JP2010228999A - Heat-resistant release coating agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-resistant release coating agent capable of performing e.g. glass molding at a low cost. <P>SOLUTION: In a glass molding method, glass is molded by using a mold 10. First, a liquid curable release coating agent is applied to the mold 10 (step S30). Then, the release coating agent applied to the mold is dried (step S40). When dried, the release agent forms a film. Next, molten glass is poured into the mold to which the release agent is applied, and after the molten glass is solidified, the solidified glass is removed from the mold 10 (step S60), Thus, the production (glass molding) of a glass article is performed. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a release coating agent used when molding glass or plastic using a mold.

  When molding glass, a metal mold is used. Before using the mold, a lubricant such as mineral oil is applied to the surface of the mold as a mold release agent. Mineral oil, etc. is excellent in diffusibility, so it is easy to fit on the surface of a metal mold and is relatively easy to apply. And a glass of a bottle shape can be formed by pouring molten glass into a mold coated with mineral oil or the like, providing a hollow portion inside the molten glass, and curing in that state.

  However, mineral oil and the like have low durability because they are not curable. Possible causes of low durability such as mineral oil are deterioration due to heat of molten glass and transfer when the prepared glass is removed from the mold. In order to eliminate these causes, it is necessary to reapply a non-hardening release agent such as mineral oil every time the mold is used. For this reason, the cost of the mold release agent and the cost for applying the mold release agent are incurred, leading to an increase in the cost at the time of glass forming.

For example, Japanese Patent Laid-Open No. 6-15406 discloses that release agent particles made of a porous synthetic silicate compound having a specific surface area of 40 m ² / g or more are suspended in water containing a dispersant. A mold casting release agent is disclosed.

JP-A-6-15406

  However, with the release agent disclosed in JP-A-6-15406, it is necessary to reapply the release agent every time the mold is used. For this reason, there is a problem that the work is not only costly but also difficult.

  Accordingly, an object of the present invention is to provide a heat-resistant release coating agent that can reduce the frequency of applying a release agent or achieve zero (no oil coating) and perform glass molding at a low cost. And

  The present invention basically relates to a release coating agent. More specifically, the present invention relates to a heat-resistant release coating agent containing a silicon compound and alcohol. And when a mold release coating agent is 100 weight part, the weight of a silicon compound is 10 to 40 weight%. In this release coating agent, the alcohol is dried by heating. By the heating, the silicon compound is polymerized to form a film containing a siloxane bond on the surface of the substrate on which the release coating agent is applied. This film has not only high hardness and heat resistance, but also low transferability due to the wide spread of siloxane bonds. For this reason, it is possible to reduce the frequency of applying the release agent or zero (no oil coating).

  The release coating agent preferably contains acetic acid as a surfactant. Thereby, the mold release property of a manufacturing object (glass, plastic) can be improved.

  Further, the release coating agent preferably further contains zirconia. In this case, the weight ratio of the silicon compound and zirconia is 2: 1 or more and 6: 1 or less. The zirconia is uniformly dispersed in the film containing siloxane bonds as the release coating agent is dried. Here, zirconia functions as a component that enhances heat resistance. In this way, heat resistance can be imparted uniformly.

  The alcohol preferably contains isopropanol or ethanol. Thereby, it can be easily dried.

  According to the release coating agent of the present invention, the frequency of applying the release coating agent can be low, and glass molding or the like can be performed at low cost.

FIG. 1 is a process diagram (flow chart) schematically showing the procedure of the glass forming method of the present invention. FIG. 2 is a diagram schematically showing a configuration of an example of the mold created in step S10 of FIG. 1, FIG. 2 (a) is an exploded perspective view of the mold, and FIG. 2 (b) is a mold. It is an upper side figure of one mold piece which constitutes. FIG. 3 is a diagram used for explaining a state when gobing is performed when producing a glass product in step S60 of FIG.

  Hereinafter, the release coating agent of the present invention will be described. The release coating agent is liquid and exhibits curability when dried. Therefore, the release coating agent is different from a lubricant (release agent) that does not have curability like mineral oil. The release coating agent may be a powder raw material diluted with a liquid. The release coating agent may be aqueous or oily. As such a release coating agent, it is possible to use a powder raw material containing a silicon compound and an alcohol containing alcohol as a liquid dispersion medium for dispersing the powder raw material.

  And when a mold release coating agent is 100 weight part, the weight of a silicon compound is 10 to 40 weight%. In this release coating agent, the alcohol is dried by heating. By the heating, the silicon compound is polymerized to form a film containing a siloxane bond on the surface of the substrate on which the release coating agent is applied. This film has not only high hardness and heat resistance, but also low transferability due to the wide spread of siloxane bonds. For this reason, it is possible to reduce the frequency of applying the release agent or zero (no oil coating).

  The release coating agent preferably contains acetic acid as a surfactant. Thereby, the mold release property of a manufacturing object (glass, plastic) can be improved.

Further, the release coating agent preferably further contains zirconia (ZrO ₂ ). In this case, the weight ratio of the silicon compound and zirconia is 2: 1 or more and 6: 1 or less. The zirconia is uniformly dispersed in the film containing siloxane bonds as the release coating agent is dried. Here, zirconia functions as a component that enhances heat resistance. In this way, heat resistance can be imparted uniformly. Here, when the weight ratio of zirconia to the silicon compound is increased, the polymerization of the silicon compound is easily inhibited, and when the weight ratio is decreased, the heat resistance cannot be sufficiently increased. Therefore, the weight ratio of the silicon compound and zirconia may be from 3: 2 to 4: 1.

  The alcohol preferably contains isopropanol or ethanol. Thereby, it can be easily dried.

The silicon compound as a powder raw material matches the main component of the glass to be produced. For this reason, the coating film by the siloxane bond produced | generated by the silicon compound and its polymerization functions as a component which improves the affinity with glass in a release coating agent. By increasing the affinity, the molten glass spreads evenly on the surface of the mold 10 and the produced glass is less likely to wrinkle. However, if the content of the silicon compound is too large, the affinity becomes too high, and the release coating agent is easily detached from the mold surface, and as a result, the possibility of being transferred to the produced glass is increased. Therefore, it is preferable that the upper limit value of the silicon compound content is 90% by weight in terms of the proportion of the powder raw material. On the other hand, the coating film made of a silicon compound and a siloxane bond functions as a heat insulating material because it prevents direct contact between the mold 10 and the molten glass. Thereby, deterioration, such as a deformation | transformation of the casting_mold | template 10, can be suppressed. In order for the coating film made of a silicon compound and a siloxane bond to function as a heat insulating material, the lower limit of the content of the silicon compound is preferably 20% by weight in the proportion of the powder raw material.
An example of a silicon compound is a disilanol compound. It is known that a disilanol compound is polymerized by heat to form a siloxane bond. The silicon compound is not limited to the disilanol compound, and any compound may be used as long as it forms a siloxane bond by polymerization. Further, it may be polymerized by light. Moreover, what polymerizes with a catalyst may be sufficient, and a catalyst is contained as a powder raw material in this case.

  Zirconia is a component that improves the heat resistance of the mold 10. By improving the heat resistance, deterioration such as deformation of the mold 10 can be suppressed. In addition, zirconia has a lower affinity for glass than a coating made of a silicon compound and a siloxane bond. For this reason, the release coating agent contains zirconia, so that the affinity of the film due to the silicon compound and the siloxane bond can be lowered moderately, the release property of the glass can be improved, and the heat resistance of the mold 10 is improved. be able to. The content of zirconia is appropriately set according to the content of the silicon compound contained in the release coating agent and the temperature of the molten glass.

The release coating agent may contain titanium dioxide (TiO ₂ ), iron (III) oxide (Fe ₂ O ₃ ), zircon (ZrSiO ₄ ) as a powder raw material. These components also have a function of appropriately reducing the affinity of the coating film due to the silicon compound and the siloxane bond and improving the releasability.

  In this embodiment, alcohol is used as a dispersion medium for dispersing the powder raw material as described above. Alcohol includes not only pure alcohol but also a mixture of alcohol and water. Examples of alcohols are isopropanol or ethanol. As the alcohol, volatile ones are used, for example, isopropanol or ethanol is used. Thereby, the volatility of the liquid component in the release coating agent can be increased, and the drying time in the drying step described later can be shortened. Moreover, as alcohol, what can maintain a dispersed state over a long period without the powder raw material mentioned above precipitating is preferable. Moreover, water may be used as a dispersion medium, and further, it may be used by mixing with the above alcohol or the like.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the form described below is an example, and can be appropriately modified within a range obvious to those skilled in the art.

  FIG. 1 is a process diagram (flow chart) schematically showing the procedure of the glass forming method of the present invention. In this embodiment, a case where a glass bottle is manufactured by molding glass will be described.

  In FIG. 1, first, in step S10 of FIG. 1, a mold 10 used for glass forming is created. In this embodiment, a metal is mainly used as a constituent material of the mold 10. The metal may be a simple substance or an alloy.

  2 (a) and 2 (b) are diagrams schematically showing the configuration of the mold created in step S10 of FIG. 1, and FIG. 2 (a) is an exploded perspective view of the mold. 2 (b) is a top view of one mold piece constituting the mold.

  As shown in FIG. 2A, the mold 10 has a hollow portion 11 having a shape complementary to the outer shape of the glass bottle to be manufactured. The surface facing the hollow portion 11 of the mold becomes a grounding surface (molten glass grounding surface) 12 when molten glass is poured.

  Further, as shown in FIG. 2A, the mold 10 is cut into two along the longitudinal direction, and is configured to be a pair of mold pieces 10a and 10b. The cut surface of each mold piece 10a, 10b becomes a grounding surface (mold piece grounding surface) 13 with which the other mold piece comes into contact during glass molding. Here, of the pair of mold pieces 10a and 10b, a protrusion is provided on the mold piece grounding surface 13 of one mold piece, and the mold piece grounding surface 13 of the other mold piece is complementary to the outer shape of the protrusion. It is preferable to provide a fitting groove having an outer shape that forms an arbitrary shape. Thereby, it becomes easy to make the external shape of a glass bottle and the external shape of the hollow part 11 of a casting_mold | template correspond by making one casting_mold | template piece and the other casting_mold | template piece face each other. In addition, what is provided in the casting_mold | template piece grounding surface 13 of a casting_mold | template piece is not restricted to a protrusion-fitting groove, What kind of thing may be sufficient if it is a process which has an equivalent function.

  In this embodiment, the shape of the hollow portion 11 provided in the mold 10 is substantially cylindrical as shown in FIG. 2B, and the bottom of the cylinder is a corner of the glass bottle that is the object of manufacture. In addition, the top of the cylinder has a narrow width and becomes the head (mouth) of the glass bottle.

  Subsequently, in step S20, the mold 10 created in step S10 is washed. There are first to third cleaning methods for cleaning the mold 10.

  In the first cleaning method, the mold 10 is immersed in a cleaning solution. Specifically, the oil adhering to the prepared mold 10 is separated from the surface of the mold 10 by the cleaning component of the cleaning liquid, the oil itself is decomposed, and the dust adhering to the surface of the mold 10. Etc. are diffused into the solvent of the washing solution.

  The second cleaning method is to perform electrolytic cleaning on the mold 10. Specifically, the mold 10 is immersed in an electrolytic solution, and electric power is applied to the mold 10 or the electrolytic solution, whereby dust and impurities attached to the mold 10 are decomposed by electric energy, Or leave.

  The third cleaning method applies ultrasonic waves to the mold 10. Specifically, by immersing the mold 10 in water or the like and irradiating the mold 10 with ultrasonic waves, dust and impurities adhering to the mold 10 are generated by ultrasonic collision energy and ultrasonic waves. It is decomposed or detached from the surface by vibration energy. In addition, when applying an ultrasonic wave, instead of immersing the mold 10 in water, the mold 10 may be immersed in a cleaning solution.

  The first to third cleaning methods described above can also be executed in combination. For example, after the template 10 is cleaned by the first cleaning method, the template 10 is further cleaned by the second cleaning method. The selection of the cleaning method and the cleaning procedure may be performed according to the degree of contamination of the mold 10. By adopting two or more cleaning methods, dust attached to the mold 10 can be more reliably removed. Moreover, it is preferable to wash out the surface of the casting_mold | template 10 with high-clarity water etc. as needed.

  Then, after the cleaning of the mold 10 is completed, the mold 10 is dried (step S30). As a result, rust is less likely to occur in the mold 10 and dust is less likely to reattach.

  Thereafter, a release coating agent is applied to the mold 10 (step S40). The release coating agent is applied to at least all surfaces (molten glass ground surface 12) where the molten glass is grounded. Furthermore, it is preferable to apply also to the mold piece grounding surface 13, whereby the wear due to the contact between the mold pieces and consequently the displacement caused by the contact can be suppressed.

  Subsequently, the release coating agent applied to the mold 10 is dried (step S50). Specifically, the alcohol and water contained in the release coating agent are volatilized. The drying at this time may be natural drying, air drying, or drying by heating. In addition, since this drying step (S50) is only a pretreatment of the following baking step (S60), it is not necessary to volatilize alcohol and water completely in this treatment.

  Then, a printing step (S60) is performed. In this baking step, the mold 10 coated with the release coating agent is positively heated. Thereby, the dispersion medium contained in the release coating agent is almost completely evaporated, and the release coating agent is surely dried. As a result, the powder raw material uniformly dispersed in the dispersion medium is fixed on the surface of the mold 10 in a state reflecting the dispersion state. Thereby, the mold 10 without temperature unevenness is created. The film thickness of the release coating agent after the baking treatment varies depending on the composition of the release coating agent, but is substantially constant between 5 μm and 40 μm. Thus, since the film thickness of the release coating agent is very small, it is not necessary to change the dimensions of the mold 10 in accordance with the film thickness of the release coating agent.

  Here, the baking method will be described. Examples of the baking method include a method using a far infrared heater (first baking method) and a method using a burner (second baking method).

  In the first baking method, for example, far infrared rays from a far infrared heater are irradiated for 30 minutes to 60 minutes toward the surface of the mold 10 on which the release coating agent is applied. The irradiation time is appropriately changed according to the surface area of the mold 10, the application amount of the release coating agent, and the film thickness. In the second baking method, the flame of the burner is directly applied to the surface of the mold 10 on which the release coating agent is applied. In other words, apply a direct fire. As a result, in the part where the flame is approaching, it is heated locally and the dispersion medium is surely volatilized. In addition, the time to apply the direct fire is adjusted so that the solid component of the release coating agent does not elute or burn. In addition, when the alcohol contained in the release coating agent has high flammability, it is preferable to use a far infrared heater.

  In the baking step of this aspect, baking is performed by the first baking method as the first baking process, and baking is performed by the second baking method as the second baking process. By performing the baking process twice in this manner, the dispersion medium is surely evaporated, and the release coating agent is further reliably dried. As long as the dispersion medium can be evaporated, any baking method may be used, baking may be performed only by the first baking method, or baking may be performed only by the second baking method.

  As described above, by performing the processes in steps S10 to S50, the mold 10 necessary for manufacturing the glass product is prepared. In addition, what is necessary is just to perform the process of step S20-S50, when using the casting_mold | template 10 which has already been used for production of glass products.

  Then, a glass product is produced using the prepared mold 10 (step S60). In the production of glass products (that is, glass molding), first, molten glass (gob) 20 is poured into the hollow portion 11 of the prepared mold 10 as shown in FIG. The gob-filled molten glass is pressed so as to match the shape of the hollow portion 11 of the mold 10, and finally, the molten glass is cooled or allowed to cool naturally in the pressed state. As a result, the molten glass is solidified. That is, the glass can be formed so as to have the outer shape of the glass product to be manufactured. And if molten glass solidifies, the solidified molten glass will be removed from the casting_mold | template 10, and it will be set as a glass product. In this embodiment, a glass bottle is manufactured as a glass product. Therefore, after gobing the molten glass, a gas such as air is sent and inflated toward the center of the molten glass. As a result, the hollow part of the glass bottle is formed and pressed.

  After the production of the glass product is completed, the quality of the glass product is checked (step S70). Quality check items include internal pressure strength, mechanical impact strength, running impact strength, vertical load strength, thermal shock strength, and analysis of wall thickness distribution. As a result of the quality check, the glass product whose glass product quality is bad is discarded. Normally, this quality check is performed for each lot (after producing a plurality of glass products). Therefore, before the quality check, the production of the glass product in step S60 is performed a plurality of times.

  And as a result of the quality check, when the quality of the glass product is often worse than the predetermined quality (when the yield is bad or the discard rate is high), the process returns to step S10 or step S30. Then, the release coating agent is applied again to the mold 10.

  On the other hand, if the quality of the glass product is equal to or superior to the predetermined quality (if the yield is good or the discard rate is low), the process returns to step S60 to return to the glass product. Will continue production. That is, in this case, it is not necessary to reapply the release coating agent to the mold 10.

  As described in detail above, in this embodiment, instead of a release agent that does not have curability, a curable release coating agent that cures by drying is adopted, and the above-described steps are sequentially executed. Thus, the release coating agent applied to the mold 10 is sufficiently dried. As a result, the cured release coating agent has high durability. Therefore, the frequency of re-applying the release coating agent can be very low. Specifically, as will be described in the examples described later, according to this aspect, compared with a case where a release agent that does not have curability is employed, or when any of the above steps is omitted. Even so, the frequency of re-applying the release coating agent is very low. Thereby, glass molding (production of glass products) can be performed at low cost.

  Moreover, in the said aspect, although water and alcohol were illustrated as a solvent in a mold release coating agent, you may use organic solvents (thinners), such as butyl acetate. In this case, as the organic solvent, one that is dried by baking treatment and has low flammability is selectively used.

  Moreover, in the said aspect, although the release coating agent apply | coated to the casting_mold | template 10 was baked by step S50 of FIG. 1, it does not need to perform. In this case, it is preferable to sufficiently dry the release coating agent applied to the mold 10 in step S40.

  Furthermore, in the above aspect, it is preferable to apply the release coating agent a plurality of times by repeatedly performing the processes of steps S40 to S50 in FIG. Thereby, the casting_mold | template 10 with which the mold release coating agent was uniformly apply | coated can be prepared. However, if the release coating agent is applied a plurality of times, the film thickness may increase and the mold 10 may need to be resized. Therefore, it is more preferable that the number of times of application of the release coating agent is 3 at the maximum.

  Further, in the mold 10 used for the production of the glass product, there is a possibility that unevenness is caused due to deterioration or transfer of the applied release coating agent. In this case, the processing of steps S40 to S50 in FIG. 1 is performed (the processing of steps S20 to 30 is also performed as necessary), so that the unevenness of the release coating agent that has occurred can be repaired. is there. That is, according to this aspect, it is easy to reuse the mold 10.

  Next, examples of the present invention will be described. In the embodiment, as described in the above embodiment, the above-described release coating agent is adopted, and when the above-described steps are sequentially executed (Example 1), conventional mineral oil is adopted as the release coating agent. In addition, the case where the glass product was manufactured by the conventional method (Comparative Example 1) was compared. Further, the case of Example 1 where the conditions were changed (Examples 2 to 4) was also compared.

  In Example 1, the release coating agent A was adopted as the release coating agent. The composition of the release coating agent A was 16% by weight of the silicon compound, 5% by weight of zirconia, 60% by weight of isopropanol, and 19% by weight of ethanol. This release coating agent A is liquid and aqueous, and exhibits curability when dried. And the glass product was produced according to the procedure shown in FIG.

  In Example 1, even when the production of the glass product was continued for 19 hours, and in some cases for 24 hours, it was not necessary to reapply the release coating agent A.

  Further, for the mold 10 of Example 1, it was examined whether or not temperature unevenness occurred on the surface after the release coating agent was applied. Specifically, a thermal image was taken when the mold 10 was heated, and the obtained thermal image was analyzed. As a result of this analysis, it was found that in the mold 10 to which the release coating agent A was applied, the temperature difference was very small on the surface on which the release coating agent A was applied. That is, it was found that the release coating agent A was uniformly applied without unevenness. This result shows that one example of the reason why the discard rate of the glass product did not increase in Example 1 was that the molten glass was uniformly cooled by applying the release coating agent evenly. It shows that it can be mentioned.

  In Example 1, the case where the composition and components of the release coating agent were changed within the range described in the above embodiment was also examined. In this case, although the time during which the glass product can be continuously produced is different, the frequency of re-application of the release coating agent is lower in this case as compared with the case of Comparative Example 1. I understood.

(Comparative Example 1)
In Comparative Example 1, an oily mineral oil was employed as a release agent having no curability. Since this mineral oil has flammability, the procedure shown in FIG. 1, in particular, the quenching step (S50) cannot be adopted. Therefore, in Comparative Example 1, as in the conventional case, the mineral oil was applied to the mold 10 and the glass product was produced without drying. However, the same mold 10 as in Example 1 was prepared.

  And in this comparative example 1, when producing glass products in multiple times, it turned out that a discard rate becomes high. Therefore, when the mold 10 after the production of the glass product was repeated a plurality of times, it was found that no mineral oil remained on the surface of the mold 10. This is thought to be the result of being transferred to a glass product. Therefore, it was found that the mineral oil needs to be reapplied more frequently than in the case of Example 1 described above. Specifically, in order to maintain a high glass product disposal rate, it was necessary to reapply mineral oil every time glass products were produced.

  In Example 2, glass products were produced in the same manner as in Example 1 except that the baking step (S50) was omitted.

  In Example 2, even if the production of the glass product was continued for 4 hours, it was not necessary to reapply the release coating agent A. Therefore, according to Example 2, it turned out that the frequency which reapplies a release coating agent can be made lower than the case of the comparative example 1. FIG. However, in Example 2, the frequency of re-applying the release coating agent was higher than in Example 1. This is presumably because the fixing property of the release coating agent to the mold 10 was low. That is, it was found that it is preferable to perform the baking step (S50).

  In the same manner as in Example 1, a mold 10 coated with the release coating agent A was prepared, and production of glass products using the mold 10 was continued for 10 hours. Then, the release coating agent A was applied again to the subsequent mold 10, and a glass product was manufactured using the mold 10.

  In Example 3, even if the production of the glass product was continued for 44 hours, it was not necessary to reapply the release coating agent A. Here, as compared with Example 1, it was found that in Example 3, the time during which the production of the glass product can be continuously performed is longer. The reason for this is that the application of the release coating agent A multiple times not only repairs the deterioration of the release coating agent and unevenness caused by the transfer, but also fixes the release coating agent. This was thought to be due to the increase. Therefore, it has been found that it is effective to reapply the mold release coating agent to the mold 10 already used.

  As in Example 1, a mold 10 was prepared, and glass products were produced using the mold 10. However, the mold release coating agent A was applied to the mold 10 and baked twice.

  In Example 4, even if the production of the glass product was continued for 50 hours, it was not necessary to reapply the release coating agent A. Here, compared with Example 1, in Example 4, it turned out that the time which can produce glass products continuously can be prolonged. The reason for this was thought to be that the application unevenness of the release coating agent was improved and the fixability of the release coating agent was increased by applying the release coating agent A a plurality of times. Therefore, it was found that it is preferable to apply the release coating agent a plurality of times.

  The glass forming method according to the present invention can be used in the field of forming glass using a mold. It can also be used in the field of plastic molding. In addition, the present invention can be applied to a field where a mold is not used at the time of glass molding, when the mold is changed to be used.

DESCRIPTION OF SYMBOLS 10 Mold 10a, 10b Mold piece 11 Hollow part 12 Molten glass ground surface 13 Mold piece ground surface 20 Gob (molten glass)

Claims (4)

A release coating agent containing a silicon compound and alcohol,

When the release coating agent is 100 parts by weight,
The weight of the silicon compound is 10 wt% or more and 40 wt% or less,

When drying the alcohol of the release coating agent by heating,
By the heating, the silicon compound is polymerized to form a film containing a siloxane bond on the surface of the substrate on which the release coating agent is applied.

Heat-resistant release coating agent. The heat-resistant release coating agent according to claim 1, wherein the release coating agent contains acetic acid as a surfactant. The release coating agent further contains zirconia,
The weight ratio of the silicon compound and the zirconia is 2: 1 or more and 6: 1 or less,

By drying the alcohol of the release coating agent by the heating,
The zirconia is dispersed in the coating containing the siloxane bond,

The heat-resistant release coating agent according to claim 1 or 2. The heat-resistant release coating agent according to any one of claims 1 to 3, wherein the alcohol includes isopropanol or ethanol.

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