CS197030B1 - Protective means for separation of moulds by treating the reactive polymeres - Google Patents

Abstract

The invention relates to a protective device for mold separation during spraying reactive polymers, e.g. at production of molded polyurethane parts, that have a wide area of use in the footwear industry. The preservative comprises 0.01 to 4 wt. % silicone polymer nu. <C0,00-dihydroxypolydiorganosiloxene base With a viscosity of 5θθ already 1 000 000 rnPas, 0.01 to 5 wt. % of catalyst formed organometallic salts of carbon acids, Q2 to 10 wt. % silicone oil β linear structure of viscosity 10 to 5,000 mPae and 77 to 99.67 wt. decomposed on the basis of chlorinated hydrocarbons, alkylaromates or petrol.

Description

The author of the invention BTBT.EK JÁN ing. and

KOPAL PAVEL ing. CSO., PARTIZÁNSKE (54) Protective agent for mold separation in the treatment of reactive polymers

The invention relates to a protective agent for mold separation in the processing of reactive polymers, e.g. in the manufacture of molded polyurethane parts having a wide range of use in the footwear® industry.

The preservative comprises 0.01 to 4 wt. % silicone polymer nu. base <C, 00 -dihydroxypolydiorganosiloxene with viscosity 5θθ already 1 000 000 rnPas, 0,01 to 5 wt. % of a catalyst consisting of organometallic salts of carbon acids, Q2 to 10 wt. % of silicone oil by β linear structure with a viscosity of 10 to 5,000 mPae and 77 to 99.67 wt. based on chlorinated hydrocarbons, alkylaromates or petrol.

197 O3O

197 030

The present invention relates to a mold release agent for the processing of reactive polymers, for example in the manufacture of molded polyurethane parts having a wide range of applications in the shoe industry for the production of wedges, socks, heels, hooves and the like. of polyurethanes for the automotive, furniture and leather industry by the ln alta method ”.

In the last Rokooh stream raatie produce so called. reektímoyoh polymers for products of precise shape, with compact surface and lightweight cell nucleus. Typical Representatives! of these polymers are polyurethanes produced by the in-situ method. The main advantage of this technology is the preparation of polyurethane foam masses directly in the shape of the desired work piece. This eliminates the costly equipment for preparing the polymer itself, re-granulating it with the blowing agent and foaming it to the desired shape, as is the case with conventional plastics being processed into lightweight articles.

Since the basic ingredients for the preparation of such articles are very reactive, the hemi-hydroxides ea bind to each substance with active hydrogen. Therefore, before pouring the reaction mixture, it is necessary to form a thin, inert film on the mold surface, which would prevent the reaction mixture from sticking to the surface of the mold, being hydrophobic and reducing the surface tension between the mold and the product thereby facilitating removal of the moldings. When the product is further treated, for example by painting, the release agent is required to be easily removed from the surface of the article (e.g., by immersion in an organic solvent bath).

The choice of soparating agents is dependent on the composition of the reaction system, which may be, for example, polyurethane, may be polyether, polyester, flame-retarded, or physically. These compositions are usually solutions of silicone oils, silicone polymers in easily persistent solvents, or solutions and dispersions of waxes, or combinations of silicones and waxes.

When only silicone oils are used for the separation, the haloalkenes present in the reaction mixture dissolve the film formed by them and thus the separating effect is lost. The silicone oil, penetrated into the surface layer of the reaction mixture, brightens the system and thereby slows the reactivity of the reaction on the surface of the object.

When silicone polymers are used, the protective film formed has a significantly higher viscosity. The haloalkenes present in the reaction mixture do not dissolve it, but the hydroxyl groups, by which the silicone polymer macromolecule is terminated, react with the isocyanates, resulting in a gradual chemical bonding of the reaction mixture to the separation layer and rapid fouling. For these reasons, combinations of silicone polymers and oils are most often chosen for separation. The use of _x provides relatively good separation effects, but after several days of use, the mold surface is gradually clogged with the agglomerated release agent / polyurethane mixture. The reacted mixture is removed after dissolution in tetrahydrofuran or dimethylfoxmamide.

Wax release agents have a similarly limited use. The limiting factors are: the presence of active hydrogen in the wax macromolecule chain, melting point,

197,030 reaction and heat, crystallization properties and surface tension. At the low melting point of the wax, due to the reaction heat of the reaction of the isocyanate with the polyols, it is melted and subsequently absorbed into the polyurethane mass, thereby losing its heat-extinguishing properties. A higher melting point of the wax results in mold fouling in multi-application application. The retention capacity and crystallization properties of the wax are the basic prerequisites for the formation and stability of its wicking in the preparation of the eeparation compositions. The surface tension as a result of the cohesion and adhesion properties determines whether removal of the moldings from the mold takes place on the boundary surface of the release agent - polyurethane. The choice of a suitable wax as the basic component is therefore a very demanding and efficient release agent can only be achieved by extensive and time-consuming series of tests.

If the mold surface protective layer is formed from silicone rubber, a breaker and a catalyst, the moldings are rubbed off on a separating layer on the suoho during removal from the mold, which also involves pulling out.

An analogy of this method is the formation of a Teflon film on the surface of the mold. Molds treated in this way make it possible to mold several thousand moldings without renewing the separation layer. A disadvantage of this method of producing a long-term eeparation effect is that after spraying the Teflon die, the mold should be heated at 350 ° C for 20 to 30 minutes. If you do not rotate all the places on the mold or damage the Teflon film, it is necessary to repeat the prooes *. In addition, non-metallic forms exclude the use of this protective layer formation method.

These deficiencies ea are overcome by providing a protective layer of a composition according to the invention which is subsequently to contain 0.01 to 4% by weight of a silicone polymers from the group of substances such as eu polyalkoxyeiloxanes having a carbon number of 1 to 6, dskaetoxytetrasiloxau or polymethylhydroxyiloxanes or non-cycloocyanates, 0.01 to 4% by weight of a silicone polymer based on <C, CO-dihydroxypolydiorganoeiloxane having a viscosity of from 500 to 1 000 000 mPa.e,

0.01 to 5% by weight of the crosslinking catalyst, which are the organometallic salts of the carboxylic acids of metals, most preferably oine, lead, cobalt, or zinc,

0.2 to 10 weight percent of silicone oil linear structure with a viscosity of 10 to 5,000 mPa.e. For ease of application to the surface of the articulated mold ea, the composition will dissolve in 99.67 to 77 weight percent gasoline peroxygen, optionally chlorinated hydrocarbons, or toluene.

After the application of this mixture to the surface of the heated form, most often by shaking, the solvents are evaporated and the C, Cd-dihydroxypolydiorganoeiloxane of the following structure

HO-Si-0

Si - 0

Si-OH

197,030 η = 500 to 1,000,000

R β aryl, an alkyl of 1-4 carbons will react with the crosslinker. Polyalkoxysiloxanes whose alkyls have less than 6 carbon atoms are used as the cross-linking component. Also included in this group is ethyl silicate 40, which is the most widely used crosslinker due to its good stability, ease of availability, low oen. The chemical composition of ethyl silicate 40 corresponds to the formulas of decaethoxytetrasiloxane. The second most important group of crosslinkers are the polymethylhydrosiloxanes linear or ocyclic or other mixtures. Crosslinking agents of this class are very effective and are particularly suitable in those cases where it is necessary for the vulcanization to take place in the shortest possible time.

Suitable catalysts are metal or organometallic salts of carbonic acids of a wide variety of metals, but most preferably oin, lead, cobalt, or zinc. The meohanism of the creation of the © jete space can be illustrated obeone by the following scheme:

The effect of the invention lies in the combination of the following properties: The catalysts which facilitate the crosslinking reaction of the crosslinking ε, CJ --dihydroxypolydiorganoxyloxane also act as rapid catalysts for the reaction of isocyanates and polyols in the surface layer of the article. This leads to an accelerated end of the reaction, i.e. a loss of tack of the polyurethane surface, thus allowing easier removal of the moldings from the mold. Silicone oil, which is one of the components of the release agent, acts as a lubricating layer in the rubbing of the polyurethane-mold surfaces at the extrusion stage. The silicone oil acts further than the softener and the foaming agent passes through the oohrannoj layer. The optimum density of the mesh prevents this layer from being absorbed into the polyurethane, but allows it to dissolve in organic solvents in cases where subsequent coloring and lacquering of the produced dleloa is required. The above-mentioned silicone oil remains, even after washing in organic solvents in a non-toxic amount, in the longitudinal coating layer and acts as a surfactant for coloring and varnishing, thereby achieving a uniform coloring and varnish coating. The rapid loss of tack of the polyurethane surface and its fastening effect facilitates removal of the mold from the mold and allows to shorten the theoheologic sasses from the mold, thereby achieving higher productivity.

Examples:

Example 1

Dissolve 0.02 weight percent of ethyl silicate 40, 0.03 weight percent of silicone polymer viscosity of 1000 mPas, 3 weight percent of diisobutyloindicoponate and 6.95 weight percent of silicone oil having a viscosity of 500, respectively, in 90 weight percent gasoline distillates with a distillation range of 60-80 ° C. mPas. The mixture is homogenized by milling and shaking and applied to a mold surface heated to a temperature of 40 to 60 ° C. The homogenized polyurethane mixture is then poured into the mold, sealed and held for 3 min. is a mold cavity filled with a reaction mixture that is reacted on the blank so that the article can be demolded.

Example 2

For polyether polyurethane systems foamed physically, a mixture of the following composition may be advantageously used to form the protective surface: 3.5 weight per cent of tetrahydrofurfurylsilicate, 0.5 weight per cent of silicone polymer having a viscosity of 5000 mPas, 5 weight per cent, are dissolved in 82 weight per cent of trichlorethylene peroxygen. n-butyloindicaponate and 9 wt.% silicone oil penent with a viscosity of 200 mPa.s. After homogenization of this mixture, 15 wt.% Of molten wax was poured into the mixture while stirring with a thin additive. The resulting mixture ea was deposited on the surface of the heated mold at least 30 seconds before pouring the reaction mixture. After 3.5 min. y it is possible to demold the product *.

Example 3

The following composition of the eeparation proethriod is used to form a flame-retardant layer on the molds in the production of a hard polyurethane mixture:

% by weight of a mixture of gasoline with a distillate range of 60 to 80 ° C and trihlorethylene in a ratio of 1: 1,

197 030

0,03 weight per cent of linear polymethylhydrosiloxane with a viscosity of 500 mPa.e,

0,05 weight per cent of silicone polymer viscosity 500 000 taPa.s,

0.20 per cent by weight of di-n-butyloindilaurate penent,

3.72 weight percent of silicone oil having a viscosity of 500 mPa.s.

After homogenization, the mixture is sprayed onto a surface of molds having a temperature of 40 to 60 ° C. The surface layer is reacted in 3 minutes. After this time, the molding can be demolded.

The aforementioned release agents can be used to protect the molds during the processing of other reactive polymers such as e.g. epoxy resins, phenol-formaldehyde, melamine or polyester resins.

OBJECT OF THE INVENTION

Claims (3)

OBJECT OF THE INVENTION A protective agent for mold separation in the treatment of reactive polymers, characterized in that it comprises from 0.01 to 4% by weight of a silicone-based peroxygen crosslinker, from 0.01 to 4% by weight of a silicone-based silicone polymer based on ού, Οϋ- dihydroxypolydiorganoxiloxane up to 1 000 000 mPa · s, 0.01 to 5% by weight of a crosslinking catalyst composed of organometallic salts of metal carbonates of the most preferred oine, lead, cobalt or zinc, 0.2 to 10% by weight of a linear structure silicone oil having a viscosity of 10 up to 5,000 mPa.s and 99.67 to 77 percent by weight of a solvent based on chlorinated hydrocarbons, alkylaromates or petrol. 2. A preservative according to claim 1, wherein the silicone polymer crosslinker is selected from the group consisting of polyalkoxysiloxanes wherein the number of carbons in the alkyl is 1 to 6, decaethoxytetrasiloxane, polymethylhydrosiloxane, linear or oxycarbone. . 3. A mold release agent according to items 1 and 2, characterized in that it contains in addition 0.1 to 20% by weight of a wax penent with an acid number of 0.1 to 60, based on the weight of the base mixture.