DE1290273B - Coating of objects using the fluidized bed sintering process - Google Patents

Description

1 2

When coating objects, in particular that the disadvantages described above do not

those made of metals, after the vortex sintering process can occur.

Ren is known to be the counter-object of the invention is the use of

was, in particular a metal part, in an oven, heated mixtures of fine-grain polyvinyl chloride and then briefly in the vortex 5 block polymer with a K value of up to 60 and

submerged in bed. The heat capacity of the metal is plasticizer for coating objects

Sufficiently large to cover the coating material within the fluidized bed sintering process,

to alloy out completely for half a few seconds. With such powders, coatings can be removed

Subsequently, if necessary, by Ab- the vortex sintering process can be achieved with regard to

flame or quench the surface io smoothness, gloss and freedom from pores better surfaces

be improved. Since the deformation and film image result as if the usual suspension resp.

can only be used under the influence of heat without emulsion polyvinyl chloride types

Applying pressure is done, too. When comparing products with the same

Working temperatures compared to other process K-value are the melting times during application

at least 100 ° C higher. That is less for the efficiency of block polymers. This was on

In the case of internally suitable products, therefore, apart from the reason for the Belgian patent 571600, they do not have to be

excellent flow properties good thermal foresee. So you can use low preheating

Have stability. apply temperatures, which increases the stabilization

The surface coating of metals has been simplified or the stabilization costs have been reduced. or the vortex sintering process so far predominantly at so one uses a product with comparatively Polyamides, cellulose acetobutyrate and polyethylene have a higher K-value, making the mechanical self-applied. Because of its good chemical resistance, the coating can be improved. The meditation and its particularly easy accessibility chanical properties are due to the smoothness and it is desirable to also use polyvinyl chloride after the uniformity of the coating in advance To process fluidized bed processes. 25 already optimal. The good flow properties of

Polyvinyl chloride powder without further additives Polyvinyl chloride block polymers allow it

Because of their low thermal stability, there are also coatings with a particularly low level

from the outset, but also to achieve stabilized polyvinyl wall thickness.

Chloride is more sufficient for the fluidized bed sintering process because of the use of block polymers of vinyl Flow properties not suitable. Through 30 chlorides at vortex sintering it was not obvious. The addition of plasticizers improves the flow behavior of the The skilled person thinks of the term »poly mixtures so much improved that in the case of vinyl chloride "at first only suspension and Sintered coatings that are closed by sintering are obtained from emulsion polymers of vinyl chloride because this can. The distribution of plasticizers and stadia are by far the most common types of polyvinyl chloride bilizer must be so uniform that each individual 35 (cf. for example Janotta, »Manufacture and PVC particles as similar as possible to the plasticizer and properties of the polyvinyl chloride «in» the plastic stabilizer components contains. In the case of unequal soft processors, 1960, pp. 225 to 228, in particular the distribution of the processors, there is an even, smooth over- p. 194, right column, paragraph 2). For the professional train not available; imperfect stabilizer - there was also no evidence that block polymers distribution leads to local decomposition points in the 40% of the vinyl chloride would give better results Coating. It has been shown that a sufficient emulsion or suspension polymer, especially Homogenization by using a rapid it is generally known (cf. for example Küchler, mixer is achievable. Due to the "Polymerisationskinetik" (polymerisation kinetics) occurring during the mixing process, Berlin, 1951, p. 212 Frictional heat usually becomes a last paragraph) that suspension polymerization does not get dry powder, otherwise the oven 45 can be different than a »water-cooled block polymer or fluidized bed dryer. sation «.

In order to be sufficient for the fluidized bed sintering process, the hardness of the coatings lets itself through once

Obtaining a narrow grain size distribution will vary depending on the size of the plasticizer. as

then sifted or wind sifted. Plasticizers can be used proportionally with particular advantage

The measures described above are still 50 or only used dicyclohexyl phthalate not sufficient to be used when coating objects. This solid product only acts as a plasticizer when working with polyvinyl chloride after the fluidized-bed sintering process (to obtain satisfactory coatings. From the improvement of flowability), while the patent 571600 overlooks it is known that tensile forces are completely hard at room temperature.
Polyvinyl chloride according to the fluidized bed sintering process has been found that satisfactory coatings can be obtained with the invention if PVC protective coatings are applied using a fluidized fluidized sintering process at the same time as the plasticizer, compared to a prior amount of water mixed into the polyvinyl chloride Primer will adhere much better to it. The water can, however, be obtained when the metal is stored if the adhesion promoters evaporate during the fluidized sintering powder, which means that the powder production does not have a direct effect on the coatings. The mixing in of the adhesives is made for the purpose of preserving. In addition, mixed poly water vapor bubbles containing carboxyl groups can cause the coatings to be porous, merizate of the vinyl chloride with a part and finally the water can lead to corrosion or the total amount of the heat stabilizer required for the PVC fluidized sintering device 65 powder required for fluidized sintering. and only then added to the PVC powder. Epoxy

In the case of the mixtures used according to the invention, resins are dissolved in the plasticizer and with

if, on the other hand, no water needs to be added, so it can be added together in a high-speed mixer

PVC powder given; therefore also have liquid Epoxy resins have been found to be particularly suitable. This way of working becomes the prerequisite for good Adhesion of the PVC coatings on the metal surfaces ensured, namely that the mixed in Adhesion-promoting resins are evenly distributed in the fluidized bed powder.

In the following examples, these are parts by weight.

example 1

In a high-speed mixer, 67 parts of PVC block polymer with a K value of 55 and 2 parts of titanium dioxide were added (Rutile modification) a mixture of 28 parts of dioctyl phthalate and 3 parts of stabilizer (Dibutyltin dimercaptide) given slowly. Internal friction occurred within 20 minutes heated to 110 ° C. After cooling, it was screened through a 0.5 mm sieve. The powder obtained was whirled up in the fluidized bed. The coatings on sandblasted iron sheets (thickness 3 mm) were obtained after preheating to 350 ° C in 1 to 3 seconds.

Properties of the coating:

100% modulus 106 kg / cm ²

Tear strength 128 kg / cm ²

Elongation at break 138%

Cold break temperature -35 / -4O ⁰ C

Low-temperature impact temperature -31 / -35 ° C

Shore hardness A82, C55, D 31

Example 2

Using a PVC block polymer With a K value of 60, as described in Example 1, a coating with the following properties was obtained:

100% modulus 116 kg / cm ²

Tear strength 187 kg / cm ²

Elongation at break 215%

Cold break temperature .... -40 / -45 ⁰ C
Cold impact temperature .... -36 / -38 ° C
Shore hardness A84, C58, D32

Example 3

A fluidized bed powder was obtained as in Example 1 using the following composition:

74 parts of PVC block polymer with a K value of 55, 21 parts of dioctyl phthalate,

3 parts of dibutyltin dimercaptide,

2 parts titanium oxide.

The coatings obtained with this powder had the following properties:

100% modulus 192 kg / cm ²

Tear strength 219 kg / cm ²

Elongation at break 146%

Cold break temperature -5 / -10 ° C

Cold impact temperature 20 ° C

Shore hardness A94, C76, D52

Example 4

A fluidized bed powder was obtained as in Example 1 using the following mixture:

74 parts of PVC block polymer with a K value of 55, 10.5 parts of dioctyl phthalate,
10.5 parts of dicyclohexyl phthalate,

3 parts of dibutyltin dimercaptide,

2 parts of titanium dioxide.

Characteristics:

Tensile strength 231 kg / cm ²

Tear strength 253 kg / cm ²

Elongation at break 115 to 155%

Cold break temperature + 10 / + 15 ⁰ C

Cold impact temperature .... 20 ° C

ao Shore hardness A 97, C 91, D 69

Example 5

A fluidized bed powder was obtained as in Example 1 using the following mixture:

74 parts of PVC block polymer with a K value of 55, 21 parts of dicyclohexyl phthalate,

3 parts of dibutyltin dimercaptide,
2 parts of titanium dioxide.

Characteristics:

Tensile strength 330 kg / cm ²

Tear strength 289 kg / cm ²

Elongation at break 11%

Cold break temperature .... 20 ° C

Cold impact temperature ^{2O 0 C}

Shore hardness A96, C94, D73

Example 6

In a high-speed mixer, 70 parts of PVC block polymer with a K value of 60 and 1.5 parts of titanium dioxide were added to a homogeneous mixture of 4 parts of a copolymer composed of 85% vinyl chloride, I4o / _O vinyl acetate and 1% maleic acid and 0.5 part dibutyltin dimercaptide. At high speeds of the mixing tool (1500 rpm) the mixture was mixed and a solution of 2 parts of liquid epoxy resin and 2 parts of dibutyltin dimer cappide in 20 parts of dioctyl phthalate was slowly added. As a result of the internal friction that occurred, the powdery material was heated to 150 ° C. within 20 minutes. After cooling, it was sifted through a 0.5 mm sieve.

Claims (3)

Patent claims: 1. Use of mixtures of fine-grain polyvinyl chloride block polymer with a K value up to 60 and plasticizers for coating objects using the fluidized bed sintering process. 5 6 2. Use of mixtures with poly fillers and dyes - and vinyl chloride or vinyl chloride with a narrow particle size distribution with vinyl chloride-vinyl acetate copolymers between 0.03 and 0.2 mm according to claim 1. unsaturated carboxylic acids and / or epoxy 3. Use of mixtures containing additives finely divided resin, according to Anan Stabilizers - if necessary pigments, 5 claim 1.