FI105490B - Elimination laminate, process for its preparation, and base paper therefor - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to an electrical insulating laminate which contains a 5 core paper of sulphate pulp impregnated with a synthetic resin. The invention further relates to a process for making such a laminate and to said base paper for laminate.

Printed circuit boards commonly use an electrical insulating laminate containing a base paper impregnated with and processed with synthetic resin lacquer. In recent years, 10 has been the desired laminate base paper with good puncture quality, dimensional stability, heat resistance, etc. to meet the requirements of high density wiring.

Nowadays, bleached sulphate pulp is generally used for the base paper of the laminate, which is based on wood. The laminate using this base paper has excellent dimensional stability but has poor puncture quality at low temperature, heat resistance and electrical properties. Similarly, laminate base paper using dissolving pulp or non-wood pulp fibers has poor dimensional stability compared to laminate using bleached sulphate pulp base paper and is not suitable for high density wiring board.

Ξ 20 As disclosed in Japanese Unexamined Patent Publication No. Sho 60-79952, it is known that improving the purity of cellulose, represented by the content of alpha cellulose in the base paper, improves the heat resistance, electrical properties and puncture quality of the laminate. In addition, according to Japanese Unexamined Patent Publication No. 2-175,996, there is also known a method of reducing the amount of parts soluble in 10% KOH in the pulp during the cooking process. and heat resistance while maintaining dimensional stability. However, a method which improves the properties of the base paper of the laminate, thereby improving its heat resistance and electrical properties by studying the pulp bleaching process, is not known.

·: * ·: 30 On the other hand, Japanese Unexamined Patent Publication No. Sho 62 - 191 597 discloses a technique for providing a laminate base paper with increased electrical insulation resistance by reducing the amount of chlorine ions, etc., in the laminate. * '*. the basic paper. The method disclosed herein for reducing chlorine ions provides a method of reducing the ions in the water used during pulping using an ion exchange resin or a method for removing ions by intensifying pulp washing. However, removal of chlorine ions alone does not improve heat resistance, although electrical properties may be improved. In addition, a technique which reduces the amount of soluble solids to 10% KOH in the pulp while reducing the amount of chlorine ions in the base paper pulp by improving the bleaching process is not known.

The present inventors have paid attention to the pulp bleaching process and have found that by bleaching without using chlorine or chlorine-based bleaching chemicals in the bleaching pulp pulp bleaching process, it is possible to produce a laminate with high heat resistance and electrical stability and due to these properties.

The electrical insulating laminate according to the invention is thus characterized in that the sulphate pulp used for its base paper has been bleached by a chlorine-free bleaching process involving microbial or enzymatic treatment to reduce the residual chlorine content of the pulp and 10-15% KOH soluble constituents.

Non-chlorinated bleached pulp used in the present invention means pulp bleached without the use of chlorine-based chemicals such as chlorine, chlorine dioxide and hypochlorite and using bleaching chemicals as oxygen, ozone, hydrogen peroxide, sodium hydroxide, etc. It has been found that as an effective pre- or post-treatment in such a chlorine-free bleaching process.

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Exemplary enzymes include hemicellulose lysis type enzymes such as xylanase, mannanase, arabinosidase, xylosidase and mannosidase, or lignin lysis type enzymes such as lignin peroxidase, which is lysine-degrading, and is lysed by manganese. Mikrobi1; those with pulp bleaching ability can be used in the body. Examples include Coriolus vericolor, Lentzites betuluua, Pleurotus ostreatus and Phane-rochaete chrysosporii, which are known as lignin-degrading fungi and, in addition, SKB-207 (FERM P-13353), which is isolated as a microbial having a whitish characteristic.

t * · In this way, a mass with significantly less residual chlorine ions and reduced solubility in 10% KOH can be obtained.

♦ · · ♦ «· '« · · 3 105490

By making paper on a paper machine using pulp obtained by a chlorine-free bleaching process, the target laminate base paper can be obtained. Although the degree of pulp grinding in the manufacture of laminate base paper is not particularly limited, relatively light refining of 450 ml CSF or greater is desirable to achieve good penetration of the resin into the laminate base paper. The basis weight and density of the laminate base paper are not particularly limited, but a basis weight of between 80 and 300 g / m and a density of about 0.4 to 0.8 g / cm are desirable, considering workability, productivity, etc., when processed into a laminate.

If necessary, filler, pigment, dye, reinforcing agent, flame retardant, etc. may be blended or added to the base paper of the laminate. Furthermore, the method of their addition is not particularly limited, it is possible to appropriately select the internal addition to the base paper and / or As resins for use in laminate for the preparation of precursor by impregnating this laminate base paper, synthetic resins such as phenolic resin, melamine resin, diallyl phthalate-15 resin, epoxy resin and unsaturated polyester resin are mentioned.

Said synthetic resin lacquer is impregnated into the base paper of the laminate to make a precursor and these precursors are superimposed and cast into an insulating laminate under heat and pressure. In the present case, methods known in the art for impregnation, drying and casting by hot pressing may be used. If necessary, a filler, pigment, dye, plasticizer, flame retardant, etc. may also be suitably blended into the resin for the pre-impregnation.

* · • · · • · · …….

In addition, if hot molding is accomplished by placing a metal foil on one or both sides of a laminate body consisting of the above-mentioned superficial pre-impregnates, a metal foil-coated laminate may also be obtained.

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The process for producing the electrical insulating laminate according to the invention is characterized in that the sulphate pulp is bleached by a chlorine-free bleaching process which involves microbial or enzymatic treatment, the base paper is bleached and the resulting base paper is incorporated into the hot pressing lamella.

The invention further comprises a base paper for electrical insulating laminate wherein the pulp is bleached by a chlorine-free bleaching process involving microbial or * * enzyme treatment to reduce the residual chlorine content of the pulp and the content of ingredients soluble in 10% KOH "", and has a pulverization degree of up to 4 105490 and 450 ml CSF paper resin. base paper wherein the sulphate pulp has been bleached by a chlorine-free bleaching process involving microbial or enzymatic treatment to reduce the residual chlorine content and the content of 10% KOH soluble constituents, and wherein the paper has a basis weight of between about 80 and about 300 g / m 2; 4-0.8 g / cm3 as a paper laminate for machinability.

In the bleaching process comprising a microbial or enzyme-free bleaching process, the base paper containing bleached sulphate pulp is useful according to the invention, in particular for electrical insulating laminates forming a printed circuit board.

EXAMPLE The details of the present invention will now be described by way of example but are not limited thereto.

Example 1

Bleaching was performed using the bleaching order shown in Table 1. In contrast to the unbleached hardwood pulp sulphate pulp (kappa number 16.0), bleach was bleached with oxygen. The bleaching conditions were as follows: pulp consistency 20%, oxygen pressure 490 kPa, treatment temperature 95 ° C, treatment time 40 min and addition rates 2% and 0.5% by weight of sodium hydroxide and magnesium carbonate at the same melting point.

«I« «» '; Next, the oxygen bleached pulp obtained was sterilized at 120 ° C

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at 15 minutes, a fungal suspension of SKB-207 (FERM P-13353) was implanted. After adjusting the pulp consistency to 20%, it was cultured for 7 days at 30 ° C and then the pulp was washed with sufficient water.

To this sponge treated pulp was added 1.5% sodium hydroxide by weight and water to bring the pulp to 10% consistency and the pulp was treated. then for 40 minutes at 70 ° C. After washing the pulp with sufficient water, it was subjected to hydrogen peroxide treatment.

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The conditions this time were: 10% pulp consistency, processing temperature. Sat. 60 ° C, treatment time 120 minutes and addition amounts of hydrogen peroxide and sodium hydroxide of 2% and 0.5% by weight, respectively.

t 1 • 1 · ·., ..: The whiteness of the pulp obtained by this chlorine-free bleaching process was 85.9%.

• · 5 105490 This pulp is to be applied to the legs by hand making a base paper for laminate having a basis weight of 135 g / m 2 and a density of 0.5 / cm 3. This base paper was impregnated with a commercial alcohol soluble phenolic resin (trade name BLS-3122, manufactured by Showa Highpolymer Co., Ltd.) and dried to make a pre-impregnator. After this, 8 sheets of pre-impregnators and 1 sheet of adhesive coated copper foil (thickness 35 microns) were stacked and cast by hot pressing at 155 ° C, 9810 kPa and 60 minutes. After cooling the assembly for 30 minutes while maintaining the pressurized state, a copper-coated laminate with a 50% resin content and a thickness of 1.6 mm was obtained on one side.

10 * (Laminate weight) - (Base paper weight) 'Resin content (%) = -x 100 (Laminate weight) 15 Comparative Example 1

The same unbleached hardwood sulphate pulp as in Example 1 was bleached using the chlorine-based bleaching sequence shown in Table 1.

Comparative Example 2

The same unbleached hardwood sulphate pulp as in Example 1 was bleached using the chlorine-free bleaching sequence shown in Table 1 without any microbial treatment.

• · V ·: These pulps were obtained by hand making laminate base papers having a basis weight of 135 g / m 2 and a density of 0.5 g / m 2. Using these base papers, copper-coated laminates were obtained on the other side in the same way as in the pre-25 mark 1.

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table 1

Bleaching Conditions in Example and Comparative Examples

Bleaching Bleaching Conditions Example 1 Comparison-Comparative Conditions e.g. 1 e.g. 2

Oxygen Oxygen pressure, kPa 490 Not performed 490 |

Addition rate,% υ 2,52) 2,52)

Paste consistency, 20 20% Temperature, ° C 95 95 __Time, min__40___40

Microbial Species SKB-207 Not Performed Not Performed Temperature, ° C 30 __ Time, min__7___

Chlorine Addition,%} Not Direct 3.0 Not Direct

Pulp consistency, 3%% Temperature, ° C 50 _ Time, min___30__ I Hypoclonal Addition,% l) Not applicable 1.7 No performance Pulp consistency, 10%% Temperature, ° C 45 __Time, min_____60__

Alkali Addition,% 1.5 2.0 2.0

Mass consistency, 10 10 10:% ···. Temperature, ° C 70 60 60 .1 * 1 Time, min 40 60 60 • · · • • «

Chlorine Addition% No direct 0,5 No direct mass Paste consistency 10%% Temperature, ° C 75 __Time, min 120____

Hydrogen peroxide Addition,% 1} 2.53) Not performed 2.53) Cid Mass consistency, 10 10 ·: ·· *:% ·: · *: Temperature, ° C 60 60 ·. Time, min 120 120 V · '"I _ == J == __ = J _ == _ =« «105490 7 1) Addition amount is expressed as the amount of chemical in the mass.

2) The amount of oxygen bleaching consists of 2.0% sodium hydroxide and 0.5% magnesium carbonate.

3) The amount of hydrogen peroxide added in bleaching consists of 2.0% hydrogen peroxide and 0.5% sodium hydroxide.

The pulp properties of the laminate staple papers obtained in the Example and comparative examples and the laminate properties of the laminates after the manufacture of the laminates are shown in Table 2 together.

Table 2 10 Mass Properties and Laminate Properties in Example and Comparative Examples

Example 1 Comparison-Comparison ____im. 1 e.g. 2

Mass - Residual chlorine, ppm 50 750 85 property White,% 85.9 88.4 76.2

Alpha-cellulose content, 88.7 85.4 84.5 __% _____

PCB- Heat Resistant, ° C 270 255 250 Feature Electrical resistance, ohm 3 x 10 2 x 10 1 x 10 • · • * t • * • · m • ♦ · # ». . . .

II '. The whiteness and alpha cellulose content were measured according to JIS P-8101] * "*.

Residual chlorine was determined by a colorimetric method of chlorine ions which were soluble in the pulp for 1 hour at 121 ° C.

Air Temperature Resistance Temperature: Indicates the maximum temperature that will not cause blistering when the laminate is heated for 5 minutes with a blower.

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'Insulation resistance after cooking: measured according to JIS C-6481.

As shown in Table 2, the laminate base paper of this invention fulfills the requirements of a high density wiring laminate and has a very significant industrial significance. In addition, it was also shown that without microbial treatment the effect of the invention was not sufficiently utilized.

Claims (9)

An insulation laminate containing a base paper of sulphate pulp impregnated with synthetic resin, characterized in that the sulphate pulp is bleached by a chlorine-free bleaching process, to which a microbial or enzyme treatment is connected, in order to reduce the residual chlorine content of the pulp and dissolve the solids. 10% KOH. 2. Laminate according to claim 1, characterized in that the chlorine-free bleaching process of the sulfate pulp used for the base paper is selected from oxygen-alkali treatment, ozone treatment, hydrogen peroxide treatment and enzyme treatment or a combination of several treatments. 3. Laminate according to claim 1 or 2, characterized in that the sulfate pulp of the base paper has been treated with a lignin-degrading enzyme or a hemicellulose-degrading type enzyme. »· € 4; 4. Laminate according to any of the preceding claims, characterized in that it comprises a plurality of resin-impregnated base paper layers which are bonded together by means of heat and pressure. • · • · Process for the preparation of an insulating laminate, characterized in that the V · sulphate pulp is bleached by a chlorine-free bleaching process, to which a microbial or enzyme treatment is applied, that the base paper is formed from the bleached pulp and that the base paper is obtained. included in the laminate to be produced by hot pressing. A method according to claim 5, characterized in that the base paper is impregnated with synthetic resin and that several resin impregnated base paper layers are stacked on each other and pressed into laminates. ·: .V 30 Base paper containing sulphate pulp intended for an insulating laminate according to any one of claims 1-4, characterized in that the sulphate pulp has been bleached with a chlorine-free bleaching process, to which a microb or enzyme treatment is connected, in order to lower the residual chlorine content of the pulp and the solids content. in 10% KOH, and that the pulp milling rate is at least 450 ml CSF for resin impregnation of the paper. Base paper containing sulfate pulp intended for an insulating laminate according to any one of claims 1-4, characterized in that the sulfate pulp has been bleached by a chlorine-free bleaching process, to which a microbial or enzyme treatment is connected, in order to reduce the residual chlorine content of the pulp and dissolve it in solids. 10% KOH, and that the paper's surface weight is between 80-300 g / m2 and density about 0.4-0.8 g / cm3 for laminate processing of the paper. Use of a base paper containing sulfate pulp bleached with a chlorine-free bleaching process, to which is connected a microbial or enzyme treatment, as part of an insulation laminate forming a printed circuit board. «(• rii <i <• ai 9« <«« · • · · 9 a »· f · t • · · · · · · · · · · · · · · · · · · · · · · · · · I · • · • t · * • I \ • · · • 9 a • · · • · aa • aaaaaa · aaa