SU852920A1 - Powder primer composition - Google Patents

Description

The invention relates to the field of the production of polymer powder coatings used in various fields of industry: machine building research institutes, electrical engineering, instrument making and others. There is a known powder primer composition for polyvinyl chloride coatings containing polyvinyl chloride and polyvinyl butyral. The disadvantages of this primer composition are the low adhesion strength of the coatings obtained, the low corrosion resistance. The closest to the invention in technical essence and the achieved result is a powder primer composition comprising a copolymer of ethylene and vinyl acetate with a vinyl acetate content of 20-30 wt.% T The disadvantages of this composition are low chemical resistance of coatings, low adhesion of primers polyvinyl chloride coating applied on top, poor flowability and poor fluidity, as well as high melt viscosity, making it difficult to obtain high-quality coatings walkie-talkie. The aim of the invention is to increase the corrosion resistance and adhesion of the primer to polyvinyl chloride coatings and to improve its processability, the goal is achieved by the fact that the powder primer composition comprising a copolymer of ethylene and vinyl acetate with a vinyl acetate content of 20-30 wt.%, Additionally contains an ethylene copolymer and vinyl acetate with a content of vinyl acetate 5-10 wt,% in the following ratio, wt.%: A copolymer of ethylene and. vinyl acetate with a vinyl acetate content of 20-30 wt.% 60-90 Ethylene-vinyl acetate copolymer with a vinyl acetate content of 5-10 wt.% 10-40 Technologies for the preparation of coatings are as follows. The product to be coated is heated to 220 ° C for 3 minutes and subsequently immersed in a fluidized bath.

powder primer composition, and then in a bath with a fluidized PVC paint. The coatings are melted at 2200 s for 6-8 minutes. Example 1. 10 wt.% The powder of a copolymer of ethylene and vinyl acetate (EVA) with a content of 5.5% by weight of vinyl acetate (VA) are mixed in a laboratory high-speed mixer with 180 g of EVA powder with a content of 20% by weight VA. Mixing i is carried out for 20 minutes. The resulting primer composition is discharged from the mixer and placed in a bath where a fluidized bed is created.

The product to be coated is heated to within 3 minutes and subsequently immersed in a bath with a fluidized powder primer composition, and then into a bath with a fluidized paint of polyvinyl chloride. The coating is melted at 22 (Yas for b min.

Properties of the coatings are given in table. one.

Adhesive strength

bonding primer-pvc paint

n / m

Adhesive bond strength, soil-steel substrate, n / m

Flexibility on a scale of SHG-1 on dry land for 10 days. in 20% aqueous solution of NaOH at 250 s, mm

Resistance in 20% aqueous solution of NaOH at 25 ° C, days

Flowability, grad37

Coefficient pseudo-lique-2,6

Example 2. Under conditions similar to those described in Example 1, a primer composition is obtained consisting of a CEBA with a content of 7% by weight of VA and

Table 1

2500

Exfoliation at RMI-5

3000

Also

On a scale of IG-1

Control by

80 adhesion change (up to zero)

Device Larina40 Nikiforova

Control by 2 changes in the height of the fluidized bed of the powder during fluidization

EVA with a content of 30 wt.% VA in their ratio 25:75 (wt.%).

Properties of the coatings are given in table. 2,

Adhesive bond strength primer-PVC paint, n / m

Adhesive bond strength, soil-steel substrate, n / m

Flexibility on a scale of SHG-1 after exposure for 10 days in a 20% aqueous solution of NaOH at 25 s,

NOH

Persistence in 20% aqueous solution of NaOH at 25 ° С, days

Flowability, hail

fluidization coefficient

Melt flow rate, g / 10 min

Breaking strength, mn / m

Hardness Water resistance, days P, example 3. Under conditions similar to those described in Example 1, a primer composition is obtained consisting of EVA with a content of 10 wt.%

ka, n / m

Adhesive bond strength, soil-steel substrate, n / m

Table

2500 Exfoliation at RMI-5

3000 Exfoliation at RMI-5

3 According to Shkosh-1

above

Control of 200 180 adhesion (up to zero)

37

43 Device LarinaNikiforova 2.6

2.1 Control by

the change in the height of the fluidized bed of the powder during fluidization.

85

117 Device NIRT

6.8

5.5 Machine RMI-5 0,28 0,26 Device M-3.

Over 250 Pv 250

Table 3

Also

3000

2800 and CMEA content 25 May. % ON when their ratio is 40:60 (wt.%). Properties of the coatings are given in table. 3

Claims (2)

Properties Flexibility on the SHG scale after holding for 10 days in a 20% aqueous solution of NaOH at 250 s, mm Durability in a 20% solution of NaOH at 25 ° C, days Flowability, degree Fluidization rate Melt flow rate, g / 10 min. Tensile strength. Mn. Hardness. Water resistance, days. Primers based on the proposed primer composition have high corrosion resistance, high adhesive bond strength with PVC coatings applied on top, improved processability and good appearance. Invention: Powder primer, including ethylene / vinyl acetate copolymer with vinyl acetate content. 20-30 wt.%, Different. By the fact that, in order to increase the corrosion resistance and adhesion of the primer to PVC coatings and {to improve its processability, it additionally contains a copolymer Continuation of Table 3 According to the SHG-1 scale. Control of adhesion change (up to zero). Larina Nikiforova device. Control of change in height of the fluidized bed of powder during fluidization. NIRT device. RMI-5 device. % at the following ratio of components, wt.%: A copolymer of ethylene and vinyl acetate with a vinyl acetate content of 20-30 wt.% 60-90 A copolymer of ethylene and vinyl acetate with a vinyl acetate content of .5-10 wt.% 10-40 Sources of information that are in mind during examination 1. Authors testimony in the USSR 455,135, cl. C 09 O 5/00,. 2. Authors certificate of the USSR 677201, cl. In 05 About 1/22, 1977 rototype).