JPH0321337B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a so-called cold punching (low-temperature punching) type cellulose-based halogen-containing unsaturated polyester resin flame-retardant metal foil-clad electrical laminate which has excellent moisture resistance and improved punching workability. The metal foil-clad electrical laminate used in the present invention refers to a metal foil-clad laminate used, for example, as a substrate for various electronic components. means. The above laminate is manufactured by impregnating a cellulose base material with an unsaturated polyester resin, then laminating and curing the impregnated cellulose base material. For example, the present inventors have already proposed a method for continuously manufacturing electrical laminates using unsaturated polyester resin that is liquid at room temperature in Japanese Patent Applications No. 53-77668 and No. 53-125541, etc. There is. Furthermore, as an example of manufacturing a laminate by heat and pressure molding using an unsaturated polyester resin that is solid at room temperature, Japanese Patent Application Laid-Open No. 48-29625,
There are many proposals such as JP-A-51-111885 and JP-A-52-92288, but these have not yet reached the stage of practical application. The cellulose-based unsaturated polyester resin laminate obtained by the method described above has extremely good electrical insulation properties, soldering heat resistance, mechanical strength, etc. under normal conditions, but its properties as a laminate deteriorate due to moisture absorption. It had the disadvantage of a large decrease in . Although the unsaturated polyester resin itself has excellent electrical insulation, heat resistance, and moisture resistance, it has poor adhesion to the cellulose that makes up the base material.
This is thought to be because the interface between the resin and the cellulose fibers peels off due to moisture absorption, and the amount of moisture absorbed increases accordingly, leading to a decrease in various performances. In view of this current situation, the present inventors have already conducted intensive research and found that by producing an unsaturated polyester resin laminate as a base material pre-impregnated with a compound having a methylol group, it has been found that It was discovered that it was possible to provide an electrical laminate with excellent properties, and also to eliminate the various drawbacks of the conventional unsaturated polyester resin laminate described above, and proposed the invention in Japanese Patent Application No. 53239/1983. Furthermore, in practical use, these electrical laminates and copper-clad laminates are usually punched out.
Shaping and drilling are often performed, and therefore excellent punching properties are required. Especially in recent years, with the miniaturization of electronic components and higher density of circuits,
Currently, more advanced processing characteristics are desired. Conventionally, unsaturated polyester and base laminates are made by impregnating crystalline polyester or polyester that is solid at room temperature with a crosslinking agent using a solvent, drying it to form a prepreg, and then heat-pressing it to create a laminate. I've been exposed to it. However, although the laminates made by these methods have a high glass transition temperature and excellent heat resistance, they have problems with punching workability, especially during low-temperature punching, which is usually performed at about 50 to 80°C. It was hot. Furthermore, in recent years, electrical laminates with excellent flame retardancy have been eagerly desired, as strict flame retardance requirements such as the US UL standards are now being required for this type of electrical laminates. As a result of intensive research to solve the above problems, the present inventors found that a mixture of (a) a halogen-containing unsaturated polyester resin and (b) an unsaturated polyester resin for hardness adjustment was used as a base material impregnating resin. Adopting a mixed resin whose glass transition temperature after curing is 20 to 80°C, using a base material that has been previously treated with a compound having a methylol group, and using a laminate and metal foil. By bonding the two with a flame-retardant adhesive, we were able to solve the above problems all at once. The present invention will be explained in detail below. First, the halogen-containing unsaturated polyester resin and the hardness-adjusting unsaturated polyester resin used in the present invention will be explained. In general, unsaturated polyester resins have a structural formula of unsaturated polyester chains, such as The raw materials include polyols such as ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, and 1,5-pentanediol, and saturated polybasic acids such as phthalic anhydride, isophthalic acid, terephthalic acid, and adipic acid. , sebacic acid, azelaic acid, and unsaturated polybasic acids such as maleic anhydride and fumaric acid are common, and the unsaturated polyester resin is a mixture of an unsaturated polyester and a crosslinking monomer. Styrene is commonly used as a crosslinking monomer, but other examples include α-methylstyrene, vinyltoluene, chlorostyrene, divinylbenzene, alkyl acrylates having 1 to 10 carbon atoms, alkyl methacrylates having 1 to 10 carbon atoms, and phthalic acid. Monomers such as diallyl and triallyl cyanurate can also be used. Also, styrene and a mixture thereof may be used. The amount of these crosslinking monomers used is
20-50% by weight of unsaturated polyester resin. The halogen-containing unsaturated polyester resin of the present invention is completely different from general unsaturated polyester resins, and contains a halogen in the unsaturated polyester molecular structure, and contains halogenated glycol as a polyol component and halogenated acid as an acid component. In addition to those in which unsaturated polyesters are synthesized using conventional methods, halogenated polyesters such as those produced by Japanese Patent Publication No. 46-8993 are also included. Examples of the halogenated glycol include 2,2-dibromo-neopentyl glycol, and examples of the halogenated acid include tetrabromophthalic acid, tetrachlorophthalic acid, chlorendoic acid, and acid anhydrides thereof. The halogen-containing unsaturated polyester resin is a mixture of the above-mentioned halogen-containing unsaturated polyester and a crosslinking monomer. As the crosslinking monomer, the same ones as those for general unsaturated polyester resins can be used. Therefore, commercially available chlorendo acid-based unsaturated polyester resins, such as those manufactured by Futsuker Co., Ltd.
HETRON, Dainippon Ink Polylite NA−281
Also suitable are reactive flame-retardant polyester resins in which bromine is introduced into unsaturated bonds in unsaturated polyesters, such as FMS-583, FPM-531, and FPM-231 manufactured by U-Pica Japan. The preferred halogen content of the halogen-containing unsaturated polyester resin of the present invention varies depending on flame retardant standards and additives used in combination for electrical laminates, and is difficult to limit, but for example, the halogen-containing unsaturated polyester resin alone In order to achieve UL-94 V0 or V1 class, it is necessary to contain 20% by weight of chlorine and 15 to 18% by weight of bromine in the resin. However, although halogen-containing unsaturated polyester resins have high flame retardancy, they generally have a relatively high glass transition temperature (hereinafter referred to as Tg) and have poor punching processability, especially during low-temperature punching, which is usually performed at about 50 to 80 degrees Celsius. Processability tends to be poor. In order to improve this drawback, a mixture of a halogen-containing unsaturated polyester resin and a hardness-adjusting unsaturated polyester resin containing a soft segment, the Tg of the cured product of the composition being 20 to 80°C,
It has been found that the objective can be achieved by using a mixed resin, preferably at a temperature of 30-70°C. That is,
The Tg of the cured composition is 20 to 80°C, preferably 30 to 80°C.
Excellent low-temperature punching properties can be obtained by using a mixture at 70°C. When the Tg is higher than the above range, the laminate should be
Although it is possible to carry out the punching process by heating it to a temperature higher than +10°C to +20°C, in that case, high-temperature punching would be required, which would deviate from the purpose of the present invention, which aims at low-temperature punching, which is frequently used in the industry. become. The glass transition temperature (Tg) is the temperature at which a polymer substance changes from a glass-like hard state to a rubber-like state when heated, and is a temperature unique to polymer substances with sufficiently large molecular weights. This Tg is measured by dilatometry, calorimetry, mechanical dispersion, or the like. The punching workability in the present invention is 1mmφ25.4mm
By a mold containing 23 consecutive pitch pins
In accordance with ASTM-D617-44 scoring criteria, a material is considered to have good punching workability if it is evaluated in the excellent to fair range for all evaluation items of end face, surface, and hole. The unsaturated polyester resin for hardness adjustment in the present invention is an unsaturated polyester resin containing a polyol component or an acid component of an unsaturated polyester that becomes a soft segment, and is not particularly limited. Commercially available soft and ultra-soft resins, such as Takeda Pharmaceutical's Polymer 6320F, Showa Kobunshi's Rigoratsu
70F, Tg of Mitsui Toatsu Esther F2240 etc. is usually 0
The blending amount of this unsaturated polyester resin for hardness adjustment, which can be used at ~50℃, depends on the halogen-containing polyester resin used, i.e., the type and amount of halogen, and Tg, and the unsaturated polyester resin used for hardness adjustment. Tg of saturated polyester resin,
Although it varies depending on the level of flame retardancy to be obtained and the level of low-temperature punching workability, it is generally desirable for the hardness-adjusting polyester resin to be in the range of 1 to 50%, preferably 10 to 35%. It is also possible to blend rubber, plasticizers, fillers, and other additives, but it is necessary to make sure that the cured resin composition obtained by blending these and curing falls within the Tg range specified in the present invention. needs to be adjusted. Rubbers include maleated polybutadiene and/or copolymers thereof, plasticizers include commercially available ester plasticizers made from adipic acid or phthalic acid and glycol, and epoxidized soybean oil.
Examples of inorganic substances include calcium carbonate, silicic anhydride, and titanium oxide, which are used as fillers for polyester resins. Furthermore, in the present invention, it is desirable to add an additive type flame retardant as an additive. Commercially available additive flame retardants, i.e., non-halogen phosphate esters and halogen-containing phosphate esters, such as trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, octyl diphenyl phosphate, tris (chloroethyl) phosphate, tris (dichloropropyl) phosphate, tris(chloropropyl) phosphate, bis(2,3
-dibromopropyl) 2,3-dichloropropyl phosphate, tris(2,3-dibromopropyl) phosphate, bis(chloropropyl) monooctyl phosphate, mixtures of these with halogen-containing additives, e.g. halogen-containing complex phosphate esters etc. can be given. Furthermore, inorganic flame retardants such as antimony oxide and aluminum hydroxide are also preferred. On the other hand, when curing, general-purpose organic peroxide,
A curing accelerator can be used if necessary.
Rather than using peroxydicarbonates, ketone peroxides, hydroperoxides, or diacyl peroxides as the peroxide used as a catalyst for curing the unsaturated polyester resin of the present invention, peroxyketals, dialkyl Use of one or more peroxides selected from peroxides and peroxyesters provides particularly favorable results in terms of solder heat resistance, electrical insulation properties, and adhesive properties. A good blending amount is about 0.5 to 2.0% based on the resin liquid. More preferred catalysts include peroxyketals such as 1-1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane,
1-1-bis(t-butylperoxy)cyclohexane, n-butyl-4,4-bis(t-butylperoxy)valerate, dialkyl peroxides such as di-t-butylperoxide, 2,5 -dimethyl-2,5-di(t-butylperoxy)hexyne-3, peroxy esters such as t-butylperoxyacetate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy oxylaurate, t
-butyl peroxybenzoate, etc. Next, the compound having a methylol group for pre-treating the base material will be explained. There are various compounds having a methylol group that can be used as a substrate treatment agent in the present invention. Resins obtained by addition condensation include melamine resins, urea resins, and modified resins thereof, and also include those in which part or all of the methylol group is etherified with a lower alcohol such as methanol or butanol. Specifically, the general formula (However, R ₁ = H, CH ₃ R ₂ = H, C ₁ to ₄ alkyl group) is an amidomethylol compound represented by
Among them, N-methylolacrylamide, N-
Preferred are methoxymethylol acrylamide, N-butoxymethylol acrylamide, N-methylol methacrylamide, N-methoxymethylol methacrylamide, N-butoxymethylol methacrylamide, and the like. One or two of these
A mixture of two or more types or a co-condensate of two or more types may be used. Further, as other specific examples, methylolmelamine and/or methylolguanamine are preferable, and these are initial condensates of formaldehyde and guanamines such as melamine or formoguanamine, acetoguanamine, propioguanamine, benzoguanamine, and adiposiguanamine, or their initial condensates. These include those in which part or all of the methylol group is etherified with a lower alcohol such as methanol or butanol. Furthermore, with these as main components, thermoplastic resins, various vegetable oils, modified products thereof, etc. may be mixed as appropriate for the purpose of improving mechanical properties, for example. Furthermore, better results can be obtained by mixing or condensing the following higher aliphatic derivatives in addition to the above-mentioned compounds having a methylol group such as methylolmelamine and/or methylolguanamine. Higher aliphatic derivatives include, for example, saturated fatty acids such as caprylic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, and stearic acid; Saturated fatty acids and esters of the above fatty acids with polyhydric alcohols such as ethylene glycol, polyethylene glycol, propylene glycol, glycerin, pentaerythritol, and sorbitol, aliphatic amides that are derivatives of the above fatty acids, and caprylic alcohol and lauryl alcohol , saturated or unsaturated higher alcohols such as myristyl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, linoleyl alcohol, ethers of higher alcohols and polyhydric alcohols, and aliphatic amines that are derivatives of higher alcohols. be able to. Oxyfatty acids such as ricinoleic acid and derivatives thereof can also be used in combination for the purpose of improving punching processability. In short, punching is achieved by having in the molecule both a group that can condense with the methylol group of the amino resin, such as a hydroxyl group, a carboxyl group, an amino group, an amide group, and a long-chain alkyl group that acts to weaken the cohesive force of the amino resin. These conditions are more preferable as a processing property agent. Although the number of higher aliphatic derivatives that satisfy these conditions is extremely large, according to the results of the studies conducted by the present inventors so far,
When the number of carbon atoms is 8 or more, the effect as a punching property modifier becomes remarkable, and oleic acid, oleyl alcohol, and derivatives thereof, such as oleic acid monoglyceride, oleic acid diglyceride, and oleic acid having 18 carbon atoms and one unsaturated group. It has also become clear that when oleic acid amide and oleylamine are used, the performance of the resulting laminate is well balanced and is a preferred embodiment of the present invention. The optimum amount of such a modifier to be used varies depending on the mixed resin composition used in the laminate, but it is usually within the range of 3 to 40 parts per 100 parts of the compound having a methylol group. It is in. Regarding the method of using the processing agent, either a compound having a methylol group or the compound and the above-mentioned modifier are mixed in the form of a solution or suspension, or the two are used by condensing them in advance. It may also depend on The methylol group-containing compounds of the present invention generally have a suitable affinity for both cellulose fibers and unsaturated polyester resins, making them useful for forming excellent composites, which in turn makes them excellent for electrical applications. Form a laminate. To obtain a pre-impregnated paper base material, for example, a solution of the above-mentioned methylol group-containing compound in water or alcohol as a solvent is prepared, and the paper base material is immersed in this solution.
This can be achieved by drying. The final amount of the methylol group-containing compound treatment agent deposited on the paper base is usually about 5 to 30%, preferably about 10 to 20%, based on the weight of the paper. By using a paper base material that has been subjected to such a pre-impregnation treatment, the bending strength is improved. The whitening phenomenon during punching is improved. Especially when exposed to humid environments,
Deterioration of solder heat resistance, adhesive strength of metal foil, and electrical insulation properties is slight. The cellulose base material used in the present invention refers to a paper base material mainly composed of cellulose fibers such as kraft paper and linter paper, or a cellulose base material such as cotton or rayon. In the present invention, paper substrates give more favorable results. As mentioned above, metal foil is laminated on a cured laminate consisting of a pretreated base material and a mixture of a halogen-containing unsaturated polyester resin and a hardness-adjusting unsaturated polyester resin (both are preferably liquid at room temperature). By adhering, the flame-retardant electrical laminate covered with metal foil of the present invention can be obtained, and the thickness of the adhesive layer is 5 to 100 μm, preferably 25 to 80 μm. The flame-retardant adhesive used in the present invention is not particularly limited, and may be an epoxy-based adhesive, a rubber phenol-based adhesive, a polyvinyl acetal phenol-based adhesive, or an adhesive obtained by making a combustible adhesive flame-retardant. Regarding the flame retardant method, for example, in the case of epoxy adhesives, some or all of the epoxy resin component is replaced with a halogen-containing epoxy resin or a halogen-containing monoepoxy compound, or a halogen-containing monoepoxy compound is added to this. This can be achieved by using flame retardants such as compounds, halogen-containing phosphorus compounds, antimony trioxide, zirconium compounds, and aluminum hydroxide. More specifically, diclycidyl ether of tetrabromobisphenol A, 2,2-
Dibromo-neopentyl glycol-diglycidyl ether, dibromocresol monoglycidyl ether and diglycidyl ether of bisphenol A can be cured with an amine curing agent or an acid anhydride curing agent. In addition, flame-retardant epoxy resins and polyamide resins such as polyamide amine resins, terminal amino group polybutadiene nitrile rubber,
Amine curing agents or mixtures of these curing agents are preferred as the adhesive of the present invention because the physical properties of the adhesive can be easily changed to desired ones by combining them. It is more difficult to make laminates flame retardant when they are thin, but according to the method of the present invention, flame retardancy of about 1 mm and 0.8 mm is achieved.
It is possible to make a laminate with sufficient flame retardancy even with a thin metal-clad laminate of a certain thickness. Note that the metal foil used in the present invention includes copper foil,
Especially when using electrolytic copper foil, corrosion resistance, etching resistance,
Preferable from the viewpoint of adhesion and the like. Other examples include electrolytic iron foil and aluminum foil. Regarding the production of the flame-retardant metal foil-clad electrical laminate of the present invention, the present inventors have already filed a patent application filed in 1973-
Before laminating the metal foil proposed in 83239, an adhesive is applied to the metal foil, and the heat-treated metal foil with adhesive is laminated with a cellulose substrate impregnated with unsaturated polyester resin. One of the preferred embodiments of the present invention is to apply a method of curing in a state. The metal foil-covered electrical laminate manufactured by the above method is flame retardant, has excellent punching workability and moisture resistance, and can be used as an electrical laminate for various purposes such as printed circuit boards. be able to. Next, the present invention will be explained in more detail with reference to Examples. Example 1 A kraft paper with a thickness of 285 μm was immersed in an 8% methanol solution of N-methylol acrylamide, taken out, heated at 120° C. for 20 minutes, and dried to obtain an impregnated base material. At this time, the amount of N-methylol acrylamide attached to the paper was 11.2%. While continuously conveying the five sheets treated in this way, a resin solution with the following composition, UPICA FPM231 (flame-retardant unsaturated polyester resin manufactured by Nippon Upica, 80 parts by weight, Polymer 6320F (unsaturated polyester resin manufactured by Takeda Pharmaceutical Co., Ltd.) 20 〃 Perhexa 3M A commercially available electrolytic copper foil (CF-T5 manufactured by Fukuda Metals) is impregnated with 1 part by weight of a curing catalyst made by Nippon Oil & Fats and is continuously rolled out using two pairs of rolls. Epikote 828 (epoxy resin manufactured by Ciel Chemical) as adhesive
35 parts by weight DER542 (brominated epoxy resin manufactured by Dow)
35 〃 Persamide 125 (Henkel Japanese polyamide resin)
20 〃 ATBN (unterminated amino group polybutadiene nitrile rubber manufactured by BF Gutudoritsu) 10 〃 was mixed with a blade coater to a thickness of 80 μm.
The film was coated on the film, then passed through a tunnel furnace for adhesive heat treatment at 100°C for 5 minutes, then laminated at the same time.Furthermore, a polyester film with a thickness of 50μm was laminated on the opposite side, and the temperature was increased. After cutting, it was continuously transferred to a tunnel-shaped hot stove at 110℃ for 30 minutes, and heated to 160℃×
Further heat treatment was performed for 10 minutes to obtain a single-sided copper-clad laminate with a thickness of approximately 1.6 mm. The performance is shown in Table 1. The glass transition temperature of the cured resin is approximately 60℃.
It was hot. Example 2 Oleic acid monoglyceride (Riken vitamin oil,
50 parts by weight of water in which 6 parts by weight of methylolmelamine (Nippon Carbide Kogyo, Nikaresin S-305) was dissolved was poured into 50 parts by weight of methanol in which 1.5 parts by weight of Rikemar OL-100) was dissolved, with strong stirring.
A suspension treatment solution was prepared. This treatment liquid has a thickness
285μm kraft paper (Tomoekawa Paper MKP-150)
After soaking and taking out, the treated paper base material was heated and dried at 120°C for 20 minutes. At this time, the amount of treatment agent attached to the paper was 13.8%. While continuously conveying the five sheets treated in this manner, they were impregnated with a resin liquid having the following composition (same as in Example 1): 80 parts by weight of U-Pica FPM-231, 1 part by weight of Polymer 6320F 20, and 1 part by weight of Pohexa 3M. 35 parts by weight of Epicoat 828 DER542 was applied as a flame-retardant adhesive (same as in Example 1) to a commercially available electrolytic copper foil (CF-T5 manufactured by Fukuda Metals) which was overlapped using a pair and continuously unwound. 35 parts by weight Versamide 125 20 parts by weight ATBN 10 parts by weight were mixed and coated to a thickness of 80 μm using a blade coater.
The film was coated on the film, then passed through a tunnel furnace for adhesive heat treatment at 100°C for 5 minutes, then laminated at the same time.Furthermore, a polyester film with a thickness of 50μm was laminated on the opposite side, and the temperature was increased. It was continuously transferred to a tunnel-shaped hot air oven at 110°C, and it took 30 minutes to pass through it. After cutting, 160℃×
Further heat treatment was performed for 10 minutes to obtain a single-sided copper-clad laminate with a thickness of approximately 1.6 mm. The performance is shown in Table 1. Naho, the glass transition temperature of the cured resin is approximately 60℃.
It was hot.

【table】

[Table] The test method is as follows. (1) Punching workability: 1mmφ25.4mm continuous pin23
Mold use including pieces. The punching temperature was 60 to 80°C. (2) Water absorption rate: JIS-C6481 (3) Flame resistance: UL-94 (4) Soldering heat resistance: JIS-C6481.

Claims (1)

[Claims] 1 (a) a halogen-containing unsaturated polyester resin;
(b) Multiple sheets of cellulose base material impregnated with a resin blend that has a Tg in the range of 20 to 80°C after curing, which is made by mixing an unsaturated polyester resin containing soft segments as a hardness adjusting resin. A flame-retardant metal foil-covered electrical laminate comprising a metal foil bonded to the surface of an insulating plate portion made of a laminate via a flame-retardant thermosetting resin adhesive layer with a thickness of 5 to 100 microns. 2. The laminate of item 1, wherein the cellulose base material is pre-impregnated with a compound having a methylol group. 3. The cellulose-based substrate according to item 1, which is pre-impregnated with a mixture or condensate of methylolmelamine and/or methylolguanamine and a higher aliphatic derivative having at least one group capable of condensing with a methylol group in the molecule. Laminated board. 4. The laminate according to any one of Items 1 to 3, wherein the flame-retardant adhesive comprises a flame-retardant epoxy resin and a polyamide amine curing agent. 5 The first flame-retardant adhesive layer has a thickness of 25 to 80μ
The laminate according to any one of Items 1 to 4. 6. The laminate according to any one of Items 1 to 5, wherein the proportion of the hardness-adjusting unsaturated polyester resin in the resin blend is 10 to 35%.