JPS58224742A - Manufacture of laminated board - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention produces a laminate by impregnating paper with strong wet strength and good impregnating properties with a water-dispersible resin emulsion and/or resin aqueous solution mainly consisting of a thermosetting resin. It relates to a manufacturing method.

The purpose of this is to improve the flammability, economic efficiency, and
There are no disadvantages related to workability, hygiene, etc.62, and the wet strength of the paper is strong, so there is no paper breakage or significant swelling of the paper during the impregnation process, and there is little warping or twisting as a laminate, and it has good dimensional stability. Furthermore, since it is a water-dispersible resin, it has excellent impregnating properties with paper, and provides a novel method for manufacturing a laminate that has excellent electrical properties, mechanical properties, etc. as a laminate.

Conventional paper-based thermosetting resin laminates include phenolic resin laminates, epoxy resin laminates, melamine resin laminates, polyester resin laminates, diallylphthalate resin laminates, and polybutadiene laminates. The manufacturing method generally involves first dissolving or dispersing resins, various additives, and other necessary materials in an organic solvent that does not contain water or contains no more than a few percent of water, and then This was then impregnated into paper, the solvent was volatilized in a dryer, and the paper was cured by heating and pressure to produce a laminate.

However, in this method, the organic solvent is merely a carrier for applying the resin to the paper, and is discarded after the purpose is achieved, which is not only economically wasteful, but also wastes the organic solvent itself. There were many disadvantages, such as the risk of ignition and the danger of work and hygiene. From this point of view, efforts have been made to change the solvent for resins from organic solvents to water, but the wet strength of paper, which is the base material, was 0.3 KP/15111 in the conventional method.
Since most of the paper has a particle size less than i, when it is immersed in an aqueous resin containing water as the main dispersion medium, the paper swells and dissolves, and the paper breaks and cannot be made into a laminate. In order to increase the wet strength of the paper, various paper strength enhancers have been added to the paper, but this usually results in a decrease in the strength of the paper as a laminate.

The present inventors have discovered that although thermosetting resin laminates have excellent heat resistance, water resistance, chemical resistance, electrical properties, workability, etc., the above-mentioned drawbacks significantly hinder their development. As a result of my research on methods to eliminate the drawbacks of V-16, I have completed the present invention.

In other words, the advantage of the present invention is that it is water-dispersible compared to conventional organic solvent-based solvents, so there is no need to take precautions against fire, and it is non-toxic, so it can be handled with peace of mind in terms of work and hygiene. This is advantageous because it is extremely inexpensive.

Also, compared to conventional organic solvents, water has a better affinity with paper.
Because of its excellent impregnation properties, it is thought that the impregnation properties of the resin dispersed in water are also improved, and for this reason, compared to laminates obtained by conventional methods using organic solvents, the electrical properties, mechanical properties, heat resistance, and water resistance are improved. This is thought to be due to a significant improvement in the properties of the steel, such as hardness and workability.

Another advantage of the present invention is that the paper used as the base material is selected to have good impregnation properties and strong wet strength. It is thought that the good impregnability of the thermosetting water-based resin provides excellent electrical and mechanical properties as a laminate, and the strong wet strength of the paper makes it difficult to impregnate with the resin. It is thought that the distortion caused by the swelling of the fibers is reduced, and therefore the warp and twist of the laminate manufactured by laminating this impregnated paper are reduced, making it possible to create a laminate with excellent dimensional stability. That seems to be the case.

The present invention uses a cellulose paper as a base material having a wet strength of 0.3 to 3.0 KI/15m and a water absorption of 60 to 150fi,'IQmin, and the base material is coated with an organic solvent.
Water containing ~60 wt% is used as a dispersion medium, the charge is cationic, and the viscosity is 10 to 30 polse (10% aq, 25
This method of manufacturing a laminate is characterized by impregnating the laminate with a thermosetting aqueous resin emulsified with an emulsifier mainly consisting of polyacrylamide at a temperature of 1.5 °C, followed by heating and pressing after drying.

Wet strength in the present invention is 0.3 to 3.0KP/15f
Strong i, water absorption 60~160x/10m1n
Large cellulose paper is made of water-soluble materials such as urea formaldehyde resin, polyethylene imine, melamine formaldehyde resin, polyamide polyamine epichlorohydrin resin, and polyacrylamide, which are so-called wet paper strength enhancers, and are crosslinked by heating. This is treated paper that has been treated with a thermosetting resin to improve the wet strength of the paper. The strength of paper is complicated by factors such as the strength and number of the single fibers that make up the paper, the mechanical friction strength due to the entanglement of fibers, the chemical bonding force (hydrogen bonding) that acts between fibers, and the bonding area. The strength of the meat fiber itself is determined by the raw materials used and the type of pulping process, and the mechanical friction strength due to the entanglement of fibers is affected by the beating method and degree and paper-making conditions.

Therefore, wet paper strength agents are involved in improving the chemical bonding force acting between fibers and reinforcing the adhesive area, but rather than improving the strength of paper by this alone, it is due to the synergistic effect of the above factors It is preferable to increase the strength of the paper. The water absorption of paper also depends on the type and placement of the wet paper strength agent, but it is also affected by the type and length of fibers, the composition of hemicellulose and lignin, and the basis weight and specific gravity of the paper. It is preferable to improve by a synergistic effect such as Here, the wet strength is a value measured according to the method of JIS-P-8135, and is 0.3 to 3.0 KF/15 m.
Preferably. o, 36/xsm or less, the moisture in the aqueous resin tends to cause paper breakage, and therefore it is not possible to apply the resin to paper in industrial mass production, and even if it could be applied by some other method. This is thought to be due to the paper being significantly swollen and distorted by the water content of the aqueous resin, but the distortion remains even after it is made into a laminate, resulting in a decrease in dimensional stability. 3. If QKp/15w or higher, the electrical properties, mechanical properties, etc. of the laminate deteriorate, probably due to the large amount of reinforcing agent used to increase paper strength.

Moreover, the water absorption is a value measured by the method of JIS-P-8141, and is preferably 60 to 160 sIll/10m1n. This is thought to be due to poor resin impregnation in the case of 60x/10m1n Sd, but the electrical properties, mechanical properties, etc. are unsatisfactory. 160m/10m
This is thought to be due to significant swelling of the fibers when the thickness is larger than 1.5 in., but the laminate is warped and twisted to a great extent and has poor dimensional stability.

In the present invention, the thermosetting aqueous resin containing 0 to 5 Qwt% of an organic solvent and using water as a dispersion medium is a thermosetting aqueous resin such as phenol resin, epoxy resin, melamine resin, Yulia resin, polyester resin, diallyl phthalate resin, polybutadiene resin, etc. It is a water-based resin that is dispersed in water containing a small amount or no organic solvent. In this case, it is preferable to use only the minimum amount of organic solvent necessary to make the resin water-based and/or improve its impregnating properties into the base material. Features related to workability, hygiene, etc. will be lost. Methods for making resin water-based include emulsifying the resin using emulsifiers such as surfactants and protective colloids (water-soluble polymeric substances), and modifying the resin without using any emulsifier to make the resin itself hydrophobic. There is a method of emulsifying the resin by balancing the properties and hydrophilicity, or a method of making the resin water-soluble from the beginning, such as a resin with low molecular weight, high polarity, and high alkalinity.

In the method of making the resin water-based in the present invention, the charge is cationic and the viscosity is 10 to 30 poise (10% aq, 25
This is a method of emulsifying a resin using an emulsifier mainly composed of polyacrylamide of It exhibits excellent properties that cannot be obtained by other methods.

The polyacrylamide used in the present invention preferably has a cationic charge, and the reason for this may be that it has good compatibility with anionic cellulose paper. This is because it has good impregnation properties and good properties as a laminate.

On the other hand, polyacrylamide with anionic charge is
This may be because it repels the electric charge from the anionic cellulose paper.
Impregnating properties are poor and properties as a laminate cannot be obtained.

The viscosity of polyacrylamide is 10 to 30 in an aqueous solution.
poise (25°C) is preferable, 10 poise
If the emulsifying power is weak, the emulsion stability is poor and uneven impregnation occurs, and the water resistance of the assembled laminate decreases, resulting in significant problems in electrical properties, etc., as well as large variations in mechanical properties, etc. . If it is 30 poise or more, excellent emulsifying power is exhibited, but perhaps because the viscosity becomes significantly large, the penetration and impregnation into the cellulose paper is poor, and various properties as a laminate do not reach the target.

The aqueous resin in the present invention is emulsified with an emulsifier mainly composed of polyacrylamide with a cationic charge and a viscosity of 10 to 30 poise (10% aq, 25°C), but it may also contain other surfactants or It is also possible to use a protective colloid (water-soluble polymeric substance) in combination. These substances are appropriately selected depending on the type of thermosetting resin, the purpose of use of the aqueous resin, etc. Furthermore, if necessary, various water-soluble resins, flame retardants, plasticizers, curing agents, curing accelerators, surface treatment agents, impregnation improvers, etc. can be added and mixed to the aqueous resin.

Laminated boards made by impregnating paper with strong wet strength and good impregnating properties with such thermosetting water-based resins have good electrical and mechanical properties, probably due to the good impregnating properties of the resin into the paper. In addition, due to the strong wet strength of the paper, there is little swelling change in the fibers during coating, and the residual strain is small, resulting in excellent dimensional stability as a laminate, and the use of no or only a small amount of organic solvents. The economic and safety benefits of this are also significant.

The present invention will be explained below using experimental examples.

Experimental example 1゜ In a four-eye flask with a reflux condenser, 20
01. Tung Oil 40II, 37% formalin 250g and cationic with a viscosity of 22poise (10% aq.

After preparing polyacrylamide 1011 (25℃) and stirring to dissolve it uniformly, triethylamine 611 was added.
The reaction was carried out at reflux temperature for 1 hour. Immediately after the reaction was completed, polyoxyethylene nonylphenol ester type nonionic surfactant 11 and diethylaminoethyloleylamide type cationic surfactant 11 were added and stirred to emulsify. The resulting emulsion had good water dispersibility and did not separate even after standing at 20° C. for 15 days.

On the other hand, kraft paper for phenolic resin laminates is treated with polyamide polyamine epichlorohydrin resin and! A treated paper having wet strength and water absorption as shown in Table J1 was obtained. Add 10% of a low molecular weight polymethylolphenol resin aqueous solution to the above emulsion.
This treated paper was immersed in a mixed varnish containing 54% of resin to impregnate it with resin, and dried at 150°C to obtain a B-stage resin content of 54±1.
%, a prepreg with a volatile content of 1.7±0.31 was obtained. Eight sheets of this prepreg were laminated, a copper foil coated with a 35 μm thick adhesive was layered on one side, and heated and pressed at 170° C. for 90 minutes in a press to obtain a copper-clad laminate with a thickness of 1.6 fjl. The properties of this laminate are shown in Table 1.

Experimental Example 2゜Phenol 140 was added to the same reaction apparatus as in Experimental Example 1.
Ii, tung oil 50Jl + and 85 thiphosphoric acid II, 1
After reacting at 30°C for 3 hours, it was cooled, then 150 Jl of 37% formalin and 89% aqueous ammonia were added, and after reacting at 90°C for 3 hours, it was dehydrated under reduced pressure to bring the water content in the resin to 15%. . The resin obtained in this way is methanol/
It is soluble in a mixed solvent of toluene = 1/1, but insoluble in water.

Next, 125 g of a 10% aqueous solution of polyacrylamide having the electric charge and viscosity shown in Table 1 and 12! The above resin liquid was combined with M and stirred to emulsify.

On the other hand, 7) Paper for phenolic resin laminates is treated with polyamide polyamine epichlorohydrin resin, and the wet strength is 0.
．． A treated paper with a water absorption of 75 KP/15 ml and a water absorption of 95 m/10 ml was obtained. This treated paper was immersed in a mixed varnish of the emulsion and a low molecular weight polymethylol resin aqueous solution in the same manner as in Experimental Example 1, dried, and pressed to obtain a copper-clad laminate. The properties of this laminate are shown in Table 1.

Experimental example 3゜Ebiko) 1001 (epoxy resin manufactured by Shell Chemical Co., Ltd.)'
5oII, Epicote $828 (epoxy resin manufactured by Shell Chemical Co., Ltd.) 2ON, dianediamide [1, penzyldimethylamine 0.31. Mix 20I of acetone,
After forming a uniform dispersion, a polyoxyethylene nonylphenol ester nonionic surfactant IJF and a cationic viscosity of 21 poise (10% aq, 25°C) were added.
) of polyacrylic and amide 30JI were added, stirred and emulsified, and further 12 (l) of water was added for dilution.

Hereinafter, the same treated paper used in Experimental Example 2 was immersed in a mixed varnish prepared by adding a low molecular weight polymethylol phenol resin aqueous solution to the emulsion in the same manner as in Experimental Example 1, dried and pressed to form a copper-clad laminate. Got the board. The properties of this laminate are shown in Table 1.

On the other hand, in Experimental Example 3, methyl cellosolve 4 was used instead of water.
A copper-clad laminate was obtained in exactly the same manner as in Experimental Example 3, except that 80 g of 0Ii and methyl ether ketone were used to form a solution. The properties of this laminate are shown in Table 1.

As shown in Table 1, laminate A 2.5.8.9 was made using treated paper of the present invention with a water absorption of 60 to 160 wes710 m1n and a wet strength of 0.3 to 3.0 and P/15 m. This is thought to improve the impregnability of the thermosetting water-based resin, and for this reason, it has excellent electrical and mechanical properties as a laminate, and the paper has strong wet strength, so it not only does not break. It is thought that the distortion caused by swelling of the fibers due to water in the aqueous resin during resin impregnation work will be reduced.
This seems to be the reason why the laminate has excellent dimensional stability with little warping or twisting. In addition, these laminates have a cationic charge according to the present invention and a viscosity of 10 to 30
Poise (10% aq, 25°C) polyacrylamide as the main component is used as an emulsifier, so it is thought that the emulsion stability of the thermosetting water-based resin is excellent and the compatibility with paper is excellent. It is thought that this allows the resin to penetrate deeply and uniformly, resulting in excellent electrical and mechanical properties as a laminate.

Laminated board A61 is thought to be distorted by mechanical stress during the resin coating and impregnation process due to the weak wet strength of the paper, and as a result, the laminate board warps and twists, reducing dimensional stability. It seems that it was done.

Laminated board rot 3 is thought to have had a large amount of paper strength enhancer added to strengthen the paper's wet strength, which weakened the original properties of the phenolic resin. This seems to be due to a decrease in physical and mechanical properties.

It is thought that the laminate shoulder 4 has a low water absorption and thus has low impregnability with the aqueous resin, and for this reason, the electrical and mechanical properties of the laminate are considered to be low.

Because the laminate A66 had too high water absorption, the water in the aqueous resin caused significant swelling of the paper fibers, and this distortion is thought to have caused the laminate to warp and twist, which led to a decrease in dimensional stability. It seems to be.

It is thought that the laminate shoulder 7 is because the viscosity of the emulsifier is too low and the emulsifying power is too weak, so the emulsion stability of the water-based resin using this is also poor, and therefore it is applied unevenly to the paper. It is thought that uneven impregnation occurred in the laminate, which caused variations in performance as a laminate and made it unusable.

It is thought that the viscosity of the emulsifier in the laminate with %10 is too high, which deteriorates the compatibility and stain resistance of the aqueous resin used with the paper, resulting in poor impregnation and poor performance as a laminate. seems to have decreased.

Laminate shoulders 11 and 12 are considered to be because the charge of the emulsifier is anionic, so the water-based resin using this is not compatible with the anionic paper fibers, so impregnation is poor and the properties of the laminate are poor. seems to have decreased.

Laminated board/%13 and 14 compare the case where water was used as the resin dispersion medium and the case where an organic solvent was used.Since water has better impregnating properties with paper, it was used as a laminate board. It is thought that water-based resins are superior to other resins, and are thought to have superior not only electrical and mechanical properties, but also punching workability and dimensional stability. Furthermore, compared to organic solvents, water is superior in that it is not flammable, is economically cheap, and is safe in terms of work and hygiene.

Claims (1)

[Claims] Wet strength is 0.3-3.0KP715m, water absorption is 6
The base material is cellulose paper having the characteristics of 0 to 1601 @ 710 m1n, the dispersion medium is water containing 0 to 60 wt% of an organic solvent, the charge is cationic, and the viscosity is Ig to 3Qpolse ( A method for manufacturing a laminate, which comprises impregnating the laminate with a thermosetting aqueous resin emulsified with an emulsifier mainly composed of polyacrylamide (10% aq, 25°C), drying, then heating and pressurizing.