JP2703738C - - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning and regenerating a mold such as a molding die for a thermosetting resin molding material contaminated by repetition of a molding operation. The present invention relates to a mold regeneration sheet to be used. 2. Description of the Related Art During molding of a thermosetting resin molding material, a release agent contained in the thermosetting resin molding material exudes to the surface of a mold to exhibit a releasing effect. When such molding is repeated, the releasability of the molded article is remarkably deteriorated, and the surface of the molded article suffers from a phenomenon such as a rough surface, and the molded article surface does not have gloss or the like. It is considered that the reason for this is that the release agent is successively laminated on the mold surface by repeating molding, and is gradually oxidized and deteriorated to form an oxidized layer of a hard release agent. For example, as shown in FIG. 7, a plunger 4 is provided in a cavity 3 formed by an upper mold 1 and a lower mold 2 of transfer molding.
After the molten epoxy resin molding material 6 is press-fitted through the runner 5 with the pressing force and molded, the mold is opened and the molded product 7 is taken out as shown in FIG. By repeating such a molding operation, an oxidation-degraded layer 7a of the release agent is formed in the cavity 3. Further, the burrs 8a also adhere and remain around the cavities such as the mold joint 8 and the like. 9 is an air vent part. Once such an oxidation-degraded layer 7a of the release agent is formed on the cavity surface (mold surface), when the thermosetting resin molding material is subsequently molded, the release agent oozing out of the molding material However, this acts not on the mold surface but on the oxidation-degraded layer 7a of the release agent, so that a sufficient release effect cannot be exhibited. In order to solve such a problem, conventionally, at the stage (700 to 1000) at which the release agent oxidation-deteriorated layer 7a is formed.
In a step after the shot), a thermosetting melamine resin molding material is put into the mold and molded and cured, and the release agent oxidation-deteriorated layer 7a on the mold surface is integrated with the molded article 7, and the oxidation The mold surface is cleaned by removing the molded article 7 with the deteriorated layer 7a integrated from the mold. In this case, since formalin is by-produced as a condensate of the thermosetting melamine resin molding material to generate odor and the like, the working environment is deteriorated and the cleaning workability is reduced. SUMMARY OF THE INVENTION The inventors of the present invention have used an unvulcanized rubber base material as a base material and a glycol base material for the purpose of removing the oxidatively degraded layer of the mold release agent on the mold surface as described above. Developed a sheet-shaped mold detergent composition containing ethers (hereinafter abbreviated as “sheet-shaped composition”) and already applied for a patent (
(Japanese Patent Application No. 61-252536). Mold cleaning with the sheet composition is performed as follows. That is, the sheet-shaped composition is sandwiched between upper and lower molds, and the sheet-shaped composition is pressed against the surface of the mold by pressure during molding, and in this state, the sheet-shaped composition is heated using heat during molding. The whole of the above sheet-shaped composition is vulcanized by heating and vulcanized, and the release agent oxidation-degraded layer on the mold surface is integrated with the vulcanized rubber during the vulcanization, and the mold is opened. After that, the vulcanized rubberized high-strength, high-elastic sheet-like composition is released from the mold, whereby the oxidation-degraded layer integrated with the sheet-like composition is released from the mold surface. This is done by: The use of such a sheet-like composition does not cause a problem as in the case of using the thermosetting melamine resin molding material as described above. Then, the mold surface is also cleaned to the initial mirror surface state, similarly to the cleaning using the melamine resin molding material. However, in general,
The dimensions of the mold in a transfer molding machine and the like vary depending on the manufacturer. Therefore, the sheet-shaped composition is also set to the size of the largest one of them, and the size of the sheet-shaped composition is determined according to each mold in use. Cutting is performed in aliquots. However, it is inaccurate to perform the cutting with the granularity in such a manner, and in some cases, it is inconvenient that the cutting is smaller than the mold size and cannot be used. In addition, there is a problem that fatigue is great because the nerve is used for cutting. [0004] In use, the sheet-shaped composition is cut into two or three layers according to individual molds at the time of use. However, when stacking the products cut by the unit as described above, the sizes are not uniform, or the stacked sheets are shifted, and the shape of the stacked products tends to be distorted, and this is sandwiched in a mold. In such a case, the composition does not spread evenly in the cavity, and the unvulcanized rubber is partially not sufficiently pressed against the mold surface, resulting in poor cleaning. To avoid this, it is necessary to measure the dimensions in advance, cut the sheet to the same size using a knife, etc., and align the left, right, front, and back edges of the cut, and stack them. Has contributed to [0005] The present invention has been made in view of such circumstances, and accurately performs cutting.
It is another object of the present invention to provide a mold regeneration sheet that can be easily performed. [0006] In order to achieve the above object, a sheet for mold regeneration according to the present invention comprises an unvulcanized rubber material containing no imidazole or imidazolines. With the base material as the base material,
A plurality of linear marks for cutting the sheet into appropriate dimensions are provided in parallel, and these marks are formed by cuts that can be cut from the mark portions. [0007] That is, as described above, as a result of the provision of the mark on the sheet, the sheet can be cut with the mark as a guide, and therefore, compared with the case where the sheet is cut by the conventional amount. The cutting can be performed accurately, and the cutting is also facilitated. For this reason, the sheet can be cut into a desired size from the above-mentioned cut by hand without using a cutting tool in accordance with the size of the molding die, and the washing operation can be simplified. . According to the present invention, a sheet having a predetermined dimension is cut in parallel with mass production, and the user of the molding die purchases it, and cuts or bends appropriately according to the dimension of the molding die. It can be used as it is, making it easier to use.
Further, cutting and bending operations can be easily performed. Further, according to the present invention, since the unvulcanized rubber is used as a base material and the mark is formed by a cut that can be cut, even if the cut portion is bent, the cut portion is immediately connected to the cut bottom. It cannot be torn. For this reason, the sheet can be easily folded to form a multilayer. As a result, there is an effect that the cleaning failure can be prevented and the work can be rationalized. That is, in the present invention, since the individual strip-shaped sheets separated by parallel cuts are connected to each other at the bottom of the cuts, they are stacked neatly without shifting when folded, and each strip-shaped sheet is Will not be piled up when crossed. By cleaning with the sheets stacked neatly, the unvulcanized rubber spreads evenly in the cavity, and cleaning failure does not occur. In addition, a complicated operation of measuring the dimensions of the sheet and cutting it into the same size or stacking the cut pieces while aligning the ends thereof is not required, and the cleaning operation is rationalized. Next, the present invention will be described in detail. [0010] The sheet for mold regeneration of the present invention is based on an unvulcanized rubber base material, and is intended for cleaning the mold surface (cavity surface) as described above. The purpose of which is to apply a release agent to the mold surface after cleaning in order to facilitate the release of the molded product formed for the first time after the cleaning of the mold surface (cavity surface). There is something. In each of these two types of mold regeneration sheets, for example, as shown in FIG. 1, a plurality of linear marks 11 for cutting the sheet 10 into appropriate dimensions are arranged at regular intervals on most of the sheet surface. They are provided in parallel. Mark 11 above
Is formed by cutting, and the depth thereof is set to about ／ of the thickness of the sheet 10. The sheet 10 can be cut to an appropriate size by using the cut. FIG. 2 shows a state in which the cuts are formed. Instead of making a cut to about 2/3 as described above, a cut may be made to about half of the thickness as shown in FIG. For example, as shown in FIG. 4, such a cut may be formed by using a ribbon slitter having a disk-shaped cutting blade 13 at predetermined intervals on a rotating shaft 12, or as shown in FIG. As described above, the rotation may be performed using an emboss cutter having an abacus bead cutting blade 14 at an appropriate interval on the rotating shaft 12. Further, the state of the mark is not limited to a grid pattern as shown in FIG. 1, and a parallel line may be formed in only one direction. In addition, when the marks are formed at regular intervals, the marks also serve as a measure. Next, a mold regeneration sheet used for cleaning the mold surface (cavity surface) will be described. [0013] The unvulcanized rubber material consisting of a mixture of unvulcanized rubber and glycol ethers represented by this compound the general formula (1) in which a base material. Embedded image The glycol ethers represented by the general formula (1) include ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol. Monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol diethyl ether, diethylene glycol propyl ether, diethylene glycol dibutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol Recall monobutyl ether and the like. Among the glycol ethers represented by the general formula (1), n = 1 to 2, R
_When either _one of R ₁ and R ₂ is hydrogen, the other is an alkyl group having 1 to 4 carbon atoms. When both R ₁ and R ₂ are an alkyl group, the other is an alkyl group having 1 to 4 carbon atoms. It is preferably a group. When the value of n is 3 or more, the compatibility with rubber is reduced, and when the alkyl group has 5 or more carbon atoms,
There is a tendency that the permeability of the release agent to the oxidatively deteriorated layer is deteriorated. The above glycol ethers may be used as they are, or mixed with water or alcohols such as methanol, ethanol and n-propanol, and organic solvents such as toluene and xylene. When mixing with an organic solvent, the amount of the organic solvent is usually adjusted to 50 parts or less based on 100 parts by weight of glycol ethers (hereinafter abbreviated as "part"), and most commonly to 20 parts or less. Is done. In addition, an appropriate amount of a conventionally used release agent may be used in combination as needed. When a release agent is used in combination, the amount of the release agent is adjusted to 10 parts or less based on 100 parts of the total amount of the unvulcanized rubber base and the glycol ethers, and most commonly 2 to 5 parts. Is done. Examples of the unvulcanized rubber include natural rubber (NR), chloroprene rubber (CR), butadiene rubber (BR), nitrile rubber (NBR), ethylene propylene terpolymer rubber (EPT), ethylene propylene rubber (EPM), It contains singly or a mixture of styrene butadiene rubber (SBR), polyisoprene rubber (IR), butyl rubber (IIR), silicone rubber (Q), fluorine rubber (FKM), etc., and further contains a vulcanizing agent. Those containing a vulcanization accelerator, a reinforcing agent and the like are used accordingly. This unvulcanized rubber is vulcanized in a mold to become a vulcanized rubber.
Preferred as the unvulcanized rubber is EPT, SBR, NBR or a mixture thereof. The EPT is a copolymer comprising ethylene, an α-olefin and a cyclic or non-cyclic having a non-conjugated double bond. To elaborate on this,
EPT is a terpolymer composed of ethylene, α-olefin (particularly, propylene) and the polyene monomers listed below.
Dicyclopentadiene, 1,5-cyclooctadiene, 1,1-cyclooctadiene, 1,6-cyclododecadiene, 1,7-cyclododecadiene, 1,5,9
-Cyclododecatriene, 1,4-cycloheptadiene, 1,4-cyclohexadiene, norbornadiene, methylenenorbornene, 2-methylpentadiene-
1,4,1,5-hexadiene, 1,6-heptadiene, methyl-tetrahydroindene, 1,4-hexadiene and the like. The copolymerization ratio of each monomer is preferably 30 to 80 mol% of ethylene, 0.1 to 20 mol% of polyene, and α-
It is a terpolymer that becomes an olefin. More preferably, the ethylene content is 30 to 60 mol%. And Mooney viscosity ML _{1 + 4} (100 ° C) is 20
~ 70 is preferred. Specific examples of the EPT include Mitsui Petrochemical Industries, Ltd., Mitsui EPT4021, 4045, and 4070. Also, SB
As R, the styrene content is 15 to 30 mol% and the Mooney viscosity ML _{1 + 4} (100
C) of 20 to 80, preferably 35 to 60. Specific examples include JSR-1502, 1507 and 1778 manufactured by Japan Synthetic Rubber Co., Ltd. As the NBR, those having an acrylonitrile content of 20 to 60 mol%, preferably 25 to 45 mol%, and a Mooney viscosity ML _{1 + 4} (100 ° C.) of 20 to 85, preferably 30 to 70 are suitable. . Specific examples include N-234L, 230S, and 230SH manufactured by Nippon Synthetic Rubber Co., Ltd. The glycol ethers are mixed with the unvulcanized rubber to form an unvulcanized rubber material. In this case, the glycol ethers are usually blended in an amount of 10 to 60 parts based on 100 parts of the unvulcanized rubber. Preferred is about 15 to 25 parts. The boiling point of the glycol ethers is preferably about 130 to 250 ° C. That is, mold molding is usually performed at 150 to 185 ° C. If the glycol ethers have a boiling point of less than 130 ° C, evaporation during washing is remarkable,
Therefore, there is a possibility that a deterioration phenomenon of the cleaning work environment may occur. Conversely, when the temperature exceeds 250 ° C., evaporation is difficult and remains in the vulcanized rubber, and the vulcanized rubber may be removed from the mold. This is because the strength is weakened and the shape of the mold deteriorates, so that the oxidation-degraded layer of the release agent cannot be sufficiently peeled off from the mold surface, which tends to lower the cleaning workability. In addition, in the sheet for mold regeneration using the unvulcanized rubber material as a base material, silica, alumina, calcium carbonate, aluminum hydroxide,
It is also possible to incorporate an inorganic reinforcing agent (filler) such as titanium oxide. In this case, the amount of the reinforcing agent used is preferably set to 10 to 50 parts based on 100 parts of the unvulcanized rubber. Further, as described above, a release agent can be blended.
Examples of the release agent include stearic acid, zinc stearate, carnauba wax, montan wax, and stearyl ethylenediamide. It is possible to mix 1 to 10 parts of these with 100 parts of unvulcanized rubber. [0021] Next, a specific example will be described but was contained glycol ethers in the unvulcanized rubber material. [Specific Example A] The rubber shown in Tables 1 and 2 below and the raw materials shown in the table are kneaded with a kneading roll, and then formed into a sheet having a thickness of 7 mm using a rolling roll. 10
A cut having a width of 5 mm and a depth of 5 mm was formed in parallel with the width direction of the sheet. [Table 1] [Table 2] Using the sheet for mold regeneration obtained as described above, the sheet is divided from the above-mentioned cut portion to an appropriate size so as to be suitable for several types of transfer molding machines having different mold dimensions,
As shown in FIG. 6, the upper mold 1 and the lower mold 2 were used for cleaning the mold surfaces. Reference numeral 10 denotes a compressed mold regeneration sheet, and reference numeral 4 denotes a plunger. The results are as shown in Tables 1 and 2 above, and the product of the example was much better than the product of the comparative example. Next, the mold surface cleaned using a mold regenerating sheet for cleaning the mold surface (when molded as it is without any release agent, the molded product adheres to the mold surface and does not release. The following is a description of a mold regenerating sheet for applying a release agent to the sheet. In other words, this kind of mold reproducing sheet, in place of the glycol ethers of the mold reproduction sheet for the purpose of cleaning the mold surface containing the release agent. Examples of this type of release agent include long-chain fatty acids such as stearic acid and behenic acid, metal salts of long-chain fatty acids represented by zinc stearate and calcium stearate, carnauba wax, montan wax, and montanic acid. Examples thereof include ester waxes represented by partially saponified esters, long-chain fatty acid amides represented by stearylethylenediamide, paraffins represented by polyethylene wax, and the like. The sheet for mold regeneration can be obtained by mixing the release agent and the unvulcanized rubber by a known method, for example, using a calender roll or the like. It can also be obtained by making dough and kneading a release agent into it. In these cases, the release agent is usually blended in an amount of 1 to 50 parts with respect to 100 parts of the unvulcanized rubber material. Preferred is 3 to 20 parts. The release agent preferably has a melting point of 200 ° C. or less and a boiling point of 200 ° C. or more. Further, those having a melting point of 50 to 150 ° C. are preferred. That is, molding is usually performed at 150 to 200 ° C., and the melting point of the release agent is 2
If it is higher than 00 ° C., it does not exude to the mold surface, and if it has a boiling point of less than 200 ° C., it tends to evaporate even if it exudes to the mold, so that it tends to lose its function. The unvulcanized rubber material in the mold regeneration sheet is mixed with other additives such as silica in the same manner as in the mold surface cleaning mold regeneration sheet. Is possible. Next, another specific example of the sheet for mold regeneration will be described. [Specific Example B] The raw materials shown in Tables 3 and 4 described below were blended, and this was rolled to a thickness of 7 using a rolling roll.
The sheet was formed into a sheet having a width of 10 mm, and a notch having a width of 10 mm and a depth of 5 mm was formed in a stripe shape in parallel with the width direction of the sheet to obtain a sheet for mold regeneration. [Table 3] [Table 4] The release sheet obtained as described above is folded from the above-mentioned mark so as to fit the molds of several types of transfer molding machines having different mold dimensions to have appropriate dimensions, and this is used to clean the mold surface. After the vulcanization, the mixture was vulcanized at 175 ° C. for 4 minutes, immediately after vulcanization, the mold was opened, and the molded vulcanized rubber was taken out. Thereafter, using a mold provided with a release agent as described above, a thermosetting resin molding material epoxy resin molding material (manufactured by Nitto Denko Corporation, MP-10) is molded by a normal molding method,
The mold release state of the molded article was examined. The results are shown in Tables 3 and 4 in comparison with the results of the comparative example (one dummy shot). As is clear from Tables 3 and 4, according to the specific examples, it can be seen that extremely good releasability can be imparted. The sheet for mold regeneration according to the present invention has marks for cutting the sheet into appropriate dimensions on the sheet surface, and is used for several types of molds having different mold dimensions. In this case, it is possible to cut easily and accurately from the place of the mark. Therefore, it is possible to realize quick cleaning of the mold and application of the release agent. Further, the present invention utilizes a cut provided in the sheet in advance and can be bent therefrom to form a multilayer, so that there is an effect that cleaning failure can be prevented and work can be rationalized.

[Brief description of the drawings]     FIG.   1 is a perspective view showing one embodiment of the present invention.     FIG. 2   It is explanatory drawing of the cut part of this invention.     FIG. 3   It is explanatory drawing of the modification of a cut part.     FIG. 4   It is formation explanatory drawing of the notch.     FIG. 5   It is formation explanatory drawing of the notch.     FIG. 6   FIG. 3 is an explanatory view of a use state of one embodiment of the present invention.     FIG. 7   It is explanatory drawing of a conventional example.     FIG. 8   It is explanatory drawing of a conventional example.     [Explanation of symbols] 10 sheets 11 landmarks

Claims (1)

Claims 1. An unvulcanized rubber base material containing no imidazole or imidazoline is used as a base material, and a plurality of linear marks for cutting the sheet into appropriate dimensions are provided on the sheet surface. A mold regenerating sheet, which is provided in parallel, and is formed by notches that can be cut from the mark portions. 2. The mold recycling sheet according to claim 1, wherein the unvulcanized rubber material contains a glycol ether. 3. The sheet according to claim 1, wherein the unvulcanized rubber material contains a release agent.