JPH0356270B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention relates to an electronic component series in which a large number of electronic components with lead wires are arranged in a sagging pattern so that the lead wires are located in parallel, and the outer ends of the lead wires are not coated with adhesive. This is a heat-sealable adhesive tape that is sandwiched between two tape base materials, a base material and an adhesive-coated base material, for connection and maintenance. That is, in lead taping of electronic components, a taping machine is used to apply a heat-sensitive fixing method to electronic components such as resistive elements, capacitor elements, capacitive elements, and transistor elements with lead wires to permanently bond electronic components. I have been able to get connections. The present invention relates to improvements in heat-sealable adhesive tapes used for belt taping. Conventional technology A holding structure for holding electronic components in a sagging arrangement with lead wires, in which electronic components are sandwiched between a room-temperature adhesive tape and a non-adhesive tape, was developed in 1977-12368.
As shown in the publication, since the pressure-sensitive adhesive tape is a room-temperature adhesive type, the pressure-sensitive adhesive tends to flow internally due to small stress, resulting in inconvenient phenomena such as misalignment of the lead wire. This has the disadvantage that accurate holding and fixing cannot be achieved over a long period of time. In addition, in a sagging arrangement holding structure in which electronic components with lead wires are sandwiched between two tape base materials, one of the tape base materials is coated with a pressure-sensitive adhesive.
An example of a holding structure in which an electronic component is sandwiched between an adhesive tape using a heat-pressure sensitive adhesive containing 100 parts by weight and 50 to 200 parts by weight of a heat-melting resin and a tape base material to which no adhesive has been applied (Japanese Patent Laid-Open No. 56-13040).
However, in this case the pressure sensitive adhesive 100
It has been shown that when 200 parts by weight or more of hot-melt resin is used, the initial adhesive strength of the pressure-sensitive adhesive is weak and the adhesive becomes brittle. Problems to be Solved by the Invention The purpose of the present invention is to improve a heat-sensitive adhesive for holding a series of electronic components, so that when the adhesive tape is unwound when used, it does not cause blocking and pins. The purpose of this invention is to obtain a heat-sealable adhesive tape that has high drawing strength and good heat resistance retention properties. Means to Solve the Problem In other words, as a result of intensive research, the inventors found that a heat-melting resin with a softening point of medium to high temperature (temperatures of 60 to 150°C is referred to as medium to high temperature in this specification) is used as an acrylic pressure-sensitive adhesive. If it is added in large excess of about twice or more to the adhesive, blocking will not occur, the pin pull-out strength after hot melt bonding will increase, and high temperature retention (meaning retention at 50°C) will be achieved. ) was also found to be excellent. At this time, if a small amount of low softening point (59°C or less) resin or viscous liquid resin is added, the brittleness of the hot melt adhesive is improved due to the balance of the three types of blended composition, and there is no blocking and the adhesive strength is increased. We have now achieved a heat-sealable adhesive tape for holding electronic components that has excellent high-temperature retention properties. The composition of the present invention is as follows: (a) based on 100 parts by weight of the solid content of the acrylic pressure-sensitive adhesive, (b) a softening point of 60°C that has good compatibility with the pressure-sensitive adhesive;
~150℃ medium-high temperature softening point thermofusible resin 210~400
parts by weight (preferably 210 to 300 parts by weight) and (c) a softening point of 59°C with good compatibility with the pressure-sensitive adhesive.
Low softening point resin or viscosity below 10~100000cps
1 to 100 parts by weight (preferably 5 to 80 parts by weight) of a room-temperature viscous liquid resin of 1 to 100 parts by weight (preferably 5 to 80 parts by weight) is applied to a tape base material for thermal fusion bonding for holding electronic components. It is a mold adhesive tape. In the present invention, the softening point is a softening point measured by the ring and ball method specified in K2531 of the Japanese Industrial Standards (JIS). In addition, viscosity means the viscosity at 25°C measured by the method specified in K6833 of the Japanese Industrial Standards (JIS). The components of the present invention will be explained in detail below. (Acrylic pressure-sensitive adhesive) In the present invention, acrylic pressure-sensitive adhesives include methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, and octyl acrylate. , acrylic esters such as decyl acrylate, methyl methacrylate,
A suitable homopolymer or copolymer of esters such as methacrylic acid esters such as ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, octyl methacrylate, and decyl methacrylate is used. Acrylic pressure-sensitive adhesive obtained by dissolving in a solvent, or these esters and acrylic acid, methacrylic acid, itaconic acid,
An acrylic pressure-sensitive adhesive obtained by dissolving a copolymer with a vinyl compound having a functional group such as crotonic acid or maleic acid in a suitable solvent is used.
When using a copolymer with this functional group, a small amount of organic crosslinking agent such as epoxy or isocyanate that reacts with the functional group may be added to further increase the heat resistance and cohesive strength of the desired hot-melt adhesive. is also possible. (Medium-high softening point thermofusible resin) In the present invention, the mid-high softening point thermofusible resin includes derivatives of rosin and modified rosin (modified rosin means hydrogenated rosin, polymerized rosin, etc.). refers to esters such as methyl ester, glycerin ester, triethylene glycol ester, and pentaerythritol ester), polyterpene resins (i.e., α-
(means pinene polymer, β-pinene polymer, dipentene polymer, etc.), terpene modified resin (means terpene-phenol, α-pinene-phenol copolymer, etc.), aliphatic carbonization Hydrogen resins (i.e. polymers of olefins,
cyclopentadiene resins, aromatic hydrocarbon resins (meaning polymers of petroleum fractions with 9 carbon atoms), phenolic resins (novolac One or more types selected from the group consisting of styrene resins, xylene resins, and coumaron indene resins are used. The main compound of the pressure-sensitive adhesive applied to the tape of the present invention is a mid-to-high temperature melting resin with a softening point of
A temperature of 150° C. or higher is not desirable because a large amount of heat is required to activate the pressure-sensitive adhesive. Further, the matters to be relied upon regarding the blending ratio of the hot-melt resin are as follows. When the amount of hot melt resin is 210 parts or more, i.e. in excess, heat fusion properties are improved, pin pull-out strength is improved (i.e., adhesion is improved), and retention at high temperatures (i.e., lead wire connection strength at 50°C) is improved. ) is improved (it can also be said that heat resistance is improved, and heat resistant retention is also improved), there is no blocking during tape rewinding, and if the hot melt resin is in excess of 400 parts or more, Pressure sensitive adhesive becomes brittle. (Low softening point resin and room temperature viscous liquid resin) The low softening point resin and room temperature viscosity liquid resin in the present invention include rosin and modified rosin derivatives, polyterpene resins, terpene modified resins, carbonized aliphatic resins. One or more types selected from the group of hydrogen resins, aromatic hydrocarbon resins, phenol resins, styrene resins, and xylene resins are used. In addition, the matters to be relied upon regarding the blending ratio of low softening point resins or room temperature viscous liquid resins are as follows:
It is as follows. A low softening point resin or viscous liquid resin with a softening point of 59°C or less is used as a brittleness improvement modifier in a mixed system of an acrylic pressure-sensitive adhesive and a medium-high softening point heat-melting resin. parts by weight). In other words, an excessive amount (100 parts or more) of a low softening point resin with a softening point of 59°C or less or a liquid resin that is viscous at room temperature.
It is undesirable to add it to the main composition because the hot-melt adhesive tends to soften at high temperatures (about 40 to 50° C.) after heat fusion, and the adhesive strength is poor. Therefore, the selection and blending amount of the low softening point resin and room temperature viscous liquid resin depend on the blending ratio of the acrylic pressure-sensitive adhesive and the mid-high softening point thermofusible resin, the type of the mid-high softening point thermofusible resin, and The physical properties of the pressure-sensitive adhesive are appropriately selected depending on the softening point (molecular weight) so as to meet the purpose. (Base material for tape) Examples of the base material for tape in the present invention include papers such as crepe paper, kraft paper, and Japanese paper, plastic films such as polyethylene film, polypropylene film, and polyester film;
Metal foils such as aluminum foil and copper foil, cloths such as cotton cloth and glass cloth can be used alone or as a composite. EXAMPLES The present invention will be described in more detail with reference to Examples below, but the following Examples are not intended to limit the present invention in any way. Example 1 Using lauryl peroxide as an initiator, 94 parts by weight of butyl acrylate and 6 parts by weight of acrylic acid were mixed in toluene at a temperature of 80°C for 7 hours at a monomer concentration of 60% by weight under a nitrogen stream. This was then copolymerized to produce an acrylic pressure-sensitive adhesive solution.
For this pressure-sensitive adhesive, per 100 parts by weight of its solid content, Hi-Resin #60 [a product of Toho Oil Resins Co., Ltd., a thermoplastic hydrocarbon resin made by copolymerizing aromatic olefin and diolefin] , the softening point is 60℃. ]250 parts by weight and ester gum
HT [A product of Arakawa Chemical Industry Co., Ltd., triethylene glycol ester of hydrogenated rosin, and its viscosity is 14,000 cps. ] Add 10 parts by weight,
Further, toluene was added and mixed for dilution or dissolution to obtain a hot-melt bonding solution with a solid content of 60% by weight. This hot-melt adhesive liquid was applied to crepe paper with a basis weight of 75 g/m ² so that the thickness after drying would be 30 μm, and dried at 120° C. for 3 minutes to obtain an adhesive tape with a width of 13 mm. This is called sample A. Example 2 Using benzoyl peroxide as an initiator, 92 parts by weight of 2-ethylhexyl acrylate and 8 parts by weight of acrylic acid were mixed at a monomer concentration of 50% under a nitrogen stream.
Copolymerization was carried out in toluene at a temperature of 80° C. for 8 hours in terms of weight percent to prepare an acrylic pressure-sensitive adhesive liquid. For each 100 parts by weight of the solid content of this pressure-sensitive adhesive, Hytanol 1501 (a novolak-type alkylphenol resin manufactured by Hitachi Chemical Co., Ltd., having a softening point of 90°C) was added. ] 250 parts by weight and dimer resin [a modified terpene copolymer manufactured by Yasushi Oil Industries Co., Ltd., with a viscosity of 30,000 cps. ]
Added 5 parts by weight to further increase the solid content concentration to 60% by weight.
Toluene was added so that the mixture was stirred and dissolved to obtain a hot-melt adhesive liquid. An adhesive tape was produced in the same manner as in Example 1. This is designated as sample RO. Example 3 Using lauryl peroxide as an initiator, 2-
A monomer mixture of ethylhexyl acrylate/butyl acrylate/acrylic acid in a weight ratio of 40/54/6 was copolymerized in toluene at a temperature of 80°C for 8 hours at a monomer concentration of 60% by weight under a nitrogen stream. An acrylic pressure-sensitive adhesive solution was prepared. Its solid content for this pressure sensitive adhesive
100 parts by weight, Petrosine #130 [an aromatic hydrocarbon resin manufactured by Mitsui Petrochemical Industries, Ltd., with a softening point of 130°C. ] 220 parts by weight and Picolastic A-50 (a styrene resin manufactured by Hercules Co., Ltd., with a softening point of 50° C.). ] 80 parts by weight were mixed, toluene was added so that the solid content concentration was 65% by weight, and the mixture was stirred and dissolved to obtain a hot-melt adhesive liquid. Next, an adhesive tape was produced in the same manner as in Example 1. This is designated as sample C. Example 4 Using lauryl peroxide as an initiator, a mixture of butyl acrylate/acrylic acid in a weight ratio of 96/4 was prepared in toluene at a temperature of 880° C. for 8 hours at a monomer concentration of 60% by weight under a nitrogen stream. Copolymerization was carried out over a period of time to obtain an acrylic pressure-sensitive adhesive liquid. Its solid content for this pressure sensitive adhesive
Per 100 parts by weight, YS Resin Px1000 (a terpene-based resin manufactured by Yasushi Oil Industries Co., Ltd., with a softening point of 100
It is ℃. ] 300 parts and ester gum KE-190
[It is a triethylene glycol ester of modified rosin manufactured by Arakawa Chemical Industry Co., Ltd., and has a viscosity of 7500 cps. ] 80 parts by weight, and further increase the solid content concentration.
Toluene was added to give a concentration of 70% by weight, and the mixture was stirred and dissolved to obtain a hot-melt adhesive liquid. Next, an adhesive tape was produced in the same manner as in Example 1. This is designated as sample 2. (Pin pull-out strength) Test method The tapes to be tested (i.e., the adhesive tapes of samples I to D with a width of 13 mm obtained in the above examples and commercially available adhesive tapes) and thick kraft paper with a basis weight of 200 g/m ² (width 18 mm) with a lead wire of 0.5 mm in diameter (the product obtained in this way, that is, the combination of the lead wire sandwiched between the adhesive tape and the kraft paper is called a preliminary sample), at 60°C. 80℃,
Crimping force 10Kg/ ^cm2 under hot air conditions of 100℃ and 120℃
A sample for measurement (in the form of vertical taping) was prepared by passing the preliminary sample between 1 sec rubber rolls. After heat-sealing and crimping, the wire was left at room temperature (23° C. x 65% RH) for 30 minutes, and the pull-out strength of the lead wire was measured using an Instron type tensile tester at a pulling speed of 300 mm/min. Test Results The measurement results are shown in Table 1.

[Table] According to the results shown in Table 1, samples A to D of the present invention were heat-melted (fused) by performing heat-pressing treatment at 60 to 120°C, and after heat treatment, It can be seen that when cooled, it becomes adhesive and provides great pin pull-out strength. (Paper Peeling Test) A thick kraft paper adhesion test was conducted on Samples I to D and commercially available adhesive tapes. Test method and evaluation method 200g/m ² thick kraft paper (18mm width) and each adhesive tape (13mm width) were heated (hot air) at 60, 80, and 100℃ using a 10Kg/cm ² lsec rubber roll. Heat-sealed and heated under 23℃ (65%RH) for 30 minutes.
After being left for a minute, the adhesive tape was strongly peeled off by hand, and the state of tearing (paper peeling) on the surface of the kraft paper was visually determined. Test Results The test results are shown in Table 2. In Table 2, the following symbols were used. ◎: 100% of the paper was peeled 〇: 50% to 99% of the paper was peeled △: 1% to 49% of the paper was peeled ×: 0% of the paper was peeled (not peeled)

[Table] From the results shown in Table 2, it can be seen that the adhesive properties of Samples A to D of the present invention are excellent in the heating temperature treatment at 60 to 1000°C. (Blocking properties and high temperature retention properties) Samples A to D and commercially available adhesive tapes were tested for blocking properties and high temperature retention properties. Samples were prepared in the same manner as when measuring pin pullout strength. Test method 1) After storing the tape at 50°C for one month, the tape was rewound and the blocking properties at that time were examined. 2) After applying a static load of 500 g to the pin in a dry oven at 50°C, the time (minutes) until the pin came out was measured. Test Results Table 3 shows the test results for blocking properties and high temperature retention properties. Table 3 shows that the adhesive tape of the present invention has excellent storage durability under high temperatures and does not cause blocking;
It also shows that after heat fusion bonding, it has excellent retention under high temperatures.

[Table] Effects of the Invention As is clear from the above examples, the heat-sealable adhesive tape according to the present invention has stable characteristics at room temperature and high temperature in belt taping using the heat-sealable adhesive tape. When using this tape, it does not block when unwinding the tape, has excellent retention under high temperatures, and has excellent permanent adhesion and high adhesive properties (specifically, heat fusion (greater pin pullout strength).

Claims (1)

[Claims] 1. (a) Based on 100 parts by weight of the solid content of the acrylic pressure-sensitive adhesive, (b) A softening point of 60°C to 150°C with good compatibility with the adhesive.
210 to 400 parts by weight of a heat-melting resin with a medium-to-high softening point of °C and (C) a low softening point resin with a softening point of 59 °C or less or a room-temperature viscous liquid resin with a viscosity of 10 to 100,000 cps that has good compatibility with the adhesive. A heat-sealable adhesive tape for holding electronic components, which is formed by coating a tape base material with a heat-melting adhesive containing 1 to 100 parts by weight.