by weight.

The additional introduction of propylene carbonate in the composition of marking inks allows to increase their manufacturability to obtain the required marking quality and to almost completely eliminate defectiveness. When adding carbon dioxide to a cylindrical resistor, color strips are applied, bright, uniform in width, without gaps, gaps, bifurcation, ragged edges, lack of color and fusions, which ultimately helps to increase the yield of suitable resistors.

The invention is expressed in the aggregate of essential features sufficient to achieve the technical result provided by the invention. In the claimed invention, one distinguishing feature from the prototype is a new ingredient - propylene carbonate.

Thus, in comparison with the prototype and analogue, enamel was obtained, which provides an increased quality of color ring marking of resistors. This clearly confirms the presence of a causal relationship between the totality of the essential features of the claimed invention and the achieved technical result.

As a result of the information search, no enamel was found for code marking of electronic equipment products containing all the mentioned ingredients in the indicated ratios, which allows us to conclude that it is new.

The following are specific examples confirming the possibility of obtaining the specified technical result.

To apply color ring marking on resistors, 12 mixtures (3 variants of 4 mixtures) of enamels of different colors (12 colors in each mixture) with different propylene carbonate contents were prepared (see table). In the first four mixtures (option 1), propylene carbonate was introduced directly into the enamel base (semi-finished product). The mixture was thoroughly mixed with a spatula. Subsequently, a pre-prepared mixture of varnish and acid hardener was introduced into the semi-finished product with propylene carbonate, also thoroughly mixing the components.

In the other four mixtures (second option), propylene carbonate was introduced into the mixture of varnish and acid hardener. The mixture was mixed and poured into a semi-finished enamel.

In the last 4 mixtures (third option), propylene carbonate was introduced into the mixture of all three components - semi-finished product, varnish and acid hardener. Enamels were brought to a working viscosity with a mixture of solvents - tetralin and cyclohexanone in a ratio of 1: 1.

Obtaining ring color bands from the prepared enamel options was carried out on a high-performance automated line COT - 1280-01 in the modes:

drying temperature - 195-200 ° C;

drying time - 1 min 04 sec.

The modes were set on the control panel of the line marking section. Marked resistors C2-33AI-0.125 W with a total of 14772 pcs., Of which

2535 pcs. 10.5 ohm ± 2%

(5 stripes - brown, black, green, golden, red)

3570 pcs. nominal 178 kOhm ± 2%

(5 stripes - brown, purple, gray, orange, red)

5547 pcs. nominal 249 ohm ± 1%

(4 stripes - red, yellow, white, brown)

1070 pcs. 910 kΩ ± 5%

(4 stripes - white, brown, yellow, golden)

2050 pcs. nominal value of 1,5 MOhm ± 10%

(4 stripes - brown, green, blue, silver)

Enamels of different colors prepared for work in series, depending on the required nominal value and tolerance (accuracy class) of the resistors in accordance with the color code, were placed in the marking baths, mounted on tripods in the line marking section and fixed with screws. The position of the disks, with which the strips are applied, and the plates for removing excess enamel with adjusting screws, was carried out. The rotational speed of the discs was regulated by a potentiometer on the line control panel. The adjustment was carried out to ensure the possibility of applying color strips of the required width and the required arrangement of the strips in relation to each other.

The number of applied strips, depending on the face value, is 3 or 4; to indicate the permissible deviation, 1 strip.

The acceptance mark and the key to reading are wide bands, the remaining bands are 1.5 times narrower.

The process of marking each prepared mixture of enamels was carried out on an automated line in the following sequence:

- electrical training with increased power with a measurement of the nominal value;

- application of four layers of coating material with the subsequent drying of each layer in the drying section;

- marking, which consists in applying to each colored resistor four or five color code strips with subsequent curing of the strips in the drying section.

The method of applying color strips is immersion of flat disks rotating around its axis in open enamel baths for transferring enamel from disks to a resistor during translational-rotational movement of the resistor along the line transport chain;

- electrical inspection of technological tolerances;

- packaging of resistors in adhesive tape.

Strength testing of the cured color bands was carried out by wiping them with a cloth moistened with a mixture of solvents - tetralin and cyclohexanone in a ratio of 1: 1, wiping with an alcohol-nephras mixture.

To determine the quality level of resistor labeling, a 100% visual assessment of the batch resistors was conducted according to the appearance of the marking.

The results of the assessment of labeled resistors with enamels with different content of components (in composition and percentage of components) are given in the table.

These tables show the advantage of the proposed marking material when conducting color ring marking of cylindrical resistors in comparison with the prototype, allow you to determine the optimal amount of propylene carbonate at various stages of preparation of enamels for work, namely 5-10 wt.h. regardless of the stage of introduction - in the semi-finished product, a mixture of varnish and hardener, or at the final stage in a mixture of all three components.

The increased quality of the marking enamel, which provides high technological properties, the stability of the achieved level of marking quality over time without correcting the viscosity of the mixtures during operation and during storage, indicate the possibility of using the material for marking non-wire cylindrical resistors in serial production with a significant increase in quality compared to the prototype .

The proposed marking material provides the manufacture of resistors with color ring marking, practically free of defects in the appearance of the marking, which ultimately increases the yield of suitable resistors.

In batches made on the material of the prototype, the main share of defects in appearance is poor quality marking.

Starting components in labeling material The content of the components of the marking material, parts by weight The number of the mixture (option) Prototype one 2 3 but b at g but b at g but b at g Semi-finished enamel (suspension of pigments in a mixture of synthetic resins) one hundred 100.0 Acid hardener (10% solution of sulfuric acid in butyl alcohol) 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 Organosilicon varnish KO-945 20.0 - white, yellow, orange, red; 22.0 - blue, gray, purple, golden, silver color; 24.0 - green, brown color; 26.0 - black color Propylene carbonate introduced into the semi-finished product 3,5 5,0 10.0 12.0 - - - - - - - - Propylene carbonate introduced into the mixture of varnish KO-945 and acid hardener - - - - 3,5 5,0 10.0 12.0 - - - - - Propylene carbonate introduced into the mixture of semi-finished product, varnish KO-945 and acid hardener - - - - - - - - 3,5 5,0 10.0 12.0

Literature

[1] Description of the invention to the USSR copyright certificate No. 296793, IPC C09d 3/48, publ. 04/20/1971

[2] Enamel ML-5265 of various colors, three-component marking hot drying TU 2312 - 223-21743165-2002.

Claims (1)

Enamel for color coding of electronic products, including semi-finished enamel, which is a suspension of pigments in a mixture of synthetic resins, an acid hardener - a 10% solution of sulfuric acid in butyl alcohol and organosilicon varnish KO-945, characterized in that it additionally contains organic high-temperature solvent propylene carbonate in the following quantitative ratio of components, parts by weight:
prefabricated enamel one hundred specified acid hardener four organosilicon varnish KO-945 20-26 propylene carbonate 5-10