JPS63159594A - Production of primary treated paper for electric insulating laminate - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to primary treated paper for electrical insulating laminates, particularly paper-based synthetic resin electrical insulating paper with excellent dimensional stability, punching workability, electrical properties, and heat resistance. The present invention relates to a method for producing primary treated paper for laminates.

[Conventional technology]

Laminate base paper is processed into electrically insulating laminates by laminate manufacturers by impregnating and drying a synthetic resin face such as phenol resin using a horizontal or vertical impregnating machine equipped with a hot air drying device, followed by thermoforming and processing into electrical insulating laminates, which are mainly used for printed wiring. They are used as printed wiring boards in a wide range of fields such as consumer and industrial electronic equipment, but in recent years, as electronic equipment has become smaller, lighter, and more sophisticated, the usage conditions for printed wiring boards have become harsher, and laminates have become more demanding. There is a growing tendency for the physical properties required of base paper to become more sophisticated.

In particular, the dimensional stability, low-temperature punching processability, and electrical properties of electrically insulating laminates are required to accommodate high-density wiring.

There is a need for laminated board base paper with good heat resistance.

Conventionally, bleached kraft pulp paper has been used as a base paper for laminate boards made from wood pulp, and although it has good dimensional stability, it has poor low-temperature punching processability and has problems as a base paper for laminate boards for high-density wiring. Ta.

In addition, although Kotton linter paper made from Kotton linter, a non-wood pulp, has better punching workability, electrical properties, and heat resistance than bleached kraft pulp paper,
Due to its poor dimensional stability, it is not suitable as a base paper for laminate boards for high-density wiring.

As a laminate for high-density wiring, the dimensional stability of bleached kraft pulp paper and the low-temperature punching processability of Kotton linter paper are recommended.
The emergence of a base paper that has both electrical properties and heat resistance, or a base paper that has even higher performance in terms of dimensional stability, is awaited.

On the other hand, on the synthetic resin side for electrical insulation laminates.

Although studies have been made to satisfy the above-mentioned quality requirements by conventional methods such as modification of resins and blending of additives, the present situation is that satisfactory results have not yet been obtained. Japanese Patent Applications No. 133091/1982 and No. 134381/1988 disclose methods that can satisfy the above requirements, but the dimensional stability is comparable to conventional bleached kraft pulp paper.

[Problem that the invention seeks to solve]

The present invention provides a primary treated paper for electrical insulating laminates that has good low-temperature punching workability, electrical properties, and heat resistance required for high-density wiring electrical insulating laminates, and has particularly excellent dimensional stability. It is something to do.

[Means for solving problems]

As a result of intensive studies to solve the above-mentioned problems, the present invention has been developed as a result of a manufacturing process for primary treated paper for electrically insulating laminates obtained by applying a water-soluble thermosetting synthetic resin to base paper for laminates and drying it. In.

It has been discovered that this object can be achieved by using a primary treated paper for electrically insulating laminates, which is characterized by drying while suppressing shrinkage in the direction perpendicular to the running direction of the coated paper.

Note that the term "applied paper" as used herein refers to the paper immediately after the application of the water-soluble thermosetting synthetic resin for primary treatment (before drying), and the paper after the application has been further dried is defined as the primary treated paper.

The present invention will be explained in more detail. Laminated board base paper can be used as the base paper for laminated boards, but if it has the same amount of impurities as bleached kraft pulp paper and the power source power of the water immersion liquid, the material pulp material and cooking method may be used. There are no particular restrictions on the bleaching method.

There is no particular restriction on the pulp furnace water level when making the base paper for laminates used in the present invention, but in order to improve the permeability of the resin into the base paper for laminates, it is necessary to
It is preferable that it be beaten relatively lightly, such as mNGSF or higher.

There are no particular restrictions on the basis weight or density of the base paper for laminated boards, but there are limitations on workability when processing them into laminated boards.

Basis weight 60-280 g/r considering productivity etc.
A d-density of about 0.4 to 0.7 g/ni' is suitable.

As the water-soluble thermosetting synthetic resin for primary treatment applied to the laminate base paper, water-soluble thermosetting synthetic resins with a relatively low degree of polymerization can be used. Typical examples include phenolic resin, epoxy Examples include resin and melamine resin,
As the water-soluble phenol resin, resol type phenol resin or phenol resin derivatives can be used, but the water-soluble phenol resin is not limited thereto.

As a water-soluble epoxy resin, Japanese Patent Application No. 133091/1986
Mono(or poly)alkylene glycol polyglycidyl ethers represented by those listed in No.

Mono(or poly)alkylene glycol monoglycidyl ether and the like can be used alone or in combination.

Examples of catalysts for water-soluble epoxy resins include sodium hydroxide, potassium hydroxide, zinc borofluoride, magnesium borofluoride,
chloride! ! (rV), quaternary ammonium salt.

Tertiary amines, imidazole compounds, boron trifluoride, etc. can be used. In addition, as curing agents, amines such as aliphatic polyamines, aromatic polyamines, secondary and tertiary amines, acid anhydrides such as phthalic anhydride, synthetic resin initial condensates such as phenol resins and melamine resins, other polyamide resins,
Dicyanamide etc. can be used.

As the water-soluble melamine resin, various methylolated products and derivatives such as methylolated products partially converted into alkyl ethers can be used. - Add filler as necessary to the water-soluble thermosetting synthetic resin for subsequent treatment.

Pigments, dyes, plasticizers, flame retardants, etc. can also be blended as appropriate.

The solvent may be either water alone or a mixed system of water and an organic solvent such as an alcohol, but in a mixed system, it is preferable that the proportion of water is large for the reasons stated in the section of the effect.

The ratio of the water-soluble thermosetting synthetic resin for primary treatment in the primary treated paper for electrical insulating laminates is 1 to 20%, and the amount of volatile matter during the secondary treatment is preferably about 1 to 15%.

Conventionally, the method of applying water-soluble thermosetting synthetic resin for primary treatment to the base paper for laminates is to apply it to the base paper for laminates using various impregnating heads in the state of water or a mixed solution of water/organic solvent, and then apply it to the base paper for laminates in a horizontal or vertical manner. This type is dried using hot air drying equipment. In this case, the applied paper shrinks freely in the direction perpendicular to the running direction.

In the present invention, in order to suppress the shrinkage of the applied paper in the direction perpendicular to the running direction, drying is performed with tension applied also in the perpendicular direction. As an actual method, for example, shrinkage in the direction perpendicular to the running direction can be suppressed by drying the coated paper in a multi-tube cylinder dryer or Yankee dryer using a single canvas or conventional canvas in which the paper is accompanied by a carrier. Become. The application means may be on-machine (paper machine) or off-machine (impregnation machine, coater, etc.).

Next, resins for laminates to be impregnated into the primary treated paper for electrical insulating laminates to make prepregs include phenol resin, melamine resin, diallyl phthalate resin, epoxy resin,
Synthetic resins such as unsaturated polyester resins are applicable.

The primary treated paper for laminates of the present invention is impregnated with the synthetic resin face to form a prepreg, which is then laminated and molded under heating to obtain an electrically insulating laminate. A known method can be used for heat forming. The resin content of the prepreg is preferably in the range of 40 to 65%.

Fillers, pigments, and dyes are added to synthetic resins as necessary.

Plasticizers, N fuel agents, etc. can also be blended as appropriate.

Note that a metal foil-clad laminate can also be obtained by placing metal foil on one or both sides of the laminate made of the prepregs and performing heating lamination molding.

[Effect]

Good dimensional stability in electrical insulating laminates can be achieved by using primary treated paper for electrical insulating laminates in which a water-soluble thermosetting synthetic resin is applied in the form of an aqueous solution to the laminate base paper and then heated and dried. It is possible to improve low-temperature punching workability, electrical properties, and heat resistance while maintaining
No. 91, Japanese Patent Application No. 134381/1981). This means that water-soluble thermosetting synthetic resins with active groups such as methylol groups and epoxy groups are applied to the base paper in the form of an aqueous solution and then heated and dried. This is thought to be the result of the presence of the curable synthetic resin, which improves the affinity (adhesion) with the synthetic resin that is impregnated later and promotes the integration of the base paper and the synthetic resin as a composite material.

In the manufacturing process of primary treated paper for electrical insulating laminates obtained by applying a water-soluble thermosetting synthetic resin, the present inventors have developed a method for drying while suppressing shrinkage in the direction perpendicular to the running direction of the applied paper. It has been discovered that by using the primary treated paper obtained by the above method, the dimensional stability of electrically insulating laminates can be further significantly improved while maintaining good electrical properties and low-temperature punching workability. This is thought to be because the paper coated with a water-soluble thermosetting synthetic resin was tension-dried and its internal stress was increased, resulting in a smaller amount of expansion and contraction in response to thermal changes.

〔Example〕

An example of the present invention and a corresponding comparative example will be shown below.

Example 1 Commercially available resol type water-soluble phenol resin, trade name J
-303 [manufactured by Dainippon Ink & Chemicals (■)] was dissolved in water to prepare a treatment liquid. This treatment liquid has a basis weight of 135g/rr? of bleached kraft pulp paper on the paper machine.

By heating and drying with a Yankee dryer, a primary treated paper coated with a water-soluble phenolic resin with a coating rate of 110% and a volatile content of 25% was obtained.This primary treated paper was coated with a commercially available alcohol-soluble tung oil-modified phenolic resin [trade name: BLS-31].
22: Impregnated with [manufactured by Showa Kobunshi ■].

It was dried to produce a prepreg. Next, 8 sheets of prepreg and 1 sheet of copper foil with adhesive (thickness 35M) were laminated, and heated at 155℃.
loOkg/cd, hot pressure molded under the conditions of 60 minutes, cooled for 30 minutes under pressure, resin impregnation rate th350
%.

A single-sided copper-clad electrical insulating laminate having a thickness of 1.6 m was obtained.

A: Weight of untreated base paper (g/Po) B: Amount of primary treated paper pattern coated with water-soluble thermosetting synthetic resin (g/Po)
Weight (g/) of C knee-treated paper after heating at 150°C for 10 minutes
rrr) D = Weight of electrically insulating laminate (g / rrr) n: Number of sheets of laminate base paper laminated per electrically insulating laminate A single-sided copper-clad electric sheet with a resin content of 50% and a board thickness of 1.6 m was applied in the same manner as in Example 1. An insulating laminate was obtained.

Example 3 The treatment solution used in Example 1 was applied to bleached kraft pulp paper with a basis weight of 135 g/rrr using a conventional impregnation head, and then heated and dried using a multi-tubular cylinder using a conventional canvas. In the same manner as above, a single-sided steel-clad electrical insulating laminate having a resin content of 50% and a thickness of 1.6 ma+ was obtained.

Example 4 100 parts by weight of ethylene glycol diglycidyl ether, which is a water-soluble epoxy resin, and 1 part by weight of zinc borofluoride as a catalyst
parts by weight are dissolved in water to prepare a treatment liquid.

This treatment liquid was applied to cotton linter paper with a basis weight of 135 g/m on a paper machine, and then heated and dried using a Yankee dryer to obtain a primary treated paper coated with water-soluble epoxy resin with an application rate of 8% and a volatile content of 3%. After obtaining the resin content was 50% in the same manner as in Example 1.

A single-sided steel-clad electrical insulating laminate having a thickness of 1.6 m was obtained.

Example 5 Trimethylolmelamine, which is a water-soluble melamine resin, is dissolved in water to prepare a treatment liquid. This treatment liquid has a basis weight of 135g/r.
RR bleached kraft pulp paper is coated on a paper machine and heated and dried in a multi-tubular cylinder using conventional canvas to obtain primary treated paper coated with a water-soluble melamine resin with a coating rate of 10% and a volatile content of 5%. Thereafter, a single-sided copper-clad electrical insulating laminate having a resin content of 50% and a thickness of 1.6 mm was obtained in the same manner as in Example 1.

Comparative Example 1 The treatment liquid used in Example 1 was applied to bleached kraft pulp paper with a basis weight of 135 g/rrr using an impregnation machine (coater), and the process was carried out in the same manner as in Example 1. A single-sided copper-clad electrical insulating laminate having a resin content of 50% and a thickness of 1.61 cm was obtained.

Comparative Example 2 A resin-containing product was prepared in the same manner as in Example 4, except that the treatment liquid used in Example 4 was applied to cotton linter paper with a basis weight of 135 g/rrr using an impregnating machine, and then heated and dried using a horizontal hot air dryer. A single-sided steel-clad electrical insulating laminate with a steel coating ratio of 50% and a thickness of 1.6 mm was obtained.

Comparative Example 3 A resin-containing paper was prepared in the same manner as in Example 5, except that the treatment liquid used in Example 5 was applied to bleached kraft pulp paper with a basis weight of 135 g/rrr using an impregnation machine, and the paper was heated and dried using a horizontal hot air dryer. A single-sided steel-clad electrical insulating laminate with a thickness of 50% and a thickness of 1.6 m was obtained.

The results of the above examples and comparative examples are summarized in the table.

Note that MD refers to the running direction, and CD refers to a direction perpendicular to the running direction.

``1 Elongation in water: J, TAPPI paper pulp test method Na
The elongation after immersion in water for 1 hour was measured using a 200 x 15 m test piece according to the 27-78A method.

112 Warp: 20 (!l) according to JIS-C6481
Measurements were made using a corner single-sided copper-clad laminate.

1. Punching workability: The distance between the die hole walls is 0.8°1.
0.1.2.1.6 A pair of round holes with a diameter of 1.0.1.2.1.7.2.1 and 1 square
Equipped with a pair of 2m square holes, the clearance on one side between the punch and die is 0. The surface temperature of the laminate was punched out at room temperature, 35°C, and 55°C using a test mold with O5nm, and the condition of the surface, holes, and cut edges after punching was judged according to ASTM 0617, and was judged as excellent, good, or good. Evaluation was made on a four-level scale of fair and poor.

l Insulation resistance, water absorption rate: Measured according to JIS-6481.

〔Effect of the invention〕

As is clear from the table, the quality of the primary treated paper to which the water-soluble thermosetting synthetic resin was applied by the drying method of the present invention was determined by the tension in the direction perpendicular to the running direction.

Since the applied paper is dried with suppressed shrinkage in the orthogonal direction, the elongation in water is smaller and the Young's modulus is higher than that of paper dried using a normal hot air drying method. In addition, the quality of the electrical insulating laminate remains good in electrical properties and punching workability, and has even better dimensional stability (warpage) than those dried by the hot air drying method. Therefore, the industrial significance of the subsequent treatment for electrically insulating laminates of the present invention is extremely great.

Patent applicant: Sanyo Kokusaku Pulp Co., Ltd. [Yuu Procedural amendment June 3, 1986

Claims (1)

[Scope of Claims] 1. In the manufacturing process of primary treated paper for electrically insulating laminates obtained by applying a water-soluble thermosetting synthetic resin to base paper for laminates and drying it, a process that runs perpendicular to the running direction of the coated paper A method for producing primary treated paper for electrical insulating laminates, which is characterized by drying while suppressing directional shrinkage. 2. The method for producing a primary treated paper for electrically insulating laminates according to claim 1, wherein the water-soluble thermosetting synthetic resin is a phenolic resin. 3. The method for producing a primary treated paper for electrical insulation laminates according to claim 1, wherein the water-soluble thermosetting synthetic resin is an epoxy resin. 4. The method for producing a primary treated paper for electrically insulating laminates according to claim 1, wherein the water-soluble thermosetting synthetic resin is a melamine resin.