SE416396B - PROCEDURE AND FORM FOR GLASS FORM SHAPING - Google Patents

Description

_A'780833lf-2 10 15 20 25 30 35 2 the glass first to a post or a substance by bringing it into contact with a surface which limits the cavity and which is in contact with the glass or shapes the glass, of a post or blank form , and this blank or post is then formed into the finished article in a finished-A shape by contact with the surface of the finished mold which defines the cavity and which forms or is in contact with the glass. The shaping of the blank or post and the shaping of the finished object based on the post or blank takes place without relative rotation between the glass and the respective molds. Common glass-forming devices which work with hot metal molds are the conventional I.S. glass-forming machines, which operate either according to the blowing process or according to the press-blowing process, and Owen's glass-forming machine. When no steam cushion is used when using the full blowing process, it is generally considered that the glass in this forming method is in contact with the surface of the mold which forms the glass and which limits the cavity. Those skilled in the art know how important the properties, such as the properties of the surface that limits the cavity, in a hot metal mold are for the molding process to take place properly.

The inner surface, i.e. the surface of the mold, which limits the cavity and is in contact with or shapes the glass, must have such properties, including proper heat transfer and proper release of the glass, so that undesirable quality defects are avoided. The hot metal molds must also be able to be heated sufficiently to avoid sudden cooling of the glass, which would otherwise lead to the formation of cracks. It must be weighed against this that the hot metal molds must not be made too hot, since the glass tends to stick to the cavity-limiting surface of the mold and give a finished object with quality defects due to the glass sticking to the mold. In an attempt to make the process of forming glass with hot metal molds run more smoothly, it is commercial practice to lubricate the molds to facilitate the release of the glass with such materials as oil, graphite, grease. sulfur, rubber, old shoe heels and the like. This type of lubrication clearly has obvious shortcomings and limitations. For example, this lubrication is usually based on the subjective assessment of independent glass machine operators, something that does not contribute to reliability. Another shortcoming of this method is that the materials are normally present in moist organic carriers, which on contact with the hot metal mold evaporate and contaminate the general molding surface with impurities.

Czechoslovak Patent 128,236 entitled "Lubricants for Glass Molds" and the corresponding abstract in Chemical Abstracts, Volume 70, 1969, page 195, Abstract No. 108868Y, shows a lubricant for glass molds, which lubricant is formed of an organopolysiloxane and colloidal graphite. see Chemical Abstracts, Volume 60, Abstract No. 763D, entitled "Coatings Which Prevent Sticking of Molten Glass to a Mo1d", which describes colloidal graphite and a silicone. Colloidal graphite is a permanent suspension of finely ground natural or manufactured graphite dispersed in a liquid carrier and it is usually marketed as a dispersion or suspension concentrate containing about 10-20% by weight of graphite. The particle size of this colloidal graphite is in the order of 1 pm and finer and consequently this is an extremely fine material with a large outer surface. As will be apparent from the following examples, the use of colloidal graphite is unsatisfactory because the abrasion obtained with such materials cannot be combined with the glass industry's - using the full blowing method - need for glass forming methods which are fast, high quality and inexpensive. . For a description of colloidal graphite, see Kirk-Othmer Encyclopedia of Chemical Technology, Volume 4, 1964, page 325.

U.S. Pat. No. 3,347,650 describes some difficulties in lubricating molds. This patent then describes a lubricant in the form of a solid film on a mold, which film is formed, for example, from a lead monoxide powder in admixture with '780-8334-2 10 15 20 25 30 35. 4 graphite. Those skilled in the art will readily recognize the inadequacy of such a method due to the toxicity of lead. DE OS 2 303 861 relates to a sprayable lubricant for glass container molds, which lubricant is sprayed on after each molding cycle. For the sprayable lubricant, graphite was used in a finely divided solid organic polymer with a graphite to organic polymer ratio of about 1: 0.1 to 1:15. However, DE OS 2 303 861 in no way describes any permanent or hard lubricant in film form on the mold, such as the surface of the mold which limits the cavity, is in contact with the glass or shapes the glass, the latter referring to spraying after each molding cycle. Against this background it will be appreciated that within the glass forming area where the full blowing method is used, whereby in the forming steps there is no relative rotation of the glass and the mold, there is a need for a glass release agent or a lubricant on the surface of the mold which is used. - limits the durability, which means does not give rise to toxicity problems and which allows high production efficiency with good abrasion properties at low cost, and which further does not lead to emissions in the environment of such significant amounts of pollutants currently emitted by lubrication with the means commonly used commercially.

The present invention relates to an improvement of the methods of forming glass articles, the glass being formed by a full blowing method, the surface of the blank forming the limiting cavity being provided with a layer of a lubricant in the form of a solid film or a glass release agent in the form of a solid film on the surface that limits the cavity and is in contact with the glass. This layer meets the conditions that apply in this area, in that it has the required operating properties so that you get improved efficiency in glass molding at higher quality and lower cost and it greatly minimizes or even eliminates the environmental pollution in the molding areas, which previously arose due to the need for lubrication. The invention thus relates to an improvement of the process for producing glass articles of the type in which mouldable hot glass is formed into a blank or post by contact with a glass-forming, cavity-limiting surface of a glass. hot metal blank, and the blank is then converted into the finished glass article, such as a glass container, by contact with the glass-forming, cavity-limiting surface of a finished mold; the improvement lies mainly in the fact that a layer or film of a solid lubricant or glass release agent is used as the glass-forming or glass-contacting cavity-limiting surface in the substance form of hot metal, the layer consisting of substantially non-colloidal graphite dispersed in a cured organopolysiloxane binder, the graphite being present in an amount sufficient for the layer to have such properties as to release the glass; Instead of forming the blank or post in a blank or post mold by contact with the cavity-limiting metal surface of this mold, this cavity-limiting surface is now provided with and carries a solid lubricant layer.

This layer is formed by applying a dispersion of non-colloidal graphite in an organic solvent of a solvent-soluble, further curable organopolysiloxane to the cavity-limiting metal surface of the mold to provide a cavity-limiting layer, the exposed surface of which is used for contact with the glass in the glass-forming glass. The non-colloidal graphite in question has a size distribution in weight percent, in which substantially all, eg 95% by weight of the particles, are greater than 1 μm in contrast to such colloidal graphite, in which substantially all particles or at least a larger part , such as 50-70%, of the particles by weight are less than 1 μm.

In another embodiment of the invention, in addition to the blank mold with the specified solid layer, the finished mold is similarly provided with a film layer of solid lubricant in the specified manner, the graphite size in the layers of the finished mold not being larger than the size of the graphite. Used for the formation of the layers in the blank form and; preferably the graphite is of such a size that an extremely smooth surface is obtained on the glass object, the graphite size being smaller than the graphite size used in the formation of the layer on the blank form. As generally stated above, the solid layer of the glass lubricant is formed on the blank or finished mold by applying a dispersion of the graphite to an organic solvent solution of curable organopolysiloxane on the metal surface which contacts the glass and limits the cavity in a normal conventional mold or mold. . Conventional methods are advantageously used in the production of the metal surface which delimits the dachshund holes in the blank or finished form which receives the dispersion. This means that according to a preferred. embodiment, the mold surface is prepared by conventional methods of sandblasting and priming. Conventional primers are used in the priming process, such as phosphates, and particularly suitable conventional primers are organosilicon compounds. Examples of satisfactory primers are those set forth in U.S. Pat. No. 3,088,847 as well as those set forth in GB PS 952 992. Suitable primers are: in particular the amino organosilicon compounds listed in GB PS 952 992 in Table I, such as the amino silicon material designated D, as well as combinations of these amino organosilicon compounds with the epoxy compounds disclosed in the patent specification. The application of the graphite dispersion in the organic solvent solution of the curable organopolysiloxane can likewise be done in a conventional manner, such as by rinsing application or spray application. It should be mentioned in passing that when talking about the graphite particle size, the size referred to is the size of the graphite added to the organopolysiloxane solution to form the dispersion. After the dispersion has been applied to the cavity-limiting metal surface in the finished mold and after the evaporation of the solvent, the final curing of the organopolysiloxane takes place to form the solid film of graphite lubricating layers which are dispersed or bound in the cured organopolysiloxane binder and having a surface which is in contact with the glass and limits the cavity. Usually, the thickness of the layer is offset by the solid film of lubricant once formed on the blank form, which layer has the general contour and shape of the former. cavity-limiting metal surface, so that the layer does not become so thick that the film flakes off during use and glass formation and not so thin that the film breaks too soon due to it breaking. It has been found that as a rule a thickness of the final layer of the order of approx. S, oa x 1o'3: in gives ca_a, s9 x 1o "3 thickness between 5.08 x 1o'3 to 1111.62 x 1o'3, c cx approx. 6.35 x 10_3 to 7.62 x 10 -3 cm excellent results for the blank or post form, whereby for the finished form the desired thickness amounts to approx. 2.54 to 5.08 x 10-3 cm, preferably approx. , 54 x 1o'3: in ca 3.81 x 1o'3 cm.

For any general views regarding the formation and application of solid lubricants, please refer to Solid Lubricants by M.E. Campbell, J.B. Loser and E. Sneegas, NASA, Washington, D.C. May 1966, pp. 7-17.

The organopolysiloxanes used are soluble in solvents, curable organopolysiloxanes. These materials are well known and constitute hydrolysis and condensate. This means cm, preferably a ion products of hydrolyzable silanes. that they are hydrolysis and condensation products of silanes by means of hydrolysis groups, such as, for example, halide groups, normally a chloride group, or alkoxide groups, wherein the alkyl moiety of the alkoxide has 1 to about 5 carbon atoms.

Preferred curable, solvent-soluble organopolysiloxanes are organopolysiloxanes, wherein the organo groups are lower alkyl groups, for example (C 1 -C 3) alkyl groups or phenyl groups. These materials can be prepared by hydrolysis and condensation of the respective hydrolyzable silane alone, or they can be hydrolysis condensation products of mixtures of the hydrolysable silanes, or the organopolysiloxanes can simply be 8 mixtures of two or several curable organopolysiloxanes. Suitable organopolysiloxanes are curable, further curable methylphenylsiloxanes. It is well known that these types of additional curable organopolysiloxanes can be described with reference to their R: Si ratio, wherein R represents the number of moles of organic groups directly attached to silicon atoms. According to a preferred embodiment of the invention, the organopolysiloxanes have an R: Si ratio of 11r or more to less than about 2: 1. At ratios above 2: 1, the organopolysiloxanes are normally present as oils and are not of the further-curable, thermosettable type of organopolysiloxane, which is advantageously used according to the invention. Very good results are obtained when using an additional curable, curable organopolysiloxane with an R: Si ratio of about 1: 1 or more up to about 1.6: 1 and particularly good results are obtained with an R: Si ratio between approx. 1: 2: 1 to about 1, 6: 1. As previously stated, the further curable, curable organopolysiloxane according to a preferred embodiment of the invention is methylphenylsiloxane. As can be seen from the above R: Si ratios, these siloxanes can be prepared by hydrolyzing suitable hydrolyzer barasilanes to the desired R: Si ratio. These materials can be obtained, for example, by hydrolysis and condensation of a condensable and hydrolyzable monomer mixture of methyltrichlorosilane, phenyltrichlorosilane and dimethyldichlorosilane.

Alternatively, they can be prepared by hydrolysis and condensation of methyltriethoxysilane, phenyltriethoxysilane and dimethyldiethoxysilane. Of course, as indicated, other alkoxysilanes and other halosilanes can be used as well as mixtures thereof. In addition, as stated above, the R: Si ratio may be 1: 1, which means that the organopolysiloxane may be a lower alkylpolysiloxane, such as, for example, methylpolysiloxane, which is prepared from, for example, methyltrichlorosilane or methyltrialkoxysilanes, 2 g such as methyltoxane organosysilane be a phenylorganopolysiloxane, such as a compound prepared, for example, from phenyltrichlorosilane or a phenyltrialkoxysilane, such as, for example, phenyltriethoxysilane or mixtures thereof.

The organic solvent for the (additional) curable organopolysiloxane used to prepare the solution of the organic solvent, and in which the graphite is dispersed, can be routinely selected by those skilled in the art. Examples of solvents are ethyl alcohol, propyl alcohol, benzene, ethers, ketones, eg acetone, mixtures thereof, mixtures of white spirit, isobutyl acetate and ethylene glycol monomethyl ether, and aromatic solvents such as xylene and toluene. Xylene is particularly good results. The concentration of the (additional) curable organopolysiloxane in the organic solvent is likewise routinely selected by the person skilled in the art and good results are obtained, for example, with a solution of organic solvent of about 10 to about 35% by weight of solid organopolysiloxane and very good results are obtained with a solution of 25 to 35% by weight of organopolysiloxane. A particularly suitable system has about 30% by weight of organopolysiloxane in xylene.

'Dry particulate, non-colloidal gram; mix intimately with the solvent solution to form a graphite dispersion. Advantageously, the weight ratio of graphite to solid organopolysiloxane in the dispersion amounts to about 0.8: 1 to about 2: 1, preferably about 1: 1 to about 2: 1 and excellent results are obtained with a ratio of about 1: 1 to about 1.75. : 1, whereby a ratio of 1.5: 1 is superior. As for the size of the graphite, nânüsas are attached to the attached diagrams, in which the size of different weight contents of graphite (ordinate) is conventionally semi-logarically set aside against particles that are coarser than a prescribed particle diameter (abscissa) in pm. For convenience, the diagram shows as dashed lines the 90% coarser and 10% coarser line of the ordinate, which extends from kunnnza B to F.. 7808334-2 10 15 20 25 30 '35 10 The curves are based on a Coulter Counter size analysis and when in the present text reference is made to the size, a Coulter Counter size analysis is meant. The graphite which is surprisingly and most suitably used in forming the glass-contacting or glass-forming, cavity-limiting surface of the solid film of the lubricant, or the coating on the blank form, is graphite having a size distribution curve, wherein the curve is between 90% coarser and 10%. the coarser part falls within the range which is approximately limited by: (1) curve B, K2) - curve F and (3) the 90% line and (4) the 10% line on the ordinate axis, preferably within the range which is approximately limited of: (l) curve C, (2) curve E, and (3) the 90% line and (4) the 10% line on the ordinate axis. Very distinguished results have been obtained with graphite having a size distribution curve within the area approximately bounded by curve B and curve F, and preferably within the area approximately bounded by curve C and curve E, graphite having a size distribution in the order of magnitude D of the curve is preferred. The stated data generally describe a graphite used in the solid lubricant layer in the film on the blank form. In a preferred embodiment, where the finished mold is also provided with a layer of a solid film of graphite lubricant dispersed in cured organopolysiloxane, the graphite used in the molding of the finished mold layer has a size not exceeding the one used in forming the layer on the blank mold, and preferably the graphite size here is smaller; if, for example, graphite is used for the finished mold with a size disturbance than about curve B, it is desirable to smooth out the surface of the solid film of the lubricating layer by rubbing with greaseproof paper before use.

The dispersion of graphite in the solution of organic solvent with additional curable organopolysiloxane, which dispersion is applied to the cavity-limiting metal surface in the blank or finished form may also include other materials. These materials are, for example, those materials which promote the cure rate of the organopolysiloxane, wherein cure properties are present in an amount sufficient to accelerate the cure. Normally, such curing promoters are present in an amount of less than about 15% by weight based on the solid material organopolysiloxane. The curing promoters used are routinely selected by those skilled in the art and are materials conventionally used for curing organopolysiloxanes. Particularly suitable curing promoters known per se for curing organopolysiloxanes are melamine formaldehyde, a partially condensed resin, which term includes alkylated partially condensed melamine formaldehyde resins. These alkylated melamine formaldehyde resins are those of the melamine formaldehyde type in which alkylation has taken place with carbon monomers or mixtures thereof, such as (C1-C5) -alkyl alcohols. Such a suitable material is supplied by Koppers Chemical Company such as Koprez 70-10 partial condensate resin of butylated melamine formaldehyde.

For example, melamine formaldehyde-type partial condensation resins are used to accelerate curing. of the organopolysiloxane, completely satisfactory results are obtained with between about 0.5 or 1% by weight and about 14 or 15% by weight of the partial condensate resin of melamine formaldehyde based on the organopolysiloxane solids weight. Excellent results are obtained without adversely affecting the wear rates or the glass-forming process is obtained, for example, with about 13% to 14% by weight of partial condensate resin of melamine formaldehyde based on solid organopolysiloxane. Other particularly suitable curing promoters are phosphonic acids, such as the phosphonic acids described in U.S. Pat. No. 3,654,058, with phenylphosphonic acid being particularly preferred in an amount of, for example, about 5% by weight based on the organopolysiloxane. The dispersion may additionally contain conventional additives such as conventional thixotropic agents, which are used to adjust the rheology of the dispersion so as to obtain the flow which is best suited to the manner in which the dispersion is applied. the cavity-limiting metal surface of the mold. Normally these thixotropic agents are present in rather small amounts, i.e. less than 2 or 3% by weight based on solid organopolysiloxane. These thixotropic agents are well known in the art and a suitable material is Thixin R, which is commercially available from Baker Castor Oil Company, which material is a hydrogenated castor oil.

Other suitable thixotropic agents that can be used are, for example, those commercially available from Kelco Company under the name Soloid.

After the dispersion of the graphite in the organopolysiloxane solution has been applied to the cavity-limiting surface of the conventional finished, mold or blank, the solvent is allowed to evaporate and the organopolysiloxane is then heated for a sufficient period of time and at a sufficiently high temperature to obtain a hard cured organopolysiloxane. This results in the formation of the layer or coating having a glass-contacting or glass-forming, cavity-limiting surface which acts as a solid film of lubricant and which layer comprises the graphite dispersed in the cured organopolysiloxane binder. Of course, if a curing promoter or thixotropic agent is used, the binder will also include these materials. Generally, the binder will be in the order of at least about 80% by weight, normally at least about 85% by weight of the cured organopolysiloxane.7 The present invention has now been described in sufficient detail for one skilled in the art to routinely utilize the invention but not nevertheless, several examples will further describe the invention as regards blank forms.

When the following examples refer to the resin 12-630, it refers to a curable organopolysiloxane resin solution (60% by weight solid resin in xylene), wherein the organic groups consist of methyl and phenyl groups, i.e. a methylphenylsiloxane, and wherein the ratio of these groups, i.e. the ratio of methyl and phenyl groups per silicon atom (R: Si ratio) is about 1.4 and wherein the ratio of methyl to phenyl groups on a molar basis is about 3.3: 1, both of these values being based on analysis. In addition, reference is made to various graphites in the examples. The graphite designated 007-S corresponds to the size analysis largely exemplified by curve C, the graphite designated A-98 substantially corresponds to the size analysis designated curve D and the graphite; denoted UC-38 corresponds to the size analysis, denoted by curve E. These curves indicate the mean values of at least two different Coulter Counter size analyzes for each type of graphite.

The Coulter Counter used was type T manufactured and sold by Coulter Electronics Inc .; Conventional techniques were used, using multiple apertures of 400, 14D, 50 and 30 .mu.m and an electrolyte of about 4 g of lithium chloride in 100 ml of a solution of lithium chloride in methanol. Graphite 007-S and A-98 were obtained from Asbury Graphite Mills Inc., and graphite No. 38 was obtained from Union Carbide Chemical Company. These graphites are commonly described as electric furnace graphite or synthetic graphite and are provided as dry particulate matter. Similarly, in the following examples, reference is made to a curing promoter, or catalyst, designated Koprez 70-10. This resin is commercially available from Koppers Chemical Company and it consists of a solution of organic solvent and partial condensate resin of butylated melamine formaldehyde, the resin solids content amounting to about 80% in n-butyl alcohol. 7 In the following examples, the blank molds were prepared using vertically mobile spraying. This means that the divided molds were closed and its cavity-limiting surface was sprayed with a 360 ° nozzle, which was movable vertically. A transport device was arranged, which was driven pneumatically in the vertical direction, and this transport device carried a vertically arranged tubular member, which at its lower end carried a 360 ° nozzle; the cavity of the mold was sprayed by adding the anhydrous dispersion, as described in the examples, to the spray nozzle through the tubular member while the spraying was in progress while the conveyor was pneumatically moving upwards. Prior to spraying, the cavity limiting surfaces in the mold were sandblasted in a conventional manner and then primed with conventional primers. The material used was a material supplied by Union Carbide Corporation under the designation A.P. 132. After curing the organopolysiloxane to a layer of graphite dispersed in the cured organopolysiloxane binder, which layer has a glass-forming or glass-contact cavity-limiting surface, the molds were used as blank molds in a pilot plant with conventional IS machines for forming something commercially available. referred to as GB-121 glass bottles. The I.S. machines used the prepared hot metal molds and the machines worked after the blowing process, but of course the press blowing process is just as satisfactory. This meant that during molding, a moldable hot ice cream batch was formed into a blank or post in a blank or post mold without relative rotation and the blank or post was formed into the finished bottle in a finished mold without relative rotation between the glass and the finished mold. In the examples that follow, the neck rings and bottom plates were not provided with a solid film layer of lubricant, but of course this can be done.

In the examples that follow, wear rates are given as well as the life of the molds. The wear rate is the parameter used to assess the quality of a solid lubricant in film form for the blank form.

The wear rate is expressed as a loss in coating thickness per unit time and is stated in mm / h. The larger the number, the larger the wear. The blank molds were covered and the coating thickness or solid film layer of the lubricant was measured at six points, three on each side of the split mold. The points used were at a distance of 2.54 cm from the top of the cavity, at 10 15 20 25 30 vaoazzu-2 15 2.54 cm from the bottom and at the same points were used when eating thickness measurements are made approximately the middle of the blank shape, after abrasion has taken place through the use of the hot metal mold in the glass-forming process. The coating thickness was measured with a type 7000 magnetic thickness gauge manufactured by H. Tinsley and Company Ltd., London, England. The molds were then installed in the glass forming machine, here an I.S. sheet molding machine, and bottles are made until they are no longer of the desired quality, ie until the mold coating breaks. This occurs at the point where bare metal in the mold is exposed. This exposure normally causes the glass to adhere to the exposed metal surface in the mold, resulting in defects in the glass surface. The blank shape is then removed from the machine and measurements of the coating thickness are made at the same six points. The decrease in coating thickness at each location divided by the time that the mold is used indicates the wear rate at that location. The average of the six abrasion rates at different points on the blank form indicates the abrasion rate of the coating material or the solid film layer of the lubricant for the form in question. The total abrasion rate for the particular film layer of lubricant indicated is calculated by taking the average of the abrasion rates for each individual mold which was covered with the material and which was run in the glass forming machine.

The number of substance forms used with a given coating material was always greater than 2 and normally 4.

The service life of the mold with the solid film layer of lubricant naturally depends on the wear rate and also on the thickness of the layer. A very significant, additional factor in terms of service life is the degree of load uniformity of the moldable glass in the mold.

In order to obtain service lives that can be calculated from the wear rates, it is extremely important that the moldable glass is invested evenly in the mold so that localized wear within an area is excluded. Such localization, of course, gives misleading lifetimes which do not properly represent the properties of the solid lubricant layer, since only a small spot or a small one. area may indicate that the service life has been exceeded, but if even load had been achieved, a significantly higher service life would have been achieved. The service lives given in the examples refer to intervals for the respective molds, where the glass quality has become unsuitable.

EXAMPLE I (A) A dispersion was prepared by intimately mixing about 150 g of xylene, 150 g of a resin solution R-630, 150 g of graphite No. 38 and 15 g of a resin solution of butylated melamine formaldehyde (Koprez 70-10). The dispersion of the graphite in the solution of organic solvent of additional curable ofganopolysiloxane and the added partial condensate resin of butylated melamine formaldehyde were then intimately mixed and sprayed on the metal surface which limits the cavity of the blank forms. After evaporation of the solvent, the system was cured for 1 hour at 343 ° C to effect final curing of the further curable organopolysiloxane resin, and each mold was provided with a layer of the solid lubricant, wherein the graphite was dispersed in the cured binder. Instead of the previous metal surface, this solid layer becomes the glass-forming, cavity-limiting surface in the blank form. The molds were then used as blank molds in an I.S. machine and they showed an average wear rate of about 0.114 and a life of 11 to about 25.5 hours.

(B) The procedure of Examples I-A was essentially repeated, but the butylated melamine formaldehyde resin was omitted and the curing was carried out for 1 hour at about 93 ° C, then for 1 hour at 260 ° C and 2 hours at 316 ° C. When the substance forms were evaluated on the I.S. machine, it was found that an increase rate of about 0.121 and a life of cszz 11111 about 33.5 hours were obtained.

(C) The procedure of A was repeated but a new mass of R-630 resin was used and had a lower viscosity. This gave an enzyme rate of about 0.085 and a life of about 26 to about 29 hours. EXAMPLE II (D) The procedure of Example 1B was mainly repeated but instead of graphite # 38 was used. graphite A-98, the weight ratio of graphite to organopolysiloxane solid being substantially the same, i.e. a weight ratio of about 1.5: 1 and about 0.8 g of Thixin R, a well known thixotropic agent manufactured by Baker Castor Oil. Company, was also used. The molds had an average wear rate of about 0.083 and a life in the pilot plant of about 24 to about 27.5 hours.

(E) The procedure of Example IA was mainly repeated, but instead of graphite No. 38 graphite Ar98 was used in a weight ratio of about 1.5: 1 graphite to organopolysiloxane and the dispersion contained 0 {8 g of Thixin R. The wear rate of these molds was about 0.072 and the pilot plant had a service life of 12 to 32 hours.

(F) The procedure of Examples II-E was repeated on another occasion and the molds showed a wear rate of 0.068 and a life in a pilot plant of 22 to 27 hours.

(G) The procedure of Example II-F above was largely repeated but the amount of butylated melamine formaldehyde material was reduced by a factor of 10, i.e. Example II-F was followed and the indicated graphite A-98 was used, but the amount of butylated melamine formaldehyde resin solution was instead 15 g about 1.5 g. These molds exhibited an average wear rate of 0.106 and had a life in a pilot plant of 13 to about 26.5 hours.

EXAMPLE III '.

(H) The procedure of Examples II-E was repeated, having the same weight ratio of graphite to organopolysiloxane solid, but graphite 007-S was used instead of graphite A-98. These molds showed an average wear rate of 0.1105 and had a pilot plant life of about 14.5 to about 19.75 hours. EXAMPLE IV The procedure of Examples II-E, where an average wear rate of 0.072 was obtained, was repeated, but instead of using a weight ratio of graphite to organopolysiloxane of 1.5: 1, the weight was varied. - -holding. Runs in which the weight ratio was about 1: 1 showed a wear rate of 0.116 and a service life in a pilot plant of 15 to 22.5 hours. Runs in which the weight ratio of graphite to organopolysiloxane solid was about 1.75: 1 showed a wear rate of about 0.105 and the lifespan was about 25.25 to about 30.5 hours.

This shows the unexpected advantage of using a weight ratio of graphite to organopolysiloxane solids of about 1.5: 1.

EXAMPLE V (If A curable organopolysiloxane, wherein the organic groups were methyl and phenyl groups and wherein the ratio of methyl groups to phenyl groups was about 3.6: 1 and wherein the molar ratio of the organic groups, i.e. the phenyl groups and the methyl groups to the silicon atoms f (R: Si The ratio) was about 1.4, was prepared by charging about 2.98 moles of dimethyldiethoxysilane, about 2.31 moles of methyltriethoxysilane and 2.27 moles of phenyltriethoxysilane, this mixture was added with about 19.7 moles of water and then with This mixture was heated to reflux and kept at this temperature for about 4 hours. Before the reflux was achieved, the two-phase system was clarified to a single phase, then the solution was concentrated by removing some ethanol by-product and water by distillation and then further heating to harden the resin without gelation. This method is generally disclosed in U.S. Pat. No. 3,389,121. Xylene was added to form a solution which contained about 80% of organopolysiloxane resin solid. With the addition of this xylene and using a Dean-Starke trap, the system was refluxed for about 4 hours, removing water through the Dean-Starke trap throughout this period. The curable organopolysiloxane solution was then cooled to room temperature and diluted with additional xylene to a solution of about 60% by weight of organopolysiloxane solid.

The procedure of Examples II-E was then repeated largely using the same batch but this organopolysiloxane resin solution was used instead of the resin solution R-630, and only about 90 g of additional xylene was added; this means that 150 g of this resin solution (containing about 60% additional curable organopolysiloxane solid and about 40% xylene) was used instead of the 150 g of R-630 and instead of the 150 g of additional xylene about 90 g was used. molds and cured. The blank molds had a wear rate of about 0.092.

The viscosity of the dispersion used in the spraying was in the order of about 550 to 600 cP.

The same spray solution was diluted with additional xylene to a viscosity of the order of about 250 to 270 cP.

The molds were heated to cure the organopolysiloxane.

These molds showed a ning rate of about 0.070.

The life expectancies obtained are 16 to about 31 hours and about 19 to about 31.7 hours, respectively.

(J) Process II-E was repeated but the 60% organopolysiloxane solution prepared in Example VI was used in place of the solution Rr630 and the amount of butylated melamine formaldehyde resin solution was reduced from 15 g to about 1.5 g. cavity limiting solid film of lubricant showed an abrasion rate of about 0.077 and a life in a pilot plant of about 12.5 to about 23.75 hours.

(K) On another occasion, a 60% organopolysiloxane solution, prepared in the manner described in VI, was used with the preparation of Examples II-E (but this solution was used instead of solution R-630). . An abrasion rate of about 0.059 was obtained with a life in the pilot plant of about 19 to about 46 hours. Acheson Colloidal Company in the form of a dispersion of colloidal graphite to Q0%) in isopropyl alcohol (80% by weight)] distribution is given as curve A in the accompanying drawing. The Coulter Counter size dispersion of the spray was prepared by intimately mixing about ISO g of the R-630 solution, 675 g of colloidal graphite No. 155 (weight ratio of graphite solid to organopolysiloxane solid of about 1.5: 1) and 15 g of Koprez solution. 70-10, the dispersion having a viscosity of about 560 cP at 25 ° C. Several sprays were made and the thickness of the finished layer of graphite bound in the cured organopolysiloxane was about 6.6 x 10-3 to 6.9 x 10-3 cm.

The curing was carried out at about 343 ° C for about 1 hour. The use of these blanks with colloidal graphite showed an average wear rate of 0.210 and a service life of about 8 to about 12 hours. It can be noted that the wear rate is significantly higher than the wear rate. velocity obtained when forming glass objects into blank molds using the present system.

It is thus recognized that serious economic difficulties arise in relation to the frequency of shape changes if one were to use a colloidal graphite system.

EXAMPLE VII The general procedure of Examples II-E was repeated but instead of using graphite A-98 the dispersion was prepared by mixing 20% by weight of the graphite 007-S used in Example IIÉ and about 80% by weight of the graphite A -98, which was used in Examples II-D. The molds for this experiment exhibited a wear rate of about 0.102 and a life of about 17.5 to about 26 hours.

EXEHEL VIII (L) In a similar manner as above, a commercially available curable organopolysiloxane resin was obtained from Dow çorning Company. The particular material used was designated Dow 805. This material is a 50% solution (by weight) of an additional curable organopolysiloxane in toluene. About 360 g of this solution, about 270 g of graphite A-98, about 220 g of xylene, about 36 g of butylated melamine formaldehyde solution (Koprez 70-10) and about 1.6 g of Thixin R were mixed intimately and to form a sprayable disperser. - sion. This dispersion was then applied to the void-limiting surface of the blank molds and cured for about 1 hour at about 650 ° C to obtain blank molds with a glass-forming, void-limiting layer of graphite bonded in cured organopolysiloxane. A wear rate of about 0.088 and a life in the order of about 24 to about 31 hours were obtained.

(M) In a similar manner to Example VIII-L, an additional curable organopolysiloxane used by General Electric Company under the designation SR-240 was used. This material is also supplied as a 50% (wt%) solution of a curable organopolysiloxane in toluene.

The materials were combined in the same proportions as in Example VIII-L using, of course, the SR-240 solution instead of Dow 805. The resulting dispersion had a viscosity of about 1260 cP at about 25 ° C. The molds with the lubricant in the form of a solid film obtained by this system showed an abrasion rate of about 0.122 and a life in the order of about 16.75 to about 22 hours.

(N) A solvent-soluble additional curable pre-cured organopolysiloxane was prepared according to the method of U.S. Pat. No. 3,389,121, using a condensation monomer mixture of methyltriethoxysilane and phenyltriethoxysilane with a ratio of phenyltriethoxysilane to methyltriethoxysilane on ca 4: 4. This material had an R: si ratio of about 1: 1 and a ratio of methyl components to phenyl components in the order of -0.25: 1. This resin was then dissolved in xylene, using 90 g of additional curable organopolysiloxane and 60 g of xylene to prepare a solution. This solution was then used in the manner set forth in Examples II-E to provide a layer of a solid film of lubricant on the molds. The molds exhibited an average wear rate of 0.102 and a life in the order of about 15 to about 18.75 hours. (0) Similarly, a resin was prepared according to the method of U.S. Pat. No. 3,389,212 to produce a curable, precured organopolysiloxane using a monomer condensation mixture. of about 4 moles of phenyltriethoxysilane, 1 mole of methyltriethoxysilane and about 0.5 moles of dimethyldiethoxysilane. This composition had a RsSi ratio of about 1.09: 1 and a ratio of methyl components to phenyl components in the order of about 0.5: 1. This material was transferred to a solution by dissolving about 90 g of the additional curable organopolysiloxane and 60 g of xylene. This solution was then used in place of solution No. R-630 of Example II-E to form a layer of graphite bound or dispersed in the cured organopolysiloxane. The molds with this layer had an abrasion rate of about 0.083 and a life of about 16.5 to about 19.5 hours. '(P) The method of U.S. Pat. No. 3,389,114 was followed to prepare an additional curable, hardened organopolysiloxane using only methyltriethoxysilane as a condensable monomer. About 90 g of this curable, further curable solvent-soluble organopolysiloxane was intimately mixed with about 210 g of xylene and about 32 g of isopropyl alcohol together with 135 g of graphite A-98 and about 15 g of butylated melamine formaldehyde solution (Koprez 70-10) and about 0 g. .8 g (Thixin R) material. The organopolysiloxane prepared in this way had an R: Si ratio of about 1: 1. This dispersion had a viscosity of about 140 cP and was applied to the cavity limiting surface of the blank molds to form a layer of the lubricant. The curing was carried out for about 1 hour at about 343 ° C. The average wear rate of these molds was in the order of 0.085 and the life in the order of 9 to about 18.5 hours. EXAMPLE IX The procedure generally set forth above for Examples II-E was repeated for concerns the production and production of blank molds with a glass-forming, cavity-limiting layer of lubricant. In addition, a finished mold was prepared in substantially the same manner, but instead of graphite A-98 in the dispersion applied, graphite manufactured and supplied by Joe Dixon Company under the designation 200-42 was used, which graphite has a Coulter Counter size distribution which roughly corresponds to the curve B. The only modification of the finished mold is thus that a graphite is used, with a size which was not larger than that used for the blank shape but preferably smaller. When the IS machine was run, excellent results were obtained in terms of the wear rate of the blank molds and a smooth, high-quality surface of the obtained glass object was obtained in the finished mold. The above generally shows the unexpected advantage of the present invention over colloidal graphite, and it can be seen that significantly lower wear rates on the blanks, eg 0, 125 and less, have been obtained with the present invention.

In view of the above, it can generally be stated that the thickness of the final solid film layer of the lubricant, which, as will be seen, represents graphite bound in a cured organopolysiloxane binder and which, as stated above, may additionally include a curing promoter, such as the stated butylated melamine formaldehyde resin and any suitable additives, such as a thixotropic agent, in which the order of magnitude is 15.6 x 10-3 to about 7.1 x 10-3 cm.

When spraying the dispersion to get the material on the mold, which is then cured, it has further been found that the best results are obtained if the spraying takes place under certain conditions; this means that the spraying with the dispersion, when it is applied to the limitation-limiting surface of the mold, must be adjusted in such a way that the evaporation of the solvent before the dispersion arrives. In contact with the mold surface is not so strong that only solid material abuts the mold surface being sprayed, but still the spray should not be so wet that the dispersion, when it strikes the mold surface, runs off due to too much solvent being present.

In the text and examples given and in the requirements that follow, in the case of graphite size, the dry, particulate graphite which is initially used, ie the graphite which is added to form the dispersion, which is then applied to the cavity limiting surface of the mold. When the requirements refer to different curves and the roughness lines 90% and 10%, this refers to the lines specified in the attached diagrams, which are thereby included in the requirements.

Claims (2)

A method for forming a glass article, wherein moldable hot glass is formed into a blank by contact with a cavity-limiting surface of a blank metal blank and then the blank is formed into the article. by contact with a glass-forming, cavity-limiting surface of a finished mold, the formation of the blank and the formation of the object taking place without relative rotation of the glass and the molds, and wherein at least one of the glass-forming, cavity-limiting surfaces is constituted by a solid layer which comprises a solid butter dispersed in an organopolysiloxane binder, characterized in that the limitation-limiting surface 'in the substance form supports the solid layer and that the layer consists essentially of non-colloidal graphite, which is present in sufficient amount for the layer to release glass, an organopolysiloxane and up to 15% by weight, based on the organopolysiloxane, of a siloxane curing promoter. 2. A method according to claim 1, characterized in that the graphite used in the solid layer has a size distribution curve, in which the curve part between about 90% and about 10% falls within the range which is approximately limited by the curves B and F and the ordinance 90% and 10% coarser lines on the accompanying diagrams and that the binder consists essentially of the product obtained by curing organopolysiloxane in the presence of an effective curing promoting amount of siloxane curing promoter. , characterized in that the glass-forming, shelf-limiting surface of the finished mold also carries a solid layer, the size distribution of the graphite in this latter layer being less than the size distribution of the graph used in the layer on the blank mold. 4. A method according to claim 2, characterized in that the graphite has a size distribution within the vanessa-z 46 10 l5 20 25 30 35 area which is approximately limited by curve C and curve E. 5. A method according to claim 1, thereof. , that the graphite has a particle size distribution within the range which is approximately limited by the curve B and the curve F, the solid layer having an abrasion speed of less than about 0.003 mm / h. Method according to claim 2) in that the area is approximately defined by the curves C and E and the coarser lines 90% and 10%. A process according to claim 2, wherein the weight ratio of graphite to organopolysiloxane is about 0.8: 1 to 2: 1. The method of claim 7, wherein the ratio is about 1: 1 to about 1.75: 1. A method according to any one of the preceding claims, characterized in that the curing promoter of a melamine formaldehyde partial condensate resin. k ä n n is lQ. It contains an alkylated melamine formaldehyde resin. ll. Process according to any one of the preceding claims, characterized in that the organopolysiloxane Process according to any one of the preceding claims, in that the resin consists of k a denotes silicon-bonded organic components. an R: Si ratio between 1: 1 and 2: 1, wherein R 12. A process according to any one of the preceding claims, characterized in that the organopolysiloxane is methylphenylsiloxane having an R: Si ratio of about 1.6: l or less. A mold for carrying out the process according to any one of the preceding claims, in which form a glass-forming, cavity-limiting surface is constituted by a solid layer comprising a solid lubricant which is disyrated in an organopolysiloxane binder, characterized in that the solid layer consists essentially of non-colloidal graphite, which is present in a sufficient amount to release the glass, an organopolysiloxane and up to 15% by weight based on the organopolysiloxane, of a hallmarked siloxane curing promo. . 14. A mold according to claim 13, characterized in that the layer of graphite is dispersed in a cured organopolysiloxane binder, and that the layer has a thickness of about 0.005 to about 0.008 cm.