JPS61171738A - Production of laminate - Google Patents

Abstract

PURPOSE:To obtain a laminate having improved adhesiveness to cloth, improved mechanical strength and dimensional stability, by treating aromatic polyamide fiber cloths by plasma at low temperature, impregnating them with an epoxy adhesive, drying them to give prepreg, and subjecting plural sheets of the prepreg to contact bonding under heating. CONSTITUTION:Aromatic polyamide fiber cloths are treated by low-temperature plasma at 0.05-20Torr gas pressure, impregnated with an epoxy adhesive, dried, prepared plural sheets of prepreg are piled, and subjected to contact bonding under heating. The low-temperature plasma treatment is carried out by using a mixed gas of oxygen/nitrogen=95/5-5/95 (volume ratio). Preferably the cloths subjected to the low-temperature plasma treatment undergo surface treatmentn with a coupling agent containing an amino or epoxy group. B bisphenol A type epoxy resin, etcl, is used as the epoxy adhesive in an amount of 40-150wt% based on the cloth.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides cloth made of aromatic polyamide fibers and
This relates to a method for manufacturing laminates made of a laminate-based adhesive, and in particular aims to improve the adhesive strength between the crosses of laminates and provide laminates with excellent mechanical strength and dimensional stability. do.

(Prior technology) Aromatic polyamide fibers, represented by Kevlar (trade name) cloth, have excellent properties such as low density, high strength, high elasticity, heat resistance and flame resistance, and are suitable for use in heat-resistant laminates. Although it is very useful as a material, it has poor adhesion and adhesion with resin, and improvements are desired.

In order to improve the adhesion between aromatic polyamide fiber cloth and adhesive, various chemical treatments (chemical etching, primer treatment, etc.), corona treatment, etc. have been studied in the past, but aromatic polyamide fibers themselves cannot be chemically treated. Because it is a very stable substance, sufficient effects have not been obtained.

Epoxy adhesive is known as a resin with very good adhesive properties, but even when used, satisfactory adhesive strength has not been obtained with aromatic polyamide fiber cloth. Improvements are desired.

(Structure of the Invention) As a result of intensive study on this problem, the present inventors found that aromatic polyamide fibers were treated with low-temperature plasma at a gas pressure of 0.05 to 20 torr, then impregnated with an epoxy adhesive and dried. The inventors have discovered that a laminate with extremely excellent adhesion (adhesive) strength can be obtained by stacking a plurality of prepregs obtained and heat-pressing them, and have arrived at the present invention.

The present invention will be explained in detail below.

The method of manufacturing a novel laminate made of aromatic polyamide Ml fiber cloth and epoxy adhesive proposed by the present invention has the following configuration.

The first step of the present invention is to prepare aromatic polyamide fibers from 0.05 to
Treated with low temperature plasma of 20 Torr inorganic gas. As a method for performing low-temperature plasma treatment, the aromatic polyamide fiber is held in a low-temperature plasma generator capable of reducing pressure, and high-frequency power with a frequency of, for example, 10kllz'' and 100MHz is applied between the electrodes while passing inorganic gas under low pressure. It is done by

Note that as the discharge frequency band, in addition to the above-mentioned high frequency, low frequency, microwave, direct current, etc. can be used.

In the present invention, the low-temperature plasma generator is preferably of an internal electrode type, but may be of an external electrode type, or may be of a coil type, capacitively coupled, or inductively coupled. However, whatever method is used, it is necessary to prevent the surface of the treated object from being altered by the discharge heat.

The method of the present invention is preferably carried out using the internal electrode method as described above, but there are no particular restrictions on the shape of the electrodes, and the input side electrode and the ground side electrode may have the same shape or different shapes. They can be in various shapes such as a flat plate, a ring, a rod, a cylinder, etc. Furthermore, if the metal inner wall of the processing device is grounded as one electrode, t″m′″″+(7)t″Izv rG-ku
゛、tttE、"0"21. : generally copper, iron,
Aluminum or the like is used, but in order to maintain a stable discharge, it is preferable that the electrode be insulated and coated with glass, enamel, ceramic, etc. that has a withstand voltage of 10,000 V or more.In particular, the rod-shaped electrode coated with insulating material is: It is suitable for generating locally effective plasma.

Regarding the electric power applied between the electrodes, if it is too large, the object to be treated will decompose and deteriorate due to heat generation, so it is undesirable and needs to be controlled within a certain range. In the case of , because it has excellent heat resistance, the modification effect is more pronounced when the applied power is increased.

From this point of view, the power applied between the electrodes should be 5kW/m? It is preferable to set it as above.

Inorganic gases used in the present invention include sarium, neon, argon, nitrogen, nitrous oxide, nitrogen dioxide, oxygen,
Examples include air, carbon oxide, carbon dioxide, hydrogen, chlorine, hydrogen chloride, sulfur dioxide gas, and hydrogen sulfide, and these gases may be used alone or in combination. However, among these gases, particularly effective gases are oxygen and nitrogen, and a mixed gas of oxygen and nitrogen is even more effective in increasing the adhesiveness of aromatic polyamide fibers.

In this case, the mixing ratio of oxygen and nitrogen is oxygen/nitrogen = 9
515-5/95 preferably 10/90-60/40
(capacity ratio). The gas pressure within the plasma generator is between 0.05 and 20 torr, preferably
Preferably, it is carried out in a range of 0.1 to 10 torr. 0.05
At pressures below 5 Torr, the effect of improving adhesion proposed by the present invention is small, and at pressures above 20 Torr, it is difficult to maintain stable discharge and the effect of improving adhesion is small.

The aromatic polyamide fiber to be plasma treated may be treated in the form of a cord and then knitted, but in the case of the present invention, it is preferable to use commonly available cross-like materials such as plain weave, satin weave, and twill weave. .

Note that this cloth may be one in which aromatic polyamide fibers are used in combination with other fibers such as carbon fibers and glass fibers. The aromatic polyamide fiber cloth treated with low-temperature plasma is led to the second step of impregnating it with an epoxy adhesive, but it can be stabilized if it is pretreated with a coupling agent having amino groups or epoxy groups before that. This results in even better adhesion. Coupling agents used for this purpose include γ-aminopropyltriethoxysilane, γ-ethylenediaminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-
Examples include glycidoxypropylmethyldimethoxysilane. These fiber cloths are impregnated or coated as an aqueous solution or an organic solvent solution with a concentration of several percent or less, and then dried.

The aromatic polyamide fiber cloth that has been subjected to low-temperature plasma treatment is treated with a coupling agent if necessary as described above, and then led to the step of impregnating it with an epoxy adhesive. It is desirable to dry it sufficiently by heating and drying it at ~150°C or storing it in a drying room.

Typical epoxy adhesives include bisphenol A epoxy resin produced by the condensation reaction of bisphenol A and epichlorohydrin, flame-retardant brominated bisphenol A epoxy resin, and multifunctional phenol/novolak resin. In addition, 1,3-
Bis(N,N-diglycidylaminomethyl)cyclohexane.

N, N, N', 'N'-tetraglycidyl m
- Polyfunctional ethers such as xylene diamine, triglycidyl ciaslate, and diglycidylphenyl glycidyl ether are exemplified.

When using the above epoxy resin, curing catalysts include amines such as diethylenetriamine, triethylenetetramine, metaxylylene diamine, acid anhydrides such as phthalic anhydride and tetrahydrophthalic anhydride, tertiary amine salts,
Imidazoles, polyamide resins, boron trifluoride complex compounds, etc. are used. The type and amount of these curing catalysts are selected so that gelation does not proceed too much during solvent drying, which will be described later, and to maintain an appropriate gelation rate during press molding.

The mixture of epoxy resin and curing catalyst is usually
Previously, methyl ethyl ketone, dimethyl formamide,
Dissolved in methyl cellosolve etc. at a concentration of around 40-70%,
It is considered to be an impregnating liquid.

The amount of epoxy adhesive applied to the aromatic polyamide fiber cloth is 40 to 150% based on the weight of the fiber cloth.
By setting the amount preferably in the range of 60 to 120%, a vL layer body with extremely excellent interlayer adhesive strength can be obtained. 40%
Below that, the adhesive strength decreases rapidly.

This is different from conventional glass cloth and Kevlar cloth.
With a resin adhesion amount of 30-60%! This is a big difference compared to the case where the laminate was made, and is one proof of the uniqueness of the aromatic polyamide fiber cloth treated with low temperature plasma by the method proposed by the present invention.

The reason why the amount of epoxy adhesive impregnated in the present invention is required to be 40% or more, particularly 60% or more, is that the aromatic polyamide fiber cloth can be treated with low temperature plasma to improve wettability and affinity for the epoxy adhesive. death,
It is speculated that this is because the amount of adhesive that permeates into the fibers increases, and as a result, the amount of adhesive that contributes to the adhesion and adhesion between the cloth layers becomes insufficient in the conventional amount.

The prepreg obtained by impregnating with the above epoxy adhesive is dried to remove the solvent component, but this drying must be done under conditions that maintain the fluidity of the epoxy adhesive during pressure molding. It is said that Although the temperature and time of this drying vary depending on the activity of the adhesive resin and the solvent used, it is usually carried out at 110 to 160°C for 5 to 30 minutes.

A predetermined number of prepregs manufactured in this manner are stacked together and then transferred to the third step, which is a pressing step (pressure forming). As for the pressing conditions, it is important to make the distribution of the resin in the laminate uniform, and for this purpose, a method is used in which the resin is pressed and hardened while being made to flow. Appropriate press conditions include preheating at 130 to 160°C and 0 to 50 kg/ant, followed by curing at 160 to 200°C and 10 to 50 kg/cnT, and in order to sufficiently advance the curing, the pressing time is 30 It takes minutes to 3 hours.

The formed laminate is transferred to a fourth step, an after-cure step, in order to fully cure and remove unnecessary volatile components. The after-cure conditions are preferably set within a range from the press temperature to a temperature about 30° C. higher, and the temperature is maintained at the same temperature for 1 to 10 hours. Of course, it is also possible to omit the after-cure step by allowing sufficient pressing time.

The laminate obtained by the method of the present invention has excellent thermal conductivity, heat resistance, and dimensional stability, and also has improved interlayer adhesion between aromatic polyamide fiber cloths, so it has excellent bending strength, bending modulus, etc. It also has excellent mechanical properties. For this reason, it is useful as a structural material that requires heat resistance and one-dimensional stability.In particular, copper-clad laminates made of copper foils are required to be multilayered due to their heat resistance, dimensional stability, and thermal conductivity. The objective is to provide a material that can fully meet the needs of the industry as a multilayer print base material.

A detailed explanation will be given below with reference to examples.

Example 1 (Experiment Arashi 1 and Nα2) After a Kevlar cloth [Kanebo Co., Ltd. K-120 (SC-11)] was placed in the processing tank of a low-temperature plasma generator, the pressure was reduced using a vacuum pump. It was lowered to 0.01 Torr. In this state, a mixed gas of oxygen/nitrogen = 1/3 (volume ratio) was introduced, and the pressure was adjusted and maintained at 0.3 torr.
A power of 110 kHz and 25 klil was applied and the treatment was carried out for 1 minute.

The thus treated Kevlar cloth was impregnated with an epoxy adhesive having the following formulation, and then heated at 150° C. for 5 minutes to remove the solvent, thereby producing a prepreg.

Epicoat 1045-8-80 (manufactured by Shell Chemical Co., Ltd.) 150 parts by weight DICY (Toyo Ink Co., Ltd.) Imidazole 2E-4MZ (manufactured by Shikoku Kasei Co., Ltd.) 0.3 tt Methyl ethyl ketone 27. Methyl cellosolve
45〃Dimethylformamide 23
n The prepreg obtained in this way has an adhesive impregnation amount of 65%.
Met.

After stacking 10 sheets of this prepreg and setting 35μ electrolytic copper foil (manufactured by Nippon Mining Co., Ltd.) on the top and bottom,
Press molding was performed for 1 hour at f° C. and 30 kg/aJ.

After cooling, the molded product was taken out and abutment cured at 180°C for 1 hour, and then the interlayer adhesion between the cloths was measured (Experiment N (11). The interlayer adhesion strength of the formed laminate was measured (
Experiment Nu 2).

Example 2 (Experiment Nα3) After setting a Kevlar cloth [Kanebo Co., Ltd. K-120 (SC-11)] into the processing tank of a low-temperature plasma generator, the pressure was reduced using a vacuum pump to bring the pressure to 0. I lowered it to Oltor. In this state, oxygen gas was introduced, the pressure was adjusted and maintained at 0.3 torr, and then a voltage of 110 kllz and 25 kW was applied and the treatment was carried out for 1 minute. The interlayer adhesive strength of the Kevlar cloth treated in this manner was measured in the same manner as in Example 1 (Experiment Nα3).

Example 3 (Experiment Nn 4 and Experiment Ha 5) After setting Kevlar cloth [Kanebo Co., Ltd. K-120 (SC-11)] into the processing tank of the low-temperature plasma generator,
The pressure was reduced to 0.01 Torr using a vacuum pump. In this state, a mixed gas of oxygen/nitrogen = 3/1 (volume ratio) was introduced, and after adjusting and maintaining the pressure at 0.6 Torr,
A voltage of 10k)lz and 20k11 was applied and the treatment was carried out for 30 seconds. After impregnating the Kevlar cloth treated in this way with an epoxy adhesive having the following composition,
A prepreg was prepared by heating at 0° C. for 5 minutes and removing the solvent.

Epicoat 1045-B-80 (manufactured by Shell Chemical Co., Ltd.) 130 parts by weight Epicoat 154 (manufactured by Shell Chemical Co., Ltd.) 20° DICY (manufactured by Toyo Ink Co., Ltd.) 5 Imidazole 2E-4MZ (manufactured by Shikoku Kasei Co., Ltd.) 0.2 #Methyl ethyl ketone 40 〃Methyl cellosolve
40 II dimethylformamide
30 The prepreg obtained in this way has an adhesive impregnation amount of 8
It was 0%.

After stacking 10 sheets of this prepreg and setting 35μ rolled copper foil (manufactured by Nihon Mining Co., Ltd.) on the top and bottom, the sheets were heated at 160℃ for 30 minutes.
Press molding was performed for 1 hour at 0 kg/cd.

After cooling, the molded product was taken out and heated at 180°C for 1 hour.
- After curing, the interlayer adhesive force between the cloths was measured (Experiment Na4). Note that the interlayer adhesion strength of a similarly molded laminate was measured using untreated Kevlar cloth (experiment Na 5 ).

The above experimental results are summarized in Table 1.

Table 1 Method for measuring interlayer adhesion strength Cut a 1cm x 12cm sample piece from the center of the laminate, peel off the upper and lower copper foils, and measure the peel strength between the crosses at 18cm.
Measurement was performed by peeling at 0°. Note that the tensile speed was 5 m/min.

Measurement of adhesive impregnation amount PL: Weight of prepreg after drying at 300°C for 30 minutes P2: Weight of Kevlar cloth

Claims (1)

[Claims] 1. Aromatic polyamide fiber cloth is heated to a gas pressure of 0.05 to
A method for manufacturing a laminate, which comprises stacking a plurality of prepregs obtained by treating with low-temperature plasma at 20 torr, impregnating with an epoxy adhesive and drying the prepregs, and then heat-pressing the prepregs. 2. The above low temperature plasma treatment is performed with oxygen/nitrogen = 95/5 to 5.
2. The manufacturing method according to claim 1, wherein the manufacturing method is carried out using a mixed gas of /95 (volume ratio). 3. The aromatic polyamide fiber cloth subjected to the low-temperature plasma treatment is surface-treated with a coupling agent having an amino group or an epoxy group, and then impregnated with an epoxy adhesive. manufacturing method.