JPS63227308A - Sheet for reprocessing mold - Google Patents

Abstract

PURPOSE:To carry out cutting accurately and easily, by using an unvulcanized rubber raw sheet as a base material and setting marks for cutting a sheet into a suitable dimension on the sheet surface at specified distances. CONSTITUTION:An unvulcanized rubber raw sheet or the one composed of glycol ethers and an unvulcanized rubber is used as a base material. Instead of the above-described glycol ethers, imidazoles or/and imidazolines can be used. It is also possible to combine silica and alumina as a reinforcing agent with the above-described unvulcanized rubber. It is also possible to combine a releasing agent with them. Marks 11 for cutting a sheet 10 into a suitable dimension are set at specified distances. The above-described marks 11 are formed by notches and the depth of the notches are for example set at about 2/3 of the thickness of the sheet 10. Formation of the notches like this is done for example by means of a ribbon slitter having disc-shaped blades 13 on a rotating shaft 12 at specified distances.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a metal used for cleaning and regenerating molds such as molds for thermosetting resin molding materials that have been contaminated by repeated molding operations. This relates to mold recycling sheets.

[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, and phenomena such as roughness will occur on the surface of the molded product, resulting in disadvantages such as lack of gloss on the surface of the molded product. 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 into a cavity 3 formed by an upper mold 1 and a lower mold 2 for transfer molding via a runner 5 with the pressing force of a plunger 4. Thereafter, as shown in FIG. 9, when the mold is opened and the molded article 7 is taken out, and this molding operation is repeated, an oxidation-degraded layer 7a of the mold release agent is formed in 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. In order to solve such problems, conventionally,
The stage at which the release agent oxidation-degraded layer 7a is formed (700 to 10
00 shot), a thermosetting melamine resin molding material is put into the mold and molded and cured, and the release agent oxidation-degraded layer 7a on the surface of the mold is integrated with the molded product 7,
The surface of the mold is cleaned by removing the molded product 7 with the oxidation-degraded layer 7a integrated therefrom from the mold. In this case, formalin is produced as a condensation product of the thermosetting melamine resin molding material, causing odor and the like, which deteriorates the working environment and causes a decrease in cleaning workability. In addition, to remove the burrs 8a attached around molding parts such as cavities, rub the area around the mold molding parts using a spatula or brush every 50 to 100 shots to remove adhered contaminants such as burrs. This is done by blowing it out with air. However, it is troublesome to clean the area around such a molding part using a spatula or a brush.

[Problem that the invention seeks to solve]

In order to remove the oxidation-degraded layer of the mold release agent on the surface of the mold as described above, the present inventors developed a sheet-shaped mold cleaning method using unvulcanized rubber fabric as a base material and containing glycol ethers therein. Mold cleaning using this sheet-like composition, which has been developed and has already been patented (Japanese Patent Application No. 61-252536), is carried out as follows. That is, the above-mentioned sheet-like composition is sandwiched between upper and lower molds, the sheet-like composition is brought into contact with the mold surface by the pressure during molding, and in this state, the above-mentioned sheet-like composition is pressed using the heat during molding. The entire sheet composition is heated and vulcanized to form a vulcanized rubber, and during this vulcanization, the oxidation-degraded layer of the mold release agent on the surface of the mold is integrated into the vulcanized rubber, and then the mold is opened. Afterwards, the sheet-like composition that has been made into vulcanized rubber and has high strength and high elasticity is peeled off from the mold, thereby peeling off the oxidation-degraded layer integrated with the sheet-like composition from the mold surface. This is done by When such a sheet composition is used, problems such as those when using a thermosetting melamine resin molding material as described above do not occur.
The surface of the mold is also cleaned to an initial mirror state, similar to cleaning using the melamine resin molding material. However, -
In addition, the dimensions of the molds used in transfer molding machines etc. vary depending on the manufacturer, so the sheet composition is also set to the dimensions of the largest of these, and when used, it is Cutting is done according to the eye size.

However, it is inaccurate to perform cutting by eye in this way, and in some cases, this may lead to an inconvenient situation in which the product is cut smaller than the mold size and becomes unusable. Another problem is that the cutting requires a lot of nerve, which causes a lot of fatigue.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a mold recycling sheet that can be accurately and easily cut.

[Means for solving problems]

In order to achieve the above object, the mold recycling sheet of the present invention uses unvulcanized rubber fabric as a base material, and marks are provided at predetermined intervals on the sheet surface for cutting the sheet into appropriate dimensions. The structure is as follows.

In other words, as a result of providing a mark on the sheet as described above, the sheet can be cut using the mark as a guide, and therefore, the sheet can be cut more accurately than when cutting by the conventional method. , and cutting becomes easier.

The mold recycling sheet of this invention has an unvulcanized rubber fabric as a base material, and as mentioned above, is used for cleaning the mold surface (cavity surface); One is for the purpose of cleaning around the cavity of the mold (around the molding part), and the other is the mold after cleaning to make it easier to release the molded product that is molded for the first time after cleaning the mold surface (cavity surface). There are three types of mold release agents whose purpose is to apply a mold release agent to a surface. All of these three types of mold recycling sheets are provided with marks 11 at predetermined intervals for cutting the sheet 10 into appropriate dimensions, as shown in FIG. 1, for example. In FIG. 1, the mark 11 is formed by a notch, the depth of which is 2/3 of the thickness of the sheet 10.
It is set to about. Then, the sheet 10 can be cut to an appropriate size using the notches. FIG. 2 shows how this cut is formed.

Note that instead of making the cuts up to about 2/3 of the thickness as described above, the cuts may be made up to about half the thickness as shown in FIG.

For example, the formation of such cuts may be performed using a ribbon slitter having disk-shaped cutting blades 13 at predetermined intervals on the rotating shaft 12, as shown in FIG. Alternatively, an embossing cutter having bead-shaped cutting blades 14 of an abacus 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 base pattern as 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. Note that when the marks are formed at regular intervals, the marks also function as a measure.

Next, the mold recycling sheet used for cleaning the mold surface (cavity surface) mentioned in (1) above will be explained.

There are two types of mold recycling sheets of this type.

The first type uses an unvulcanized rubber fabric as a base material, which is a mixture of glycol ethers represented by the general formula (1) and unvulcanized rubber.

R, O→CHt C11z Oh-Rt・・・・・・(
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 monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol motupyl ether, diethylene glycol diethyl ether, diethylene glycol propyl ether, diethylene glycol dibutyl ether, ethylene glycol monomethyl ether, Examples include 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 any one of nx l~2, Rt, and Rt is hydrogen, the other is an alkyl group having 1 to 4 carbon atoms, and
When Rt and Rz are both alkyl groups, the number of carbon atoms is 1
-4 alkyl groups are preferred. In addition, when n 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 decreases. There is a tendency for things to get worse.

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.

May be used in combination with organic solvents such as xylene,
When mixing with organic solvents, the amount of organic solvent is usually
100 glycol ethers! The quantity (hereinafter abbreviated as "parts") 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.

Examples of unvulcanized rubber include natural rubber (NR), chloroprene rubber (CR), butadiene rubber (BR), etryl rubber (NBR), and ethylene propylene terpolymer rubber (
EPT), ethylene propylene rubber (EPM), styrene butadiene rubber (SBR), polyisoprene rubber (I
R), butyl rubber (IIR), silicone rubber (Q
), fluororubber (FKM), etc. alone or in combination as a main component, a vulcanizing agent is further blended, and if necessary, a vulcanization accelerator, a reinforcing agent, etc. are blended. This unvulcanized rubber is vulcanized in the mold to become vulcanized rubber. Preferred as the above unvulcanized rubber is EPT,
SBR, NBR or a mixture thereof. E above
PT is a copolymer consisting of ethylene, an α-olefin, and a cyclic or acyclic copolymer having a nonconjugated double bond.

To explain this in detail, EPT is a terpolymer consisting of ethylene, α-olefin (especially propylene), and the polyene monomers listed below, and the polyene monomers include dicyclopentadiene, 1,5-cyclooctadiene, l, 1-cyclooctadiene, 1.
6-cyclodozocadiene, 1.7-cyclodozocadiene, 1,5.9-cyclododecatriene, 1.4-cyclohebutadiene, 1,4-cyclohexadiene, norbornadiene, methylene norbornene, 2-methylpenta These include diene-1,4,1,5-hexadiene, 1,6-hebutadiene, methyl-tetrahydroindene, and 1,4-hexadiene. The copolymerization ratio of each monomer is preferably 30-80 mol% for ethylene and 0.1-80 mol% for polyene.
It is a terpolymer in which the remainder is α-olefin at 20 mol%.

More preferred is one containing 30 to 60 mol% of ethylene. And Mooney viscosity MLI+4 (100℃)
As a specific example of the above-mentioned EPT, which preferably has a value of 20 to 70, Mitsui EPT4021. manufactured by Mitsui Petrochemical Industries, Ltd. Same 4
045. I can give you 4070. Also, S.B.
Suitable R is one having a styrene content of 15 to 30 mol % and a Mooney viscosity ML1.4 (100° C.) of 20 to 80, preferably 35 to 60. Specific examples include JSR-1502 and JSR-1507 manufactured by Japan Synthetic Rubber Co., Ltd. 177
I can give you an 8. NBR has an acrylonitrile content of 20 to 60 mol%, preferably 25 to 45 mol%.
Mooney viscosity MLI-4 (100°C) in mol% is 20~
85, preferably 30 to 70. A specific example is N-234L manufactured by Japan Synthetic Rubber Co., Ltd.
, 230 S.

23t) SH can be raised.

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%
The amount is usually 10 to 60 parts, preferably 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 carried out at 150 to 185°C, and if the boiling point of the glycol ether is less than 130°C, evaporation during cleaning will be significant, and there is a risk that the cleaning work environment will deteriorate. On the other hand, if the temperature exceeds 250°C, it becomes difficult to evaporate and remains in the vulcanized rubber, which weakens the strength of the vulcanized rubber and causes it to collapse when taken out of the mold. This is because it becomes difficult to sufficiently peel off the oxidation-degraded layer of the mold release agent from the mold surface, which tends to reduce cleaning workability.

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 mold release agent include stearic acid, zinc stearate, carnauba wax, montan wax, stearyl ethylene diamide, and the like. 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 surface cleaning mold regenerating sheets described in item (1) above uses one or both of imidazoles and imidazolines in place of the above-mentioned glycol ethers. Other than that, it is exactly the same as the mold recycling sheet described above.

As the above-mentioned imidazoles, the use of imidazoles represented by the following general formula () gives good results. Representative examples of such imidazoles include 2-methylimidazole and 2-ethyl-4-methylimidazole. ,
2-phenylimidazole, 1-benzyl-2-methylimidazole, etc., 2,4-diamino-6 [2'-methylimidazolyl (1)') ethyl-5-triazine, 2,4-diamino-6 [2'] -ethyl-4'-methylimidazolyl-(1)')ethyl-5-1-riazine and the like.

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-phenylimidapurine, 1-benzyl-2
-Methylimidazoline, 2-phenyl-4-methyl-5
-Hydroxymethylimidazoline, 2,4-diamino-
6[2゛methylimidazolylyl(1)')ethyl-
3-triazine, 2,4-diamino-6[2°-methyl-4°-ethylimidasilylyru(1)')ethyl-S-triazine, 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]

After kneading the rubber shown in Table 1 below and the raw materials shown in the same table using a kneading roll, a rolling roll was used to form a sheet with a thickness of 7 days. Cuts 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 upper mold 1 and 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 were mixed in the proportions shown in the same table, kneaded with a kneading roll, formed into a sheet with a thickness of 71 m using a rolling roll, and marks of 10 square square base marks were formed by printing. .

(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 surface cleaning mold recycling sheet described in (2) above, and it uses an unvulcanized rubber fabric base material on the surface of a sheet-like fiber base material. It is formed in a layer on one or both of the mold surface and the back surface, and is finished with a thickness of about 0.2 to 1.0 ms, which is extremely thin 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 paper, inorganic fiber nonwoven fabrics such as glass fiber nonwoven fabrics, cellulose-mixed glass paper, and paper. Examples include materials. In some cases, there is no problem in using a woven fabric instead of the above-mentioned non-woven fabric. As an example of the above-mentioned non-woven fabric, a non-woven fabric made of polyester fibers is IEL E1030. made by Asahi Kasei Corporation. E1050,E
D-3038, D-30 manufactured by Itochu Corporation are used as fabric 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 and integrating.

Next, a specific example of the mold recycling sheet used for cleaning the area around the mold forming part (1) 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 0.5 m using a calender roll, and printed with a thickness of 10 m.
It formed a landmark for the base of Tsurugaku.

(Margin) East - ≦ 1 sp *: Good ... Wax B's theory ■ It is in the mirror state of the turning power period.

Defective: The damaged gel cannot be removed and remains dirty (margin) The sheet for mold recycling obtained as above is adapted to transfer molding with several types of mold dimensions. I cut it with a knife from the printed mark and finished it to the appropriate size. 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 the specific product has excellent performance.

Next, the mold surface was cleaned using a mold recycling sheet for mold surface cleaning (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 from the mold) ) The sheet for recycling molds (ii) whose purpose is to apply a mold release agent to molds will be explained. That is, this type of mold recycling sheet contains a mold release agent in place of the glycol ethers and imidazoles of the mold recycling 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.

Metal salts of long chain fatty acids represented by calcium stearate, ester waxes represented by carnauba wax, montan wax, partially saponified esters of montanic acid, long chain fatty acid amides represented by stearyl ethylene diamide, and polyethylene waxes. Examples include paraffins and the like.

This mold recycling sheet can be obtained by mixing the above-mentioned mold 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 mold release agent is
It is usually blended in 1 to 50 parts per 100 parts of unvulcanized rubber dough. The preferred amount is 3 to 20 parts. The above mold release agent preferably has a melting point of 200°C or lower and a boiling point of 200°C or higher. Further, preferred is one having a melting point of 50 to 150°C. That is,
Mold molding is usually carried out 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 boiling point is lower than 200°C, it will not ooze out into the mold surface. This is because even if it oozes into the mold, it will evaporate and the amount of f spray will no longer function.

In addition, other additives such as silica can be similarly blended into the unvulcanized rubber fabric in the mold recycling sheet described above, as in the mold surface cleaning mold recycling sheet described above. be.

Next, a specific example of this mold recycling 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 71 cm using a rolling roll, and form stripes with a width of 101 cm and a depth of 5 squares parallel to the width direction of the sheet. A mold recycling sheet was obtained.

(Hereafter, margin) (Hereafter, margin) 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 then used. Place it between the thermosetting resin molding molds whose mold surfaces have been cleaned, 17
Vulcanization was carried out at 5° C. for 4 minutes, and immediately after vulcanization, the mold was opened and 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 the results of the comparative example (1 dummy shot)
The comparison is shown in Table 4 above.

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

〔Effect of the invention〕

The mold recycling sheet of the present invention has marks on the sheet surface at predetermined intervals for cutting the sheet into appropriate dimensions, so when used for several types of molds with different mold dimensions, the above marks It can be easily and accurately cut from any point. Therefore, it becomes possible to speed up the work of cleaning the mold and applying a mold release agent.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the notch portion, FIG. 3 is an explanatory diagram of a modification of the notch portion, and FIGS. 4 and 5 are the formation of the notch. Explanatory drawings, FIG. 6 is an explanatory diagram of the usage state of one embodiment of the present invention, FIG. 7 is an explanatory diagram of the usage state of another embodiment, and FIGS. 8 and 9
The figure is an explanatory diagram of a conventional example. 10... Sheet 11... Marker Figure 1 Figure 2 Figure 2 04 Figure 05

Claims (6)

[Claims] (1) A sheet for mold recycling, which uses unvulcanized rubber dough as a base material and has marks on the sheet surface at predetermined intervals for cutting the sheet into appropriate dimensions. (2) The mold recycling sheet according to claim 1, wherein the unvulcanized rubber dough contains glycol ethers. (3) The mold recycling sheet according to claim 1, wherein the unvulcanized rubber dough contains at least one of imidazole and imidazolines. (4) The mold recycling sheet according to claim 1, wherein the unvulcanized rubber dough contains a mold release agent. (5) The mold recycling sheet according to claim 1, wherein the unvulcanized rubber base material is provided on at least one of the front and back surfaces of the sheet-like fiber base material. (6) Claim 1 in which the mark is made so that it can be cut from the mark part by making a notch.
The sheet for mold recycling according to any one of Items 1 to 5.