JPH01299835A - Production of laminate - Google Patents

Abstract

PURPOSE:To obtain a laminate retaining a low permittivity, a low dielectric loss tangent and high heat resistance and having increased flame retardancy, by laminate-molding prepregs formed from a varnish containing a specified poly(aromatic cyanate), a flame retardant and a catalyst and base materials. CONSTITUTION:A varnish is prepared by mixing a poly(aromatic cyanate) of formula I with a flame retardant of formula II and a reaction catalyst for the poly(aromatic cyanate). Prepregs are formed by impregnating base materials with this varnish and laminate-molded. In the formulas, Ar is an aromatic, B is a 7-20C polycyclic aliphatic group, D is an active hydrogen-free substituent, q, r and s are each 0, 1, 2 or 3, q+r+s>=2, t is 0-4, and x is 0-5. As the catalyst, an organocobalt salt is particularly desirable.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for manufacturing a laminate used as a printed wiring board. [Background Art] In recent years, frequencies used in fields such as electronic industry, communications, and computers have shifted to a high frequency region such as MHz'l'GHz. In the insulating layer of printed wiring boards used in such high frequency ranges, it is necessary to have a smaller dielectric constant in order to shorten signal propagation delay, and a smaller dielectric loss tangent in order to reduce power loss. Ethylene 477a has a small dielectric constant and dielectric loss tangent for each desired purpose.
tjlF (Teflon) and poly-7enylene oxide (p
Attempts have been made to form an insulating layer using resins such as po).

[Problem to be solved by the invention]

However, when forming an insulating layer using these resins, the glass transition temperature (Tg) is as low as 180 to 200°C (the heat resistance is insufficient, and the reliability of the through hole may be affected, such as the occurrence of smear during through hole processing). There have been problems such as the inability to form a multilayer printed wiring board due to the inability to obtain a high level of The object of the present invention is to provide a method for manufacturing a laminate that can maintain its properties and also improve its flammability.

[Measures to Solve the Problem] The present invention provides a polyaromatic cyanate represented by the following formula (I), (OCN)r (wherein ^r is aromatic, and B is a C7-2° polycyclic ring). an aliphatic group of the formula: D is each independently a substituent containing no active hydrogen; q. r, s are each independently an integer of 0.!, 2 or 3;
However, the sum of qyrt8 is greater than or equal to 2. Each is an independent integer from 0 to 4*. X is a number from O to 5) A flame retardant represented by the following formula (I[), (wherein R and R' are aromatic or brominated aromatic substituents that do not contain active hydrogen. n is a positive number. ) A glazing method for laminated plates characterized by preparing a varnish by blending it with a polyaromatic cyanate reaction catalyst, impregnating a base material with this varnish to create a prepreg, and laminating and molding the prepreg. This is related. The present invention will be explained in detail below. As the polyaromatic cyanate represented by formula (I), those disclosed in Patent Application Publication No. 1988-500434 can be used. That is, this polyaromatic cyanate provides aromatic poly)+77 gin which is more stable against hydrolytic action and has excellent thermal stability than conventional poly) 97 gin. In the polyaromatic cyanate of formula (1) used in the present invention, the aromatic group Ar means any group containing an aromatic group, such as benzene, naphthalene, 7-enanthracene, 7-nthracene, or bicarbonate. Aromatic group, two or more aromatic groups bridged by alkylene moieties. Suitable examples include benzene, naphthalene, biphenyl, binaphthyl, and di-7enylalkylene groups, with benzene groups being particularly preferred. ~2° polycyclic aliphatic group B means an aliphatic group containing two or more lumps, and the polycyclic aliphatic group has one or more double bonds or triple bonds. May be included. Suitable polycyclic aliphatic groups include the following. Oo is present, and Dl is a C1-5 alkyl group. ), especially (a) (b) (c) (dHe) (f) (g) or (1)
Preferably, (a) (t)) (c
)(d)(1), particularly preferred is (a). D in formula (1) means all substituents that can be substituted on the organic hydrocarbon group, but substituents containing active hydrogen atoms are excluded. The active hydrogen atom means a hydrogen atom bonded to an oxygen, sulfur, or nitrogen atom.Each of the six formulas (1) is defined independently, for example,
Alkyl, alkenyl, alkynyl, 7-aryl, alkaryl, aralkyl, halo, alkoxy, nitro, carboxylate, sulfone, sulfide, carbonate, etc., preferably C3-1° alkyl, C. ~1° alkenyl, nitro, halo 7)'), CI-
. Furkyl % CI ~, alkynyl, bromo, chloro are most preferred. In addition, in formula (1), 1 is an integer from 0 to 4*, preferably an integer of 0.1 or 2, more preferably 0 or 1, and most preferably 0. Each t in I') is defined independently. Qs r, S is 0.1.2
or an integer of 3, optimally 1. qs rs
Each S is defined independently, but the sum of these is 2
It is set as above. Furthermore, X is a positive number ranging from 0 to 5*. Polyaromatic cyanates of formula (I) are found as mixtures of compounds in which X is θ to 5*, and X is defined as the average number of this mixture. A preferred embodiment of the polyaromatic cyanate of formula (I) is represented by the following formula. Therefore, aromatic polytriazine (polyaromatic ananate resin) obtained from polyaromatic cyanate of formula (1)
has a low dielectric constant (around C2, 78) and a low dielectric loss tangent (t
It has excellent properties as a resin constituting the insulating substrate of a printed wiring board, such as having an δ of about 0.003) and high heat resistance (lass transition temperature Tg of 250 or higher, open heat resistance of about 300° C.). Therefore, in the present invention, a 7-E/X-terminated tetrabromobisphenol A carbonated oligomer represented by formula (II) is further blended as a flame retardant to impart flame retardant properties required for printed wiring boards. be. In formula (n), R and (/R' are aromatic or brominated aromatic substituents that do not contain active hydrogen, for example, B" (R1 is B", CH3, C2H, etc., or a combination thereof. In the formula (n), n is an integer that is not particularly limited, but currently available ones are n = 10 to 3.
20 mixtures. The flame retardant effect of formula 0 (■), which can be used even if n is other than this, is determined according to Brfl, and is UL
In order to obtain flame retardancy at the standard level of 94V-0, the content of Br should be 10 to 15% by weight based on the total amount of the polyaromatic cyanate of formula (I) and the flame retardant of formula (n). % of the flame retardant. If the amount of the flame retardant is too large, problems may arise in heat resistance, so the upper limit is preferably set at 15% by weight. As a reaction catalyst for polymerizing the polyaromatic cyanate of formula (1), organic metal salts such as imidazoles, tertiary amines, organic cobalt salts such as cobalt naphthenate and cobalt octylate can be used, Organic cobalt salts are particularly preferred.The amount of the reaction catalyst is not particularly limited, but for example, when using organic cobalt salts as a reaction catalyst, depending on the desired gel time of the varnish (described later), The weight ratio of cobalt ion to the weight of group cyanate is 10 to 700 pp-
It is blended within a range of degrees. and the polyaromatic cyanate of formula (I) above, formula (n)
A varnish is prepared by dissolving a flame retardant, a reaction catalyst, etc. in an organic solvent. As an organic solvent, formula (I)
Aromatic hydrocarbons, alcohols, and ketones are not particularly limited as long as they dissolve the polyaromatic cyanate and the flame retardant of formula (II) and do not adversely affect the reaction.For example, toluene, 7setone, methyl ethyl ketone, dimethyl Formamide, methyl cellosolve, etc. can be used alone or in combination of two or more. The concentration of the varnish is generally adjusted so that the solid content is 50 to 70% by weight. However, when preparing prepreg for a*, the base material is not particularly limited, but it is common to use glass fiber woven or non-woven fabric, and this base material is impregnated with varnish and heated. dry. The amount of varnish 7 impregnated into the base material is preferably set so that the ratio of solid content (compound of formula (1) and compound of formula (II)) to the base material is 45% by weight or more. The dielectric constant level is affected by the resin content, and when the base material is made of EIF lath cloth, a dielectric constant of 4°0 or less can be achieved with impregnation of 45% by weight or more. If the base material is made of lath cloth, the dielectric constant will be 3.5 when impregnated with 45% by weight or more.
The following can be achieved: The heating and drying conditions when preparing prepreg are influenced by the amount of reaction catalyst blended, etc., but for example, when the heating temperature is 160°C, the desired prepreg can be obtained by setting the heating time for about 3 to 10 minutes. You can get the stroke del time. The stroke del time of prepreg varies depending on molding conditions, etc., but is generally about 2 to 10 minutes at 170°C. Then, by layering multiple sheets of prepreg prepared in this way, then layering metal foil such as copper foil on both or one side of the top and bottom, and molding this under heat and pressure, the polyaromatic cyanate in the prepreg polymerizes and hardens. A double-sided metal foil-clad laminate or a single-sided metal foil-clad laminate can be produced by laminating and bonding metal foil on both sides or one side of an insulating substrate. An inner layer printed wiring board can be created by etching the metal foil of this laminated board to form a circuit, and by stacking a plurality of inner layer printed wiring boards via a plurality of the above prepregs, the outermost layer is covered with metal foil. A multilayer printed wiring board can be created by stacking them and molding them under heat and pressure. The molding conditions are heating temperature 1
70℃~230℃, pressure 30~40kg at maximum pressure
It is common to set the time to about 90 to 120 minutes. [Examples] The present invention will be described in detail below with reference to Examples. A mixture of 80 parts by weight of a polyaromatic cyanate (XU-71787 manufactured by Dow Chemical Company) represented by the K1 nine-dimensional formula, in which R and R' are the formula (b) in the formula (It), and n is 10-20, was prepared. Take 20 parts by weight of each flame retardant (brominated carbonate oligomer; BC-58 manufactured by Great Lakes) (Br content is 11.74% by weight) and solidify them in a 1:1 mixed solvent of methyl ethyl ketone and methyl cellosolve. A varnish was prepared by stirring and dissolving the mixture so that its content was 60% by weight, and adding cobalt octylate as a reaction catalyst at a weight ratio of 300 ppm of cobalt ions to the polyaromatic cyanate. This varnish was impregnated into a 2116 type E lath cloth base material (Nitto Boseki M116E) so that the solid content (polyaromatic cyanate and flame retardant) was 45% by weight, and heated at 150°C.
A prepreg was prepared by heating and drying for 4 minutes. Next, we stacked four sheets of this prepreg and roughened both sides with a thickness of 70 μ on both the top and bottom #! Layer the foils and mold at a temperature of 170°C.
, laminated molding was carried out under the conditions of molding pressure 40 kg/am for 2.90 minutes, and after molding, the electrical connection was made 230
77 degrees Celsius for 2 hours to a thickness of 0.
A double-sided copper-clad laminate for a 4 am inner layer printed wiring board was obtained. Female milk L Poly7minobismaleimide resin (Kelimide 601 manufactured by Nippon Polyimide Co., Ltd.) was added to N so that the solid content was 60% by weight.
-A polyimide UF fat varnish was prepared by dissolving it in methyl-2-pyrrolidone. This varnish was impregnated into the same E terrace base material as in the example so that the resin content was 45% by weight,
A prepreg was prepared by drying in the same manner as in the example. Four sheets of this prepreg were stacked one on top of the other, and a layer of 70 μm was applied on both the top and bottom sides.
Thick double-sided roughened fI4 foils were layered and laminated molded under the same conditions as Example 1, and further heated at 200°C in an electrically open state.
, 77 turquoise under the conditions of 2 hours, thickness 0, 4
A double-sided copper-clad laminate for an 11 m inner layer printed wiring board was obtained. By etching the copper foil of the double-sided copper-clad laminate thus obtained to form a circuit, an inner-layer printed wiring board was created, and three inner-layer printed wiring boards were placed between each of the same three 18μ
Layer thick copper foil and laminated it under the same conditions as above,
Further, a multilayer printed wiring board having a circuit configuration of 8 layers and having a thickness of 2.4 mm was obtained by subjecting the product to 77 turrets at 200° C. for 2 hours. Only the polyaromatic cyanate (Dow Chemical Co., Ltd. i! The mixture was stirred and dissolved to a solid content of 60% by weight, and cobalt heptanoate was added thereto as a reaction catalyst at a weight ratio of 200 pp of cobalt ions to the polyaromatic cyanate resin to prepare a varnish. Thereafter, a prepreg was prepared in the same manner as in the example, and lamination molding and after-curing were performed in the same manner as in the example to obtain a double-sided copper-clad laminate for an inner layer printed wiring board having a thickness of 0.4 mm. The electrical properties, thermal properties, etc. of the laminates of Examples and Comparative Examples 1 and 2 obtained as described above were measured, and the results are shown in Barley. For barley, dielectric constant, dielectric loss tangent, twist resistance, and open heat resistance were measured based on JIS C6481. However, as seen in the results of the chart of the viscoelastic spectrum, the lath transition temperature of the example in which the insulating substrate was formed from aromatic borito-177 non-polymerized polyaromatic cyanate was compared to that of polyimide resin. It is confirmed that the dielectric constant and dielectric loss tangent are lower than those of Comparative Example 1 in which an insulating substrate was formed using 1. *In the example in which a flame retardant was blended with the polyaromatic cyanate, compared to the H of comparative example 2 in which no flame retardant was blended.
It was confirmed that the flame retardancy increased from the B level to the 94V-0 level, and it was also confirmed that the lath transition temperature and heat resistance temperature remained high without deterioration. [Effects of the Invention] As described above, in the present invention, a laminate is manufactured by blending and using the flame retardant of the formula (II) with the polyaromatic cyanate of the formula (1>). The low dielectric constant and dielectric loss tangent of the polyaromatic cyanate polymer ensure high high-frequency properties of the laminate, and the flame retardant grade of the laminate can be increased by adding flame retardants. At the same time, it is possible to maintain a high level of heat resistance.

Claims (1)

[Claims] (1) The polyaromatic cyanate shown in the following formula (I) has ▲mathematical formulas, chemical formulas, tables, etc.▼...Formula (I) (In the formula, A_r is aromatic, B is a polycyclic ring of C_7_ to_2_0 Formula aliphatic group. D is each independently a substituent containing no active hydrogen. q, r, and s are each independently an integer of 0, 1, 2, or 3, provided that the sum of q, r, and s is less than 2. is greater than or equal to 2. t is each independently an integer from 0 to 4. x is 0 to 4.
5) Flame retardants shown in the following formula (II), ▲There are mathematical formulas, chemical formulas, tables, etc.▼...Formula (II) (In the formula, R and R' are aromatic or A brominated aromatic substituent (n is a positive number) is mixed with a polyaromatic cyanate reaction catalyst to prepare a varnish, and a base material is impregnated with this varnish to create a prepreg, and this prepreg is laminated and molded. A method for manufacturing a laminate, characterized by: