JPH0344574B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a continuous manufacturing method for laminated boards used for printed wiring boards and the like. [Background technology] In manufacturing laminates used for printed wiring boards, etc., prepreg cut into squares of predetermined dimensions and metal foil are stacked in multiple stages between heating plates and heated at high temperature and pressure. A multi-stage press method in which laminates are heated and pressed for a long period of time has been commonly used in the past, and it can be said that this multi-stage press method is currently the main method for manufacturing laminates. However, this method has the problem of low productivity because it is molded in batches, and because it is pressurized at high pressure, large distortions remain in the formed laminate, resulting in dimensional stability. In addition to the problem that the high pressure causes a large amount of resin to flow out from the periphery of the laminate, the thickness of the laminate becomes thinner at the periphery than the center, resulting in poor laminate thickness accuracy. There is. Furthermore, in this multi-stage pressing method, the laminate is formed by laminating prepreg cut into squares and metal foil, so each of the four edges of the laminate is cut and removed to finish the product. However, there is also the problem that the loss of metal foil increases due to the cutting and removal of the four circumferential edges. For this purpose, by stacking a long prepreg and metal foil between a pair of metal endless belts and continuously feeding them, the prepreg and metal foil can be stacked between the double belts formed by the pair of endless belts. Consideration has been given to adopting the so-called double belt method, in which laminated plates are continuously manufactured by heating and pressing metal foil. According to this method, laminates can be manufactured continuously with good productivity rather than in batches, and pressurization can be performed at a relatively low pressure, improving the dimensional stability and thickness accuracy of the laminate. Furthermore, since the laminate only needs to be cut and removed from both edges in the width direction, loss of metal foil can also be reduced. Here, according to this double belt method, pressurization is performed at a relatively low pressure as described above, so as the resin for preparing the prepreg, an epoxy resin that does not generate gas components such as condensed water during the curing reaction is used. It is said that it is preferable to use
Then, the prepreg prepared by impregnating the base material with the epoxy resin composition is passed through a double belt for molding, and the impregnated epoxy resin is cured during the short time that the prepreg is passed through the double belt. Therefore, if you do not use an epoxy resin composition that cures 10 to 50 times faster than that used in the conventional multi-stage press method, curing will be insufficient and the overall quality will deteriorate. Therefore, reliability as a wiring board cannot be obtained. Therefore, in order to speed up the curing speed of the epoxy resin, it is being considered to prepare an epoxy resin composition by increasing the amount of curing agent and curing accelerator, and to use an epoxy resin composition that increases the curing speed of the epoxy resin. However, if the curing speed of the epoxy resin is increased by increasing the amount of curing agent or curing accelerator, the cured resin becomes hard and brittle, which causes a decline in properties such as drill abrasion resistance of the laminate. . As described above, it is not practical to use epoxy resins for continuous molding of laminates using the double belt method that increase the curing speed by increasing the amount of curing agent or curing accelerator.
This was one of the reasons why it was difficult to put the continuous forming method of laminates into practical use. [Objective of the Invention] The present invention has been made in view of the above points, and provides a method for manufacturing an epoxy resin laminate with good productivity that does not require the use of large amounts of curing agents or curing accelerators and has excellent properties. The first purpose is to provide a method for continuous production of laminates that can produce laminates, and the second purpose is to prevent the generation of vertical wrinkles in the metal foil on the surface of laminates. The third objective is to improve the dimensional stability of the material. [Disclosure of the Invention] Accordingly, in the present invention, α-
An epoxy resin composition is prepared using an epoxy resin containing a diol group and a hydrolyzable chlorine group as a main component, and a base material is impregnated with this epoxy resin composition to create a long prepreg. A continuous manufacturing method for a laminate, which comprises heating and pressurizing one or more sheets of prepreg and a long metal foil while continuously feeding them while overlapping them so that the metal foil becomes the outermost layer. The first invention is characterized in that the total amount of 1/2 of the hydroxyl group of the α-diol group and the hydrolyzable chlorine group is 0.01 of the epoxy resin.
An epoxy resin composition is prepared using an epoxy resin containing an α-diol group and a hydrolyzable chlorine group as a main component so that the amount is in the range of ~0.14% by weight, and a base material is impregnated with this epoxy resin composition. One or more sheets of long prepreg and a long sheet of metal foil are stacked on top of each other so that the metal foil becomes the outermost layer and are continuously fed while heating and pressurizing them. Before heating and pressing, heat the metal foil to 50 to 250℃ higher than the prepreg.
The second invention is a method for continuously manufacturing a laminate, which is characterized by heating to a high temperature, and furthermore, the total amount of 1/2 of the hydroxyl group of the α-diol group and the hydrolyzable chlorine group is epoxy. An epoxy resin composition is prepared using an epoxy resin containing an α-diol group and a hydrolyzable chlorine group as a main component so that the amount is in the range of 0.01 to 0.14% by weight of the resin, and an epoxy resin composition is prepared using the epoxy resin composition as a base material. A long prepreg is created by impregnation, and one or more sheets of long prepreg and a long metal foil are overlapped with each other so that the metal foil becomes the outermost layer and are continuously fed while being heated. The third invention is a method for continuous production of a laminate, which is characterized in that the laminate obtained by pressing and then heating and pressing is heat-treated at a temperature of 130°C to 200°C under no pressure, and the following is described below. The present invention will be explained in detail. First, the first invention will be explained in detail. Examples of the epoxy resin used in the present invention include bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, cresol novolak type epoxy resin, and phenol novolak type epoxy resin. mainly targets epoxy resins that use epichlorohydrin as one of the raw materials. In the course of conducting research to accelerate the curing speed of epoxy resins, the present inventors discovered that it is inevitable that epoxy resins contain hydrolyzable chlorine groups and α-diol groups in their molecules. I got it. In other words, the hydrolyzable chlorine group is formed by chlorine introduced into the system for synthesizing the epoxy resin using, for example, epichlorohydrin, by ring-opening and bonding of the epoxy groups in the epoxy resin. exists in Further, the α-diol group exists, for example, in the following form when water causes the epoxy group in the epoxy resin to ring-open and react. The present inventors have discovered that the hydrolyzable chlorine groups and α-diol groups present in such epoxy resins have a large effect on the curing speed of epoxy resins, and have completed the present invention. be. In other words, the presence of hydrolyzable chlorine groups and α-diol groups in the epoxy resin means that the number of epoxy groups that contribute to the curing reaction (crosslinking reaction) of the epoxy resin decreases. Hydrolyzable chlorine groups and α-
It is thought that as the content of diol groups increases, the curing rate of the epoxy resin, especially the initial curing rate, decreases. Moreover, as the content of hydrolyzable chlorine groups and α-diol groups present in the epoxy resin increases, the crosslinking density due to the epoxy groups decreases, resulting in a decrease in the properties of the epoxy resin after curing. In particular, the hydrolyzable chlorine group reacts with a curing accelerator such as imidazole compounded in the epoxy resin composition as shown in the following formula, This advances the epoxy ring-closing reaction and prevents the epoxy ring-opening polymerization, resulting in a delay in the curing speed of the epoxy resin, and furthermore, the curing accelerator is consumed by liberated Cl ^- , resulting in curing. The curing accelerating effect of the accelerator will be reduced. When an epoxy resin contains a large amount of hydrolyzable chlorine groups or α-diol groups, the curing speed slows down, and for this reason, conventional methods have been known to increase the amount of curing agent and curing accelerator. It became necessary to obtain a curing rate that could cope with continuous molding using the double belt method, but in the present invention, the content of hydrolyzable chlorine groups and α-diol groups was kept within a certain range. By using a limited amount of epoxy resin, the epoxy resin composition can be quickly cured and used without the need to increase the amount of curing agent or curing accelerator.
That is, in the present invention, the main component is an epoxy resin in which the content of hydrolyzable chlorine groups and α-diol groups is 0.01% by weight≦hydrolysable chlorine groups + 1/2 (hydroxyl group of α-diol group)≦0.14% by weight. An epoxy resin composition is prepared and used. In other words, hydration is carried out so that the total weight ratio of the hydrolyzable chlorine group (Cl) to one of the hydroxyl groups (OH) contained in the α-diol group in the solid content of the epoxy resin is 0.14% by weight or less. It uses an epoxy resin with a limited content of degradable chlorine groups and α-diol groups.
- By limiting the total amount of diol groups to this value, the curing speed of the epoxy resin can be accelerated without the need to increase the amount of curing agent or curing accelerator, making it suitable for continuous production of laminates using the endless belt method. Therefore, it is possible to prepare an epoxy resin composition. Further, in the present invention, the lower limit of the total weight ratio of the hydrolyzable chlorine group and one hydroxyl group of a pair of hydroxyl groups contained in the α-diol group in the solid content of the epoxy resin is defined as 0.01% by weight.
In order to reduce the hydrolyzable chlorine groups and α-diol groups contained in the epoxy resin, the hydrolyzable chlorine groups must be removed by dehydrochloric acid treatment, or α-diol groups can be removed by dehydrochloric acid treatment.
- It is necessary to remove the hydroxyl group of the diol group by dehydration, but when the epoxy resin is treated in this way, the viscosity of the epoxy resin increases, making it difficult to impregnate the base material, making it difficult to put it into practical use. This is because it becomes impossible to do so. Therefore, the content of hydrolyzable chlorine groups and α-diol groups in the epoxy resin used in the present invention is 0.01% by weight≦hydrolysable chlorine groups + 1/2 (hydroxyl group of α-diol group)≦0.14% by weight %, and in particular, the content of hydrolyzable chlorine groups and α-diol groups is 0.02% by weight≦hydrolyzable chlorine groups + 1/2 (hydroxyl group of α-diol group)≦0.09 It is preferable to use epoxy resin in weight percent. In addition, the hydrolyzable chlorine group contained in the epoxy resin and α-
If diol groups and diol groups were to be regulated separately, the content of hydrolyzable chlorine groups contained in epoxy resins would be
0.01-0.07% by weight, preferably 0.01-0.04% by weight
The α-diol group contained in the epoxy resin has a hydroxyl group content of 0.01 to 0.13% by weight,
Preferably, each content is regulated within the range of 0.01 to 0.10% by weight. Furthermore, it is preferable to use an epoxy resin with an epoxy equivalent in the range of 180 to 700 g/eq, and the content of bromine (Br) in the range of 0 to 50% by weight to provide flame retardance.
can also be included. Thus, a liquid epoxy resin composition such as a varnish-like composition is prepared by containing the above-mentioned epoxy resin as a main component and further adding a curing agent and a curing accelerator. In addition, reactive diluents, non-reactive diluents, fillers, etc. can also be blended within a range that does not impede the object of the present invention. Here, as a curing agent, any one commonly used for epoxy resins such as aliphatic amine type, aromatic amine type, acid anhydride, etc. can be used, and as a curing accelerator, such as imidazoles etc. commonly used for epoxy resins can be used. Any one can be used.
Furthermore, as reactive diluents, novolak type epoxy resin, cresol novolak type epoxy resin,
Furthermore, brominated versions of these can be used, and as non-reactive diluents, solvents such as methyl ethyl ketone, dimethyl formamide, dimethyl acetamide, and acetone can be used. The amount of the curing agent and curing accelerator varies depending on the type and is not particularly limited, but it is 2 to 4 parts by weight of the curing agent and 0.1 part of the curing accelerator per 100 parts by weight of the epoxy resin. It is generally set at about 0.5 parts by weight. If the curing agent or curing accelerator is added in an amount exceeding this range, the resin after curing will become hard and brittle, resulting in deterioration of the properties of the laminate. A prepreg can be prepared by impregnating a base material with the epoxy resin composition obtained as described above and heating and drying it. As the base material, glass cloth such as glass woven fabric, glass nonwoven fabric, glass matte, etc. is used. However, it is also possible to use other inorganic fibers such as asbestos, organic synthetic fibers such as polyester and polyamide, woven or non-woven fabrics made of natural fibers such as cotton, mat, or paper. When using glass cloth as the base material,
Its thickness is preferably 0.1 mm to 0.3 mm. When preparing a prepreg by impregnating a base material with an epoxy resin composition, it is necessary to ensure that the portion of the base material that is not impregnated with the epoxy resin composition is less than 0.3% of the surface area of the base material, and that the number of bubbles contained is It is desirable that the number of particles be 500 or less per square inch. If the base material is not sufficiently impregnated with the epoxy resin composition, and the unimpregnated portion of the base material increases, and the number of air bubbles increases, the molded laminate will suffer from scratches, resulting in poor appearance. Not only will it become;
In some cases, the physical properties of the laminate deteriorate, resulting in significantly inferior heat resistance and electrical properties. In particular, in the double belt method, molding is performed at relatively low pressure, so the pressure to penetrate the epoxy resin into the unimpregnated parts of the base material and the pressure to expel air bubbles from the base material during molding is insufficient. Moreover, since the double belt method uses an epoxy resin with a fast curing speed, the resin hardens instantly, and the resin cannot be sufficiently poured into the bubbles, making it difficult to impregnate the base material with the epoxy resin. It is necessary to carefully prepare the prepreg so that the unimpregnated portion of the epoxy resin composition is less than 0.3% of the surface area of the base material and contains no more than 500 bubbles per square inch. It will become. In order to sufficiently impregnate the base material with the epoxy resin composition, impregnation is carried out by the so-called vacuum impregnation method, in which the base material is impregnated with the epoxy resin composition under reduced pressure conditions using a vacuum chamber. is desirable. For example, FIG. 1 shows an apparatus for producing prepreg 2, in which a pair of rolls 6 and 7 are attached to the inlet and outlet of a vacuum chamber 5 connected to a vacuum device such as a vacuum pump. The base material 1 of the length is passed through a roll 6 and pressurized, and then introduced into a vacuum chamber 5. Inside the vacuum chamber 5
The pressure is reduced to about 50 Torr or less, and the air contained in the base material 1 is sucked out by the depressurization action within the vacuum chamber 5, and the inside of the base material 1 is also brought into a reduced pressure state. Then, when the base material 1 is taken out from the vacuum chamber 5 and passed through the roll 7, the epoxy resin composition 4 prepared in the mixing device 8 is mixed.
is supplied to impregnate the base material 1 with the epoxy resin composition 4, but since the inside of the base material 1 is in a reduced pressure state, the epoxy resin composition 4 penetrates into the base material 1 well. , the unimpregnated portion of the epoxy resin composition can be reduced, and the number of bubbles included can also be reduced. After the base material 1 is impregnated with the epoxy resin composition by the vacuum impregnation method, the base material 1 is passed through an impregnation tank 9 to further impregnate the epoxy resin composition 4, and the base material 1 is placed on a squeeze roll 10. Through the base material 1
The amount of epoxy resin composition 4 impregnated into the sample is adjusted.
The amount of impregnation is not particularly limited, but it is common that the resin content in the dry resin-impregnated base material is about 35 to 60% by weight. After the base material 1 is impregnated with the epoxy resin composition as described above, the base material 1 is passed through the dryer 11 and heated with radiant heat to evaporate the solvent in the epoxy resin composition and cause the reaction of the epoxy resin. The prepreg 2 is partially progressed to a B stage state and is in a non-sticky state at room temperature. The long prepreg 2 thus obtained is rolled up and stored. It is best to store it in an air-conditioned room with a temperature below 25°C and a RH below 40%. Using the elongated prepreg 2 produced as described above, a laminate can be manufactured using, for example, a forming apparatus as shown in FIG. 2. That is, first of all,
One or a plurality of prepregs 2 are continuously fed and stacked while being unrolled, and a long metal foil 3 is further stacked on the outer surface of the outermost layer of the prepregs 2. When manufacturing a laminate with metal foil on both sides, the metal foil 3 is used to overlap both outermost layers of the prepreg 2, but when manufacturing a laminate with metal foil on one side, the metal foil 3 is used on the prepreg 2. It will be used by overlapping only the outermost layer on one side. Further, as the metal foil 3, a material capable of forming a circuit on a printed wiring board, such as copper foil or aluminum foil, is used. The prepreg 2 and the metal foil 3 are stacked together as a pair of metal endless belts 12, 12.
It is continuously fed into a double belt 13 formed by. Each endless belt 12, 12 of the double belt 13 is in a heated state, and the prepreg 2 is heated and pressurized by the double belt 13. The heating and pressurizing conditions are not particularly limited, but are generally set at 170-200°C and 40 kg/cm ² or less, and the time required for passing through the double belt 13 is 1.5-30°C. It is common to set the time to about a minute. Further, it is desirable to set the heating temperature of the double belt 13 so that the heating rate of the prepreg 12 is 100° C./min or more. By continuously feeding the prepreg 2 through the double belt 13 and heating and pressurizing it, the epoxy resin in the prepreg 2 is melted and a curing reaction progresses. It is possible to continuously form a laminate A in which these are laminated and integrated. After the laminate A undergoes an appearance inspection with the inspection device 15, it is cut into a predetermined size by the cutting device 16, and the cut laminate A is loaded on a table 17 and transported to the next process. Next, the second invention of the present invention will be explained. The prepreg is prepared in the same manner as in the first invention, but in the second invention, when the prepreg and the metal foil are overlapped and continuously heated and pressed using a double belt, the metal foil is The prepreg is preheated to a temperature 50 to 250°C higher than the prepreg, and in this state, the prepreg and metal foil are stacked and fed into the double belt, and the rest is done using the double belt in the same manner as in the first invention above. A laminate is obtained by continuous heating and pressure molding. When prepreg and metal foil are stacked at almost the same temperature and fed into a double belt for heating and pressure forming, vertical wrinkles occur in the metal foil on the surface of the laminate, parallel to its longitudinal direction (feeding direction). There are things to do. The reason for this is not clear, but when prepreg and metal foil are stacked and fed into the double belt, the metal foil, which has a high thermal conductivity and high coefficient of thermal expansion, is quickly heated and expands greatly. Therefore, the thermal expansion behavior of the metal foil and the prepreg differs greatly, and as a result, it is thought that vertical wrinkles will occur in the metal foil in the laminate. Therefore, in the second invention, the metal foil is heated in advance and thermally expanded before being introduced into the double belt.
This was done to prevent a large difference in thermal expansion behavior between the metal foil and the prepreg, and to prevent the occurrence of vertical wrinkles in the metal foil on the surface of the laminate. The heating temperature of metal foil is 50° higher than that of prepreg.
If the heating temperature of the metal foil is not higher than 250℃, the prevention of vertical wrinkles will not be sufficient. This is not practical as there is a risk of discoloration and deterioration of the copper foil (copper foil).
It should be noted that the second invention is particularly effective when using a metal foil with a thickness of 5 to 35 microns, since there is less risk of vertical wrinkles occurring when the metal foil is thick. Next, the third invention will be explained. The laminate is formed in the same manner as in the first invention or the second invention, but in the third invention, after cutting the laminate to a predetermined size, the cut laminate is molded under no pressure for 130 minutes.
Heating at a temperature of ~200℃, preferably 155-175℃,
It is designed to be heat treated. The heating time is not particularly limited, but is preferably about 10 to 60 minutes. When manufacturing a laminate using the double belt method, the forming pressure is relatively low, so no significant distortion remains in the laminate, but some distortion remains in the laminate. Therefore, in the third invention, the residual strain of the laminate is removed by heat-treating the laminate and after-curing the laminate, thereby further improving the dimensional stability characteristics. If the heat treatment temperature is less than 130℃, the effect of removing residual strain cannot be sufficiently obtained and the effect of improving dimensional stability is insufficient.If the heat treatment temperature exceeds 200℃, metal foil (especially This is not practical as there is a risk of discoloration and deterioration of the copper foil (copper foil). Furthermore, if the heat treatment is performed under pressure conditions, there is a risk that the laminate may warp or twist, so the heat treatment must be performed under no pressure conditions. Next, the present invention will be further explained with reference to Examples. (First invention) Examples 1 to 12 As an epoxy resin, hydrolyzable chlorine groups and α-
The hydroxyl content of the diol group, the epoxy equivalent, and the bromine content shown in Table 1 were used, and this was dissolved in methyl ethyl ketone so that the solid content was 80% by weight. Table 1 shows the viscosity of the epoxy resin at this time. In Table 1, the brominated bisphenol A type epoxy resin is YDB500 manufactured by Toto Kasei Co., Ltd., and the cresol novolak type epoxy resin is YDCN220 manufactured by Toto Kasei Co., Ltd.
R350 manufactured by Mitsui Petrochemical Co., Ltd. was used as the bisphenol A type epoxy resin, and R350 manufactured by Dainippon Ink Co., Ltd. was used as the highly brominated bisphenol A type epoxy resin.
Epc1125 was used, respectively. Further, 3PHR of dicyandiamide as a curing agent and 2-ethyl-4-methylimidazole as a curing accelerator were added in the amounts shown in Table 1 to prepare an epoxy resin composition as an epoxy resin varnish. Table 1 shows the gelation time of this epoxy resin varnish. Next, a long glass woven fabric with the thickness shown in Table 2 was used as the base material, and the first
The epoxy resin varnish was impregnated by a vacuum impregnation method in which a glass woven fabric was passed through the vacuum chamber of the apparatus shown in the figure.
By heating and drying this at 155° C. for 3 minutes, a long prepreg with the resin content shown in Table 2 was obtained. Table 1 shows the proportion of the surface area of the unimpregnated portion of the epoxy resin in this prepreg, the number of bubbles, and the gelation time. The long prepreg created as described above is
Copper foils with a thickness of 35 μm were stacked on the outermost layer on both sides of the prepreg in the number shown in the table, and the sheets were continuously fed into the double belt shown in Figure 2 to perform heating and pressure forming using the double belt method. . The molding conditions using double belt are molding temperature 180℃,
The molding pressure was set at 15 kg/cm ² and the molding time was set at 2 minutes. At this time, the temperature of the prepreg was raised to 180°C approximately 30 seconds after it was introduced into the double belt. By continuously forming the double-belt method in this way, a laminate with the thickness shown in Table 2 is created, and then the long laminate is cut to create a double-sided copper-clad laminate. Finished as a board. Regarding the double-sided copper-clad laminate obtained in this way, "dimensional stability (variation; σ _o-1 )", "plate thickness accuracy (variation; σ _o-1 )", "presence of scratching", "solder heat resistance" properties,” “moisture absorption and heat resistance,” and “insulation resistance (D-2/
100)'', ``drill abrasion'', ``electrolytic corrosion'', and ``amount of plating liquid permeated'', respectively. The results are shown in Table 3. Here, ``dimensional stability'' is measured by measuring the variation in the dimensional change rate in the lateral direction (width direction of the base material) of the laminate after the surface copper foil is removed by etching. I did it. To measure "moisture absorption and heat resistance," the laminate is placed in an autoclave at 120°C to absorb moisture for 90 minutes, then immersed in a solder bath at 260°C, and the presence or absence of blistering is checked after 20 seconds. I did it. If no blistering occurred in this test, the sample was further allowed to absorb moisture for a period of time shown in Table 3, and the presence or absence of blistering was similarly confirmed. The measurement of "drill abrasion" was performed using a sample of stacked laminate plates with a total thickness of 4.8 mm, and the wear of the drill tip when drilling 6000 times with the drill tip. This was done by measuring the dimensions using micrographs. To measure electrolytic corrosion, a double-sided through-hole wiring board with a circuit spacing of 150μ was created from a double-sided copper-clad laminate, and a voltage of 15 V DC was applied to it in an accelerated humidified atmosphere at 60°C and 95% RH. The resistance value between the circuits is 1
This was done by measuring the time it took for the resistance to reach ×10 ⁶ Ω. Measuring the amount of “metsuki liquid seepage” is as follows:
A plating treatment was applied to the sample after the 4000th drilling in the drill abrasion test, and the length of penetration of the plating liquid along the fibers of the base material was measured. Other measurements were performed based on JIS standards.

【table】

【table】

【table】

【table】

【table】

[Table] Comparative Examples 1 to 9 Epoxy resins containing hydrolyzable chlorine groups or α-
Using diol groups whose hydroxyl group content, epoxy equivalent, and bromine content are shown in Table 4, they were dissolved in methyl ethyl ketone in the same manner as in "Examples 1 to 11" above, and further added as a curing agent. An epoxy resin composition was prepared as an epoxy resin varnish by blending 3 PHR of dicyandiamide and 2-ethyl-4-methylimidazole as a curing accelerator in the amounts shown in Table 4. Table 4 shows the gelation time of this epoxy resin varnish. Next, using a glass woven fabric having the thickness shown in Table 5 as a base material, for Comparative Examples 1 to 3 and Comparative Examples 6 to 9, the same vacuum impregnation method as in "Examples 1 to 11" was carried out.
For Comparative Examples 4 and 5, the resin contest prepregs shown in Table 5 were obtained by impregnating each with epoxy resin varnish under normal pressure and heating and drying this under the conditions shown in Table 5. Table 5 shows the proportion of the surface area of the unimpregnated portion of the epoxy resin in this prepreg, the number of bubbles, and the gelation time. The prepregs prepared as described above were stacked in the number shown in Table 5, and copper foils with a thickness of 35 μm were stacked on the outermost layer on both sides of the prepreg, respectively, and Comparative Examples 1 to 4
And for Comparative Examples 7 and 8, see the above “Examples 1-
Continuous molding using the same double belt method as ``11'',
For Comparative Examples 5, 6, and 9, double-sided copper-clad laminates having the thickness shown in Table 5 were obtained by molding using a multistage press method and applying heat and pressure. The molding conditions are shown in Table 5. Regarding the laminate thus obtained, various characteristics were measured in the same manner as in "Examples 1 to 11", and the results were reported in the sixth
Shown in the table.

【table】

【table】

[Table] From the comparison of the gelation time of the epoxy resin varnishes in Tables 1 and 4, it is found that Comparative Examples 2 to 9, which have a high content of hydrolyzable chlorine groups and α-diol groups, have a hardening accelerator. It has been confirmed that the curing speed is slow unless a large amount of epoxy resin varnish is blended. Especially in Comparative Examples 3, 5, and 6, where the gelation time of the epoxy resin varnish is extremely long, it is necessary to make sure that the heating time is not sufficient when preparing the prepreg. However, as shown in Table 5, it is confirmed that it is difficult to shorten the gelation time in prepreg. In addition, hydrolyzable chlorine groups and α-
Comparative Example 1 with extremely low diol group content
It is confirmed that the viscosity becomes very high and the number of unimpregnated portions and bubbles in the prepreg increases. From a comparison between Table 3 and Table 6, it is confirmed that each example can satisfy various characteristics. (Second invention) Examples 13 to 17 Epoxy resin varnishes were prepared using the same epoxy resin as in Example 5, and prepregs were also created in the same manner as in Example 5. Then, when this prepreg and copper foil are stacked and heated and pressure-molded using the double belt method in the same manner as in Example 5, the copper foil is heated in advance and the temperature difference shown in Table 7 is higher than that of the prepreg at room temperature. The temperature was kept high, and in this state the prepreg and copper foil were layered and sent to a double belt. Table 7 shows the thickness of the copper foil used. Regarding the double-sided copper-clad laminate thus formed, the number of vertical wrinkles per 1 m ² occurring in the copper foil on the surface was measured, and the state of discoloration of the copper foil was observed. The results are shown in Table 7. Comparative Examples 10 and 11 Except that the copper foil was heated to a higher temperature than the prepreg at room temperature with the temperature difference shown in Table 7,
Double-sided copper-clad laminates were obtained in the same manner as in "Examples 13 to 17." Regarding the double-sided copper-clad laminate thus obtained, the number of vertical wrinkles occurring in the copper foil on the surface was measured, and the state of discoloration of the copper foil was observed. The results are shown in Table 7. (Third Invention) Examples 18 to 20 A long laminate was produced using the double belt method in the same manner as in Example 5, and after cutting this laminate, the cut laminate was placed in a non-pressure state. Heat treatment was carried out by heating at the temperature shown in Table 8 for 30 minutes.
The dimensional change rate and warp twist of the double-sided copper-clad laminate thus obtained were measured (E-1.0/
170), and the presence or absence of discoloration of the copper foil was also observed. The dimensional change rate and warping/twisting were measured on the laminate after etching and removing the copper foil on the surface, and the average value ( ), variation (σ _o-1 ), and maximum value (max) were measured. The results are shown in Table 8. Comparative Examples 12-15 Double-sided copper-clad laminates were obtained in the same manner as in Examples 18-20, except that the heat treatment was performed at the temperatures shown in Table 8. At this time, Comparative Examples 12 and 13 were heat treated under no pressure, but Comparative Examples 14 and 15
The heat treatment was carried out with the laminate under pressure of 30 kg/cm ² . The dimensional change rate, warping/twisting, and discoloration of the copper foil of the double-sided copper-clad laminate thus obtained were measured, and the results are shown in Table 8. Comparative Example 16 A double-sided copper-clad laminate was produced using the multi-stage pressing method in the same manner as Comparative Example 5, and was heated at 165°C for 30 minutes under no-pressure conditions.
Heat treatment was performed by heating for a minute. The dimensional change rate, warping/twisting, and discoloration of the copper foil of the double-sided copper-clad laminate thus obtained were measured, and the results are shown in Table 8.

【table】

[Table] The results in Table 7 show that in each example in which the copper foil was preheated to a higher temperature than the prepreg in the temperature range of 50 to 250°C, vertical wrinkles were observed in the copper foil on the surface of the laminate. However, if the heating temperature of the copper foil is insufficient, vertical wrinkles will occur as in Comparative Example 10, and if the heating temperature of the copper foil is too high, vertical wrinkles will occur as in Comparative Example 11. It is confirmed that discoloration occurs on the copper foil as shown in the figure. Furthermore, as shown in Table 8, in each example in which the heat treatment was carried out within the temperature range of 130 to 200°C, the dimensional change rate could be reduced and the copper foil would not discolor. It is confirmed that in Comparative Example 12, where the heat treatment temperature is too low, the average value of the dimensional change rate () is large, and in Comparative Example 13, where the heat treatment temperature is too high, discoloration occurs in the copper foil. . Furthermore, it was confirmed that warping and twisting was small in each of the examples in which heat treatment was performed under no pressure, but large warping and twisting occurred in Comparative Examples 14 and 15, in which heat treatment was performed under pressure. be done. Furthermore, as seen in Comparative Example 16, it is confirmed that the laminate formed by the multi-stage pressing method has almost no effect of improving dimensional stability even if heat treatment is performed. [Effect of the invention] As described above, in the present invention, the total amount of the hydrolyzable chlorine group and 1/2 amount of the hydroxyl group of the α-diol group is in the range of 0.01 to 0.14% by weight of the epoxy resin. First, an epoxy resin composition was prepared using an epoxy resin containing a hydrolyzable chlorine group and an α-diol group as a main component, and a long prepreg was prepared by impregnating a base material with this epoxy resin composition. Since the prepreg and the long metal foil are overlapped and continuously fed while being heated and pressurized, the epoxy resin hardens due to the presence of a large number of hydrolyzable chlorine groups and α-diol groups. It is possible to reduce speed delays and to produce laminates with excellent various properties using a continuous molding method without the need to incorporate large amounts of curing accelerators. In addition, the second invention of the present invention is that when heating and pressing the prepreg and the metal foil in a stacked manner, the metal foil is heated to a temperature 50° higher than the prepreg before the heating and pressing.
I decided to heat it to a temperature ~250℃ higher, so
The metal foil is thermally expanded in advance to prevent a large difference in thermal expansion behavior between the prepreg and the metal foil during heating and pressurization, and to prevent vertical wrinkles from occurring in the metal foil on the surface of the laminate. It is something that can be prevented. Furthermore, the third aspect of the present invention is to cut the laminate obtained by heating and pressurizing it and then cutting it under no pressure.
Since the heat treatment is carried out at a temperature of 120 to 130℃, there is no risk of warping or twisting because it is under pressureless conditions, and this heat treatment further improves the dimensional stability of the laminate by removing residual strain in the laminate. It is something that can be done.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a prepreg manufacturing apparatus employing a vacuum impregnation method, and FIG. 2 is a schematic diagram of a laminate forming apparatus employing a double belt. 1 is a base material, 2 is a prepreg, 3 is a metal foil, and 4 is an epoxy resin composition.

Claims (1)

[Claims] 1. The total amount of 1/2 of the hydroxyl group of the α-diol group and the hydrolyzable chlorine group is 0.01 to 0.14 of the epoxy resin.
An epoxy resin composition is prepared using an epoxy resin containing an α-diol group and a hydrolyzable chlorine group as a main component so that the epoxy resin composition is within the range of % by weight. The method involves creating a length of prepreg, and heating and pressurizing one or more long prepregs and a long metal foil while continuously feeding them while overlapping each other so that the metal foil becomes the outermost layer. Continuous manufacturing method for laminates. 2. The epoxy resin is made of α-
2. The continuous production method of a laminate according to claim 1, wherein the laminate contains a diol group and a hydrolyzable chlorine group. 3 Epoxy resin has a content of hydrolyzable chlorine groups.
3. The method for continuously producing a laminate according to claim 1 or 2, wherein the content of hydroxyl groups in the α-diol group is 0.01 to 0.07% by weight. 4. Claims 1 to 4, characterized in that the epoxy resin composition contains 2 to 4 parts by weight of a curing agent and 0.1 to 0.5 parts by weight of a curing accelerator per 100 parts by weight of epoxy resin. A method for continuously manufacturing a laminate according to any of Item 3. 5 Epoxy resin has an epoxy equivalent of 180 to 700g/
5. The method for continuously producing a laminate according to any one of claims 1 to 4, wherein the bromine content is 0 to 50% by weight in eq. 6. The continuous production method of a laminate according to any one of claims 1 to 5, wherein the base material is a glass cloth. 7. The continuous production method of a laminate according to any one of claims 1 to 6, wherein the base material is a glass cloth having a thickness of 0.1 to 0.3 mm. 8. The method for continuously manufacturing a laminate according to any one of claims 1 to 7, characterized in that impregnation with the epoxy resin composition is performed while the base material is under reduced pressure. 9. Claim 1, wherein the prepreg is characterized in that the unimpregnated portion of the epoxy resin composition is less than 0.3% of the surface area of the base material, and the number of bubbles contained is 500 or less per square inch. 9. A method for continuously manufacturing a laminate according to any one of items 8 to 8. 10 When heating and pressurizing, the heating temperature increase rate of the prepreg is
10. The method for continuously manufacturing a laminate according to claim 1, wherein the process is carried out at a temperature of 100° C./min or higher. 11 The total amount of 1/2 of the hydroxyl group of the α-diol group and the hydrolyzable chlorine group is 0.01 to 0.01 of the epoxy resin.
An epoxy resin composition is prepared using an epoxy resin containing an α-diol group and a hydrolyzable chlorine group as a main component so that the concentration is in the range of 0.14% by weight, and this epoxy resin composition is impregnated into a base material. A long prepreg is created, and one or more sheets of long prepreg and a long metal foil are overlapped with each other so that the metal foil becomes the outermost layer and are continuously fed while heating and pressurizing them. Heat the metal foil to 50 to 250℃ higher than the prepreg before heating and pressing.
A continuous production method for laminated plates that involves heating them to high temperatures. 12 The epoxy resin is made of α-diol so that the total amount of 1/2 of the hydroxyl group of the α-diol group and the hydrolyzable chlorine group is in the range of 0.02 to 0.09% by weight of the epoxy resin.
Claim 11, characterized in that it contains a diol group and a hydrolyzable chlorine group.
Continuous manufacturing method of the laminate described in Section 1. 13. The continuous production method of a laminate according to claim 11 or 12, wherein the metal foil has a thickness of 5 to 35 μm. 14 The total amount of 1/2 of the hydroxyl group of the α-diol group and the hydrolyzable chlorine group is 0.01 to 0.01 of the epoxy resin.
An epoxy resin composition is prepared using an epoxy resin containing an α-diol group and a hydrolyzable chlorine group as a main component so that the concentration is in the range of 0.14% by weight, and this epoxy resin composition is impregnated into a base material. A long prepreg is created, one or more sheets of long prepreg and a long metal foil are overlapped with each other so that the metal foil becomes the outermost layer, and are continuously fed while being heated and pressurized. A method for continuously manufacturing a laminate, which comprises heat-treating a laminate obtained by heating and pressing at a temperature of 130°C to 200°C under no pressure. 15 The epoxy resin is made of α-diol so that the total amount of 1/2 of the hydroxyl group of the α-diol group and the hydrolyzable chlorine group is in the range of 0.02 to 0.09% by weight of the epoxy resin.
Claim 14, characterized in that it contains a diol group and a hydrolyzable chlorine group.
Continuous manufacturing method of the laminate described in Section 1.