JPS63257633A - Manufacture of laminated product from inorganic paper - 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 (Industrial Application Field) The present invention relates to resin-impregnated synthetic inorganic paper products based on natural or synthetic sheet silicate crystals, and more particularly, to a resin-impregnated synthetic inorganic paper product that is useful for applications such as printed circuit boards. The present invention relates to laminates formed from impregnated papers of this type. Laminates according to the invention serve as substrates for printed circuit assemblies with chip carriers and other components provided or printed on the substrate. The substrate also provides electrically conductive connections through a reducing or adding circuit construction process.

(Prior Art and Its Problems) To date, considerable efforts have been expended in the development of papers based on inorganic materials. Bulletin 647
(1969)) by the Bureau of Mines as “Fluorine Mica”
Natural and synthetic micas have been explored for quite some time, as reported in . In particular, it is described on pages 214-242 of said publication.

Synthetic paper made from vermiculite ore! A-building is described in US Pat. No. 3,434,917.

U.S. Patent Nos. 3,325,340 and 3,356,
No. 611 describes the preparation of vermiculite suspensions useful for the preparation of fibers or coatings.

Although various inorganic papers have been produced commercially, large-scale applications in electronic circuit boards have not yet been developed. Rather, the papers and boards currently used for electrical purposes, such as component insulation, transformer packaging, and circuit boards, are predominantly organic containing fiber fillers and/or fabric reinforcements. Sintered ceramics such as alumina are commonly used when high temperature substrates are required.

U.S. Pat. No. 4,239,519 discloses an overlapping ion-exchanged micas prepared from synthetic lithium- and/or sodium-containing water-swollen mica in which the lithium and/or sodium ions of the mica are partially exchanged with larger cations. A mica paper based on platelets is disclosed. Constructing a circuit board from such paper is
It is disclosed in European patent application EP 0115399.

According to E P O 115 399@, laminated mica circuit boards are manufactured by a method in which paper is first impregnated with an organic resin. The preferred resin is at least 15% by weight of the composition.
This is the epoxy that makes up the epoxy. A denominator of up to about 75% resin is used in a particular monolayer, with a range of 20-50% being preferred. Preferably, the paper consists of synthetic lithium fluorohectolite mica with lithium ions partially replaced with potassium ions, the potassium-substituted fluorohectolite being flocculated in an aqueous medium that can be processed into paper by conventional methods. form a square.

The board is made from impregnated mica paper by stacking multiple layers of paper and then heat pressing to compress the paper into a unitary V4 layer. A 60 mil thick standard board has a thickness of 10 to 1 depending on the paper thickness.
Generally formed from five sheets of paper. The board is 65x10"7/
"Characterized by the low coefficient of thermal expansion of C, 65-80x 10"
/”C is preferred.

The laminate produced according to EP 0115399 is particularly suitable for use in printed circuit assemblies.

The plate may include one or more chimp carriers or other electrical components provided on its surface. Furthermore, conductive circuit components are used by adding or subtracting techniques. In addition, synthetic mica paper is sometimes laminated with glass fabric to strengthen and improve the adhesion of circuit components. This type of thin layer is sufficiently flexible for use as a flexible circuit board.

Natural mica has also been used to make laminates. For further discussion of the use of naturally occurring materials to manufacture paper products, see E.G. Dingman, Society of Plastics Engineers Journal (September 1961), pp. 981-983. can do. This publication describes mica papers made from reconstituted or incorporated natural mica and the use of this type of paper with resins to produce laminates.

A particular advantage of circuit boards produced according to EP 0115399 from synthetic water-swollen mica is the thermal expansion properties of boards or substrates produced by laminating resin-impregnated papers made of such crystals. The coefficient of thermal expansion of such laminates is isotropic in a planar sense, ie in the plane of the circuit board.

That is, the coefficients of thermal expansion are particularly equal along the X and Y axes.

This is in contrast to most 1a laminates or substrates currently used in electrical devices, where the coefficient of thermal expansion along one planar axis tends to be sometimes twice as large as the coefficient of thermal expansion along the other planar axis. There is a marked contrast.

Critical testing of the suitability of laminates for use in the construction of electrical circuits tests the laminate's ability to withstand the treatments involved in adding electrical circuit components. Applications of conductive circuitry include subtractive or additive techniques such as chemical electrodeposition, electroless/contact deposition, printing, chemical etching, physical pressing, vacuum deposition, or vacuum sputtering. The circuit components are plated or included in holes in the board or reside on the board surface embedded within the multilayer circuit board. Independent circuit components or circuit components of packaged integrated circuit components include the application of high temperature flux and wave soldering processes.

The cycles of chemical solutions and heat applied to the laminated mica during such processing particularly require the board material to be moisture resistant and resistant to microcracking and/or delamination which renders the surface exposed to the action of moisture. . An important factor influencing moisture resistance is the chemistry of the inorganic mica or other crystals used to make the paper, as well as the extent to which the paper is successfully impregnated with resin.

The moisture resistance of laminated products made from inorganic crystals can be evaluated by exposing the material to moisture at elevated temperatures, for example by immersion in boiling water. It is preferred that the laminate product exhibit little or no water uptake and therefore exhibit no appreciable reduction in dielectric strength, loss tangent, and dielectric constant as a result of water action.

In the prior art, 11-layer products consist of paper made from suitably synthetic water-swellable lithium- and/or sodium-containing mica crystals; Desirable high aspect ratio,
Synthetic lithium-containing water-swellable mica crystals were obtained in terms of excellent agglomerate properties in aqueous media and acceptable electrical properties in laminate formation. Of course, efforts continue to further improve the electrical properties of these preferred lithium-containing materials, with processing improvements such as the use of complex ionic flocculants, and treatment of paper sheets after formation to increase moisture resistance. , resulting in a substantial improvement in the performance of these laminated products to withstand electrical damage in the presence of moisture.

However, laminate products require superior electrical properties than those produced using prior art techniques. Accordingly, a primary object of the present invention is to provide a laminated product formed from a strong paper and a laminated resin that has improved moisture resistance and retains electrical properties when processed in high humidity conditions.

Furthermore, it is an object of the present invention to provide an improved paper manufacturing process by which inorganic papers can be made from sheet silicate crystals, whether natural or synthetic, which exhibit improved stability to hydration.

SUMMARY OF THE INVENTION The present invention provides laminate products made from synthetic or naturally occurring water-swollen sheet silicate materials that are substantially lithium-free. These materials contain aluminosilicate crystals in sheet-like form, with exchangeable intermediate cations selected from sodium, hydrogen, calcium and magnesium. These materials are either synthesized or selected from available naturally occurring lithium-free sheet silicates.

The production of a laminate product according to the present invention involves first forming a gel containing lithium-free sodium, hydrogen, magnesium and/or calcium containing sheet silicate crystals and agglomerating the gel to form crystals to form agglomerates. The process consists of forming a paper sheet from the agglomerate, drying, and impregnating the resulting paper with a suitable laminating resin, such as an epoxy resin. The impregnated paper is then laminated and fused to the board product using heat and pressure. The obtained plate is similar to the prior art V
When compared to four-layer lithium-containing board products, it exhibits significantly improved moisture resistance and retention of electrical properties.

If desired, conventional flocculants can be used to prepare the required paper sheets from the sheet silicate gels as described above. However, it is preferred that the flocculation is carried out in the presence of an ion exchange conditioning agent which improves the susceptibility of the resulting paper to resin impregnation and thus improves the moisture resistance of the final product. More particularly, it has been found that the use of an octylamine conditioning agent during the aggregation process provides a paper with substantially improved lamination properties. The octylamine conditioning agent is believed to ion-exchange with sodium and other exchangeable ions present in the aggregate, resulting in
It is more compatible with organic laminating resins than standard paper and therefore, when incorporated into laminated products, results in a paper with substantially improved lamination performance and water resistance.

In the prior art, for example, European application EPO 11539
As described in Japanese Patent No.
The paper is impregnated with an inorganic resin such as an epoxy resin, the impregnated papers are stacked to form a board precursor, and finally the precursor is heated and pressed to produce an integral board.
A laminate product can be obtained. Although sodium-lithium mixed papers are used in the manufacture of such board products, the preferred paper was lithium fluorohectolite paper made by the method described in US Pat. No. 4,239,519@.

The board products produced by the above method showed good physical and electrical properties, but the electrical properties deteriorated a little when exposed to moisture at high temperatures. Thus, for example, a board product containing lithium fluorohectolite paper and consisting of an 84 layer resin of epoxy with a loading of 45-50% by weight has a dielectric constant of at least 4.5 and a dielectric constant of about 0.0
Having a loss tangent not exceeding 30, a water absorption rate not exceeding about 0.6% by weight, and an insulation resistance greater than 108 ohms, such products, when placed in boiling water for 2 hours, have a loss of 1.7% by weight.
of water increased, the loss tangent in such cases increased to 2.4 or more, and the dielectric constant decreased to 2.9. It is therefore desirable to further improve resistance to shifts in electrical properties due to moisture.

The use of natural or synthetic lithium-free sheet silicate crystals can significantly improve the electrical performance of laminate products against the effects of moisture. Among the lithium-free materials that can be used for this purpose, the sheet silicates are selected from lithium-free vermiculites, sodium fluorohectolites, and sodium fluoromontmorillionoids in suitable crystalline forms. The last sodium montmorillionoid material is particularly suitable for the production of laminates and is produced by controlling the crystallization of sodium magnesium aluminosilicate containing high analytical levels of fluorine. A typical glass composition suitable for the synthesis of crystalline glasses for this purpose is approximately 50-62% SiO
□, 20-28% MillO 15-15% NazO
, and 8-13% (as analyzed) of fluorine. The preparation of these glasses and paper-making gels does not form part of the present invention, but is disclosed in the patent-pending "Sodium Fluoromica Glass-Ceramic" (Japanese Patent Application No. 61-29029).
No. 4).

Paper making gels consisting of vermiculite, magnesium and aluminum containing crystalline sheet silicate materials are known. Interlayer cations in vermiculite include hydrogen, calcium, magnesium, and/or sodium, with small amounts of iron, nickel, or the like present in the crystal composition. Such gels can be used in the preparation of said moisture-resistant laminate products that are substantially lithium-free.

U.S. Patent Nos. 3,325,340 and 3,356,611
No. 3,434,917 describes vermiculite suspensions and their conversion into paper. However, a preferred gel for making vermiculite paper is disclosed in U.S. Pat.
It is described in ``Glue, Gel Products, and Gel Manufacturing Method'' filed in No. 954 (Japanese Patent Application No. 61-134731). These consist of vermiculite crystals foamed with a -grade aminocamboxylic acid and dispersed in an aqueous solution (described in more detail below); a typical blowing agent is β-
It is alanine.

Gel-containing foamed vermiculite or sodium montmorillionoid can be used directly to make paper, but glass m#t can also be used to improve the strength and bonding properties of paper sheets.
It is more preferable to add. The addition of such lli fibers is typically added to the gel used to make the paper.
Consisting of a solids content of 50% by weight.

To make paper sheets from gels as described above, a flocculant is added to flocculate the gels. Addition of relatively large inorganic monovalent cations, such as potassium, to the gel can promote flocculation, or other large organic or polycations can be used.

The resulting agglomerate is preferably comprised of a suitable glass fiber adduct and can be easily formed into paper by handsheet or continuous paper manufacturing processes.

Methods for manufacturing board products from inorganic gels have been standardized in the prior art and can be easily adapted to the production of lithium-free board products. A suitable method is to first prepare a gel of the selected lithium-free sheet silicate material, add the gel to water with glass vanes dispersed in deionized water, and add a flocculant to the mixture to form sheet silicate crystals. to create a slurry. The resulting slurry is then rolled into a handsheet mold, drained, and dried to form a paper sheet.

To make laminates from paper sheets made in this way, they are generally first pretreated with a waterproofing agent, typically a water-soluble compound such as guanidine H(l) to impart water resistance. The board is impregnated with an epoxy resin containing a hardening agent, pre-cured before lamination (B stage), stacked in multiple layers, preformed to a specified thickness, and finally laminated under heat and pressure to produce a cured board product. Manufacture. Using such standardized methods,
Electrical properties and resistance to moisture degradation can be readily compared between conventional board products prepared from lithium fluorohectolite gels and board products from sodium montmorillionoid gels prepared according to the present invention. Example 1 summarizes the results of such comparisons.

(Example) Example 1 Two types of gel samples with different compositions were blended as starting materials,
An inorganic paper sheet was prepared. The first gel containing synthetic sodium fluoromontmorylionoid crystals weighed 57
．． 5% s iOz , 25.0% M2O, 6.8%
A glass-ceramic sample based on NazO, and 10.7% (analyzed) F was dissolved in deionized water.
; Manufactured in solution. Another gel was formed by dissolving a lithium fluorohectolite glass-ceramic sample in water, where the glass-ceramic was approximately 64.5% 5i0 by weight.
2.17°3% M! It is formed from a glass based on 10.8.0% LtzO and 10.2% (as analyzed) fluorine.

To make paper sheets from these silicate gels, glass fibers and gels are combined in an aqueous medium adjusted to pH 2.5 using aqueous sulfuric acid. The proportions of the combination to give an a-fiber-containing gel with a solids content of about 10% by weight are: 20% glass 41% solids;
The remaining 80% is silicate crystals. A small amount of 0.2% polyethyleneimine solution is added to each of the two types of fiber-containing gels to cause flocculation. The polyethyleneimine is preferably available commercially as Epomin SP-012 flocculant from Aceto Chemical Company of Flushing, New York. After agglomeration, the resulting slurry was poured into a handsheet paper forming tool, drained and formed into paper sheets, absorbed and dried, and finally dried at 80°O in a chrome-plated dryer at 80°C. let

After the paper sheet is prepared, it is pretreated by soaking the paper in a 1.0 M guanidine HC reaction solution for 30 minutes. This treatment reduces the paper's susceptibility to hydration in the presence of ambient moisture. Wash the guanidine-treated sheet repeatedly with clean deionized water and
Thoroughly dry for at least 2 hours at 110° C. for further processing.

To impregnate the paper sheet produced as described above with resin, the sheet is immersed in a 1-boxy resin varnish for a sufficient period of time to completely saturate the paper with the resin.

The epoxy resin, commercially available as DER-566 from The Dow Chemical Company, is 13.5 PHR (parts per 100 parts resin) of diaminodiphenylsulfone (DDS).
> and 0.7 PHR of boron trifluoride monoethylamine (BF3) is added to an acetone vehicle containing as a curing agent.

Add enough resin to the solvent to give about 45% solids content in the varnish. Other known laminating resins for fiberglass lamination can be used instead, including phenolic polyester, polyimide and polyetherimide resins.

The sheets of lithium- and sodium-containing paper are immersed in this resin varnish for about 15 minutes, then removed, air-dried for 10 minutes, and finally precured in a forced draft oven at 160° C. for 4 minutes. The precured paper was then vacuum dried overnight and
Store in desiccator until use.

To make a laminate product from the resin-treated paper thus obtained, approximately 10 sheets of treated paper are stacked v4, each to form a laminate structure, and the facing Teflon fluorocarbon end sheets are placed in the opposite direction of the laminate. Attach the matching surfaces and place the assembly on a laminating carvel press. Each assembly was pressed at room temperature to yield 24.6 Ny/cd
(350 psi) pressure is applied.

Next, the temperature was increased to 125°C at a rate of 10°C/min, and the pressure was increased to 49°C.
．． 2h/caf <700psi);
The temperature is further increased to 200°C, and then the temperature and pressure are maintained for 2 hours. After completing this lamination step, the resulting laminate was cooled under pressure to below 80° C., the press was removed, and the laminate was trimmed to remove any oozing resin.

The resin content of the laminate products made from each of the two synthetic papers mentioned above is about 40% by weight.

The laminate made from the above-mentioned lithium fluorhectorite paper was immersed in boiling water for 2 hours and its moisture resistance was evaluated.The water absorption rate was as high as 1.7%, and the loss tangent after treatment was as high as 1.7%. exceeded 0°3 (100H2>) and the dielectric constant decreased to below 2.9.On the contrary, the laminate product containing the sodium fluoromontmorillionoid crystals produced as described above had a high ability to absorb boiling water. The dielectric constant was 0.6% by weight, the dielectric constant after treatment was about 6.93, and the loss tangent was about 0.224.

In an effort to stabilize such electrical properties, modifications to the process used to make the laminate product according to Example 1 above have been developed to improve moisture resistance and physical integrity. Ta. For example, synthetic mica paper is treated with chemical coupling agents such as 6-aminocaproic acid and beta-alanine to harden the paper into a board, as described in "Laminated Synthetic Mica Products" by E.R. Fretz et al. The coupling of the paper to the LA layer resin used for this purpose can be enhanced. However, recent data show that even with such paper treatments, board products made from lithium-free paper according to the present invention are superior to paper treated for comparison containing lithium fluorohectolite crystals. Exhibits better moisture resistance than board products made from.

Table ■ below shows that sodium fluoromontomorillionoid and lithium fluorohectolite papers were tested at β prior to compounding into a laminate product using the method described in Example 1.
-alanine (ALA) or 6-aminocaprone M (
The experimental results obtained when pre-treatment with ACA>coupling agent are shown. Table I shows the weight of the dry plate after 2 hours of boiling treatment in weight percent for each pretreatment of each laminate of two compositions and of two types of paper [(ACA and ALA)]. The loss tangent and dielectric constant for each product measured at 1 ooHz after boiling water treatment are shown.

1--Yu paper type Cup HzO dielectric constant Loss length λU
Increase (%) ■ Na Fluo zvA CA O,225,30,0
31 Montmorillionoid Li Fluor ACA 1.2 6.0 0
．． 106 hectorite Na fluoride ALA O,445,360
,019 Montmorillionoid Li Fluor ALA 0.96 5.87
0.099 hectorite The above data shows that laminated products based on sodium fluoromontomorillionide improve their electrical properties after exposure to a severe humid atmosphere when compared to products based on lithium fluorohectorite. It shows that it is generally superior in terms of retention. The former products therefore constitute the preferred materials for the preparation of the laminates according to the invention.

Although excellent results are generally obtained using paper based on sodium fluoromonomyliolionoid, alternative lithium-free materials, especially magnesium-based naturally occurring vermiculite, are less durable. It can be used as an alternative crystal source for the manufacture of certain electrical circuit board products.

Example 2 below shows a method for making such a product.

Example 2 Vermiculite gel was made by dispersing South African vermiculite in an aqueous 3M β-alanine solution under constant suspension.
It is prepared by forming a vermiculite gel consisting of 10% by weight vermiculite solids. The first vermiculite used is screened to remove particles with a particle size of 270 mesh or more. The dispersed vermiculite formed a gel and was then centrifuged at 8000 rpm for 3 hours.
A supernatant containing β-alanine is separated from the laminated vermiculite particles. Decant the liquid and wash the vermiculite product repeatedly with deionized water.

The washed laminated vermiculite thus obtained is slurried with distilled water in a blender to form a vermiculite suspension. The vermiculite suspension was then added to the aqueous suspension of glass fibers at a rate of 4 parts vermiculite solids for 1111 parts of each glass II, giving a total solids content of about 9.7% to form a paper Prepare production slurry. Add 10% aqueous sulfuric acid to maintain the - of the slurry at about 2.5. Next, a cation II agent commercially available as Riteen 210 flocculant, Praue State,
The slurry is agglomerated by the addition of a small amount of a 0.1% aqueous solution of an acrylamide-based copolymer commercially available from Vercules, Wilmingdon. The resulting agglomerate is sent to a handsheet paper machine, drained and finally dried to produce vermiculite paper sheets.

A laminate product is produced from this paper by the method described in Example 1. First, the paper is treated with a guanidine hydrochloride solution and dried. This is then impregnated with epoxy resin varnish and precured. Finally, they are stacked to form a laminate and cured under heat and pressure to form a laminate product having a thickness of approximately 26 mils and a resin content of 38.5% by weight.

The laminate made from vermiculite as described above exhibits a dielectric constant of 4.28 and a loss tangent of 0.019 after being soaked in water for 24 hours at room temperature. Although these properties indicate that the vermiculite laminate exhibits better electrical properties than the lithium fluorohectolite product after a 2-hour boiling test, these properties are higher than the relatively higher values exhibited by the vermiculite laminate. Due to the water absorption rate, it cannot be compared with products based on sodium fluoromontmorillionoid.

Although the use of lithium-free sheet silicate materials in the manufacture of laminate products can considerably improve the retention of electrical properties under the influence of moisture, further improvements in the properties of the plates, particularly the physical integrity of the plates, are desirable.

For example, in a laminate product made as described in Example 1 from a sodium fluoromontomorillionoid species, microscopic voids or cracks can be detected by microscopic examination of a cross-section of the laminate product; at least in part
The laminated resin completely impregnates the synthetic paper material, causing failure.

FIG. 1 is an electron micrograph showing a polished cross-section of an epoxy resin-impregnated plate product manufactured using the method of Example 1 at a magnification of 200 times. Microcracks in this type of board product occur parallel and adjacent to the paper sheet silicate crystals that line up in the plane of the paper and appear on the microscope as a pattern of bright wavy vertical parallel lines. A pattern of small circles or bright spots is formed by the cut end surface of the paper glass 4M fibers.

Several relatively large cracks in the board are observed under the microscope as black vertical cracks with colored edges in scattered locations.

Another drawback associated with the manufacture of board products using the above method is the need to treat the paper in guanidine salt M salt or other waterproofing organic solutions to increase moisture resistance. Therefore, a process that does not require a separate paper treatment step to increase moisture resistance or resin-paper compatibility is desirable.

In the prior art, attempts have been made to produce synthetic papers with enhanced water resistance through the use of specific flocculants or chemical agents added during flocculation to impart hydrophobicity to the resulting paper.

For example, U.S. Pat. No. 4,454,237 describes the use of silane coupling agents as flocculants to produce paper that reduces moisture absorption under humid conditions, and U.S. Pat. No. 4,455. No. 382 describes the use of complex polyelectrolyte flocculants to achieve similar results.

The use of octylamine conditioning agents in combination with known flocculants such as those described in the prior art substantially improves the lamination properties of paper when used with epoxies or similar lamination resins for making composite board products. I found something that could be improved. The use of octylamine additives generally results in laminate products that are substantially free of cracks and voids, and there is no need to treat the paper for water resistance prior to incorporation into the laminate product.

In order to compare the effects of the agglomeration treatment on the properties of the laminated products, a series of papers made from sodium fluoromontmorillionoid gels as described in Example 1 were prepared, except that they were agglomerated with additive solutions of different compositions. epoxy-impregnated laminates were manufactured. The method used and the properties of the resulting laminate product are described in the following examples.

Examples 3-8 Sodium fluoromontmorillionoid paper is prepared by the handsheet method using standard methods. A batch of paper making slurry was prepared by adding 0.7 grams of Glass III (6,35rRrr,
1/4 inch long) by first dispersing them.

The state is prepared by adding 10% aqueous sulfuric acid. To obtain a papermaking gel from this suspension, 2.8 grams of sodium fluoromontmorillionoid crystals (dry) are added to the fiber suspension with stirring.

A selected one of the group of flocculant solutions was then added to the sodium fluoromontmorillionoid suspensions to flocculate, and each flocculated suspension was then injected into a handsheet paper forming machine. , drained, dried under pressure between blotter papers, and then further dried in a chrome-plated dryer at 80°C.

The flocculants used to produce various papers are selected from quaternary ammonium salts, primary and secondary amine complexes, and amine silanes. An aqueous solution of octylamine is also prepared for addition to the gel as a conditioner. Standard solutions of these additives are made by WfA for use in studies such as those shown in Table 1 below. Four types of gel additives are reported, and the active ingredients of each additive and the composition of each additive solution are indicated.

Table ■ Gel additive Active compound Solution composition type Quaternary ammocetyltrimethyl 10% aqueous nium salt Ammonium bromide CTM
A (cTMA) 1st/2nd polyethylene 0.2%
Aqueous polyamine imine (PEI) Epoxy 5P-012 aminosilane N-β-aminoethyl 2% aqueous aminopropyl Z-60
20, or trimethoxysilane 20% aqueous (Z6020 silane) Z -6020 (pH
7,8) Octylamine Octylamine
10% Aqueous (OCA > Octylamine HC9J < pH 8) Using the additives described above, a series of six types of papers are prepared from sodium fluoromontmorillionoid gels by the method described above. When preparing these papers, the flocculation time, flocculation size, clarity of supernatant water from the handsheet former, wetness of the formed paper, sheet wet strength, and final paper sheet weight were recorded.

The table ■ below shows that the gel additives listed in the above table ■
Seed agglomeration treatment is performed and paper formation results for each are shown. Table 1 identifies the additive solution or solutions used, the general paper forming properties of each agglomerated suspension, and the wet strength and sheet weight of the resulting paper. In all cases, flocculation of the suspension is essentially instantaneous, with flocculation dimensions ranging from medium to large, and white water generated during sheet formation ranging in clarity from cloudy, slightly cloudy to clear. .

Table ■ Suuken Flocculant Sheet formation Wet strength Sheet type car 3 1.5- Fairly good Good
2.95 'j10% CTMA 410dlO% Good Fairly good 2,
9g octylamine + 2.5d 0.2% PEI 51d20% Fairly good Good 3.0
gz6020+ 2.5d 002% PEL 6 0.5d2% Fairly good Good
3.2gZ6020+ 2.5d 10% CTMA 7 2572% Good Fairly good
2.7g6i, gio% Good Good
2.6g CTMA + 2.5d 0.2% EI To prepare board products from the paper sheets produced as described above, 15.24 x 15.24 cm (6X 6 inch) sheets of various papers were subjected to the impregnation and the Epoxy impregnation with the resin varnish described in Example 1 using the processing method. No pretreatment of the paper with guanidine FA salts or other agents is employed. During pre-curing of the impregnated paper, severe blistering in the paper of Example 3 and slight blistering in the paper of Example 4 in Table 1 above are observed.

However, none of the papers blister during the board v4 rolling process.

To form a laminate product from the epoxy-impregnated paper thus obtained, 13 sheets of each type of impregnated paper were stacked to form a laminate, each 6 laminate was stacked using the lamination method described in Example 1. Heat and pressurize to compress. The resulting laminate products are then evaluated for retention of electrical properties when exposed to moisture and freedom from physical cracks and voids by scanning electron microscopy testing.

The results of the board evaluation for each of the six examples shown in Tables ■ and ■ above are shown in Table ■ below. For each of the plates produced as described above, Table 1 shows the resin content of the plate, the weight percent, the thickness of the plate in mils, and the appearance of the plate in amplified cross-section by scanning electron microscopy. The appearance of the cross section of each plate is
E), Good < G), Fairly Good (F), or Poor (P), each evaluated for defects such as cracks and voids. Excellent appearance indicates that no cracks or voids are observed; The appearance shows that considerable creases and many voids are observed in the laminated product.

Table ① also shows that for each laminate, the distance from the board after direct lamination to the board surface during the board lamination process is 6.35 r.
The required copper peel strength or strength in Ky (bond) is the average absorption rate (Hz O Absorption amount) and electrical properties of the plate sample after water treatment are determined by dielectric constant (D, C).

), loss tangent (L, T, ) and insulation resistance (1°R,)
is expressed in ohms.

Table ■ SEM @ Peel strength 1 min Coagulant Resin content Box cracks/voids Acid dielectric: 3 CTMA
52.1% 41 mil E/G O, 273 (
0,6) 4 Octylamine 52.2% 45mil E
/ E 0.54/PE I
(1,2>5 260
20/PE I 42% 36mil P/P
O,18<0.4) 6 6 26020/CTMA 51.5% 31 mil E/G O,327(0,7) 7 26020 39% 28 mil
E/P O,18(0,4) 8 CTMA/PEI 51.2% 43 mil
E/E O,18<0.4> Table ■(Conclusion) CTMA O,195,380,3203
,9x106 octylamine 0.18 5.0
4 0.050 1.4x108/PEI 26020/PEI O,4411,580,
2102,1x10'26020/CTMA O,4
4,720,0211,4x101126020
0.45 12.99 0.258
6.0xlO'CTMA/PEI O,2
75,880,0495,6x105 (Effects of the Invention) From the above data, it appears that the use of octylamine as a conditioner in conjunction with known flocculants, especially polyelectrolyte amine compounds such as polyethyleneimine, improves lamination bonding (cracking and void type). freedom from defects) and good retention of electrical properties after exposure to water. Therefore, the use of an octylamine conditioner during gel aggregation constitutes a particularly preferred means of producing high quality lithium-free laminate products according to the present invention.

Claims (1)

Claims: 1) (a) preparing gel-containing crystals of naturally occurring or synthetic water-swollen sheet silicate material free of lithium; (b) coagulating the gel such that the silicate material forms a cohesive mass; (c) forming the agglomerated mass into a lithium-free inorganic paper sheet; (d) impregnating the paper sheet with an inorganic laminated resin to form a resin-impregnated sheet; (e) forming two or more resin-impregnated sheets; a synthetic or natural product comprising the steps of stacking impregnated paper sheets into a laminated preform and (f) heating the preform under pressure at a temperature and time sufficient to fuse the sheets into a laminated product. A method for producing a laminated product consisting of a plurality of fused sheets of inorganic paper made of sheet silicate crystals impregnated with a laminated resin. 2) The method of claim 1, wherein the lithium-free sheet silicate material comprises exchangeable interlayer cations selected from the group consisting of sodium, hydrogen, calcium and magnesium. 3) The method according to claim 1, wherein the sheet silicate crystal is a synthetic sodium montmorillionoid crystal. 4) The method according to claim 1, wherein the sheet silicate crystal is a vermiculite crystal. 5) (a) preparing gel-containing crystals of naturally occurring or synthetic water-swollen sheet silicate material free of lithium; (b) preparing the gel in the presence of an octylamine conditioning agent such that the silicate material forms a cohesive mass; (c) forming the agglomerated mass into a lithium-free inorganic paper sheet; (d) impregnating the paper sheet with an inorganic laminated resin to form a resin-impregnated sheet; (e) two or three (f) heating the preform under pressure at a temperature and time sufficient to fuse the sheets into a laminated product; Alternatively, a method for producing a laminated product comprising a plurality of fused sheets of inorganic paper made of naturally produced sheet silicate crystals impregnated with a laminated resin. 6) The method of claim 5, wherein the lithium-free sheet silicate material comprises exchangeable interlayer cations selected from the group consisting of sodium, hydrogen, calcium and magnesium. 7) The method according to claim 5, wherein the sheet silicate crystal is a synthetic sodium montmorillionoid crystal. 8) The method according to claim 5, wherein the sheet silicate crystal is a vermiculite crystal. 9) The method according to claim 7, wherein gel aggregation is induced by adding a polyethyleneimine flocculant. 10) The method according to claim 9, wherein the organic laminated resin contains an epoxy resin.