JP3222689B2 - Manufacturing method of laminated board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electric insulating plate, and more particularly to a method for producing a laminated board used as an insulating substrate for a printed wiring board.

[0002]

2. Description of the Related Art A laminated board (hereinafter simply referred to as a laminated board) used as an insulating board for electric use, particularly a printed wiring board (hereinafter simply referred to as a "laminated board") is prepared by applying and impregnating a sheet-like fiber base material with an insulating material resin and heating the prepreg. The prepreg is manufactured by stacking a predetermined number of the prepregs and applying heat and pressure. Thermosetting resins such as phenolic resins, epoxy resins, and unsaturated polyester resins are mainly used as the insulating material resin. In the step of coating and impregnating the sheet-like fiber base material with the insulating material resin, a large amount of solvent is used.

[0003]

However, since a large amount of solvent is used in the step of coating and impregnating the sheet-like fiber base material with the insulating material resin, it is possible to prevent fires, explosions, and other disasters from occurring and to vaporize the solvent vapor. The installation and maintenance of facilities that take into account the prevention of environmental pollution caused by large amounts of money required a large amount of money, which put pressure on production costs.

It is known that dihydro1.3-benzoxazines are polymerized and cured by heating without producing volatile by-products (see Japanese Patent Application Laid-Open No. 49-47378). For the production of the laminate, a method using a solvent such as methyl ethyl ketone is employed. For this reason, due to the specialty of the material, a laminated board using a cured product of dihydro-1.3-benzoxazine as a matrix has not been put to practical use. The present invention provides a method for curing dihydro-1.3-benzoxazines,
It is an object of the present invention to provide a method for producing a laminated board without using a solvent, by utilizing a feature that polymerization and curing are performed without generating volatile by-product components.

[0005]

The present invention provides a compound represented by the formula
Dihydro-1.3-benzoxazines having two or more groups shown below (hereinafter referred to as dihydrobenzoxazine resins)
In the form of a sheet, and laminating the sheet and a predetermined number of fibrous sheet substrates, and heating and pressing the laminated sheet.

Embedded image In the formula, R ¹ is a phenyl group, a substituted phenyl group, a methyl group or a cyclohexyl group, and R ² is a hydrogen, a methyl group, an ethyl group or a phenyl group.

The dihydrobenzoxazine resin is a compound having at least one hydroxyphenylene group in which at least one of the ortho positions of the hydroxyl group is hydrogen in one molecule, a primary amine and formaldehyde, Primary amine is used in an amount of 0.2 to 1 mole per mole of a hydroxyl group in which at least one of the
0.9 mole of formaldehyde and 2 of primary amine
It is produced by reacting at a molar ratio of at least twice.

More specifically, a compound having two or more hydroxyphenylene groups in one molecule in which at least one of the ortho positions of the hydroxyl group is hydrogen (hereinafter, referred to as a compound having a reactive hydroxyphenylene group) and 1
The mixture with a tertiary amine is added to an aldehyde heated to 70 ° C. or more, and the mixture is added at 70 to 110 ° C., preferably 90 to 110 ° C.
Reaction at 100 ° C for 20 minutes to 2 hours, then 120 ° C
A dihydrobenzoxazine resin is obtained by drying under reduced pressure at the following temperature.

The primary amine and the formaldehyde are reacted at a ratio of at least 0.2 to 0.9 mol and at least twice the molar amount of the primary amine with respect to 1 mol of the hydroxyl group of the compound having a reactive hydroxyphenylene group. It is important to make it happen. When the amount of the primary amine is less than 0.2 mol, the number of dihydrooxazine rings becomes small, so that when the obtained compound is cured, only a cured product having a low crosslinking density and a small strength can be obtained. On the other hand, if the amount is more than 0.9 mol, the degree of elongation of the molecular chain is small and the crosslink density is small, so that 200 ° C.
If it exceeds, it is not preferable because of softening or thermal deterioration.

The amount of the primary amine to be added to the compound having a reactive hydroxyphenylene group can be determined as follows. That is, 1 mole of the same molar amount as all hydroxyl groups of the compound having a hydroxyphenylene group is used.
The amount of reacted hydroxyl groups in the compound having a hydroxyphenylene group was estimated from the weight of the product actually obtained by reacting the secondary amine, and the amount of the hydroxyl group capable of reacting in the compound having a hydroxyphenylene group was estimated, and calculated as the molar ratio described above. I do.

As the compound having two or more reactive hydroxyphenylene groups in one molecule, various compounds partially having a phenol nucleus can be used. Specifically, phenol novolak resin, resole resin, phenol modified xylene resin, alkylphenol resin,
Melamine phenol resin, phenol-modified polybutadiene and the like can be mentioned. These are not particularly limited, but those in which the ortho position of the hydroxyl group serving as a crosslinking point is unsubstituted are desirable in terms of the properties of the cured product.For example, in the case of a phenol novolak resin, the ortho ratio is small and the molecular weight is relatively small. It is preferred to use small so-called random novolaks. The above resin is a set of compounds having different numbers of reactive hydroxyphenylene groups in one molecule, and a part of the thermosetting compounds generated during the production are polymerized with each other.

Specific examples of the primary amine include methylamine, cyclohexylamine, aniline, substituted aniline and the like. If the aliphatic amine, the curing of the resulting thermosetting compound is fast, but the heat resistance of the cured product is slightly inferior,
When an aromatic amine such as aniline is used, the cured product obtained by curing the obtained thermosetting compound has good heat resistance, but cures slowly.

The thus obtained dihydrobenzoxazine resin is previously heated at 80 to 180 ° C., preferably at 12 ° C.
By heat-treating at 0 to 160 ° C., a part thereof is prepolymerized, and the curing speed and melt viscosity during molding are adjusted.

[0013] Vegetable oil-modified phenolic resins, epoxy resins, polyester resins, used for laminates
A thermosetting resin such as a vinyl ester resin or a polyimide resin may be added as a B-staged product or a cured product.
In addition, metal foils and the like are removed from the residual material and cut ears of a product formed of a printed circuit laminate such as a vegetable oil-modified phenolic resin, an epoxy resin, etc., pulverized into particles having a particle size of 150 μm or less, and mixed with 3 to 75%. It is also possible to form a sheet. In order to disperse these resin powders, it is preferable that the particle size is small, and usually the particle size is 100 μm or less, and optimally the particle size is 5 μm.
0 μm or less is desirable. These resin compositions are selected or improved depending on the required characteristics of the printed circuit laminate, and used.
In addition to these additives, if necessary, a plasticizer is added.

After synthesizing the dihydrobenzoxazine resin, the resin is heated under pressure using, for example, a coater for hot melt, and uniformly coated on a metal sheet or a heat-resistant resin sheet (eg, a fluororesin sheet). Make a sheet. The thickness of the sheet is appropriately adjusted depending on the material and thickness of the fibrous sheet substrate, good to the ^{120g / m 2 ~200g / m 2} , 140g / m 2 ~180g / m 2 is optimum.

As the fibrous sheet substrate, a sheet substrate generally used for a laminate can be used. paper,
Any of glass woven fabric, glass nonwoven fabric and the like can be used. These sheet substrates are preferably treated with a water-soluble phenol resin or a melamine-modified phenol resin for paper and with a silane coupling agent for glass substrates.

A structure in which a fibrous sheet substrate and a dihydrobenzoxazine resin sheet are appropriately laminated is covered with a release film, and a laminate is obtained by heating and pressing. A composite sheet in which a fibrous sheet substrate and a sheet of a dihydro-1.3-benzoxazine compound are pressure-bonded with a heating roll in advance may be used. If the fibrous sheet-like substrate is coated with a dihydrobenzoxazine resin, continuous molding is also possible. If a metal foil, for example, a copper foil is laminated in place of the release film, a metal-clad laminate can be obtained. As the metal foil, copper foil is usually used, but metal foil such as nickel foil or aluminum foil may be used depending on required characteristics.

[0017]

【Example】

Example 1 phenol 1.9 kg, formalin (37% water-soluble)
1.0 kg and 4 g of oxalic acid were charged into a 5 liter reactor and reacted at reflux temperature for 6 hours. Subsequently, the internal pressure was reduced to remove unreacted phenol and water. The obtained resin has a softening point of 84 ° C. (ring and ball method) 3 to polynuclear ratio 82/18.
(Peak area ratio according to gel-barrier chromatography).

1.70 kg (corresponding to 16 mol of hydroxyl groups) of the phenol novolak resin synthesized above and 0.93 kg (corresponding to 10 mol) of aniline were mixed and stirred at 80 ° C. for 5 hours to prepare a uniform mixed solution. 1.62 kg of formalin was charged into a 5 liter reaction vessel and heated to 90 ° C., and the mixed solution of the phenol novolak resin and aniline was added thereto. The mixture was kept at the reflux temperature for 30 minutes. The pressure was reduced for a time to remove the condensed water. A resin composition in which 71% of the hydroxyl groups capable of reacting were converted to dihydro-1.3-benzoxazine was obtained.

The method for calculating the amount of hydroxyl group capable of reacting is as follows. 1.70 kg of the phenol novolak resin
(Corresponding to 16 mol of hydroxyl groups) to 1.49 kg of aniline (1
(Equivalent to 6 mol) and 2.59 kg of formalin, and all the reactive hydroxyl groups were converted to dihydro-1.3.
-Benzoxazine conversion. The unreacted aniline and formalin and the residue obtained by removing the water of the reaction system, that is, the yield of the dihydrobenzoxazine resin is 3.34 kg. This corresponds to a product in which 14 mol of the hydroxyl groups of the phenol novolak resin have reacted and converted to dihydro-1.3-benzoxazine. From this, the resin composition obtained in the present example has 14 mol of reactive hydroxyl groups.
It can be seen that 10 mol (71%) of the compound was converted to dihydro-1.3-benzoxazine.

Example 2 1,2-butadiene (B-100, manufactured by Nippon Soda Co., Ltd.)
0) 0.92 kg, 3.30 kg of phenol and 1 g of p-toluenesulfonic acid were charged into a 5 liter reactor, and 8
The reaction was performed at 0 ° C. for 5 hours. After cooling and washing with water, unreacted phenol was removed by steam distillation to obtain 1.41 kg of a polybutadiene-modified phenol resin. The hydroxyl equivalent is 270 based on the weight of the added phenol.

The resulting polybutadiene-modified phenol resin (2.70 kg, corresponding to 10 mol of hydroxyl groups), 0.56 kg (corresponding to 6 mol) of aniline, and 0.97 kg of formalin
Using kg, a resin composition in which 73% of hydroxyl groups capable of reacting were converted to dihydro-1.3-benzoxazine was obtained in the same manner as in Example 1.

Example 3 Tung oil 0.50 kg, m-cresol 4.00 kg, p-
4 g of toluenesulfonic acid was charged into a 5 liter reaction vessel, and reacted at 80 ° C. for 5 hours. After cooling and washing with water, unreacted m-cresol was removed by steam distillation and tung oil / m-
0.82 kg of the cresol reactant was obtained. The hydroxyl equivalent is 280 based on the weight of the added m-cresol.

The obtained tung oil / m-cresol reactant
80 kg (corresponding to 10 mol of hydroxyl groups) of aniline 0.56
Using 0.6 kg (equivalent to 6 mol) and 0.97 kg of formalin, a resin in which 66% of hydroxyl groups capable of reacting were converted to dihydro-1.3-benzoxazine was obtained in the same manner as in Example 1.

Example 4 Xylene resin (Nikanol H, trade name, manufactured by Mitsubishi Gas Chemical Co., Ltd., average molecular weight: 557, reactive group equivalent: 96)
0.96 kg, 4.00 kg of phenol and 4 g of p-toluenesulfonic acid were charged into a 5 liter reactor,
For 5 hours. After cooling and washing, unreacted phenol was removed by steam distillation to obtain 1.12 kg of a phenol-modified xylene resin. 0.31 kg of phenol substituted with oxymethylene group based on unreacted phenol residue
Met. The hydroxyl equivalent of the xylene resin synthesized from this becomes 340.

2. The obtained xylene-modified phenolic resin
40 kg (corresponding to 10 mol of hydroxyl groups), aniline 0.28
kg (corresponding to 3 mol) and 0.49 kg of formalin, a resin product was obtained in which 79% of hydroxyl groups capable of reacting were converted to dihydro-1.3-benzoxazine by the same operation as in Example 1.

Production of Laminated Plate 1 The obtained four kinds of dihydrobenzoxazine resins were flowed on a steel belt and cooled to form sheets. The sheet weighed 146 g / m ² . Separately, a water-soluble melamine-modified phenol resin was applied to kraft paper having a thickness of 0.2 mm so that the resin content was 15% by weight. Pile 8 sheets of kraft paper and dihydrobenzoxazine resin sheet,
A copper foil with a thickness of 18 μm is layered on both sides, set between head plates, and pressed at a temperature of 170 ° C. and a pressure of 8 MPa by a multi-stage press.
Heated and pressurized for minutes.

Production of Laminated Board 2 A pulverized powder obtained by pulverizing a paper-phenol resin laminated board (FR-2 board from which copper has been removed) with the obtained four kinds of dihydrobenzoxazine resins to a particle diameter of 50 μm was applied to the resin. 20% by weight was added, mixed well, flowed on a steel belt and cooled to form a sheet. The sheet weighed 146 g / m ² . Hereinafter, a laminated plate was obtained in the same manner as in the production of the laminated plate 1.

Manufacture of Laminated Plate 3 A water-soluble melamine-modified phenolic resin was added with 10% by weight of a crushed powder obtained by pulverizing a paper phenolic resin laminated plate (FR-2 plate from which copper was removed) to a particle size of 50 μm. And mixed well. This water-soluble melamine-modified phenol resin was applied to kraft paper having a thickness of 0.2 mm so that the resin content was 15% by weight. Hereinafter, a laminated plate was obtained in the same manner as in the production of the laminated plate 2.

Manufacture of laminated board 4 Paper phenol resin laminated board (FR-2 board from which copper was removed)
A water-soluble melamine-modified phenolic resin was applied to kraft paper having a thickness of 0.2 mm in which 10% by weight of ground powder having a particle size of 50 μm was incorporated, so that the resin content was 15% by weight. Hereinafter, a laminated plate was obtained in the same manner as in the production of the laminated plate 2.

Comparative Example Tung oil and phenol were reacted under an acidic catalyst.
% Paraformaldehyde was added thereto and reacted under an alkali catalyst to form a resol. Thus, a tung oil-modified phenol resin having a tung oil modification rate of 39% was obtained. This tung oil modified phenolic resin 100
25 parts by weight of tetrabromobisphenol A diglycidyl ether was blended with the parts by weight and dissolved in methyl ethyl ketone to obtain a varnish for impregnation. A 0.2 mm thick kraft paper is coated with a water-soluble melamine-modified phenolic resin so as to have a resin content of 15% by weight and dried, and then the impregnating varnish is applied so that the resin adhesion amount becomes 53% by weight. Was impregnated and dried to obtain a prepreg. Eight prepregs thus obtained are combined with copper foil with an adhesive and stacked at a temperature of 170 ° C. and a pressure of 8M.
The laminate was obtained by heating and pressing at 90 Pa for 90 minutes.

The obtained laminate was examined for heat resistance in air, weight loss on heating, water absorption and insulation resistance. Table 1 shows the results. Aerial heat resistance is the time it takes for blistering to occur in a drier at 200 ° C. Heat loss is the weight change before and after holding in a dryer at 200 ° C. for 10 minutes. The water absorption was measured at 50 ° C for 24 hours.
The percentage change in weight before and after holding for 24 hours in water at ° C. The insulation resistivity was determined by removing the copper foil by etching and keeping it in boiling water for 2 hours.
5 is a reading of an insulation resistance meter when a taper pin of the insulation resistance meter is inserted into two holes having a diameter of 5 mm and a DC voltage of 500 V is applied for 1 minute.

[0032]

[Table 1] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Test items Laminated board 1 Laminated board 2 Laminated board 3 Laminated plate 4 Comparative example ──────────────────────────────────── Heat resistance in air (min) 60 45 40 38 30 Loss on heating (%) 0.10 0.18 0.15 0.20 0.35 Water absorption (%) 0.65 0.73 0.70 0.75 0.70 Insulation resistance (Ω) × 10 ⁸ 5 3 1 3 2 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

[0033]

According to the method of the present invention, the benzoxazine resin can be molded without using a solvent, taking advantage of the fact that a low-molecular-weight reaction by-product is not produced when the resin is cured. ing.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI B29K 105: 08 B29K 105: 08 105: 22 105: 22 461: 04 461: 04 (72) Inventor Yasuyuki Hirai Shimodate, Ibaraki 1500 Ogawa, Shimodate Plant, Hitachi Chemical Co., Ltd. (56) References JP-A-6-345898 (JP, A) JP-A-2-69567 (JP, A) JP-A-54-3166 (JP, A) JP-A-49-47678 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 43/18-43/20 B29C 70/04-70/06 B32B 27/00-27 / 42 C08J 5/24 C08L 61/04-61/14 C08L 79/00 C08G 73/00 C08G 14/00-14/06

Claims (5)

(57) [Claims] 1. A sheet of a dihydro-1.3-benzoxazine having at least two groups of the formula 1 in a molecule,
A method for manufacturing a laminate, comprising laminating a predetermined number of fibrous sheet base materials with the sheet and heating and pressing. Embedded image In the formula, R ¹ is a phenyl group, a substituted phenyl group, a methyl group or a cyclohexyl group, and R ³ is a hydrogen, a methyl group,
It is an ethyl group or a phenyl group. 2. A method for producing a laminate, wherein the dihydro1.3-benzoxazine is dihydro1.3-benzoxazine obtained by reacting formalin and a primary amine with a phenol resin. 3. A composition comprising a thermosetting resin powder mixed with a dihydro-1.3-benzoxazine having two or more groups represented by the following formulas in the molecule into a sheet, and the sheet and a predetermined number of fibers A method for producing a laminate, comprising laminating a sheet base material and heating and pressing. 4. The method for producing a laminate according to claim 3, wherein the thermosetting resin powder is a powder obtained by pulverizing a laminate for electric use. 5. The method for producing a laminate according to claim 1, wherein a predetermined number of fibrous sheet substrates are stacked, and a metal foil is stacked on the outside thereof and heated and pressed.