CS227539B1 - Method of chemical plastisol reinforcement - Google Patents

Description

Gelatin, made by gelatinizing plastisols based on homopolymers or copolymers of vinyl chloride, does not achieve the required properties in many applications. These include hardness, abrasion resistance, compressive strength, adhesion to the substrate and others. These properties can be improved according to known methods by forming a polymer by adding substances mixed with plastisols and capable of acting as a temperature, radical or initiator. Most commonly, they are acrylic or methacrylic acid esters, unsaturated polyesters, epoxy resins, allylic dicarboxylic acid esters, triallyl cyanurate, cyanuric acid, diisocyanates and polyisocyanates, modified phenolic resins, polyaminoamides, polysiloxanes and others. Most of these systems do not react at a normal temperature or react at a negligible rate, and only when the threshold temperature, typically above 100 ° C, is exceeded, polymerization proceeds at the required rate. A disadvantage of all systems based on the free radical polymerization of unsaturated compounds, most often initiated by organic peroxides, is the necessity to overheat the entire volume of plastisol to a temperature at which the half-life of peroxide is sufficiently short and free radicals are sufficiently energy rich.

While the diisocyanates and polyisocyanates are capable of reacting at normal temperature, however, since they preferentially react with residual alcohols and water, which are almost always present in conventional ester type plasticizers, their use is tied to special types of plasticizers. Modified phenolic resins and polyamine amides generally react only at substantially higher temperatures than 100 ° C and their use is exceptional, the epoxy resins are capable of reacting even at normal temperature and the reaction rate can be advantageously controlled by temperature. However, aliphatic polyamines, which are harmful to health, and their adducts with epoxides or other types of crosslinkers, for example anhydrides, are most commonly used for their cross-linking.

- 2,227,539 organic acids react only at higher temperatures. A common disadvantage of all known systems is that after application and heating of plastisol, its viscosity decreases, passes through a minimum in the range of 50 to 70 ° C, and only increases again after further heating. The polymerization reaction of the known systems starts only above this temperature. In this temperature range, plastisol flows down, especially on vertical surfaces, and this cannot be prevented by the addition of thixotropic substances.

The process for reinforcing plastisols according to the invention is based on the reaction between the dicarboxylic acid anhydride dissolved in plastisol and the diamine or polyamine which forms the second component or is dissolved therein. Mixing the two components at normal temperature immediately results in the reaction of the diamine or polyamine with the anhydride. The polyamide formed in the plastisol forms a heterogeneous phase and acts as a reinforcing network. The viscosity of the plastisol produced by the resulting polyamide increases markedly, thereby avoiding deposition of the applied plastisol. The heating of plastisol completes the reaction between the anhydride and the diamine residues, and therefore the viscosity does not decrease as a result of the heating and lies in a substantially higher range than that of the non-reinforced plastisol. By gelatinizing plastisol, the polyamide chains are spatially fixed in the gelatinate and thereby significantly improve its mechanical properties. Since the polyamide is formed before gelation begins, it also precipitates on the substrate to which plastisol is applied, thus forming an adhesive layer that sprays the connection between the substrate and the gelatin.

In contrast to known solutions, the method of reinforcement according to the invention gives the same increase in hardness of gelatin at substantially lower doses of the reinforcing component. In addition, the method according to the invention allows an immediate increase in the viscosity of plastisol after mixing the components, which, however, is partially reversible and can be reduced by applying shear stress. By intensively mixing the plastisol after mixing the components, the polyamide structure is partially destroyed so that the plastisol can be applied. When gelatinizing, the polyamide network is formed and the resulting gelatin hardness is the same as if the polyamide chains had not been broken.

- 3 227 539

Anhydrides, diamines and polyamines, as well as the resulting polyamide, will cure the epoxy resins, thereby further enhancing the effect of the system of the invention. Epoxy resin removes unreacted amines from the system and their adducts are nonvolatile and non-toxic · This eliminates the hygienic risk associated, in particular, with diamines and polyamines in cases where the amine and anhydride are not in stoichiometric ratio ·

Example 1

One component is a plastisia, composed of 52.8% by weight of a vinyl chloride-vinyl acetate copolymer having an average grain size in the range of 0.1 to 40 microns, a K value of 70 and a vinyl acetate content of 5% by weight, 10% by weight of micronized limestone. 30% by weight of phthalic esters to Cg, 3% by weight of octyl stearate, 3% by weight of epoxy resin having an epoxy number of 0.5, and 0.2% by weight of dibutyltin mercaptide, and 1% by weight of methylhexahydrophthalic anhydride. The second component consists of 32% by weight of 3,5,5-trimethylcyclohexylamine and 68% by weight of dibutyl phthalate. The two components are mixed at a ratio of 100: 4.5 in the mixing head during pouring into the mold. The plastisel is then gelatinized at 150 ° C for 12 minutes in a 3 mm thick layer.

Example 2

One component is a plastisia, consisting of 28% by weight of an emulsion paste-forming polyvinyl chloride having a K-value of 68, a further 20% by weight of a suspension polyvinyl chloride having a grain size below 100 micrometers and a K-value of 62-68. % by weight of di-2-ethylhexyl adipate, 1% by weight of dibutylcinmaleinate, 5% by weight of methylhexahydrophthalate hydride, 4% by weight of epoxy resin having an epoxy number of 0.5. diethylenetriamine, 20% by weight of 3-aminomethyl-3,5,5-trimethyloyclohexylamine, 20% by weight of palm-type epoxy resin having an epoxy number of 0.5 to 0.55, 20% by weight of di-2-ethylhexyl phthalate, 30% by weight. % dibutyl phthalate · Both components are mixed at applied in a 100:20 spray gun and a 1 mm thick layer was gelatinized at 180 ° C for 5 minutes.

Example 3

Plastisol, consisting of 30% by weight of a vinyl chloride / vinyl acetate copolymer having a K-value of 70 and containing 5% by weight of vinyl acetate perchlorate, 25% by weight of an emulsion paste-forming polyvinyl chloride of K-value of 68, 5% by weight of micronised limestone. 2 wt.% 2-ethylhexyl phthalate, 1 wt.% Dibutylcinmaleinate, 2 wt.% Zinc octoate, 0.8 wt.% 3-aminomethyl-3,5,

- trimethyloyclohexylamine, a further 1.3% by weight of n-dodecenyl succinic anhydride, is mixed, increasing its viscosity due to the reaction of the anhydride with the diamine. Such plastisol is used as a single component by mixing it on a dissolver high speed stirrer prior to application. viscosity decreases. It is poured into molds and gelatinised for 10 minutes at 170 ° C in a 3 mm thick layer.

The method of chemical reinforcement of plastisols according to the invention is advantageous especially when the plastisol as a protective coating is applied to flat or spatial formations, in particular metal. It is also suitable for bulky fillings in cavities where the entire volume cannot be sufficiently overheated. It is further suitable for increasing the adhesion of gelatin to the substrate, whereby the resulting polyamide serves as an adhesive component. Compared with the most widely used methods of reinforcing plastisols with acrylates, the method of the invention is significantly more effective. To increase the hardness of the gelatin from 65 to 75 ShA, a dose of 2 weight percent 1,4-butanediol dimethacrylate and 0.04 weight percent benzoyl peroxide is used according to the known method. For the same increase in the hardness of the same plastisol, a dose of 5,227,539 to 0.4 wt.% Of methylhexahydrophthalic anhydride and 0.4 wt.% Of 3-aminomethyl-3,5 _t.

Claims (3)

OBJECT OF THE INVENTION 227 539 Process for the chemical reinforcement of plastisols based on vinyl chloride homopolymers or copolymers, characterized in that two components are mixed at normal temperature, one of which is dicarboxylic anhydride and the other of which is a diamine or polyamine or an adduct thereof with an epoxy resin, wherein at least one of these components is dissolved in plastisol such that the sum of the doses of anhydride and amine component is 0.2 to 20 weight percent based on plastisol and the molar ratio of anhydride component to amine component is in the range 0.1: 1 to 2 , 5: 1, and after mixing the two components, the plastisol is heated to the gelatinization temperature · 2. The method of claim 1, wherein the anhydride component is methylhexahydrophthalic anhydride or nonenylsuccinic anhydride or n-dodecenylsuccinic anhydride or a mixture thereof. 3. A process according to claim 1, wherein the amine component is diethylenetriamine or triethylenetetraamine or 3-aminomethyl-3,5,5-trimethylcyclohexylamine or dipropylenetriamine or a mixture thereof or an addition product of at least one of said amines and a palm-type epoxy resin with epoxy number 0.5 to 0.55, wherein the weight ratio of amine to epoxy resin is in the range of 3 to 1 to 0.8: 1.