JPS60154406A - Cover lay thin material for protecting circuit - 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] III) Purpose of the Invention The present invention is suitable for use at room temperature (20°C) to relatively high temperature (360°C).
The present invention relates to a thin-walled caperley material for circuit preservation that has excellent adhesive properties and good moisture resistance. More specifically, when a mixture consisting of (4) an ethylene-acrylic acid copolymer and/or an ethylene-methacrylic acid copolymer and a saponified product of CB) an ethylene-vinyl acetate copolymer is heated at a temperature of 250° C. or lower, fish eye is generated. Extrude the resulting thin-walled product under conditions of 100°C to 4.
This is a thin-walled cover material for circuit protection that is obtained by heating and pressurizing at a temperature of 0.000 Celsius.It is not only a thin-walled cover material that has excellent heat resistance and electrical insulation properties, but also has thermal adhesive properties. The object of the present invention is to provide a thin-walled coupler for circuit protection.

([3 Background of the Invention] The semiconductor industry has expanded from integrated circuits to flight packs to MSLs.
, LSI, and ultra-LSI, and as a result, circuit density, reliability, and price reduction are progressing. In other words, higher density and multi-layer packaging, as well as smaller, thinner, and lighter equipment.

As we move towards higher quality and lower quantity, electrical insulation of circuit parts,
Coupler materials for circuit protection have come to play an important role for the purpose of preventing rust, protecting circuits from dirt, and damage. Generally, a film type in which an adhesive is applied to an insulating film and a liquid thermosetting or UV curing type adhesive resin paint are used as the cover material.

Currently, polyester films, polyimide films, polyamide films, and the like are used as Caperley films. Generally, a film with an average thickness of 25 microns and an adhesive made of thermosetting resin (for example, epoxy resin) are used.

The desired properties of a cover film are adhesion to copper foil, electrical insulation, heat resistance to solder, long shelf life, and excellent workability.

The polyester film and polyimide film described above have extremely poor adhesion to circuits and the like, so it is necessary to use an adhesive. This not only increases the number of work steps, but also reduces the heat resistance of the adhesive, resulting in a decrease in heat resistance and adhesion to solder at relatively high temperatures.

Furthermore, when an epoxy-based heat-resistant adhesive is used, problems such as poor moisture resistance and internal circuit deterioration due to humidity occur. Moreover, not only is the process of applying adhesive to the film and the drying that accompanies it complicated, but it also increases the amount of adhesive stress, reduces adhesive strength due to uneven application of adhesive, and high-temperature processing. Blisters may occur during processing, which may cause disconnection of the circuit wiring, and the purpose of coverage may not be achieved.

[11] Structure of the Invention In order to solve these problems, the present inventors have developed the conventional idea of heat-resistant polymer chemistry (4) Ethylene-acrylic acid copolymer and/or ethylene-acrylic acid copolymer and/or ethylene- methacrylic acid copolymer and (B) a saponified product of ethylene-vinyl acetate copolymer; The mixing ratio is 20 to 80% by weight.The mixture of '7 is extruded into a thin shape at a temperature of 250℃ or less under conditions that do not cause fissiniosis, and the resulting thin-walled product is extruded at 100℃.
The thin-walled coupler for circuit protection, which is obtained by heating and pressurizing at temperatures between 400°C and 400°C, has not only good heat resistance but also excellent adhesiveness even at high temperatures. , and found that it also has good moisture resistance.
We have arrived at the present invention.

[■] Effects of the Invention The thin-walled coupler for circuit protection obtained by the present invention exhibits the following effects (characteristics) including its manufacturing process.

(1) Since no thermosetting resin adhesive such as epoxy resin is used, there is no need to omit the adhesion process or the complicated drying process that accompanies that process.

(2) Electrical properties (e.g. insulation, withstand voltage).

◇ (3) It has good heat resistance and can not only withstand temperatures of 250°C or higher, but also can be used by applying pressure at temperatures of 100°C or higher. It can be well bonded to metal foils or plates such as copper foil without any problems.

(4) Excellent flexibility.

(5) and 9) Compared to conventionally used polyimide films and polyester films, the thin-walled product of the present invention has less dimensional stability because it is cross-linked at relatively high temperatures (200°C or higher), as described below. Not only is it excellent, but it also has good adhesion even at high temperatures, 6D, and has good adhesion and no residue. Id 6 is also extremely rare.

(6) In addition, even in the aditizo method, which has been used recently compared to the subtractive method, it is effective as a coupler for all kinds of circuit moldings because it has better adhesion to, for example, electroless plating circuits and patterns.

(7) Furthermore, even in the screen printing method, which has recently been used to manufacture high-density circuits with four turns, and the method of forming circuits with four turns using conductive paint, the coverlet thin-walled material that can be removed in the present invention is It also has good adhesion properties, giving stable quality to the circuit pattern, and the process is simple and easy.

(8) In addition, the above-mentioned adhesive properties can be used to moisture-proof all electronic devices other than covers for circuit protection.

It can be used as a protective coating to obtain environmental resistance such as gas resistance and dust resistance.

As described above, the resin layer of the present invention not only has the electrical properties such as insulation resistance and dielectric constant required for thin-walled couplers for circuit protection, but also has dimensional stability, heat resistance, chemical resistance, moisture resistance, etc. The protective strength of the flexible base material is good, and the bending durability in the valley shows flexibility that has not been previously available. In addition, with respect to adhesion to metal thin foil, it does not require an adhesive and has the characteristics of showing good adhesion even at relatively high temperatures simply by thermocompression bonding.

[■] Detailed description of the invention (N Ethylene-acrylic acid copolymer and ethylene-medacrylic acid copolymer The ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer used in the present invention are Acrylic acid or ethylene and methacrylic acid are heated under high pressure (generally 50 to 97 cm2 or more, preferably 100 kg)
/cIn2 or more) in the presence of a free radical generator (usually an organic peroxide). The copolymerization ratio of acrylic acid or methacrylic acid in these copolymers is 1 to 50% by weight, preferably 5 to 50% by weight. If the copolymerization ratio of acrylic acid or methacrylic acid in these copolymers is less than 1% by weight, a uniformly thin product cannot be obtained.

On the other hand, if it exceeds 50% by weight, the softening point will be low.
Difficult to handle at room temperature.

(B) Saponified product of ethylene-vinyl acetate copolymer Furthermore, the saponified product of ethylene-vinyl acetate copolymer used in the present invention can be obtained by saponifying (hydrolyzing) ethylene-vinyl acetate copolymer. . Hydrolysis is generally carried out using caustic soda in methyl alcohol. In producing the saponified product of the present invention, it is usually desirable to have a hydrolysis rate of 90 or more. The raw material, ethylene-vinyl acetate copolymer, is a mixture of ethylene and vinegar.
It is obtained by copolymerizing the ethylene-acrylic acid group polymer and the ethylene-methacrylic acid copolymer using the same method as the above-mentioned ethylene-acrylic acid group polymer and ethylene-methacrylic acid copolymer. The copolymerization ratio of vinyl acetate in this ethylene-vinyl acetate copolymer is generally 1 to 60% by weight;
0% by weight is preferred. If the copolymerization ratio of vinyl acetate in this copolymer is less than 1% by weight, a uniformly thin product cannot be obtained. On the other hand, if it exceeds 60% by weight, the softening point will drop and handling at room temperature will become difficult.

Saponified products of these ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, and ethylene-vinyl acetate copolymers are industrially produced and used in a wide range of fields, and their manufacture The method is also well known.

(Q Mixing ratio The mixing ratio of the ethylene-acrylic acid copolymer and/or ethylene-tutaacrylic acid copolymer in the mixture of the present invention is 20 to 80% by weight (i.e., ethylene-vinyl acetate copolymer). The mixing ratio is preferably 8.0 to 20% by weight), 25 to 70% by weight, particularly 30 to
70% by weight is preferred. If the mixing ratio of the ethylene-acrylic acid copolymer τ and/or the ethylene-methacrylic acid copolymer in these mixtures is less than 20% by weight, the number of hydroxyl groups (-COOH) will be lower than the hydroxyl groups (- Since the number of OH groups is smaller than that of OH), OH groups that do not contribute to the condensation reaction remain, and heat resistance does not improve.

On the other hand, if it exceeds 80% by weight, on the contrary, there are too many carboxyl groups contributing to the condensation reaction, and -unreacted groups remain, which is not preferable because heat resistance and moisture resistance are not improved.

(D) Mixing method The mixture of the present invention can be produced by uniformly mixing the saponified product of the above ethylene-acrylic acid and/or ethylene-methacrylic acid copolymer and ethylene-vinyl acetate copolymer. be able to. As a mixing method, tri-blending may be performed using a mixer such as a Henschel mixer, which is commonly used in the field of olefin polymers, or mixing may be performed using a mixer such as a Banbury mixer, kneader, roll mill, or screw extruder. It can be obtained by melt-kneading using a machine. At this time, a homogeneous mixture can be produced by triblending in advance and melting and kneading the resulting mixture. It should be noted that the ethylene-acrylic acid and/or ethylene-methacrylic acid copolymer used for melt cross-fertilization has a cal? It is necessary that the phosphoric acid group (-〇〇OH) and the hydroxyl group (-OH) of the saponified ethylene-vinyl acetate copolymer essentially not undergo a crosslinking reaction (condensation reaction). good). From this, the melting temperature is the temperature at which the saponified products of these ethylene-acrylic acid copolymers and/or ethylene-methacrylic acid copolymers and ethylene-vinyl acetate copolymers melt, but the crosslinking reaction does not occur. The melting temperature is the temperature at which no fisheye occurs (c).The melting temperature varies depending on the presence or absence of a crosslinking accelerator described below, as well as their type and amount added, but it is usually 250°C or lower when no crosslinking accelerator is incorporated. ℃, especially 100 to 150℃
is preferred. Temperatures below 100°C are particularly unfavorable because these resins are not completely melted.

On the other hand, when adding (blending) a crosslinking accelerator, it is generally carried out at a temperature of 140°C or lower and 100°C or higher.

To produce this mixture, oxygen is commonly used in the field of olefinic polymers.

Additives such as light (ultraviolet) and heat stabilizers, metal deterioration inhibitors, flame retardants, electrical property improvers, antistatic agents, lubricants, processability improvers, and tack improvers can be added to the present invention. It may be added as long as it does not impair the characteristics (physical properties) of the thin-walled material. Furthermore, epoxy compound m1)
- The oxidation of ethylene-acrylic acid copolymers and/or ethylene-methacrylic acid copolymers and ethylene-vinyl acetate copolymers as described above by adding crosslinking accelerators such as toluenesulfonic acid and At-impropoxide. The crosslinking with the compound can be further completed. The amount added is usually at most 0.1 part by weight (preferably 0.01 to 0.05 part by weight) per 100 parts by weight of these resins. Furthermore, it is also possible to improve the insulation properties by adding ceramics having insulation properties such as alumina and silicon nitride. Furthermore, inorganic powder,
The functionality of the present invention can be further improved by filling it with glass fibers, glass beads, etc.

(Production of thin-walled products) When the thin-walled products of the present invention are used in the form of a film or sheet, T-Guy film, which is commonly used in the field of thermoplastic resins, is widely used when producing films by the inflation method. A thin-walled product can be obtained by extruding it into a film or sheet using an extruder.At this time, the extrusion temperature is 2.
The temperature is below 50°C. When extruded at a temperature exceeding 250°C, part of the saponified product of ethylene-acrylic acid copolymer and/or ethylene-methacrylic acid copolymer and ethylene-vinyl acetate copolymer crosslinks, A homogeneous extrudate cannot be obtained due to the formation of gel-like particles. For these reasons, the extrusion temperature is in the same temperature range as in the case of the melt crosslinking described above, regardless of whether a crosslinking accelerator is added (blended) or not.

In any of the above cases, after manufacturing the thin-walled article, the thin-walled article with good transparency is obtained by rapidly cooling it in a water-cooling roll or water bath to prevent adhesion between the thin-walled article or the thin-walled article and a take-up roll. can get. The thickness of the thin-walled product thus obtained is generally from 5 microns to 400 microns.

(g) (Heat/pressure treatment Thin-walled products obtained as described above behave in the same way as normal thin-walled products because crosslinking has hardly progressed. To impart heat resistance to the thin-walled products. It is important to heat and pressurize in the range of 100 to 400℃.
20-30 minutes in the range of 00-160℃, 160-24
By heating and pressurizing for 10 to 20 minutes in the range of 0°C and for 10 minutes or less in the range of 240 to 400°C, a crosslinking reaction (condensation reaction) occurs within the resin, and the heat resistance is significantly improved.

Since the thin-walled article obtained by the present invention exhibits thermocompression adhesion (adhesiveness) at a temperature of 100° C. or higher, the effects of the present invention are further expanded by performing the crosslinking treatment and adhesion to the metal at the same time. That is, ethylene-acrylic acid copolymer and/or
Alternatively, a mixture of an ethylene-methacrylic acid copolymer and a saponified ethylene-vinyl acetate copolymer exhibits thermoplasticity at a temperature of 250°C or lower, but by heating and pressurizing the mixture to a temperature of 100°C or higher. It undergoes a crosslinking reaction and exhibits adhesive properties at the same time.

The following two methods can be used for producing Kapalei thin-walled products depending on the intended use.

As a first method, the thin-walled article may be placed on the surface of an article requiring surface protection (for example, a circuit-formed article), and heated and pressurized to the above-mentioned temperature range as it is. If air is to be trapped between the protective surface and the thin-walled object, it is necessary to use a heat press, heat roll, or the like to perform thermocompression bonding. Heating temperature is 3
Although it is possible to obtain products with sufficient adhesion even below 00°C, if heat resistance is required, the temperature as high as possible (
Usually, it is preferable to carry out pressure bonding at a temperature of 200 to 300°C. A thin-walled product with good heat resistance and adhesion can be obtained by heat-compression bonding at a temperature 10°C to 20°C higher than the required heat resistance temperature.

Even in the case of a surface that requires protection (for example, a circuit forming board), the thin-walled product of the present invention exhibits thermoplasticity before being heated and compressed, so it can sufficiently follow uneven parts. It goes without saying that even if the material has a specific shape, the surface can be uniformly covered. In addition, it is possible to adhere to any surface even if the adhesive has an irregular cross section or a curved surface by devising a device (for example, a Lux mold) that can uniformly heat and press the adhesive onto the surface.

The second method is to apply a method commonly used in manufacturing multilayer laminates.

That is, the thin-walled product obtained as described above is uniformly distributed between each laminate, temporarily bonded at 120 to 250°C, and then finished by heating and pressing at a temperature of 250°C or higher. This method proposes a method in which multilayer molding is possible by temporarily adhering each layer one by one, and finally laminating all the layers and subjecting them to heat and pressure treatment.

The thin-walled coverlet for circuit protection obtained by the present invention can be used as a thin-walled coverlet (film or sheet) for protecting the surface of all types of equipment and circuit moldings since it exhibits the above-mentioned effects.

(Vl) Examples and Comparative Examples The present invention will now be explained in more detail with reference to Examples.

In the Examples and Comparative Examples, the heat resistance test was performed using the obtained films under UL796 (Printed Wiring Board) 7.
The film was placed on a glass epoxy printed circuit board with the test pattern shown in Figure 1 at the thermocompression temperature shown in Table 1 for 10 minutes (3 minutes in Comparative Example 3).
It was heat-pressed. The covered printed circuit board was heated in a No. 2 bath with lead/tin = 55745 (weight ratio) held at 220°C and lead/tin = 9o/lO (weight ratio) held at 300°C.
It was evaluated by floating it in a solder bath with a weight ratio of 20 seconds and 180 seconds.

Examples 1 to 5, Comparative Examples 1 to 5 Melt flow index (measured according to JIS K-6760 at a temperature of 190°C and a load of 2.16 kg, hereinafter referred to as rM, 1.J) is 300 g/l ′
Ethylene-acrylic acid copolymer (density 0.9
54i/cm', acrylic acid copolymerization ratio 20% by weight)
100 parts by weight and vinyl acetate copolymerization ratio is 28% by weight
Saponified product obtained by saponifying the ethylene-vinyl acetate copolymer (saponification degree 97.5%, M
, 1.75, 9/10 min, density 0.9519/cm'
) 100 parts by weight were triblended for 5 minutes using a Henschel mixer. The obtained mixture [hereinafter referred to as "mixture (4)"] was transferred to an extruder equipped with a T-die (diameter: 40 mm).
A film (thickness: 50 microns, 100 microns) was formed using a cylinder with a die width of 30 m, a rotation speed of 85 rpm, and a film (thickness: 50 microns, 100 microns) under the conditions shown in Table 1. (Examples 1 to 4, Comparative Examples 1 to 3). In addition, M, 1. Except for using an ethylene-methacrylic acid copolymer (density 0.95097 cm', methacrylic acid copolymerization ratio 25% by weight) whose A film was produced from the resulting mixture in the same manner as described above (Example 5).Furthermore, the ethylene-acrylic acid copolymer (hereinafter referred to as rEAAJ) used in Example 1 was used. Comparative Example 4) and a saponified product of ethylene-vinyl acetate copolymer (hereinafter referred to as "saponified product"; Comparative Example 5) were produced into films in the same manner as described above.

(Blank below) Each film obtained in this way was heated at 250°C and 30°C.
A heat resistance test was carried out using a hot press machine at 00° C. for 10 minutes each, and a heat resistance test was carried out on the test mother turn at 20' and 9/cl (gauge pressure), respectively. All of the materials obtained in Examples 1 to 5 were interlayered with a paste insulating material.

No peeling, cracking, or other deformation was observed between the copper circuits. In addition, in the product obtained in Comparative Example 2, some melting was observed in Kapaley at 220 ° C.
It had peeled off from the copper circuit. Furthermore, in all of the caplets obtained in Comparative Examples 4 and 5, melting was observed at 220° C., and the caplets did not retain their original shapes.

Patent applicant: Showa Denko Co., Ltd. Agent: Patent attorney Sei Kikuchi

Claims (1)

[Scope of Claims] A mixture consisting of (N) an ethylene-acrylic acid copolymer and/or an ethylene-methacrylic acid copolymer and (Bl) a saponified product of an ethylene-vinyl acetate copolymer; The mixing ratio of the ethylene-acrylic acid copolymer and/or the ethylene-methacrylic acid copolymer is 20 to 80% by weight, and this mixture is extruded into a thin wall at a temperature of 250°C or less under conditions that do not cause fishy eyes. A thin-walled coverage article for circuit protection, characterized in that it is obtained by heating and pressurizing the resulting thin-walled article at a temperature of 100°C to 400°C.