JP3993785B2 - Unvulcanized rubber sheet for rubber-laminated laminate and method for producing rubber-laminated laminate - Google Patents

Description

【００３８】
【発明の効果】
以上のように、この発明に係る未加硫ゴムシートによれば、ゴムシートとフェノール樹脂含浸プリプレグとの密着性が良好で、厚み寸法精度に優れたゴム貼積層板を効率よく製造することができる。従って、従来よりも作業コスト、ひいては製品コストの低コスト化を実現することができるという効果がある。
【図面の簡単な説明】
【図１】 この発明に係るゴム貼積層板を作製する際に、一対の熱盤間にステンレス製の鏡面仕上げ板を挟んで被加工体を配置した状態の概略図
【符号の説明】
１ 熱盤
２ ステンレス製の鏡面仕上げ板
３ 被加工体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rubber-clad laminate mainly used for packing for sealing a case opening of an electrolytic capacitor, an unvulcanized rubber sheet for producing this rubber-clad laminate, and a method for producing a rubber-clad laminate. .
[0002]
[Prior art]
An electrolytic capacitor usually includes a case, a capacitor element accommodated in the case, an electrolyte impregnated in the capacitor element, a packing that seals the opening of the case and prevents evaporation of the electrolyte, and a capacitor The lead is drawn from the element and penetrates the packing.
[0003]
Conventionally, as a method for producing the packing, a paper material is prepared by superimposing a prepreg impregnated with a phenolic resin and a vulcanized rubber sheet, and heating and pressurizing, and a vulcanized rubber sheet is not used. There is a method in which a vulcanized rubber sheet is used, and a prepreg in which a paper material is impregnated with a phenol resin and an unvulcanized rubber sheet are superposed on each other.
[0004]
In the method using a vulcanized rubber sheet, since the rubber sheet has already been vulcanized, a work piece in which a prepreg impregnated with a phenol resin in a paper material and a vulcanized rubber sheet are overlapped is placed in a press molding machine. Even if a plurality of sheets are inserted between a pair of hot plates and heated and pressed, there is no flow of the rubber component at the time of heat and pressure molding, and a rubber-laminated laminate with high thickness accuracy can be obtained.
[0005]
However, because the adhesion between the vulcanized rubber sheet and the phenolic resin impregnated prepreg is poor, the surface treatment of the vulcanized rubber sheet requires a surface treatment process such as irradiation with ultraviolet rays or electronic heat. There are disadvantages inferior to In addition, there is a disadvantage in that productivity is reduced because a separate process of heating and pressurizing the unvulcanized rubber sheet with, for example, a press molding machine is required.
[0006]
On the other hand, in the case of a method of using an unvulcanized rubber sheet, stacking an unvulcanized rubber sheet and a phenol resin-impregnated prepreg, and heating and pressurizing, at the interface between the unvulcanized rubber sheet and the phenol resin-impregnated prepreg The unvulcanized rubber component and the uncured phenol resin component are properly mixed, and the vulcanized rubber sheet and the phenol resin impregnated prepreg required for preventing electrolyte leakage required for the capacitor packing are strong. Adhesion can be obtained. Further, since the unvulcanized rubber sheet and the phenol resin impregnated prepreg are overlapped and manufactured by heating and pressurizing, a surface treatment process of the unvulcanized rubber sheet and a heating and pressing process for vulcanization are not required, Productivity is high.
[0007]
However, the unvulcanized rubber sheet has a flow of the unvulcanized rubber component during heat-pressure molding due to softening and molding pressure due to heat softening and molding pressure under molding conditions in which a commonly used phenol resin-impregnated prepreg is heated and pressurized. It is difficult to produce a rubber-laminated laminate with excellent thickness accuracy.
[0008]
For this reason, conventionally, a mold is used to prevent the unvulcanized rubber from flowing out in the heat and pressure molding process, or the rubber vulcanization conditions under which the unvulcanized rubber does not flow out under the heat and pressure conditions, and phenol resin curing It has been proposed to divide the condition into two stages (Japanese Patent Laid-Open No. 8-309777).
[0009]
However, in the method using a mold, the installation of the mold and the demolding process from the mold are required, resulting in poor productivity. In the method of dividing the heating and pressing conditions into two stages, when a plurality of these workpieces are inserted between a pair of heating plates in the press molding machine and heated and pressurized, the workpieces close to the heating plate and the heat Since a difference in heat conduction speed occurs between the workpiece away from the board and the workpiece closer to the hot board and the workpiece away from the hot board, the same heating and pressing conditions are used. I can't. For this reason, if the number of workpieces is single or plural between the hot plates, there is a disadvantage that the plate thickness accuracy is inferior.
[0010]
Thus, in any of the methods, it has been difficult to efficiently produce a rubber-laminated laminate having excellent adhesion between the rubber sheet and the phenol resin substrate and thickness dimensional accuracy.
[0011]
[Problems to be solved by the invention]
Therefore, the present invention provides an unvulcanized rubber sheet for producing a rubber-clad laminate capable of efficiently producing a rubber-clad laminate having excellent adhesion and thickness dimensional accuracy between the rubber sheet and the phenolic resin substrate, An object of the present invention is to provide a method for producing a rubber-laminated laminate using an unvulcanized rubber sheet.
[0012]
[Means for Solving the Problems]
The present invention pays attention to the Mooney viscosity and vulcanization speed of the unvulcanized rubber sheet, the Mooney viscosity (ML _{1 + 4} 100 ° C.) is 85 to 160, and the curastometer vulcanization rate index (t _{Δ 80} 130 ° C.). It has been found that an unvulcanized rubber sheet of 15 to 30 minutes can be integrally molded under heating and pressing conditions during curing of a commonly used phenolic resin and can suppress the flow of rubber components during heating and pressing. Is.
[0013]
That is, an unvulcanized rubber sheet having a Mooney viscosity (ML _{1 + 4} 100 ° C.) of 85 to 160 and a curastometer vulcanization rate index (t _{Δ 80} 130 ° C.) of 15 to 30 minutes, a phenol resin impregnated prepreg, The work piece with a laminated structure is a rubber-laminated laminate with excellent adhesion and thickness accuracy, with no flow of rubber components even if it is integrally molded under a one-step heating and pressing condition between hot plates in a press molding machine. can get. Moreover, since a plurality of the workpieces can be inserted between a pair of hot plates in a press molding machine and molded, a rubber-laminated laminate can be produced with high production efficiency.
[0014]
The unvulcanized rubber sheet according to the present invention is reduced by one minute by half with respect to 100 parts by weight of an ethylene-propylene-nonconjugated diene rubber (hereinafter referred to as “EPDM”) having a Mooney viscosity (ML _{1 + 4} 100 ° C.) of 60 to 110. It can be obtained by containing 1 to 8 parts by weight of organic peroxide having a period of 130 ° C. to 160 ° C. and 10 to 80 parts by weight of hydrous silicic acid.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
As described above, the unvulcanized rubber sheet according to the present invention has a Mooney viscosity (ML _{1 + 4} 100 ° C.) of 85 to 160, and a curastometer vulcanization rate index (t _{Δ 80} 130 ° C.) of 15 to 30. Is for the minute.
[0016]
The Mooney viscosity and the curastometer vulcanization rate index are defined in the unvulcanized rubber physical test method (JIS K6300). Mooney viscosity (ML _{1 + 4} 100 ° C.) indicates Mooney viscosity at 100 ° C., using a large rotor, 1 minute after preheating and further 4 minutes later. Curelastometer vulcanization rate index _(t Δ ₈₀ 130 ℃) is vulcanized at 130 ℃, 10% M _E the difference in minimum values M _L and the maximum value M _H of the torque as M _E, 90% M _E The respective arrival times t _{C (10)} and t _{C (90)} are taken and further expressed by t _{C (90)} -t _{C (10)} = t _{C (80)} . When the Mooney viscosity (ML _{1 + 4} 100 ° C.) is less than 85, the flow of the rubber component at the time of heat and pressure molding is reduced even if the curastometer vulcanization rate index (t _{Δ 80} 130 ° C.) is 15 to 30 minutes. It cannot be suppressed. When the Mooney viscosity (ML _{1 + 4} 100 ° C.) exceeds 160, it becomes difficult to form an unvulcanized rubber sheet.
[0017]
When the curastometer vulcanization rate index (t _{Δ 80} 130 ° C.) is less than 15 minutes, the vulcanization of the unvulcanized rubber is completed prior to the curing of the phenol resin-impregnated prepreg, and the substrate and the rubber sheet Adhesion with is poor. Further, when the curastometer vulcanization rate index (t _{Δ 80} 130 ° C.) exceeds 30 minutes, even when the Mooney viscosity (ML _{1 + 4} 100 ° C.) is 85 to 160, the heat during the press temperature rise. Due to the temperature difference due to the heat transfer degree between the board side and the center part, rubber vulcanization at the position farthest from the heating board is delayed, and the flow of the rubber component cannot be suppressed.
[0018]
The EPDM used in the present invention is a three-element polymer of ethylene, propylene and some diene components, and dicyclopentadiene, ethylidene norbornene, 1,4-hexadiene, etc. are used as the diene component. To limit the EPDM Mooney viscosity (ML ₁ + 4 100 ℃) 60 to 110, in less than a Mooney viscosity (ML ₁ + 4 100 ℃) is 60, the outflow of rubber at the time of integral molding by heating and pressing An unvulcanized rubber sheet that can be suppressed cannot be obtained. On the other hand, when the Mooney viscosity (ML _{1 + 4} 100 ° C.) exceeds 110, the dispersion of hydrous silicic acid in the rubber becomes extremely poor, and it becomes difficult to form a sheet of unvulcanized rubber.
[0019]
Furthermore, in this invention, it is necessary to contain 1 to 8 parts by weight of an organic peroxide having a half-life of 130 ° C. to 160 ° C. and 10 to 80 parts by weight of hydrous silicic acid with respect to 100 parts by weight of the EPDM.
[0020]
The one-minute half-life of 130 ° C. to 160 ° C. indicates that the temperature at which the decomposition rate of the organic peroxide is 50% in one minute is 130 ° C. to 160 ° C. Organic peroxide is a vulcanizing agent necessary for vulcanizing unvulcanized rubber. Specific examples include benzoyl peroxide, parachlorobenzoyl peroxide, t-butyl peracetate, 1,1-bis ( t-butylberoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t-butylberoxy) cyclododecane and the like.
[0021]
The amount of the organic peroxide is limited to 1 to 8 parts by weight. If the organic peroxide is less than 1 part by weight, the vulcanization is insufficient. If the amount exceeds 8 parts by weight, the capacitor packing is used. The necessary rubber elasticity is reduced.
[0022]
Hydrous silicic acid is SiO ₂ 80 to 90% containing crystal water and is used for suppressing the flow of unvulcanized rubber components. The mixing ratio of the hydrous silicic acid is limited to 10 to 80 parts by weight. If the mixing ratio of the hydrous silicic acid is less than 10 parts by weight, the effect of suppressing the flow of the unvulcanized rubber component cannot be obtained. This is because the dispersion of the rubber into the rubber is remarkably deteriorated and it becomes difficult to form a sheet of unvulcanized rubber.
[0023]
The unvulcanized rubber sheet according to the present invention includes various additives in addition to the above-mentioned blends, for example, co-vulcanizing agents such as sulfur and metal compounds other than organic peroxides; guanidines, thioureas, thiazoles, sulfur Vulcanization accelerators such as phenamides, thiurams, dithiocarbamates, xanthates; vulcanization retarders such as zinc white; antioxidants such as antioxidants and ultraviolet absorbers; carbon black, calcium silicate, Reinforcing agents such as aluminum silicate and clay; fillers or extenders such as calcium carbonate, talc, barium sulfate, aluminum sulfate, ritbon, styrene resin, phenol resin, petroleum resin, recycled rubber; plasticizer; alkylphenol resin, coumarone-indene Tackifiers such as resins and rosin derivatives; stearic acid, metal stearate soap, wax, etc. Processing aids or lubricants; may contain a coloring agent.
[0024]
The content of the additive can be appropriately selected according to the characteristics of the rubber sheet.
[0025]
As a blending method, a method generally used in the rubber processing field, for example, a kneading method using a mixing roll, a Banbury mixer, or various kneaders can be used.
[0026]
The unvulcanized rubber sheet may be processed using an open roll, a calender roll, and various extrusion molding methods. The thickness of the unvulcanized rubber sheet can be appropriately set according to the use of the rubber-laminated laminate, but is usually about 1 to 2 mm when used as a capacitor packing.
[0027]
The phenol resin-impregnated prepreg used by overlapping with the unvulcanized rubber sheet according to the present invention is obtained by impregnating a kraft paper with a phenol resin varnish produced by dehydration condensation reaction of carboxylic acid and formalin with an alkali catalyst, and drying the prepreg. Use the same thing.
[0028]
In the method for producing a rubber-clad laminate according to the present invention, the unvulcanized rubber sheet and the phenol resin-impregnated prepreg are overlapped to form a workpiece. A plurality of workpieces are inserted between a pair of heating plates in a press molding machine, and vulcanization of unvulcanized rubber sheets and curing of phenol resin impregnated prepregs of the workpieces are simultaneously performed under one-stage heating and pressing conditions. Complete and integrally mold to form a rubber-laminated laminate.
[0029]
The heating and pressurization conditions are appropriate conditions that do not impair the integrity of the rubber-laminated laminate, for example, a press pressure of about 30 to 70 kg / cm ² and a temperature of about 140 ° C. to 200 ° C. Good.
[0030]
【Example】
[Example 1]
(Production of phenol resin impregnated prepreg)
Kraft paper was impregnated with a resol-type phenolic resin varnish and dried to prepare a phenolic resin-impregnated prepreg, and a required number of prepregs were overlapped to prepare a workpiece made of only a phenolic resin-impregnated prepreg.
(Preparation of unvulcanized rubber composition and unvulcanized rubber sheet)
The unvulcanized rubber composition consisting of the following (1) to (8) was kneaded for 40 minutes using an open roll to prepare a sheet having a thickness of 1.0 mm.
( ₁ ) Mooney viscosity (ML _{1 + 4} 100 ° C.) 47 ethylene-propylene-nonconjugated diene rubber (manufactured by Sumitomo Chemical Co., Ltd., trade name: ESPREN EPDM522) (2) 1 minute half-life of 149 ° C. Organic peroxide (t-butyl peroxide) -3,3,5-trimethylcyclohexane (Nippon Yushi Co., Ltd., trade name: Perhexa 3M) 5 parts by weight (3) Hydrous silicon (Nippon Silica Kogyo Co., Ltd.) Product name: Nipseal VN3) 40 parts by weight (4) Carbon black (manufactured by Asahi Carbon Co., Ltd., trade name: Asahi 35 (SRF)) as reinforcing material 20 parts by weight (5) Sulfur as a co-vulcanizing agent 0.3 weight Part 6: 5 parts by weight of zinc white as a vulcanization aid (manufactured by Shodo Chemical Industry Co., Ltd.) 7 part of processing agent and 1 part by weight of stearic acid (manufactured by NOF Corporation) 8 ▼ A as a tackifier Kill phenolic resin (available from Nippon Kasei Chemical Industry Co., Ltd., trade name: Hitanoru 1501) 4 parts by weight (Preparation of rubber clad laminate)
A stainless steel mirror-finished plate in which the unvulcanized rubber sheet is superposed on the surface of the workpiece made of only the phenol resin-impregnated prepreg to further form the workpiece, and alternately treated with a release agent as shown in FIG. 5 sheets inserted between a pair of hot plates in a press molding machine, heated at a temperature of 160 ° C. and a pressure of 50 kg / cm ² for 90 minutes, and then cold pressed at the same pressure for 45 minutes to obtain a thickness. A 2.5 mm rubber-laminated laminate was produced.
[0031]
In FIG. 1, reference numeral 1 denotes a heating plate, 2 denotes a stainless steel mirror-finished plate, and 3 denotes a workpiece.
[0032]
(Evaluation)
Mooney viscosity was measured using a rotor in accordance with a physical test method for unvulcanized rubber (JIS K6300).
The curast meter vulcanization rate index was measured using a curast meter (manufactured by Nippon Gosho Co., Ltd., V type) under the condition of 130 ° C. in accordance with an unvulcanized rubber physical test method (JIS K6300).
-Adhesion strength was measured using a tensile tester (manufactured by Ueshima Seisakusho, shopper type) under the conditions of 90 ° peeling and a tensile speed of 50 mm / min after cutting the obtained rubber-laminated laminate into a 1 cm wide strip. .
-As for the thickness accuracy of the obtained rubber-laminated laminate, the difference between the maximum value and the minimum value of the measured thickness values was defined as the thickness accuracy in both the examples and comparative examples.
[0033]
[Example 2]
Mooney viscosity comprising 20% by weight of ethylene-propylene-nonconjugated diene rubber (manufactured by Sumitomo Chemical Co., Ltd., trade name: ESPREN EPDM524) having an EPDM of 80% by weight and a Mooney viscosity (ML _{1 + 4} 100 ° C.) of 35 of Example 1 (ML _{1 + 4} 100 ° C.) The same procedure as in Example 1 was performed except that 100 parts by weight of EPDM of 72 was used.
[0034]
[Comparative Example 1]
Instead of the EPDM of Example 1, except that 100 parts by weight of an ethylene-propylene-nonconjugated diene rubber having a Mooney viscosity (ML _{1 + 4} 100 ° C.) of 47 (manufactured by Sumitomo Chemical Co., Ltd., trade name: ESPREN EPDM522) is used. The same operation as in Example 1 was performed.
[0035]
[Comparative Example 2]
Instead of the organic peroxide (t-butyl peroxide) -3,3,5-trimethylcyclohexane of Example 1, the organic peroxide 2,5-dimethyl (2-ethylhexanoyl peroxy) with a 1 minute half-life of 112 ° C. It carried out similarly to Example 1 except using 5 weight part of hexane (Nippon Yushi Co., Ltd. product name: Perhexa250).
[0036]
[Comparative Example 3]
Instead of the organic peroxide (t-butyl peroxide) -3,3,5-trimethylcyclohexane of Example 1, the organic peroxide t-butyl peroxycumene (manufactured by NOF Corporation) with a half-life of 173 ° C. , Trade name: perbutyl C) The same procedure as in Example 1 was conducted except that 5 parts by weight were used.
The results are shown in Table 1.
[0037]
[Table 1]

[0038]
【The invention's effect】
As described above, according to the unvulcanized rubber sheet according to the present invention, it is possible to efficiently produce a rubber-clad laminate having good adhesion between the rubber sheet and the phenol resin-impregnated prepreg and having excellent thickness dimensional accuracy. it can. Therefore, there is an effect that it is possible to realize a reduction in work cost and thus product cost as compared with the conventional case.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a state in which a workpiece is placed with a stainless steel mirror-finished plate sandwiched between a pair of heating plates when producing a rubber-laminated laminate according to the present invention.
1 Hot plate 2 Stainless steel mirror finish plate 3 Workpiece

Claims (3)

Mooney viscosity (ML _{1 + 4} 100 ° C.) 60 to 110 ethylene-propylene-nonconjugated diene rubber 100 parts by weight 1 minute half-life of 1 to 8 parts by weight organic peroxide and hydrous silicic acid 10 Mooney viscosity consisting of those containing 80 parts by weight _{(ML 1 + 4 100 ℃)} 85~160, and Curelastometer vulcanization rate index (t _△ 80 130 ℃) unvulcanized rubber sheet and phenol is 15 to 30 minutes A rubber-laminated laminate in which a workpiece is formed by overlapping with a resin-impregnated prepreg, and is integrally molded by heating and pressing the workpiece. Mooney viscosity (ML _{1 + 4} 100 ° C.) 60 to 110 ethylene-propylene-nonconjugated diene rubber 100 parts by weight 1 minute half-life of 1 to 8 parts by weight organic peroxide and hydrous silicic acid 10 Mooney viscosity consisting of those containing 80 parts by weight _{(ML 1 + 4 100 ℃)} 85~160, and Curelastometer vulcanization rate index (t _△ 80 130 ℃) unvulcanized rubber sheet and phenol is 15 to 30 minutes A workpiece is formed by superposing resin-impregnated prepregs, and vulcanization of the unvulcanized rubber sheet of the workpiece and curing of the phenol resin-impregnated prepreg are performed in one stage between the heating plates in the press molding machine. A method for producing a rubber-laminated laminate that is completed in a single step and is integrally formed. 3. The rubber-laminated laminate according to claim 2 , wherein a plurality of workpieces in which the unvulcanized rubber sheet and the phenol resin-impregnated prepreg are overlapped are inserted between a pair of heating plates in a press molding machine. Method.

Images