DE1285651B - Process for the production of polyvinyl chloride coatings - Google Patents

Description

This invention serves to improve the 2193 613 to be homogeneous at elevated temperature Production of polyvinyl chloride coatings from a solution of polyvinyl chloride and plasticizer organosols, whereby one can be put under this designation.

Usually polyvinyl chloride dispersions in liquid It has now been found according to the invention that Understands plasticizers. These dispersions 5 suffered from these disadvantages of the previous methods of preparation relatively small amounts of volatile solution points of polyvinyl coatings due to application agent added to the physical property of a dispersion of polyvinyl chloride in a flüchschaften to modify the dispersions for the purpose of naphthalene derivative-containing carrier liquid relief the application on surfaces. ability and removal of the carrier liquid by Er-Ob the polyvinyl chloride dispersions additional heat can be overcome in that Containing volatile solvents or not, which affect the polyvinyl chloride dispersions to a minimum The purpose of the liquid plasticizer is at least 70 percent by weight of one or more monoals Carriers for the polyvinyl chloride particles and also containing methyl and / or dimethyl naphthalenes applied as a homogenizing agent when heating the volatile carrier liquid and applied to 130 Preparation to act to a uniform together- 15 to 250 ° C are heated. When heated to the supply hanging cover; the heating temperature indicated initially remains the disperratur is usually in the range from 160 to sion still obtained until the methylnaphthalenes im 250 ° C, but depending on the type of dispersion, they are substantially removed, d. i.e., only after that and the length of time during which they are exposed to the elevated monomethyl and / or dimethylnaphthalene temperature exposed, fluctuates. When the soft table has completely evaporated, the desired Vermacher steps in serves to melt the polyvinyl chloride particles into one with the polyvinyl chloride in the coating To give flexibility; commonly used homogeneous layer.

Plasticizers are esters of phthalic acid and phos- The coatings obtained in this way are free of fiIm-

phosphoric acid, for example dioctyl phthalate, dinonyl cracks, as in the known method in

phthalate and tricresyl phosphate. 25 Burn-in can easily occur. In this procedure

Although for many purposes the presence of one is namely first a solution or imagination

Plasticizer is advantageous, these substances make gel, from which the solvents only then come out.

in certain applications is a disadvantage, since steaming must shrink the gel and

the plasticizer at elevated temperatures is at risk of cracking. The branding of the inven-

can volatilize from the coating, so that its 30 proper dispersion can be in a larger

physical properties are changed. The temperature range can be made as this

Plasticizer can also be used in any other organ- hitherto in the case of the known preparations with the

migrate niche material with which the coating in usual amounts of plasticizers was possible.

Touch is what in turn leads to a change The polyvinyl chloride produced according to the invention

the physical properties of the coating. 35 coatings are also more chemically resistant and

A major disadvantage is that the hardeners than the previously known coatings. Is in

The ability of the coating to withstand attack has, in some cases, particularly good adhesion

of chemicals such as acids, alkalis and detergent metal surfaces, one of the

Gentien, due to the presence of the plasticizers, suitable adhesive primers are applied

is significantly reduced. Turn 40.

Plasticizer-containing polyvinyl chloride coatings It should be noted that the inventively

can also tend to turn faster with increased turning organosol preparations in the usual way

Temperatures to soften as unplasticized pigmented using known mixing devices

Coatings and will become un- at elevated temperature. The

desirably sticky. The contact of solution dispersions in the usual way by spraying,

by means of the coating, a part of dipping, roller application and the like can also be applied,

or leach out all of the plasticizer, which The dispersions can still be used as additional additives

in turn, an undesirable change in the physical other components, such as synthetic resins,

calic properties results. surfactants, polyvinyl chloride stabilizers

But it has already been established that with a 50 and relatively small amounts of the usual soft thin polyvinyl chloride coating, for example up to macher as well as other organic solvents 0.25 mm thick, a boiling point that is entirely one unit lower than that of the methyl substances grown together Coating without any softening contains naphthalenes. The amount of additive is sufficiently flexible. The plasticizer given here is determined by the hardness of the if organosols of the polymer are used, which vary in the coating to be produced, to be burned. It is also known that polyvinyl chloride is always lower than normal soft powder in tetrahydronaphthalene in conjunction with macher amounts; the applied amount should be one liquid so-called active agents, such as considerably less than 50% by weight benzyl alcohol or dimethyl phthalate, percent of the polyvinyl chloride to be dispersed. As mentioned, and to incorporate this dispersion on a base, pigments and can also be incorporated into the dispersions burn. Extenders are incorporated; treated clays,

It has been found, however, that uses, such as bentonite clays, are special as extenders

of tetrahydronaphthalene as the only dispersion usable.

medium is not satisfactory, as the stoving purpose of adding the lower boiling point

the applied layer tearing the film with 65 solvent consists in the rheology of the dis-

a crocodile skin effect prevails. persion to facilitate its use

Is used as a plasticizer z. B. Modify amyl, as is the case with the known organosols

naphthalenes, it is commonly practiced according to U.S. Patent.

The baking conditions for the production of cohesive, uniform coatings can vary from 30 minutes at 130 ⁰ C to 40 seconds at 300 ° C, depending on the thickness of the applied film, and the thermal capacity of the substrate on which the film was applied.

The method according to the invention is also suitable for coating aluminum, steel or others Metal strips in a continuous flow, the strips with or without primer through a roller application machine or another suitable application device coated and the Coatings are cured by passing them through an oven.

example

100 g powdered polyvinyl chloride, 200 g mixed methylnaphthalenes (boiling range 209 to 265 ° C), 14 g titanium dioxide (rutile), 10 g barite and 2 g dibutyltin laurate are put in a ball mill for 40 hours marry. The dispersion obtained is sprayed onto a suitably primed steel panel and 10 minutes heated to 180 ° C. The stoved coatings are 0.00508 cm thick and are chemically resistant with excellent properties.

The mixed methylnaphthalenes used in the above example are commercially available alkylated naphthalene product which is approximately 60% monomethylnaphthalene and approximately 15% dimethylnaphthalene and has a Kauri-Butanol value of and a specific gravity of 0.987.

Claims (2)

Patent claims: 1. Process for producing polyvinyl chloride coatings by applying a dispersion of polyvinyl chloride in a volatile carrier liquid containing naphthalene derivatives and removing the carrier liquid by heating, characterized in that polyvinyl chloride dispersions in at least one 70 percent by weight of one or more monomethyl- and / or dimethylnaphthalenes containing volatile carrier liquid and heated to 130 to 250 ° C. 2. The method according to claim 1, characterized in that dispersions are applied, the additional pigments, fillers, stabilizers and plasticizers in the usual amounts contain.