JPH01228809A - Method for cleaning molding mold - Google Patents

Abstract

PURPOSE:To realize simplification of operation and maintain favorable working atmosphere by a method wherein molding action is performed once by once by placing corresponding sheet between molds respectively to make a mold surface clean and give a mold release agent. CONSTITUTION:A cleaning sheet for a mold employs unvulcanized rubber ground as its basic material, with which a removing aid for peeling-off of a polluting substance of a mold surface smooth from the mold surface and two kinds of groups such as glycol ether group and imidazol group are available as the remove aid. A vulcanizing agent and mold release agent are compounded with the same further and a vulcanization accelerating agent and reinforcement agent are compounded with them at need. A sheet 10 is used, the sheet 10 is made into appropriate dimensions by cutting off the same at an index 11 so that it fits to a molding machine, molding action of which is performed by placing between a top and bottom forces 1, 2 and the surface of the mold is washed. Then a mold release sheet giving the mold release agent to the cleaned mold surface contains the mold release agent in lieu of the glycol ether group or the imidazol group and the molding action is performed by placing the sheet between the molds.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a mold cleaning method for cleaning molds such as molds for thermosetting resin molding materials that have been contaminated due to repeated molding operations. It is about the method.

[Conventional technology].

During molding of the thermosetting resin molding material, the mold release agent contained in the thermosetting resin molding material oozes out onto the mold surface and exhibits a mold release effect. If such molding is repeated, the releasability of the molded product will be significantly deteriorated, phenomena such as roughness will occur on the surface of the molded product, and the surface of the molded product will lose its luster. The reason for this is thought to be that the above-mentioned mold release agent is sequentially laminated on the surface of the mold by repeated molding, and is gradually oxidized and deteriorated to form a hard oxidation-degraded layer of the mold release agent. For example, as shown in FIG. 8, a molten epoxy resin molding material 6 is press-fitted via a runner 5 by the pressing force of a plunger 4 into a cavity 3 formed by an upper mold 1 and a lower mold 2 for transfer molding. After molding, the mold is opened and the molded product 7 is taken out, as shown in FIG. When such molding operations are repeated, an oxidized and deteriorated layer 7a of the mold release agent is formed within the cavity 3. In addition, burrs 8a also remain attached around the cavity such as the mold seam 8. 9 is an air vent section. Once the oxidation-degraded layer 7a of the mold release agent is formed on the cavity surface (mold surface), the mold release agent oozes out from the molding material when the thermosetting resin molding material is molded. However, the release agent acts not on the mold surface but on the oxidation-degraded layer 7a of the mold release agent, making it impossible to exhibit a sufficient mold release effect.

[Problems to be Solved by the Invention] In order to solve such problems, conventionally, at the stage where the release agent oxidation-degraded layer 7a is formed (the stage after the 700 to 100 O shot), a A thermosetting melamine resin molding material is put in and molded to harden, the release agent oxidation-degraded layer 7a on the surface of the mold is integrated with the molded product 7, and the molded product 7 with the oxidation-degraded layer 7a integrated is molded with gold. The surface of the mold is cleaned by removing it from the mold. In this case, formalin is produced as a condensate of the thermosetting melamine resin molding material and causes odor etc.
This deteriorates the working environment and causes a decline in cleaning work efficiency.

When the mold surface is cleaned using the thermosetting melamine resin molding material in this manner, the mold surface is completely cleaned, so that no mold release agent is present on the mold surface. Therefore, if the molding material is molded in the absence of a mold release agent on the mold surface, the molded product will adhere to the mold surface and will not be released smoothly. This is because the mold surface is completely cleaned, so the mold release agent oozes from the molding material and does not adhere sufficiently to the mold surface during the -th molding. Therefore, conventionally, the internal mold release agent contained in the mold material was preformed two to three times (this is called a dummy shot) using a molding material so that the mold release agent sufficiently adhered to the mold surface. After sufficient adhesion to the mold surface, normal molding is carried out. However, performing two to three dummy shots in this manner is extremely uneconomical, and this is a cause of a decrease in molding efficiency.

This invention was made in view of the above circumstances, and it is possible to easily clean the mold surface and apply a mold release agent to the mold surface without deteriorating the working environment or performing dummy shots. Its purpose is to make it possible.

[Means for solving problems]

In order to achieve the above object, the mold cleaning method of the present invention includes the steps of sandwiching a mold cleaning sheet made of unvulcanized rubber fabric as a base material between a pair of molds, and A process of operating the molding molds to clean the mold surfaces, a process of removing a mold cleaning sheet from between the pair of molds after the molding operation, and a process of cleaning the mold surfaces of the pair of molds with the mold surfaces cleaned. A process of sandwiching a release sheet made of unvulcanized rubber material as a base material and containing a release agent between the molds, and in this state, a pair of molding molds are operated to form the mold, and the mold is released on the mold surface. and a step of applying an agent.

[Function] As a result of a series of studies on the cleaning effect on the above-mentioned molding molds, the present inventors have found that, in particular, using a sheet made of unvulcanized rubber fabric as a base material, the sheet is placed between the molding molds. When the mold is pressed and the mold is operated, the unvulcanized rubber material is vulcanized and contaminants on the surface of the mold are transferred into the vulcanized rubber, causing the vulcanized rubber to become vulcanized. It has been found that the surface of the mold can be easily cleaned when removed from the mold. In this case, when the unvulcanized rubber is vulcanized in the mold, there is no odor such as formalin odor or amino acid odor, and there is no problem of deterioration of the working environment. In addition, as a result of repeated research, we were able to start the molding process immediately after cleaning the mold with a cleaned mold surface without having to perform a dummy shot. When a mold release sheet made of rubber fabric as a base material and containing a mold release agent is sandwiched between a mold with a cleaned mold surface and the molding operation is performed in the same manner as above, the mold surface is cleaned and becomes mirror-like. The mold release agent exudes from the unvulcanized rubber material and adheres to the mold surface, forming a uniform release agent film on the mold surface. This invention was achieved by discovering that the molding process can be started immediately. That is, by simply inserting the above-mentioned mold release sheet between the cleaned molds, heat-molding it twice, and then peeling off the sheet, the surface of the mold that has been cleaned and has a mirror-like finish is removed. On the other hand, a release agent film is formed uniformly. Therefore, the molding operation can be started immediately without performing a dummy shot, which improves the efficiency of the molding operation. Moreover, since the mold release agent applying operation only needs to be performed twice, it is possible to significantly improve the work efficiency of the mold release agent applying operation.

The mold cleaning method of this invention uses two types of sheets: ■ a mold cleaning sheet and ■ a mold release sheet, and cleans the mold using only the surface of the mold. Na(,
The area around the mold (around the cavity) can also become contaminated due to repeated molding. In such cases, a cleaning sheet around the molding area is used to clean only the area around the mold cavity. Since the mold dimensions of these three types of sheets vary depending on the molding machine manufacturer, the sheet itself is set to the maximum size among them, and the individual molds are In other words, in each of these three types of sheets, marks 11 for cutting the sheet 10 into an appropriate size are placed at predetermined intervals, as shown in FIG. In FIG. 1, the mark 11 is formed by a notch, the depth of which is set to about 2/3 of the thickness of the sheet 10. Then, the sheet 10 can be cut to an appropriate size using the notches. FIG. 2 shows how this cut is formed. In addition, as mentioned above, 2
Instead of making the incision to the extent of /3, the incision may be made to about half the thickness, as shown in FIG.

Formation of such cuts may be performed using a ribbon slitter having disc-shaped cutting blades 13 at predetermined intervals on the rotating shaft 12, as shown in FIG. 4, for example, or by using a ribbon slitter as shown in FIG. Alternatively, an embossing cutter having abacus spherical cutting blades 14 at appropriate intervals on the rotating shaft 12 may be used. Also, instead of making a notch as shown above,
You can also mark it by printing. In this case, cutting is performed along the marks using a knife or the like. Alternatively, it is also possible to print and then make incisions on the print. Furthermore, the condition of the marks is not limited to the shape of the base hole shown in Figure 1, but parallel lines may be placed in only one direction, or marks may be placed at regular intervals only on the periphery of the sheet. You may also do so. Note that when the above-mentioned marks are formed at regular intervals, the marks also function as a measuring tape.

Next, of the three types of sheets mentioned above, first, a mold cleaning sheet for cleaning the mold surface of a molding die will be explained.

This mold cleaning sheet has an unvulcanized rubber fabric as its base material, and may be composed only of the unvulcanized rubber fabric, but it usually contains contaminants on the mold surface (oxidation of the mold release agent). A removal aid is added to smoothly peel off the degraded layer from the mold surface. There are two types of mold cleaning sheets made of this type of removal aid and unvulcanized rubber material. The first one is
The base material is an unvulcanized rubber fabric made of a mixture of glycol ethers represented by the general formula (1) and unvulcanized rubber.

R,0-(C)lzcHzO)--Rz・・・・・・(
1) Examples of glycol ethers represented by the above general formula (1) include ethylene glycol dimethyl ether and diethylene glycol dimethyl ether.

Triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol diethyl ether, diethylene glycol propyl ether, diethylene glycol dibutyl ether, ethylene glycol Examples include monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether.

Among the glycol ethers represented by the above general formula (1), when n = 1 to 2 and one of R, , R, is hydrogen, the other is an alkyl group having 1 to 4 carbon atoms, and ,R
,,R, are both alkyl groups, the number of carbon atoms is 1 to
4 is preferably an alkyl group. In addition, the above n
When it takes a value of 3 or more, the compatibility with the rubber decreases, and when the number of carbon atoms in the alkyl group is 5 or more, the permeability of the release agent to the oxidation-degraded layer becomes poor. A trend can be seen.

The above-mentioned glycol ethers can be used as such, or in the form of water, alcohols such as methanol, ethanol, n-propanol, or toluene.

It may be used in combination with an organic solvent such as xylene.

When mixing with organic solvents, the amount of organic solvent is usually
For 1,100 parts by weight of glycol ether (hereinafter abbreviated as "parts"), the amount is usually 50 parts or less, most commonly 20 parts or less. Further, there is no problem in using a conventionally used mold release agent in an appropriate amount as necessary. When using a mold release agent in combination, the amount used should be 10
0 parts to 10 parts or less, most commonly 2 to 5 parts.

Unvulcanized rubber includes natural rubber (NR), chloroprene rubber (CR), butadiene rubber (BR), nitrile rubber (NBR), ethylene propylene terpolymer rubber (EPT), ethylene propylene rubber (EPM),
The main components are styrene-butadiene rubber (SBR), polyisoprene rubber (IR), butyl rubber (IIR), silicone rubber (Q), fluororubber (FKM), etc. alone or in combination, and a vulcanizing agent is further blended. Depending on the situation, vulcanization accelerators, reinforcing agents, etc. are used. This unvulcanized rubber is vulcanized in the mold to become vulcanized rubber. The above unvulcanized rubber is preferably E
PT, SBR, NBR or a mixture thereof.

The EPT is a cyclic or acyclic copolymer having ethylene, an α-olefin, and a nonconjugated double bond. To elaborate on this, EPT is ethylene, α
- A terpolymer consisting of an olefin (especially propylene) and the polyene monomers listed below, where the polyene monomers include dicyclopentadiene, 1,
5-cyclooctadiene, 1.1-cyclooctadiene, 1.6-cyclodozocadiene, 1.7-cyclodozocadiene, 1,5.9-cyclododecatriene, 1.4-
Cyclohebutadiene, 1,4-cyclohexadiene, norbornadiene, methylenenorbornene, 2-methylpentadiene-1,4,1,5-hexadiene, 1.6-
Hebutadiene, methyl-tetrahydroindene, 1,4
-Hexadiene, etc. The copolymerization ratio of each 1,000 units is
Preferably 30 to 80 mol% of ethylene and 0% of polyene
．． It is a terpolymer in which the remaining amount is α-olefin at 1 to 20 mol%.

More preferred is one containing 30 to 60 mol% of ethylene. and the Mooney viscosity M L . 4 (100°
C) is preferably 20 to 70. As a specific example of the above EPT, Mitsui EPT4021. manufactured by Mitsui Petrochemical Industries, Ltd.
4045. I can give you 4070. Also,
SBR has a styrene content of 15 to 30 mol% and a Mooney viscosity M L .

(100°C) is preferably 20 to 80, preferably 35 to 60. As a specific example, manufactured by Japan Synthetic Rubber Co., Ltd., J
SR-1502, SR-1507. 1778 can be mentioned. NBR has an acrylonitrile content of 2
It is suitable to use 0 to 60 mol%, preferably 25 to 45 mol%, and a Mooney viscosity ML+, 4 (100°C) of 20 to 85, preferably 30 to 70.

Specific examples include N-234L and 23 manufactured by Japan Synthetic Rubber Co., Ltd.
O.S.

You can raise 230SH.

The above-mentioned glycol ethers become unvulcanized rubber dough by mixing with the above-mentioned unvulcanized rubber.

In this case, glycol ethers are unvulcanized rubber 100%
It is usually blended in 10 to 60 parts. The preferred amount is about 15 to 25 parts. The boiling point of the glycol ethers is preferably about 130 to 250°C. That is, mold forming is usually performed at 150 to 185 degrees.
If the boiling point of the glycol ether is less than 130°C, evaporation during washing will be significant.
Therefore, there is a risk of deterioration of the cleaning work environment.On the other hand, if the temperature exceeds 250°C, it will be difficult to evaporate and remain in the vulcanized rubber, causing problems when the vulcanized rubber is removed from the mold. Since the strength is weakened and the shape collapses, it becomes difficult to sufficiently peel off the oxidized and degraded layer of the mold release agent from the mold surface, reducing cleaning workability (because the amount of spray is observed).

In addition, the sheet for mold recycling using the unvulcanized rubber fabric as a base material contains inorganic reinforcing agents such as silica, alumina, calcium carbonate, aluminum hydroxide, titanium oxide, etc., in addition to the unvulcanized rubber. It is also possible to incorporate fillers). In this case, the amount of reinforcing agent used is 100% of unvulcanized rubber.
It is preferable to set the amount to 10 to 50 parts.

Furthermore, as mentioned above, it is also possible to incorporate a mold release agent. Examples of the above mold release agent include stearic acid, zinc stearate, carnauba wax, monk wax, and stearyl ethylene diamide. It is possible to mix 1 to 10 parts of these to 100 parts of unvulcanized rubber.

The other of the two types of mold cleaning sheets mentioned in (1) above uses one or both of imidazoles and imidazolines in place of the glycol ethers. Other than that, it is exactly the same as the mold recycling sheet described above.

As the above-mentioned imidazoles, good results can be obtained by using imidazoles represented by the following general formula (. Representative examples of such imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, ,
2-phenylimidazole, 1-benzyl-2-methylimidazole, etc., 2,4-diamino-6[2°-methylimidazolyl(1)')ethyl-5-)riazine, 2
Examples include ゜4-diamino-6[2゛-ethyl-4'-methylimidazolyl-(1)')ethyl-s-triazine.

In addition, as the above imidazolines, the following general formula (3
) The use of imidazolines represented by the following gives good results. Representative examples of such imidazolines include 2
-Methylimidazoline, 2-methyl-4-ethylimidazoline, 2-phenylimidazoline, 1-benzyl-2
-Methylimidazoline, 2-phenyl-4-methyl-5
-Hydroxymethylimidapurine, 2,4-diamino-
6[2'methylimidazolylyl(1)"]ethyl-8-triazine2,4-diamino-6[2"-methyl-
4゛-ethylimidasilylyru(1)”]ethyl=S-
) riazine, (1)-cyanoethyl-2-methylimidazoline, 1-cyanoethyl-2-methyl-4-ethylimidazoline, and the like.

Next, a specific example of the above-mentioned two types of mold surface cleaning mold regeneration sheets in which glycol ethers are contained in the unvulcanized rubber dough will be explained.

(Specific Example A) The rubber shown in Table 1 below and the raw materials shown in the same table are kneaded using a kneading roll, and then formed into a sheet with a thickness of 7 mm using a rolling roll. Cuts in the 5th cylinder were formed parallel to the width direction of the sheet.

(Left below) Using the mold recycling sheet obtained as described above, cut it from the above notch to the appropriate size to fit several types of transfer molding machines with different mold dimensions, and then cut it into the appropriate size as shown in Figure 6. This was used to clean the mold surfaces of the upper mold 1 and the lower mold 2. 10 is a sheet for mold regeneration in a compressed state, and 4 is a plunger. The results are shown in Table 1 above,
The actual height measurements were extremely good compared to the comparative height measurements.

[Specific example B]

Next, a specific example of the above-mentioned two types of mold surface cleaning mold recycling sheets in which imidazoles are contained in the unvulcanized rubber dough will be shown. That is, the raw materials shown in Table 2 below are mixed in the proportions shown in the same table, kneaded with a kneading roll, formed into a sheet with a thickness of 7 bars using a rolling roll, and marked with 10 square base marks by printing. did.

(Left below) Using the mold recycling sheet obtained as described above, cut it with a knife to the appropriate size according to the printed marks on the base board to fit several types of transfer molding machines with different mold dimensions. It was used to clean the mold surface. The results are shown in Table 2 above, and the concrete height measurements were extremely good compared to the comparative height measurements.

Next, the mold recycling sheet used for cleaning the area around the mold forming part (2) will be explained.

This type of mold recycling sheet is used more frequently than the mold cleaning sheet described above, and it uses an unvulcanized rubber base material on one or both of the front and back surfaces of a sheet-like fiber base material. It is formed in a layered form, and is finished to be extremely thin, with a thickness of about 0.2 to 1.0 mm, compared to those intended for cleaning the mold surface (cavity surface).

The sheet-like fiber base materials used for this mold recycling sheet include nonwoven fabrics of various materials, such as organic fiber nonwoven fabrics such as polyester nonwoven fabrics, glass vapor, inorganic fiber nonwoven fabrics such as glass fiber nonwoven fabrics, cellulose-mixed glass paper, and paper. Examples include materials. In some cases, a woven fabric or the like may be used instead of the above-mentioned nonwoven fabric. As an example of the above-mentioned nonwoven fabric, the nonwoven fabric made of polyester fibers includes IEL E1030 manufactured by Asahi Kasei Corporation. Ei050,E
Iloo is mentioned, and D-3038 and D-30 manufactured by Igechu Corporation are used as soft cheesecloth made of rayon fiber.
42 can be given. In addition, as a glass cheesecloth made of glass fiber, WK-3025A-104 manufactured by Unitika Co., Ltd.
, WL-110B-28, KC-0808B-104-
ABI can be given.

The unvulcanized rubber fabric base material formed in layers on one or both of the front and back surfaces of the sheet-like fiber base material is removed at the seam between the upper mold 1 and the lower mold 2 during the cleaning operation shown in FIG. It is heated and vulcanized to become vulcanized rubber around the mold, and at that time, contaminants such as slag that have adhered around the molding parts such as the mold joining part are integrated, and the recycling sheet 10 is put into the mold. When peeling and removing from the mold, contaminants such as sludge from around the molded part are peeled and removed. As such unvulcanized rubber, the same rubber as that used in the mold recycling sheet for cleaning the mold surface is used, and EPT, like the mold recycling sheet, is particularly preferred. Also, blending silica or the like as a reinforcing agent with such unvulcanized rubber is similar to the mold recycling sheet.

This mold forming area cleaning sheet is made by blending unvulcanized rubber with reinforcing agents as needed, kneading it with a kneading roll to form a thin sheet, and then layering this with a sheet-like fiber base material and rolling it into a calendar roll. It can be manufactured by applying pressure to form a body.

Next, a specific example of a mold recycling sheet used for cleaning the area around the mold forming part will be explained.

[Specific example C]

After blending the raw materials shown in Table 3 below and kneading them with a kneading roll, unvulcanized rubber and nonwoven fabric, etc. are formed into a sheet with a thickness of 0.511 inch using a calendar roll, and a 10 mm square base plate is printed. A landmark was formed.

(Margin) The sheet for mold recycling obtained as described above was cut with a knife from the printed mark to the appropriate size so that it could be adapted to transfer molding machines with several types of mold sizes. Then, the area around the molding part was cleaned using this. The results are shown in Table 3 above, and it can be seen that concrete height measurement has excellent performance.

Next, on the mold surface that has been cleaned using the mold cleaning sheet (■) (there is no mold release agent at all and if molded as is, the molded product will adhere to the mold surface and will not be released). The release sheet (2) whose purpose is to apply a release agent will be explained below.

That is, this mold release sheet contains a mold release agent in place of the glycol ethers and imidazoles of the mold regeneration sheet for the purpose of cleaning the mold surface.

Mold release agents of this type include long chain fatty acids such as stearic acid, behenic acid, and zinc stearate.

Long-chain fatty acids (D
Gold E'X salt, carnauba wax, montan wax.

Examples include ester waxes represented by partially saponified esters of montanic acid, long-chain fatty acid amides represented by stearyl ethylene diamide, and paraffins represented by polyethylene wax.

This release sheet can be obtained by mixing the above-mentioned release agent and the above-mentioned unvulcanized rubber using a known method, for example, using a calendar roll, or by preparing an unvulcanized rubber dough in advance, It can also be obtained by a method such as kneading a mold release agent into this. In these cases, the release agent is usually mixed in an amount of 1 to 50 parts per 100 parts of the unvulcanized rubber dough.

The preferred amount is 3 to 20 parts. The above-mentioned mold release agent has a melting point of 200°C or less and a boiling point of 20°C or less.
Preferably, the temperature is 0°C or higher. Furthermore, those having a melting point of 50 to 150°C are preferable. That is, mold molding is usually performed at 150 to 200°C, and if the melting point of the mold release agent is higher than 200°C, it will not ooze out onto the mold surface, and if the mold release agent has a boiling point of less than 200°C. If so, even if it oozes into the mold, it will evaporate and tend to no longer function.

In addition, for the unvulcanized rubber fabric in the above-mentioned mold release sheet, similar to the above-mentioned mold surface cleaning mold recycling sheet,
Other additives such as silica can be incorporated as well.

Next, a specific example of this release sheet will be explained.

[Specific example D]

Blend the raw materials shown in Table 4 below, form this into a sheet with a thickness of 7 using a rolling roll, and make stripes of 10 mm in width and 5 in depth parallel to the width direction of the sheet. A release sheet was obtained.

(Hereinafter, the rest is white) The mold release sheet obtained as above is folded from the above mark to the appropriate size to fit the molds of several types of transfer molding machines with different mold dimensions, and this is used to mold the mold. Place it between the thermosetting resin molds whose surfaces have been cleaned, and 17
Vulcanize at 5°C for 4 minutes, open the mold immediately after curing,
The molded vulcanized rubber was taken out. Thereafter, a thermosetting resin molding material epoxy resin molding material (manufactured by Nitto Denko Corporation, MP-10) was molded by a normal molding method using the mold to which a mold release agent was applied as described above. The release status of the product was examined. The results are shown in Table 4 above in comparison with a comparative example (one dummy shot).

As is clear from Table 4, according to the specific examples, extremely good mold releasability can be imparted.

Next, an example in which molding is performed continuously using the above-mentioned sheet will be described.

[Example 1] Using the mold cleaning composition prepared in the specific example B-3, 1000 shots of MP-10 manufactured by Nitto Denko were molded, the dirty mold was cleaned, and then the mold cleaning composition prepared in the specific example B-3 was molded. Apply a mold release agent to the mold using the mold release sheet prepared in D-3,
Molding was performed using Niki MP-10. Then, deburring was performed every 50 shots using the cleaning sheet around the molding area prepared in Example C-4. In this way, resin molded articles were produced continuously.

[Example 2] 1000 shots of MP-10 manufactured by Nitto Denko were molded,
The mold in which dirt was formed was cleaned using the mold cleaning sheet obtained in Specific Example B-2. After cleaning, a mold release agent is applied to the cleaned mold using the mold release sheet obtained in Example D-2, and then the MP
-10 was used for molding. Molding was performed continuously in this manner.

[Comparative example]

1000 shots of MP-10 manufactured by Nitto Denko were molded.
The dirty mold was cleaned using a melamine resin molding material. Then, MP- used in Comparative Example D-1
Three dummy shots of No. 10 were performed to apply a mold release agent to the cleaned mold surface. After the dummy shot, continuous molding was performed using the above Ml''-10.

The results obtained in the above Examples and Comparative Examples will be summarized in the fifth section below.
Shown in the table.

(Margins below) 1st person *1: Good indicates that the mold is in its initial mirror-like state, and poor indicates that the dirt has not been removed and a cloudy phenomenon has occurred.

*2: Good indicates that the area around the molded part is in the initial mirror-like state.

From the results in Table 5, it can be seen that the height measurements carried out had good mold cleanability and mold releasability, and that excellent results were obtained.

〔Effect of the invention〕

As described above, in the mold cleaning method of the present invention, when the mold surface is contaminated due to continuous molding operations, a mold cleaning sheet made of unvulcanized rubber material is placed between the molds. By sandwiching the material between the two and performing the molding operation, the contaminants are adsorbed onto the unvulcanized rubber fabric, and the adsorbed unvulcanized rubber fabric is converted into a fluidized rubber by heating during the above-mentioned molding process, making it into a strong state. The mold release sheet is made to be easily peelable from the mold surface, and then the mold release sheet is stacked on the cleaned mold surface and the molding operation is performed, thereby applying the mold release agent to the mold surface and simultaneously applying the mold release agent. By heating during molding, the unvulcanized rubber fabric of the release sheet is turned into vulcanized rubber, making it strong and easy to peel off. Therefore, it is now possible to clean the mold surface and apply mold release agent by simply running the molding operation once by sandwiching the respective sheets, making it possible to clean the mold surface and apply mold release agent. Significant simplification can be achieved. Moreover, at that time, a good working environment can be maintained without generating formalin odor or amine odor, unlike when cleaning molds using conventional melamine resin molding materials.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a mold cleaning sheet used in this invention;
FIG. 2 is an explanatory diagram of the notch portion, FIG. 3 is an explanatory diagram of a modified example of the notch portion, FIGS. 4 and 5 are explanatory diagrams of the formation of the notch, and FIG. 6 is an explanatory diagram of an embodiment of the present invention. FIG. 7 is an explanatory diagram of the operation of another embodiment, and FIGS. 8 and 9 are explanatory diagrams of the conventional example. 10... Sheet 11... Landmark Patent applicant Kyushu Nitto Denko Co., Ltd. Agent Patent attorney Yukihiko Nishifuji Figure 1 g2 Figure 4 Figure 5

Claims (4)

[Claims] (1) A process in which a mold cleaning sheet made of unvulcanized rubber material is sandwiched between a pair of molds, and in this state, the pair of molds are operated to clean the mold surface. The process of removing the mold cleaning sheet from between the pair of molding molds after the molding operation, and the step of separating the unvulcanized rubber fabric as a base material between the pair of molding molds whose mold surfaces have been cleaned. Molding characterized by comprising a step of sandwiching a mold release sheet containing a mold agent, and a step of operating a pair of molding molds in that state to apply a mold release agent to the mold surface. Mold cleaning method. (2) The mold cleaning method according to claim (1), wherein the unvulcanized rubber dough comprises unvulcanized rubber and a removal aid. (3) Claim (1) or (2) wherein the removal aid is at least one compound selected from the group consisting of glycol ethers, imidazoles, and imidazolines.
The mold cleaning method described. (4) The mold cleaning sheet has marks on the sheet surface at predetermined intervals for cutting the sheet into appropriate dimensions, and the mold cleaning sheet is cut into appropriate dimensions using the marks ( 1) The mold cleaning method according to any one of (3).