JP3430897B2 - Prepreg and laminate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepreg used as a material for a printed wiring board and a laminated board composed of this prepreg.

[0002]

2. Description of the Related Art Conventionally, as a copper-clad laminate used for a printed wiring board, a glass cloth-base epoxy resin copper-clad laminate manufactured by using a prepreg having a glass cloth as a base material has been mainly used. However, in recent years, a number of printed wiring boards using an organic non-woven fabric have been proposed due to demands for weight reduction, low dielectric constant, laser hole processability in manufacturing process, and the like. As the fibers that make up this organic nonwoven fabric,
At present, many aramid fibers, which are excellent in heat resistance, are used.

However, the problem of the aramid fiber is that the surface of the fiber is extremely inactive and the adhesion with the resin to be impregnated is generally low. As a result, when an external force is applied to the pattern formed by copper foil or metal plating on the laminated plate, peeling occurs at the interface between the resin in the substrate and the base material, and the pattern peels off. This is confirmed, for example, in the case of the exterior pattern of the printed wiring board, the components mounted by soldering on the lands are detached, and in the case of the inner layer pattern, phenomena such as land cracks during through-hole processing are caused. .

As one of the effective means for solving this problem, there is a method of subjecting the surface of the substrate to plasma treatment under reduced pressure before impregnation with the resin. In this case, it is a well-known phenomenon that the surface of the fiber of the base material is activated and the adhesion to the resin is improved to some extent. When the plasma treatment is performed under reduced pressure, for example, the method shown in FIG. 3 is used. In the method shown in FIG. 3, first, a winding roll 15 obtained by winding a long aramid fiber non-woven fabric 4 into a roll is introduced into the decompression tank 22 and placed on one side of the plasma processing apparatus A ′ in the decompression tank 22. The nonwoven fabric 4 is unwound from the winding roll 15 and sent to the plasma processing apparatus A ′, and the plasma processing apparatus A ′ is arranged by the winding roll 23 arranged on one side opposite to the plasma processing apparatus A ′.
The non-woven fabric 4 is wound up from. The nonwoven fabric 4 wound around the winding roll 15 passes through the plasma processing apparatus A ′,
After being wound on the winding roll 3, the winding roll 23 is taken out from the decompression tank 22, and the nonwoven fabric 4 is unwound from the winding roll 23 and the container 1
The non-woven fabric 4 is impregnated with the resin varnish 19 continuously dipped in the resin varnish 19 stored in the inside 8. Then, the nonwoven fabric 4 impregnated with the resin varnish 19 is sent to the heating furnace 20,
The prepreg 21 is formed by being heated and dried while passing through the heating furnace 20 and being B-staged.

[0005]

However, there is a drawback in that the activity of the surface of the plasma-treated fiber is rapidly lost with the passage of time. In that respect, the plasma treatment is basically a batch treatment, and the plasma treatment is a plasma treatment. Under the present circumstances, a certain degree of surface deactivation is inevitable from the time of the resin to the resin impregnation. For example, in the case of the conventional example shown in FIG. 3, the nonwoven fabric 4 that has been subjected to the plasma treatment in the decompression tank 22 is impregnated with the resin varnish 19 after being wound on the winding roll 23. It takes time to impregnate the resin varnish 19.

The present invention has been made in view of the above points, in which the resin is impregnated while the effect of the plasma treatment on the aramid fiber is sufficiently maintained, resulting in sufficient adhesion between the aramid fiber and the resin. An object of the present invention is to provide a prepreg having high strength, and a laminated plate formed by using this prepreg, in which a conductor pattern formed on a substrate does not easily peel off.

[0007]

The prepreg according to the first aspect of the present invention is a B-stage in which a nonwoven fabric 4 made of aramid fiber is subjected to plasma treatment under normal pressure, impregnated with a thermosetting resin, and then heated. It is characterized by being formed. The invention described in claim 2 of the present invention is
In addition to the above constitution, in the above plasma treatment, as a reactive gas, a mixture of one or more of O ₂ , CO ₂ , N ₂ and NH ₃ is used.

In addition to the constitution of claim 1 or 2, the prepreg according to claim 3 of the present invention is obtained by immersing the non-woven fabric 4 plasma-treated under normal pressure in an aqueous solution of a silane coupling agent and heating it. It is characterized by being impregnated with a thermosetting resin after being dried. Further, the prepreg according to claim 4 of the present invention, in addition to the constitution of claim 1 or 2, is obtained by immersing the nonwoven fabric 4 that has been subjected to plasma treatment under normal pressure in an aqueous solution of an acrylic compound or a methacrylic compound,
It is characterized by being formed by impregnating a thermosetting resin after drying by heating.

A prepreg according to a fifth aspect of the present invention is characterized by using an epoxy resin as the thermosetting resin in addition to the structure according to any one of the first to fourth aspects. In addition to the constitution of claim 5, the prepreg according to claim 6 of the present invention is an epoxy resin epoxy which impregnates the nonwoven fabric with a compound having an amino group as a curing agent when the nonwoven fabric 4 is impregnated with epoxy resin. It is characterized in that the nonwoven fabric is impregnated with the NH equivalent ratio with respect to the equivalent in a range of 0.4 to 1.1.

Further, in the prepreg according to claim 7 of the present invention, in addition to the structure according to any one of claims 1 to 5, the amount of resin in the prepreg is 40 to 70 relative to the total amount of prepreg.
It is characterized in that it is% by weight. The prepreg according to claim 8 of the present invention is the nonwoven fabric 4 made of aramid fiber in addition to the structure according to any one of claims 1 to 7.
Is characterized by using a material having a density of 0.5 to 0.8 g / cm ³ .

Further, in the prepreg according to claim 9 of the present invention, in addition to the structure according to any one of claims 1 to 7, the steps from the plasma treatment to the impregnation of the thermosetting resin are continuously performed. It is characterized by being produced. A laminated plate according to a tenth aspect of the present invention is characterized in that the prepreg 21 according to any one of the first to ninth aspects and the metal foil are stacked and heat-pressed.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. The present invention uses a nonwoven fabric 4 made of aramid fiber. The aramid fiber is not particularly limited, but polyparaphenylene terephthalamide (PPTA) having a structural unit represented by the formula (A) below as a repeating unit, and formulas (A) and (B) below. It is possible to use copolyparaphenylene-3,4'-oxydiphenylene terephthalamide (PPODTA) composed of the structural unit represented by.

[0013]

[Chemical 1]

As the plasma treatment used in the present invention, different from the conventionally used low pressure plasma method, an atmospheric pressure plasma method capable of plasma discharge under normal temperature and normal pressure by introducing a dielectric layer into the electrode is used. To use. A method of performing plasma processing using plasma excited at room temperature and normal pressure will be described with reference to the drawings. FIG. 1 is a schematic diagram of a plasma processing apparatus A used in the present invention. As shown in FIG. 1, the plasma processing apparatus A includes an open reaction tank 1. A non-woven fabric inlet 13 for introducing the long non-woven fabric 4 into the reaction tank 1 is provided on one side of the reaction tank 1, and the long non-woven fabric 4 is drawn from the reaction tank 1 on the other side. A non-woven fabric outlet 14 is provided. A pair of planar electrodes 2 and 3 are arranged in the reaction tank 1 so as to face each other and be electrically insulated from the reaction tank 1. Of these, an upper electrode 2 arranged above is provided with an AC power source. 5 is connected, and the lower electrode 3 arranged below is grounded. A solid dielectric 6 is arranged on the surface of the lower electrode 3 facing the upper electrode 2. The space between the upper electrode 2 and the solid dielectric 6 is formed as a plasma zone 11. The solid dielectric 6 may be arranged on both surfaces of the lower electrode 3 and the upper electrode 2 facing each other. In this case, the space between the facing solid dielectrics 6 is formed as the plasma zone 11. It A feeding reel 16 (not shown in FIG. 2) is arranged on the side of the nonwoven fabric introduction port 13 of the reaction tank 1, and a winding reel 17 (not shown in FIG. 2) is arranged on the side of the nonwoven fabric outlet port 14. The non-woven fabric 4 is sent to the non-woven fabric inlet 13 of the reaction tank 1 by the feed reel 16 by using motor power and the non-woven fabric 4 is wound from the non-woven fabric outlet 14 of the reaction tank 1 by the winding reel 17. By taking it, the long non-woven fabric 4 is continuously introduced into the reaction tank 1 through the non-woven fabric inlet 13 and the non-woven fabric outlet 14
The nonwoven fabric 4 passes through the reaction tank 1 at a constant speed so that the nonwoven fabric 4 is continuously drawn from the reaction tank 1 to the outside of the reaction tank 1. By adjusting the winding speed, the passing speed of the nonwoven fabric 4 in the reaction tank 1 can be adjusted. The non-woven fabric 4 introduced into the reaction tank 1 through the non-woven fabric inlet 13 is designed to pass between the upper electrode 2 and the solid dielectric 6, and when passing through the reaction tank 1, the non-woven fabric is 4 is the upper electrode 2
And it is preferable not to contact with the solid dielectric 6. A thermocouple (not shown) is inserted in the reaction tank 1 so that the ambient temperature in the reaction tank 1 can be monitored.

On the other hand, outside the reaction tank 1, a carrier gas cylinder 9 in which a carrier gas is stored and a reactive gas cylinder 10 in which a reactive gas is stored are arranged. The carrier gas cylinder 9 and the reactive gas cylinder 10 are arranged. Is connected to the gas mixer 8, and the carrier gas and the reactive gas are mixed in the gas mixer 8. One end of the gas supply passage 12 is connected to the gas mixer 8, and the other end of the gas supply passage 12 is connected to the reaction tank 1 at the gas introduction port 7. The carrier gas and the reactive gas mixed therein are supplied from the gas inlet 7 into the reaction tank 1 through the gas supply passage 12.

When the plasma treatment apparatus A configured as described above is used to perform the plasma treatment on the nonwoven fabric 4 made of aramid fibers at room temperature and normal pressure, first, the carrier gas is supplied from the carrier gas cylinder 9 to the gas mixer. The gas is introduced from the gas inlet 7 into the reaction tank 1 through the gas supply passage 12 and the AC power supply 5 is operated to supply AC power to the upper electrode 2. The supplied AC power causes glow discharge between the upper electrode 2 and the lower electrode 3 to excite plasma. Here, under normal pressure, it is difficult to cause stable glow discharge and arc discharge easily, and it is difficult to uniformly excite plasma between the electrodes 2 and 3, but as described above. Since the solid dielectric 6 is arranged on the surface of the lower electrode 3 facing the upper electrode 2,
Due to the action of this solid dielectric 6, stable glow discharge can be generated between the upper electrode 2 and the lower electrode 3 even under normal pressure. In this state, the reactive gas is introduced from the reactive gas cylinder 10 through the gas mixer 8 into the reaction tank 1 through the gas inlet 7 together with the carrier gas, and the feeding reel 16 and the winding reel 17 are connected to a motor or the like. The non-woven fabric 4 is passed through the reaction tank 1 in the direction of the arrow in the figure by driving. At this time, the reactive gas and the carrier gas should have a predetermined amount by adjusting the flow rate.
The mixed gas of the reactive gas and the carrier gas is preferably introduced into the reaction tank 1 so that the mixed gas of the reactive gas and the carrier gas is blown onto the surface of the nonwoven fabric 4. In this way, the nonwoven fabric 4 passing through the reaction tank 1 is subjected to plasma treatment in the plasma zone 11 inside the reaction tank 1. Here, the plasma treatment time of the nonwoven fabric 4 is the time required for a certain point of the nonwoven fabric 4 to pass through the plasma zone 11, and the feeding speed of the nonwoven fabric 4 by the feeding reel 16 and the winding reel 17 is adjusted. Adjusted.

Hydroxyl groups are formed on the surface of the non-woven fabric 4 plasma-treated as described above, and the surface is activated. When the nonwoven fabric 4 is impregnated with the thermosetting resin in this state, the adhesion between the aramid fiber forming the nonwoven fabric 4 and the thermosetting resin is improved. Here, the hydroxyl groups on the surface of the non-woven fabric 4 get into the inside of the fibers constituting the non-woven fabric 4 with the passage of time, and the surface of the non-woven fabric 4 is deactivated. However, in the present invention, the plasma treatment is performed at room temperature and normal pressure. Therefore, unlike the case of low-pressure plasma treatment which is a batch treatment, the nonwoven fabric 4 can be impregnated with the thermosetting resin immediately after the plasma treatment, and the surface of the nonwoven fabric 4 activated by the plasma treatment is lost. The thermosetting resin can be impregnated before activation to improve the adhesion between the nonwoven fabric 4 and the resin. As a result of the research conducted by the inventors, it has become clear that the treatment efficiency of plasma treatment is more likely to be rapidly impaired than that of the surface of an inorganic material, and it is necessary to immediately enter a process such as resin impregnation from plasma treatment. It can be said that the atmospheric pressure plasma treatment of the present application which enables the above is a very effective means.

As the carrier gas used in the above plasma treatment, it is preferable to use helium gas or argon gas alone or to use a mixture thereof, and a small amount of a reactive gas is added to the carrier gas for plasma treatment. Introduce into reactor A. As the reactive gas, oxygen (O
₂ ), carbon dioxide (CO ₂ ), nitrogen (N ₂ ), and ammonia (NH ₃ ) have been found to have a large effect on plasma treatment, and one or more of these may be combined. Can be used. It is also possible to divide the reaction tank 1 of the plasma processing apparatus A into two stages, a first reaction tank and a second reaction tank, and use different reactive gases in each reaction tank 1. Although the amount of the reactive gas added to the carrier gas varies depending on the type of the reactive gas, it is preferably in the range of 0.5 to 15 vol% with respect to the carrier gas.
If it is less than 5 vol%, the effect of plasma treatment becomes small, and if it exceeds 15 vol%, the discharge may become unstable. The frequency of the AC power supplied from the AC power supply 5 to the upper electrode 2 to excite the plasma is 50 Hz to 1 Hz.
When it is set to 00 MHz, discharge is stable under normal pressure, which is preferable, and more preferably from 1 kHz to 13.5.
In the range of 6 MHz, the effect of plasma treatment becomes particularly large.

The prepreg 21 of the present invention can be obtained by impregnating the non-woven fabric 4 which has been subjected to the plasma treatment as described above with a thermosetting resin, and then heating and drying the B-stage. Here, the resin amount of the resin contained in the prepreg 21 is preferably 40 to 70 wt% with respect to the total amount of the prepreg. If the amount of resin is less than 40 wt%, the amount of resin in the laminated plate when the laminated plate is formed from this prepreg 21 becomes insufficient and voids or the like are generated in the laminated plate, which may cause a problem that moisture absorption becomes large. If the amount of resin exceeds 70 wt%, the thermal expansion of the laminated plate is greatly affected by the properties of the resin, and the coefficient of thermal expansion increases, and the original properties of aramid fiber, such as low thermal expansion, are lost. May occur.

[0020] Density of the nonwoven fabric 4 consisting of aramid fibers, there is preferably a 0.5~0.8g / cm ^3, when exceeds 0.8 g / cm ^3, the nonwoven fabric 4 to the inside The resin penetration may be impaired, voids may remain in the laminated plate after molding, and moisture absorption may increase.
If it is less than 5 g / cm ³ , on the contrary, the resin is completely taken into the nonwoven fabric 4, and the resin amount of the prepreg must be 70 wt% or more in order to secure sufficient moldability.
The thermal expansion of the laminated plate is greatly affected by the characteristics of the resin, and the coefficient of thermal expansion increases, which may cause a problem such as loss of low thermal expansion, which is the original characteristic of the aramid fiber.

In order to impregnate the non-woven fabric 4 with the thermosetting resin, a method of immersing the non-woven fabric 4 in a resin varnish 19 obtained by dissolving the thermosetting resin in an organic solvent or the like can be used. As the thermosetting resin, the cost is low, it is preferable to use an epoxy resin excellent in electrical insulation, or a polyimide resin excellent in heat resistance, and when using an epoxy resin as the thermosetting resin,
As the epoxy resin, for example, a bisphenol A type epoxy resin, a novolac type epoxy resin, or a halogenated novolac type epoxy resin having flame retardancy added thereto can be used. Further, the resin varnish 19 may contain an amino group-containing compound such as dicyandiamide, a novolac type curing agent such as phenol novolac, or the like, or a mixture of two or more thereof. The resin varnish 19 may contain imidazoles such as 2-ethyl-4-methylimidazole and tertiary amines such as dimethylbenzylamine as a curing accelerator. As a solvent for diluting these components, methyl ethyl ketone, dimethylformamide, acetone,
Methyl cellosolve, dioxane and the like can be used alone or in combination of two or more.

When an epoxy resin is used as the thermosetting resin, the effect of improving the adhesion between the resin and the non-woven fabric 4 can be sufficiently obtained even if a phenolic curing agent or the like is used as the curing agent. An amino group-containing compound such as dicyandiamide is added in an NH equivalent ratio to an epoxy equivalent of 0.4.
By blending the above, the adhesiveness between the resin and the nonwoven fabric 4 can be further improved, and the adhesiveness between the metal foil and the resin when the metal foil-clad laminate is formed using such a prepreg 21 is also improved. It will improve. In order to further improve such effects, an amino group-containing compound is blended in an NH equivalent ratio of 0.4 to 1.1 with respect to 1 equivalent of epoxy of the epoxy resin blended in the resin varnish 19. Is preferable. When a novolac type curing agent is used together with an amino group-containing compound as a curing agent, the OH of the novolac type curing agent is used.
It is preferable that the equivalent is blended in an equivalent ratio of 0.1 to 0.5 with respect to 1 equivalent of epoxy. Further, the curing accelerator is preferably blended in the range of 0.02 to 0.8 phr with respect to the total amount of the epoxy resin and the curing agent in the resin varnish 19. The amount of the solvent in the resin varnish 19 is not particularly limited, and may be any amount so long as it can ensure good impregnation of the non-woven fabric 4 with the resin.
The resin varnish 19 is blended so as to be about 10 to 80% by weight with respect to the total amount.

Further, the non-woven fabric 4 which has been subjected to the plasma treatment,
A treatment with a silane coupling agent can be performed before impregnation with the thermosetting resin. On the surface of the non-woven fabric 4 subjected to plasma treatment, a phenomenon that the hydrophilic group side of the silane coupling agent suitably causes a dehydration condensation reaction is observed, and if this phenomenon is utilized, the silane coupling agent may be selected depending on the selection of the silane coupling agent. The lipophilic base side and the thermosetting resin to be impregnated are well compatible or react with each other, whereby strong adhesion between the aramid fiber constituting the nonwoven fabric 4 and the impregnated resin can be obtained. Examples of the silane coupling agent include γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, γ-aminopropyltriethoxysilane. Ethoxysilane, γ-methacryloxypropylmethyldimethoxysilane and the like are preferably used. The nonwoven fabric 4 is treated by a wet treatment using such a silane coupling agent. The treatment conditions are, for example, 0.5 to 3% silane coupling agent aqueous solution, and ,
Impregnate the plasma-treated non-woven fabric 4 with 100 to 12
It is performed by heating and drying at about 0 ° C.

Further, the non-woven fabric 4 which has been subjected to the plasma treatment,
It is also possible to treat with an acrylic compound or a methacrylic compound before impregnating with a thermosetting resin. An acrylic group of an acrylic compound or a methacrylic compound is bonded to the surface of the non-woven fabric 4 which is plasma-treated by a reaction which seems to be a graft reaction, and as a result, the adhesion between the thermosetting resin and the non-woven fabric 4 can be improved. Is. As the acrylic compound or methacrylic compound, acrylamide, methyl acrylate, methyl methacrylate, or the like can be used, and the nonwoven fabric 4 is treated by a wet treatment, and the treatment condition is, for example, 2 to 10%. It is carried out by preparing an aqueous solution of an acrylic compound or a methacrylic compound to a certain degree, impregnating the aqueous solution with the plasma-treated nonwoven fabric 4, and heating and drying at about 70 to 100 ° C.

In manufacturing the prepreg 21 as described above, a continuous process as shown in FIG. 1 can be used. In the continuous process shown in FIG. 1, first, a long aramid fiber non-woven fabric 4 is rolled into a roll and is sent to the plasma processing apparatus A while unwinding the non-woven fabric 4. Here, the non-woven fabric inlet 13 of the plasma processing apparatus A
The feeding reel 16 is disposed on the side, and the winding reel 17 is disposed on the side of the nonwoven fabric outlet 14 so that the nonwoven fabric 4 is continuously fed to the plasma processing apparatus A by the feeding reel 16. The nonwoven fabric 4 is continuously drawn from the plasma processing apparatus A by the winding reel 17. The nonwoven fabric 4 drawn out from the plasma processing apparatus A is continuously immersed in the resin varnish 19 stored in the container 18 to impregnate the nonwoven fabric 4 with the resin varnish 19. The nonwoven fabric 4 impregnated with the resin varnish 19 is sent to the heating furnace 20,
While passing through the inside of the heating furnace 20, it is heated and dried, and is B-staged to form the prepreg 21. Here, a step of performing a treatment with a coupling agent or a treatment with a compound having an acrylic group is arranged in the passage of the non-woven fabric 4 between the plasma processing apparatus A and the container 18 to remove the treatment with the coupling agent or the acrylic group. The treatment with the compound may also be carried out continuously.

When a continuous process is used in the production of the prepreg 21 as described above, the plasma-treated nonwoven fabric 4 is used.
The thermosetting resin can be rapidly impregnated before the surface of the prepreg is deactivated, and the prepreg having the plasma treatment step can be efficiently produced. The laminated plate of the present invention is obtained by stacking one or more prepregs 21 of the present invention as described above to have a desired thickness, arranging metal foils such as copper foils on both sides of the prepregs 21, and heat-pressing. It is obtained by integrating with. The laminate thus formed has high adhesiveness between the non-woven fabric 4 made of aramid fiber and the resin, and therefore peeling is unlikely to occur at the interface between the resin and the non-woven fabric 4 in the laminate. When used as a printed wiring board,
The conductor pattern formed on the printed wiring board is less likely to come off. The adhesiveness between the non-woven fabric 4 of aramid fiber and the resin is prepreg 21 of the present invention.
Can be confirmed by measuring the copper foil peel strength when the copper foil-clad laminate is molded.

[0027]

EXAMPLES The present invention will be described in detail below with reference to examples. (Example 1) 10 parts by weight of cresol novolac type epoxy resin (manufactured by Tohto Kasei Co., Ltd., product number "YDCN-704"), brominated bisphenol A type epoxy resin (manufactured by Toto Kasei Co., Ltd., product number "YDB-500K") ) 3 parts by weight, 4 parts by weight of a phenol novolac resin (manufactured by Dainippon Ink and Chemicals, Inc., product number "LF4871") as a curing agent, 0.2 parts by weight of benzylmethylamine as a curing accelerator, and 50 parts by weight of methyl ethyl ketone as a solvent. By doing so, the epoxy resin varnish 19 was prepared.

Nonwoven fabric 4 made of aramid fiber, manufactured by DuPont, trade name "Cermount" (main component: polyparaphenylene terephthalamide, density: 0.55 g / cm3)
³ ) was used and the surface of the nonwoven fabric 4 was directly subjected to atmospheric pressure plasma treatment. The conditions of the plasma treatment were as follows. <Condition A> Gas used: carbon dioxide 4 vol%, helium 96 vol% Frequency of alternating current power: 5 kHz Applied power: 150 W Treatment time: 30 seconds Immediately after this plasma treatment step, the nonwoven fabric 4 was applied to the resin varnish 19 in a continuous step. Dipping and impregnation, 160 ℃
By performing a B-stage through a drying step for 7 minutes, a prepreg 21 having a resin amount of 60 wt% was obtained.

Five prepregs 21 are laminated, and copper foil having a thickness of 30 μm is arranged on both sides of the prepreg 21, 170 ° C., 30 kg.
/ Cm ² , for 120 minutes under heat and pressure molding, and integrated to obtain a double-sided copper foil-clad laminate. The copper foil peel strength of this double-sided copper foil-clad laminate was measured according to JIS-C6481. (Example 2) The same procedure as in Example 1 was carried out except that the plasma treatment conditions were as follows.

<Condition B> Gas used: 2 vol% of ammonia, 38 vol% of helium, 60 vol% of argon Frequency of AC power: 100 kHz Applied power: 100 W Treatment time: 20 seconds (Example 3) Nonwoven fabric 4 similar to Example 1 And resin varnish 19 were used.

The nonwoven fabric 4 was subjected to plasma treatment in the following treatment conditions in a plasma treatment apparatus having two reaction vessels 1 of a first reaction vessel and a second reaction vessel. <Condition C> First reaction tank Working gas: Ammonia 2 vol%, Helium 38 vol%, Argon 60 vol% AC power frequency: 100 kHz Applied power: 100 W Treatment time: 20 seconds Second reaction tank Working gas: Ammonia 2 vol% , Helium 38vol%, Argon 60vol% Frequency of AC power: 100kHz Applied power: 100W Treatment time: 20 seconds Immediately after the plasma treatment, the non-woven fabric 4 is γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., The product number "KBM-403") is continuously dipped in an aqueous solution containing 2% to impregnate it, and after the drying step at 120 ° C. for 5 minutes, the nonwoven fabric 4 is further dipped in the resin varnish 19 to be impregnated. It was

Otherwise, the same procedure as in Example 1 was carried out. (Example 4) The same nonwoven fabric 4 and resin varnish 19 as in Example 1 were used. The plasma treatment conditions were as follows. <Condition D> Gas used: 2 vol% nitrogen, 38 vol% helium, 60 vol% argon 60 vol% Frequency of AC power: 13.56 kHz Applied power: 200 W Treatment time: 20 seconds Immediately after the plasma treatment, 5% of acrylamide is left as it is. The non-woven fabric 4 was continuously dipped in the resin varnish 19 to be impregnated therein after a drying process at 110 ° C. for 5 minutes.

Otherwise, the same procedure as in Example 1 was carried out. (Example 5) As a resin varnish 19, a cresol novolac type epoxy resin (manufactured by Tohto Kasei Co., Ltd., product number "YDC")
N-704 ") 10 parts by weight, brominated bisphenol A type epoxy resin (manufactured by Tohto Kasei Co., Ltd., product number" YDB-50 "
0K ") 3 parts by weight, dicyandiamide as a curing agent 0.
5 parts by weight, benzylmethylamine as a curing accelerator 0.
The same procedure as in Example 2 was carried out except that 2 parts by weight and a solvent containing 50 parts by weight of methyl ethyl ketone were used. Here, the dicyandiamide has an NH equivalent of 0.1 with respect to the epoxy equivalent of the epoxy resin in the resin varnish 19.
It is compounded in an equivalent ratio of 7. (Example 6) The same procedure as in Example 3 was carried out except that the same resin varnish 19 as in Example 5 was used. (Example 7) As a resin varnish 19, a polyimide resin (manufactured by Ciba-Geigy, trade name "Kelimide 601") 1
Example 1 except that 100 parts by weight and a solvent containing 50 parts by weight of N-methylpyrrolidone were used and the drying conditions after impregnation with the resin varnish 19 were 170 ° C. and 5 minutes.
It carried out similarly to. (Example 8) as a nonwoven fabric 4 consisting of aramid fiber, manufactured by Oji Paper Co., Ltd., trade name "Technora" (main component: co polyparaphenylene-3,4'-oxydiphenylene terephthalamide, density: 0.72 g / cm ³ ) Was carried out in the same manner as in Example 1. (Example 9) The same procedure as in Example 2 was carried out except that as the non-woven fabric 4, "Technora" manufactured by Oji Paper Co., Ltd. was used. (Example 10) The same procedure as in Example 3 was carried out except that as the non-woven fabric 4, "Technora" manufactured by Oji Paper Co., Ltd. was used. (Comparative Example 1) The procedure of Example 1 was repeated except that the nonwoven fabric 4 was not subjected to plasma treatment. (Comparative Example 2) The procedure of Comparative Example 1 was repeated, except that as the non-woven fabric 4, "Technora" manufactured by Oji Paper Co., Ltd. was used. (Comparative Example 3) The same procedure as in Comparative Example 1 was carried out except that the plasma treatment was carried out by the depressurization treatment as shown below.

[0034] Gas used: carbon dioxide Pressure: 10 Torr Frequency of AC power: 13.56 kHz Applied power: 150W Processing time: 30 seconds The above results are shown in Table 1.

[0035]

[Table 1]

As can be seen from Table 1, in Examples 1 to 10 as compared with Comparative Examples 1 to 3, the copper foil peel strength was improved and it was confirmed that the adhesion between the nonwoven fabric 4 and the resin was improved. It was In addition, in Examples 1, 2 and 8 in which the nonwoven fabric 4 was not treated with the silane coupling agent or the acrylamide after the plasma treatment, the copper foil peels were performed in Examples 3 to 6 and Examples 9 and 10. The strength was improved, and the effects of the treatment with the silane coupling agent and the treatment with acrylamide were confirmed.

Further, in comparison with Examples 3 and 4 in which the resin varnish 19 contained an epoxy resin and contained no dicyandiamide, the NH equivalent was 0.7 in terms of the equivalent ratio to the epoxy resin and the epoxy equivalent of the epoxy resin. In Examples 5 and 6 using the one containing dicyandiamide, the copper foil peel strength was improved, and it was confirmed that the copper foil peel strength was improved as a result of using the resin varnish containing the epoxy resin and dicyandiamide. It was

[0038]

As described above, in the prepreg according to the first aspect of the present invention, the nonwoven fabric made of aramid fibers is subjected to plasma treatment under normal pressure, impregnated with the thermosetting resin, and then heated to be B-staged. Therefore, it is possible to continuously perform plasma treatment on the nonwoven fabric by plasma excited under normal pressure, and to impregnate the thermosetting resin immediately after performing the plasma treatment on the nonwoven fabric. The thermosetting resin can be impregnated before the surface of the formed nonwoven fabric is deactivated to improve the adhesion between the nonwoven fabric and the resin.

In addition to the constitution of claim 1, the prepreg according to claim 2 of the present invention has O ₂ , CO ₂ , N ₂ and NH ₃ as reactive gas in the above plasma treatment.
Since one or a mixture of two or more of them is used, plasma can be efficiently excited under normal pressure to perform the plasma treatment of the nonwoven fabric. Further, the prepreg according to claim 3 of the present invention, in addition to the configuration according to claim 1 or 2, is a nonwoven fabric that is plasma-treated under normal pressure,
Since the surface of the non-woven fabric treated with plasma and the hydrophilic group side of the silane coupling agent undergo a dehydration condensation reaction because the surface of the non-woven fabric subjected to plasma treatment is immersed in the aqueous solution of the silane coupling agent and dried by heating to impregnate the thermosetting resin, Covered with a ring agent, the lipophilic base side of the silane coupling agent on the surface of the non-woven fabric and the thermosetting resin to be impregnated are well compatible or react to obtain strong adhesion between the non-woven fabric and the impregnated resin. Is.

Further, in the prepreg according to claim 4 of the present invention, in addition to the constitution of claim 1 or 2, the nonwoven fabric plasma-treated under normal pressure is dipped in an aqueous solution of an acrylic compound or a methacrylic compound, Since the thermosetting resin is impregnated after drying by heating, the acrylic group of the acrylic compound or the methacrylic compound reacts with the surface of the plasma-treated nonwoven fabric to bond with it, resulting in a strong adhesion between the nonwoven fabric and the impregnated resin. It is what is done.

Further, in the prepreg according to claim 5 of the present invention, since the epoxy resin is used as the thermosetting resin in addition to the structure according to any one of claims 1 to 4, the cost of the prepreg can be reduced. In addition, the electrical insulation of the prepreg can be improved.
The prepreg according to claim 6 of the present invention is the prepreg according to claim 5.
In addition to the above constitution, when the nonwoven fabric is impregnated with the epoxy resin, the NH equivalent ratio to the epoxy equivalent of the epoxy resin with which the nonwoven fabric is impregnated with the compound having an amino group as a curing agent is in the range of 0.4 to 1.1. Since the non-woven fabric is impregnated, the adhesion between the resin and the non-woven fabric can be further improved, and the adhesion between the metal foil and the resin when forming the metal foil-clad laminate using such a prepreg is also improved. Is something that can be done.

Further, in the prepreg according to claim 7 of the present invention, in addition to the structure according to any one of claims 1 to 6, the amount of resin in the prepreg is 40 to 70 with respect to the total amount of prepreg.
Since it is wt%, the amount of resin in the laminated plate when forming the laminated plate from this prepreg does not become insufficient,
Voids and the like are not generated in the laminated plate to increase moisture absorption, and the thermal expansion of the laminated plate is not greatly affected by the characteristics of the resin and the coefficient of thermal expansion does not increase. The low thermal expansion, which is the original property of aramid fiber, is not lost.

The prepreg according to claim 8 of the present invention, in addition to the structure according to any one of claims 1 to 7, has a density of 0.5 to 0.8 g as a nonwoven fabric made of aramid fiber.
/ Cm ³ is used, the penetration of the resin into the inside of the nonwoven fabric is not impaired, voids do not remain in the laminated plate after molding, and moisture absorption is not likely to increase. Without being completely taken into the nonwoven fabric, the thermal expansion of the laminate is greatly affected by the properties of the resin and the coefficient of thermal expansion increases, and the low thermal expansion, which is the original property of aramid fiber, is lost. There is no fear.

The prepreg according to claim 9 of the present invention is obtained by performing the steps from the plasma treatment to the impregnation of the thermosetting resin in a continuous process in addition to the structure according to any one of claims 1 to 8. Since it is produced, it is possible to rapidly impregnate the thermosetting resin before the surface of the non-woven fabric subjected to the plasma treatment is deactivated, and the production of the prepreg having the process of the plasma treatment can be performed efficiently. It is something that can be done.

A laminated sheet according to a tenth aspect of the present invention comprises a non-woven fabric of aramid fiber and a resin for laminating the prepreg and the metal foil according to any one of the first to ninth aspects and heat-pressing them. The adhesiveness is high and peeling does not easily occur at the interface between the resin and the nonwoven fabric in the laminated board.When this laminated board is used as a printed wiring board, peeling of the conductor pattern formed on the printed wiring board occurs. It becomes difficult.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a manufacturing process for manufacturing a prepreg of the present invention.

FIG. 2 is a schematic sectional view showing the plasma processing apparatus of FIG.

FIG. 3 is a schematic view showing an example of a manufacturing process for manufacturing a conventional prepreg.

[Explanation of symbols]

4 non-woven fabric 21 prepreg

Front page continuation (51) Int.Cl. ⁷ Identification code FI // C08L 63:00 C08L 63:00 79:08 79:08 (72) Inventor Koichi Ito 1048, Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. (56) Reference JP-A-63-35630 (JP, A) JP-A-61-174231 (JP, A) JP-A-61-174230 (JP, A) JP-A-9-143285 (JP, A) JP-A-8-224832 (JP, A) JP-A-62-110973 (JP, A) JP-A-61-118136 (JP, A) JP-A-2001-511489 (JP, A) (58) Fields investigated ( Int.Cl. ⁷ , DB name) C08J 5/24

Claims (10)

(57) [Claims] 1. A prepreg obtained by subjecting a non-woven fabric made of aramid fibers to plasma treatment under normal pressure, impregnating a thermosetting resin, and then heating to B stage. 2. The plasma treatment according to claim 1, wherein as the reactive gas, a mixture of one or more of O ₂ , CO ₂ , N ₂ and NH ₃ is used. Prepreg. 3. The non-woven fabric, which has been plasma-treated under normal pressure, is dipped in an aqueous solution of a silane coupling agent, heated and dried, and then impregnated with a thermosetting resin. The listed prepreg. 4. A non-woven fabric that has been plasma-treated under normal pressure is dipped in an aqueous solution of an acrylic compound or a methacrylic compound, dried by heating, and then impregnated with a thermosetting resin. The prepreg described in 2. 5. The prepreg according to claim 1, wherein an epoxy resin is used as the thermosetting resin. 6. When impregnating a non-woven fabric with an epoxy resin,
6. A non-woven fabric is impregnated with a compound having an amino group as a curing agent in an amount such that the NH equivalent ratio to the epoxy equivalent of the epoxy resin with which the non-woven fabric is impregnated is 0.4 to 1.1. The listed prepreg. 7. The prepreg according to claim 1, wherein the amount of resin in the prepreg is 40 to 70% by weight based on the total amount of the prepreg. 8. The prepreg according to claim 1, wherein the aramid fiber non-woven fabric has a density of 0.5 to 0.8 g / cm ³ . 9. The prepreg according to claim 1, wherein the prepreg is produced by performing the steps from the plasma treatment to the impregnation with the thermosetting resin in a continuous step. 10. A laminate comprising the prepreg according to any one of claims 1 to 9 and a metal foil, which are stacked and heated and pressure-molded.